linux/kernel/audit.c

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/* audit.c -- Auditing support
* Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
* System-call specific features have moved to auditsc.c
*
* Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Written by Rickard E. (Rik) Faith <faith@redhat.com>
*
* Goals: 1) Integrate fully with Security Modules.
* 2) Minimal run-time overhead:
* a) Minimal when syscall auditing is disabled (audit_enable=0).
* b) Small when syscall auditing is enabled and no audit record
* is generated (defer as much work as possible to record
* generation time):
* i) context is allocated,
* ii) names from getname are stored without a copy, and
* iii) inode information stored from path_lookup.
* 3) Ability to disable syscall auditing at boot time (audit=0).
* 4) Usable by other parts of the kernel (if audit_log* is called,
* then a syscall record will be generated automatically for the
* current syscall).
* 5) Netlink interface to user-space.
* 6) Support low-overhead kernel-based filtering to minimize the
* information that must be passed to user-space.
*
* Example user-space utilities: http://people.redhat.com/sgrubb/audit/
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/file.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/atomic.h>
#include <linux/mm.h>
#include <linux/export.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 09:04:11 +01:00
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/kthread.h>
#include <linux/kernel.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <linux/skbuff.h>
#ifdef CONFIG_SECURITY
#include <linux/security.h>
#endif
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
#include <net/netns/generic.h>
#include "audit.h"
/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
* (Initialization happens after skb_init is called.) */
#define AUDIT_DISABLED -1
#define AUDIT_UNINITIALIZED 0
#define AUDIT_INITIALIZED 1
static int audit_initialized;
#define AUDIT_OFF 0
#define AUDIT_ON 1
#define AUDIT_LOCKED 2
u32 audit_enabled;
u32 audit_ever_enabled;
EXPORT_SYMBOL_GPL(audit_enabled);
/* Default state when kernel boots without any parameters. */
static u32 audit_default;
/* If auditing cannot proceed, audit_failure selects what happens. */
static u32 audit_failure = AUDIT_FAIL_PRINTK;
audit: netlink socket can be auto-bound to pid other than current->pid (v2) From: Pavel Emelyanov <xemul@openvz.org> This patch is based on the one from Thomas. The kauditd_thread() calls the netlink_unicast() and passes the audit_pid to it. The audit_pid, in turn, is received from the user space and the tool (I've checked the audit v1.6.9) uses getpid() to pass one in the kernel. Besides, this tool doesn't bind the netlink socket to this id, but simply creates it allowing the kernel to auto-bind one. That's the preamble. The problem is that netlink_autobind() _does_not_ guarantees that the socket will be auto-bound to the current pid. Instead it uses the current pid as a hint to start looking for a free id. So, in case of conflict, the audit messages can be sent to a wrong socket. This can happen (it's unlikely, but can be) in case some task opens more than one netlink sockets and then the audit one starts - in this case the audit's pid can be busy and its socket will be bound to another id. The proposal is to introduce an audit_nlk_pid in audit subsys, that will point to the netlink socket to send packets to. It will most often be equal to audit_pid. The socket id can be got from the skb's netlink CB right in the audit_receive_msg. The audit_nlk_pid reset to 0 is not required, since all the decisions are taken based on audit_pid value only. Later, if the audit tools will bind the socket themselves, the kernel will have to provide a way to setup the audit_nlk_pid as well. A good side effect of this patch is that audit_pid can later be converted to struct pid, as it is not longer safe to use pid_t-s in the presence of pid namespaces. But audit code still uses the tgid from task_struct in the audit_signal_info and in the audit_filter_syscall. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-20 23:39:41 +01:00
/*
* If audit records are to be written to the netlink socket, audit_pid
* contains the pid of the auditd process and audit_nlk_portid contains
* the portid to use to send netlink messages to that process.
audit: netlink socket can be auto-bound to pid other than current->pid (v2) From: Pavel Emelyanov <xemul@openvz.org> This patch is based on the one from Thomas. The kauditd_thread() calls the netlink_unicast() and passes the audit_pid to it. The audit_pid, in turn, is received from the user space and the tool (I've checked the audit v1.6.9) uses getpid() to pass one in the kernel. Besides, this tool doesn't bind the netlink socket to this id, but simply creates it allowing the kernel to auto-bind one. That's the preamble. The problem is that netlink_autobind() _does_not_ guarantees that the socket will be auto-bound to the current pid. Instead it uses the current pid as a hint to start looking for a free id. So, in case of conflict, the audit messages can be sent to a wrong socket. This can happen (it's unlikely, but can be) in case some task opens more than one netlink sockets and then the audit one starts - in this case the audit's pid can be busy and its socket will be bound to another id. The proposal is to introduce an audit_nlk_pid in audit subsys, that will point to the netlink socket to send packets to. It will most often be equal to audit_pid. The socket id can be got from the skb's netlink CB right in the audit_receive_msg. The audit_nlk_pid reset to 0 is not required, since all the decisions are taken based on audit_pid value only. Later, if the audit tools will bind the socket themselves, the kernel will have to provide a way to setup the audit_nlk_pid as well. A good side effect of this patch is that audit_pid can later be converted to struct pid, as it is not longer safe to use pid_t-s in the presence of pid namespaces. But audit code still uses the tgid from task_struct in the audit_signal_info and in the audit_filter_syscall. Signed-off-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-03-20 23:39:41 +01:00
*/
int audit_pid;
static __u32 audit_nlk_portid;
/* If audit_rate_limit is non-zero, limit the rate of sending audit records
* to that number per second. This prevents DoS attacks, but results in
* audit records being dropped. */
static u32 audit_rate_limit;
/* Number of outstanding audit_buffers allowed.
* When set to zero, this means unlimited. */
static u32 audit_backlog_limit = 64;
#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
/* The identity of the user shutting down the audit system. */
kuid_t audit_sig_uid = INVALID_UID;
pid_t audit_sig_pid = -1;
u32 audit_sig_sid = 0;
/* Records can be lost in several ways:
0) [suppressed in audit_alloc]
1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
2) out of memory in audit_log_move [alloc_skb]
3) suppressed due to audit_rate_limit
4) suppressed due to audit_backlog_limit
*/
static atomic_t audit_lost = ATOMIC_INIT(0);
/* The netlink socket. */
static struct sock *audit_sock;
netns: make struct pernet_operations::id unsigned int Make struct pernet_operations::id unsigned. There are 2 reasons to do so: 1) This field is really an index into an zero based array and thus is unsigned entity. Using negative value is out-of-bound access by definition. 2) On x86_64 unsigned 32-bit data which are mixed with pointers via array indexing or offsets added or subtracted to pointers are preffered to signed 32-bit data. "int" being used as an array index needs to be sign-extended to 64-bit before being used. void f(long *p, int i) { g(p[i]); } roughly translates to movsx rsi, esi mov rdi, [rsi+...] call g MOVSX is 3 byte instruction which isn't necessary if the variable is unsigned because x86_64 is zero extending by default. Now, there is net_generic() function which, you guessed it right, uses "int" as an array index: static inline void *net_generic(const struct net *net, int id) { ... ptr = ng->ptr[id - 1]; ... } And this function is used a lot, so those sign extensions add up. Patch snipes ~1730 bytes on allyesconfig kernel (without all junk messing with code generation): add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730) Unfortunately some functions actually grow bigger. This is a semmingly random artefact of code generation with register allocator being used differently. gcc decides that some variable needs to live in new r8+ registers and every access now requires REX prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be used which is longer than [r8] However, overall balance is in negative direction: add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730) function old new delta nfsd4_lock 3886 3959 +73 tipc_link_build_proto_msg 1096 1140 +44 mac80211_hwsim_new_radio 2776 2808 +32 tipc_mon_rcv 1032 1058 +26 svcauth_gss_legacy_init 1413 1429 +16 tipc_bcbase_select_primary 379 392 +13 nfsd4_exchange_id 1247 1260 +13 nfsd4_setclientid_confirm 782 793 +11 ... put_client_renew_locked 494 480 -14 ip_set_sockfn_get 730 716 -14 geneve_sock_add 829 813 -16 nfsd4_sequence_done 721 703 -18 nlmclnt_lookup_host 708 686 -22 nfsd4_lockt 1085 1063 -22 nfs_get_client 1077 1050 -27 tcf_bpf_init 1106 1076 -30 nfsd4_encode_fattr 5997 5930 -67 Total: Before=154856051, After=154854321, chg -0.00% Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-17 02:58:21 +01:00
static unsigned int audit_net_id;
/* Hash for inode-based rules */
struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
/* The audit_freelist is a list of pre-allocated audit buffers (if more
* than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
* being placed on the freelist). */
static DEFINE_SPINLOCK(audit_freelist_lock);
static int audit_freelist_count;
static LIST_HEAD(audit_freelist);
/* queue msgs to send via kauditd_task */
static struct sk_buff_head audit_queue;
/* queue msgs due to temporary unicast send problems */
static struct sk_buff_head audit_retry_queue;
/* queue msgs waiting for new auditd connection */
static struct sk_buff_head audit_hold_queue;
/* queue servicing thread */
static struct task_struct *kauditd_task;
static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
/* waitqueue for callers who are blocked on the audit backlog */
static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
.mask = -1,
.features = 0,
.lock = 0,};
static char *audit_feature_names[2] = {
"only_unset_loginuid",
"loginuid_immutable",
};
/* Serialize requests from userspace. */
DEFINE_MUTEX(audit_cmd_mutex);
/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
* audit records. Since printk uses a 1024 byte buffer, this buffer
* should be at least that large. */
#define AUDIT_BUFSIZ 1024
/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
* audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
#define AUDIT_MAXFREE (2*NR_CPUS)
/* The audit_buffer is used when formatting an audit record. The caller
* locks briefly to get the record off the freelist or to allocate the
* buffer, and locks briefly to send the buffer to the netlink layer or
* to place it on a transmit queue. Multiple audit_buffers can be in
* use simultaneously. */
struct audit_buffer {
struct list_head list;
struct sk_buff *skb; /* formatted skb ready to send */
struct audit_context *ctx; /* NULL or associated context */
gfp_t gfp_mask;
};
struct audit_reply {
__u32 portid;
struct net *net;
struct sk_buff *skb;
};
static void audit_set_portid(struct audit_buffer *ab, __u32 portid)
{
if (ab) {
struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
nlh->nlmsg_pid = portid;
}
}
void audit_panic(const char *message)
{
switch (audit_failure) {
case AUDIT_FAIL_SILENT:
break;
case AUDIT_FAIL_PRINTK:
if (printk_ratelimit())
pr_err("%s\n", message);
break;
case AUDIT_FAIL_PANIC:
/* test audit_pid since printk is always losey, why bother? */
if (audit_pid)
panic("audit: %s\n", message);
break;
}
}
static inline int audit_rate_check(void)
{
static unsigned long last_check = 0;
static int messages = 0;
static DEFINE_SPINLOCK(lock);
unsigned long flags;
unsigned long now;
unsigned long elapsed;
int retval = 0;
if (!audit_rate_limit) return 1;
spin_lock_irqsave(&lock, flags);
if (++messages < audit_rate_limit) {
retval = 1;
} else {
now = jiffies;
elapsed = now - last_check;
if (elapsed > HZ) {
last_check = now;
messages = 0;
retval = 1;
}
}
spin_unlock_irqrestore(&lock, flags);
return retval;
}
/**
* audit_log_lost - conditionally log lost audit message event
* @message: the message stating reason for lost audit message
*
* Emit at least 1 message per second, even if audit_rate_check is
* throttling.
* Always increment the lost messages counter.
*/
void audit_log_lost(const char *message)
{
static unsigned long last_msg = 0;
static DEFINE_SPINLOCK(lock);
unsigned long flags;
unsigned long now;
int print;
atomic_inc(&audit_lost);
print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
if (!print) {
spin_lock_irqsave(&lock, flags);
now = jiffies;
if (now - last_msg > HZ) {
print = 1;
last_msg = now;
}
spin_unlock_irqrestore(&lock, flags);
}
if (print) {
if (printk_ratelimit())
pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
atomic_read(&audit_lost),
audit_rate_limit,
audit_backlog_limit);
audit_panic(message);
}
}
static int audit_log_config_change(char *function_name, u32 new, u32 old,
int allow_changes)
{
struct audit_buffer *ab;
int rc = 0;
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
if (unlikely(!ab))
return rc;
audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
2013-04-30 15:53:34 +02:00
audit_log_session_info(ab);
rc = audit_log_task_context(ab);
if (rc)
allow_changes = 0; /* Something weird, deny request */
audit_log_format(ab, " res=%d", allow_changes);
audit_log_end(ab);
return rc;
}
static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
{
int allow_changes, rc = 0;
u32 old = *to_change;
/* check if we are locked */
if (audit_enabled == AUDIT_LOCKED)
allow_changes = 0;
else
allow_changes = 1;
if (audit_enabled != AUDIT_OFF) {
rc = audit_log_config_change(function_name, new, old, allow_changes);
if (rc)
allow_changes = 0;
}
/* If we are allowed, make the change */
if (allow_changes == 1)
*to_change = new;
/* Not allowed, update reason */
else if (rc == 0)
rc = -EPERM;
return rc;
}
static int audit_set_rate_limit(u32 limit)
{
return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
}
static int audit_set_backlog_limit(u32 limit)
{
return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
}
static int audit_set_backlog_wait_time(u32 timeout)
{
return audit_do_config_change("audit_backlog_wait_time",
&audit_backlog_wait_time, timeout);
}
static int audit_set_enabled(u32 state)
{
int rc;
if (state > AUDIT_LOCKED)
return -EINVAL;
rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
if (!rc)
audit_ever_enabled |= !!state;
return rc;
}
static int audit_set_failure(u32 state)
{
if (state != AUDIT_FAIL_SILENT
&& state != AUDIT_FAIL_PRINTK
&& state != AUDIT_FAIL_PANIC)
return -EINVAL;
return audit_do_config_change("audit_failure", &audit_failure, state);
}
/*
* For one reason or another this nlh isn't getting delivered to the userspace
* audit daemon, just send it to printk.
*/
static void kauditd_printk_skb(struct sk_buff *skb)
{
struct nlmsghdr *nlh = nlmsg_hdr(skb);
char *data = nlmsg_data(nlh);
if (nlh->nlmsg_type != AUDIT_EOE) {
if (printk_ratelimit())
pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
else
audit_log_lost("printk limit exceeded");
}
}
/**
* kauditd_hold_skb - Queue an audit record, waiting for auditd
* @skb: audit record
*
* Description:
* Queue the audit record, waiting for an instance of auditd. When this
* function is called we haven't given up yet on sending the record, but things
* are not looking good. The first thing we want to do is try to write the
* record via printk and then see if we want to try and hold on to the record
* and queue it, if we have room. If we want to hold on to the record, but we
* don't have room, record a record lost message.
*/
static void kauditd_hold_skb(struct sk_buff *skb)
{
/* at this point it is uncertain if we will ever send this to auditd so
* try to send the message via printk before we go any further */
kauditd_printk_skb(skb);
/* can we just silently drop the message? */
if (!audit_default) {
kfree_skb(skb);
return;
}
/* if we have room, queue the message */
if (!audit_backlog_limit ||
skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
skb_queue_tail(&audit_hold_queue, skb);
return;
}
/* we have no other options - drop the message */
audit_log_lost("kauditd hold queue overflow");
kfree_skb(skb);
}
/**
* kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
* @skb: audit record
*
* Description:
* Not as serious as kauditd_hold_skb() as we still have a connected auditd,
* but for some reason we are having problems sending it audit records so
* queue the given record and attempt to resend.
*/
static void kauditd_retry_skb(struct sk_buff *skb)
{
/* NOTE: because records should only live in the retry queue for a
* short period of time, before either being sent or moved to the hold
* queue, we don't currently enforce a limit on this queue */
skb_queue_tail(&audit_retry_queue, skb);
}
audit: try harder to send to auditd upon netlink failure There are several reports of the kernel losing contact with auditd when it is, in fact, still running. When this happens, kernel syslogs show: "audit: *NO* daemon at audit_pid=<pid>" although auditd is still running, and is apparently happy, listening on the netlink socket. The pid in the "*NO* daemon" message matches the pid of the running auditd process. Restarting auditd solves this. The problem appears to happen randomly, and doesn't seem to be strongly correlated to the rate of audit events being logged. The problem happens fairly regularly (every few days), but not yet reproduced to order. On production kernels, BUG_ON() is a no-op, so any error will trigger this. Commit 34eab0a7cd45 ("audit: prevent an older auditd shutdown from orphaning a newer auditd startup") eliminates one possible cause. This isn't the case here, since the PID in the error message and the PID of the running auditd match. The primary expected cause of error here is -ECONNREFUSED when the audit daemon goes away, when netlink_getsockbyportid() can't find the auditd portid entry in the netlink audit table (or there is no receive function). If -EPERM is returned, that situation isn't likely to be resolved in a timely fashion without administrator intervention. In both cases, reset the audit_pid. This does not rule out a race condition. SELinux is expected to return zero since this isn't an INET or INET6 socket. Other LSMs may have other return codes. Log the error code for better diagnosis in the future. In the case of -ENOMEM, the situation could be temporary, based on local or general availability of buffers. -EAGAIN should never happen since the netlink audit (kernel) socket is set to MAX_SCHEDULE_TIMEOUT. -ERESTARTSYS and -EINTR are not expected since this kernel thread is not expected to receive signals. In these cases (or any other unexpected ones for now), report the error and re-schedule the thread, retrying up to 5 times. v2: Removed BUG_ON(). Moved comma in pr_*() statements. Removed audit_strerror() text. Reported-by: Vipin Rathor <v.rathor@gmail.com> Reported-by: <ctcard@hotmail.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> [PM: applied rgb's fixup patch to correct audit_log_lost() format issues] Signed-off-by: Paul Moore <pmoore@redhat.com>
2015-11-04 14:23:50 +01:00
/**
* auditd_reset - Disconnect the auditd connection
*
* Description:
* Break the auditd/kauditd connection and move all the records in the retry
* queue into the hold queue in case auditd reconnects. The audit_cmd_mutex
* must be held when calling this function.
*/
static void auditd_reset(void)
{
struct sk_buff *skb;
/* break the connection */
if (audit_sock) {
sock_put(audit_sock);
audit_sock = NULL;
}
audit_pid = 0;
audit_nlk_portid = 0;
/* flush all of the retry queue to the hold queue */
while ((skb = skb_dequeue(&audit_retry_queue)))
kauditd_hold_skb(skb);
}
/**
* kauditd_send_unicast_skb - Send a record via unicast to auditd
* @skb: audit record
*/
static int kauditd_send_unicast_skb(struct sk_buff *skb)
{
int rc;
audit: try harder to send to auditd upon netlink failure There are several reports of the kernel losing contact with auditd when it is, in fact, still running. When this happens, kernel syslogs show: "audit: *NO* daemon at audit_pid=<pid>" although auditd is still running, and is apparently happy, listening on the netlink socket. The pid in the "*NO* daemon" message matches the pid of the running auditd process. Restarting auditd solves this. The problem appears to happen randomly, and doesn't seem to be strongly correlated to the rate of audit events being logged. The problem happens fairly regularly (every few days), but not yet reproduced to order. On production kernels, BUG_ON() is a no-op, so any error will trigger this. Commit 34eab0a7cd45 ("audit: prevent an older auditd shutdown from orphaning a newer auditd startup") eliminates one possible cause. This isn't the case here, since the PID in the error message and the PID of the running auditd match. The primary expected cause of error here is -ECONNREFUSED when the audit daemon goes away, when netlink_getsockbyportid() can't find the auditd portid entry in the netlink audit table (or there is no receive function). If -EPERM is returned, that situation isn't likely to be resolved in a timely fashion without administrator intervention. In both cases, reset the audit_pid. This does not rule out a race condition. SELinux is expected to return zero since this isn't an INET or INET6 socket. Other LSMs may have other return codes. Log the error code for better diagnosis in the future. In the case of -ENOMEM, the situation could be temporary, based on local or general availability of buffers. -EAGAIN should never happen since the netlink audit (kernel) socket is set to MAX_SCHEDULE_TIMEOUT. -ERESTARTSYS and -EINTR are not expected since this kernel thread is not expected to receive signals. In these cases (or any other unexpected ones for now), report the error and re-schedule the thread, retrying up to 5 times. v2: Removed BUG_ON(). Moved comma in pr_*() statements. Removed audit_strerror() text. Reported-by: Vipin Rathor <v.rathor@gmail.com> Reported-by: <ctcard@hotmail.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> [PM: applied rgb's fixup patch to correct audit_log_lost() format issues] Signed-off-by: Paul Moore <pmoore@redhat.com>
2015-11-04 14:23:50 +01:00
/* if we know nothing is connected, don't even try the netlink call */
if (!audit_pid)
return -ECONNREFUSED;
/* get an extra skb reference in case we fail to send */
skb_get(skb);
rc = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
if (rc >= 0) {
consume_skb(skb);
rc = 0;
}
return rc;
}
/*
* kauditd_send_multicast_skb - Send a record to any multicast listeners
* @skb: audit record
*
* Description:
* This function doesn't consume an skb as might be expected since it has to
* copy it anyways.
*/
static void kauditd_send_multicast_skb(struct sk_buff *skb)
{
struct sk_buff *copy;
struct audit_net *aunet = net_generic(&init_net, audit_net_id);
struct sock *sock = aunet->nlsk;
struct nlmsghdr *nlh;
if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
return;
/*
* The seemingly wasteful skb_copy() rather than bumping the refcount
* using skb_get() is necessary because non-standard mods are made to
* the skb by the original kaudit unicast socket send routine. The
* existing auditd daemon assumes this breakage. Fixing this would
* require co-ordinating a change in the established protocol between
* the kaudit kernel subsystem and the auditd userspace code. There is
* no reason for new multicast clients to continue with this
* non-compliance.
*/
copy = skb_copy(skb, GFP_KERNEL);
if (!copy)
return;
nlh = nlmsg_hdr(copy);
nlh->nlmsg_len = skb->len;
nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
}
/**
* kauditd_wake_condition - Return true when it is time to wake kauditd_thread
*
* Description:
* This function is for use by the wait_event_freezable() call in
* kauditd_thread().
*/
static int kauditd_wake_condition(void)
{
static int pid_last = 0;
int rc;
int pid = audit_pid;
/* wake on new messages or a change in the connected auditd */
rc = skb_queue_len(&audit_queue) || (pid && pid != pid_last);
if (rc)
pid_last = pid;
return rc;
}
static int kauditd_thread(void *dummy)
{
int rc;
int auditd = 0;
int reschedule = 0;
struct sk_buff *skb;
struct nlmsghdr *nlh;
#define UNICAST_RETRIES 5
#define AUDITD_BAD(x,y) \
((x) == -ECONNREFUSED || (x) == -EPERM || ++(y) >= UNICAST_RETRIES)
/* NOTE: we do invalidate the auditd connection flag on any sending
* errors, but we only "restore" the connection flag at specific places
* in the loop in order to help ensure proper ordering of audit
* records */
set_freezable();
while (!kthread_should_stop()) {
/* NOTE: possible area for future improvement is to look at
* the hold and retry queues, since only this thread
* has access to these queues we might be able to do
* our own queuing and skip some/all of the locking */
/* NOTE: it might be a fun experiment to split the hold and
* retry queue handling to another thread, but the
* synchronization issues and other overhead might kill
* any performance gains */
/* attempt to flush the hold queue */
while (auditd && (skb = skb_dequeue(&audit_hold_queue))) {
rc = kauditd_send_unicast_skb(skb);
if (rc) {
/* requeue to the same spot */
skb_queue_head(&audit_hold_queue, skb);
auditd = 0;
if (AUDITD_BAD(rc, reschedule)) {
mutex_lock(&audit_cmd_mutex);
auditd_reset();
mutex_unlock(&audit_cmd_mutex);
reschedule = 0;
}
} else
/* we were able to send successfully */
reschedule = 0;
}
/* attempt to flush the retry queue */
while (auditd && (skb = skb_dequeue(&audit_retry_queue))) {
rc = kauditd_send_unicast_skb(skb);
if (rc) {
auditd = 0;
if (AUDITD_BAD(rc, reschedule)) {
kauditd_hold_skb(skb);
mutex_lock(&audit_cmd_mutex);
auditd_reset();
mutex_unlock(&audit_cmd_mutex);
reschedule = 0;
} else
/* temporary problem (we hope), queue
* to the same spot and retry */
skb_queue_head(&audit_retry_queue, skb);
} else
/* we were able to send successfully */
reschedule = 0;
}
audit: efficiency fix 1: only wake up if queue shorter than backlog limit These and similar errors were seen on a patched 3.8 kernel when the audit subsystem was overrun during boot: udevd[876]: worker [887] unexpectedly returned with status 0x0100 udevd[876]: worker [887] failed while handling '/devices/pci0000:00/0000:00:03.0/0000:40:00.0' udevd[876]: worker [880] unexpectedly returned with status 0x0100 udevd[876]: worker [880] failed while handling '/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1' udevadm settle - timeout of 180 seconds reached, the event queue contains: /sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input1/event1 (3995) /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/INT3F0D:00 (4034) audit: audit_backlog=258 > audit_backlog_limit=256 audit: audit_lost=1 audit_rate_limit=0 audit_backlog_limit=256 The change below increases the efficiency of the audit code and prevents it from being overrun: Only issue a wake_up in kauditd if the length of the skb queue is less than the backlog limit. Otherwise, threads waiting in wait_for_auditd() will simply wake up, discover that the queue is still too long for them to proceed, and go back to sleep. This results in wasted context switches and machine cycles. kauditd_thread() is the only function that removes buffers from audit_skb_queue so we can't race. If we did, the timeout in wait_for_auditd() would expire and the waiting thread would continue. See: https://lkml.org/lkml/2013/9/2/479 Signed-off-by: Dan Duval <dan.duval@oracle.com> Signed-off-by: Chuck Anderson <chuck.anderson@oracle.com> Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2013-09-16 17:11:12 +02:00
/* standard queue processing, try to be as quick as possible */
quick_loop:
skb = skb_dequeue(&audit_queue);
if (skb) {
/* setup the netlink header, see the comments in
* kauditd_send_multicast_skb() for length quirks */
nlh = nlmsg_hdr(skb);
nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
/* attempt to send to any multicast listeners */
kauditd_send_multicast_skb(skb);
/* attempt to send to auditd, queue on failure */
if (auditd) {
rc = kauditd_send_unicast_skb(skb);
if (rc) {
auditd = 0;
if (AUDITD_BAD(rc, reschedule)) {
mutex_lock(&audit_cmd_mutex);
auditd_reset();
mutex_unlock(&audit_cmd_mutex);
reschedule = 0;
}
/* move to the retry queue */
kauditd_retry_skb(skb);
} else
/* everything is working so go fast! */
goto quick_loop;
} else if (reschedule)
/* we are currently having problems, move to
* the retry queue */
kauditd_retry_skb(skb);
else
/* dump the message via printk and hold it */
kauditd_hold_skb(skb);
} else {
/* we have flushed the backlog so wake everyone */
wake_up(&audit_backlog_wait);
/* if everything is okay with auditd (if present), go
* to sleep until there is something new in the queue
* or we have a change in the connected auditd;
* otherwise simply reschedule to give things a chance
* to recover */
if (reschedule) {
set_current_state(TASK_INTERRUPTIBLE);
schedule();
} else
wait_event_freezable(kauditd_wait,
kauditd_wake_condition());
/* update the auditd connection status */
auditd = (audit_pid ? 1 : 0);
}
}
return 0;
}
int audit_send_list(void *_dest)
{
struct audit_netlink_list *dest = _dest;
struct sk_buff *skb;
struct net *net = dest->net;
struct audit_net *aunet = net_generic(net, audit_net_id);
/* wait for parent to finish and send an ACK */
mutex_lock(&audit_cmd_mutex);
mutex_unlock(&audit_cmd_mutex);
while ((skb = __skb_dequeue(&dest->q)) != NULL)
netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
put_net(net);
kfree(dest);
return 0;
}
struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
int multi, const void *payload, int size)
{
struct sk_buff *skb;
struct nlmsghdr *nlh;
void *data;
int flags = multi ? NLM_F_MULTI : 0;
int t = done ? NLMSG_DONE : type;
skb = nlmsg_new(size, GFP_KERNEL);
if (!skb)
return NULL;
nlh = nlmsg_put(skb, portid, seq, t, size, flags);
if (!nlh)
goto out_kfree_skb;
data = nlmsg_data(nlh);
memcpy(data, payload, size);
return skb;
out_kfree_skb:
kfree_skb(skb);
return NULL;
}
static int audit_send_reply_thread(void *arg)
{
struct audit_reply *reply = (struct audit_reply *)arg;
struct net *net = reply->net;
struct audit_net *aunet = net_generic(net, audit_net_id);
mutex_lock(&audit_cmd_mutex);
mutex_unlock(&audit_cmd_mutex);
/* Ignore failure. It'll only happen if the sender goes away,
because our timeout is set to infinite. */
netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
put_net(net);
kfree(reply);
return 0;
}
/**
* audit_send_reply - send an audit reply message via netlink
* @request_skb: skb of request we are replying to (used to target the reply)
* @seq: sequence number
* @type: audit message type
* @done: done (last) flag
* @multi: multi-part message flag
* @payload: payload data
* @size: payload size
*
* Allocates an skb, builds the netlink message, and sends it to the port id.
* No failure notifications.
*/
static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
int multi, const void *payload, int size)
{
u32 portid = NETLINK_CB(request_skb).portid;
struct net *net = sock_net(NETLINK_CB(request_skb).sk);
struct sk_buff *skb;
struct task_struct *tsk;
struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
GFP_KERNEL);
if (!reply)
return;
skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
if (!skb)
goto out;
reply->net = get_net(net);
reply->portid = portid;
reply->skb = skb;
tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
if (!IS_ERR(tsk))
return;
kfree_skb(skb);
out:
kfree(reply);
}
/*
* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
* control messages.
*/
static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
{
int err = 0;
/* Only support initial user namespace for now. */
AUDIT: Allow login in non-init namespaces It its possible to configure your PAM stack to refuse login if audit messages (about the login) were unable to be sent. This is common in many distros and thus normal configuration of many containers. The PAM modules determine if audit is enabled/disabled in the kernel based on the return value from sending an audit message on the netlink socket. If userspace gets back ECONNREFUSED it believes audit is disabled in the kernel. If it gets any other error else it refuses to let the login proceed. Just about ever since the introduction of namespaces the kernel audit subsystem has returned EPERM if the task sending a message was not in the init user or pid namespace. So many forms of containers have never worked if audit was enabled in the kernel. BUT if the container was not in net_init then the kernel network code would send ECONNREFUSED (instead of the audit code sending EPERM). Thus by pure accident/dumb luck/bug if an admin configured the PAM stack to reject all logins that didn't talk to audit, but then ran the login untility in the non-init_net namespace, it would work!! Clearly this was a bug, but it is a bug some people expected. With the introduction of network namespace support in 3.14-rc1 the two bugs stopped cancelling each other out. Now, containers in the non-init_net namespace refused to let users log in (just like PAM was configfured!) Obviously some people were not happy that what used to let users log in, now didn't! This fix is kinda hacky. We return ECONNREFUSED for all non-init relevant namespaces. That means that not only will the old broken non-init_net setups continue to work, now the broken non-init_pid or non-init_user setups will 'work'. They don't really work, since audit isn't logging things. But it's what most users want. In 3.15 we should have patches to support not only the non-init_net (3.14) namespace but also the non-init_pid and non-init_user namespace. So all will be right in the world. This just opens the doors wide open on 3.14 and hopefully makes users happy, if not the audit system... Reported-by: Andre Tomt <andre@tomt.net> Reported-by: Adam Richter <adam_richter2004@yahoo.com> Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-31 01:07:54 +02:00
/*
* We return ECONNREFUSED because it tricks userspace into thinking
* that audit was not configured into the kernel. Lots of users
* configure their PAM stack (because that's what the distro does)
* to reject login if unable to send messages to audit. If we return
* ECONNREFUSED the PAM stack thinks the kernel does not have audit
* configured in and will let login proceed. If we return EPERM
* userspace will reject all logins. This should be removed when we
* support non init namespaces!!
*/
if (current_user_ns() != &init_user_ns)
AUDIT: Allow login in non-init namespaces It its possible to configure your PAM stack to refuse login if audit messages (about the login) were unable to be sent. This is common in many distros and thus normal configuration of many containers. The PAM modules determine if audit is enabled/disabled in the kernel based on the return value from sending an audit message on the netlink socket. If userspace gets back ECONNREFUSED it believes audit is disabled in the kernel. If it gets any other error else it refuses to let the login proceed. Just about ever since the introduction of namespaces the kernel audit subsystem has returned EPERM if the task sending a message was not in the init user or pid namespace. So many forms of containers have never worked if audit was enabled in the kernel. BUT if the container was not in net_init then the kernel network code would send ECONNREFUSED (instead of the audit code sending EPERM). Thus by pure accident/dumb luck/bug if an admin configured the PAM stack to reject all logins that didn't talk to audit, but then ran the login untility in the non-init_net namespace, it would work!! Clearly this was a bug, but it is a bug some people expected. With the introduction of network namespace support in 3.14-rc1 the two bugs stopped cancelling each other out. Now, containers in the non-init_net namespace refused to let users log in (just like PAM was configfured!) Obviously some people were not happy that what used to let users log in, now didn't! This fix is kinda hacky. We return ECONNREFUSED for all non-init relevant namespaces. That means that not only will the old broken non-init_net setups continue to work, now the broken non-init_pid or non-init_user setups will 'work'. They don't really work, since audit isn't logging things. But it's what most users want. In 3.15 we should have patches to support not only the non-init_net (3.14) namespace but also the non-init_pid and non-init_user namespace. So all will be right in the world. This just opens the doors wide open on 3.14 and hopefully makes users happy, if not the audit system... Reported-by: Andre Tomt <andre@tomt.net> Reported-by: Adam Richter <adam_richter2004@yahoo.com> Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-31 01:07:54 +02:00
return -ECONNREFUSED;
switch (msg_type) {
case AUDIT_LIST:
case AUDIT_ADD:
case AUDIT_DEL:
return -EOPNOTSUPP;
case AUDIT_GET:
case AUDIT_SET:
case AUDIT_GET_FEATURE:
case AUDIT_SET_FEATURE:
case AUDIT_LIST_RULES:
case AUDIT_ADD_RULE:
case AUDIT_DEL_RULE:
case AUDIT_SIGNAL_INFO:
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
case AUDIT_TTY_GET:
case AUDIT_TTY_SET:
case AUDIT_TRIM:
case AUDIT_MAKE_EQUIV:
/* Only support auditd and auditctl in initial pid namespace
* for now. */
if (task_active_pid_ns(current) != &init_pid_ns)
return -EPERM;
if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
err = -EPERM;
break;
case AUDIT_USER:
case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
if (!netlink_capable(skb, CAP_AUDIT_WRITE))
err = -EPERM;
break;
default: /* bad msg */
err = -EINVAL;
}
return err;
}
static void audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
{
uid_t uid = from_kuid(&init_user_ns, current_uid());
pid_t pid = task_tgid_nr(current);
if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
*ab = NULL;
return;
}
*ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
if (unlikely(!*ab))
return;
audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
2013-04-30 15:53:34 +02:00
audit_log_session_info(*ab);
audit_log_task_context(*ab);
}
int is_audit_feature_set(int i)
{
return af.features & AUDIT_FEATURE_TO_MASK(i);
}
static int audit_get_feature(struct sk_buff *skb)
{
u32 seq;
seq = nlmsg_hdr(skb)->nlmsg_seq;
audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
return 0;
}
static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
u32 old_lock, u32 new_lock, int res)
{
struct audit_buffer *ab;
if (audit_enabled == AUDIT_OFF)
return;
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
audit_log_task_info(ab, current);
audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
audit_feature_names[which], !!old_feature, !!new_feature,
!!old_lock, !!new_lock, res);
audit_log_end(ab);
}
static int audit_set_feature(struct sk_buff *skb)
{
struct audit_features *uaf;
int i;
BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
uaf = nlmsg_data(nlmsg_hdr(skb));
/* if there is ever a version 2 we should handle that here */
for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
u32 feature = AUDIT_FEATURE_TO_MASK(i);
u32 old_feature, new_feature, old_lock, new_lock;
/* if we are not changing this feature, move along */
if (!(feature & uaf->mask))
continue;
old_feature = af.features & feature;
new_feature = uaf->features & feature;
new_lock = (uaf->lock | af.lock) & feature;
old_lock = af.lock & feature;
/* are we changing a locked feature? */
if (old_lock && (new_feature != old_feature)) {
audit_log_feature_change(i, old_feature, new_feature,
old_lock, new_lock, 0);
return -EPERM;
}
}
/* nothing invalid, do the changes */
for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
u32 feature = AUDIT_FEATURE_TO_MASK(i);
u32 old_feature, new_feature, old_lock, new_lock;
/* if we are not changing this feature, move along */
if (!(feature & uaf->mask))
continue;
old_feature = af.features & feature;
new_feature = uaf->features & feature;
old_lock = af.lock & feature;
new_lock = (uaf->lock | af.lock) & feature;
if (new_feature != old_feature)
audit_log_feature_change(i, old_feature, new_feature,
old_lock, new_lock, 1);
if (new_feature)
af.features |= feature;
else
af.features &= ~feature;
af.lock |= new_lock;
}
return 0;
}
static int audit_replace(pid_t pid)
{
struct sk_buff *skb = audit_make_reply(0, 0, AUDIT_REPLACE, 0, 0,
&pid, sizeof(pid));
if (!skb)
return -ENOMEM;
return netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
}
static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
{
u32 seq;
void *data;
int err;
struct audit_buffer *ab;
u16 msg_type = nlh->nlmsg_type;
struct audit_sig_info *sig_data;
char *ctx = NULL;
u32 len;
err = audit_netlink_ok(skb, msg_type);
if (err)
return err;
seq = nlh->nlmsg_seq;
data = nlmsg_data(nlh);
switch (msg_type) {
case AUDIT_GET: {
struct audit_status s;
memset(&s, 0, sizeof(s));
s.enabled = audit_enabled;
s.failure = audit_failure;
s.pid = audit_pid;
s.rate_limit = audit_rate_limit;
s.backlog_limit = audit_backlog_limit;
s.lost = atomic_read(&audit_lost);
s.backlog = skb_queue_len(&audit_queue);
s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
s.backlog_wait_time = audit_backlog_wait_time;
audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
break;
}
case AUDIT_SET: {
struct audit_status s;
memset(&s, 0, sizeof(s));
/* guard against past and future API changes */
memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
if (s.mask & AUDIT_STATUS_ENABLED) {
err = audit_set_enabled(s.enabled);
if (err < 0)
return err;
}
if (s.mask & AUDIT_STATUS_FAILURE) {
err = audit_set_failure(s.failure);
if (err < 0)
return err;
}
if (s.mask & AUDIT_STATUS_PID) {
/* NOTE: we are using task_tgid_vnr() below because
* the s.pid value is relative to the namespace
* of the caller; at present this doesn't matter
* much since you can really only run auditd
* from the initial pid namespace, but something
* to keep in mind if this changes */
int new_pid = s.pid;
pid_t requesting_pid = task_tgid_vnr(current);
if ((!new_pid) && (requesting_pid != audit_pid)) {
audit_log_config_change("audit_pid", new_pid, audit_pid, 0);
return -EACCES;
}
if (audit_pid && new_pid &&
audit_replace(requesting_pid) != -ECONNREFUSED) {
audit_log_config_change("audit_pid", new_pid, audit_pid, 0);
return -EEXIST;
}
if (audit_enabled != AUDIT_OFF)
audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
if (new_pid) {
if (audit_sock)
sock_put(audit_sock);
audit_pid = new_pid;
audit_nlk_portid = NETLINK_CB(skb).portid;
sock_hold(skb->sk);
audit_sock = skb->sk;
} else {
auditd_reset();
}
wake_up_interruptible(&kauditd_wait);
}
if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
err = audit_set_rate_limit(s.rate_limit);
if (err < 0)
return err;
}
if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
err = audit_set_backlog_limit(s.backlog_limit);
if (err < 0)
return err;
}
if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
if (sizeof(s) > (size_t)nlh->nlmsg_len)
return -EINVAL;
if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
return -EINVAL;
err = audit_set_backlog_wait_time(s.backlog_wait_time);
if (err < 0)
return err;
}
if (s.mask == AUDIT_STATUS_LOST) {
u32 lost = atomic_xchg(&audit_lost, 0);
audit_log_config_change("lost", 0, lost, 1);
return lost;
}
break;
}
case AUDIT_GET_FEATURE:
err = audit_get_feature(skb);
if (err)
return err;
break;
case AUDIT_SET_FEATURE:
err = audit_set_feature(skb);
if (err)
return err;
break;
case AUDIT_USER:
case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
if (!audit_enabled && msg_type != AUDIT_USER_AVC)
return 0;
err = audit_filter(msg_type, AUDIT_FILTER_USER);
if (err == 1) { /* match or error */
err = 0;
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
if (msg_type == AUDIT_USER_TTY) {
err = tty_audit_push();
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
if (err)
break;
}
mutex_unlock(&audit_cmd_mutex);
audit_log_common_recv_msg(&ab, msg_type);
if (msg_type != AUDIT_USER_TTY)
audit_log_format(ab, " msg='%.*s'",
AUDIT_MESSAGE_TEXT_MAX,
(char *)data);
else {
int size;
audit_log_format(ab, " data=");
size = nlmsg_len(nlh);
if (size > 0 &&
((unsigned char *)data)[size - 1] == '\0')
size--;
audit_log_n_untrustedstring(ab, data, size);
}
audit_set_portid(ab, NETLINK_CB(skb).portid);
audit_log_end(ab);
mutex_lock(&audit_cmd_mutex);
}
break;
case AUDIT_ADD_RULE:
case AUDIT_DEL_RULE:
if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
return -EINVAL;
if (audit_enabled == AUDIT_LOCKED) {
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
audit_log_end(ab);
return -EPERM;
}
err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
seq, data, nlmsg_len(nlh));
break;
case AUDIT_LIST_RULES:
err = audit_list_rules_send(skb, seq);
break;
case AUDIT_TRIM:
audit_trim_trees();
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
audit_log_format(ab, " op=trim res=1");
audit_log_end(ab);
break;
case AUDIT_MAKE_EQUIV: {
void *bufp = data;
u32 sizes[2];
size_t msglen = nlmsg_len(nlh);
char *old, *new;
err = -EINVAL;
if (msglen < 2 * sizeof(u32))
break;
memcpy(sizes, bufp, 2 * sizeof(u32));
bufp += 2 * sizeof(u32);
msglen -= 2 * sizeof(u32);
old = audit_unpack_string(&bufp, &msglen, sizes[0]);
if (IS_ERR(old)) {
err = PTR_ERR(old);
break;
}
new = audit_unpack_string(&bufp, &msglen, sizes[1]);
if (IS_ERR(new)) {
err = PTR_ERR(new);
kfree(old);
break;
}
/* OK, here comes... */
err = audit_tag_tree(old, new);
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
audit_log_format(ab, " op=make_equiv old=");
audit_log_untrustedstring(ab, old);
audit_log_format(ab, " new=");
audit_log_untrustedstring(ab, new);
audit_log_format(ab, " res=%d", !err);
audit_log_end(ab);
kfree(old);
kfree(new);
break;
}
case AUDIT_SIGNAL_INFO:
len = 0;
if (audit_sig_sid) {
err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
if (err)
return err;
}
sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
if (!sig_data) {
if (audit_sig_sid)
security_release_secctx(ctx, len);
return -ENOMEM;
}
sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
sig_data->pid = audit_sig_pid;
if (audit_sig_sid) {
memcpy(sig_data->ctx, ctx, len);
security_release_secctx(ctx, len);
}
audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
sig_data, sizeof(*sig_data) + len);
kfree(sig_data);
break;
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
case AUDIT_TTY_GET: {
struct audit_tty_status s;
unsigned int t;
t = READ_ONCE(current->signal->audit_tty);
s.enabled = t & AUDIT_TTY_ENABLE;
s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
break;
}
case AUDIT_TTY_SET: {
struct audit_tty_status s, old;
struct audit_buffer *ab;
unsigned int t;
memset(&s, 0, sizeof(s));
/* guard against past and future API changes */
memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
/* check if new data is valid */
if ((s.enabled != 0 && s.enabled != 1) ||
(s.log_passwd != 0 && s.log_passwd != 1))
err = -EINVAL;
if (err)
t = READ_ONCE(current->signal->audit_tty);
else {
t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
t = xchg(&current->signal->audit_tty, t);
}
old.enabled = t & AUDIT_TTY_ENABLE;
old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
" old-log_passwd=%d new-log_passwd=%d res=%d",
old.enabled, s.enabled, old.log_passwd,
s.log_passwd, !err);
audit_log_end(ab);
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
break;
}
default:
err = -EINVAL;
break;
}
return err < 0 ? err : 0;
}
/*
* Get message from skb. Each message is processed by audit_receive_msg.
* Malformed skbs with wrong length are discarded silently.
*/
[NETLINK]: Synchronous message processing. Let's recap the problem. The current asynchronous netlink kernel message processing is vulnerable to these attacks: 1) Hit and run: Attacker sends one or more messages and then exits before they're processed. This may confuse/disable the next netlink user that gets the netlink address of the attacker since it may receive the responses to the attacker's messages. Proposed solutions: a) Synchronous processing. b) Stream mode socket. c) Restrict/prohibit binding. 2) Starvation: Because various netlink rcv functions were written to not return until all messages have been processed on a socket, it is possible for these functions to execute for an arbitrarily long period of time. If this is successfully exploited it could also be used to hold rtnl forever. Proposed solutions: a) Synchronous processing. b) Stream mode socket. Firstly let's cross off solution c). It only solves the first problem and it has user-visible impacts. In particular, it'll break user space applications that expect to bind or communicate with specific netlink addresses (pid's). So we're left with a choice of synchronous processing versus SOCK_STREAM for netlink. For the moment I'm sticking with the synchronous approach as suggested by Alexey since it's simpler and I'd rather spend my time working on other things. However, it does have a number of deficiencies compared to the stream mode solution: 1) User-space to user-space netlink communication is still vulnerable. 2) Inefficient use of resources. This is especially true for rtnetlink since the lock is shared with other users such as networking drivers. The latter could hold the rtnl while communicating with hardware which causes the rtnetlink user to wait when it could be doing other things. 3) It is still possible to DoS all netlink users by flooding the kernel netlink receive queue. The attacker simply fills the receive socket with a single netlink message that fills up the entire queue. The attacker then continues to call sendmsg with the same message in a loop. Point 3) can be countered by retransmissions in user-space code, however it is pretty messy. In light of these problems (in particular, point 3), we should implement stream mode netlink at some point. In the mean time, here is a patch that implements synchronous processing. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
2005-05-03 23:55:09 +02:00
static void audit_receive_skb(struct sk_buff *skb)
{
struct nlmsghdr *nlh;
/*
* len MUST be signed for nlmsg_next to be able to dec it below 0
* if the nlmsg_len was not aligned
*/
int len;
int err;
nlh = nlmsg_hdr(skb);
len = skb->len;
while (nlmsg_ok(nlh, len)) {
err = audit_receive_msg(skb, nlh);
/* if err or if this message says it wants a response */
if (err || (nlh->nlmsg_flags & NLM_F_ACK))
netlink_ack(skb, nlh, err);
nlh = nlmsg_next(nlh, &len);
}
}
/* Receive messages from netlink socket. */
static void audit_receive(struct sk_buff *skb)
{
mutex_lock(&audit_cmd_mutex);
audit_receive_skb(skb);
mutex_unlock(&audit_cmd_mutex);
}
/* Run custom bind function on netlink socket group connect or bind requests. */
static int audit_bind(struct net *net, int group)
{
if (!capable(CAP_AUDIT_READ))
return -EPERM;
return 0;
}
static int __net_init audit_net_init(struct net *net)
{
struct netlink_kernel_cfg cfg = {
.input = audit_receive,
.bind = audit_bind,
.flags = NL_CFG_F_NONROOT_RECV,
.groups = AUDIT_NLGRP_MAX,
};
struct audit_net *aunet = net_generic(net, audit_net_id);
aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
if (aunet->nlsk == NULL) {
audit_panic("cannot initialize netlink socket in namespace");
return -ENOMEM;
}
aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
return 0;
}
static void __net_exit audit_net_exit(struct net *net)
{
struct audit_net *aunet = net_generic(net, audit_net_id);
struct sock *sock = aunet->nlsk;
mutex_lock(&audit_cmd_mutex);
if (sock == audit_sock)
auditd_reset();
mutex_unlock(&audit_cmd_mutex);
netlink_kernel_release(sock);
aunet->nlsk = NULL;
}
static struct pernet_operations audit_net_ops __net_initdata = {
.init = audit_net_init,
.exit = audit_net_exit,
.id = &audit_net_id,
.size = sizeof(struct audit_net),
};
/* Initialize audit support at boot time. */
static int __init audit_init(void)
{
int i;
if (audit_initialized == AUDIT_DISABLED)
return 0;
pr_info("initializing netlink subsys (%s)\n",
audit_default ? "enabled" : "disabled");
register_pernet_subsys(&audit_net_ops);
skb_queue_head_init(&audit_queue);
skb_queue_head_init(&audit_retry_queue);
skb_queue_head_init(&audit_hold_queue);
audit_initialized = AUDIT_INITIALIZED;
audit_enabled = audit_default;
audit_ever_enabled |= !!audit_default;
for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
INIT_LIST_HEAD(&audit_inode_hash[i]);
kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
if (IS_ERR(kauditd_task)) {
int err = PTR_ERR(kauditd_task);
panic("audit: failed to start the kauditd thread (%d)\n", err);
}
audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
"state=initialized audit_enabled=%u res=1",
audit_enabled);
return 0;
}
__initcall(audit_init);
/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
static int __init audit_enable(char *str)
{
audit_default = !!simple_strtol(str, NULL, 0);
if (!audit_default)
audit_initialized = AUDIT_DISABLED;
pr_info("%s\n", audit_default ?
"enabled (after initialization)" : "disabled (until reboot)");
return 1;
}
__setup("audit=", audit_enable);
audit: add kernel set-up parameter to override default backlog limit The default audit_backlog_limit is 64. This was a reasonable limit at one time. systemd causes so much audit queue activity on startup that auditd doesn't start before the backlog queue has already overflowed by more than a factor of 2. On a system with audit= not set on the kernel command line, this isn't an issue since that history isn't kept for auditd when it is available. On a system with audit=1 set on the kernel command line, kaudit tries to keep that history until auditd is able to drain the queue. This default can be changed by the "-b" option in audit.rules once the system has booted, but won't help with lost messages on boot. One way to solve this would be to increase the default backlog queue size to avoid losing any messages before auditd is able to consume them. This would be overkill to the embedded community and insufficient for some servers. Another way to solve it might be to add a kconfig option to set the default based on the system type. An embedded system would get the current (or smaller) default, while Workstations might get more than now and servers might get more. None of these solutions helps if a system's compiled default is too small to see the lost messages without compiling a new kernel. This patch adds a kernel set-up parameter (audit already has one to enable/disable it) "audit_backlog_limit=<n>" that overrides the default to allow the system administrator to set the backlog limit. Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2013-09-17 18:34:52 +02:00
/* Process kernel command-line parameter at boot time.
* audit_backlog_limit=<n> */
static int __init audit_backlog_limit_set(char *str)
{
u32 audit_backlog_limit_arg;
audit: add kernel set-up parameter to override default backlog limit The default audit_backlog_limit is 64. This was a reasonable limit at one time. systemd causes so much audit queue activity on startup that auditd doesn't start before the backlog queue has already overflowed by more than a factor of 2. On a system with audit= not set on the kernel command line, this isn't an issue since that history isn't kept for auditd when it is available. On a system with audit=1 set on the kernel command line, kaudit tries to keep that history until auditd is able to drain the queue. This default can be changed by the "-b" option in audit.rules once the system has booted, but won't help with lost messages on boot. One way to solve this would be to increase the default backlog queue size to avoid losing any messages before auditd is able to consume them. This would be overkill to the embedded community and insufficient for some servers. Another way to solve it might be to add a kconfig option to set the default based on the system type. An embedded system would get the current (or smaller) default, while Workstations might get more than now and servers might get more. None of these solutions helps if a system's compiled default is too small to see the lost messages without compiling a new kernel. This patch adds a kernel set-up parameter (audit already has one to enable/disable it) "audit_backlog_limit=<n>" that overrides the default to allow the system administrator to set the backlog limit. Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2013-09-17 18:34:52 +02:00
pr_info("audit_backlog_limit: ");
if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
pr_cont("using default of %u, unable to parse %s\n",
audit_backlog_limit, str);
audit: add kernel set-up parameter to override default backlog limit The default audit_backlog_limit is 64. This was a reasonable limit at one time. systemd causes so much audit queue activity on startup that auditd doesn't start before the backlog queue has already overflowed by more than a factor of 2. On a system with audit= not set on the kernel command line, this isn't an issue since that history isn't kept for auditd when it is available. On a system with audit=1 set on the kernel command line, kaudit tries to keep that history until auditd is able to drain the queue. This default can be changed by the "-b" option in audit.rules once the system has booted, but won't help with lost messages on boot. One way to solve this would be to increase the default backlog queue size to avoid losing any messages before auditd is able to consume them. This would be overkill to the embedded community and insufficient for some servers. Another way to solve it might be to add a kconfig option to set the default based on the system type. An embedded system would get the current (or smaller) default, while Workstations might get more than now and servers might get more. None of these solutions helps if a system's compiled default is too small to see the lost messages without compiling a new kernel. This patch adds a kernel set-up parameter (audit already has one to enable/disable it) "audit_backlog_limit=<n>" that overrides the default to allow the system administrator to set the backlog limit. Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2013-09-17 18:34:52 +02:00
return 1;
}
audit_backlog_limit = audit_backlog_limit_arg;
pr_cont("%d\n", audit_backlog_limit);
audit: add kernel set-up parameter to override default backlog limit The default audit_backlog_limit is 64. This was a reasonable limit at one time. systemd causes so much audit queue activity on startup that auditd doesn't start before the backlog queue has already overflowed by more than a factor of 2. On a system with audit= not set on the kernel command line, this isn't an issue since that history isn't kept for auditd when it is available. On a system with audit=1 set on the kernel command line, kaudit tries to keep that history until auditd is able to drain the queue. This default can be changed by the "-b" option in audit.rules once the system has booted, but won't help with lost messages on boot. One way to solve this would be to increase the default backlog queue size to avoid losing any messages before auditd is able to consume them. This would be overkill to the embedded community and insufficient for some servers. Another way to solve it might be to add a kconfig option to set the default based on the system type. An embedded system would get the current (or smaller) default, while Workstations might get more than now and servers might get more. None of these solutions helps if a system's compiled default is too small to see the lost messages without compiling a new kernel. This patch adds a kernel set-up parameter (audit already has one to enable/disable it) "audit_backlog_limit=<n>" that overrides the default to allow the system administrator to set the backlog limit. Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
2013-09-17 18:34:52 +02:00
return 1;
}
__setup("audit_backlog_limit=", audit_backlog_limit_set);
static void audit_buffer_free(struct audit_buffer *ab)
{
unsigned long flags;
if (!ab)
return;
kfree_skb(ab->skb);
spin_lock_irqsave(&audit_freelist_lock, flags);
if (audit_freelist_count > AUDIT_MAXFREE)
kfree(ab);
else {
audit_freelist_count++;
list_add(&ab->list, &audit_freelist);
}
spin_unlock_irqrestore(&audit_freelist_lock, flags);
}
static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
gfp_t gfp_mask, int type)
{
unsigned long flags;
struct audit_buffer *ab = NULL;
struct nlmsghdr *nlh;
spin_lock_irqsave(&audit_freelist_lock, flags);
if (!list_empty(&audit_freelist)) {
ab = list_entry(audit_freelist.next,
struct audit_buffer, list);
list_del(&ab->list);
--audit_freelist_count;
}
spin_unlock_irqrestore(&audit_freelist_lock, flags);
if (!ab) {
ab = kmalloc(sizeof(*ab), gfp_mask);
if (!ab)
goto err;
}
ab->ctx = ctx;
ab->gfp_mask = gfp_mask;
ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
if (!ab->skb)
goto err;
nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
if (!nlh)
goto out_kfree_skb;
return ab;
out_kfree_skb:
kfree_skb(ab->skb);
ab->skb = NULL;
err:
audit_buffer_free(ab);
return NULL;
}
/**
* audit_serial - compute a serial number for the audit record
*
* Compute a serial number for the audit record. Audit records are
* written to user-space as soon as they are generated, so a complete
* audit record may be written in several pieces. The timestamp of the
* record and this serial number are used by the user-space tools to
* determine which pieces belong to the same audit record. The
* (timestamp,serial) tuple is unique for each syscall and is live from
* syscall entry to syscall exit.
*
* NOTE: Another possibility is to store the formatted records off the
* audit context (for those records that have a context), and emit them
* all at syscall exit. However, this could delay the reporting of
* significant errors until syscall exit (or never, if the system
* halts).
*/
unsigned int audit_serial(void)
{
static atomic_t serial = ATOMIC_INIT(0);
return atomic_add_return(1, &serial);
}
static inline void audit_get_stamp(struct audit_context *ctx,
struct timespec *t, unsigned int *serial)
{
if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
*t = CURRENT_TIME;
*serial = audit_serial();
}
}
/**
* audit_log_start - obtain an audit buffer
* @ctx: audit_context (may be NULL)
* @gfp_mask: type of allocation
* @type: audit message type
*
* Returns audit_buffer pointer on success or NULL on error.
*
* Obtain an audit buffer. This routine does locking to obtain the
* audit buffer, but then no locking is required for calls to
* audit_log_*format. If the task (ctx) is a task that is currently in a
* syscall, then the syscall is marked as auditable and an audit record
* will be written at syscall exit. If there is no associated task, then
* task context (ctx) should be NULL.
*/
struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
int type)
{
struct audit_buffer *ab;
struct timespec t;
unsigned int uninitialized_var(serial);
if (audit_initialized != AUDIT_INITIALIZED)
return NULL;
if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE)))
return NULL;
/* don't ever fail/sleep on these two conditions:
* 1. auditd generated record - since we need auditd to drain the
* queue; also, when we are checking for auditd, compare PIDs using
* task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
* using a PID anchored in the caller's namespace
* 2. audit command message - record types 1000 through 1099 inclusive
* are command messages/records used to manage the kernel subsystem
* and the audit userspace, blocking on these messages could cause
* problems under load so don't do it (note: not all of these
* command types are valid as record types, but it is quicker to
* just check two ints than a series of ints in a if/switch stmt) */
if (!((audit_pid && audit_pid == task_tgid_vnr(current)) ||
(type >= 1000 && type <= 1099))) {
long sleep_time = audit_backlog_wait_time;
while (audit_backlog_limit &&
(skb_queue_len(&audit_queue) > audit_backlog_limit)) {
/* wake kauditd to try and flush the queue */
wake_up_interruptible(&kauditd_wait);
/* sleep if we are allowed and we haven't exhausted our
* backlog wait limit */
if ((gfp_mask & __GFP_DIRECT_RECLAIM) &&
(sleep_time > 0)) {
DECLARE_WAITQUEUE(wait, current);
add_wait_queue_exclusive(&audit_backlog_wait,
&wait);
set_current_state(TASK_UNINTERRUPTIBLE);
sleep_time = schedule_timeout(sleep_time);
remove_wait_queue(&audit_backlog_wait, &wait);
} else {
if (audit_rate_check() && printk_ratelimit())
pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
skb_queue_len(&audit_queue),
audit_backlog_limit);
audit_log_lost("backlog limit exceeded");
return NULL;
}
}
}
ab = audit_buffer_alloc(ctx, gfp_mask, type);
if (!ab) {
audit_log_lost("out of memory in audit_log_start");
return NULL;
}
audit_get_stamp(ab->ctx, &t, &serial);
audit_log_format(ab, "audit(%lu.%03lu:%u): ",
t.tv_sec, t.tv_nsec/1000000, serial);
return ab;
}
/**
* audit_expand - expand skb in the audit buffer
* @ab: audit_buffer
* @extra: space to add at tail of the skb
*
* Returns 0 (no space) on failed expansion, or available space if
* successful.
*/
static inline int audit_expand(struct audit_buffer *ab, int extra)
{
struct sk_buff *skb = ab->skb;
int oldtail = skb_tailroom(skb);
int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
int newtail = skb_tailroom(skb);
if (ret < 0) {
audit_log_lost("out of memory in audit_expand");
return 0;
}
skb->truesize += newtail - oldtail;
return newtail;
}
/*
* Format an audit message into the audit buffer. If there isn't enough
* room in the audit buffer, more room will be allocated and vsnprint
* will be called a second time. Currently, we assume that a printk
* can't format message larger than 1024 bytes, so we don't either.
*/
static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
va_list args)
{
int len, avail;
struct sk_buff *skb;
va_list args2;
if (!ab)
return;
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
if (avail == 0) {
avail = audit_expand(ab, AUDIT_BUFSIZ);
if (!avail)
goto out;
}
va_copy(args2, args);
len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
if (len >= avail) {
/* The printk buffer is 1024 bytes long, so if we get
* here and AUDIT_BUFSIZ is at least 1024, then we can
* log everything that printk could have logged. */
avail = audit_expand(ab,
max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
if (!avail)
goto out_va_end;
len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
}
if (len > 0)
skb_put(skb, len);
out_va_end:
va_end(args2);
out:
return;
}
/**
* audit_log_format - format a message into the audit buffer.
* @ab: audit_buffer
* @fmt: format string
* @...: optional parameters matching @fmt string
*
* All the work is done in audit_log_vformat.
*/
void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
{
va_list args;
if (!ab)
return;
va_start(args, fmt);
audit_log_vformat(ab, fmt, args);
va_end(args);
}
/**
* audit_log_hex - convert a buffer to hex and append it to the audit skb
* @ab: the audit_buffer
* @buf: buffer to convert to hex
* @len: length of @buf to be converted
*
* No return value; failure to expand is silently ignored.
*
* This function will take the passed buf and convert it into a string of
* ascii hex digits. The new string is placed onto the skb.
*/
void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
size_t len)
{
int i, avail, new_len;
unsigned char *ptr;
struct sk_buff *skb;
if (!ab)
return;
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
new_len = len<<1;
if (new_len >= avail) {
/* Round the buffer request up to the next multiple */
new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
avail = audit_expand(ab, new_len);
if (!avail)
return;
}
ptr = skb_tail_pointer(skb);
for (i = 0; i < len; i++)
ptr = hex_byte_pack_upper(ptr, buf[i]);
*ptr = 0;
skb_put(skb, len << 1); /* new string is twice the old string */
}
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
/*
* Format a string of no more than slen characters into the audit buffer,
* enclosed in quote marks.
*/
void audit_log_n_string(struct audit_buffer *ab, const char *string,
size_t slen)
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
{
int avail, new_len;
unsigned char *ptr;
struct sk_buff *skb;
if (!ab)
return;
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
BUG_ON(!ab->skb);
skb = ab->skb;
avail = skb_tailroom(skb);
new_len = slen + 3; /* enclosing quotes + null terminator */
if (new_len > avail) {
avail = audit_expand(ab, new_len);
if (!avail)
return;
}
ptr = skb_tail_pointer(skb);
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
*ptr++ = '"';
memcpy(ptr, string, slen);
ptr += slen;
*ptr++ = '"';
*ptr = 0;
skb_put(skb, slen + 2); /* don't include null terminator */
}
/**
* audit_string_contains_control - does a string need to be logged in hex
* @string: string to be checked
* @len: max length of the string to check
*/
bool audit_string_contains_control(const char *string, size_t len)
{
const unsigned char *p;
for (p = string; p < (const unsigned char *)string + len; p++) {
if (*p == '"' || *p < 0x21 || *p > 0x7e)
return true;
}
return false;
}
/**
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
* audit_log_n_untrustedstring - log a string that may contain random characters
* @ab: audit_buffer
* @len: length of string (not including trailing null)
* @string: string to be logged
*
* This code will escape a string that is passed to it if the string
* contains a control character, unprintable character, double quote mark,
* or a space. Unescaped strings will start and end with a double quote mark.
* Strings that are escaped are printed in hex (2 digits per char).
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
*
* The caller specifies the number of characters in the string to log, which may
* or may not be the entire string.
*/
void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
size_t len)
{
if (audit_string_contains_control(string, len))
audit_log_n_hex(ab, string, len);
else
audit_log_n_string(ab, string, len);
}
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
/**
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
* audit_log_untrustedstring - log a string that may contain random characters
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
* @ab: audit_buffer
* @string: string to be logged
*
Audit: add TTY input auditing Add TTY input auditing, used to audit system administrator's actions. This is required by various security standards such as DCID 6/3 and PCI to provide non-repudiation of administrator's actions and to allow a review of past actions if the administrator seems to overstep their duties or if the system becomes misconfigured for unknown reasons. These requirements do not make it necessary to audit TTY output as well. Compared to an user-space keylogger, this approach records TTY input using the audit subsystem, correlated with other audit events, and it is completely transparent to the user-space application (e.g. the console ioctls still work). TTY input auditing works on a higher level than auditing all system calls within the session, which would produce an overwhelming amount of mostly useless audit events. Add an "audit_tty" attribute, inherited across fork (). Data read from TTYs by process with the attribute is sent to the audit subsystem by the kernel. The audit netlink interface is extended to allow modifying the audit_tty attribute, and to allow sending explanatory audit events from user-space (for example, a shell might send an event containing the final command, after the interactive command-line editing and history expansion is performed, which might be difficult to decipher from the TTY input alone). Because the "audit_tty" attribute is inherited across fork (), it would be set e.g. for sshd restarted within an audited session. To prevent this, the audit_tty attribute is cleared when a process with no open TTY file descriptors (e.g. after daemon startup) opens a TTY. See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a more detailed rationale document for an older version of this patch. [akpm@linux-foundation.org: build fix] Signed-off-by: Miloslav Trmac <mitr@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Fulghum <paulkf@microgate.com> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Steve Grubb <sgrubb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 08:40:56 +02:00
* Same as audit_log_n_untrustedstring(), except that strlen is used to
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
* determine string length.
*/
void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
{
audit_log_n_untrustedstring(ab, string, strlen(string));
[PATCH] log more info for directory entry change events When an audit event involves changes to a directory entry, include a PATH record for the directory itself. A few other notable changes: - fixed audit_inode_child() hooks in fsnotify_move() - removed unused flags arg from audit_inode() - added audit log routines for logging a portion of a string Here's some sample output. before patch: type=SYSCALL msg=audit(1149821605.320:26): arch=40000003 syscall=39 success=yes exit=0 a0=bf8d3c7c a1=1ff a2=804e1b8 a3=bf8d3c7c items=1 ppid=739 pid=800 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149821605.320:26): cwd="/root" type=PATH msg=audit(1149821605.320:26): item=0 name="foo" parent=164068 inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 after patch: type=SYSCALL msg=audit(1149822032.332:24): arch=40000003 syscall=39 success=yes exit=0 a0=bfdd9c7c a1=1ff a2=804e1b8 a3=bfdd9c7c items=2 ppid=714 pid=777 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=ttyS0 comm="mkdir" exe="/bin/mkdir" subj=root:system_r:unconfined_t:s0-s0:c0.c255 type=CWD msg=audit(1149822032.332:24): cwd="/root" type=PATH msg=audit(1149822032.332:24): item=0 name="/root" inode=164068 dev=03:00 mode=040750 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_dir_t:s0 type=PATH msg=audit(1149822032.332:24): item=1 name="foo" inode=164010 dev=03:00 mode=040755 ouid=0 ogid=0 rdev=00:00 obj=root:object_r:user_home_t:s0 Signed-off-by: Amy Griffis <amy.griffis@hp.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-06-09 05:19:31 +02:00
}
/* This is a helper-function to print the escaped d_path */
void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
const struct path *path)
{
char *p, *pathname;
if (prefix)
audit_log_format(ab, "%s", prefix);
/* We will allow 11 spaces for ' (deleted)' to be appended */
pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
if (!pathname) {
audit_log_string(ab, "<no_memory>");
return;
}
p = d_path(path, pathname, PATH_MAX+11);
if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
/* FIXME: can we save some information here? */
audit_log_string(ab, "<too_long>");
} else
audit_log_untrustedstring(ab, p);
kfree(pathname);
}
2013-04-30 15:53:34 +02:00
void audit_log_session_info(struct audit_buffer *ab)
{
unsigned int sessionid = audit_get_sessionid(current);
2013-04-30 15:53:34 +02:00
uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
2013-04-30 15:53:34 +02:00
}
void audit_log_key(struct audit_buffer *ab, char *key)
{
audit_log_format(ab, " key=");
if (key)
audit_log_untrustedstring(ab, key);
else
audit_log_format(ab, "(null)");
}
void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
{
int i;
audit_log_format(ab, " %s=", prefix);
CAP_FOR_EACH_U32(i) {
audit_log_format(ab, "%08x",
CAPABILITIES: remove undefined caps from all processes This is effectively a revert of 7b9a7ec565505699f503b4fcf61500dceb36e744 plus fixing it a different way... We found, when trying to run an application from an application which had dropped privs that the kernel does security checks on undefined capability bits. This was ESPECIALLY difficult to debug as those undefined bits are hidden from /proc/$PID/status. Consider a root application which drops all capabilities from ALL 4 capability sets. We assume, since the application is going to set eff/perm/inh from an array that it will clear not only the defined caps less than CAP_LAST_CAP, but also the higher 28ish bits which are undefined future capabilities. The BSET gets cleared differently. Instead it is cleared one bit at a time. The problem here is that in security/commoncap.c::cap_task_prctl() we actually check the validity of a capability being read. So any task which attempts to 'read all things set in bset' followed by 'unset all things set in bset' will not even attempt to unset the undefined bits higher than CAP_LAST_CAP. So the 'parent' will look something like: CapInh: 0000000000000000 CapPrm: 0000000000000000 CapEff: 0000000000000000 CapBnd: ffffffc000000000 All of this 'should' be fine. Given that these are undefined bits that aren't supposed to have anything to do with permissions. But they do... So lets now consider a task which cleared the eff/perm/inh completely and cleared all of the valid caps in the bset (but not the invalid caps it couldn't read out of the kernel). We know that this is exactly what the libcap-ng library does and what the go capabilities library does. They both leave you in that above situation if you try to clear all of you capapabilities from all 4 sets. If that root task calls execve() the child task will pick up all caps not blocked by the bset. The bset however does not block bits higher than CAP_LAST_CAP. So now the child task has bits in eff which are not in the parent. These are 'meaningless' undefined bits, but still bits which the parent doesn't have. The problem is now in cred_cap_issubset() (or any operation which does a subset test) as the child, while a subset for valid cap bits, is not a subset for invalid cap bits! So now we set durring commit creds that the child is not dumpable. Given it is 'more priv' than its parent. It also means the parent cannot ptrace the child and other stupidity. The solution here: 1) stop hiding capability bits in status This makes debugging easier! 2) stop giving any task undefined capability bits. it's simple, it you don't put those invalid bits in CAP_FULL_SET you won't get them in init and you won't get them in any other task either. This fixes the cap_issubset() tests and resulting fallout (which made the init task in a docker container untraceable among other things) 3) mask out undefined bits when sys_capset() is called as it might use ~0, ~0 to denote 'all capabilities' for backward/forward compatibility. This lets 'capsh --caps="all=eip" -- -c /bin/bash' run. 4) mask out undefined bit when we read a file capability off of disk as again likely all bits are set in the xattr for forward/backward compatibility. This lets 'setcap all+pe /bin/bash; /bin/bash' run Signed-off-by: Eric Paris <eparis@redhat.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Andrew Vagin <avagin@openvz.org> Cc: Andrew G. Morgan <morgan@kernel.org> Cc: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: Kees Cook <keescook@chromium.org> Cc: Steve Grubb <sgrubb@redhat.com> Cc: Dan Walsh <dwalsh@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: James Morris <james.l.morris@oracle.com>
2014-07-23 21:36:26 +02:00
cap->cap[CAP_LAST_U32 - i]);
}
}
static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
{
kernel_cap_t *perm = &name->fcap.permitted;
kernel_cap_t *inh = &name->fcap.inheritable;
int log = 0;
if (!cap_isclear(*perm)) {
audit_log_cap(ab, "cap_fp", perm);
log = 1;
}
if (!cap_isclear(*inh)) {
audit_log_cap(ab, "cap_fi", inh);
log = 1;
}
if (log)
audit_log_format(ab, " cap_fe=%d cap_fver=%x",
name->fcap.fE, name->fcap_ver);
}
static inline int audit_copy_fcaps(struct audit_names *name,
const struct dentry *dentry)
{
struct cpu_vfs_cap_data caps;
int rc;
if (!dentry)
return 0;
rc = get_vfs_caps_from_disk(dentry, &caps);
if (rc)
return rc;
name->fcap.permitted = caps.permitted;
name->fcap.inheritable = caps.inheritable;
name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
VFS_CAP_REVISION_SHIFT;
return 0;
}
/* Copy inode data into an audit_names. */
void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
struct inode *inode)
{
name->ino = inode->i_ino;
name->dev = inode->i_sb->s_dev;
name->mode = inode->i_mode;
name->uid = inode->i_uid;
name->gid = inode->i_gid;
name->rdev = inode->i_rdev;
security_inode_getsecid(inode, &name->osid);
audit_copy_fcaps(name, dentry);
}
/**
* audit_log_name - produce AUDIT_PATH record from struct audit_names
* @context: audit_context for the task
* @n: audit_names structure with reportable details
* @path: optional path to report instead of audit_names->name
* @record_num: record number to report when handling a list of names
* @call_panic: optional pointer to int that will be updated if secid fails
*/
void audit_log_name(struct audit_context *context, struct audit_names *n,
const struct path *path, int record_num, int *call_panic)
{
struct audit_buffer *ab;
ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
if (!ab)
return;
audit_log_format(ab, "item=%d", record_num);
if (path)
audit_log_d_path(ab, " name=", path);
else if (n->name) {
switch (n->name_len) {
case AUDIT_NAME_FULL:
/* log the full path */
audit_log_format(ab, " name=");
audit_log_untrustedstring(ab, n->name->name);
break;
case 0:
/* name was specified as a relative path and the
* directory component is the cwd */
audit_log_d_path(ab, " name=", &context->pwd);
break;
default:
/* log the name's directory component */
audit_log_format(ab, " name=");
audit_log_n_untrustedstring(ab, n->name->name,
n->name_len);
}
} else
audit_log_format(ab, " name=(null)");
if (n->ino != AUDIT_INO_UNSET)
audit_log_format(ab, " inode=%lu"
" dev=%02x:%02x mode=%#ho"
" ouid=%u ogid=%u rdev=%02x:%02x",
n->ino,
MAJOR(n->dev),
MINOR(n->dev),
n->mode,
from_kuid(&init_user_ns, n->uid),
from_kgid(&init_user_ns, n->gid),
MAJOR(n->rdev),
MINOR(n->rdev));
if (n->osid != 0) {
char *ctx = NULL;
u32 len;
if (security_secid_to_secctx(
n->osid, &ctx, &len)) {
audit_log_format(ab, " osid=%u", n->osid);
if (call_panic)
*call_panic = 2;
} else {
audit_log_format(ab, " obj=%s", ctx);
security_release_secctx(ctx, len);
}
}
/* log the audit_names record type */
audit_log_format(ab, " nametype=");
switch(n->type) {
case AUDIT_TYPE_NORMAL:
audit_log_format(ab, "NORMAL");
break;
case AUDIT_TYPE_PARENT:
audit_log_format(ab, "PARENT");
break;
case AUDIT_TYPE_CHILD_DELETE:
audit_log_format(ab, "DELETE");
break;
case AUDIT_TYPE_CHILD_CREATE:
audit_log_format(ab, "CREATE");
break;
default:
audit_log_format(ab, "UNKNOWN");
break;
}
audit_log_fcaps(ab, n);
audit_log_end(ab);
}
int audit_log_task_context(struct audit_buffer *ab)
{
char *ctx = NULL;
unsigned len;
int error;
u32 sid;
security_task_getsecid(current, &sid);
if (!sid)
return 0;
error = security_secid_to_secctx(sid, &ctx, &len);
if (error) {
if (error != -EINVAL)
goto error_path;
return 0;
}
audit_log_format(ab, " subj=%s", ctx);
security_release_secctx(ctx, len);
return 0;
error_path:
audit_panic("error in audit_log_task_context");
return error;
}
EXPORT_SYMBOL(audit_log_task_context);
void audit_log_d_path_exe(struct audit_buffer *ab,
struct mm_struct *mm)
{
struct file *exe_file;
if (!mm)
goto out_null;
exe_file = get_mm_exe_file(mm);
if (!exe_file)
goto out_null;
audit_log_d_path(ab, " exe=", &exe_file->f_path);
fput(exe_file);
return;
out_null:
audit_log_format(ab, " exe=(null)");
}
struct tty_struct *audit_get_tty(struct task_struct *tsk)
{
struct tty_struct *tty = NULL;
unsigned long flags;
spin_lock_irqsave(&tsk->sighand->siglock, flags);
if (tsk->signal)
tty = tty_kref_get(tsk->signal->tty);
spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
return tty;
}
void audit_put_tty(struct tty_struct *tty)
{
tty_kref_put(tty);
}
void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
{
const struct cred *cred;
char comm[sizeof(tsk->comm)];
struct tty_struct *tty;
if (!ab)
return;
/* tsk == current */
cred = current_cred();
tty = audit_get_tty(tsk);
audit_log_format(ab,
" ppid=%d pid=%d auid=%u uid=%u gid=%u"
" euid=%u suid=%u fsuid=%u"
" egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
task_ppid_nr(tsk),
task_tgid_nr(tsk),
from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
from_kuid(&init_user_ns, cred->uid),
from_kgid(&init_user_ns, cred->gid),
from_kuid(&init_user_ns, cred->euid),
from_kuid(&init_user_ns, cred->suid),
from_kuid(&init_user_ns, cred->fsuid),
from_kgid(&init_user_ns, cred->egid),
from_kgid(&init_user_ns, cred->sgid),
from_kgid(&init_user_ns, cred->fsgid),
tty ? tty_name(tty) : "(none)",
audit_get_sessionid(tsk));
audit_put_tty(tty);
audit_log_format(ab, " comm=");
audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
audit_log_d_path_exe(ab, tsk->mm);
audit_log_task_context(ab);
}
EXPORT_SYMBOL(audit_log_task_info);
/**
* audit_log_link_denied - report a link restriction denial
* @operation: specific link operation
* @link: the path that triggered the restriction
*/
void audit_log_link_denied(const char *operation, const struct path *link)
{
struct audit_buffer *ab;
struct audit_names *name;
name = kzalloc(sizeof(*name), GFP_NOFS);
if (!name)
return;
/* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
ab = audit_log_start(current->audit_context, GFP_KERNEL,
AUDIT_ANOM_LINK);
if (!ab)
goto out;
audit_log_format(ab, "op=%s", operation);
audit_log_task_info(ab, current);
audit_log_format(ab, " res=0");
audit_log_end(ab);
/* Generate AUDIT_PATH record with object. */
name->type = AUDIT_TYPE_NORMAL;
audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
audit_log_name(current->audit_context, name, link, 0, NULL);
out:
kfree(name);
}
/**
* audit_log_end - end one audit record
* @ab: the audit_buffer
*
* We can not do a netlink send inside an irq context because it blocks (last
* arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
* queue and a tasklet is scheduled to remove them from the queue outside the
* irq context. May be called in any context.
*/
void audit_log_end(struct audit_buffer *ab)
{
if (!ab)
return;
if (!audit_rate_check()) {
audit_log_lost("rate limit exceeded");
} else {
skb_queue_tail(&audit_queue, ab->skb);
wake_up_interruptible(&kauditd_wait);
ab->skb = NULL;
}
audit_buffer_free(ab);
}
/**
* audit_log - Log an audit record
* @ctx: audit context
* @gfp_mask: type of allocation
* @type: audit message type
* @fmt: format string to use
* @...: variable parameters matching the format string
*
* This is a convenience function that calls audit_log_start,
* audit_log_vformat, and audit_log_end. It may be called
* in any context.
*/
void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
const char *fmt, ...)
{
struct audit_buffer *ab;
va_list args;
ab = audit_log_start(ctx, gfp_mask, type);
if (ab) {
va_start(args, fmt);
audit_log_vformat(ab, fmt, args);
va_end(args);
audit_log_end(ab);
}
}
#ifdef CONFIG_SECURITY
/**
* audit_log_secctx - Converts and logs SELinux context
* @ab: audit_buffer
* @secid: security number
*
* This is a helper function that calls security_secid_to_secctx to convert
* secid to secctx and then adds the (converted) SELinux context to the audit
* log by calling audit_log_format, thus also preventing leak of internal secid
* to userspace. If secid cannot be converted audit_panic is called.
*/
void audit_log_secctx(struct audit_buffer *ab, u32 secid)
{
u32 len;
char *secctx;
if (security_secid_to_secctx(secid, &secctx, &len)) {
audit_panic("Cannot convert secid to context");
} else {
audit_log_format(ab, " obj=%s", secctx);
security_release_secctx(secctx, len);
}
}
EXPORT_SYMBOL(audit_log_secctx);
#endif
EXPORT_SYMBOL(audit_log_start);
EXPORT_SYMBOL(audit_log_end);
EXPORT_SYMBOL(audit_log_format);
EXPORT_SYMBOL(audit_log);