Commit Graph

311 Commits

Author SHA1 Message Date
Andrey Ulanov 7df9c24625 net: unix: properly re-increment inflight counter of GC discarded candidates
Dmitry has reported that a BUG_ON() condition in unix_notinflight()
may be triggered by a simple code that forwards unix socket in an
SCM_RIGHTS message.
That is caused by incorrect unix socket GC implementation in unix_gc().

The GC first collects list of candidates, then (a) decrements their
"children's" inflight counter, (b) checks which inflight counters are
now 0, and then (c) increments all inflight counters back.
(a) and (c) are done by calling scan_children() with inc_inflight or
dec_inflight as the second argument.

Commit 6209344f5a ("net: unix: fix inflight counting bug in garbage
collector") changed scan_children() such that it no longer considers
sockets that do not have UNIX_GC_CANDIDATE flag. It also added a block
of code that that unsets this flag _before_ invoking
scan_children(, dec_iflight, ). This may lead to incorrect inflight
counters for some sockets.

This change fixes this bug by changing order of operations:
UNIX_GC_CANDIDATE is now unset only after all inflight counters are
restored to the original state.

  kernel BUG at net/unix/garbage.c:149!
  RIP: 0010:[<ffffffff8717ebf4>]  [<ffffffff8717ebf4>]
  unix_notinflight+0x3b4/0x490 net/unix/garbage.c:149
  Call Trace:
   [<ffffffff8716cfbf>] unix_detach_fds.isra.19+0xff/0x170 net/unix/af_unix.c:1487
   [<ffffffff8716f6a9>] unix_destruct_scm+0xf9/0x210 net/unix/af_unix.c:1496
   [<ffffffff86a90a01>] skb_release_head_state+0x101/0x200 net/core/skbuff.c:655
   [<ffffffff86a9808a>] skb_release_all+0x1a/0x60 net/core/skbuff.c:668
   [<ffffffff86a980ea>] __kfree_skb+0x1a/0x30 net/core/skbuff.c:684
   [<ffffffff86a98284>] kfree_skb+0x184/0x570 net/core/skbuff.c:705
   [<ffffffff871789d5>] unix_release_sock+0x5b5/0xbd0 net/unix/af_unix.c:559
   [<ffffffff87179039>] unix_release+0x49/0x90 net/unix/af_unix.c:836
   [<ffffffff86a694b2>] sock_release+0x92/0x1f0 net/socket.c:570
   [<ffffffff86a6962b>] sock_close+0x1b/0x20 net/socket.c:1017
   [<ffffffff81a76b8e>] __fput+0x34e/0x910 fs/file_table.c:208
   [<ffffffff81a771da>] ____fput+0x1a/0x20 fs/file_table.c:244
   [<ffffffff81483ab0>] task_work_run+0x1a0/0x280 kernel/task_work.c:116
   [<     inline     >] exit_task_work include/linux/task_work.h:21
   [<ffffffff8141287a>] do_exit+0x183a/0x2640 kernel/exit.c:828
   [<ffffffff8141383e>] do_group_exit+0x14e/0x420 kernel/exit.c:931
   [<ffffffff814429d3>] get_signal+0x663/0x1880 kernel/signal.c:2307
   [<ffffffff81239b45>] do_signal+0xc5/0x2190 arch/x86/kernel/signal.c:807
   [<ffffffff8100666a>] exit_to_usermode_loop+0x1ea/0x2d0
  arch/x86/entry/common.c:156
   [<     inline     >] prepare_exit_to_usermode arch/x86/entry/common.c:190
   [<ffffffff81009693>] syscall_return_slowpath+0x4d3/0x570
  arch/x86/entry/common.c:259
   [<ffffffff881478e6>] entry_SYSCALL_64_fastpath+0xc4/0xc6

Link: https://lkml.org/lkml/2017/3/6/252
Signed-off-by: Andrey Ulanov <andreyu@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: 6209344 ("net: unix: fix inflight counting bug in garbage collector")
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-21 15:25:10 -07:00
David Howells cdfbabfb2f net: Work around lockdep limitation in sockets that use sockets
Lockdep issues a circular dependency warning when AFS issues an operation
through AF_RXRPC from a context in which the VFS/VM holds the mmap_sem.

The theory lockdep comes up with is as follows:

 (1) If the pagefault handler decides it needs to read pages from AFS, it
     calls AFS with mmap_sem held and AFS begins an AF_RXRPC call, but
     creating a call requires the socket lock:

	mmap_sem must be taken before sk_lock-AF_RXRPC

 (2) afs_open_socket() opens an AF_RXRPC socket and binds it.  rxrpc_bind()
     binds the underlying UDP socket whilst holding its socket lock.
     inet_bind() takes its own socket lock:

	sk_lock-AF_RXRPC must be taken before sk_lock-AF_INET

 (3) Reading from a TCP socket into a userspace buffer might cause a fault
     and thus cause the kernel to take the mmap_sem, but the TCP socket is
     locked whilst doing this:

	sk_lock-AF_INET must be taken before mmap_sem

However, lockdep's theory is wrong in this instance because it deals only
with lock classes and not individual locks.  The AF_INET lock in (2) isn't
really equivalent to the AF_INET lock in (3) as the former deals with a
socket entirely internal to the kernel that never sees userspace.  This is
a limitation in the design of lockdep.

Fix the general case by:

 (1) Double up all the locking keys used in sockets so that one set are
     used if the socket is created by userspace and the other set is used
     if the socket is created by the kernel.

 (2) Store the kern parameter passed to sk_alloc() in a variable in the
     sock struct (sk_kern_sock).  This informs sock_lock_init(),
     sock_init_data() and sk_clone_lock() as to the lock keys to be used.

     Note that the child created by sk_clone_lock() inherits the parent's
     kern setting.

 (3) Add a 'kern' parameter to ->accept() that is analogous to the one
     passed in to ->create() that distinguishes whether kernel_accept() or
     sys_accept4() was the caller and can be passed to sk_alloc().

     Note that a lot of accept functions merely dequeue an already
     allocated socket.  I haven't touched these as the new socket already
     exists before we get the parameter.

     Note also that there are a couple of places where I've made the accepted
     socket unconditionally kernel-based:

	irda_accept()
	rds_rcp_accept_one()
	tcp_accept_from_sock()

     because they follow a sock_create_kern() and accept off of that.

Whilst creating this, I noticed that lustre and ocfs don't create sockets
through sock_create_kern() and thus they aren't marked as for-kernel,
though they appear to be internal.  I wonder if these should do that so
that they use the new set of lock keys.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-09 18:23:27 -08:00
Ingo Molnar 3f07c01441 sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:29 +01:00
Andrey Vagin ba94f3088b unix: add ioctl to open a unix socket file with O_PATH
This ioctl opens a file to which a socket is bound and
returns a file descriptor. The caller has to have CAP_NET_ADMIN
in the socket network namespace.

Currently it is impossible to get a path and a mount point
for a socket file. socket_diag reports address, device ID and inode
number for unix sockets. An address can contain a relative path or
a file may be moved somewhere. And these properties say nothing about
a mount namespace and a mount point of a socket file.

With the introduced ioctl, we can get a path by reading
/proc/self/fd/X and get mnt_id from /proc/self/fdinfo/X.

In CRIU we are going to use this ioctl to dump and restore unix socket.

Here is an example how it can be used:

$ strace -e socket,bind,ioctl ./test /tmp/test_sock
socket(AF_UNIX, SOCK_STREAM, 0)         = 3
bind(3, {sa_family=AF_UNIX, sun_path="test_sock"}, 11) = 0
ioctl(3, SIOCUNIXFILE, 0)           = 4
^Z

$ ss -a | grep test_sock
u_str  LISTEN     0      1      test_sock 17798                 * 0

$ ls -l /proc/760/fd/{3,4}
lrwx------ 1 root root 64 Feb  1 09:41 3 -> 'socket:[17798]'
l--------- 1 root root 64 Feb  1 09:41 4 -> /tmp/test_sock

$ cat /proc/760/fdinfo/4
pos:	0
flags:	012000000
mnt_id:	40

$ cat /proc/self/mountinfo | grep "^40\s"
40 19 0:37 / /tmp rw shared:23 - tmpfs tmpfs rw

Signed-off-by: Andrei Vagin <avagin@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-02-02 21:58:02 -05:00
WANG Cong 0fb44559ff af_unix: move unix_mknod() out of bindlock
Dmitry reported a deadlock scenario:

unix_bind() path:
u->bindlock ==> sb_writer

do_splice() path:
sb_writer ==> pipe->mutex ==> u->bindlock

In the unix_bind() code path, unix_mknod() does not have to
be done with u->bindlock held, since it is a pure fs operation,
so we can just move unix_mknod() out.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-24 14:30:56 -05:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Linus Torvalds ff0f962ca3 Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:
 "This update contains:

   - try to clone on copy-up

   - allow renaming a directory

   - split source into managable chunks

   - misc cleanups and fixes

  It does not contain the read-only fd data inconsistency fix, which Al
  didn't like. I'll leave that to the next year..."

* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (36 commits)
  ovl: fix reStructuredText syntax errors in documentation
  ovl: fix return value of ovl_fill_super
  ovl: clean up kstat usage
  ovl: fold ovl_copy_up_truncate() into ovl_copy_up()
  ovl: create directories inside merged parent opaque
  ovl: opaque cleanup
  ovl: show redirect_dir mount option
  ovl: allow setting max size of redirect
  ovl: allow redirect_dir to default to "on"
  ovl: check for emptiness of redirect dir
  ovl: redirect on rename-dir
  ovl: lookup redirects
  ovl: consolidate lookup for underlying layers
  ovl: fix nested overlayfs mount
  ovl: check namelen
  ovl: split super.c
  ovl: use d_is_dir()
  ovl: simplify lookup
  ovl: check lower existence of rename target
  ovl: rename: simplify handling of lower/merged directory
  ...
2016-12-16 10:58:12 -08:00
Miklos Szeredi beef5121f3 Revert "af_unix: fix hard linked sockets on overlay"
This reverts commit eb0a4a47ae.

Since commit 51f7e52dc9 ("ovl: share inode for hard link") there's no
need to call d_real_inode() to check two overlay inodes for equality.

Side effect of this revert is that it's no longer possible to connect one
socket on overlayfs to one on the underlying layer (something which didn't
make sense anyway).

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16 11:02:53 +01:00
David S. Miller f9aa9dc7d2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
All conflicts were simple overlapping changes except perhaps
for the Thunder driver.

That driver has a change_mtu method explicitly for sending
a message to the hardware.  If that fails it returns an
error.

Normally a driver doesn't need an ndo_change_mtu method becuase those
are usually just range changes, which are now handled generically.
But since this extra operation is needed in the Thunder driver, it has
to stay.

However, if the message send fails we have to restore the original
MTU before the change because the entire call chain expects that if
an error is thrown by ndo_change_mtu then the MTU did not change.
Therefore code is added to nicvf_change_mtu to remember the original
MTU, and to restore it upon nicvf_update_hw_max_frs() failue.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-22 13:27:16 -05:00
WANG Cong 06a77b07e3 af_unix: conditionally use freezable blocking calls in read
Commit 2b15af6f95 ("af_unix: use freezable blocking calls in read")
converts schedule_timeout() to its freezable version, it was probably
correct at that time, but later, commit 2b514574f7
("net: af_unix: implement splice for stream af_unix sockets") breaks
the strong requirement for a freezable sleep, according to
commit 0f9548ca1091:

    We shouldn't try_to_freeze if locks are held.  Holding a lock can cause a
    deadlock if the lock is later acquired in the suspend or hibernate path
    (e.g.  by dpm).  Holding a lock can also cause a deadlock in the case of
    cgroup_freezer if a lock is held inside a frozen cgroup that is later
    acquired by a process outside that group.

The pipe_lock is still held at that point.

So use freezable version only for the recvmsg call path, avoid impact for
Android.

Fixes: 2b514574f7 ("net: af_unix: implement splice for stream af_unix sockets")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Colin Cross <ccross@android.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-18 13:58:39 -05:00
David S. Miller bb598c1b8c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Several cases of bug fixes in 'net' overlapping other changes in
'net-next-.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-15 10:54:36 -05:00
Paolo Abeni 7c13f97ffd udp: do fwd memory scheduling on dequeue
A new argument is added to __skb_recv_datagram to provide
an explicit skb destructor, invoked under the receive queue
lock.
The UDP protocol uses such argument to perform memory
reclaiming on dequeue, so that the UDP protocol does not
set anymore skb->desctructor.
Instead explicit memory reclaiming is performed at close() time and
when skbs are removed from the receive queue.
The in kernel UDP protocol users now need to call a
skb_recv_udp() variant instead of skb_recv_datagram() to
properly perform memory accounting on dequeue.

Overall, this allows acquiring only once the receive queue
lock on dequeue.

Tested using pktgen with random src port, 64 bytes packet,
wire-speed on a 10G link as sender and udp_sink as the receiver,
using an l4 tuple rxhash to stress the contention, and one or more
udp_sink instances with reuseport.

nr sinks	vanilla		patched
1		440		560
3		2150		2300
6		3650		3800
9		4450		4600
12		6250		6450

v1 -> v2:
 - do rmem and allocated memory scheduling under the receive lock
 - do bulk scheduling in first_packet_length() and in udp_destruct_sock()
 - avoid the typdef for the dequeue callback

Suggested-by: Eric Dumazet <edumazet@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-07 13:24:41 -05:00
Isaac Boukris e7947ea770 unix: escape all null bytes in abstract unix domain socket
Abstract unix domain socket may embed null characters,
these should be translated to '@' when printed out to
proc the same way the null prefix is currently being
translated.

This helps for tools such as netstat, lsof and the proc
based implementation in ss to show all the significant
bytes of the name (instead of getting cut at the first
null occurrence).

Signed-off-by: Isaac Boukris <iboukris@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-01 12:15:13 -04:00
Al Viro 25869262ef skb_splice_bits(): get rid of callback
since pipe_lock is the outermost now, we don't need to drop/regain
socket locks around the call of splice_to_pipe() from skb_splice_bits(),
which kills the need to have a socket-specific callback; we can just
call splice_to_pipe() and be done with that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-10-03 20:40:56 -04:00
Linus Torvalds 6e1ce3c345 af_unix: split 'u->readlock' into two: 'iolock' and 'bindlock'
Right now we use the 'readlock' both for protecting some of the af_unix
IO path and for making the bind be single-threaded.

The two are independent, but using the same lock makes for a nasty
deadlock due to ordering with regards to filesystem locking.  The bind
locking would want to nest outside the VSF pathname locking, but the IO
locking wants to nest inside some of those same locks.

We tried to fix this earlier with commit c845acb324 ("af_unix: Fix
splice-bind deadlock") which moved the readlock inside the vfs locks,
but that caused problems with overlayfs that will then call back into
filesystem routines that take the lock in the wrong order anyway.

Splitting the locks means that we can go back to having the bind lock be
the outermost lock, and we don't have any deadlocks with lock ordering.

Acked-by: Rainer Weikusat <rweikusat@cyberadapt.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-04 13:29:29 -07:00
Linus Torvalds 38f7bd94a9 Revert "af_unix: Fix splice-bind deadlock"
This reverts commit c845acb324.

It turns out that it just replaces one deadlock with another one: we can
still get the wrong lock ordering with the readlock due to overlayfs
calling back into the filesystem layer and still taking the vfs locks
after the readlock.

The proper solution ends up being to just split the readlock into two
pieces: the bind lock (taken *outside* the vfs locks) and the IO lock
(taken *inside* the filesystem locks).  The two locks are independent
anyway.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Shmulik Ladkani <shmulik.ladkani@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-04 13:29:29 -07:00
Vladimir Davydov 3aa9799e13 af_unix: charge buffers to kmemcg
Unix sockets can consume a significant amount of system memory, hence
they should be accounted to kmemcg.

Since unix socket buffers are always allocated from process context, all
we need to do to charge them to kmemcg is set __GFP_ACCOUNT in
sock->sk_allocation mask.

Eric asked:

> 1) What happens when a buffer, allocated from socket <A> lands in a
> different socket <B>, maybe owned by another user/process.
>
> Who owns it now, in term of kmemcg accounting ?

We never move memcg charges.  E.g.  if two processes from different
cgroups are sharing a memory region, each page will be charged to the
process which touched it first.  Or if two processes are working with
the same directory tree, inodes and dentries will be charged to the
first user.  The same is fair for unix socket buffers - they will be
charged to the sender.

> 2) Has performance impact been evaluated ?

I ran netperf STREAM_STREAM with default options in a kmemcg on a 4 core
x2 HT box.  The results are below:

 # clients            bandwidth (10^6bits/sec)
                    base              patched
         1      67643 +-  725      64874 +-  353    - 4.0 %
         4     193585 +- 2516     186715 +- 1460    - 3.5 %
         8     194820 +-  377     187443 +- 1229    - 3.7 %

So the accounting doesn't come for free - it takes ~4% of performance.
I believe we could optimize it by using per cpu batching not only on
charge, but also on uncharge in memcg core, but that's beyond the scope
of this patch set - I'll take a look at this later.

Anyway, if performance impact is found to be unacceptable, it is always
possible to disable kmem accounting at boot time (cgroup.memory=nokmem)
or not use memory cgroups at runtime at all (thanks to jump labels
there'll be no overhead even if they are compiled in).

Link: http://lkml.kernel.org/r/fcfe6cae27a59fbc5e40145664b3cf085a560c68.1464079538.git.vdavydov@virtuozzo.com
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26 16:19:19 -07:00
Miklos Szeredi 30402c8949 Merge branch 'overlayfs-af_unix-fix' into overlayfs-linus 2016-06-12 12:05:21 +02:00
Miklos Szeredi eb0a4a47ae af_unix: fix hard linked sockets on overlay
Overlayfs uses separate inodes even in the case of hard links on the
underlying filesystems.  This is a problem for AF_UNIX socket
implementation which indexes sockets based on the inode.  This resulted in
hard linked sockets not working.

The fix is to use the real, underlying inode.

Test case follows:

-- ovl-sock-test.c --
#include <unistd.h>
#include <err.h>
#include <sys/socket.h>
#include <sys/un.h>

#define SOCK "test-sock"
#define SOCK2 "test-sock2"

int main(void)
{
	int fd, fd2;
	struct sockaddr_un addr = {
		.sun_family = AF_UNIX,
		.sun_path = SOCK,
	};
	struct sockaddr_un addr2 = {
		.sun_family = AF_UNIX,
		.sun_path = SOCK2,
	};

	unlink(SOCK);
	unlink(SOCK2);
	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
		err(1, "socket");
	if (bind(fd, (struct sockaddr *) &addr, sizeof(addr)) == -1)
		err(1, "bind");
	if (listen(fd, 0) == -1)
		err(1, "listen");
	if (link(SOCK, SOCK2) == -1)
		err(1, "link");
	if ((fd2 = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
		err(1, "socket");
	if (connect(fd2, (struct sockaddr *) &addr2, sizeof(addr2)) == -1)
		err (1, "connect");
	return 0;
}
----

Reported-by: Alexander Morozov <alexandr.morozov@docker.com> 
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Cc: <stable@vger.kernel.org>
2016-05-20 22:13:45 +02:00
Al Viro d360775217 constify security_path_{mkdir,mknod,symlink}
... as well as unix_mknod() and may_o_create()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-03-28 00:47:27 -04:00
David S. Miller b633353115 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/phy/bcm7xxx.c
	drivers/net/phy/marvell.c
	drivers/net/vxlan.c

All three conflicts were cases of simple overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-23 00:09:14 -05:00
Rainer Weikusat 18eceb818d af_unix: Don't use continue to re-execute unix_stream_read_generic loop
The unix_stream_read_generic function tries to use a continue statement
to restart the receive loop after waiting for a message. This may not
work as intended as the caller might use a recvmsg call to peek at
control messages without specifying a message buffer. If this was the
case, the continue will cause the function to return without an error
and without the credential information if the function had to wait for a
message while it had returned with the credentials otherwise. Change to
using goto to restart the loop without checking the condition first in
this case so that credentials are returned either way.

Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-19 23:50:31 -05:00
Dmitry V. Levin b5f0549231 unix_diag: fix incorrect sign extension in unix_lookup_by_ino
The value passed by unix_diag_get_exact to unix_lookup_by_ino has type
__u32, but unix_lookup_by_ino's argument ino has type int, which is not
a problem yet.
However, when ino is compared with sock_i_ino return value of type
unsigned long, ino is sign extended to signed long, and this results
to incorrect comparison on 64-bit architectures for inode numbers
greater than INT_MAX.

This bug was found by strace test suite.

Fixes: 5d3cae8bc3 ("unix_diag: Dumping exact socket core")
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-19 23:49:23 -05:00
Rainer Weikusat a5527dda34 af_unix: Guard against other == sk in unix_dgram_sendmsg
The unix_dgram_sendmsg routine use the following test

if (unlikely(unix_peer(other) != sk && unix_recvq_full(other))) {

to determine if sk and other are in an n:1 association (either
established via connect or by using sendto to send messages to an
unrelated socket identified by address). This isn't correct as the
specified address could have been bound to the sending socket itself or
because this socket could have been connected to itself by the time of
the unix_peer_get but disconnected before the unix_state_lock(other). In
both cases, the if-block would be entered despite other == sk which
might either block the sender unintentionally or lead to trying to unlock
the same spin lock twice for a non-blocking send. Add a other != sk
check to guard against this.

Fixes: 7d267278a9 ("unix: avoid use-after-free in ep_remove_wait_queue")
Reported-By: Philipp Hahn <pmhahn@pmhahn.de>
Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Tested-by: Philipp Hahn <pmhahn@pmhahn.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-16 12:53:35 -05:00
Rainer Weikusat 1b92ee3d03 af_unix: Don't set err in unix_stream_read_generic unless there was an error
The present unix_stream_read_generic contains various code sequences of
the form

err = -EDISASTER;
if (<test>)
	goto out;

This has the unfortunate side effect of possibly causing the error code
to bleed through to the final

out:
	return copied ? : err;

and then to be wrongly returned if no data was copied because the caller
didn't supply a data buffer, as demonstrated by the program available at

http://pad.lv/1540731

Change it such that err is only set if an error condition was detected.

Fixes: 3822b5c2fc ("af_unix: Revert 'lock_interruptible' in stream receive code")
Reported-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-16 12:48:04 -05:00
Hannes Frederic Sowa 415e3d3e90 unix: correctly track in-flight fds in sending process user_struct
The commit referenced in the Fixes tag incorrectly accounted the number
of in-flight fds over a unix domain socket to the original opener
of the file-descriptor. This allows another process to arbitrary
deplete the original file-openers resource limit for the maximum of
open files. Instead the sending processes and its struct cred should
be credited.

To do so, we add a reference counted struct user_struct pointer to the
scm_fp_list and use it to account for the number of inflight unix fds.

Fixes: 712f4aad40 ("unix: properly account for FDs passed over unix sockets")
Reported-by: David Herrmann <dh.herrmann@gmail.com>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-08 10:30:42 -05:00
David Herrmann 3575dbf2cb net: drop write-only stack variable
Remove a write-only stack variable from unix_attach_fds(). This is a
left-over from the security fix in:

    commit 712f4aad40
    Author: willy tarreau <w@1wt.eu>
    Date:   Sun Jan 10 07:54:56 2016 +0100

        unix: properly account for FDs passed over unix sockets

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-07 14:06:26 -05:00
Eric Dumazet fa0dc04df2 af_unix: fix struct pid memory leak
Dmitry reported a struct pid leak detected by a syzkaller program.

Bug happens in unix_stream_recvmsg() when we break the loop when a
signal is pending, without properly releasing scm.

Fixes: b3ca9b02b0 ("net: fix multithreaded signal handling in unix recv routines")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-01-24 22:04:49 -08:00
David S. Miller 9d367eddf3 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/bonding/bond_main.c
	drivers/net/ethernet/mellanox/mlxsw/spectrum.h
	drivers/net/ethernet/mellanox/mlxsw/spectrum_switchdev.c

The bond_main.c and mellanox switch conflicts were cases of
overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2016-01-11 23:55:43 -05:00
willy tarreau 712f4aad40 unix: properly account for FDs passed over unix sockets
It is possible for a process to allocate and accumulate far more FDs than
the process' limit by sending them over a unix socket then closing them
to keep the process' fd count low.

This change addresses this problem by keeping track of the number of FDs
in flight per user and preventing non-privileged processes from having
more FDs in flight than their configured FD limit.

Reported-by: socketpair@gmail.com
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Mitigates: CVE-2013-4312 (Linux 2.0+)
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-01-11 00:05:30 -05:00
David S. Miller 9e0efaf6b4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2016-01-06 22:54:18 -05:00
Rainer Weikusat c845acb324 af_unix: Fix splice-bind deadlock
On 2015/11/06, Dmitry Vyukov reported a deadlock involving the splice
system call and AF_UNIX sockets,

http://lists.openwall.net/netdev/2015/11/06/24

The situation was analyzed as

(a while ago) A: socketpair()
B: splice() from a pipe to /mnt/regular_file
	does sb_start_write() on /mnt
C: try to freeze /mnt
	wait for B to finish with /mnt
A: bind() try to bind our socket to /mnt/new_socket_name
	lock our socket, see it not bound yet
	decide that it needs to create something in /mnt
	try to do sb_start_write() on /mnt, block (it's
	waiting for C).
D: splice() from the same pipe to our socket
	lock the pipe, see that socket is connected
	try to lock the socket, block waiting for A
B:	get around to actually feeding a chunk from
	pipe to file, try to lock the pipe.  Deadlock.

on 2015/11/10 by Al Viro,

http://lists.openwall.net/netdev/2015/11/10/4

The patch fixes this by removing the kern_path_create related code from
unix_mknod and executing it as part of unix_bind prior acquiring the
readlock of the socket in question. This means that A (as used above)
will sb_start_write on /mnt before it acquires the readlock, hence, it
won't indirectly block B which first did a sb_start_write and then
waited for a thread trying to acquire the readlock. Consequently, A
being blocked by C waiting for B won't cause a deadlock anymore
(effectively, both A and B acquire two locks in opposite order in the
situation described above).

Dmitry Vyukov(<dvyukov@google.com>) tested the original patch.

Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-01-04 23:22:49 -05:00
David S. Miller b3e0d3d7ba Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/geneve.c

Here we had an overlapping change, where in 'net' the extraneous stats
bump was being removed whilst in 'net-next' the final argument to
udp_tunnel6_xmit_skb() was being changed.

Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-17 22:08:28 -05:00
Rainer Weikusat 3822b5c2fc af_unix: Revert 'lock_interruptible' in stream receive code
With b3ca9b02b0, the AF_UNIX SOCK_STREAM
receive code was changed from using mutex_lock(&u->readlock) to
mutex_lock_interruptible(&u->readlock) to prevent signals from being
delayed for an indefinite time if a thread sleeping on the mutex
happened to be selected for handling the signal. But this was never a
problem with the stream receive code (as opposed to its datagram
counterpart) as that never went to sleep waiting for new messages with the
mutex held and thus, wouldn't cause secondary readers to block on the
mutex waiting for the sleeping primary reader. As the interruptible
locking makes the code more complicated in exchange for no benefit,
change it back to using mutex_lock.

Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-17 15:33:47 -05:00
Rainer Weikusat 6487428088 af_unix: fix unix_dgram_recvmsg entry locking
The current unix_dgram_recvsmg code acquires the u->readlock mutex in
order to protect access to the peek offset prior to calling
__skb_recv_datagram for actually receiving data. This implies that a
blocking reader will go to sleep with this mutex held if there's
presently no data to return to userspace. Two non-desirable side effects
of this are that a later non-blocking read call on the same socket will
block on the ->readlock mutex until the earlier blocking call releases it
(or the readers is interrupted) and that later blocking read calls
will wait longer than the effective socket read timeout says they
should: The timeout will only start 'ticking' once such a reader hits
the schedule_timeout in wait_for_more_packets (core.c) while the time it
already had to wait until it could acquire the mutex is unaccounted for.

The patch avoids both by using the __skb_try_recv_datagram and
__skb_wait_for_more packets functions created by the first patch to
implement a unix_dgram_recvmsg read loop which releases the readlock
mutex prior to going to sleep and reacquires it as needed
afterwards. Non-blocking readers will thus immediately return with
-EAGAIN if there's no data available regardless of any concurrent
blocking readers and all blocking readers will end up sleeping via
schedule_timeout, thus honouring the configured socket receive timeout.

Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-06 23:31:54 -05:00
David S. Miller f188b951f3 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/ethernet/renesas/ravb_main.c
	kernel/bpf/syscall.c
	net/ipv4/ipmr.c

All three conflicts were cases of overlapping changes.

Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-03 21:09:12 -05:00
Eric Dumazet 9cd3e072b0 net: rename SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA
This patch is a cleanup to make following patch easier to
review.

Goal is to move SOCK_ASYNC_NOSPACE and SOCK_ASYNC_WAITDATA
from (struct socket)->flags to a (struct socket_wq)->flags
to benefit from RCU protection in sock_wake_async()

To ease backports, we rename both constants.

Two new helpers, sk_set_bit(int nr, struct sock *sk)
and sk_clear_bit(int net, struct sock *sk) are added so that
following patch can change their implementation.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-01 15:45:05 -05:00
Rainer Weikusat 77b75f4d8c unix: use wq_has_sleeper in unix_dgram_recvmsg
The current unix_dgram_recvmsg does a wake up for every received
datagram. This seems wasteful as only SOCK_DGRAM client sockets in an
n:1 association with a server socket will ever wait because of the
associated condition. The patch below changes the function such that the
wake up only happens if wq_has_sleeper indicates that someone actually
wants to be notified. Testing with SOCK_SEQPACKET and SOCK_DGRAM socket
seems to confirm that this is an improvment.

Signed-Off-By: Rainer Weikusat <rweikusat@mobileactivedefense.com>

Signed-off-by: David S. Miller <davem@davemloft.net>
2015-12-01 14:57:43 -05:00
Hannes Frederic Sowa 9490f886b1 af-unix: passcred support for sendpage
sendpage did not care about credentials at all. This could lead to
situations in which because of fd passing between processes we could
append data to skbs with different scm data. It is illegal to splice those
skbs together. Instead we have to allocate a new skb and if requested
fill out the scm details.

Fixes: 869e7c6248 ("net: af_unix: implement stream sendpage support")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-30 15:16:06 -05:00
Herbert Xu 1ce0bf50ae net: Generalise wq_has_sleeper helper
The memory barrier in the helper wq_has_sleeper is needed by just
about every user of waitqueue_active.  This patch generalises it
by making it take a wait_queue_head_t directly.  The existing
helper is renamed to skwq_has_sleeper.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-30 14:47:33 -05:00
Rainer Weikusat 7d267278a9 unix: avoid use-after-free in ep_remove_wait_queue
Rainer Weikusat <rweikusat@mobileactivedefense.com> writes:
An AF_UNIX datagram socket being the client in an n:1 association with
some server socket is only allowed to send messages to the server if the
receive queue of this socket contains at most sk_max_ack_backlog
datagrams. This implies that prospective writers might be forced to go
to sleep despite none of the message presently enqueued on the server
receive queue were sent by them. In order to ensure that these will be
woken up once space becomes again available, the present unix_dgram_poll
routine does a second sock_poll_wait call with the peer_wait wait queue
of the server socket as queue argument (unix_dgram_recvmsg does a wake
up on this queue after a datagram was received). This is inherently
problematic because the server socket is only guaranteed to remain alive
for as long as the client still holds a reference to it. In case the
connection is dissolved via connect or by the dead peer detection logic
in unix_dgram_sendmsg, the server socket may be freed despite "the
polling mechanism" (in particular, epoll) still has a pointer to the
corresponding peer_wait queue. There's no way to forcibly deregister a
wait queue with epoll.

Based on an idea by Jason Baron, the patch below changes the code such
that a wait_queue_t belonging to the client socket is enqueued on the
peer_wait queue of the server whenever the peer receive queue full
condition is detected by either a sendmsg or a poll. A wake up on the
peer queue is then relayed to the ordinary wait queue of the client
socket via wake function. The connection to the peer wait queue is again
dissolved if either a wake up is about to be relayed or the client
socket reconnects or a dead peer is detected or the client socket is
itself closed. This enables removing the second sock_poll_wait from
unix_dgram_poll, thus avoiding the use-after-free, while still ensuring
that no blocked writer sleeps forever.

Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Fixes: ec0d215f94 ("af_unix: fix 'poll for write'/connected DGRAM sockets")
Reviewed-by: Jason Baron <jbaron@akamai.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-23 12:29:58 -05:00
Hannes Frederic Sowa a3a116e04c af_unix: take receive queue lock while appending new skb
While possibly in future we don't necessarily need to use
sk_buff_head.lock this is a rather larger change, as it affects the
af_unix fd garbage collector, diag and socket cleanups. This is too much
for a stable patch.

For the time being grab sk_buff_head.lock without disabling bh and irqs,
so don't use locked skb_queue_tail.

Fixes: 869e7c6248 ("net: af_unix: implement stream sendpage support")
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Reported-by: Eric Dumazet <edumazet@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-17 15:25:45 -05:00
Hannes Frederic Sowa 8844f97238 af_unix: don't append consumed skbs to sk_receive_queue
In case multiple writes to a unix stream socket race we could end up in a
situation where we pre-allocate a new skb for use in unix_stream_sendpage
but have to free it again in the locked section because another skb
has been appended meanwhile, which we must use. Accidentally we didn't
clear the pointer after consuming it and so we touched freed memory
while appending it to the sk_receive_queue. So, clear the pointer after
consuming the skb.

This bug has been found with syzkaller
(http://github.com/google/syzkaller) by Dmitry Vyukov.

Fixes: 869e7c6248 ("net: af_unix: implement stream sendpage support")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-16 15:39:35 -05:00
Hannes Frederic Sowa 73ed5d25dc af-unix: fix use-after-free with concurrent readers while splicing
During splicing an af-unix socket to a pipe we have to drop all
af-unix socket locks. While doing so we allow another reader to enter
unix_stream_read_generic which can read, copy and finally free another
skb. If exactly this skb is just in process of being spliced we get a
use-after-free report by kasan.

First, we must make sure to not have a free while the skb is used during
the splice operation. We simply increment its use counter before unlocking
the reader lock.

Stream sockets have the nice characteristic that we don't care about
zero length writes and they never reach the peer socket's queue. That
said, we can take the UNIXCB.consumed field as the indicator if the
skb was already freed from the socket's receive queue. If the skb was
fully consumed after we locked the reader side again we know it has been
dropped by a second reader. We indicate a short read to user space and
abort the current splice operation.

This bug has been found with syzkaller
(http://github.com/google/syzkaller) by Dmitry Vyukov.

Fixes: 2b514574f7 ("net: af_unix: implement splice for stream af_unix sockets")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-11-15 13:16:34 -05:00
Eric Dumazet 1586a5877d af_unix: do not report POLLOUT on listeners
poll(POLLOUT) on a listener should not report fd is ready for
a write().

This would break some applications using poll() and pfd.events = -1,
as they would not block in poll()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Alan Burlison <Alan.Burlison@oracle.com>
Tested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-25 06:37:45 -07:00
Andrey Vagin e9193d60d3 net/unix: fix logic about sk_peek_offset
Now send with MSG_PEEK can return data from multiple SKBs.

Unfortunately we take into account the peek offset for each skb,
that is wrong. We need to apply the peek offset only once.

In addition, the peek offset should be used only if MSG_PEEK is set.

Cc: "David S. Miller" <davem@davemloft.net> (maintainer:NETWORKING
Cc: Eric Dumazet <edumazet@google.com> (commit_signer:1/14=7%)
Cc: Aaron Conole <aconole@bytheb.org>
Fixes: 9f389e3567 ("af_unix: return data from multiple SKBs on recv() with MSG_PEEK flag")
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Tested-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-10-05 06:33:09 -07:00
Aaron Conole 9f389e3567 af_unix: return data from multiple SKBs on recv() with MSG_PEEK flag
AF_UNIX sockets now return multiple skbs from recv() when MSG_PEEK flag
is set.

This is referenced in kernel bugzilla #12323 @
https://bugzilla.kernel.org/show_bug.cgi?id=12323

As described both in the BZ and lkml thread @
http://lkml.org/lkml/2008/1/8/444 calling recv() with MSG_PEEK on an
AF_UNIX socket only reads a single skb, where the desired effect is
to return as much skb data has been queued, until hitting the recv
buffer size (whichever comes first).

The modified MSG_PEEK path will now move to the next skb in the tree
and jump to the again: label, rather than following the natural loop
structure. This requires duplicating some of the loop head actions.

This was tested using the python socketpair python code attached to
the bugzilla issue.

Signed-off-by: Aaron Conole <aconole@bytheb.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-09-29 13:47:08 -07:00
Stephen Smalley 37a9a8df8c net/unix: support SCM_SECURITY for stream sockets
SCM_SECURITY was originally only implemented for datagram sockets,
not for stream sockets.  However, SCM_CREDENTIALS is supported on
Unix stream sockets.  For consistency, implement Unix stream support
for SCM_SECURITY as well.  Also clean up the existing code and get
rid of the superfluous UNIXSID macro.

Motivated by https://bugzilla.redhat.com/show_bug.cgi?id=1224211,
where systemd was using SCM_CREDENTIALS and assumed wrongly that
SCM_SECURITY was also supported on Unix stream sockets.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-10 22:49:20 -07:00
David S. Miller dda922c831 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/phy/amd-xgbe-phy.c
	drivers/net/wireless/iwlwifi/Kconfig
	include/net/mac80211.h

iwlwifi/Kconfig and mac80211.h were both trivial overlapping
changes.

The drivers/net/phy/amd-xgbe-phy.c file got removed in 'net-next' and
the bug fix that happened on the 'net' side is already integrated
into the rest of the amd-xgbe driver.

Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-01 22:51:30 -07:00
Mark Salyzyn b48732e4a4 unix/caif: sk_socket can disappear when state is unlocked
got a rare NULL pointer dereference in clear_bit

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
----
v2: switch to sock_flag(sk, SOCK_DEAD) and added net/caif/caif_socket.c
v3: return -ECONNRESET in upstream caller of wait function for SOCK_DEAD
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-26 23:19:29 -04:00