Commit Graph

18 Commits

Author SHA1 Message Date
John Johansen ed2c7da3a4 apparmor: fix bad lock balance when introspecting policy
BugLink: http://bugs.launchpad.net/bugs/1235977

The profile introspection seq file has a locking bug when policy is viewed
from a virtual root (task in a policy namespace), introspection from the
real root is not affected.

The test for root
    while (parent) {
is correct for the real root, but incorrect for tasks in a policy namespace.
This allows the task to walk backup the policy tree past its virtual root
causing it to be unlocked before the virtual root should be in the p_stop
fn.

This results in the following lockdep back trace:
[   78.479744] [ BUG: bad unlock balance detected! ]
[   78.479792] 3.11.0-11-generic #17 Not tainted
[   78.479838] -------------------------------------
[   78.479885] grep/2223 is trying to release lock (&ns->lock) at:
[   78.479952] [<ffffffff817bf3be>] mutex_unlock+0xe/0x10
[   78.480002] but there are no more locks to release!
[   78.480037]
[   78.480037] other info that might help us debug this:
[   78.480037] 1 lock held by grep/2223:
[   78.480037]  #0:  (&p->lock){+.+.+.}, at: [<ffffffff812111bd>] seq_read+0x3d/0x3d0
[   78.480037]
[   78.480037] stack backtrace:
[   78.480037] CPU: 0 PID: 2223 Comm: grep Not tainted 3.11.0-11-generic #17
[   78.480037] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   78.480037]  ffffffff817bf3be ffff880007763d60 ffffffff817b97ef ffff8800189d2190
[   78.480037]  ffff880007763d88 ffffffff810e1c6e ffff88001f044730 ffff8800189d2190
[   78.480037]  ffffffff817bf3be ffff880007763e00 ffffffff810e5bd6 0000000724fe56b7
[   78.480037] Call Trace:
[   78.480037]  [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[   78.480037]  [<ffffffff817b97ef>] dump_stack+0x54/0x74
[   78.480037]  [<ffffffff810e1c6e>] print_unlock_imbalance_bug+0xee/0x100
[   78.480037]  [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[   78.480037]  [<ffffffff810e5bd6>] lock_release_non_nested+0x226/0x300
[   78.480037]  [<ffffffff817bf2fe>] ? __mutex_unlock_slowpath+0xce/0x180
[   78.480037]  [<ffffffff817bf3be>] ? mutex_unlock+0xe/0x10
[   78.480037]  [<ffffffff810e5d5c>] lock_release+0xac/0x310
[   78.480037]  [<ffffffff817bf2b3>] __mutex_unlock_slowpath+0x83/0x180
[   78.480037]  [<ffffffff817bf3be>] mutex_unlock+0xe/0x10
[   78.480037]  [<ffffffff81376c91>] p_stop+0x51/0x90
[   78.480037]  [<ffffffff81211408>] seq_read+0x288/0x3d0
[   78.480037]  [<ffffffff811e9d9e>] vfs_read+0x9e/0x170
[   78.480037]  [<ffffffff811ea8cc>] SyS_read+0x4c/0xa0
[   78.480037]  [<ffffffff817ccc9d>] system_call_fastpath+0x1a/0x1f

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-10-16 11:54:01 +11:00
John Johansen f8eb8a1324 apparmor: add the ability to report a sha1 hash of loaded policy
Provide userspace the ability to introspect a sha1 hash value for each
profile currently loaded.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
2013-08-14 11:42:08 -07:00
John Johansen 84f1f78742 apparmor: export set of capabilities supported by the apparmor module
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
2013-08-14 11:42:07 -07:00
John Johansen 29b3822f1e apparmor: add the profile introspection file to interface
Add the dynamic namespace relative profiles file to the interace, to allow
introspection of loaded profiles and their modes.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
2013-08-14 11:42:07 -07:00
John Johansen 556d0be74b apparmor: add an optional profile attachment string for profiles
Add the ability to take in and report a human readable profile attachment
string for profiles so that attachment specifications can be easily
inspected.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
2013-08-14 11:42:07 -07:00
John Johansen 0d259f043f apparmor: add interface files for profiles and namespaces
Add basic interface files to access namespace and profile information.
The interface files are created when a profile is loaded and removed
when the profile or namespace is removed.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2013-08-14 11:42:07 -07:00
John Johansen dd51c84857 apparmor: provide base for multiple profiles to be replaced at once
previously profiles had to be loaded one at a time, which could result
in cases where a replacement of a set would partially succeed, and then fail
resulting in inconsistent policy.

Allow multiple profiles to replaced "atomically" so that the replacement
either succeeds or fails for the entire set of profiles.

Signed-off-by: John Johansen <john.johansen@canonical.com>
2013-08-14 11:42:06 -07:00
John Johansen 9d910a3bc0 apparmor: add a features/policy dir to interface
Add a policy directory to features to contain features that can affect
policy compilation but do not affect mediation. Eg of such features would
be types of dfa compression supported, etc.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
2013-08-14 11:42:05 -07:00
Kees Cook d384b0a1a3 AppArmor: export known rlimit names/value mappings in securityfs
Since the parser needs to know which rlimits are known to the kernel,
export the list via a mask file in the "rlimit" subdirectory in the
securityfs "features" directory.

Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2012-02-27 11:38:19 -08:00
Kees Cook a9bf8e9fd5 AppArmor: add "file" details to securityfs
Create the "file" directory in the securityfs for tracking features
related to files.

Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2012-02-27 11:38:18 -08:00
Kees Cook e74abcf335 AppArmor: add initial "features" directory to securityfs
This adds the "features" subdirectory to the AppArmor securityfs
to display boolean features flags and the known capability mask.

Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2012-02-27 11:38:17 -08:00
Kees Cook 9acd494be9 AppArmor: refactor securityfs to use structures
Use a file tree structure to represent the AppArmor securityfs.

Signed-off-by: Kees Cook <kees@ubuntu.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>
2012-02-27 11:38:09 -08:00
Al Viro 52ef0c042b switch securityfs_create_file() to umode_t
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:55:13 -05:00
James Morris 3417d8d5d4 apparmor: sparse fix: make aa_create_aafs static
Sparse fix: make aa_create_aafs static.

Signed-off-by: James Morris <jmorris@namei.org>
Acked-by: John Johansen <john.johansen@canonical.com>
2011-09-09 16:56:25 -07:00
Linus Torvalds 092e0e7e52 Merge branch 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl
* 'llseek' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
  vfs: make no_llseek the default
  vfs: don't use BKL in default_llseek
  llseek: automatically add .llseek fop
  libfs: use generic_file_llseek for simple_attr
  mac80211: disallow seeks in minstrel debug code
  lirc: make chardev nonseekable
  viotape: use noop_llseek
  raw: use explicit llseek file operations
  ibmasmfs: use generic_file_llseek
  spufs: use llseek in all file operations
  arm/omap: use generic_file_llseek in iommu_debug
  lkdtm: use generic_file_llseek in debugfs
  net/wireless: use generic_file_llseek in debugfs
  drm: use noop_llseek
2010-10-22 10:52:56 -07:00
John Johansen 3ed02ada2a AppArmor: Ensure the size of the copy is < the buffer allocated to hold it
Actually I think in this case the appropriate thing to do is to BUG as there
is currently a case (remove) where the alloc_size needs to be larger than
the copy_size, and if copy_size is ever greater than alloc_size there is
a mistake in the caller code.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-10-21 10:12:46 +11:00
Arnd Bergmann 6038f373a3 llseek: automatically add .llseek fop
All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>
2010-10-15 15:53:27 +02:00
John Johansen 63e2b42377 AppArmor: userspace interfaces
The /proc/<pid>/attr/* interface is used for process introspection and
commands.  While the apparmorfs interface is used for global introspection
and loading and removing policy.

The interface currently only contains the files necessary for loading
policy, and will be extended in the future to include sysfs style
single per file introspection inteface.

The old AppArmor 2.4 interface files have been removed into a compatibility
patch, that distros can use to maintain backwards compatibility.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-08-02 15:35:13 +10:00