diff options
| author | John Johansen <john.johansen@canonical.com> | 2012-02-22 00:32:30 -0800 |
|---|---|---|
| committer | John Johansen <john.johansen@canonical.com> | 2012-02-27 11:38:21 -0800 |
| commit | 8b964eae204d791421677ec56b94a7b18cf8740d (patch) | |
| tree | 7c1a7b5b6be9f2d9b60d8cba1094635d3f74466c /security | |
| parent | ade3ddc01e2e426cc24c744be85dcaad4e8f8aba (diff) | |
| download | lwn-8b964eae204d791421677ec56b94a7b18cf8740d.tar.gz lwn-8b964eae204d791421677ec56b94a7b18cf8740d.zip | |
AppArmor: Fix underflow in xindex calculation
If the xindex value stored in the accept tables is 0, the extraction of
that value will result in an underflow (0 - 4).
In properly compiled policy this should not happen for file rules but
it may be possible for other rule types in the future.
To exploit this underflow a user would have to be able to load a corrupt
policy, which requires CAP_MAC_ADMIN, overwrite system policy in kernel
memory or know of a compiler error resulting in the flaw being present
for loaded policy (no such flaw is known at this time).
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Kees Cook <kees@ubuntu.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/apparmor/include/file.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/security/apparmor/include/file.h b/security/apparmor/include/file.h index ab8c6d87f758..f98fd4701d80 100644 --- a/security/apparmor/include/file.h +++ b/security/apparmor/include/file.h @@ -117,7 +117,7 @@ static inline u16 dfa_map_xindex(u16 mask) index |= AA_X_NAME; } else if (old_index == 3) { index |= AA_X_NAME | AA_X_CHILD; - } else { + } else if (old_index) { index |= AA_X_TABLE; index |= old_index - 4; } |