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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2011-02-07 14:36:10 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-02-07 23:04:00 +0100 |
| commit | 2edeaa34a6e3f2c43b667f6c4f7b27944b811695 (patch) | |
| tree | 37dd9156645491a86844ba9198fe05e4e6fe44c5 /security/selinux | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6 (diff) | |
| download | linux-2edeaa34a6e3f2c43b667f6c4f7b27944b811695.tar.xz linux-2edeaa34a6e3f2c43b667f6c4f7b27944b811695.zip | |
CRED: Fix BUG() upon security_cred_alloc_blank() failure
In cred_alloc_blank() since 2.6.32, abort_creds(new) is called with
new->security == NULL and new->magic == 0 when security_cred_alloc_blank()
returns an error. As a result, BUG() will be triggered if SELinux is enabled
or CONFIG_DEBUG_CREDENTIALS=y.
If CONFIG_DEBUG_CREDENTIALS=y, BUG() is called from __invalid_creds() because
cred->magic == 0. Failing that, BUG() is called from selinux_cred_free()
because selinux_cred_free() is not expecting cred->security == NULL. This does
not affect smack_cred_free(), tomoyo_cred_free() or apparmor_cred_free().
Fix these bugs by
(1) Set new->magic before calling security_cred_alloc_blank().
(2) Handle null cred->security in creds_are_invalid() and selinux_cred_free().
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security/selinux')
| -rw-r--r-- | security/selinux/hooks.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index e276eb468536..c8d699270687 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3198,7 +3198,11 @@ static void selinux_cred_free(struct cred *cred) { struct task_security_struct *tsec = cred->security; - BUG_ON((unsigned long) cred->security < PAGE_SIZE); + /* + * cred->security == NULL if security_cred_alloc_blank() or + * security_prepare_creds() returned an error. + */ + BUG_ON(cred->security && (unsigned long) cred->security < PAGE_SIZE); cred->security = (void *) 0x7UL; kfree(tsec); } |