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| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2011-02-07 13:36:10 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-02-24 14:54:28 -0800 |
| commit | 4c96bf3813d214d511fc8d14287868ec9f06ab9b (patch) | |
| tree | 770c5fc0998dcae177caf7df16fdb056d0f67d0b /security | |
| parent | 05b3244cf2cfabcb523583cd3c1161d870e70898 (diff) | |
| download | lwn-4c96bf3813d214d511fc8d14287868ec9f06ab9b.tar.gz lwn-4c96bf3813d214d511fc8d14287868ec9f06ab9b.zip | |
CRED: Fix BUG() upon security_cred_alloc_blank() failure
commit 2edeaa34a6e3f2c43b667f6c4f7b27944b811695 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'security')
| -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 11d5c47fefd6..a373ab60dc0b 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); } |