diff options
| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2011-02-07 13:36:10 +0000 |
|---|---|---|
| committer | AK <andi@firstfloor.org> | 2011-03-31 11:58:05 -0700 |
| commit | 1e1d5bf10f0ee5550bcbfd14dd944a526a68a93e (patch) | |
| tree | 6d1cc0b60d51f97dde419e93192c683dd2886076 /kernel | |
| parent | 693f1255cb838ea0504c0faff7374997cb6c8908 (diff) | |
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>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cred.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/kernel/cred.c b/kernel/cred.c index 60bc8b1e32e6..7d185fe6379f 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -256,13 +256,13 @@ struct cred *cred_alloc_blank(void) #endif atomic_set(&new->usage, 1); +#ifdef CONFIG_DEBUG_CREDENTIALS + new->magic = CRED_MAGIC; +#endif if (security_cred_alloc_blank(new, GFP_KERNEL) < 0) goto error; -#ifdef CONFIG_DEBUG_CREDENTIALS - new->magic = CRED_MAGIC; -#endif return new; error: @@ -754,7 +754,11 @@ bool creds_are_invalid(const struct cred *cred) if (cred->magic != CRED_MAGIC) return true; #ifdef CONFIG_SECURITY_SELINUX - if (selinux_is_enabled()) { + /* + * cred->security == NULL if security_cred_alloc_blank() or + * security_prepare_creds() returned an error. + */ + if (selinux_is_enabled() && cred->security) { if ((unsigned long) cred->security < PAGE_SIZE) return true; if ((*(u32 *)cred->security & 0xffffff00) == |