| From | Andi Kleen <> | Subject | [PATCH] [119/275] CRED: Fix kernel panic upon security_file_alloc() failure. | Date | Wed, 30 Mar 2011 14:05:58 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
commit 78d2978874e4e10e97dfd4fd79db45bdc0748550 upstream.
In get_empty_filp() since 2.6.29, file_free(f) is called with f->f_cred == NULL when security_file_alloc() returned an error. As a result, kernel will panic() due to put_cred(NULL) call within RCU callback.
Fix this bug by assigning f->f_cred before calling security_file_alloc().
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>
--- fs/file_table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.35.y/fs/file_table.c =================================================================== --- linux-2.6.35.y.orig/fs/file_table.c 2011-03-29 22:51:20.759191992 -0700 +++ linux-2.6.35.y/fs/file_table.c 2011-03-29 23:03:00.692282457 -0700 @@ -123,13 +123,13 @@ goto fail; percpu_counter_inc(&nr_files); + f->f_cred = get_cred(cred); if (security_file_alloc(f)) goto fail_sec; INIT_LIST_HEAD(&f->f_u.fu_list); atomic_long_set(&f->f_count, 1); rwlock_init(&f->f_owner.lock); - f->f_cred = get_cred(cred); spin_lock_init(&f->f_lock); eventpoll_init_file(f); /* f->f_version: 0 */
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