Commit fb2b2a1d authored Feb 07, 2011 by Tetsuo Handa Committed by Linus Torvalds Feb 07, 2011

CRED: Fix memory and refcount leaks upon security_prepare_creds() failure

In prepare_kernel_cred() since 2.6.29, put_cred(new) is called without
assigning new->usage when security_prepare_creds() returned an error. As a
result, memory for new and refcount for new->{user,group_info,tgcred} are
leaked because put_cred(new) won't call __put_cred() unless old->usage == 1.

Fix these leaks by assigning new->usage (and new->subscribers which was added
in 2.6.32) before calling security_prepare_creds().

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>

parent 2edeaa34

kernel/cred.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -657,6 +657,8 @@ struct cred prepare_kernel_cred(struct task_struct daemon)
		validate_creds(old);

		new = old;
		atomic_set(&new->usage, 1);
		set_cred_subscribers(new, 0);
		get_uid(new->user);
		get_group_info(new->group_info);

		@@ -674,8 +676,6 @@ struct cred prepare_kernel_cred(struct task_struct daemon)
		if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
		goto error;

		atomic_set(&new->usage, 1);
		set_cred_subscribers(new, 0);
		put_cred(old);
		validate_creds(new);
		return new;