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

commit fb2b2a1d37f80cc818fd4487b510f4e11816e5e1 upstream.

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>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/kernel/cred.c b/kernel/cred.c
index 9a85aeec49335cfa009b0de6fa997e7cb5b5c98c..aa66d6f69f21db44a73076fa75f5ee44c6642d74 100644 (file)
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -725,6 +725,8 @@ 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);
 
@@ -742,8 +744,6 @@ 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;