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Subject[PATCH 2/2] CRED: Fix memory and refcount leaks upon security_prepare_creds() failure
Date
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

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>
---

kernel/cred.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cred.c b/kernel/cred.c
index fcf104b..3a9d6dd 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -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;


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