ucounts: Proper error handling in set_cred_ucounts

Instead of leaking the ucounts in new if alloc_ucounts fails, store
the result of alloc_ucounts into a temporary variable, which is later
assigned to new->ucounts.

Cc: stable@vger.kernel.org
Fixes: 905ae01c4a ("Add a reference to ucounts for each cred")
Link: https://lkml.kernel.org/r/87pms2s0v8.fsf_-_@disp2133
Tested-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Alexey Gladkov <legion@kernel.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2021-10-16 12:47:51 -05:00
parent 629715adc6
commit 34dc2fd6e6

View File

@ -669,7 +669,7 @@ int set_cred_ucounts(struct cred *new)
{
struct task_struct *task = current;
const struct cred *old = task->real_cred;
struct ucounts *old_ucounts = new->ucounts;
struct ucounts *new_ucounts, *old_ucounts = new->ucounts;
if (new->user == old->user && new->user_ns == old->user_ns)
return 0;
@ -681,9 +681,10 @@ int set_cred_ucounts(struct cred *new)
if (old_ucounts && old_ucounts->ns == new->user_ns && uid_eq(old_ucounts->uid, new->euid))
return 0;
if (!(new->ucounts = alloc_ucounts(new->user_ns, new->euid)))
if (!(new_ucounts = alloc_ucounts(new->user_ns, new->euid)))
return -EAGAIN;
new->ucounts = new_ucounts;
if (old_ucounts)
put_ucounts(old_ucounts);