Commit 34dc2fd6 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

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: 905ae01c ("Add a reference to ucounts for each cred")
Link: https://lkml.kernel.org/r/87pms2s0v8.fsf_-_@disp2133


Tested-by: default avatarYu Zhao <yuzhao@google.com>
Reviewed-by: default avatarAlexey Gladkov <legion@kernel.org>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 629715ad

kernel/cred.c

+3 −2
Original line number Diff line number Diff line
@@ -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);