From: Eric W. Biederman ebiederm@xmission.com
commit 99c31f9feda41d0f10d030dc04ba106c93295aa2 upstream.
Any cred that is destined for use by commit_creds must have a non-NULL cred->ucounts field. Only curing credential construction is a NULL cred->ucounts valid. Only abort_creds, put_cred, and put_cred_rcu needs to deal with a cred with a NULL ucount. As set_cred_ucounts is non of those case don't confuse people by handling something that can not happen.
Link: https://lkml.kernel.org/r/871r4irzds.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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/cred.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)
--- a/kernel/cred.c +++ b/kernel/cred.c @@ -676,15 +676,14 @@ int set_cred_ucounts(struct cred *new) * This optimization is needed because alloc_ucounts() uses locks * for table lookups. */ - if (old_ucounts && old_ucounts->ns == new->user_ns && uid_eq(old_ucounts->uid, new->euid)) + if (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))) return -EAGAIN;
new->ucounts = new_ucounts; - if (old_ucounts) - put_ucounts(old_ucounts); + put_ucounts(old_ucounts);
return 0; }