From f418bfabea43325f306276226f64ebc7de1b7d56 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 16 Oct 2021 12:51:58 -0500 Subject: [PATCH] ucounts: In set_cred_ucounts assume new->ucounts is non-NULL 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 Reviewed-by: Alexey Gladkov Signed-off-by: "Eric W. Biederman" Signed-off-by: Greg Kroah-Hartman --- kernel/cred.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/cred.c b/kernel/cred.c index 1ae0b49..473d17c 100644 --- 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; } -- 2.7.4