[PATCH 1/4] ucounts: In set_cred_ucounts assume new->ucounts is non-NULL

Eric W. Biederman
2021-10-18T17:55:53Z

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.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
kernel/cred.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/kernel/cred.c b/kernel/cred.c
index 1ae0b4948a5a..473d17c431f3 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;
}
--
2.20.1