On 9.03.23 г. 12:37 ч., Nikolay Borisov wrote:
When preforming setuid the general expectation is that the underlying
user_struct will also be changed. However, in our kernels this doesn't
hold true to the presence of ff716deacf0c ("userns: associate user_struct
with the user_namespace").
Running userns08 testcase from ltp causes a warning to be triggered
when decrementing NPROC count on process reap. The reason for the
warning is when the uid is changed the relevant code in commit_cred()
is supposed to adjust the ucounts for the old (pre-setuid) and new
(after setuid) state. However, the ceck in the upstream kernel only
triggers if userns or user_struct have changed. Fix the issue by
augmenting the check to ensure NPROC is adjusted when just the uid is
changed.
https://jira.sw.ru/browse/PSBM-145641
Signed-off-by: Nikolay Borisov <[email protected]>
---
kernel/cred.c | 16 ++++++++++++++--
1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/kernel/cred.c b/kernel/cred.c
index 96466cc1c527..7dedd97a27c2 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -395,6 +395,9 @@ int copy_creds(struct task_struct *p, unsigned long
clone_flags)
#endif
p->cred = p->real_cred = get_cred(new);
+ trace_printk("incr rlim for ns: %u val: %ld uid: %u euid: %u ucounts: %p\n",
task_ucounts(p)->ns->ns.inum,
+
atomic_long_read(&task_ucounts(p)->ucount[UCOUNT_RLIMIT_NPROC]),
+ task_uid(p).val, task_euid(p).val, task_ucounts(p));
inc_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
alter_cred_subscribers(new, 2);
validate_creds(new);
@@ -495,12 +498,21 @@ int commit_creds(struct cred *new)
* in set_user().
*/
alter_cred_subscribers(new, 2);
- if (new->user != old->user || new->user_ns != old->user_ns)
+ trace_printk("User adjustment\n");
+ if (new->user != old->user || new->user_ns != old->user_ns ||
!uid_eq(new->uid, old->uid)) {
+ trace_printk("incr rlim for ns: %u val: %ld nuid: %u ouid: %u new ucount: %p
old ucount: %p\n", new->ucounts->ns->ns.inum,
+
atomic_long_read(&new->ucounts->ucount[UCOUNT_RLIMIT_NPROC]),
__kuid_val(new->uid), __kuid_val(old->uid),
+ new->ucounts, old->ucounts);
Grrr, those trace_printk's calls were used during debugging and weren't
supposed to be included in the patch. Konstantin when applying would you
please drop me or shall I resend without them?
+
inc_rlimit_ucounts(new->ucounts, UCOUNT_RLIMIT_NPROC, 1);
+ }
rcu_assign_pointer(task->real_cred, new);
rcu_assign_pointer(task->cred, new);
- if (new->user != old->user || new->user_ns != old->user_ns)
+ if (new->user != old->user || new->user_ns != old->user_ns ||
!uid_eq(new->uid, old->uid) ) {
+ trace_printk("decr rlim for ns: %u val: %ld\n",
old->ucounts->ns->ns.inum,
+
atomic_long_read(&old->ucounts->ucount[UCOUNT_RLIMIT_NPROC]));
dec_rlimit_ucounts(old->ucounts, UCOUNT_RLIMIT_NPROC, 1);
+ }
alter_cred_subscribers(old, -2);
/* send notifications */
--
2.34.1
_______________________________________________
Devel mailing list
[email protected]
https://lists.openvz.org/mailman/listinfo/devel
