5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andrei Vagin avagin@google.com
commit 432dc0654c612457285a5dcf9bb13968ac6f0804 upstream.
The inc_rlimit_get_ucounts() increments the specified rlimit counter and then checks its limit. If the value exceeds the limit, the function returns an error without decrementing the counter.
Link: https://lkml.kernel.org/r/20241101191940.3211128-1-roman.gushchin@linux.dev Fixes: 15bc01effefe ("ucounts: Fix signal ucount refcounting") Signed-off-by: Andrei Vagin avagin@google.com Co-developed-by: Roman Gushchin roman.gushchin@linux.dev Signed-off-by: Roman Gushchin roman.gushchin@linux.dev Tested-by: Roman Gushchin roman.gushchin@linux.dev Acked-by: Alexey Gladkov legion@kernel.org Cc: Kees Cook kees@kernel.org Cc: Andrei Vagin avagin@google.com Cc: "Eric W. Biederman" ebiederm@xmission.com Cc: Alexey Gladkov legion@kernel.org Cc: Oleg Nesterov oleg@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/ucount.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -315,7 +315,7 @@ long inc_rlimit_get_ucounts(struct ucoun for (iter = ucounts; iter; iter = iter->ns->ucounts) { long new = atomic_long_add_return(1, &iter->ucount[type]); if (new < 0 || new > max) - goto unwind; + goto dec_unwind; if (iter == ucounts) ret = new; max = READ_ONCE(iter->ns->ucount_max[type]); @@ -332,7 +332,6 @@ long inc_rlimit_get_ucounts(struct ucoun dec_unwind: dec = atomic_long_add_return(-1, &iter->ucount[type]); WARN_ON_ONCE(dec < 0); -unwind: do_dec_rlimit_put_ucounts(ucounts, iter, type); return 0; }