From: Andrei Vagin avagin@google.com

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.

v2: changed the goto label name [Roman]

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 --- kernel/ucount.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/ucount.c b/kernel/ucount.c index 8c07714ff27d..9469102c5ac0 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -317,7 +317,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type) for (iter = ucounts; iter; iter = iter->ns->ucounts) { long new = atomic_long_add_return(1, &iter->rlimit[type]); if (new < 0 || new > max) - goto unwind; + goto dec_unwind; if (iter == ucounts) ret = new; max = get_userns_rlimit_max(iter->ns, type); @@ -334,7 +334,6 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type) dec_unwind: dec = atomic_long_sub_return(1, &iter->rlimit[type]); WARN_ON_ONCE(dec < 0); -unwind: do_dec_rlimit_put_ucounts(ucounts, iter, type); return 0; }