# \[PATCH v2 5/5\] ucounts: Handle wrapping in is\_ucounts\_overlimit

- From: Eric W. Biederman \<hidden\>
- Date: 2022-02-16 15:59:31 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2022/02/1673653
- Thread: https://ratatoskr.run/linux-api/2022/02/1673645/t.md

```text
While examining is_ucounts_overlimit and reading the various messages
I realized that is_ucounts_overlimit fails to deal with counts that
may have wrapped.

Being wrapped should be a transitory state for counts and they should
never be wrapped for long, but it can happen so handle it.

Cc: <redacted>
Fixes: 21d1c5e386bc ("Reimplement RLIMIT_NPROC on top of ucounts")
Signed-off-by: "Eric W. Biederman" <redacted>
---
 kernel/ucount.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/ucount.c b/kernel/ucount.c
index 65b597431c86..06ea04d44685 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -350,7 +350,8 @@ bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsign
 	if (rlimit > LONG_MAX)
 		max = LONG_MAX;
 	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-		if (get_ucounts_value(iter, type) > max)
+		long val = get_ucounts_value(iter, type);
+		if (val < 0 || val > max)
 			return true;
 		max = READ_ONCE(iter->ns->ucount_max[type]);
 	}
-- 
2.29.2

```