On 2/16/22 8:58 AM, Eric W. Biederman wrote:
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: stable@xxxxxxxxxxxxxxx
Fixes: 21d1c5e386bc ("Reimplement RLIMIT_NPROC on top of ucounts")
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
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]);
}
This addresses the concerns about overflow.
Reviewed-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
thanks,
-- Shuah
