From e260ad01f0aa9e96b5386d5cd7184afd949dc457 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Tue, 14 May 2019 15:44:55 -0700 Subject: sysctl: return -EINVAL if val violates minmax Currently when userspace gives us a values that overflow e.g. file-max and other callers of __do_proc_doulongvec_minmax() we simply ignore the new value and leave the current value untouched. This can be problematic as it gives the illusion that the limit has indeed be bumped when in fact it failed. This commit makes sure to return EINVAL when an overflow is detected. Please note that this is a userspace facing change. Link: http://lkml.kernel.org/r/20190210203943.8227-4-christian@brauner.io Signed-off-by: Christian Brauner Acked-by: Luis Chamberlain Cc: Kees Cook Cc: Alexey Dobriyan Cc: Al Viro Cc: Dominik Brodowski Cc: "Eric W. Biederman" Cc: Joe Lawrence Cc: Waiman Long Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sysctl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index d82f9161adb8..f7bd1aead3bf 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2886,8 +2886,10 @@ static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int if (neg) continue; val = convmul * val / convdiv; - if ((min && val < *min) || (max && val > *max)) - continue; + if ((min && val < *min) || (max && val > *max)) { + err = -EINVAL; + break; + } *i = val; } else { val = convdiv * (*i) / convmul; -- cgit v1.2.3-59-g8ed1b