[ Upstream commit e260ad01f0aa9e96b5386d5cd7184afd949dc457 ]
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 christian@brauner.io Acked-by: Luis Chamberlain mcgrof@kernel.org Cc: Kees Cook keescook@chromium.org Cc: Alexey Dobriyan adobriyan@gmail.com Cc: Al Viro viro@zeniv.linux.org.uk Cc: Dominik Brodowski linux@dominikbrodowski.net Cc: "Eric W. Biederman" ebiederm@xmission.com Cc: Joe Lawrence joe.lawrence@redhat.com Cc: Waiman Long longman@redhat.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/sysctl.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c9ec050bcf46..387efbaf464a 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -2874,8 +2874,10 @@ 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;