Commit fd2c83b3 authored by Alexander Potapenko's avatar Alexander Potapenko Committed by David S. Miller

net/packet: check length in getsockopt() called with PACKET_HDRLEN

In the case getsockopt() is called with PACKET_HDRLEN and optlen < 4
|val| remains uninitialized and the syscall may behave differently
depending on its value, and even copy garbage to userspace on certain
architectures. To fix this we now return -EINVAL if optlen is too small.

This bug has been detected with KMSAN.
Signed-off-by: default avatarAlexander Potapenko <glider@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8048ced9
......@@ -3836,6 +3836,8 @@ static int packet_getsockopt(struct socket *sock, int level, int optname,
case PACKET_HDRLEN:
if (len > sizeof(int))
len = sizeof(int);
if (len < sizeof(int))
return -EINVAL;
if (copy_from_user(&val, optval, len))
return -EFAULT;
switch (val) {
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment