]> git.proxmox.com Git - mirror_ubuntu-hirsute-kernel.git/commitdiff
net/packet: check length in getsockopt() called with PACKET_HDRLEN
authorAlexander Potapenko <glider@google.com>
Tue, 25 Apr 2017 16:51:46 +0000 (18:51 +0200)
committerDavid S. Miller <davem@davemloft.net>
Tue, 25 Apr 2017 18:05:52 +0000 (14:05 -0400)
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: Alexander Potapenko <glider@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/packet/af_packet.c

index 8489beff5c25c971067f38833ed4a790a98dd86e..ea81ccf3c7d6a53095b4922329c25b566d5b5940 100644 (file)
@@ -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) {