Commits
Eric Dumazet committed 11c91ef98f3
arp: filter NOARP neighbours for SIOCGARP When arp is off on a device, and ioctl(SIOCGARP) is queried, a buggy answer is given with MAC address of the device, instead of the mac address of the destination/gateway. We filter out NUD_NOARP neighbours for /proc/net/arp, we must do the same for SIOCGARP ioctl. Tested: lpaa23:~# ./arp 10.246.7.190 MAC=00:01:e8:22:cb:1d // correct answer lpaa23:~# ip link set dev eth0 arp off lpaa23:~# cat /proc/net/arp # check arp table is now 'empty' IP address HW type Flags HW address Mask Device lpaa23:~# ./arp 10.246.7.190 MAC=00:1a:11:c3:0d:7f // buggy answer before patch (this is eth0 mac) After patch : lpaa23:~# ip link set dev eth0 arp off lpaa23:~# ./arp 10.246.7.190 ioctl(SIOCGARP) failed: No such device or address Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Vytautas Valancius <valas@google.com> Cc: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>