4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Willem de Bruijn <willemb@xxxxxxxxxx> [ Upstream commit 99137b7888f4058087895d035d81c6b2d31015c5 ] Packet sockets with SOCK_DGRAM may pass an address for use in dev_hard_header. Ensure that it is of sufficient length. Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx> Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/packet/af_packet.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2662,6 +2662,8 @@ static int tpacket_snd(struct packet_soc proto = saddr->sll_protocol; addr = saddr->sll_addr; dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex); + if (addr && dev && saddr->sll_halen < dev->addr_len) + goto out; } err = -ENXIO; @@ -2859,6 +2861,8 @@ static int packet_snd(struct socket *soc proto = saddr->sll_protocol; addr = saddr->sll_addr; dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex); + if (addr && dev && saddr->sll_halen < dev->addr_len) + goto out; } err = -ENXIO;
