From 9eee85ed843fbec123e39a330495cfc4ca2b871f Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Fri, 21 Dec 2018 12:06:59 -0500 Subject: [PATCH] packet: validate address length [ 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 Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 88d5b2645bb0..e63d207047ce 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2665,6 +2665,8 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) 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; @@ -2863,6 +2865,8 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) 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; -- 2.20.1