From: Willem de Bruijn <willemb@google.com>
Date: Fri, 21 Dec 2018 17:06:59 +0000 (-0500)
Subject: packet: validate address length
X-Git-Tag: v3.18.132~35
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6a40c2da9c01785f089ca502edaf99a8e8eef4bc;p=thirdparty%2Fkernel%2Fstable.git

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 <syzkaller@googlegroups.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 473858cb4c5d1..bd174f9f62f1c 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2275,6 +2275,8 @@ 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;
@@ -2436,6 +2438,8 @@ 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;