[PATCH 3.18 14/47] packet: validate address length if non-zero

[Greg Kroah-Hartman]

3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Willem de Bruijn <will...@google.com>

[ Upstream commit 6b8d95f1795c42161dc0984b6863e95d6acf24ed ]

Validate packet socket address length if a length is given. Zero
length is equivalent to not setting an address.

Fixes: 99137b7888f4 ("packet: validate address length")
Reported-by: Ido Schimmel <ido...@idosch.org>
Signed-off-by: Willem de Bruijn <will...@google.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/packet/af_packet.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2273,7 +2273,7 @@ static int tpacket_snd(struct packet_soc
                                                sll_addr)))
                        goto out;
                proto   = saddr->sll_protocol;
-               addr    = saddr->sll_addr;
+               addr    = saddr->sll_halen ? saddr->sll_addr : NULL;
                dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
                if (addr && dev && saddr->sll_halen < dev->addr_len)
                        goto out;
@@ -2436,7 +2436,7 @@ static int packet_snd(struct socket *soc
                if (msg->msg_namelen < (saddr->sll_halen + offsetof(struct 
sockaddr_ll, sll_addr)))
                        goto out;
                proto   = saddr->sll_protocol;
-               addr    = saddr->sll_addr;
+               addr    = saddr->sll_halen ? saddr->sll_addr : NULL;
                dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex);
                if (addr && dev && saddr->sll_halen < dev->addr_len)
                        goto out;