packet: validate address length if non-zero

BugLink: https://bugs.launchpad.net/bugs/1837257
[ 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 <idosch@idosch.org>
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>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index c8508721f34a59383738d315d760d5d06fd289f6..a17fc9574d1894f5dc501ae7ca1f35257dc50b44 100644 (file)
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2653,7 +2653,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
                                                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;
@@ -2853,7 +2853,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
                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;