[PATCH 5.0 14/32] packet: validate msg_namelen in send directly

Greg Kroah-Hartman
2019-05-04T10:25:53Z

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

[ Upstream commit 486efdc8f6ce802b27e15921d2353cc740c55451 ]

Packet sockets in datagram mode take a destination address. Verify its
length before passing to dev_hard_header.

Prior to 2.6.14-rc3, the send code ignored sll_halen. This is
established behavior. Directly compare msg_namelen to dev->addr_len.

Change v1->v2: initialize addr in all paths

Fixes: 6b8d95f1795c4 ("packet: validate address length if non-zero")
Suggested-by: David Laight <David.Laight@aculab.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>
---
net/packet/af_packet.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)

--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2603,8 +2603,8 @@ static int tpacket_snd(struct packet_soc
void *ph;
DECLARE_SOCKADDR(struct sockaddr_ll *, saddr, msg->msg_name);
bool need_wait = !(msg->msg_flags & MSG_DONTWAIT);
+ unsigned char *addr = NULL;
int tp_len, size_max;
- unsigned char *addr;
void *data;
int len_sum = 0;
int status = TP_STATUS_AVAILABLE;
@@ -2615,7 +2615,6 @@ static int tpacket_snd(struct packet_soc
if (likely(saddr == NULL)) {
dev = packet_cached_dev_get(po);
proto = po->num;
- addr = NULL;
} else {
err = -EINVAL;
if (msg->msg_namelen < sizeof(struct sockaddr_ll))
@@ -2625,10 +2624,13 @@ static int tpacket_snd(struct packet_soc
sll_addr)))
goto out;
proto = saddr->sll_protocol;
- 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_put;
+ if (po->sk.sk_socket->type == SOCK_DGRAM) {
+ if (dev && msg->msg_namelen < dev->addr_len +
+ offsetof(struct sockaddr_ll, sll_addr))
+ goto out_put;
+ addr = saddr->sll_addr;
+ }
}

err = -ENXIO;
@@ -2800,7 +2802,7 @@ static int packet_snd(struct socket *soc
struct sk_buff *skb;
struct net_device *dev;
__be16 proto;
- unsigned char *addr;
+ unsigned char *addr = NULL;
int err, reserve = 0;
struct sockcm_cookie sockc;
struct virtio_net_hdr vnet_hdr = { 0 };
@@ -2817,7 +2819,6 @@ static int packet_snd(struct socket *soc
if (likely(saddr == NULL)) {
dev = packet_cached_dev_get(po);
proto = po->num;
- addr = NULL;
} else {
err = -EINVAL;
if (msg->msg_namelen < sizeof(struct sockaddr_ll))
@@ -2825,10 +2826,13 @@ 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_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_unlock;
+ if (sock->type == SOCK_DGRAM) {
+ if (dev && msg->msg_namelen < dev->addr_len +
+ offsetof(struct sockaddr_ll, sll_addr))
+ goto out_unlock;
+ addr = saddr->sll_addr;
+ }
}

err = -ENXIO;