From: Willem de Bruijn
> Sent: 29 April 2019 16:53
> 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.lai...@aculab.com>
> Signed-off-by: Willem de Bruijn <will...@google.com>
> ---
> net/packet/af_packet.c | 24 ++++++++++++++----------
> 1 file changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 9419c5cf4de5e..a43876b374da2 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -2602,8 +2602,8 @@ static int tpacket_snd(struct packet_sock *po, struct
> msghdr *msg)
> 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;
> @@ -2614,7 +2614,6 @@ static int tpacket_snd(struct packet_sock *po, struct
> msghdr *msg)
> 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))
> @@ -2624,10 +2623,13 @@ static int tpacket_snd(struct packet_sock *po, struct
> msghdr *msg)
> 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;
> @@ -2799,7 +2801,7 @@ static int packet_snd(struct socket *sock, struct
> msghdr *msg, size_t len)
> 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 };
> @@ -2816,7 +2818,6 @@ static int packet_snd(struct socket *sock, struct
> msghdr *msg, size_t len)
> 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))
> @@ -2824,10 +2825,13 @@ 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_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;
> --
> 2.21.0.593.g511ec345e18-goog
LGTM
David
-
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UK
Registration No: 1397386 (Wales)
