From b2cf86e1563e33a14a1c69b3e508d15dc12f804c Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 29 Apr 2019 11:46:55 -0400 Subject: packet: in recvmsg msg_name return at least sizeof sockaddr_ll Packet send checks that msg_name is at least sizeof sockaddr_ll. Packet recv must return at least this length, so that its output can be passed unmodified to packet send. This ceased to be true since adding support for lladdr longer than sll_addr. Since, the return value uses true address length. Always return at least sizeof sockaddr_ll, even if address length is shorter. Zero the padding bytes. Change v1->v2: do not overwrite zeroed padding again. use copy_len. Fixes: 0fb375fb9b93 ("[AF_PACKET]: Allow for > 8 byte hardware addresses.") Suggested-by: David Laight Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/packet/af_packet.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'net/packet') diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 9419c5cf4de5..7d361cd53ad5 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3344,20 +3344,29 @@ static int packet_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, sock_recv_ts_and_drops(msg, sk, skb); if (msg->msg_name) { + int copy_len; + /* If the address length field is there to be filled * in, we fill it in now. */ if (sock->type == SOCK_PACKET) { __sockaddr_check_size(sizeof(struct sockaddr_pkt)); msg->msg_namelen = sizeof(struct sockaddr_pkt); + copy_len = msg->msg_namelen; } else { struct sockaddr_ll *sll = &PACKET_SKB_CB(skb)->sa.ll; msg->msg_namelen = sll->sll_halen + offsetof(struct sockaddr_ll, sll_addr); + copy_len = msg->msg_namelen; + if (msg->msg_namelen < sizeof(struct sockaddr_ll)) { + memset(msg->msg_name + + offsetof(struct sockaddr_ll, sll_addr), + 0, sizeof(sll->sll_addr)); + msg->msg_namelen = sizeof(struct sockaddr_ll); + } } - memcpy(msg->msg_name, &PACKET_SKB_CB(skb)->sa, - msg->msg_namelen); + memcpy(msg->msg_name, &PACKET_SKB_CB(skb)->sa, copy_len); } if (pkt_sk(sk)->auxdata) { -- cgit v1.2.3-59-g8ed1b From 486efdc8f6ce802b27e15921d2353cc740c55451 Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 29 Apr 2019 11:53:18 -0400 Subject: packet: validate msg_namelen in send directly 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 Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- net/packet/af_packet.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) (limited to 'net/packet') diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 7d361cd53ad5..9b81813dd16a 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; -- cgit v1.2.3-59-g8ed1b