From 0f85feae6b710ced3abad5b2b47d31dfcb956b62 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 9 Dec 2014 09:56:08 -0800 Subject: [PATCH] tcp: fix more NULL deref after prequeue changes When I cooked commit c3658e8d0f1 ("tcp: fix possible NULL dereference in tcp_vX_send_reset()") I missed other spots we could deref a NULL skb_dst(skb) Again, if a socket is provided, we do not need skb_dst() to get a pointer to network namespace : sock_net(sk) is good enough. Reported-by: Dann Frazier Bisected-by: Dann Frazier Tested-by: Dann Frazier Signed-off-by: Eric Dumazet Fixes: ca777eff51f7 ("tcp: remove dst refcount false sharing for prequeue mode") Signed-off-by: David S. Miller --- net/ipv4/tcp_ipv4.c | 4 ++-- net/ipv6/tcp_ipv6.c | 28 ++++++++++++++-------------- 2 files changed, 16 insertions(+), 16 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 147be2024290..ef7089ca86e2 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -623,6 +623,7 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) arg.iov[0].iov_base = (unsigned char *)&rep; arg.iov[0].iov_len = sizeof(rep.th); + net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); #ifdef CONFIG_TCP_MD5SIG hash_location = tcp_parse_md5sig_option(th); if (!sk && hash_location) { @@ -633,7 +634,7 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) * Incoming packet is checked with md5 hash with finding key, * no RST generated if md5 hash doesn't match. */ - sk1 = __inet_lookup_listener(dev_net(skb_dst(skb)->dev), + sk1 = __inet_lookup_listener(net, &tcp_hashinfo, ip_hdr(skb)->saddr, th->source, ip_hdr(skb)->daddr, ntohs(th->source), inet_iif(skb)); @@ -681,7 +682,6 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb) if (sk) arg.bound_dev_if = sk->sk_bound_dev_if; - net = dev_net(skb_dst(skb)->dev); arg.tos = ip_hdr(skb)->tos; ip_send_unicast_reply(net, skb, &TCP_SKB_CB(skb)->header.h4.opt, ip_hdr(skb)->saddr, ip_hdr(skb)->daddr, diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index dc495ae2ead0..c277951d783b 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -787,16 +787,16 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = { .queue_hash_add = inet6_csk_reqsk_queue_hash_add, }; -static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win, - u32 tsval, u32 tsecr, int oif, - struct tcp_md5sig_key *key, int rst, u8 tclass, - u32 label) +static void tcp_v6_send_response(struct sock *sk, struct sk_buff *skb, u32 seq, + u32 ack, u32 win, u32 tsval, u32 tsecr, + int oif, struct tcp_md5sig_key *key, int rst, + u8 tclass, u32 label) { const struct tcphdr *th = tcp_hdr(skb); struct tcphdr *t1; struct sk_buff *buff; struct flowi6 fl6; - struct net *net = dev_net(skb_dst(skb)->dev); + struct net *net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); struct sock *ctl_sk = net->ipv6.tcp_sk; unsigned int tot_len = sizeof(struct tcphdr); struct dst_entry *dst; @@ -946,7 +946,7 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb) (th->doff << 2); oif = sk ? sk->sk_bound_dev_if : 0; - tcp_v6_send_response(skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0); + tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, 0, 0); #ifdef CONFIG_TCP_MD5SIG release_sk1: @@ -957,13 +957,13 @@ release_sk1: #endif } -static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, - u32 win, u32 tsval, u32 tsecr, int oif, +static void tcp_v6_send_ack(struct sock *sk, struct sk_buff *skb, u32 seq, + u32 ack, u32 win, u32 tsval, u32 tsecr, int oif, struct tcp_md5sig_key *key, u8 tclass, u32 label) { - tcp_v6_send_response(skb, seq, ack, win, tsval, tsecr, oif, key, 0, tclass, - label); + tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0, + tclass, label); } static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) @@ -971,7 +971,7 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) struct inet_timewait_sock *tw = inet_twsk(sk); struct tcp_timewait_sock *tcptw = tcp_twsk(sk); - tcp_v6_send_ack(skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, + tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt, tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale, tcp_time_stamp + tcptw->tw_ts_offset, tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw), @@ -986,10 +986,10 @@ static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb, /* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV * sk->sk_state == TCP_SYN_RECV -> for Fast Open. */ - tcp_v6_send_ack(skb, (sk->sk_state == TCP_LISTEN) ? + tcp_v6_send_ack(sk, skb, (sk->sk_state == TCP_LISTEN) ? tcp_rsk(req)->snt_isn + 1 : tcp_sk(sk)->snd_nxt, - tcp_rsk(req)->rcv_nxt, - req->rcv_wnd, tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if, + tcp_rsk(req)->rcv_nxt, req->rcv_wnd, + tcp_time_stamp, req->ts_recent, sk->sk_bound_dev_if, tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0, 0); } -- 2.20.1