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.
[Backport of net-next 0f85feae6b710ced3abad5b2b47d31dfcb956b62]
Bug: 16355602
Change-Id: Ibe1def7979625ee7902bff2f33ec8945b9945948
Reported-by: Dann Frazier <dann.frazier@canonical.com>
Bisected-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: ca777eff51f7 ("tcp: remove dst refcount false sharing for prequeue mode")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kevin F. Haggerty <haggertk@lineageos.org>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index b5821fa..64bef05 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -627,6 +627,7 @@
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) {
@@ -637,7 +638,7 @@
* 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)->daddr,
ntohs(th->source), inet_iif(skb));
/* don't send rst if it can't find key */
@@ -684,7 +685,6 @@
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_reply(net->ipv4.tcp_sock, skb, ip_hdr(skb)->saddr,
&arg, arg.iov[0].iov_len);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 7f995b4..d9224e7 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -831,14 +831,15 @@
return tcp_gro_complete(skb);
}
-static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
- u32 ts, struct tcp_md5sig_key *key, int rst, u8 tclass)
+static void tcp_v6_send_response(struct sock *sk, struct sk_buff *skb, u32 seq,
+ u32 ack, u32 win, u32 ts,
+ struct tcp_md5sig_key *key, int rst, u8 tclass)
{
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;
@@ -979,7 +980,7 @@
ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
(th->doff << 2);
- tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1, 0);
+ tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, key, 1, 0);
#ifdef CONFIG_TCP_MD5SIG
release_sk1:
@@ -990,10 +991,11 @@
#endif
}
-static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,
+static void tcp_v6_send_ack(struct sock *sk, struct sk_buff *skb,
+ u32 seq, u32 ack, u32 win, u32 ts,
struct tcp_md5sig_key *key, u8 tclass)
{
- tcp_v6_send_response(skb, seq, ack, win, ts, key, 0, tclass);
+ tcp_v6_send_response(sk, skb, seq, ack, win, ts, key, 0, tclass);
}
static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
@@ -1001,7 +1003,7 @@
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,
tcptw->tw_ts_recent, tcp_twsk_md5_key(tcptw),
tw->tw_tclass);
@@ -1012,7 +1014,7 @@
static void tcp_v6_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
struct request_sock *req)
{
- tcp_v6_send_ack(skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
+ tcp_v6_send_ack(sk, skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent,
tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->daddr), 0);
}