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-rw-r--r--net/ipv4/tcp_ipv4.c45
-rw-r--r--net/ipv6/tcp_ipv6.c43
2 files changed, 83 insertions, 5 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 567cca9b30d..90e47931e21 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -593,6 +593,10 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
struct ip_reply_arg arg;
#ifdef CONFIG_TCP_MD5SIG
struct tcp_md5sig_key *key;
+ const __u8 *hash_location = NULL;
+ unsigned char newhash[16];
+ int genhash;
+ struct sock *sk1 = NULL;
#endif
struct net *net;
@@ -623,9 +627,36 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
arg.iov[0].iov_len = sizeof(rep.th);
#ifdef CONFIG_TCP_MD5SIG
- key = sk ? tcp_md5_do_lookup(sk,
- (union tcp_md5_addr *)&ip_hdr(skb)->saddr,
- AF_INET) : NULL;
+ hash_location = tcp_parse_md5sig_option(th);
+ if (!sk && hash_location) {
+ /*
+ * active side is lost. Try to find listening socket through
+ * source port, and then find md5 key through listening socket.
+ * we are not loose security here:
+ * 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),
+ &tcp_hashinfo, ip_hdr(skb)->daddr,
+ ntohs(th->source), inet_iif(skb));
+ /* don't send rst if it can't find key */
+ if (!sk1)
+ return;
+ rcu_read_lock();
+ key = tcp_md5_do_lookup(sk1, (union tcp_md5_addr *)
+ &ip_hdr(skb)->saddr, AF_INET);
+ if (!key)
+ goto release_sk1;
+
+ genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, NULL, skb);
+ if (genhash || memcmp(hash_location, newhash, 16) != 0)
+ goto release_sk1;
+ } else {
+ key = sk ? tcp_md5_do_lookup(sk, (union tcp_md5_addr *)
+ &ip_hdr(skb)->saddr,
+ AF_INET) : NULL;
+ }
+
if (key) {
rep.opt[0] = htonl((TCPOPT_NOP << 24) |
(TCPOPT_NOP << 16) |
@@ -653,6 +684,14 @@ static void tcp_v4_send_reset(struct sock *sk, struct sk_buff *skb)
TCP_INC_STATS_BH(net, TCP_MIB_OUTSEGS);
TCP_INC_STATS_BH(net, TCP_MIB_OUTRSTS);
+
+#ifdef CONFIG_TCP_MD5SIG
+release_sk1:
+ if (sk1) {
+ rcu_read_unlock();
+ sock_put(sk1);
+ }
+#endif
}
/* The code following below sending ACKs in SYN-RECV and TIME-WAIT states
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index c25018106ef..d16414cb342 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -923,6 +923,13 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
const struct tcphdr *th = tcp_hdr(skb);
u32 seq = 0, ack_seq = 0;
struct tcp_md5sig_key *key = NULL;
+#ifdef CONFIG_TCP_MD5SIG
+ const __u8 *hash_location = NULL;
+ struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+ unsigned char newhash[16];
+ int genhash;
+ struct sock *sk1 = NULL;
+#endif
if (th->rst)
return;
@@ -931,8 +938,32 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
return;
#ifdef CONFIG_TCP_MD5SIG
- if (sk)
- key = tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr);
+ hash_location = tcp_parse_md5sig_option(th);
+ if (!sk && hash_location) {
+ /*
+ * active side is lost. Try to find listening socket through
+ * source port, and then find md5 key through listening socket.
+ * we are not loose security here:
+ * Incoming packet is checked with md5 hash with finding key,
+ * no RST generated if md5 hash doesn't match.
+ */
+ sk1 = inet6_lookup_listener(dev_net(skb_dst(skb)->dev),
+ &tcp_hashinfo, &ipv6h->daddr,
+ ntohs(th->source), inet6_iif(skb));
+ if (!sk1)
+ return;
+
+ rcu_read_lock();
+ key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr);
+ if (!key)
+ goto release_sk1;
+
+ genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, NULL, skb);
+ if (genhash || memcmp(hash_location, newhash, 16) != 0)
+ goto release_sk1;
+ } else {
+ key = sk ? tcp_v6_md5_do_lookup(sk, &ipv6h->saddr) : NULL;
+ }
#endif
if (th->ack)
@@ -942,6 +973,14 @@ static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
(th->doff << 2);
tcp_v6_send_response(skb, seq, ack_seq, 0, 0, key, 1, 0);
+
+#ifdef CONFIG_TCP_MD5SIG
+release_sk1:
+ if (sk1) {
+ rcu_read_unlock();
+ sock_put(sk1);
+ }
+#endif
}
static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts,