dccp: fix freeing skb too early for IPV6_RECVPKTINFO

[firefly-linux-kernel-4.4.55.git] / net / dccp / ipv4.c

diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 5684e14932bd47e97b9d547307bfc50230e7be7d..0759f5b9180e56056d2a365c58ef7aa49a7567e5 100644 (file)
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -204,8 +204,6 @@ void dccp_req_err(struct sock *sk, u64 seq)
         * ICMPs are not backlogged, hence we cannot get an established
         * socket here.
         */
-       WARN_ON(req->sk);
-
        if (!between48(seq, dccp_rsk(req)->dreq_iss, dccp_rsk(req)->dreq_gss)) {
                NET_INC_STATS_BH(net, LINUX_MIB_OUTOFWINDOWICMPS);
        } else {
@@ -237,7 +235,7 @@ static void dccp_v4_err(struct sk_buff *skb, u32 info)
 {
        const struct iphdr *iph = (struct iphdr *)skb->data;
        const u8 offset = iph->ihl << 2;
-       const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
+       const struct dccp_hdr *dh;
        struct dccp_sock *dp;
        struct inet_sock *inet;
        const int type = icmp_hdr(skb)->type;
@@ -247,11 +245,13 @@ static void dccp_v4_err(struct sk_buff *skb, u32 info)
        int err;
        struct net *net = dev_net(skb->dev);
 
-       if (skb->len < offset + sizeof(*dh) ||
-           skb->len < offset + __dccp_basic_hdr_len(dh)) {
-               ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
-               return;
-       }
+       /* Only need dccph_dport & dccph_sport which are the first
+        * 4 bytes in dccp header.
+        * Our caller (icmp_socket_deliver()) already pulled 8 bytes for us.
+        */
+       BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8);
+       BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8);
+       dh = (struct dccp_hdr *)(skb->data + offset);
 
        sk = __inet_lookup_established(net, &dccp_hashinfo,
                                       iph->daddr, dh->dccph_dport,
@@ -698,6 +698,7 @@ int dccp_invalid_packet(struct sk_buff *skb)
 {
        const struct dccp_hdr *dh;
        unsigned int cscov;
+       u8 dccph_doff;
 
        if (skb->pkt_type != PACKET_HOST)
                return 1;
@@ -719,18 +720,19 @@ int dccp_invalid_packet(struct sk_buff *skb)
        /*
         * If P.Data Offset is too small for packet type, drop packet and return
         */
-       if (dh->dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
-               DCCP_WARN("P.Data Offset(%u) too small\n", dh->dccph_doff);
+       dccph_doff = dh->dccph_doff;
+       if (dccph_doff < dccp_hdr_len(skb) / sizeof(u32)) {
+               DCCP_WARN("P.Data Offset(%u) too small\n", dccph_doff);
                return 1;
        }
        /*
         * If P.Data Offset is too too large for packet, drop packet and return
         */
-       if (!pskb_may_pull(skb, dh->dccph_doff * sizeof(u32))) {
-               DCCP_WARN("P.Data Offset(%u) too large\n", dh->dccph_doff);
+       if (!pskb_may_pull(skb, dccph_doff * sizeof(u32))) {
+               DCCP_WARN("P.Data Offset(%u) too large\n", dccph_doff);
                return 1;
        }
-
+       dh = dccp_hdr(skb);
        /*
         * If P.type is not Data, Ack, or DataAck and P.X == 0 (the packet
         * has short sequence numbers), drop packet and return
@@ -824,26 +826,26 @@ lookup:
 
        if (sk->sk_state == DCCP_NEW_SYN_RECV) {
                struct request_sock *req = inet_reqsk(sk);
-               struct sock *nsk = NULL;
+               struct sock *nsk;
 
                sk = req->rsk_listener;
-               if (likely(sk->sk_state == DCCP_LISTEN)) {
-                       nsk = dccp_check_req(sk, skb, req);
-               } else {
+               if (unlikely(sk->sk_state != DCCP_LISTEN)) {
                        inet_csk_reqsk_queue_drop_and_put(sk, req);
                        goto lookup;
                }
+               sock_hold(sk);
+               nsk = dccp_check_req(sk, skb, req);
                if (!nsk) {
                        reqsk_put(req);
-                       goto discard_it;
+                       goto discard_and_relse;
                }
                if (nsk == sk) {
-                       sock_hold(sk);
                        reqsk_put(req);
                } else if (dccp_child_process(sk, nsk, skb)) {
                        dccp_v4_ctl_send_reset(sk, skb);
-                       goto discard_it;
+                       goto discard_and_relse;
                } else {
+                       sock_put(sk);
                        return 0;
                }
        }