net/dccp: fix use after free in tw_timer_handler()

[pandora-kernel.git] / net / dccp / ipv6.c

diff --git a/net/dccp/ipv6.c b/net/dccp/ipv6.c
index 17ee85c..61716f6 100644 (file)
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
@@ -83,7 +83,7 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
                        u8 type, u8 code, int offset, __be32 info)
 {
        const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data;
-       const struct dccp_hdr *dh = (struct dccp_hdr *)(skb->data + offset);
+       const struct dccp_hdr *dh;
        struct dccp_sock *dp;
        struct ipv6_pinfo *np;
        struct sock *sk;
@@ -91,12 +91,13 @@ static void dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
        __u64 seq;
        struct net *net = dev_net(skb->dev);
 
-       if (skb->len < offset + sizeof(*dh) ||
-           skb->len < offset + __dccp_basic_hdr_len(dh)) {
-               ICMP6_INC_STATS_BH(net, __in6_dev_get(skb->dev),
-                                  ICMP6_MIB_INERRORS);
-               return;
-       }
+       /* Only need dccph_dport & dccph_sport which are the first
+        * 4 bytes in dccp header.
+        * Our caller (icmpv6_notify()) already pulled 8 bytes for us.
+        */
+       BUILD_BUG_ON(offsetof(struct dccp_hdr, dccph_sport) + sizeof(dh->dccph_sport) > 8);
+       BUILD_BUG_ON(offsetof(struct dccp_hdr, dccph_dport) + sizeof(dh->dccph_dport) > 8);
+       dh = (struct dccp_hdr *)(skb->data + offset);
 
        sk = inet6_lookup(net, &dccp_hashinfo,
                        &hdr->daddr, dh->dccph_dport,
@@ -236,7 +237,6 @@ static int dccp_v6_send_response(struct sock *sk, struct request_sock *req,
        struct inet6_request_sock *ireq6 = inet6_rsk(req);
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct sk_buff *skb;
-       struct ipv6_txoptions *opt = NULL;
        struct in6_addr *final_p, final;
        struct flowi6 fl6;
        int err = -1;
@@ -252,9 +252,10 @@ static int dccp_v6_send_response(struct sock *sk, struct request_sock *req,
        fl6.fl6_sport = inet_rsk(req)->loc_port;
        security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 
-       opt = np->opt;
 
-       final_p = fl6_update_dst(&fl6, opt, &final);
+       rcu_read_lock();
+       final_p = fl6_update_dst(&fl6, rcu_dereference(np->opt), &final);
+       rcu_read_unlock();
 
        dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
        if (IS_ERR(dst)) {
@@ -271,13 +272,14 @@ static int dccp_v6_send_response(struct sock *sk, struct request_sock *req,
                                                         &ireq6->loc_addr,
                                                         &ireq6->rmt_addr);
                ipv6_addr_copy(&fl6.daddr, &ireq6->rmt_addr);
-               err = ip6_xmit(sk, skb, &fl6, opt, np->tclass);
+               rcu_read_lock();
+               err = ip6_xmit(sk, skb, &fl6, rcu_dereference(np->opt),
+                              np->tclass);
+               rcu_read_unlock();
                err = net_xmit_eval(err);
        }
 
 done:
-       if (opt != NULL && opt != np->opt)
-               sock_kfree_s(sk, opt, opt->tot_len);
        dst_release(dst);
        return err;
 }
@@ -467,10 +469,10 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
 {
        struct inet6_request_sock *ireq6 = inet6_rsk(req);
        struct ipv6_pinfo *newnp, *np = inet6_sk(sk);
+       struct ipv6_txoptions *opt;
        struct inet_sock *newinet;
        struct dccp6_sock *newdp6;
        struct sock *newsk;
-       struct ipv6_txoptions *opt;
 
        if (skb->protocol == htons(ETH_P_IP)) {
                /*
@@ -515,7 +517,6 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
                return newsk;
        }
 
-       opt = np->opt;
 
        if (sk_acceptq_is_full(sk))
                goto out_overflow;
@@ -527,7 +528,7 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
                memset(&fl6, 0, sizeof(fl6));
                fl6.flowi6_proto = IPPROTO_DCCP;
                ipv6_addr_copy(&fl6.daddr, &ireq6->rmt_addr);
-               final_p = fl6_update_dst(&fl6, opt, &final);
+               final_p = fl6_update_dst(&fl6, np->opt, &final);
                ipv6_addr_copy(&fl6.saddr, &ireq6->loc_addr);
                fl6.flowi6_oif = sk->sk_bound_dev_if;
                fl6.fl6_dport = inet_rsk(req)->rmt_port;
@@ -592,16 +593,15 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
         * Yes, keeping reference count would be much more clever, but we make
         * one more one thing there: reattach optmem to newsk.
         */
-       if (opt != NULL) {
-               newnp->opt = ipv6_dup_options(newsk, opt);
-               if (opt != np->opt)
-                       sock_kfree_s(sk, opt, opt->tot_len);
+       opt = rcu_dereference(np->opt);
+       if (opt) {
+               opt = ipv6_dup_options(newsk, opt);
+               RCU_INIT_POINTER(newnp->opt, opt);
        }
-
        inet_csk(newsk)->icsk_ext_hdr_len = 0;
-       if (newnp->opt != NULL)
-               inet_csk(newsk)->icsk_ext_hdr_len = (newnp->opt->opt_nflen +
-                                                    newnp->opt->opt_flen);
+       if (opt)
+               inet_csk(newsk)->icsk_ext_hdr_len = opt->opt_nflen +
+                                                   opt->opt_flen;
 
        dccp_sync_mss(newsk, dst_mtu(dst));
 
@@ -609,7 +609,8 @@ static struct sock *dccp_v6_request_recv_sock(struct sock *sk,
        newinet->inet_rcv_saddr = LOOPBACK4_IPV6;
 
        if (__inet_inherit_port(sk, newsk) < 0) {
-               sock_put(newsk);
+               inet_csk_prepare_forced_close(newsk);
+               dccp_done(newsk);
                goto out;
        }
        __inet6_hash(newsk, NULL);
@@ -622,8 +623,6 @@ out_nonewsk:
        dst_release(dst);
 out:
        NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_LISTENDROPS);
-       if (opt != NULL && opt != np->opt)
-               sock_kfree_s(sk, opt, opt->tot_len);
        return NULL;
 }
 
@@ -819,7 +818,7 @@ static int dccp_v6_rcv(struct sk_buff *skb)
        if (!xfrm6_policy_check(sk, XFRM_POLICY_IN, skb))
                goto discard_and_relse;
 
-       return sk_receive_skb(sk, skb, 1) ? -1 : 0;
+       return __sk_receive_skb(sk, skb, 1, dh->dccph_doff * 4) ? -1 : 0;
 
 no_dccp_socket:
        if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb))
@@ -854,6 +853,7 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct dccp_sock *dp = dccp_sk(sk);
        struct in6_addr *saddr = NULL, *final_p, final;
+       struct ipv6_txoptions *opt;
        struct flowi6 fl6;
        struct dst_entry *dst;
        int addr_type;
@@ -956,7 +956,8 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
        fl6.fl6_sport = inet->inet_sport;
        security_sk_classify_flow(sk, flowi6_to_flowi(&fl6));
 
-       final_p = fl6_update_dst(&fl6, np->opt, &final);
+       opt = rcu_dereference_protected(np->opt, sock_owned_by_user(sk));
+       final_p = fl6_update_dst(&fl6, opt, &final);
 
        dst = ip6_dst_lookup_flow(sk, &fl6, final_p, true);
        if (IS_ERR(dst)) {
@@ -976,9 +977,8 @@ static int dccp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
        __ip6_dst_store(sk, dst, NULL, NULL);
 
        icsk->icsk_ext_hdr_len = 0;
-       if (np->opt != NULL)
-               icsk->icsk_ext_hdr_len = (np->opt->opt_flen +
-                                         np->opt->opt_nflen);
+       if (opt)
+               icsk->icsk_ext_hdr_len = opt->opt_flen + opt->opt_nflen;
 
        inet->inet_dport = usin->sin6_port;
 
@@ -1038,6 +1038,7 @@ static const struct inet_connection_sock_af_ops dccp_ipv6_mapped = {
        .getsockopt        = ipv6_getsockopt,
        .addr2sockaddr     = inet6_csk_addr2sockaddr,
        .sockaddr_len      = sizeof(struct sockaddr_in6),
+       .bind_conflict     = inet6_csk_bind_conflict,
 #ifdef CONFIG_COMPAT
        .compat_setsockopt = compat_ipv6_setsockopt,
        .compat_getsockopt = compat_ipv6_getsockopt,
@@ -1156,9 +1157,15 @@ static void __net_exit dccp_v6_exit_net(struct net *net)
        inet_ctl_sock_destroy(net->dccp.v6_ctl_sk);
 }
 
+static void __net_exit dccp_v6_exit_batch(struct list_head *net_exit_list)
+{
+       inet_twsk_purge(&dccp_hashinfo, &dccp_death_row, AF_INET6);
+}
+
 static struct pernet_operations dccp_v6_ops = {
        .init   = dccp_v6_init_net,
        .exit   = dccp_v6_exit_net,
+       .exit_batch = dccp_v6_exit_batch,
 };
 
 static int __init dccp_v6_init(void)