[TCP]: MD5 Signature Option (RFC2385) support.

Based on implementation by Rick Payne.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 551 insertions, 17 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 9a88395a7629..663d1d238014 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -66,10 +66,13 @@
 #include <linux/proc_fs.h>
 #include <linux/seq_file.h>
 
+#include <linux/crypto.h>
+#include <linux/scatterlist.h>
+
 /* Socket used for sending RSTs and ACKs */
 static struct socket *tcp6_socket;
 
-static void     tcp_v6_send_reset(struct sk_buff *skb);
+static void     tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb);
 static void     tcp_v6_reqsk_send_ack(struct sk_buff *skb, struct request_sock *req);
 static void     tcp_v6_send_check(struct sock *sk, int len, 
                                   struct sk_buff *skb);
@@ -78,6 +81,8 @@ static int	tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
 
 static struct inet_connection_sock_af_ops ipv6_mapped;
 static struct inet_connection_sock_af_ops ipv6_specific;
+static struct tcp_sock_af_ops tcp_sock_ipv6_specific;
+static struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific;
 
 static int tcp_v6_get_port(struct sock *sk, unsigned short snum)
 {
@@ -208,6 +213,9 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
 
                 icsk->icsk_af_ops = &ipv6_mapped;
                 sk->sk_backlog_rcv = tcp_v4_do_rcv;
+#ifdef CONFIG_TCP_MD5SIG
+                tp->af_specific = &tcp_sock_ipv6_mapped_specific;
+#endif
 
                 err = tcp_v4_connect(sk, (struct sockaddr *)&sin, sizeof(sin));
 
@@ -215,6 +223,9 @@ static int tcp_v6_connect(struct sock *sk, struct sockaddr *uaddr,
                         icsk->icsk_ext_hdr_len = exthdrlen;
                         icsk->icsk_af_ops = &ipv6_specific;
                         sk->sk_backlog_rcv = tcp_v6_do_rcv;
+#ifdef CONFIG_TCP_MD5SIG
+                        tp->af_specific = &tcp_sock_ipv6_specific;
+#endif
                         goto failure;
                 } else {
                         ipv6_addr_set(&np->saddr, 0, 0, htonl(0x0000FFFF),
@@ -518,6 +529,396 @@ static void tcp_v6_reqsk_destructor(struct request_sock *req)
                 kfree_skb(inet6_rsk(req)->pktopts);
 }
 
+#ifdef CONFIG_TCP_MD5SIG
+static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(struct sock *sk,
+                                                   struct in6_addr *addr)
+{
+        struct tcp_sock *tp = tcp_sk(sk);
+        int i;
+
+        BUG_ON(tp == NULL);
+
+        if (!tp->md5sig_info || !tp->md5sig_info->entries6)
+                return NULL;
+
+        for (i = 0; i < tp->md5sig_info->entries6; i++) {
+                if (ipv6_addr_cmp(&tp->md5sig_info->keys6[i].addr, addr) == 0)
+                        return (struct tcp_md5sig_key *)&tp->md5sig_info->keys6[i];
+        }
+        return NULL;
+}
+
+static struct tcp_md5sig_key *tcp_v6_md5_lookup(struct sock *sk,
+                                                struct sock *addr_sk)
+{
+        return tcp_v6_md5_do_lookup(sk, &inet6_sk(addr_sk)->daddr);
+}
+
+static struct tcp_md5sig_key *tcp_v6_reqsk_md5_lookup(struct sock *sk,
+                                                      struct request_sock *req)
+{
+        return tcp_v6_md5_do_lookup(sk, &inet6_rsk(req)->rmt_addr);
+}
+
+static int tcp_v6_md5_do_add(struct sock *sk, struct in6_addr *peer,
+                             char *newkey, u8 newkeylen)
+{
+        /* Add key to the list */
+        struct tcp6_md5sig_key *key;
+        struct tcp_sock *tp = tcp_sk(sk);
+        struct tcp6_md5sig_key *keys;
+
+        key = (struct tcp6_md5sig_key*) tcp_v6_md5_do_lookup(sk, peer);
+        if (key) {
+                /* modify existing entry - just update that one */
+                kfree(key->key);
+                key->key = newkey;
+                key->keylen = newkeylen;
+        } else {
+                /* reallocate new list if current one is full. */
+                if (!tp->md5sig_info) {
+                        tp->md5sig_info = kzalloc(sizeof(*tp->md5sig_info), GFP_ATOMIC);
+                        if (!tp->md5sig_info) {
+                                kfree(newkey);
+                                return -ENOMEM;
+                        }
+                }
+                tcp_alloc_md5sig_pool();
+                if (tp->md5sig_info->alloced6 == tp->md5sig_info->entries6) {
+                        keys = kmalloc((sizeof (tp->md5sig_info->keys6[0]) *
+                                       (tp->md5sig_info->entries6 + 1)), GFP_ATOMIC);
+
+                        if (!keys) {
+                                tcp_free_md5sig_pool();
+                                kfree(newkey);
+                                return -ENOMEM;
+                        }
+
+                        if (tp->md5sig_info->entries6)
+                                memmove(keys, tp->md5sig_info->keys6,
+                                        (sizeof (tp->md5sig_info->keys6[0]) *
+                                         tp->md5sig_info->entries6));
+
+                        kfree(tp->md5sig_info->keys6);
+                        tp->md5sig_info->keys6 = keys;
+                        tp->md5sig_info->alloced6++;
+                }
+
+                ipv6_addr_copy(&tp->md5sig_info->keys6[tp->md5sig_info->entries6].addr,
+                               peer);
+                tp->md5sig_info->keys6[tp->md5sig_info->entries6].key = newkey;
+                tp->md5sig_info->keys6[tp->md5sig_info->entries6].keylen = newkeylen;
+
+                tp->md5sig_info->entries6++;
+        }
+        return 0;
+}
+
+static int tcp_v6_md5_add_func(struct sock *sk, struct sock *addr_sk,
+                               u8 *newkey, __u8 newkeylen)
+{
+        return tcp_v6_md5_do_add(sk, &inet6_sk(addr_sk)->daddr,
+                                 newkey, newkeylen);
+}
+
+static int tcp_v6_md5_do_del(struct sock *sk, struct in6_addr *peer)
+{
+        struct tcp_sock *tp = tcp_sk(sk);
+        int i;
+
+        for (i = 0; i < tp->md5sig_info->entries6; i++) {
+                if (ipv6_addr_cmp(&tp->md5sig_info->keys6[i].addr, peer) == 0) {
+                        /* Free the key */
+                        kfree(tp->md5sig_info->keys6[i].key);
+                        tp->md5sig_info->entries6--;
+
+                        if (tp->md5sig_info->entries6 == 0) {
+                                kfree(tp->md5sig_info->keys6);
+                                tp->md5sig_info->keys6 = NULL;
+
+                                tcp_free_md5sig_pool();
+
+                                return 0;
+                        } else {
+                                /* shrink the database */
+                                if (tp->md5sig_info->entries6 != i)
+                                        memmove(&tp->md5sig_info->keys6[i],
+                                                &tp->md5sig_info->keys6[i+1],
+                                                (tp->md5sig_info->entries6 - i)
+                                                * sizeof (tp->md5sig_info->keys6[0]));
+                        }
+                }
+        }
+        return -ENOENT;
+}
+
+static void tcp_v6_clear_md5_list (struct sock *sk)
+{
+        struct tcp_sock *tp = tcp_sk(sk);
+        int i;
+
+        if (tp->md5sig_info->entries6) {
+                for (i = 0; i < tp->md5sig_info->entries6; i++)
+                        kfree(tp->md5sig_info->keys6[i].key);
+                tp->md5sig_info->entries6 = 0;
+                tcp_free_md5sig_pool();
+        }
+
+        kfree(tp->md5sig_info->keys6);
+        tp->md5sig_info->keys6 = NULL;
+        tp->md5sig_info->alloced6 = 0;
+
+        if (tp->md5sig_info->entries4) {
+                for (i = 0; i < tp->md5sig_info->entries4; i++)
+                        kfree(tp->md5sig_info->keys4[i].key);
+                tp->md5sig_info->entries4 = 0;
+                tcp_free_md5sig_pool();
+        }
+
+        kfree(tp->md5sig_info->keys4);
+        tp->md5sig_info->keys4 = NULL;
+        tp->md5sig_info->alloced4 = 0;
+}
+
+static int tcp_v6_parse_md5_keys (struct sock *sk, char __user *optval,
+                                  int optlen)
+{
+        struct tcp_md5sig cmd;
+        struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr;
+        u8 *newkey;
+
+        if (optlen < sizeof(cmd))
+                return -EINVAL;
+
+        if (copy_from_user(&cmd, optval, sizeof(cmd)))
+                return -EFAULT;
+
+        if (sin6->sin6_family != AF_INET6)
+                return -EINVAL;
+
+        if (!cmd.tcpm_keylen) {
+                if (!tcp_sk(sk)->md5sig_info)
+                        return -ENOENT;
+                if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_MAPPED)
+                        return tcp_v4_md5_do_del(sk, sin6->sin6_addr.s6_addr32[3]);
+                return tcp_v6_md5_do_del(sk, &sin6->sin6_addr);
+        }
+
+        if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN)
+                return -EINVAL;
+
+        if (!tcp_sk(sk)->md5sig_info) {
+                struct tcp_sock *tp = tcp_sk(sk);
+                struct tcp_md5sig_info *p;
+
+                p = kzalloc(sizeof(struct tcp_md5sig_info), GFP_KERNEL);
+                if (!p)
+                        return -ENOMEM;
+
+                tp->md5sig_info = p;
+        }
+
+        newkey = kmalloc(cmd.tcpm_keylen, GFP_KERNEL);
+        if (!newkey)
+                return -ENOMEM;
+        memcpy(newkey, cmd.tcpm_key, cmd.tcpm_keylen);
+        if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_MAPPED) {
+                return tcp_v4_md5_do_add(sk, sin6->sin6_addr.s6_addr32[3],
+                                         newkey, cmd.tcpm_keylen);
+        }
+        return tcp_v6_md5_do_add(sk, &sin6->sin6_addr, newkey, cmd.tcpm_keylen);
+}
+
+static int tcp_v6_do_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
+                                   struct in6_addr *saddr,
+                                   struct in6_addr *daddr,
+                                   struct tcphdr *th, int protocol,
+                                   int tcplen)
+{
+        struct scatterlist sg[4];
+        __u16 data_len;
+        int block = 0;
+        __u16 cksum;
+        struct tcp_md5sig_pool *hp;
+        struct tcp6_pseudohdr *bp;
+        struct hash_desc *desc;
+        int err;
+        unsigned int nbytes = 0;
+
+        hp = tcp_get_md5sig_pool();
+        if (!hp) {
+                printk(KERN_WARNING "%s(): hash pool not found...\n", __FUNCTION__);
+                goto clear_hash_noput;
+        }
+        bp = &hp->md5_blk.ip6;
+        desc = &hp->md5_desc;
+
+        /* 1. TCP pseudo-header (RFC2460) */
+        ipv6_addr_copy(&bp->saddr, saddr);
+        ipv6_addr_copy(&bp->daddr, daddr);
+        bp->len = htonl(tcplen);
+        bp->protocol = htonl(protocol);
+
+        sg_set_buf(&sg[block++], bp, sizeof(*bp));
+        nbytes += sizeof(*bp);
+
+        /* 2. TCP header, excluding options */
+        cksum = th->check;
+        th->check = 0;
+        sg_set_buf(&sg[block++], th, sizeof(*th));
+        nbytes += sizeof(*th);
+
+        /* 3. TCP segment data (if any) */
+        data_len = tcplen - (th->doff << 2);
+        if (data_len > 0) {
+                u8 *data = (u8 *)th + (th->doff << 2);
+                sg_set_buf(&sg[block++], data, data_len);
+                nbytes += data_len;
+        }
+
+        /* 4. shared key */
+        sg_set_buf(&sg[block++], key->key, key->keylen);
+        nbytes += key->keylen;
+
+        /* Now store the hash into the packet */
+        err = crypto_hash_init(desc);
+        if (err) {
+                printk(KERN_WARNING "%s(): hash_init failed\n", __FUNCTION__);
+                goto clear_hash;
+        }
+        err = crypto_hash_update(desc, sg, nbytes);
+        if (err) {
+                printk(KERN_WARNING "%s(): hash_update failed\n", __FUNCTION__);
+                goto clear_hash;
+        }
+        err = crypto_hash_final(desc, md5_hash);
+        if (err) {
+                printk(KERN_WARNING "%s(): hash_final failed\n", __FUNCTION__);
+                goto clear_hash;
+        }
+
+        /* Reset header, and free up the crypto */
+        tcp_put_md5sig_pool();
+        th->check = cksum;
+out:
+        return 0;
+clear_hash:
+        tcp_put_md5sig_pool();
+clear_hash_noput:
+        memset(md5_hash, 0, 16);
+        goto out;
+}
+
+static int tcp_v6_calc_md5_hash(char *md5_hash, struct tcp_md5sig_key *key,
+                                struct sock *sk,
+                                struct dst_entry *dst,
+                                struct request_sock *req,
+                                struct tcphdr *th, int protocol,
+                                int tcplen)
+{
+        struct in6_addr *saddr, *daddr;
+
+        if (sk) {
+                saddr = &inet6_sk(sk)->saddr;
+                daddr = &inet6_sk(sk)->daddr;
+        } else {
+                saddr = &inet6_rsk(req)->loc_addr;
+                daddr = &inet6_rsk(req)->rmt_addr;
+        }
+        return tcp_v6_do_calc_md5_hash(md5_hash, key,
+                                       saddr, daddr,
+                                       th, protocol, tcplen);
+}
+
+static int tcp_v6_inbound_md5_hash (struct sock *sk, struct sk_buff *skb)
+{
+        __u8 *hash_location = NULL;
+        struct tcp_md5sig_key *hash_expected;
+        struct ipv6hdr *ip6h = skb->nh.ipv6h;
+        struct tcphdr *th = skb->h.th;
+        int length = (th->doff << 2) - sizeof (*th);
+        int genhash;
+        u8 *ptr;
+        u8 newhash[16];
+
+        hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
+
+        /* If the TCP option is too short, we can short cut */
+        if (length < TCPOLEN_MD5SIG)
+                return hash_expected ? 1 : 0;
+
+        /* parse options */
+        ptr = (u8*)(th + 1);
+        while (length > 0) {
+                int opcode = *ptr++;
+                int opsize;
+
+                switch(opcode) {
+                case TCPOPT_EOL:
+                        goto done_opts;
+                case TCPOPT_NOP:
+                        length--;
+                        continue;
+                default:
+                        opsize = *ptr++;
+                        if (opsize < 2 || opsize > length)
+                                goto done_opts;
+                        if (opcode == TCPOPT_MD5SIG) {
+                                hash_location = ptr;
+                                goto done_opts;
+                        }
+                }
+                ptr += opsize - 2;
+                length -= opsize;
+        }
+
+done_opts:
+        /* do we have a hash as expected? */
+        if (!hash_expected) {
+                if (!hash_location)
+                        return 0;
+                if (net_ratelimit()) {
+                        printk(KERN_INFO "MD5 Hash NOT expected but found "
+                               "(" NIP6_FMT ", %u)->"
+                               "(" NIP6_FMT ", %u)\n",
+                               NIP6(ip6h->saddr), ntohs(th->source),
+                               NIP6(ip6h->daddr), ntohs(th->dest));
+                }
+                return 1;
+        }
+
+        if (!hash_location) {
+                if (net_ratelimit()) {
+                        printk(KERN_INFO "MD5 Hash expected but NOT found "
+                               "(" NIP6_FMT ", %u)->"
+                               "(" NIP6_FMT ", %u)\n",
+                               NIP6(ip6h->saddr), ntohs(th->source),
+                               NIP6(ip6h->daddr), ntohs(th->dest));
+                }
+                return 1;
+        }
+
+        /* check the signature */
+        genhash = tcp_v6_do_calc_md5_hash(newhash,
+                                          hash_expected,
+                                          &ip6h->saddr, &ip6h->daddr,
+                                          th, sk->sk_protocol,
+                                          skb->len);
+        if (genhash || memcmp(hash_location, newhash, 16) != 0) {
+                if (net_ratelimit()) {
+                        printk(KERN_INFO "MD5 Hash %s for "
+                               "(" NIP6_FMT ", %u)->"
+                               "(" NIP6_FMT ", %u)\n",
+                               genhash ? "failed" : "mismatch",
+                               NIP6(ip6h->saddr), ntohs(th->source),
+                               NIP6(ip6h->daddr), ntohs(th->dest));
+                }
+                return 1;
+        }
+        return 0;
+}
+#endif
+
 static struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
         .family         =       AF_INET6,
         .obj_size       =       sizeof(struct tcp6_request_sock),
@@ -527,9 +928,16 @@ static struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
         .send_reset     =       tcp_v6_send_reset
 };
 
+struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
+#ifdef CONFIG_TCP_MD5SIG
+        .md5_lookup     =       tcp_v6_reqsk_md5_lookup,
+#endif
+};
+
 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
         .twsk_obj_size  = sizeof(struct tcp6_timewait_sock),
         .twsk_unique    = tcp_twsk_unique,
+        .twsk_destructor= tcp_twsk_destructor,
 };
 
 static void tcp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb)
@@ -566,11 +974,15 @@ static int tcp_v6_gso_send_check(struct sk_buff *skb)
         return 0;
 }
 
-static void tcp_v6_send_reset(struct sk_buff *skb)
+static void tcp_v6_send_reset(struct sock *sk, struct sk_buff *skb)
 {
         struct tcphdr *th = skb->h.th, *t1; 
         struct sk_buff *buff;
         struct flowi fl;
+        int tot_len = sizeof(*th);
+#ifdef CONFIG_TCP_MD5SIG
+        struct tcp_md5sig_key *key;
+#endif
 
         if (th->rst)
                 return;
@@ -578,25 +990,35 @@ static void tcp_v6_send_reset(struct sk_buff *skb)
         if (!ipv6_unicast_destination(skb))
                 return; 
 
+#ifdef CONFIG_TCP_MD5SIG
+        if (sk)
+                key = tcp_v6_md5_do_lookup(sk, &skb->nh.ipv6h->daddr);
+        else
+                key = NULL;
+
+        if (key)
+                tot_len += TCPOLEN_MD5SIG_ALIGNED;
+#endif
+
         /*
          * We need to grab some memory, and put together an RST,
          * and then put it into the queue to be sent.
          */
 
-        buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + sizeof(struct tcphdr),
+        buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
                          GFP_ATOMIC);
         if (buff == NULL) 
                 return;
 
-        skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + sizeof(struct tcphdr));
+        skb_reserve(buff, MAX_HEADER + sizeof(struct ipv6hdr) + tot_len);
 
-        t1 = (struct tcphdr *) skb_push(buff,sizeof(struct tcphdr));
+        t1 = (struct tcphdr *) skb_push(buff, tot_len);
 
         /* Swap the send and the receive. */
         memset(t1, 0, sizeof(*t1));
         t1->dest = th->source;
         t1->source = th->dest;
-        t1->doff = sizeof(*t1)/4;
+        t1->doff = tot_len / 4;
         t1->rst = 1;
   
         if(th->ack) {
@@ -607,6 +1029,22 @@ static void tcp_v6_send_reset(struct sk_buff *skb)
                                     + skb->len - (th->doff<<2));
         }
 
+#ifdef CONFIG_TCP_MD5SIG
+        if (key) {
+                u32 *opt = (u32*)(t1 + 1);
+                opt[0] = htonl((TCPOPT_NOP << 24) |
+                               (TCPOPT_NOP << 16) |
+                               (TCPOPT_MD5SIG << 8) |
+                               TCPOLEN_MD5SIG);
+                tcp_v6_do_calc_md5_hash((__u8*)&opt[1],
+                                        key,
+                                        &skb->nh.ipv6h->daddr,
+                                        &skb->nh.ipv6h->saddr,
+                                        t1, IPPROTO_TCP,
+                                        tot_len);
+        }
+#endif
+
         buff->csum = csum_partial((char *)t1, sizeof(*t1), 0);
 
         memset(&fl, 0, sizeof(fl));
@@ -637,15 +1075,37 @@ static void tcp_v6_send_reset(struct sk_buff *skb)
         kfree_skb(buff);
 }
 
-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 tcp_timewait_sock *tw,
+                            struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 ts)
 {
         struct tcphdr *th = skb->h.th, *t1;
         struct sk_buff *buff;
         struct flowi fl;
         int tot_len = sizeof(struct tcphdr);
+        u32 *topt;
+#ifdef CONFIG_TCP_MD5SIG
+        struct tcp_md5sig_key *key;
+        struct tcp_md5sig_key tw_key;
+#endif
+
+#ifdef CONFIG_TCP_MD5SIG
+        if (!tw && skb->sk) {
+                key = tcp_v6_md5_do_lookup(skb->sk, &skb->nh.ipv6h->daddr);
+        } else if (tw && tw->tw_md5_keylen) {
+                tw_key.key = tw->tw_md5_key;
+                tw_key.keylen = tw->tw_md5_keylen;
+                key = &tw_key;
+        } else {
+                key = NULL;
+        }
+#endif
 
         if (ts)
                 tot_len += TCPOLEN_TSTAMP_ALIGNED;
+#ifdef CONFIG_TCP_MD5SIG
+        if (key)
+                tot_len += TCPOLEN_MD5SIG_ALIGNED;
+#endif
 
         buff = alloc_skb(MAX_HEADER + sizeof(struct ipv6hdr) + tot_len,
                          GFP_ATOMIC);
@@ -665,15 +1125,29 @@ static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32
         t1->ack_seq = htonl(ack);
         t1->ack = 1;
         t1->window = htons(win);
+
+        topt = (u32*)(t1 + 1);
         
         if (ts) {
-                u32 *ptr = (u32*)(t1 + 1);
-                *ptr++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
-                               (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
-                *ptr++ = htonl(tcp_time_stamp);
-                *ptr = htonl(ts);
+                *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
+                                (TCPOPT_TIMESTAMP << 8) | TCPOLEN_TIMESTAMP);
+                *topt++ = htonl(tcp_time_stamp);
+                *topt = htonl(ts);
         }
 
+#ifdef CONFIG_TCP_MD5SIG
+        if (key) {
+                *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
+                                (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
+                tcp_v6_do_calc_md5_hash((__u8 *)topt,
+                                        key,
+                                        &skb->nh.ipv6h->daddr,
+                                        &skb->nh.ipv6h->saddr,
+                                        t1, IPPROTO_TCP,
+                                        tot_len);
+        }
+#endif
+
         buff->csum = csum_partial((char *)t1, tot_len, 0);
 
         memset(&fl, 0, sizeof(fl));
@@ -704,9 +1178,9 @@ static void tcp_v6_send_ack(struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32
 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 {
         struct inet_timewait_sock *tw = inet_twsk(sk);
-        const struct tcp_timewait_sock *tcptw = tcp_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(tcptw, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
                         tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
                         tcptw->tw_ts_recent);
 
@@ -715,7 +1189,7 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 
 static void tcp_v6_reqsk_send_ack(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(NULL, skb, tcp_rsk(req)->snt_isn + 1, tcp_rsk(req)->rcv_isn + 1, req->rcv_wnd, req->ts_recent);
 }
 
 
@@ -786,6 +1260,10 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
         if (req == NULL)
                 goto drop;
 
+#ifdef CONFIG_TCP_MD5SIG
+        tcp_rsk(req)->af_specific = &tcp_request_sock_ipv6_ops;
+#endif
+
         tcp_clear_options(&tmp_opt);
         tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr);
         tmp_opt.user_mss = tp->rx_opt.user_mss;
@@ -844,6 +1322,9 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
         struct tcp_sock *newtp;
         struct sock *newsk;
         struct ipv6_txoptions *opt;
+#ifdef CONFIG_TCP_MD5SIG
+        struct tcp_md5sig_key *key;
+#endif
 
         if (skb->protocol == htons(ETH_P_IP)) {
                 /*
@@ -874,6 +1355,10 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 
                 inet_csk(newsk)->icsk_af_ops = &ipv6_mapped;
                 newsk->sk_backlog_rcv = tcp_v4_do_rcv;
+#ifdef CONFIG_TCP_MD5SIG
+                newtp->af_specific = &tcp_sock_ipv6_mapped_specific;
+#endif
+
                 newnp->pktoptions  = NULL;
                 newnp->opt         = NULL;
                 newnp->mcast_oif   = inet6_iif(skb);
@@ -1008,6 +1493,23 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 
         newinet->daddr = newinet->saddr = newinet->rcv_saddr = LOOPBACK4_IPV6;
 
+#ifdef CONFIG_TCP_MD5SIG
+        /* Copy over the MD5 key from the original socket */
+        if ((key = tcp_v6_md5_do_lookup(sk, &newnp->daddr)) != NULL) {
+                /* We're using one, so create a matching key
+                 * on the newsk structure. If we fail to get
+                 * memory, then we end up not copying the key
+                 * across. Shucks.
+                 */
+                char *newkey = kmalloc(key->keylen, GFP_ATOMIC);
+                if (newkey) {
+                        memcpy(newkey, key->key, key->keylen);
+                        tcp_v6_md5_do_add(newsk, &inet6_sk(sk)->daddr,
+                                          newkey, key->keylen);
+                }
+        }
+#endif
+
         __inet6_hash(&tcp_hashinfo, newsk);
         inet_inherit_port(&tcp_hashinfo, sk, newsk);
 
@@ -1067,6 +1569,11 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
         if (skb->protocol == htons(ETH_P_IP))
                 return tcp_v4_do_rcv(sk, skb);
 
+#ifdef CONFIG_TCP_MD5SIG
+        if (tcp_v6_inbound_md5_hash (sk, skb))
+                goto discard;
+#endif
+
         if (sk_filter(sk, skb))
                 goto discard;
 
@@ -1132,7 +1639,7 @@ static int tcp_v6_do_rcv(struct sock *sk, struct sk_buff *skb)
         return 0;
 
 reset:
-        tcp_v6_send_reset(skb);
+        tcp_v6_send_reset(sk, skb);
 discard:
         if (opt_skb)
                 __kfree_skb(opt_skb);
@@ -1257,7 +1764,7 @@ no_tcp_socket:
 bad_packet:
                 TCP_INC_STATS_BH(TCP_MIB_INERRS);
         } else {
-                tcp_v6_send_reset(skb);
+                tcp_v6_send_reset(NULL, skb);
         }
 
 discard_it:
@@ -1336,6 +1843,15 @@ static struct inet_connection_sock_af_ops ipv6_specific = {
 #endif
 };
 
+static struct tcp_sock_af_ops tcp_sock_ipv6_specific = {
+#ifdef CONFIG_TCP_MD5SIG
+        .md5_lookup     =       tcp_v6_md5_lookup,
+        .calc_md5_hash  =       tcp_v6_calc_md5_hash,
+        .md5_add        =       tcp_v6_md5_add_func,
+        .md5_parse      =       tcp_v6_parse_md5_keys,
+#endif
+};
+
 /*
  *      TCP over IPv4 via INET6 API
  */
@@ -1358,6 +1874,15 @@ static struct inet_connection_sock_af_ops ipv6_mapped = {
 #endif
 };
 
+static struct tcp_sock_af_ops tcp_sock_ipv6_mapped_specific = {
+#ifdef CONFIG_TCP_MD5SIG
+        .md5_lookup     =       tcp_v4_md5_lookup,
+        .calc_md5_hash  =       tcp_v4_calc_md5_hash,
+        .md5_add        =       tcp_v6_md5_add_func,
+        .md5_parse      =       tcp_v6_parse_md5_keys,
+#endif
+};
+
 /* NOTE: A lot of things set to zero explicitly by call to
  *       sk_alloc() so need not be done here.
  */
@@ -1397,6 +1922,10 @@ static int tcp_v6_init_sock(struct sock *sk)
         sk->sk_write_space = sk_stream_write_space;
         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 
+#ifdef CONFIG_TCP_MD5SIG
+        tp->af_specific = &tcp_sock_ipv6_specific;
+#endif
+
         sk->sk_sndbuf = sysctl_tcp_wmem[1];
         sk->sk_rcvbuf = sysctl_tcp_rmem[1];
 
@@ -1407,6 +1936,11 @@ static int tcp_v6_init_sock(struct sock *sk)
 
 static int tcp_v6_destroy_sock(struct sock *sk)
 {
+#ifdef CONFIG_TCP_MD5SIG
+        /* Clean up the MD5 key list */
+        if (tcp_sk(sk)->md5sig_info)
+                tcp_v6_clear_md5_list(sk);
+#endif
         tcp_v4_destroy_sock(sk);
         return inet6_destroy_sock(sk);
 }