David S. Miller wrote:
From: Patrick McHardy <[EMAIL PROTECTED]>
Date: Thu, 08 Sep 2005 23:00:39 +0200


When an error is returned in some cases xfrm_lookup releases
the dst_entry and sets the pointer to NULL, in some it doesn't.
There are multiple dst leaks in users of xfrm_lookup because
not all take care to release the dst_entry when an error was
returned. Is there a reason why xfrm_lookup doesn't always
release the dst_entry?


It's a known bug and even listed on the netdev TODO list
at:

        http://vger.kernel.org/~davem/net_todo.html

:-)

In that case, here is a patch to always release the dst entry
on error and set the pointer to NULL. It also removes now
unnecessary dst_release calls in users of xfrm_lookup.

[XFRM]: Always release dst_entry on error in xfrm_lookup

Signed-off-by: Patrick McHardy <[EMAIL PROTECTED]>

---
commit 87c9b944bfcd3a536bc85760974a2eff5336ed28
tree dea19208ef2a38ba78cbe65684ddef07e7ead24b
parent 975f5749e0962c59b9b8f93abee8adf3e2bc292d
author Patrick McHardy <[EMAIL PROTECTED]> Thu, 08 Sep 2005 23:43:34 +0200
committer Patrick McHardy <[EMAIL PROTECTED]> Thu, 08 Sep 2005 23:43:34 +0200

 net/ipv4/netfilter/ipt_REJECT.c  |    5 +----
 net/ipv6/datagram.c              |    4 +---
 net/ipv6/icmp.c                  |    5 ++---
 net/ipv6/ndisc.c                 |   16 ++++------------
 net/ipv6/netfilter/ip6t_REJECT.c |    5 +----
 net/ipv6/raw.c                   |    4 +---
 net/ipv6/tcp_ipv6.c              |   15 +++------------
 net/ipv6/udp.c                   |    4 +---
 net/xfrm/xfrm_policy.c           |    8 ++++----
 9 files changed, 18 insertions(+), 48 deletions(-)

diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c
--- a/net/ipv4/netfilter/ipt_REJECT.c
+++ b/net/ipv4/netfilter/ipt_REJECT.c
@@ -92,10 +92,7 @@ static inline struct rtable *route_rever
        fl.fl_ip_sport = tcph->dest;
        fl.fl_ip_dport = tcph->source;
 
-       if (xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0)) {
-               dst_release(&rt->u.dst);
-               rt = NULL;
-       }
+       xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0);
 
        return rt;
 }
diff --git a/net/ipv6/datagram.c b/net/ipv6/datagram.c
--- a/net/ipv6/datagram.c
+++ b/net/ipv6/datagram.c
@@ -175,10 +175,8 @@ ipv4_connected:
        if (final_p)
                ipv6_addr_copy(&fl.fl6_dst, final_p);
 
-       if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0) {
-               dst_release(dst);
+       if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
                goto out;
-       }
 
        /* source address lookup done in ip6_dst_lookup */
 
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -374,7 +374,7 @@ void icmpv6_send(struct sk_buff *skb, in
        if (err)
                goto out;
        if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
-               goto out_dst_release;
+               goto out;
 
        if (ipv6_addr_is_multicast(&fl.fl6_dst))
                hlimit = np->mcast_hops;
@@ -464,7 +464,7 @@ static void icmpv6_echo_reply(struct sk_
        if (err)
                goto out;
        if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
-               goto out_dst_release;
+               goto out;
 
        if (ipv6_addr_is_multicast(&fl.fl6_dst))
                hlimit = np->mcast_hops;
@@ -496,7 +496,6 @@ static void icmpv6_echo_reply(struct sk_
 out_put: 
        if (likely(idev != NULL))
                in6_dev_put(idev);
-out_dst_release:
        dst_release(dst);
 out: 
        icmpv6_xmit_unlock();
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -447,10 +447,8 @@ static void ndisc_send_na(struct net_dev
                return;
 
        err = xfrm_lookup(&dst, &fl, NULL, 0);
-       if (err < 0) {
-               dst_release(dst);
+       if (err < 0)
                return;
-       }
 
        if (inc_opt) {
                if (dev->addr_len)
@@ -539,10 +537,8 @@ void ndisc_send_ns(struct net_device *de
                return;
 
        err = xfrm_lookup(&dst, &fl, NULL, 0);
-       if (err < 0) {
-               dst_release(dst);
+       if (err < 0)
                return;
-       }
 
        len = sizeof(struct icmp6hdr) + sizeof(struct in6_addr);
        send_llinfo = dev->addr_len && !ipv6_addr_any(saddr);
@@ -616,10 +612,8 @@ void ndisc_send_rs(struct net_device *de
                return;
 
        err = xfrm_lookup(&dst, &fl, NULL, 0);
-       if (err < 0) {
-               dst_release(dst);
+       if (err < 0)
                return;
-       }
 
        len = sizeof(struct icmp6hdr);
        if (dev->addr_len)
@@ -1353,10 +1347,8 @@ void ndisc_send_redirect(struct sk_buff 
                return;
 
        err = xfrm_lookup(&dst, &fl, NULL, 0);
-       if (err) {
-               dst_release(dst);
+       if (err)
                return;
-       }
 
        rt = (struct rt6_info *) dst;
 
diff --git a/net/ipv6/netfilter/ip6t_REJECT.c b/net/ipv6/netfilter/ip6t_REJECT.c
--- a/net/ipv6/netfilter/ip6t_REJECT.c
+++ b/net/ipv6/netfilter/ip6t_REJECT.c
@@ -100,11 +100,8 @@ static void send_reset(struct sk_buff *o
        dst = ip6_route_output(NULL, &fl);
        if (dst == NULL)
                return;
-       if (dst->error ||
-           xfrm_lookup(&dst, &fl, NULL, 0)) {
-               dst_release(dst);
+       if (dst->error || xfrm_lookup(&dst, &fl, NULL, 0))
                return;
-       }
 
        hh_len = (dst->dev->hard_header_len + 15)&~15;
        nskb = alloc_skb(hh_len + 15 + dst->header_len + sizeof(struct ipv6hdr)
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -782,10 +782,8 @@ static int rawv6_sendmsg(struct kiocb *i
        if (final_p)
                ipv6_addr_copy(&fl.fl6_dst, final_p);
 
-       if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0) {
-               dst_release(dst);
+       if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
                goto out;
-       }
 
        if (hlimit < 0) {
                if (ipv6_addr_is_multicast(&fl.fl6_dst))
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -632,10 +632,8 @@ static int tcp_v6_connect(struct sock *s
        if (final_p)
                ipv6_addr_copy(&fl.fl6_dst, final_p);
 
-       if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0) {
-               dst_release(dst);
+       if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0)
                goto failure;
-       }
 
        if (saddr == NULL) {
                saddr = &fl.fl6_src;
@@ -888,7 +886,6 @@ static int tcp_v6_send_synack(struct soc
        }
 
 done:
-       dst_release(dst);
         if (opt && opt != np->opt)
                sock_kfree_s(sk, opt, opt->tot_len);
        return err;
@@ -1001,10 +998,8 @@ static void tcp_v6_send_reset(struct sk_
        /* sk = NULL, but it is safe for now. RST socket required. */
        if (!ip6_dst_lookup(NULL, &buff->dst, &fl)) {
 
-               if ((xfrm_lookup(&buff->dst, &fl, NULL, 0)) < 0) {
-                       dst_release(buff->dst);
+               if ((xfrm_lookup(&buff->dst, &fl, NULL, 0)) < 0)
                        return;
-               }
 
                ip6_xmit(NULL, buff, &fl, NULL, 0);
                TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
@@ -1068,10 +1063,8 @@ static void tcp_v6_send_ack(struct sk_bu
        fl.fl_ip_sport = t1->source;
 
        if (!ip6_dst_lookup(NULL, &buff->dst, &fl)) {
-               if ((xfrm_lookup(&buff->dst, &fl, NULL, 0)) < 0) {
-                       dst_release(buff->dst);
+               if ((xfrm_lookup(&buff->dst, &fl, NULL, 0)) < 0)
                        return;
-               }
                ip6_xmit(NULL, buff, &fl, NULL, 0);
                TCP_INC_STATS_BH(TCP_MIB_OUTSEGS);
                return;
@@ -1734,7 +1727,6 @@ static int tcp_v6_rebuild_header(struct 
 
                if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0) {
                        sk->sk_err_soft = -err;
-                       dst_release(dst);
                        return err;
                }
 
@@ -1787,7 +1779,6 @@ static int tcp_v6_xmit(struct sk_buff *s
 
                if ((err = xfrm_lookup(&dst, &fl, sk, 0)) < 0) {
                        sk->sk_route_caps = 0;
-                       dst_release(dst);
                        return err;
                }
 
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -799,10 +799,8 @@ do_udp_sendmsg:
        if (final_p)
                ipv6_addr_copy(&fl->fl6_dst, final_p);
 
-       if ((err = xfrm_lookup(&dst, fl, sk, 0)) < 0) {
-               dst_release(dst);
+       if ((err = xfrm_lookup(&dst, fl, sk, 0)) < 0)
                goto out;
-       }
 
        if (hlimit < 0) {
                if (ipv6_addr_is_multicast(&fl->fl6_dst))
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -765,8 +765,8 @@ restart:
        switch (policy->action) {
        case XFRM_POLICY_BLOCK:
                /* Prohibit the flow */
-               xfrm_pol_put(policy);
-               return -EPERM;
+               err = -EPERM;
+               goto error;
 
        case XFRM_POLICY_ALLOW:
                if (policy->xfrm_nr == 0) {
@@ -782,8 +782,8 @@ restart:
                 */
                dst = xfrm_find_bundle(fl, policy, family);
                if (IS_ERR(dst)) {
-                       xfrm_pol_put(policy);
-                       return PTR_ERR(dst);
+                       err = PTR_ERR(dst);
+                       goto error;
                }
 
                if (dst)

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