netdev - [PATCH 1/2] ipv4: Invalidate the socket cached route on pmtu events if possible

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20130121115911.GE30530@secunet.com>
Date:	Mon, 21 Jan 2013 12:59:11 +0100
From:	Steffen Klassert <steffen.klassert@...unet.com>
To:	David Miller <davem@...emloft.net>
Cc:	"Yurij M. Plotnikov" <Yurij.Plotnikov@...etlabs.ru>,
	Julian Anastasov <ja@....bg>, netdev@...r.kernel.org
Subject: [PATCH 1/2] ipv4: Invalidate the socket cached route on pmtu events
 if possible

The route lookup in ipv4_sk_update_pmtu() might return a route
different from the route we cached at the socket. This is because
standart routes are per cpu, so each cpu has it's own struct rtable.
This means that we do not invalidate the socket cached route if the
NET_RX_SOFTIRQ is not served by the same cpu that the sending socket
uses. As a result, the cached route reused until we disconnect.

With this patch we invalidate the socket cached route if possible.
If the socket is owened by the user, we can't update the cached
route directly. A followup patch will implement socket release
callback functions for datagram sockets to handle this case.

Reported-by: Yurij M. Plotnikov <Yurij.Plotnikov@...etlabs.ru>
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/ipv4/route.c |   42 +++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 259cbee..132737a 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -965,7 +965,7 @@ void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu,
 }
 EXPORT_SYMBOL_GPL(ipv4_update_pmtu);
 
-void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
+static void __ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
 {
 	const struct iphdr *iph = (const struct iphdr *) skb->data;
 	struct flowi4 fl4;
@@ -978,6 +978,46 @@ void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
 		ip_rt_put(rt);
 	}
 }
+
+void ipv4_sk_update_pmtu(struct sk_buff *skb, struct sock *sk, u32 mtu)
+{
+	const struct iphdr *iph = (const struct iphdr *) skb->data;
+	struct flowi4 fl4;
+	struct rtable *rt;
+	struct dst_entry *dst;
+
+	bh_lock_sock(sk);
+	rt = (struct rtable *) __sk_dst_get(sk);
+
+	if (sock_owned_by_user(sk) || !rt) {
+		__ipv4_sk_update_pmtu(skb, sk, mtu);
+		goto out;
+	}
+
+	__build_flow_key(&fl4, sk, iph, 0, 0, 0, 0, 0);
+
+	if (!__sk_dst_check(sk, 0)) {
+		rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
+		if (IS_ERR(rt))
+			goto out;
+	}
+
+	__ip_rt_update_pmtu((struct rtable *) rt->dst.path, &fl4, mtu);
+
+	dst = dst_check(&rt->dst, 0);
+	if (!dst) {
+		rt = ip_route_output_flow(sock_net(sk), &fl4, sk);
+		if (IS_ERR(rt))
+			goto out;
+
+		dst = &rt->dst;
+	}
+
+	 __sk_dst_set(sk, dst);
+
+out:
+	bh_unlock_sock(sk);
+}
 EXPORT_SYMBOL_GPL(ipv4_sk_update_pmtu);
 
 void ipv4_redirect(struct sk_buff *skb, struct net *net,
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html