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-prev] [thread-next>] [day] [month] [year] [list]
Date:   Mon, 21 Jan 2019 14:44:10 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, JianJhen Chen <kchen@...ology.com>,
        JinLin Chen <jlchen@...ology.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.9 14/51] net: bridge: fix a bug on using a neighbour cache entry without checking its state

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: JianJhen Chen <kchen@...ology.com>

[ Upstream commit 4c84edc11b76590859b1e45dd676074c59602dc4 ]

When handling DNAT'ed packets on a bridge device, the neighbour cache entry
from lookup was used without checking its state. It means that a cache entry
in the NUD_STALE state will be used directly instead of entering the NUD_DELAY
state to confirm the reachability of the neighbor.

This problem becomes worse after commit 2724680bceee ("neigh: Keep neighbour
cache entries if number of them is small enough."), since all neighbour cache
entries in the NUD_STALE state will be kept in the neighbour table as long as
the number of cache entries does not exceed the value specified in gc_thresh1.

This commit validates the state of a neighbour cache entry before using
the entry.

Signed-off-by: JianJhen Chen <kchen@...ology.com>
Reviewed-by: JinLin Chen <jlchen@...ology.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/bridge/br_netfilter_hooks.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/bridge/br_netfilter_hooks.c
+++ b/net/bridge/br_netfilter_hooks.c
@@ -275,7 +275,7 @@ int br_nf_pre_routing_finish_bridge(stru
 		struct nf_bridge_info *nf_bridge = nf_bridge_info_get(skb);
 		int ret;
 
-		if (neigh->hh.hh_len) {
+		if ((neigh->nud_state & NUD_CONNECTED) && neigh->hh.hh_len) {
 			neigh_hh_bridge(&neigh->hh, skb);
 			skb->dev = nf_bridge->physindev;
 			ret = br_handle_frame_finish(net, sk, skb);


Powered by blists - more mailing lists