netdev - [PATCH 4/7] net: Fix devinet_sysctl

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]

Message-ID: <m1k54kqtiu.fsf@fess.ebiederm.org>
Date:	Wed, 13 May 2009 19:59:21 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	David Miller <davem@...emloft.net>
Cc:	<netdev@...r.kernel.org>, Herbert Xu <herbert@...dor.apana.org.au>,
	Stephen Hemminger <shemminger@...tta.com>,
	Ben Greear <greearb@...delatech.com>,
	Patrick McHardy <kaber@...sh.net>
Subject: [PATCH 4/7] net: Fix devinet_sysctl_forward


sysctls are unregistered with the rntl_lock held making
it unsafe to unconditionally grab the the rtnl_lock.  Instead
we need to call rtnl_trylock and restart the system call
if we can not grab it.  Otherwise we could deadlock at unregistration
time.

Signed-off-by: Eric W. Biederman <ebiederm@...stanetworks.com>
---
 net/ipv4/devinet.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 126bb91..3863c3a 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1347,7 +1347,8 @@ static int devinet_sysctl_forward(ctl_table *ctl, int write,
 		struct net *net = ctl->extra2;
 
 		if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
-			rtnl_lock();
+			if (!rtnl_trylock())
+				return restart_syscall();
 			if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) {
 				inet_forward_change(net);
 			} else if (*valp) {
-- 
1.6.0.6

--
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