Subject: fix ip6_frag ctl
From: Daniel Lezcano <[EMAIL PROTECTED]>
Alexey Dobriyan reported an oops when unsharing the network
indefinitely inside a loop. This is because the ip6_frag is not per
namespace while the ctls are.
That happens at the fragment timer expiration: inet_frag_secret_rebuild
function is called and this one restarts the timer using the value stored
inside the sysctl field.
"mod_timer(&f->secret_timer, now + f->ctl->secret_interval);"
When the network is unshared, ip6_frag.ctl is initialized with the new
sysctl instances, but ip6_frag has only one instance. A race in this case
will appear because f->ctl can be modified during the read access in the
timer callback.
Until the ip6_frag is not per namespace, I discard the assignation to the
ctl field of ip6_frags in ip6_frag_sysctl_init when the network namespace
is not the init net.
Signed-off-by: Daniel Lezcano <[EMAIL PROTECTED]>
---
net/ipv6/reassembly.c | 3 +++
1 file changed, 3 insertions(+)
Index: net-2.6.25-misc/net/ipv6/reassembly.c
===================================================================
--- net-2.6.25-misc.orig/net/ipv6/reassembly.c
+++ net-2.6.25-misc/net/ipv6/reassembly.c
@@ -627,6 +627,9 @@ static struct inet6_protocol frag_protoc
void ipv6_frag_sysctl_init(struct net *net)
{
+ if (net != &init_net)
+ return;
+
ip6_frags.ctl = &net->ipv6.sysctl.frags;
}
