Commit 7d460db9 authored by Daniel Lezcano's avatar Daniel Lezcano Committed by David S. Miller

[IPV6]: Fix ip6_frag ctl

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: default avatarDaniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ee63d22b
...@@ -627,6 +627,9 @@ static struct inet6_protocol frag_protocol = ...@@ -627,6 +627,9 @@ static struct inet6_protocol frag_protocol =
void ipv6_frag_sysctl_init(struct net *net) void ipv6_frag_sysctl_init(struct net *net)
{ {
if (net != &init_net)
return;
ip6_frags.ctl = &net->ipv6.sysctl.frags; ip6_frags.ctl = &net->ipv6.sysctl.frags;
} }
......
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