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ila: block BH in ila_output()

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[ Upstream commit cf28ff8e4c ]

As explained in commit 1378817486 ("tipc: block BH
before using dst_cache"), net/core/dst_cache.c
helpers need to be called with BH disabled.

ila_output() is called from lwtunnel_output()
possibly from process context, and under rcu_read_lock().

We might be interrupted by a softirq, re-enter ila_output()
and corrupt dst_cache data structures.

Fix the race by using local_bh_disable().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Link: https://lore.kernel.org/r/20240531132636.2637995-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Eric Dumazet 2024-05-31 13:26:35 +00:00 committed by Greg Kroah-Hartman
parent 5f7ca37869
commit b4eb25a3d7
1 changed files with 6 additions and 1 deletions
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7
net/ipv6/ila/ila_lwt.c
View file

@ -58,7 +58,9 @@ static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
return orig_dst->lwtstate->orig_output(net, sk, skb);
}
local_bh_disable();
dst = dst_cache_get(&ilwt->dst_cache);
local_bh_enable();
if (unlikely(!dst)) {
struct ipv6hdr *ip6h = ipv6_hdr(skb);
struct flowi6 fl6;
@ -86,8 +88,11 @@ static int ila_output(struct net *net, struct sock *sk, struct sk_buff *skb)
goto drop;
}
if (ilwt->connected)
if (ilwt->connected) {
local_bh_disable();
dst_cache_set_ip6(&ilwt->dst_cache, dst, &fl6.saddr);
local_bh_enable();
}
}
skb_dst_set(skb, dst);