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authorEric Dumazet <edumazet@google.com>2024-05-31 16:26:33 +0300
committerJakub Kicinski <kuba@kernel.org>2024-06-04 04:50:08 +0300
commitdb0090c6eb12c31246438b7fe2a8f1b833e7a653 (patch)
treed7ac778dd6ff370c7b38190bfc2badc6a929bce1 /net/ipv6
parent2fe40483ec257de2a0d819ef88e3e76c7e261319 (diff)
downloadlinux-db0090c6eb12c31246438b7fe2a8f1b833e7a653.tar.xz
net: ipv6: rpl_iptunnel: block BH in rpl_output() and rpl_input()
As explained in commit 1378817486d6 ("tipc: block BH before using dst_cache"), net/core/dst_cache.c helpers need to be called with BH disabled. Disabling preemption in rpl_output() is not good enough, because rpl_output() is called from process context, lwtunnel_output() only uses rcu_read_lock(). We might be interrupted by a softirq, re-enter rpl_output() and corrupt dst_cache data structures. Fix the race by using local_bh_disable() instead of preempt_disable(). Apply a similar change in rpl_input(). Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexander Aring <aahringo@redhat.com> Acked-by: Paolo Abeni <pabeni@redhat.com> Link: https://lore.kernel.org/r/20240531132636.2637995-3-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/rpl_iptunnel.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/net/ipv6/rpl_iptunnel.c b/net/ipv6/rpl_iptunnel.c
index a013b92cbb86..2c83b7586422 100644
--- a/net/ipv6/rpl_iptunnel.c
+++ b/net/ipv6/rpl_iptunnel.c
@@ -212,9 +212,9 @@ static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *skb)
if (unlikely(err))
goto drop;
- preempt_disable();
+ local_bh_disable();
dst = dst_cache_get(&rlwt->cache);
- preempt_enable();
+ local_bh_enable();
if (unlikely(!dst)) {
struct ipv6hdr *hdr = ipv6_hdr(skb);
@@ -234,9 +234,9 @@ static int rpl_output(struct net *net, struct sock *sk, struct sk_buff *skb)
goto drop;
}
- preempt_disable();
+ local_bh_disable();
dst_cache_set_ip6(&rlwt->cache, dst, &fl6.saddr);
- preempt_enable();
+ local_bh_enable();
}
skb_dst_drop(skb);
@@ -268,23 +268,21 @@ static int rpl_input(struct sk_buff *skb)
return err;
}
- preempt_disable();
+ local_bh_disable();
dst = dst_cache_get(&rlwt->cache);
- preempt_enable();
if (!dst) {
ip6_route_input(skb);
dst = skb_dst(skb);
if (!dst->error) {
- preempt_disable();
dst_cache_set_ip6(&rlwt->cache, dst,
&ipv6_hdr(skb)->saddr);
- preempt_enable();
}
} else {
skb_dst_drop(skb);
skb_dst_set(skb, dst);
}
+ local_bh_enable();
err = skb_cow_head(skb, LL_RESERVED_SPACE(dst->dev));
if (unlikely(err))