If we disabled IPv6 from the kernel command line (ipv6.disable=1), we should
not call ip6_err_gen_icmpv6_unreach(). This:
ip link add sit1 type sit local 192.0.2.1 remote 192.0.2.2 ttl 1
ip link set sit1 up
ip addr add 198.51.100.1/24 dev sit1
ping 198.51.100.2
if IPv6 is disabled at boot time, will crash the kernel.
v2: there's no need to use in6_dev_get(), use __in6_dev_get() instead,
as we only need to check that idev exists and we are under
rcu_read_lock() (from netif_receive_skb_internal()).
Reported-by: Jianlin Shi <ji...@redhat.com>
Fixes: ca15a078bd90 ("sit: generate icmpv6 error when receiving icmpv4 error")
Cc: Oussama Ghorbel <ghor...@pivasoftware.com>
Signed-off-by: Hangbin Liu <liuhang...@gmail.com>
Reviewed-by: Stefano Brivio <sbri...@redhat.com>
---
net/ipv6/sit.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 1e03305c0549..e8a1dabef803 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -546,7 +546,8 @@ static int ipip6_err(struct sk_buff *skb, u32 info)
}
err = 0;
- if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
+ if (__in6_dev_get(skb->dev) &&
+ !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
goto out;
if (t->parms.iph.daddr == 0)
--
2.19.2
