4.19-stable review patch. If anyone has any objections, please let me know.
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From: Kyle Zeng zengyhkyle@gmail.com
[ Upstream commit 0113d9c9d1ccc07f5a3710dac4aa24b6d711278c ]
Currently, we assume the skb is associated with a device before calling __ip_options_compile, which is not always the case if it is re-routed by ipvs. When skb->dev is NULL, dev_net(skb->dev) will become null-dereference. This patch adds a check for the edge case and switch to use the net_device from the rtable when skb->dev is NULL.
Fixes: ed0de45a1008 ("ipv4: recompile ip options in ipv4_link_failure") Suggested-by: David Ahern dsahern@kernel.org Signed-off-by: Kyle Zeng zengyhkyle@gmail.com Cc: Stephen Suryaputra ssuryaextr@gmail.com Cc: Vadim Fedorenko vfedorenko@novek.ru Reviewed-by: David Ahern dsahern@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/route.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 57e2316529d00..9753d07bfc0bf 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1215,6 +1215,7 @@ static struct dst_entry *ipv4_dst_check(struct dst_entry *dst, u32 cookie)
static void ipv4_send_dest_unreach(struct sk_buff *skb) { + struct net_device *dev; struct ip_options opt; int res;
@@ -1232,7 +1233,8 @@ static void ipv4_send_dest_unreach(struct sk_buff *skb) opt.optlen = ip_hdr(skb)->ihl * 4 - sizeof(struct iphdr);
rcu_read_lock(); - res = __ip_options_compile(dev_net(skb->dev), &opt, skb, NULL); + dev = skb->dev ? skb->dev : skb_rtable(skb)->dst.dev; + res = __ip_options_compile(dev_net(dev), &opt, skb, NULL); rcu_read_unlock();
if (res)