[PATCH 4.9 09/44] ipv4: recompile ip options in ipv4_link_failure

Greg Kroah-Hartman
2019-04-24T17:25:56Z

From: Stephen Suryaputra <ssuryaextr@gmail.com>

[ Upstream commit ed0de45a1008991fdaa27a0152befcb74d126a8b ]

Recompile IP options since IPCB may not be valid anymore when
ipv4_link_failure is called from arp_error_report.

Refer to the commit 3da1ed7ac398 ("net: avoid use IPCB in cipso_v4_error")
and the commit before that (9ef6b42ad6fd) for a similar issue.

Signed-off-by: Stephen Suryaputra <ssuryaextr@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/route.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1171,8 +1171,16 @@ static struct dst_entry *ipv4_dst_check(
static void ipv4_link_failure(struct sk_buff *skb)
{
struct rtable *rt;
+ struct ip_options opt;

- icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0);
+ /* Recompile ip options since IPCB may not be valid anymore.
+ */
+ memset(&opt, 0, sizeof(opt));
+ opt.optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
+ if (__ip_options_compile(dev_net(skb->dev), &opt, skb, NULL))
+ return;
+
+ __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_UNREACH, 0, &opt);

rt = skb_rtable(skb);
if (rt)