Commit 595da751 authored by Antony Antony's avatar Antony Antony Committed by Jakub Kicinski
Browse files

icmp: fix ICMP error source address when xfrm policy matches 



When an IPsec gateway generates an ICMP error (e.g., Destination Host
Unreachable), the source address incorrectly shows the unreachable
destination instead of the gateway's address. IPv6 behaves correctly.

Before fix:
  ping 10.1.6.3
  From 10.1.6.3 icmp_seq=1 Destination Host Unreachable
  (wrong - 10.1.6.3 is the unreachable host)

After fix:
  ping 10.1.6.3
  From 10.1.5.2 icmp_seq=1 Destination Host Unreachable
  (correct - 10.1.5.2 is the gateway)

The fix removes the memcpy that overwrote fl4 with fl4_dec after
xfrm_lookup(). A follow-up commit adds a selftest.

Fixes: 415b3334 ("icmp: Fix regression in nexthop resolution during replies.")
Cc: stable+noautosel@kernel.org # Avoid false positives in tests
Signed-off-by: default avatarAntony Antony <antony.antony@secunet.com>
Acked-by: default avatarTobias Brunner <tobias@strongswan.org>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/19a0156ff6e76baa323a81d710510d399a6ff63a.1772101380.git.antony.antony@secunet.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent d578b472

net/ipv4/icmp.c

+0 −1
Original line number Diff line number Diff line
@@ -591,7 +591,6 @@ static struct rtable *icmp_route_lookup(struct net *net, struct flowi4 *fl4, 
	rt2 = dst_rtable(dst2);

	if (!IS_ERR(dst2)) {

		dst_release(&rt->dst);

		memcpy(fl4, &fl4_dec, sizeof(*fl4));

		rt = rt2;

	} else if (PTR_ERR(dst2) == -EPERM) {

		if (rt)