3.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicolas Cavallari <nicolas.cavallari@xxxxxxxxxxxxxxxxxxxxxxx> [ Upstream commit fa19c2b050ab5254326f5fc07096dd3c6a8d5d58 ] If we cache them, the kernel will reuse them, independently of whether forwarding is enabled or not. Which means that if forwarding is disabled on the input interface where the first routing request comes from, then that unreachable result will be cached and reused for other interfaces, even if forwarding is enabled on them. The opposite is also true. This can be verified with two interfaces A and B and an output interface C, where B has forwarding enabled, but not A and trying ip route get $dst iif A from $src && ip route get $dst iif B from $src Signed-off-by: Nicolas Cavallari <nicolas.cavallari@xxxxxxxxxxxxxxxxxxxxxxx> Reviewed-by: Julian Anastasov <ja@xxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/route.c | 1 + 1 file changed, 1 insertion(+) --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1798,6 +1798,7 @@ local_input: no_route: RT_CACHE_STAT_INC(in_no_route); res.type = RTN_UNREACHABLE; + res.fi = NULL; goto local_input; /* -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html