xfrm: Don't accidentally set RTO_ONLINK in decode_session4()

commit 23e7b1bfed61e301853b5e35472820d919498278 upstream.

Similar to commit 94e2238969e8 ("xfrm4: strip ECN bits from tos field"),
clear the ECN bits from iph->tos when setting ->flowi4_tos.
This ensures that the last bit of ->flowi4_tos is cleared, so
ip_route_output_key_hash() isn't going to restrict the scope of the
route lookup.

Use ~INET_ECN_MASK instead of IPTOS_RT_MASK, because we have no reason
to clear the high order bits.

Found by code inspection, compile tested only.

Fixes: 4da3089f2b58 ("[IPSEC]: Use TOS when doing tunnel lookups")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index bef7d0d..37b149f 100644 (file)
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -31,6 +31,7 @@
 #include <linux/if_tunnel.h>
 #include <net/dst.h>
 #include <net/flow.h>
+#include <net/inet_ecn.h>
 #include <net/xfrm.h>
 #include <net/ip.h>
 #include <net/gre.h>
@@ -3297,7 +3298,7 @@ decode_session4(struct sk_buff *skb, struct flowi *fl, bool reverse)
        fl4->flowi4_proto = iph->protocol;
        fl4->daddr = reverse ? iph->saddr : iph->daddr;
        fl4->saddr = reverse ? iph->daddr : iph->saddr;
-       fl4->flowi4_tos = iph->tos;
+       fl4->flowi4_tos = iph->tos & ~INET_ECN_MASK;
 
        if (!ip_is_fragment(iph)) {
                switch (iph->protocol) {