[PATCH] xfrm: Use xfrm_state selector for BEET input

From: Herbert Xu <herbert@gondor.apana.org.au>
To: Steffen Klassert <steffen.klassert@secunet.com>
Cc: netdev@vger.kernel.org, David George <David.George@sophos.com>,
	Markus Trapp <markus.trapp@secunet.com>
Subject: [PATCH] xfrm: Use xfrm_state selector for BEET input
Date: Wed, 7 Jun 2023 16:38:47 +0800	[thread overview]
Message-ID: <ZIBCFyszqwJlZd/V@gondor.apana.org.au> (raw)
In-Reply-To: <ZH8OSd1ElPIKCFa+@gauss3.secunet.de>

On Tue, Jun 06, 2023 at 12:45:29PM +0200, Steffen Klassert wrote:
>
> the assumption that the L4 protocol on BEET mode can be
> just IPIP or BEETPH seems not to be correct. One of
> our testcaces hit the second WARN_ON_ONCE() in
> xfrm_prepare_input. In that case the L4 protocol
> is UDP. Looks like we need some other way to
> dertermine the inner protocol family.

Oops, that was a thinko on my part:

---8<---
For BEET the inner address and therefore family is stored in the
xfrm_state selector.  Use that when decapsulating an input packet
instead of incorrectly relying on a non-existent tunnel protocol.

Fixes: 5f24f41e8ea6 ("xfrm: Remove inner/outer modes from input path")
Reported-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 39fb91ff23d9..bdaed1d1ff97 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -330,11 +330,10 @@ xfrm_inner_mode_encap_remove(struct xfrm_state *x,
 {
 	switch (x->props.mode) {
 	case XFRM_MODE_BEET:
-		switch (XFRM_MODE_SKB_CB(skb)->protocol) {
-		case IPPROTO_IPIP:
-		case IPPROTO_BEETPH:
+		switch (x->sel.family) {
+		case AF_INET:
 			return xfrm4_remove_beet_encap(x, skb);
-		case IPPROTO_IPV6:
+		case AF_INET6:
 			return xfrm6_remove_beet_encap(x, skb);
 		}
 		break;
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
