[PATCH 3.2 088/140] xfrm: Return error on unknown encap_type in init_state

[Ben Hutchings]

3.2.100-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>

commit bcfd09f7837f5240c30fd2f52ee7293516641faa upstream.

Currently esp will happily create an xfrm state with an unknown
encap type for IPv4, without setting the necessary state parameters.
This patch fixes it by returning -EINVAL.

There is a similar problem in IPv6 where if the mode is unknown
we will skip initialisation while returning zero.  However, this
is harmless as the mode has already been checked further up the
stack.  This patch removes this anomaly by aligning the IPv6
behaviour with IPv4 and treating unknown modes (which cannot
actually happen) as transport mode.

Fixes: 38320c70d282 ("[IPSEC]: Use crypto_aead and authenc in ESP")
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Steffen Klassert <steffen.klassert@xxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 net/ipv4/esp4.c | 1 +
 net/ipv6/esp6.c | 3 +--
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -658,6 +658,7 @@ static int esp_init_state(struct xfrm_st
 
 		switch (encap->encap_type) {
 		default:
+			err = -EINVAL;
 			goto error;
 		case UDP_ENCAP_ESPINUDP:
 			x->props.header_len += sizeof(struct udphdr);
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -606,13 +606,12 @@ static int esp6_init_state(struct xfrm_s
 			x->props.header_len += IPV4_BEET_PHMAXLEN +
 				               (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
 		break;
+	default:
 	case XFRM_MODE_TRANSPORT:
 		break;
 	case XFRM_MODE_TUNNEL:
 		x->props.header_len += sizeof(struct ipv6hdr);
 		break;
-	default:
-		goto error;
 	}
 
 	align = ALIGN(crypto_aead_blocksize(aead), 4);