[SRU][J:linux-bluefield][PATCH v1 7/9] xfrm: Silence warnings triggerable by bad packets

[Tony Duan]

From: Herbert Xu <herbert at gondor.apana.org.au>

BugLink: https://bugs.launchpad.net/bugs/2044427

After the elimination of inner modes, a couple of warnings that
were previously unreachable can now be triggered by malformed
inbound packets.

Fix this by:

1. Moving the setting of skb->protocol into the decap functions.
2. Returning -EINVAL when unexpected protocol is seen.

Reported-by: Maciej Żenczykowski<maze at google.com>
Fixes: 5f24f41e8ea6 ("xfrm: Remove inner/outer modes from input path")
Signed-off-by: Herbert Xu <herbert at gondor.apana.org.au>
Reviewed-by: Maciej Żenczykowski <maze at google.com>
Signed-off-by: Steffen Klassert <steffen.klassert at secunet.com>
(cherry picked from commit 57010b8ece2821a1fdfdba2197d14a022f3769db)
Signed-off-by: Tony Duan <yifeid at nvidia.com>
---
 net/xfrm/xfrm_input.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 33c15fb2..eda890d 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -179,6 +179,8 @@ static int xfrm4_remove_beet_encap(struct xfrm_state *x, struct sk_buff *skb)
 	int optlen = 0;
 	int err = -EINVAL;
 
+	skb->protocol = htons(ETH_P_IP);
+
 	if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
 		struct ip_beet_phdr *ph;
 		int phlen;
@@ -231,6 +233,8 @@ static int xfrm4_remove_tunnel_encap(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err = -EINVAL;
 
+	skb->protocol = htons(ETH_P_IP);
+
 	if (!pskb_may_pull(skb, sizeof(struct iphdr)))
 		goto out;
 
@@ -266,6 +270,8 @@ static int xfrm6_remove_tunnel_encap(struct xfrm_state *x, struct sk_buff *skb)
 {
 	int err = -EINVAL;
 
+	skb->protocol = htons(ETH_P_IPV6);
+
 	if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 		goto out;
 
@@ -295,6 +301,8 @@ static int xfrm6_remove_beet_encap(struct xfrm_state *x, struct sk_buff *skb)
 	int size = sizeof(struct ipv6hdr);
 	int err;
 
+	skb->protocol = htons(ETH_P_IPV6);
+
 	err = skb_cow_head(skb, size + skb->mac_len);
 	if (err)
 		goto out;
@@ -346,6 +354,7 @@ static int xfrm6_remove_beet_encap(struct xfrm_state *x, struct sk_buff *skb)
 			return xfrm6_remove_tunnel_encap(x, skb);
 		break;
 		}
+		return -EINVAL;
 	}
 
 	WARN_ON_ONCE(1);
@@ -366,19 +375,6 @@ static int xfrm_prepare_input(struct xfrm_state *x, struct sk_buff *skb)
 		return -EAFNOSUPPORT;
 	}
 
-	switch (XFRM_MODE_SKB_CB(skb)->protocol) {
-	case IPPROTO_IPIP:
-	case IPPROTO_BEETPH:
-		skb->protocol = htons(ETH_P_IP);
-		break;
-	case IPPROTO_IPV6:
-		skb->protocol = htons(ETH_P_IPV6);
-		break;
-	default:
-		WARN_ON_ONCE(1);
-		break;
-	}
-
 	return xfrm_inner_mode_encap_remove(x, skb);
 }
 
-- 
1.8.3.1