diff mbox series

xfrm: Silence warnings triggerable by bad packets

Message ID ZKNtndEkrzhtmqkF@gondor.apana.org.au (mailing list archive)
State Awaiting Upstream
Delegated to: Netdev Maintainers
Headers show
Series xfrm: Silence warnings triggerable by bad packets | expand

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Context Check Description
netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 13 this patch: 13
netdev/cc_maintainers warning 4 maintainers not CCed: kuba@kernel.org edumazet@google.com davem@davemloft.net pabeni@redhat.com
netdev/build_clang fail Errors and warnings before: 61 this patch: 20
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 13 this patch: 13
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 58 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Herbert Xu July 4, 2023, 12:53 a.m. UTC 
On Fri, Jun 30, 2023 at 08:37:58AM -0700, Maciej Żenczykowski wrote:
> Steffan, this isn't of course a patch meant for inclusion, instead just a WARN_ON hit report.
> The patch is simply what prints the following extra info:
> 
> xfrm_prepare_input: XFRM_MODE_SKB_CB(skb)->protocol: 17
> xfrm_inner_mode_encap_remove: x->props.mode: 1 XFRM_MODE_SKB_SB(skb)->protocol:17
> 
> (note: XFRM_MODE_TUNNEL=1 IPPROTO_UDP=17)

Thanks for the report.  This patch should fix the warnings:

---8<---
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@google.com>
Fixes: 5f24f41e8ea6 ("xfrm: Remove inner/outer modes from input path")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Comments

Maciej Żenczykowski July 5, 2023, 8:57 a.m. UTC | #1 
On Tue, Jul 4, 2023 at 2:54 AM Herbert Xu <herbert@gondor.apana.org.au> wrote:
>
> On Fri, Jun 30, 2023 at 08:37:58AM -0700, Maciej Żenczykowski wrote:
> > Steffan, this isn't of course a patch meant for inclusion, instead just a WARN_ON hit report.
> > The patch is simply what prints the following extra info:
> >
> > xfrm_prepare_input: XFRM_MODE_SKB_CB(skb)->protocol: 17
> > xfrm_inner_mode_encap_remove: x->props.mode: 1 XFRM_MODE_SKB_SB(skb)->protocol:17
> >
> > (note: XFRM_MODE_TUNNEL=1 IPPROTO_UDP=17)
>
> Thanks for the report.  This patch should fix the warnings:
>
> ---8<---
> 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@google.com>
> Fixes: 5f24f41e8ea6 ("xfrm: Remove inner/outer modes from input path")
> 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 815b38080401..d5ee96789d4b 100644
> --- a/net/xfrm/xfrm_input.c
> +++ b/net/xfrm/xfrm_input.c
> @@ -180,6 +180,8 @@ 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;
> @@ -232,6 +234,8 @@ 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;
>
> @@ -267,6 +271,8 @@ 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;
>
> @@ -296,6 +302,8 @@ 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 @@ xfrm_inner_mode_encap_remove(struct xfrm_state *x,
>                         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);
>  }

Reviewed-by: Maciej Żenczykowski <maze@google.com>
Steffen Klassert July 11, 2023, 9:04 a.m. UTC | #2 
On Tue, Jul 04, 2023 at 08:53:49AM +0800, Herbert Xu wrote:
> On Fri, Jun 30, 2023 at 08:37:58AM -0700, Maciej Żenczykowski wrote:
> > Steffan, this isn't of course a patch meant for inclusion, instead just a WARN_ON hit report.
> > The patch is simply what prints the following extra info:
> > 
> > xfrm_prepare_input: XFRM_MODE_SKB_CB(skb)->protocol: 17
> > xfrm_inner_mode_encap_remove: x->props.mode: 1 XFRM_MODE_SKB_SB(skb)->protocol:17
> > 
> > (note: XFRM_MODE_TUNNEL=1 IPPROTO_UDP=17)
> 
> Thanks for the report.  This patch should fix the warnings:
> 
> ---8<---
> 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@google.com>
> Fixes: 5f24f41e8ea6 ("xfrm: Remove inner/outer modes from input path")
> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Applied, thanks a lot Herbert!
diff mbox series

Patch

diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 815b38080401..d5ee96789d4b 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -180,6 +180,8 @@  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;
@@ -232,6 +234,8 @@  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;
 
@@ -267,6 +271,8 @@  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;
 
@@ -296,6 +302,8 @@  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 @@  xfrm_inner_mode_encap_remove(struct xfrm_state *x,
 			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);
 }