Patchwork [net] net: flow_dissector: fail on evil iph->ihl

login
register
mail settings
Submitter Jason Wang
Date Nov. 1, 2013, 7:01 a.m.
Message ID <1383289270-18952-1-git-send-email-jasowang@redhat.com>
Download mbox | patch
Permalink /patch/287709/
State Accepted
Delegated to: David Miller
Headers show

Comments

Jason Wang - Nov. 1, 2013, 7:01 a.m.
We don't validate iph->ihl which may lead a dead loop if we meet a IPIP
skb whose iph->ihl is zero. Fix this by failing immediately when iph->ihl
is evil (less than 5).

This issue were introduced by commit ec5efe7946280d1e84603389a1030ccec0a767ae
(rps: support IPIP encapsulation).

Cc: Eric Dumazet <edumazet@google.com>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
This patch is needed for stable.
---
 net/core/flow_dissector.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Eric Dumazet - Nov. 1, 2013, 9:48 a.m.
On Fri, 2013-11-01 at 15:01 +0800, Jason Wang wrote:
> We don't validate iph->ihl which may lead a dead loop if we meet a IPIP
> skb whose iph->ihl is zero. Fix this by failing immediately when iph->ihl
> is evil (less than 5).
> 
> This issue were introduced by commit ec5efe7946280d1e84603389a1030ccec0a767ae
> (rps: support IPIP encapsulation).
> 
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Petr Matousek <pmatouse@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> This patch is needed for stable.
> ---

Acked-by: Eric Dumazet <edumazet@google.com>

Thanks Jason !


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Ben Hutchings - Nov. 1, 2013, 4:29 p.m.
On Fri, 2013-11-01 at 15:01 +0800, Jason Wang wrote:
> We don't validate iph->ihl which may lead a dead loop if we meet a IPIP
> skb whose iph->ihl is zero. Fix this by failing immediately when iph->ihl
> is evil (less than 5).
> 
> This issue were introduced by commit ec5efe7946280d1e84603389a1030ccec0a767ae
> (rps: support IPIP encapsulation).

It would be helpful to include the CVE ID here:

CVE-2013-4348

Ben.

> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Petr Matousek <pmatouse@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
> This patch is needed for stable.
> ---
>  net/core/flow_dissector.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
> index 8d7d0dd..143b6fd 100644
> --- a/net/core/flow_dissector.c
> +++ b/net/core/flow_dissector.c
> @@ -40,7 +40,7 @@ again:
>  		struct iphdr _iph;
>  ip:
>  		iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
> -		if (!iph)
> +		if (!iph || iph->ihl < 5)
>  			return false;
>  
>  		if (ip_is_fragment(iph))
David Miller - Nov. 2, 2013, 6:16 a.m.
From: Jason Wang <jasowang@redhat.com>
Date: Fri,  1 Nov 2013 15:01:10 +0800

> We don't validate iph->ihl which may lead a dead loop if we meet a IPIP
> skb whose iph->ihl is zero. Fix this by failing immediately when iph->ihl
> is evil (less than 5).
> 
> This issue were introduced by commit ec5efe7946280d1e84603389a1030ccec0a767ae
> (rps: support IPIP encapsulation).
> 
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Petr Matousek <pmatouse@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Applied and queued up for -stable, thanks Jason.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Michael S. Tsirkin - Nov. 2, 2013, 8:22 p.m.
On Fri, Nov 01, 2013 at 03:01:10PM +0800, Jason Wang wrote:
> We don't validate iph->ihl which may lead a dead loop if we meet a IPIP
> skb whose iph->ihl is zero. Fix this by failing immediately when iph->ihl
> is evil (less than 5).
> 
> This issue were introduced by commit ec5efe7946280d1e84603389a1030ccec0a767ae
> (rps: support IPIP encapsulation).
> 
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Petr Matousek <pmatouse@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>


Acked-by: Michael S. Tsirkin <mst@redhat.com>

> ---
> This patch is needed for stable.
> ---
>  net/core/flow_dissector.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
> index 8d7d0dd..143b6fd 100644
> --- a/net/core/flow_dissector.c
> +++ b/net/core/flow_dissector.c
> @@ -40,7 +40,7 @@ again:
>  		struct iphdr _iph;
>  ip:
>  		iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
> -		if (!iph)
> +		if (!iph || iph->ihl < 5)
>  			return false;
>  
>  		if (ip_is_fragment(iph))
> -- 
> 1.8.1.2
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Daniel Borkmann - Nov. 3, 2013, 10:18 p.m.
On 11/01/2013 08:01 AM, Jason Wang wrote:
> We don't validate iph->ihl which may lead a dead loop if we meet a IPIP
> skb whose iph->ihl is zero. Fix this by failing immediately when iph->ihl
> is evil (less than 5).
>
> This issue were introduced by commit ec5efe7946280d1e84603389a1030ccec0a767ae
> (rps: support IPIP encapsulation).
>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Petr Matousek <pmatouse@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Daniel Borkmann <dborkman@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Sorry, a bit late as I was offline last 4 days, but fwiw:

Acked-by: Daniel Borkmann <dborkman@redhat.com>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 8d7d0dd..143b6fd 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -40,7 +40,7 @@  again:
 		struct iphdr _iph;
 ip:
 		iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
-		if (!iph)
+		if (!iph || iph->ihl < 5)
 			return false;
 
 		if (ip_is_fragment(iph))