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* [lvc-project] [PATCH] netfilter: nfnetlink: NULL-check skb->dev in __build_packet_message()
@ 2023-03-27  9:41 Igor Artemiev
  2023-03-27 10:22 ` Pablo Neira Ayuso
  0 siblings, 1 reply; 3+ messages in thread
From: Igor Artemiev @ 2023-03-27  9:41 UTC (permalink / raw)
  To: Pablo Neira Ayuso
  Cc: Igor Artemiev, Jozsef Kadlecsik, Florian Westphal,
	David S . Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
	netfilter-devel, coreteam, netdev, linux-kernel

After having been compared to NULL value at nfnetlink_log.c:560,
pointer 'skb->dev' is dereferenced at nfnetlink_log.c:576.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Signed-off-by: Igor Artemiev <Igor.A.Artemiev@mcst.ru>
---
 net/netfilter/nfnetlink_log.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index d97eb280cb2e..2711509eb9a5 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -572,7 +572,7 @@ __build_packet_message(struct nfnl_log_net *log,
 		}
 	}
 
-	if (indev && skb_mac_header_was_set(skb)) {
+	if (indev && skb->dev && skb_mac_header_was_set(skb)) {
 		if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
 		    nla_put_be16(inst->skb, NFULA_HWLEN,
 				 htons(skb->dev->hard_header_len)))
-- 
2.30.2


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [lvc-project] [PATCH] netfilter: nfnetlink: NULL-check skb->dev in __build_packet_message()
  2023-03-27  9:41 [lvc-project] [PATCH] netfilter: nfnetlink: NULL-check skb->dev in __build_packet_message() Igor Artemiev
@ 2023-03-27 10:22 ` Pablo Neira Ayuso
  2023-03-27 15:09   ` Igor A. Artemiev
  0 siblings, 1 reply; 3+ messages in thread
From: Pablo Neira Ayuso @ 2023-03-27 10:22 UTC (permalink / raw)
  To: Igor Artemiev
  Cc: Jozsef Kadlecsik, Florian Westphal, David S . Miller,
	Eric Dumazet, Jakub Kicinski, Paolo Abeni, netfilter-devel,
	coreteam, netdev, linux-kernel

On Mon, Mar 27, 2023 at 12:41:16PM +0300, Igor Artemiev wrote:
> After having been compared to NULL value at nfnetlink_log.c:560,
> pointer 'skb->dev' is dereferenced at nfnetlink_log.c:576.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Igor Artemiev <Igor.A.Artemiev@mcst.ru>
> ---
>  net/netfilter/nfnetlink_log.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
> index d97eb280cb2e..2711509eb9a5 100644
> --- a/net/netfilter/nfnetlink_log.c
> +++ b/net/netfilter/nfnetlink_log.c
> @@ -572,7 +572,7 @@ __build_packet_message(struct nfnl_log_net *log,
>  		}
>  	}
>  
> -	if (indev && skb_mac_header_was_set(skb)) {
> +	if (indev && skb->dev && skb_mac_header_was_set(skb)) {

This cannot ever happen, we assume skb->dev is always set on.

>  		if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
>  		    nla_put_be16(inst->skb, NFULA_HWLEN,
>  				 htons(skb->dev->hard_header_len)))
> -- 
> 2.30.2
> 

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [lvc-project] [PATCH] netfilter: nfnetlink: NULL-check skb->dev in __build_packet_message()
  2023-03-27 10:22 ` Pablo Neira Ayuso
@ 2023-03-27 15:09   ` Igor A. Artemiev
  0 siblings, 0 replies; 3+ messages in thread
From: Igor A. Artemiev @ 2023-03-27 15:09 UTC (permalink / raw)
  To: Pablo Neira Ayuso
  Cc: Jozsef Kadlecsik, Florian Westphal, David S . Miller,
	Eric Dumazet, Jakub Kicinski, Paolo Abeni, netfilter-devel,
	coreteam, netdev, linux-kernel, lvc-project


On 3/27/23 13:22, Pablo Neira Ayuso wrote:
> On Mon, Mar 27, 2023 at 12:41:16PM +0300, Igor Artemiev wrote:
>> After having been compared to NULL value at nfnetlink_log.c:560,
>> pointer 'skb->dev' is dereferenced at nfnetlink_log.c:576.
>>
>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>>
>> Signed-off-by: Igor Artemiev <Igor.A.Artemiev@mcst.ru>
>> ---
>>   net/netfilter/nfnetlink_log.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
>> index d97eb280cb2e..2711509eb9a5 100644
>> --- a/net/netfilter/nfnetlink_log.c
>> +++ b/net/netfilter/nfnetlink_log.c
>> @@ -572,7 +572,7 @@ __build_packet_message(struct nfnl_log_net *log,
>>   		}
>>   	}
>>   
>> -	if (indev && skb_mac_header_was_set(skb)) {
>> +	if (indev && skb->dev && skb_mac_header_was_set(skb)) {
> This cannot ever happen, we assume skb->dev is always set on.
>
>>   		if (nla_put_be16(inst->skb, NFULA_HWTYPE, htons(skb->dev->type)) ||
>>   		    nla_put_be16(inst->skb, NFULA_HWLEN,
>>   				 htons(skb->dev->hard_header_len)))
>> -- 
>> 2.30.2
>>

If skb->dev is always set on, should the check at nfnetlink_log.c:560 be removed?
|

if  (indev  &&  skb->dev  &&
	skb_mac_header_was_set(skb)  &&
	    	skb_mac_header_len(skb)  !=  0)  { |

||Thanks, Igor


^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2023-03-27 15:06 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2023-03-27  9:41 [lvc-project] [PATCH] netfilter: nfnetlink: NULL-check skb->dev in __build_packet_message() Igor Artemiev
2023-03-27 10:22 ` Pablo Neira Ayuso
2023-03-27 15:09   ` Igor A. Artemiev

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