netdev - Re: [PATCH] MD5: don't warn when an unexpected signature is seen.

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Date:	Wed, 30 Jul 2008 12:16:00 +0200
From:	Ingo Oeser <netdev@...eo.de>
To:	David Miller <davem@...emloft.net>
Cc:	agl@...erialviolet.org, netdev@...r.kernel.org
Subject: Re: [PATCH] MD5: don't warn when an unexpected signature is seen.

Hi David,

great that you did this! Counters are much better than messages here :-)
But you might find this will not compile. Details below.

David Miller schrieb:
> diff --git a/include/linux/snmp.h b/include/linux/snmp.h
> index 5df62ef..7a6e6bb 100644
> --- a/include/linux/snmp.h
> +++ b/include/linux/snmp.h
> @@ -214,6 +214,8 @@ enum
>  	LINUX_MIB_TCPDSACKIGNOREDOLD,		/* TCPSACKIgnoredOld */
>  	LINUX_MIB_TCPDSACKIGNOREDNOUNDO,	/* TCPSACKIgnoredNoUndo */
>  	LINUX_MIB_TCPSPURIOUSRTOS,		/* TCPSpuriousRTOs */
> +	LINUX_MIB_TCPMD5NOTFOUND,		/* TCPMD5NotFound */
> +	LINUX_MIB_TCPMD5UNEXPECTED,		/* TCPMD5Unexpected */

These contain "_TCP" in the name.

>  	__LINUX_MIB_MAX
>  };
>  
> diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
> index 834356e..8f5a403 100644
> --- a/net/ipv4/proc.c
> +++ b/net/ipv4/proc.c
> @@ -232,6 +232,8 @@ static const struct snmp_mib snmp4_net_list[] = {
>  	SNMP_MIB_ITEM("TCPDSACKIgnoredOld", LINUX_MIB_TCPDSACKIGNOREDOLD),
>  	SNMP_MIB_ITEM("TCPDSACKIgnoredNoUndo", LINUX_MIB_TCPDSACKIGNOREDNOUNDO),
>  	SNMP_MIB_ITEM("TCPSpuriousRTOs", LINUX_MIB_TCPSPURIOUSRTOS),
> +	SNMP_MIB_ITEM("TCPMD5NotFound", LINUX_MIB_TCPMD5NOTFOUND),
> +	SNMP_MIB_ITEM("TCPMD5Unexpected", LINUX_MIB_TCPMD5UNEXPECTED),

These contain "_TCP" in the name, too.

>  	SNMP_MIB_SENTINEL
>  };
>  
> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> index a2b06d0..4607ec1 100644
> --- a/net/ipv4/tcp_ipv4.c
> +++ b/net/ipv4/tcp_ipv4.c
> @@ -1116,18 +1116,12 @@ static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
>  		return 0;
>  
>  	if (hash_expected && !hash_location) {
> -		LIMIT_NETDEBUG(KERN_INFO "MD5 Hash expected but NOT found "
> -			       "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
> -			       NIPQUAD(iph->saddr), ntohs(th->source),
> -			       NIPQUAD(iph->daddr), ntohs(th->dest));
> +		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_MD5NOTFOUND);

This doesn't contain "_TCP" in the name. Why?

>  		return 1;
>  	}
>  
>  	if (!hash_expected && hash_location) {
> -		LIMIT_NETDEBUG(KERN_INFO "MD5 Hash NOT expected but found "
> -			       "(" NIPQUAD_FMT ", %d)->(" NIPQUAD_FMT ", %d)\n",
> -			       NIPQUAD(iph->saddr), ntohs(th->source),
> -			       NIPQUAD(iph->daddr), ntohs(th->dest));
> +		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_MD5UNEXPECTED);

This doesn't contain "_TCP" in the name. Why?

>  		return 1;
>  	}
>  
> diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
> index cff778b..0ab09c6 100644
> --- a/net/ipv6/tcp_ipv6.c
> +++ b/net/ipv6/tcp_ipv6.c
> @@ -849,28 +849,17 @@ static int tcp_v6_inbound_md5_hash (struct sock *sk, struct sk_buff *skb)
>  	hash_expected = tcp_v6_md5_do_lookup(sk, &ip6h->saddr);
>  	hash_location = tcp_parse_md5sig_option(th);
>  
> -	/* do we have a hash as expected? */
> -	if (!hash_expected) {
> -		if (!hash_location)
> -			return 0;
> -		if (net_ratelimit()) {
> -			printk(KERN_INFO "MD5 Hash NOT expected but found "
> -			       "(" NIP6_FMT ", %u)->"
> -			       "(" NIP6_FMT ", %u)\n",
> -			       NIP6(ip6h->saddr), ntohs(th->source),
> -			       NIP6(ip6h->daddr), ntohs(th->dest));
> -		}
> +	/* We've parsed the options - do we have a hash? */
> +	if (!hash_expected && !hash_location)
> +		return 0;
> +
> +	if (hash_expected && !hash_location) {
> +		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_MD5NOTFOUND);

This doesn't contain "_TCP" in the name. Why?

>  		return 1;
>  	}
>  
> -	if (!hash_location) {
> -		if (net_ratelimit()) {
> -			printk(KERN_INFO "MD5 Hash expected but NOT found "
> -			       "(" NIP6_FMT ", %u)->"
> -			       "(" NIP6_FMT ", %u)\n",
> -			       NIP6(ip6h->saddr), ntohs(th->source),
> -			       NIP6(ip6h->daddr), ntohs(th->dest));
> -		}
> +	if (!hash_expected && hash_location) {
> +		NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_MD5UNEXPECTED);

This doesn't contain "_TCP" in the name. Why?

>  		return 1;
>  	}
>  

Best Regards

Ingo Oeser
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