netdev - Re: [PATCH 2/6] socket: sk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <20080410.014938.247220159.davem@davemloft.net>
Date:	Thu, 10 Apr 2008 01:49:38 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	shemminger@...tta.com
Cc:	netdev@...r.kernel.org
Subject: Re: [PATCH 2/6] socket: sk_filter deinline

From: Stephen Hemminger <shemminger@...tta.com>
Date: Mon, 31 Mar 2008 17:47:10 -0700

> The sk_filter function is too big to be inlined. This saves 2296 bytes
> of text on allyesconfig.
> 
> Signed-off-by: Stephen Hemminger <shemminger@...tta.com>

Because of the bloat I'll apply this to net-2.6.26

But I think we can do better in many of the callsites.

Most of them are in the packet receive path, have BH's disabled, and a
lot of the variables already laid out in registers.

I would like to see a new inline created that caters to these cases,
which does something like:

	if (rcu_dereference(sk->sk_filter))
		return sk_filter(sk, skb);
	else
		return 0;

The security check muddles things here, but that should be inlined in
such situations too I think.

It's all of that "pkt_len = this; pskb_trim(that);" that makes for
most of the bloat.  And that can stay in the un-inlined sk_filter() we
have now.

Having a socket filter enabled on a TCP socket is so rare, but
now everyone pays for the function call unconditionally.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html