linux-kernel - Re: [ 82/89] netfilter: xt_hashlimit: fix race that results in duplicated entries

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-next>] [day] [month] [year] [list]

Message-ID: <20130201163455.GB4908@localhost>
Date:	Fri, 1 Feb 2013 17:34:55 +0100
From:	Pablo Neira Ayuso <pablo@...filter.org>
To:	Feng Gao <gfree.wind@...il.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [ 82/89] netfilter: xt_hashlimit: fix race that results in
 duplicated entries

On Fri, Feb 01, 2013 at 11:04:36PM +0800, Feng Gao wrote:
>    Hi Greg,
>    I have a question.
>    There are two duplicated lines now.
>                           dh->expires = now +
>    msecs_to_jiffies(hinfo->cfg.expire);
>                           rateinfo_recalc(dh, now, hinfo->cfg.mode);
>    1# case: The dsthash_find return a valid dh;
>    2# case: There is a race. The race is true.
>    Why we could not adopt the method I sent before.
>        dh = dsthash_find(hinfo, &dst);
>        if (dh == NULL) {
>            dh = dsthash_alloc_init(hinfo, &dst, &new_node);
>            if (dh == NULL) {
>                rcu_read_unlock_bh();
>                goto hotdrop;
>            }
>        }
>        if (new_node) {
>            dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
>            rateinfo_init(dh, hinfo);
>        } else {
>            /* update expiration timeout */
>            dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
>            rateinfo_recalc(dh, now, hinfo->cfg.mode);
>        }
>    I think it could avoid the two duplicated lines.

That's a cleanup, send me a follow up patch for that if you want.

Greg, please, don't back down this patch, it's fixing a real problem.

Gao is proposing some code refactoring to save line a couple of lines
of code.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/