linux-kernel - Re: [PATCH] netlink: fix append of whole original message on negative ack.

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

Date:	Fri, 24 Oct 2008 00:55:43 +0400
From:	Evgeniy Polyakov <zbr@...emap.net>
To:	David Miller <davem@...emloft.net>
Cc:	michellammertink@...il.com, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org
Subject: Re: [PATCH] netlink: fix append of whole original message on negative ack.

Hi.

On Thu, Oct 23, 2008 at 01:45:13PM -0700, David Miller (davem@...emloft.net) wrote:
> > Netlink can return an negative acknowledgement, which AFAICT should include an error code and the whole original message. This patch fixes the size argument given to the __nlmsg_put call. Without this patch only the original header was attached.
> > ---
> > 
> > Can anyone explain to me why struct nlmsgerr contains an int error and the nlmsghdr struct. The comment in netlink_ack states that the whole message should be appended. Why not only include an int error in struct nlmsgerr and just append the original message?

Having header (even seq/pid only) is enough to find a message
for that userspace which cares. Looks like your patch can break
existing applications which are used to work with header only,
even if that was a mistake? Although application is supposed to
check the length, it still can expect only a header. I have to
note, that I do not know any such application though.

-- 
	Evgeniy Polyakov
--
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/