linux-kernel - Re: New Security Features, Please Comment

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]

Message-ID: <20081205034402.GB1626@mail.local.tull.net>
Date:	Fri, 5 Dec 2008 14:44:02 +1100
From:	Nick Andrew <nick@...k-andrew.net>
To:	Valdis.Kletnieks@...edu
Cc:	Geoffrey McRae <geoff@...idhost.com>,
	Peter Teoh <htmldeveloper@...il.com>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	linux-kernel@...r.kernel.org
Subject: Re: New Security Features, Please Comment

On Thu, Dec 04, 2008 at 10:35:27PM -0500, Valdis.Kletnieks@...edu wrote:
> You're also overlooking the fact that the malicious code could do something
> like this:
> 
> 	/* send the parent something that makes it *think* the request finished */
> 	printf("We're all done now\n");
> 	while (getpid()) msleep (1);

I think it's pretty basic that setgid/setuid needs to be done _before_
exec'ing untrusted code.

On the other hand, if a trusted process gets its uid changed _and_
expects this to happen then I suppose it can be secure. But if a
process's uid gets changed unexpectedly then nasty things already
pointed out by Alan and others can occur.

Nick.
-- 
PGP Key ID = 0x418487E7                      http://www.nick-andrew.net/
PGP Key fingerprint = B3ED 6894 8E49 1770 C24A  67E3 6266 6EB9 4184 87E7
--
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/