linux-kernel - RE: [RFC PATCH 0/1] security: add SECURE_KEEP_FSUID to preserve fsuid/fsgid across execve

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: <127af0e711e747279742b2aa13a658fb@ustx2ex-dag1mb5.msg.corp.akamai.com>
Date:   Wed, 3 Jul 2019 00:58:34 +0000
From:   "Lubashev, Igor" <ilubashe@...mai.com>
To:     James Morris <jmorris@...ei.org>
CC:     Serge Hallyn <serge@...lyn.com>,
        "linux-security-module@...r.kernel.org" 
        <linux-security-module@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [RFC PATCH 0/1] security: add SECURE_KEEP_FSUID to preserve
 fsuid/fsgid across execve

> From: James Morris <jmorris@...ei.org>  on Friday, June 14, 2019 11:54 PM:
> On Sat, 15 Jun 2019, Lubashev, Igor wrote:
> 
> > Unfortunately, perf is using uid==0 and euid==0 as a "capability bits".
> >
> >
> > In tools/perf/util/evsel.c:
> > 	static bool perf_event_can_profile_kernel(void)
> > 	{
> > 		return geteuid() == 0 || perf_event_paranoid() == -1;
> > 	}
> >
> > In tools/perf/util/symbol.c:
> > 	static bool symbol__read_kptr_restrict(void)
> > 	{
> > 	...
> > 		value = ((geteuid() != 0) || (getuid() != 0)) ?
> > 				(atoi(line) != 0) :
> > 				(atoi(line) == 2);
> > 	...
> > 	}
> 
> These are bugs. They should be checking for CAP_SYS_ADMIN.

Thanks for the suggestion.

Actually, the former one should be checking CAP_SYS_ADMIN, while the latter -- CAP_SYSLOG (see lib/vsprintf.c).

Just posted a patch to perf (http://lists.infradead.org/pipermail/linux-arm-kernel/2019-July/664552.html).

Thank you,

- Igor