From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>,
Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Chen Gang <gang.chen@asianux.com>,
Kees Cook <keescook@chromium.org>,
Al Viro <viro@zeniv.linux.org.uk>,
holt@sgi.com, Andrew Morton <akpm@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] kernel/sys.c: return the current gid when error occurs
Date: Wed, 7 Aug 2013 18:21:47 +0200 [thread overview]
Message-ID: <20130807162147.GA31460@redhat.com> (raw)
In-Reply-To: <52015ADB.30408@mit.edu>
On 08/06, Andy Lutomirski wrote:
>
> I assume that what the man page means is that the return value is
> whatever fsgid was prior to the call. On error, fsgid isn't changed, so
> the return value is still "current".
Probably... Still
On success, the previous value of fsuid is returned.
On error, the current value of fsuid is returned.
looks confusing. sys_setfsuid() always returns the old value.
> (FWIW, this behavior is awful and is probably the cause of a security
> bug or three, since success and failure are indistinguishable.
At least this all looks strange.
I dunno if we can change this old behaviour. I won't be surprized
if someone already uses setfsuid(-1) as getfsuid().
And perhaps the man page should be changed. Add Michael.
Oleg.
next prev parent reply other threads:[~2013-08-07 16:27 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-06 8:00 [PATCH 0/2] kernel/sys.c: for setfsgid(), return the current gid when error occurs Chen Gang
2013-08-06 8:01 ` [PATCH 1/2] kernel/sys.c: " Chen Gang
2013-08-06 20:21 ` Andy Lutomirski
2013-08-07 3:30 ` Chen Gang
2013-08-07 16:21 ` Oleg Nesterov [this message]
2013-08-07 16:58 ` Andy Lutomirski
2013-08-08 1:30 ` Chen Gang
2013-08-08 1:35 ` Andy Lutomirski
2013-08-08 1:48 ` Chen Gang
2013-08-08 13:52 ` Michael Kerrisk (man-pages)
2013-08-09 0:55 ` Chen Gang
2013-08-08 13:37 ` Michael Kerrisk (man-pages)
2013-08-09 0:59 ` Chen Gang
2013-08-09 7:27 ` Michael Kerrisk (man-pages)
2013-08-06 8:02 ` [PATCH 2/2] kernel/sys.c: remove useless variable 'old_fsgid' for setfsgid() Chen Gang
2013-08-06 8:56 ` Chen Gang
2013-08-06 8:13 ` kernel/sys.c: for setfsuid(), return the current uid when error occurs Chen Gang
2013-08-06 8:14 ` Chen Gang
2013-08-06 8:15 ` [PATCH 0/2] " Chen Gang
2013-08-06 8:15 ` [PATCH 1/2] kernel/sys.c: " Chen Gang
2013-08-06 8:16 ` [PATCH 2/2] kernel/sys.c: remove useless variable 'old_fsuid' for setfsuid() Chen Gang
2013-08-06 8:55 ` Chen Gang
2013-08-06 8:43 ` [PATCH] kernel/sys.c: improve the usage of return value Chen Gang
2013-08-07 10:44 ` Chen Gang
2013-08-06 18:36 ` [PATCH 0/2] kernel/sys.c: for setfsgid(), return the current gid when error occurs Kees Cook
2013-08-07 2:25 ` Chen Gang
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