From: Kyle Moffett <mrmacman_g4@mac.com>
To: Tetsuo Handa <from-linux-kernel@i-love.sakura.ne.jp>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Is CAP_SYS_ADMIN checked by every program !?
Date: Thu, 30 Dec 2004 00:35:06 -0500 [thread overview]
Message-ID: <9033584D-5A24-11D9-989E-000393ACC76E@mac.com> (raw)
In-Reply-To: <200412291347.JEH41956.OOtStPFFNMLJVGMYS@i-love.sakura.ne.jp>
On Dec 28, 2004, at 23:47, Tetsuo Handa wrote:
> It seems to me that every program calls capable(CAP_SYS_ADMIN),
Umm, the program has nothing to do with this. Programs themselves have
no
access to the kernel function "capable". Probably something in the
kernel, perhaps
triggered by libc or maybe just suid checks, is checking for
CAP_SYS_ADMIN. It's
harmless and irrelevant, why do you care?
> + if (cap == CAP_SYS_ADMIN) {
> + static pid_t last_pid = 0;
> + if (current->pid != last_pid) {
> + printk("euid=%d uid=%d %s %s\n",
> current->euid, current->uid, cap_raised(current->cap_effective,
> CAP_SYS_ADMIN) ? "true" : "fa
> lse", current->comm);
> + last_pid = current->pid;
> + }
> + }
Yes, whenever anything on the computer, including the kernel, checks if
a program
has a capability bit set, it will print out whether or not it does in
the dmesg. Why
does that matter?
> I can't understand why every program checks for CAP_SYS_ADMIN .
Programs aren't, the kernel is, for whatever reason.
Cheers,
Kyle Moffett
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
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L++++(+++) E W++(+) N+++(++) o? K? w--- O? M++ V? PS+() PE+(-) Y+
PGP+++ t+(+++) 5 X R? tv-(--) b++++(++) DI+ D+ G e->++++$ h!*()>++$ r
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next prev parent reply other threads:[~2004-12-30 5:35 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-29 4:47 Is CAP_SYS_ADMIN checked by every program !? Tetsuo Handa
2004-12-30 3:52 ` Walter Liu
2004-12-30 4:45 ` Bernd Eckenfels
2004-12-30 5:35 ` Kyle Moffett [this message]
2004-12-30 5:46 ` Valdis.Kletnieks
2004-12-30 6:13 ` Bernd Eckenfels
2004-12-30 7:40 ` Tetsuo Handa
2004-12-30 8:24 ` Bernd Eckenfels
2005-01-03 13:52 ` Stephen Smalley
2004-12-30 13:37 ` Tetsuo Handa
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