linux-kernel - Re: [PATCH 0/3] exporting capability name/code pairs (for 2.6.26)

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: <20080423053726.GF3861@localhost.localdomain>
Date:	Tue, 22 Apr 2008 22:37:26 -0700
From:	Chris Wright <chrisw@...s-sol.org>
To:	KaiGai Kohei <kaigai@...jp.nec.com>
Cc:	greg@...ah.com, morgan@...nel.org, serue@...ibm.com,
	chrisw@...s-sol.org, linux-security-module@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/3] exporting capability name/code pairs (for 2.6.26)

* KaiGai Kohei (kaigai@...jp.nec.com) wrote:
> [PATCH 2/3] exporting capability name/code pairs
> 
> This patch enables to export code/name pairs of capabilities the running
> kernel supported.
> 
> A newer kernel sometimes adds new capabilities, like CAP_MAC_ADMIN
> at 2.6.25. However, we have no interface to disclose what capabilities
> are supported on the running kernel. Thus, we have to maintain libcap
> version in appropriate one synchronously.
> 
> This patch enables libcap to collect the list of capabilities at run time,
> and provide them for users. It helps to improve portability of library.
> 
> It exports these information as regular files under /sys/kernel/capability.
> The numeric node exports its name, the symbolic node exports its code.

I do not understand why this is necessary.  The capability bits are an ABI
that shouldn't change in a non-backward compat way (i.e. only additions).

We typically don't export strings <-> number conversions for constants.
I know you've explained this a few times before, but it still seems to me
like a userspace only problem.  What can userspace do with a capability
it does not know about?

thanks,
-chris
--
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/