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  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]
Date:   Wed, 29 Nov 2017 13:46:12 +0000
From:   Alan Cox <>
To:     Kees Cook <>
Cc:     "Luis R. Rodriguez" <>,
        Djalal Harouni <>,
        Andy Lutomirski <>,
        Andrew Morton <>,
        James Morris <>,
        Ben Hutchings <>,
        Solar Designer <>,
        Serge Hallyn <>, Jessica Yu <>,
        Rusty Russell <>,
        LKML <>,
        linux-security-module <>,,
        Jonathan Corbet <>,
        Ingo Molnar <>,
        "David S. Miller" <>,
        Network Development <>,
        Peter Zijlstra <>,
        Linus Torvalds <>
Subject: Re: [PATCH v5 next 1/5] modules:capabilities: add

On Tue, 28 Nov 2017 13:39:58 -0800
Kees Cook <> wrote:

> On Tue, Nov 28, 2017 at 1:16 PM, Luis R. Rodriguez <> wrote:
> > And *all* auto-loading uses aliases? What's the difference between auto-loading
> > and direct-loading?  
> The difference is the process privileges. Unprivilged autoloading
> (e.g. int n_hdlc = N_HDLC; ioctl(fd,
> TIOCSETD, &n_hdlc)), triggers a privileged call to finit_module()

If you have CAP_SYS_DAC you can rename any module to ppp.ko and ask the
network manager (which has the right permissions) to init a ppp
connection. Capabilities alone are simply not enough to do any kind of
useful protection on a current system and the Linux capability model is
broken architecturally and not fixable because fixing it would break lots
of real systems.

I really don't care what the module loading rules end up with and whether
we add CAP_SYS_YET_ANOTHER_MEANINGLESS_FLAG but what is actually needed
is to properly incorporate it into securiy ruiles for whatever LSM you
are using.


Powered by blists - more mailing lists