From: Ben Hutchings <ben@decadent.org.uk>
To: Djalal Harouni <tixxdz@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
serge@hallyn.com, kernel-hardening@lists.openwall.com,
linux-security-module@vger.kernel.org
Cc: Linux API <linux-api@vger.kernel.org>,
Dongsu Park <dpark@posteo.net>,
Casey Schaufler <casey@schaufler-ca.com>,
James Morris <james.l.morris@oracle.com>,
Paul Moore <paul@paul-moore.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jonathan Corbet <corbet@lwn.net>, Jessica Yu <jeyu@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
zendyani@gmail.com, Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v3 1/2] modules:capabilities: automatic module loading restriction
Date: Thu, 20 Apr 2017 03:22:22 +0100 [thread overview]
Message-ID: <1492654942.31767.21.camel@decadent.org.uk> (raw)
In-Reply-To: <1492640420-27345-2-git-send-email-tixxdz@gmail.com>
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On Thu, 2017-04-20 at 00:20 +0200, Djalal Harouni wrote:
[...]
> +modules_autoload:
> +
> +A sysctl to control if modules auto-load feature is allowed or not.
> +This sysctl complements "modules_disabled" which is for all module
> +operations where this flag applies only to automatic module loading.
> +Automatic module loading happens when programs request a kernel feature
> +that is implemented by an unloaded module, the kernel automatically
> +runs the program pointed by "modprobe" sysctl in order to load the
> +corresponding module.
> +
> +When modules_autoload is set to (0), the default, there are no
> +restrictions.
> +
> +When modules_autoload is set to (1), processes must have CAP_SYS_MODULE
> +to be able to trigger a module auto-load operation, or CAP_NET_ADMIN
> +for modules with a 'netdev-%s' alias.
> +
> +When modules_autoload is set to (2), automatic module loading is
> +disabled for all. Once set, this value can not be changed.
I would expect a parameter 'modules_autoload' to be a boolean, so this
behaviour would be surprising.
What is the point of mode 2? Why would someone want to set
modules_disabled=0 and modules_autoload=2?
[...]
> --- a/kernel/module.c
> +++ b/kernel/module.c
[...]
> +static int modules_autoload_privileged_access(const char *name)
> +{
> + if (capable(CAP_SYS_MODULE))
> + return 0;
> + else if (name && strstr(name, "netdev-") && capable(CAP_NET_ADMIN))
[...]
We want a prefix match, so use strncmp() not strstr().
Ben.
--
Ben Hutchings
It is easier to change the specification to fit the program than vice
versa.
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WARNING: multiple messages have this Message-ID (diff)
From: ben@decadent.org.uk (Ben Hutchings)
To: linux-security-module@vger.kernel.org
Subject: [PATCH v3 1/2] modules:capabilities: automatic module loading restriction
Date: Thu, 20 Apr 2017 03:22:22 +0100 [thread overview]
Message-ID: <1492654942.31767.21.camel@decadent.org.uk> (raw)
In-Reply-To: <1492640420-27345-2-git-send-email-tixxdz@gmail.com>
On Thu, 2017-04-20 at 00:20 +0200, Djalal Harouni wrote:
[...]?
> +modules_autoload:
> +
> +A sysctl to control if modules auto-load feature is allowed or not.
> +This sysctl complements "modules_disabled" which is for all module
> +operations where this flag applies only to automatic module loading.
> +Automatic module loading happens when programs request a kernel feature
> +that is implemented by an unloaded module, the kernel automatically
> +runs the program pointed by "modprobe" sysctl in order to load the
> +corresponding module.
> +
> +When modules_autoload is set to (0), the default, there are no
> +restrictions.
> +
> +When modules_autoload is set to (1), processes must have CAP_SYS_MODULE
> +to be able to trigger a module auto-load operation, or CAP_NET_ADMIN
> +for modules with a 'netdev-%s' alias.
> +
> +When modules_autoload is set to (2), automatic module loading is
> +disabled for all. Once set, this value can not be changed.
I would expect a parameter 'modules_autoload' to be a boolean, so this
behaviour would be surprising.
What is the point of mode 2? Why would someone want to set
modules_disabled=0 and modules_autoload=2?
[...]
> --- a/kernel/module.c
> +++ b/kernel/module.c
[...]
> +static int modules_autoload_privileged_access(const char *name)
> +{
> + if (capable(CAP_SYS_MODULE))
> + return 0;
> + else if (name && strstr(name, "netdev-") && capable(CAP_NET_ADMIN))
[...]
We want a prefix match, so use strncmp() not strstr().
Ben.
--
Ben Hutchings
It is easier to change the specification to fit the program than vice
versa.
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WARNING: multiple messages have this Message-ID (diff)
From: Ben Hutchings <ben@decadent.org.uk>
To: Djalal Harouni <tixxdz@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
serge@hallyn.com, kernel-hardening@lists.openwall.com,
linux-security-module@vger.kernel.org
Cc: Linux API <linux-api@vger.kernel.org>,
Dongsu Park <dpark@posteo.net>,
Casey Schaufler <casey@schaufler-ca.com>,
James Morris <james.l.morris@oracle.com>,
Paul Moore <paul@paul-moore.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jonathan Corbet <corbet@lwn.net>, Jessica Yu <jeyu@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
zendyani@gmail.com, Peter Zijlstra <peterz@infradead.org>
Subject: [kernel-hardening] Re: [PATCH v3 1/2] modules:capabilities: automatic module loading restriction
Date: Thu, 20 Apr 2017 03:22:22 +0100 [thread overview]
Message-ID: <1492654942.31767.21.camel@decadent.org.uk> (raw)
In-Reply-To: <1492640420-27345-2-git-send-email-tixxdz@gmail.com>
[-- Attachment #1: Type: text/plain, Size: 1630 bytes --]
On Thu, 2017-04-20 at 00:20 +0200, Djalal Harouni wrote:
[...]
> +modules_autoload:
> +
> +A sysctl to control if modules auto-load feature is allowed or not.
> +This sysctl complements "modules_disabled" which is for all module
> +operations where this flag applies only to automatic module loading.
> +Automatic module loading happens when programs request a kernel feature
> +that is implemented by an unloaded module, the kernel automatically
> +runs the program pointed by "modprobe" sysctl in order to load the
> +corresponding module.
> +
> +When modules_autoload is set to (0), the default, there are no
> +restrictions.
> +
> +When modules_autoload is set to (1), processes must have CAP_SYS_MODULE
> +to be able to trigger a module auto-load operation, or CAP_NET_ADMIN
> +for modules with a 'netdev-%s' alias.
> +
> +When modules_autoload is set to (2), automatic module loading is
> +disabled for all. Once set, this value can not be changed.
I would expect a parameter 'modules_autoload' to be a boolean, so this
behaviour would be surprising.
What is the point of mode 2? Why would someone want to set
modules_disabled=0 and modules_autoload=2?
[...]
> --- a/kernel/module.c
> +++ b/kernel/module.c
[...]
> +static int modules_autoload_privileged_access(const char *name)
> +{
> + if (capable(CAP_SYS_MODULE))
> + return 0;
> + else if (name && strstr(name, "netdev-") && capable(CAP_NET_ADMIN))
[...]
We want a prefix match, so use strncmp() not strstr().
Ben.
--
Ben Hutchings
It is easier to change the specification to fit the program than vice
versa.
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next prev parent reply other threads:[~2017-04-20 2:22 UTC|newest]
Thread overview: 147+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-19 22:20 [PATCH v3 0/2] modules:capabilities: automatic module loading restrictions Djalal Harouni
2017-04-19 22:20 ` [kernel-hardening] " Djalal Harouni
2017-04-19 22:20 ` Djalal Harouni
2017-04-19 22:20 ` Djalal Harouni
2017-04-19 22:20 ` [PATCH v3 1/2] modules:capabilities: automatic module loading restriction Djalal Harouni
2017-04-19 22:20 ` [kernel-hardening] " Djalal Harouni
2017-04-19 22:20 ` Djalal Harouni
2017-04-19 22:20 ` Djalal Harouni
2017-04-19 23:16 ` Andy Lutomirski
2017-04-19 23:16 ` [kernel-hardening] " Andy Lutomirski
2017-04-19 23:16 ` Andy Lutomirski
2017-04-19 23:16 ` Andy Lutomirski
2017-04-20 2:22 ` Ben Hutchings [this message]
2017-04-20 2:22 ` [kernel-hardening] " Ben Hutchings
2017-04-20 2:22 ` Ben Hutchings
2017-04-20 12:44 ` [kernel-hardening] " Djalal Harouni
2017-04-20 12:44 ` Djalal Harouni
2017-04-20 12:44 ` Djalal Harouni
2017-04-20 15:02 ` Ben Hutchings
2017-04-20 15:02 ` Ben Hutchings
2017-04-20 15:02 ` Ben Hutchings
2017-04-20 20:39 ` [kernel-hardening] " Djalal Harouni
2017-04-20 20:39 ` Djalal Harouni
2017-04-20 20:39 ` Djalal Harouni
2017-04-20 21:28 ` Kees Cook
2017-04-20 21:28 ` Kees Cook
2017-04-20 21:28 ` Kees Cook
2017-04-20 21:28 ` Kees Cook
2017-04-19 22:20 ` [PATCH v3 2/2] modules:capabilities: add a per-task modules autoload restriction Djalal Harouni
2017-04-19 22:20 ` [kernel-hardening] " Djalal Harouni
2017-04-19 22:20 ` Djalal Harouni
2017-04-19 22:20 ` Djalal Harouni
2017-04-19 22:38 ` Djalal Harouni
2017-04-19 22:38 ` [kernel-hardening] " Djalal Harouni
2017-04-19 22:38 ` Djalal Harouni
2017-04-19 22:38 ` Djalal Harouni
2017-04-19 23:15 ` Andy Lutomirski
2017-04-19 23:15 ` [kernel-hardening] " Andy Lutomirski
2017-04-19 23:15 ` Andy Lutomirski
2017-04-19 23:15 ` Andy Lutomirski
2017-04-19 23:43 ` Kees Cook
2017-04-19 23:43 ` [kernel-hardening] " Kees Cook
2017-04-19 23:43 ` Kees Cook
2017-04-19 23:43 ` Kees Cook
2017-04-20 2:41 ` Andy Lutomirski
2017-04-20 2:41 ` [kernel-hardening] " Andy Lutomirski
2017-04-20 2:41 ` Andy Lutomirski
2017-04-20 2:41 ` Andy Lutomirski
2017-04-21 23:19 ` Kees Cook
2017-04-21 23:19 ` [kernel-hardening] " Kees Cook
2017-04-21 23:19 ` Kees Cook
2017-04-21 23:19 ` Kees Cook
2017-04-21 23:28 ` Andy Lutomirski
2017-04-21 23:28 ` [kernel-hardening] " Andy Lutomirski
2017-04-21 23:28 ` Andy Lutomirski
2017-04-21 23:28 ` Andy Lutomirski
2017-04-21 23:40 ` Kees Cook
2017-04-21 23:40 ` [kernel-hardening] " Kees Cook
2017-04-21 23:40 ` Kees Cook
2017-04-21 23:40 ` Kees Cook
2017-04-21 23:51 ` Andy Lutomirski
2017-04-21 23:51 ` [kernel-hardening] " Andy Lutomirski
2017-04-21 23:51 ` Andy Lutomirski
2017-04-21 23:51 ` Andy Lutomirski
2017-04-22 0:12 ` Djalal Harouni
2017-04-22 0:12 ` [kernel-hardening] " Djalal Harouni
2017-04-22 0:12 ` Djalal Harouni
2017-04-22 0:12 ` Djalal Harouni
2017-04-22 1:19 ` Djalal Harouni
2017-04-22 1:19 ` [kernel-hardening] " Djalal Harouni
2017-04-22 1:19 ` Djalal Harouni
2017-04-22 1:19 ` Djalal Harouni
2017-04-22 6:51 ` Andy Lutomirski
2017-04-22 6:51 ` [kernel-hardening] " Andy Lutomirski
2017-04-22 6:51 ` Andy Lutomirski
2017-04-22 6:51 ` Andy Lutomirski
2017-04-22 19:29 ` Kees Cook
2017-04-22 19:29 ` [kernel-hardening] " Kees Cook
2017-04-22 19:29 ` Kees Cook
2017-04-22 19:29 ` Kees Cook
2017-04-24 14:25 ` Djalal Harouni
2017-04-24 14:25 ` [kernel-hardening] " Djalal Harouni
2017-04-24 14:25 ` Djalal Harouni
2017-04-24 14:25 ` Djalal Harouni
2017-04-24 18:02 ` Kees Cook
2017-04-24 18:02 ` [kernel-hardening] " Kees Cook
2017-04-24 18:02 ` Kees Cook
2017-04-24 18:02 ` Kees Cook
2017-04-24 18:35 ` Djalal Harouni
2017-04-24 18:35 ` [kernel-hardening] " Djalal Harouni
2017-04-24 18:35 ` Djalal Harouni
2017-04-24 18:35 ` Djalal Harouni
2017-04-21 23:52 ` Casey Schaufler
2017-04-21 23:52 ` [kernel-hardening] " Casey Schaufler
2017-04-21 23:52 ` Casey Schaufler
2017-04-21 23:52 ` Casey Schaufler
2017-04-22 0:00 ` Andy Lutomirski
2017-04-22 0:00 ` [kernel-hardening] " Andy Lutomirski
2017-04-22 0:00 ` Andy Lutomirski
2017-04-22 0:00 ` Andy Lutomirski
2017-04-22 0:13 ` Casey Schaufler
2017-04-22 0:13 ` [kernel-hardening] " Casey Schaufler
2017-04-22 0:13 ` Casey Schaufler
2017-04-22 0:13 ` Casey Schaufler
2017-04-22 6:45 ` Andy Lutomirski
2017-04-22 6:45 ` [kernel-hardening] " Andy Lutomirski
2017-04-22 6:45 ` Andy Lutomirski
2017-04-22 6:45 ` Andy Lutomirski
2017-04-22 12:17 ` Djalal Harouni
2017-04-22 12:17 ` [kernel-hardening] " Djalal Harouni
2017-04-22 12:17 ` Djalal Harouni
2017-04-22 12:17 ` Djalal Harouni
2017-05-04 13:07 ` Djalal Harouni
2017-05-04 13:07 ` [kernel-hardening] " Djalal Harouni
2017-05-04 13:07 ` Djalal Harouni
2017-05-04 13:07 ` Djalal Harouni
2017-05-04 14:58 ` Serge E. Hallyn
2017-05-04 14:58 ` [kernel-hardening] " Serge E. Hallyn
2017-05-04 14:58 ` Serge E. Hallyn
2017-05-04 14:58 ` Serge E. Hallyn
2017-05-05 13:06 ` Djalal Harouni
2017-05-05 13:06 ` [kernel-hardening] " Djalal Harouni
2017-05-05 13:06 ` Djalal Harouni
2017-05-05 13:06 ` Djalal Harouni
2017-05-05 16:18 ` Andy Lutomirski
2017-05-05 16:18 ` [kernel-hardening] " Andy Lutomirski
2017-05-05 16:18 ` Andy Lutomirski
2017-05-05 16:18 ` Andy Lutomirski
2017-04-20 1:57 ` kbuild test robot
2017-04-20 1:57 ` [kernel-hardening] " kbuild test robot
2017-04-20 1:57 ` kbuild test robot
2017-04-20 1:57 ` kbuild test robot
2017-04-24 4:29 ` Rusty Russell
2017-04-24 4:29 ` [kernel-hardening] " Rusty Russell
2017-04-24 4:29 ` Rusty Russell
2017-04-24 4:29 ` Rusty Russell
2017-04-26 9:06 ` Djalal Harouni
2017-04-26 9:06 ` [kernel-hardening] " Djalal Harouni
2017-04-26 9:06 ` Djalal Harouni
2017-04-27 2:07 ` Rusty Russell
2017-04-27 2:07 ` [kernel-hardening] " Rusty Russell
2017-04-27 2:07 ` Rusty Russell
2017-04-27 2:07 ` Rusty Russell
2017-04-27 13:16 ` Djalal Harouni
2017-04-27 13:16 ` [kernel-hardening] " Djalal Harouni
2017-04-27 13:16 ` Djalal Harouni
2017-04-27 13:16 ` Djalal Harouni
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