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From: ebiederm@xmission.com (Eric W. Biederman)
To: Amerigo Wang <amwang@redhat.com>
Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org
Subject: Re: [Patch] kexec_load: check CAP_SYS_MODULE
Date: Thu, 06 Jan 2011 00:47:00 -0800	[thread overview]
Message-ID: <m1bp3uifln.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <1294302325-22593-1-git-send-email-amwang@redhat.com> (Amerigo Wang's message of "Thu, 6 Jan 2011 16:25:25 +0800")

Amerigo Wang <amwang@redhat.com> writes:

> Eric pointed out that kexec_load() actually allows you to
> run any code you want in ring0, this is more like CAP_SYS_MODULE.

Let me get this straight you want to make the permission checks
less stringent by allowing either CAP_SYS_MODULE or CAP_SYS_BOOT?

CAP_SYS_BOOT is the correct capability.  Sure you can run any
code but only after rebooting.  I don't see how this differs
from any other reboot scenario.

Eric


> Reported-by: Eric Paris <eparis@redhat.com>
> Signed-off-by: WANG Cong <amwang@redhat.com>
>
> ---
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index b55045b..c30d613 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -945,7 +945,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
>  	int result;
>  
>  	/* We only trust the superuser with rebooting the system. */
> -	if (!capable(CAP_SYS_BOOT))
> +	if (!capable(CAP_SYS_BOOT) || !capable(CAP_SYS_MODULE))
>  		return -EPERM;
>  
>  	/*

WARNING: multiple messages have this Message-ID (diff)
From: ebiederm@xmission.com (Eric W. Biederman)
To: Amerigo Wang <amwang@redhat.com>
Cc: kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [Patch] kexec_load: check CAP_SYS_MODULE
Date: Thu, 06 Jan 2011 00:47:00 -0800	[thread overview]
Message-ID: <m1bp3uifln.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <1294302325-22593-1-git-send-email-amwang@redhat.com> (Amerigo Wang's message of "Thu, 6 Jan 2011 16:25:25 +0800")

Amerigo Wang <amwang@redhat.com> writes:

> Eric pointed out that kexec_load() actually allows you to
> run any code you want in ring0, this is more like CAP_SYS_MODULE.

Let me get this straight you want to make the permission checks
less stringent by allowing either CAP_SYS_MODULE or CAP_SYS_BOOT?

CAP_SYS_BOOT is the correct capability.  Sure you can run any
code but only after rebooting.  I don't see how this differs
from any other reboot scenario.

Eric


> Reported-by: Eric Paris <eparis@redhat.com>
> Signed-off-by: WANG Cong <amwang@redhat.com>
>
> ---
> diff --git a/kernel/kexec.c b/kernel/kexec.c
> index b55045b..c30d613 100644
> --- a/kernel/kexec.c
> +++ b/kernel/kexec.c
> @@ -945,7 +945,7 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
>  	int result;
>  
>  	/* We only trust the superuser with rebooting the system. */
> -	if (!capable(CAP_SYS_BOOT))
> +	if (!capable(CAP_SYS_BOOT) || !capable(CAP_SYS_MODULE))
>  		return -EPERM;
>  
>  	/*

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  parent reply	other threads:[~2011-01-06  8:47 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-06  8:25 [Patch] kexec_load: check CAP_SYS_MODULE Amerigo Wang
2011-01-06  8:25 ` Amerigo Wang
2011-01-06  8:27 ` Cong Wang
2011-01-06  8:27   ` Cong Wang
2011-01-06  8:47 ` Eric W. Biederman [this message]
2011-01-06  8:47   ` Eric W. Biederman
2011-01-06 19:02   ` Eric Paris
2011-01-06 19:02     ` Eric Paris
2011-01-07 20:10     ` Eric W. Biederman
2011-01-07 20:10       ` Eric W. Biederman
2011-01-07 20:32       ` Eric Paris
2011-01-07 20:32         ` Eric Paris
2011-01-07 21:02         ` Eric W. Biederman
2011-01-07 21:02           ` Eric W. Biederman
2011-01-08  0:39           ` Eric Paris
2011-01-08  0:39             ` Eric Paris
2011-01-09  2:09             ` Eric W. Biederman
2011-01-09  2:09               ` Eric W. Biederman
2011-01-11 11:26               ` Cong Wang
2011-01-11 11:26                 ` Cong Wang
2011-01-14 19:47               ` Eric Paris
2011-01-14 19:47                 ` Eric Paris

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