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From: Thomas Garnier <thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
To: Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: "Martin Schwidefsky"
	<schwidefsky-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>,
	"Heiko Carstens"
	<heiko.carstens-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org>,
	"David Howells"
	<dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"Arnd Bergmann" <arnd-r2nGTMty4D4@public.gmane.org>,
	"Dave Hansen"
	<dave.hansen-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
	"Al Viro"
	<viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
	"Thomas Gleixner" <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
	"René Nyffenegger"
	<mail-gLCNRsNSrVdVZEhyV+6z5nIPMjoJpjVV@public.gmane.org>,
	"Andrew Morton"
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	"Paul E . McKenney"
	<paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
	"Ingo Molnar" <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	"Oleg Nesterov" <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"Pavel Tikhomirov"
	<ptikhomirov-5HdwGun5lf+gSpxsJD1C4w@public.gmane.org>,
	"Stephen Smalley" <sds-+05T5uksL2qpZYMLLGbcSA@public.gmane.org>,
	"Ingo Molnar" <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"H . Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	"Andy Lutomirski" <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	"Paolo Bonzini"
	<pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"Rik van Riel" <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH v5 1/4] syscalls: Restore address limit after a syscall
Date: Fri, 31 Mar 2017 08:34:14 -0700	[thread overview]
Message-ID: <CAJcbSZFv3CBSR--LP=A=Yrc3NmdAZb+eYbwLR4+3PFSVXdiAHQ@mail.gmail.com> (raw)
In-Reply-To: <CAGXu5jKbqOvb2TtfpXhjPQFxEShaBu=RbBQORtqhcF1bD3As6w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Thu, Mar 23, 2017 at 1:15 PM, Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> wrote:
> On Thu, Mar 23, 2017 at 10:25 AM, Thomas Garnier <thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> wrote:
>> This patch ensures a syscall does not return to user-mode with a kernel
>> address limit. If that happened, a process can corrupt kernel-mode
>> memory and elevate privileges.
>>
>> For example, it would mitigation this bug:
>>
>> - https://bugs.chromium.org/p/project-zero/issues/detail?id=990
>>
>> The CONFIG_ARCH_NO_SYSCALL_VERIFY_PRE_USERMODE_STATE option is also
>> added so each architecture can optimize this change.
>>
>> Signed-off-by: Thomas Garnier <thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
>
> Awesome. :) I've tested this on x86 and arm with the LKDTM patch I'll
> post in a moment.
>
> [   46.977823] lkdtm: Performing direct entry CORRUPT_USER_DS
> [   46.978966] lkdtm: setting bad task size limit
> [   46.980302] ------------[ cut here ]------------
> [   46.981219] kernel BUG at ./include/linux/syscalls.h:200!
>
> Tested-by: Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

Thanks Kees. Any additional feedback? Andy?

>
> (Also note, your Signed-off-by lines are missing in patches 2-4)
>
> --
> Kees Cook
> Pixel Security



-- 
Thomas

      parent reply	other threads:[~2017-03-31 15:34 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-23 17:25 [PATCH v5 1/4] syscalls: Restore address limit after a syscall Thomas Garnier
2017-03-23 17:25 ` [PATCH v5 2/4] x86/syscalls: Specific usage of verify_pre_usermode_state Thomas Garnier
2017-03-23 20:36   ` Thomas Garnier
2017-03-23 17:25 ` [PATCH v5 3/4] arm/syscalls: " Thomas Garnier
     [not found]   ` <20170323172515.27950-3-thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-03-23 20:38     ` Thomas Garnier
2017-03-23 17:25 ` [PATCH v5 4/4] arm64/syscalls: " Thomas Garnier
     [not found]   ` <20170323172515.27950-4-thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-03-23 20:37     ` Thomas Garnier
     [not found] ` <20170323172515.27950-1-thgarnie-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
2017-03-23 20:15   ` [PATCH v5 1/4] syscalls: Restore address limit after a syscall Kees Cook
     [not found]     ` <CAGXu5jKbqOvb2TtfpXhjPQFxEShaBu=RbBQORtqhcF1bD3As6w-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2017-03-31 15:34       ` Thomas Garnier [this message]

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