[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <CAGXu5j+byHUn_rb9jOTZqMYrc4ngmDj=a3k8QRTYrZYNSjhCkw@mail.gmail.com>
Date: Tue, 20 Jun 2017 13:24:07 -0700
From: Kees Cook <keescook@...omium.org>
To: Thomas Garnier <thgarnie@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>,
"H . Peter Anvin" <hpa@...or.com>, Andy Lutomirski <luto@...nel.org>, Paolo Bonzini <pbonzini@...hat.com>,
Rik van Riel <riel@...hat.com>, Oleg Nesterov <oleg@...hat.com>, Josh Poimboeuf <jpoimboe@...hat.com>,
Petr Mladek <pmladek@...e.com>, Miroslav Benes <mbenes@...e.cz>, Al Viro <viro@...iv.linux.org.uk>,
Arnd Bergmann <arnd@...db.de>, Dave Hansen <dave.hansen@...el.com>,
David Howells <dhowells@...hat.com>, Russell King <linux@...linux.org.uk>,
Andy Lutomirski <luto@...capital.net>, Will Drewry <wad@...omium.org>,
Will Deacon <will.deacon@....com>, Catalin Marinas <catalin.marinas@....com>,
Mark Rutland <mark.rutland@....com>, Pratyush Anand <panand@...hat.com>,
Chris Metcalf <cmetcalf@...lanox.com>, "x86@...nel.org" <x86@...nel.org>,
LKML <linux-kernel@...r.kernel.org>, Linux API <linux-api@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>
Subject: Re: [PATCH v10 1/3] x86/syscalls: Check address limit on user-mode return
On Wed, Jun 14, 2017 at 6:12 PM, Thomas Garnier <thgarnie@...gle.com> wrote:
> Ensure the address limit is a user-mode segment before returning to
> user-mode. Otherwise a process can corrupt kernel-mode memory and elevate
> privileges [1].
>
> The set_fs function sets the TIF_SETFS flag to force a slow path on
> return. In the slow path, the address limit is checked to be USER_DS if
> needed.
>
> The addr_limit_user_check function is added as a cross-architecture
> function to check the address limit.
>
> [1] https://bugs.chromium.org/p/project-zero/issues/detail?id=990
>
> Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
Thanks for reworking this series!
The bad state correctly BUGs under the LKDTM test:
[ 21.171586] lkdtm: Performing direct entry CORRUPT_USER_DS
[ 21.172791] lkdtm: setting bad task size limit
[ 21.173742] ------------[ cut here ]------------
[ 21.174641] kernel BUG at ./include/linux/syscalls.h:220!
...
[ 21.193166] Call Trace:
[ 21.193617] ? trace_hardirqs_on_thunk+0x1a/0x1c
[ 21.194443] entry_SYSCALL64_slow_path+0x25/0x25
Tested-by: Kees Cook <keescook@...omium.org>
-Kees
--
Kees Cook
Pixel Security
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
