From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
Kees Cook <keescook@chromium.org>,
Brian Gerst <brgerst@gmail.com>
Subject: Re: [PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS and !pagefault_disabled()
Date: Wed, 25 May 2016 17:33:01 +0200 [thread overview]
Message-ID: <20160525153301.GE4420@pd.tnic> (raw)
In-Reply-To: <f766e3c623fd9cf76568741e28e28d0de7d912ce.1464129798.git.luto@kernel.org>
On Tue, May 24, 2016 at 03:48:44PM -0700, Andy Lutomirski wrote:
> + if (unlikely(!is_user_ds && !pagefault_disabled())) {
> + if (extra < TASK_SIZE_MAX) {
> + /*
> + * Accessing user address under KERNEL_DS. This is a
> + * bug and should be fixed, but OOPSing is not helpful
> + * for exploit mitigation.
> + */
> + WARN_ONCE(1, "BUG: uaccess fault at 0x%lx with KERNEL_DS\n",
WARN and BUG?
Also, let's have this string and the one below differ for finding out
where we are during debugging.
> + extra);
> + } else {
> + /*
> + * If a bug that allows user-controlled KERNEL_DS
> + * access exists, this will prevent it from being used
> + * to trivially bypass kASLR.
> + */
> + pr_crit("BUG: uaccess fault at 0x%lx with KERNEL_DS\n",
> + extra);
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
next prev parent reply other threads:[~2016-05-25 15:33 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-24 22:48 [PATCH 0/7] x86: uaccess hardening, easy part Andy Lutomirski
2016-05-24 22:48 ` [PATCH 1/7] x86/xen: Simplify set_aliased_prot Andy Lutomirski
2016-05-25 9:38 ` Andrew Cooper
2016-05-25 9:50 ` [Xen-devel] " David Vrabel
2016-06-10 22:12 ` Andy Lutomirski
2016-06-11 9:29 ` Ingo Molnar
2016-06-11 9:34 ` [tip:x86/asm] x86/xen: Simplify set_aliased_prot() tip-bot for Andy Lutomirski
2016-05-24 22:48 ` [PATCH 2/7] x86/extable: Pass error_code and an extra unsigned long to exhandlers Andy Lutomirski
2016-05-24 22:48 ` [PATCH 3/7] x86/uaccess: Give uaccess faults their own handler Andy Lutomirski
2016-05-24 22:48 ` [PATCH 4/7] x86/dumpstack: If addr_limit is non-default, display it Andy Lutomirski
2016-05-25 11:32 ` Borislav Petkov
2016-05-29 16:44 ` Andy Lutomirski
2016-05-25 11:39 ` Borislav Petkov
2016-05-29 16:47 ` Andy Lutomirski
2016-05-29 18:42 ` Boris Petkov
2016-05-29 19:08 ` Andy Lutomirski
2016-05-30 7:40 ` Borislav Petkov
2016-05-24 22:48 ` [PATCH 5/7] x86/uaccess: Warn on uaccess faults other than #PF Andy Lutomirski
2016-05-25 9:49 ` Borislav Petkov
2016-05-29 16:42 ` Andy Lutomirski
2016-05-24 22:48 ` [PATCH 6/7] x86/uaccess: Don't fix up USER_DS uaccess faults to kernel addresses Andy Lutomirski
2016-05-24 22:48 ` [PATCH 7/7] x86/uaccess: OOPS or warn on a fault with KERNEL_DS and !pagefault_disabled() Andy Lutomirski
2016-05-25 15:33 ` Borislav Petkov [this message]
2016-05-29 16:52 ` Andy Lutomirski
2016-05-25 3:55 ` [PATCH 0/7] x86: uaccess hardening, easy part Brian Gerst
2016-05-25 17:19 ` Kees Cook
2016-05-25 17:31 ` Kees Cook
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