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From: Andy Lutomirski <luto@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Denys Vlasenko <dvlasenk@redhat.com>,
	Brian Gerst <brgerst@gmail.com>,
	Julien Thierry <julien.thierry@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Will Deacon <will.deacon@arm.com>,
	valentin.schneider@arm.com, Ingo Molnar <mingo@redhat.com>,
	James Morse <james.morse@arm.com>,
	Andrew Lutomirski <luto@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	"linux-alpha@vger.kernel.org"
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC][PATCH] objtool: STAC/CLAC validation
Date: Fri, 22 Feb 2019 16:34:34 -0800	[thread overview]
Message-ID: <CALCETrVw18nHQGPqg_OF=pD7NePafYQ_c1MhfSm_OCQ-O3xzhQ@mail.gmail.com> (raw)
In-Reply-To: <20190222222635.GK14054@worktop.programming.kicks-ass.net>

[-- Attachment #1: Type: text/plain, Size: 689 bytes --]

[mailing lists removed because this is a potentially large source of exploits]

On Fri, Feb 22, 2019 at 2:26 PM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Fri, Feb 22, 2019 at 07:10:34PM +0100, Thomas Gleixner wrote:
>
> > But correct :)
>
> > I agree, that a function which is doing the actual copy should be callable,
> > but random other functions? NO!
>
> So find the below patch -- which spotted fail in ptrace.c
>

Um, wait a moment.  You didn't find an oddity in ptrace.c.  You found
a giant freaking error in uaccess.h.

Am I missing something?  How are there not zillions of instances of
this that your patch ought to catch?  Or is genregs_get() really the
only example?

[-- Attachment #2: uaccess.patch --]
[-- Type: text/x-patch, Size: 568 bytes --]

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 780f2b42c8ef..df0571a07b55 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -431,8 +431,10 @@ do {									\
 ({								\
 	__label__ __pu_label;					\
 	int __pu_err = -EFAULT;					\
+	__typeof__(*(ptr)) __pu_val;				\
+	__pu_val = x;						\
 	__uaccess_begin();					\
-	__put_user_size((x), (ptr), (size), __pu_label);	\
+	__put_user_size(__pu_val, (ptr), (size), __pu_label);	\
 	__pu_err = 0;						\
 __pu_label:							\
 	__uaccess_end();					\

[-- Attachment #3: Type: text/plain, Size: 176 bytes --]

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  parent reply	other threads:[~2019-02-23  0:35 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-15 13:58 [PATCH v3 0/4] uaccess: Add unsafe accessors for arm64 Julien Thierry
2019-01-15 13:58 ` [PATCH v3 1/4] arm64: uaccess: Cleanup get/put_user() Julien Thierry
2019-01-15 13:58 ` [PATCH v3 2/4] arm64: uaccess: Implement unsafe accessors Julien Thierry
2019-01-15 13:58 ` [PATCH v3 3/4] uaccess: Check no rescheduling function is called in unsafe region Julien Thierry
2019-01-30 16:58   ` Valentin Schneider
2019-02-04 13:27     ` Julien Thierry
2019-02-11 13:45   ` Ingo Molnar
2019-02-11 13:51     ` Peter Zijlstra
2019-02-12  9:15       ` Julien Thierry
2019-02-13  8:21         ` Ingo Molnar
2019-02-13 10:35         ` Peter Zijlstra
2019-02-13 10:50           ` Julien Thierry
2019-02-13 13:17             ` Peter Zijlstra
2019-02-13 13:20               ` Peter Zijlstra
2019-02-13 14:00               ` Will Deacon
2019-02-13 14:07                 ` Julien Thierry
2019-02-13 14:17                 ` Peter Zijlstra
2019-02-13 14:24                   ` Julien Thierry
2019-02-13 14:40                     ` Peter Zijlstra
2019-02-13 15:08                       ` Peter Zijlstra
2019-02-13 14:25                 ` Peter Zijlstra
2019-02-13 14:39                   ` Julien Thierry
2019-02-13 14:41                     ` Peter Zijlstra
2019-02-13 15:45                       ` Peter Zijlstra
2019-02-13 18:54                         ` Peter Zijlstra
     [not found]                         ` <D61C430D-4321-4114-AB85-671A3C7B8EAE@amacapital.net>
2019-02-13 22:21                           ` Peter Zijlstra
2019-02-13 22:49                             ` Andy Lutomirski
2019-02-14 10:14                               ` [PATCH] sched/x86: Save [ER]FLAGS on context switch Peter Zijlstra
2019-02-14 16:18                                 ` Brian Gerst
2019-02-14 19:34                                   ` Peter Zijlstra
2019-02-15 14:34                                     ` Brian Gerst
2019-02-15 17:18                                     ` Linus Torvalds
2019-02-15 17:40                                       ` Peter Zijlstra
2019-02-15 18:28                                         ` Andy Lutomirski
2019-02-15 23:34                                         ` Peter Zijlstra
2019-02-16  0:21                                           ` Linus Torvalds
2019-02-16 10:32                                             ` Peter Zijlstra
2019-02-16  4:06                                 ` hpa
2019-02-16 10:30                                   ` Peter Zijlstra
2019-02-18 22:30                                     ` H. Peter Anvin
2019-02-19  0:24                                       ` Linus Torvalds
2019-02-19  2:20                                         ` Andy Lutomirski
2019-02-19  2:46                                           ` H. Peter Anvin
2019-02-19  9:07                                             ` Julien Thierry
2019-02-19  8:53                                         ` Julien Thierry
2019-02-19  9:15                                         ` Peter Zijlstra
2019-02-19  9:19                                           ` Peter Zijlstra
2019-02-19  9:04                                       ` Peter Zijlstra
2019-02-19  9:21                                         ` hpa
2019-02-19  9:44                                         ` Peter Zijlstra
2019-02-19 11:38                                           ` Thomas Gleixner
2019-02-19 11:58                                             ` Peter Zijlstra
2019-02-19 12:48                                         ` Will Deacon
2019-02-20 22:55                                           ` H. Peter Anvin
2019-02-21 12:06                                             ` Julien Thierry
2019-02-21 21:35                                               ` Thomas Gleixner
2019-02-21 22:08                                                 ` Linus Torvalds
2019-02-22 12:58                                                   ` Peter Zijlstra
2019-02-22 18:10                                                   ` Thomas Gleixner
2019-02-22 22:26                                                     ` [RFC][PATCH] objtool: STAC/CLAC validation Peter Zijlstra
2019-02-22 23:34                                                       ` Linus Torvalds
2019-02-23  8:43                                                         ` Peter Zijlstra
2019-02-22 23:39                                                       ` hpa
2019-02-23  8:39                                                         ` Peter Zijlstra
2019-02-25  8:47                                                           ` hpa
2019-02-25 13:21                                                             ` Peter Zijlstra
2019-03-01 15:07                                                               ` Peter Zijlstra
2019-02-25  8:49                                                           ` hpa
2019-02-22 23:55                                                       ` Andy Lutomirski
2019-02-23  8:37                                                         ` Peter Zijlstra
2019-02-23 10:52                                                           ` Peter Zijlstra
2019-02-25 10:51                                                         ` Peter Zijlstra
2019-02-25 11:53                                                           ` Peter Zijlstra
2019-02-25 15:36                                                             ` Andy Lutomirski
2019-02-23  0:34                                                       ` Andy Lutomirski [this message]
2019-02-23  1:12                                                         ` Linus Torvalds
2019-02-23  1:16                                                           ` Andy Lutomirski
2019-02-23  1:33                                                             ` Linus Torvalds
2019-02-23  1:40                                                             ` Linus Torvalds
2019-02-25  8:33                                                       ` Julien Thierry
2019-02-25 11:55                                                         ` Peter Zijlstra
2019-02-21 12:46                                             ` [PATCH] sched/x86: Save [ER]FLAGS on context switch Will Deacon
2019-02-21 22:06                                               ` Andy Lutomirski
2019-02-18  9:03                                 ` [PATCH v2] " Peter Zijlstra
2019-02-13 23:19                         ` [PATCH v3 3/4] uaccess: Check no rescheduling function is called in unsafe region Linus Torvalds
2019-01-15 13:58 ` [PATCH v3 4/4] arm64: uaccess: Implement user_access_region_active Julien Thierry
2019-01-25 14:27 ` [PATCH v3 0/4] uaccess: Add unsafe accessors for arm64 Catalin Marinas
2019-01-30 16:17 ` Julien Thierry

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