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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com,
	julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net,
	mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com,
	valentin.schneider@arm.com, brgerst@gmail.com, luto@kernel.org,
	bp@alien8.de, dvlasenk@redhat.com, linux-kernel@vger.kernel.org,
	dvyukov@google.com, rostedt@goodmis.org
Subject: Re: [PATCH 00/25] objtool: UACCESS validation v4
Date: Mon, 18 Mar 2019 18:57:07 -0500	[thread overview]
Message-ID: <20190318235707.wdaldl2354fxmbab@treble> (raw)
In-Reply-To: <20190318153840.906404905@infradead.org>

On Mon, Mar 18, 2019 at 04:38:40PM +0100, Peter Zijlstra wrote:
> Teach objtool to validate the UACCESS (SMAP, PAN) rules which are currently
> unenforced and (therefore obviously) violated.
> 
> UACCESS sections should be small; we want to limit the amount of code that can
> touch userspace. Furthermore, UACCESS state isn't scheduled, this means that
> anything that directly calls into the scheduler will result in random code
> running with UACCESS enabled and possibly getting back into the UACCESS region
> with UACCESS disabled and causing faults.
> 
> Forbid any CALL/RET while UACCESS is enabled; but provide a few exceptions.
> 
> This builds x86_64-allmodconfig and lots of x86_64-randconfig clean.
> 
> Changes since -v3:
> 
>  - removed a bunch of functions from the UACCESS-safe list
>    due to the removal of CONFIG_KASAN_EXTRA=y.
> 
>  - hopefully addressed all the feedback from Josh
> 
>  - realized objtool doesn't cover x86_32
> 
>  - some added additional annotations/fixes: kcov, signal
> 
>  - retains the DF check for now, Linus, do you (still) think it is worth doing
>    that DF check?

I'm still not crazy about the DF thing, but otherwise everything looks
great.

For the objtool bits:

Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>

-- 
Josh

  parent reply	other threads:[~2019-03-18 23:57 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-18 15:38 [PATCH 00/25] objtool: UACCESS validation v4 Peter Zijlstra
2019-03-18 15:38 ` [PATCH 01/25] x86: Make SMAP 64-bit only Peter Zijlstra
2019-03-18 16:58   ` Linus Torvalds
2019-03-18 17:36     ` Peter Zijlstra
2019-03-18 17:51       ` Peter Zijlstra
2019-03-18 18:10         ` Linus Torvalds
2019-03-21 17:12           ` hpa
2019-03-21 17:25           ` Denys Vlasenko
2019-03-21 18:18             ` hpa
2019-03-21 21:03               ` Peter Zijlstra
2019-03-21 18:21             ` Linus Torvalds
2019-03-19 11:16   ` [PATCH 01/25] sched/x86: Save [ER]FLAGS on context switch Peter Zijlstra
2019-03-18 15:38 ` [PATCH 02/25] tracing: Improve "if" macro code generation Peter Zijlstra
2019-03-18 17:41   ` Steven Rostedt
2019-03-18 23:37   ` Josh Poimboeuf
2019-03-19 10:11     ` Peter Zijlstra
2019-03-20 11:18   ` David Laight
2019-03-20 17:26     ` Linus Torvalds
2019-03-20 17:37       ` David Laight
2019-03-20 17:38         ` Linus Torvalds
2019-03-20 18:18       ` Steven Rostedt
2019-05-09 13:00       ` Steven Rostedt
2019-05-09 16:51         ` Linus Torvalds
2019-05-09 18:29           ` Steven Rostedt
2019-05-09 18:45             ` Josh Poimboeuf
2019-05-09 18:47               ` Josh Poimboeuf
2019-05-09 18:48                 ` Randy Dunlap
2019-05-09 18:57                   ` Josh Poimboeuf
2019-05-09 19:06               ` Steven Rostedt
2019-05-09 19:28                 ` Steven Rostedt
2019-05-09 19:44                   ` Linus Torvalds
2019-03-18 15:38 ` [PATCH 03/25] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-03-18 15:38 ` [PATCH 04/25] i915,uaccess: Fix redundant CLAC Peter Zijlstra
2019-03-18 15:38 ` [PATCH 05/25] x86/uaccess: Move copy_user_handle_tail into asm Peter Zijlstra
2019-03-18 15:38 ` [PATCH 06/25] x86/uaccess: Fix up the fixup Peter Zijlstra
2019-03-18 15:38 ` [PATCH 07/25] x86/nospec,objtool: Introduce ANNOTATE_IGNORE_ALTERNATIVE Peter Zijlstra
2019-03-18 15:38 ` [PATCH 08/25] x86/uaccess,xen: Suppress SMAP warnings Peter Zijlstra
2019-03-18 15:38 ` [PATCH 09/25] x86/uaccess: Always inline user_access_begin() Peter Zijlstra
2019-03-18 15:38 ` [PATCH 10/25] x86/uaccess,signal: Fix AC=1 bloat Peter Zijlstra
2019-03-18 15:38 ` [PATCH 11/25] x86/uaccess: Introduce user_access_{save,restore}() Peter Zijlstra
2019-03-18 15:38 ` [PATCH 12/25] x86/smap: Ditch __stringify() Peter Zijlstra
2019-03-18 15:38 ` [PATCH 13/25] x86/uaccess,kasan: Fix KASAN vs SMAP Peter Zijlstra
2019-03-18 15:38 ` [PATCH 14/25] x86/uaccess,ubsan: Fix UBSAN " Peter Zijlstra
2019-03-18 15:38 ` [PATCH 15/25] x86/uaccess,ftrace: Fix ftrace_likely_update() " Peter Zijlstra
2019-03-18 15:38 ` [PATCH 16/25] x86/uaccess,kcov: Disable stack protector Peter Zijlstra
2019-03-18 15:38 ` [PATCH 17/25] objtool: Set insn->func for alternatives Peter Zijlstra
2019-03-18 15:38 ` [PATCH 18/25] objtool: Handle function aliases Peter Zijlstra
2019-03-18 15:38 ` [PATCH 19/25] objtool: Rewrite add_ignores() Peter Zijlstra
2019-03-18 15:39 ` [PATCH 20/25] objtool: Add --backtrace support Peter Zijlstra
2019-03-18 15:39 ` [PATCH 21/25] objtool: Rewrite alt->skip_orig Peter Zijlstra
2019-03-18 15:39 ` [PATCH 22/25] objtool: Fix sibling call detection Peter Zijlstra
2019-03-18 15:39 ` [PATCH 23/25] objtool: Add UACCESS validation Peter Zijlstra
2019-03-18 23:51   ` Josh Poimboeuf
2019-05-07 11:52   ` Peter Zijlstra
2019-03-18 15:39 ` [PATCH 24/25] objtool: uaccess PUSHF/POPF support Peter Zijlstra
2019-03-18 15:39 ` [PATCH 25/25] objtool: Add Direction Flag validation Peter Zijlstra
2019-03-18 23:57 ` Josh Poimboeuf [this message]
2019-03-19 11:20   ` [PATCH 00/25] objtool: UACCESS validation v4 Peter Zijlstra
2019-03-19 11:17 ` [PATCH 26/25] sched/x86_64: Don't save flags on context switch Peter Zijlstra

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