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From: Peter Zijlstra <peterz@infradead.org>
To: 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,
	jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de,
	dvlasenk@redhat.com
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org
Subject: [PATCH 0/6] objtool: UACCESS validation
Date: Mon, 25 Feb 2019 13:43:30 +0100	[thread overview]
Message-ID: <20190225124330.613028745@infradead.org> (raw)


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 an annotation to mark
(a very limited) set of functions as UACCESS-safe (eg. the planned:
unsafe_copy_{to,from}_user()).

---
 arch/x86/ia32/ia32_signal.c     |  29 ++++---
 arch/x86/include/asm/uaccess.h  |   4 +-
 include/linux/frame.h           |  49 ++++++++++-
 tools/objtool/Makefile          |   2 +-
 tools/objtool/arch.h            |   6 +-
 tools/objtool/arch/x86/decode.c |  22 ++++-
 tools/objtool/check.c           | 180 ++++++++++++++++++++++++++++++----------
 tools/objtool/check.h           |   3 +-
 tools/objtool/elf.h             |   1 +
 9 files changed, 234 insertions(+), 62 deletions(-)


             reply	other threads:[~2019-02-25 12:53 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-25 12:43 Peter Zijlstra [this message]
2019-02-25 12:43 ` [PATCH 1/6] x86/uaccess: Dont evaluate argument inside AC region Peter Zijlstra
2019-02-25 15:43   ` Andy Lutomirski
2019-02-25 16:02     ` Peter Zijlstra
2019-02-25 16:36     ` Borislav Petkov
2019-02-25 16:50       ` Andy Lutomirski
2019-02-25 19:09     ` Linus Torvalds
2019-02-25 19:18       ` Borislav Petkov
2019-02-25 18:10   ` [tip:x86/urgent] x86/uaccess: Don't leak the AC flag into __put_user() value evaluation tip-bot for Andy Lutomirski
2019-02-25 19:46   ` tip-bot for Andy Lutomirski
2019-02-25 12:43 ` [PATCH 2/6] x86/ia32: Fix ia32_restore_sigcontext AC leak Peter Zijlstra
2019-02-25 15:41   ` Andy Lutomirski
2019-02-25 16:10     ` Peter Zijlstra
2019-02-25 16:29       ` Andy Lutomirski
2019-02-25 16:37         ` Peter Zijlstra
2019-02-25 16:41           ` Peter Zijlstra
2019-02-25 16:49           ` Andy Lutomirski
2019-02-25 12:43 ` [PATCH 3/6] objtool: Set insn->func for alternatives Peter Zijlstra
2019-02-25 12:43 ` [PATCH 4/6] objtool: Replace STACK_FRAME_NON_STANDARD annotation Peter Zijlstra
2019-02-25 16:11   ` Josh Poimboeuf
2019-02-25 16:17     ` Peter Zijlstra
2019-02-25 16:23       ` Josh Poimboeuf
2019-02-27 12:20     ` Peter Zijlstra
2019-02-28  0:30       ` Andy Lutomirski
2019-02-25 12:43 ` [PATCH 5/6] objtool: Add UACCESS validation Peter Zijlstra
2019-02-25 15:53   ` Andy Lutomirski
2019-02-25 16:12     ` Peter Zijlstra
2019-02-25 17:15       ` Peter Zijlstra
2019-02-25 17:34         ` Linus Torvalds
2019-02-25 17:38         ` Josh Poimboeuf
2019-02-27 14:08   ` Peter Zijlstra
2019-02-27 14:17     ` Andrey Ryabinin
2019-02-27 14:26       ` Peter Zijlstra
2019-02-27 14:33         ` Peter Zijlstra
2019-02-27 15:40           ` Dmitry Vyukov
2019-02-27 17:28             ` Peter Zijlstra
2019-02-28  9:40               ` Peter Zijlstra
2019-02-28  9:59                 ` Dmitry Vyukov
2019-02-28 10:05                   ` Dmitry Vyukov
2019-02-28 10:52                     ` Peter Zijlstra
2019-02-27 16:18     ` Linus Torvalds
2019-02-27 17:30       ` Peter Zijlstra
2019-02-27 17:36         ` Linus Torvalds
2019-02-25 12:43 ` [PATCH 6/6] objtool: Add Direction Flag validation Peter Zijlstra

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