[kernel-hardening] [PATCH v3 0/7] char/random: Simplify random address requests

From: Jason Cooper <jason@lakedaemon.net>
To: Kees Cook <keescook@chromium.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	"Roberts, William C" <william.c.roberts@intel.com>,
	Yann Droneaud <ydroneaud@opteya.com>
Cc: Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	kernel-hardening <kernel-hardening@lists.openwall.com>,
	Russell King - ARM Linux <linux@arm.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	Theodore Ts'o <tytso@mit.edu>, Arnd Bergmann <arnd@arndb.de>,
	gregkh@linuxfoundation.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Ralf Baechle <ralf@linux-mips.org>,
	benh@kernel.crashing.org, paulus@samba.org,
	"David S. Miller" <davem@davemloft.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org, viro@zeniv.linux.org.uk,
	Nick Kralevich <nnk@google.com>,
	Jeffrey Vander Stoep <jeffv@google.com>,
	Daniel Cashman <dcashman@android.com>,
	Jason Cooper <jason@lakedaemon.net>
Subject: [kernel-hardening] [PATCH v3 0/7] char/random: Simplify random address requests
Date: Wed,  3 Aug 2016 23:39:06 +0000	[thread overview]
Message-ID: <20160803233913.32511-1-jason@lakedaemon.net> (raw)
In-Reply-To: <20160728204730.27453-1-jason@lakedaemon.net>

Two previous attempts have been made to rework this API.  The first can be
found at:

  https://lkml.kernel.org/r/cover.1390770607.git.ydroneaud@opteya.com

The second at:

  https://lkml.kernel.org/r/1469471141-25669-1-git-send-email-william.c.roberts@intel.com

Previous versions of this series can been seen at:

RFC:  https://lkml.kernel.org/r/20160726030201.6775-1-jason@lakedaemon.net
 v1:  https://lkml.kernel.org/r/20160728204730.27453-1-jason@lakedaemon.net
 v2:  https://lkml.kernel.org/r/20160730154244.403-1-jason@lakedaemon.net

In addition to incorporating ideas from these two previous efforts, this series
adds several desirable features.  First, we take the range as an argument
directly, which removes math both before the call and inside the function.
Second, we return the start address on error.  All callers fell back to the
start address on error, so we remove the need to check for errors.  Third, we
cap range to prevent overflow.  Last, we use kerneldoc to describe the new
function.

If possible, I'd like to request Acks from the various subsystems so that we
can merge this as one bisectable branch.

Changes from v2:
 - s/randomize_addr/randomize_page/ (Kees Cook)
 - PAGE_ALIGN(start) if it wasn't (Kees Cook, Michael Ellerman)

Changes from v1:
 - Explicitly mention page_aligned start assumption (Yann Droneaud)
 - pick random pages vice random addresses (Yann Droneaud)
 - catch range=0 last
 - Add Ack for arm64 (Will Deacon)

Jason Cooper (7):
  random: Simplify API for random address requests
  x86: Use simpler API for random address requests
  ARM: Use simpler API for random address requests
  arm64: Use simpler API for random address requests
  tile: Use simpler API for random address requests
  unicore32: Use simpler API for random address requests
  random: Remove unused randomize_range()

 arch/arm/kernel/process.c       |  3 +--
 arch/arm64/kernel/process.c     |  8 ++------
 arch/tile/mm/mmap.c             |  3 +--
 arch/unicore32/kernel/process.c |  3 +--
 arch/x86/kernel/process.c       |  3 +--
 arch/x86/kernel/sys_x86_64.c    |  5 +----
 drivers/char/random.c           | 36 +++++++++++++++++++++++++-----------
 include/linux/random.h          |  2 +-
 8 files changed, 33 insertions(+), 30 deletions(-)

-- 
2.9.2