* + arm-mm-support-arch_mmap_rnd_bits.patch added to -mm tree
@ 2015-11-25 0:40 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2015-11-25 0:40 UTC (permalink / raw)
To: dcashman, aarcange, benh, bp, catalin.marinas, corbet, dzickus,
ebiederm, hecmargi, hpa, jeffv, jpoimboe, keescook,
kirill.shutemov, linux, mgorman, mingo, n-horiguchi, nnk, ralf,
rientjes, salyzyn, tglx, will.deacon, xypron.glpk, mm-commits
The patch titled
Subject: arm: mm: support ARCH_MMAP_RND_BITS
has been added to the -mm tree. Its filename is
arm-mm-support-arch_mmap_rnd_bits.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm-mm-support-arch_mmap_rnd_bits.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm-mm-support-arch_mmap_rnd_bits.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Daniel Cashman <dcashman@google.com>
Subject: arm: mm: support ARCH_MMAP_RND_BITS
arm: arch_mmap_rnd() uses a hard-code value of 8 to generate the random
offset for the mmap base address. This value represents a compromise
between increased ASLR effectiveness and avoiding address-space
fragmentation. Replace it with a Kconfig option, which is sensibly
bounded, so that platform developers may choose where to place this
compromise. Keep 8 as the minimum acceptable value.
Signed-off-by: Daniel Cashman <dcashman@google.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Heinrich Schuchardt <xypron.glpk@gmx.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Jeff Vander Stoep <jeffv@google.com>
Cc: Nick Kralevich <nnk@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hector Marco-Gisbert <hecmargi@upv.es>
Cc: Borislav Petkov <bp@suse.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc; Heiko Carstens <heiko.carstens@de.ibm.com>
Cc; Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
arch/arm/Kconfig | 10 ++++++++++
arch/arm/mm/mmap.c | 3 +--
2 files changed, 11 insertions(+), 2 deletions(-)
diff -puN arch/arm/Kconfig~arm-mm-support-arch_mmap_rnd_bits arch/arm/Kconfig
--- a/arch/arm/Kconfig~arm-mm-support-arch_mmap_rnd_bits
+++ a/arch/arm/Kconfig
@@ -35,6 +35,7 @@ config ARM
select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32
select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32
+ select HAVE_ARCH_MMAP_RND_BITS
select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)
select HAVE_ARCH_TRACEHOOK
select HAVE_BPF_JIT
@@ -306,6 +307,15 @@ config MMU
Select if you want MMU-based virtualised addressing space
support by paged memory management. If unsure, say 'Y'.
+config ARCH_MMAP_RND_BITS_MIN
+ default 8
+
+config ARCH_MMAP_RND_BITS_MAX
+ default 14 if MMU && PAGE_OFFSET=0x40000000
+ default 15 if MMU && PAGE_OFFSET=0x80000000
+ default 16 if MMU
+ default 8
+
#
# The "ARM system type" choice list is ordered alphabetically by option
# text. Please add new entries in the option alphabetic order.
diff -puN arch/arm/mm/mmap.c~arm-mm-support-arch_mmap_rnd_bits arch/arm/mm/mmap.c
--- a/arch/arm/mm/mmap.c~arm-mm-support-arch_mmap_rnd_bits
+++ a/arch/arm/mm/mmap.c
@@ -173,8 +173,7 @@ unsigned long arch_mmap_rnd(void)
{
unsigned long rnd;
- /* 8 bits of randomness in 20 address space bits */
- rnd = (unsigned long)get_random_int() % (1 << 8);
+ rnd = (unsigned long)get_random_int() % (1 << mmap_rnd_bits);
return rnd << PAGE_SHIFT;
}
_
Patches currently in -mm which might be from dcashman@google.com are
mm-mmap-add-new-proc-tunable-for-mmap_base-aslr.patch
arm-mm-support-arch_mmap_rnd_bits.patch
arm64-mm-support-arch_mmap_rnd_bits.patch
x86-mm-support-arch_mmap_rnd_bits.patch
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2015-11-25 0:40 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-11-25 0:40 + arm-mm-support-arch_mmap_rnd_bits.patch added to -mm tree akpm
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.