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From: Kees Cook <keescook@chromium.org>
To: akpm@linux-foundation.org
Cc: "Kees Cook" <keescook@chromium.org>,
	linux-kernel@vger.kernel.org,
	"Russell King" <linux@arm.linux.org.uk>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Will Deacon" <will.deacon@arm.com>,
	"Ralf Baechle" <ralf@linux-mips.org>,
	"Benjamin Herrenschmidt" <benh@kernel.crashing.org>,
	"Paul Mackerras" <paulus@samba.org>,
	"Michael Ellerman" <mpe@ellerman.id.au>,
	"Martin Schwidefsky" <schwidefsky@de.ibm.com>,
	"Heiko Carstens" <heiko.carstens@de.ibm.com>,
	linux390@de.ibm.com, x86@kernel.org,
	"Alexander Viro" <viro@zeniv.linux.org.uk>,
	"Oleg Nesterov" <oleg@redhat.com>,
	"Andy Lutomirski" <luto@amacapital.net>,
	"David A. Long" <dave.long@linaro.org>,
	"Andrey Ryabinin" <a.ryabinin@samsung.com>,
	"Arun Chandran" <achandran@mvista.com>,
	"Yann Droneaud" <ydroneaud@opteya.com>,
	"Min-Hua Chen" <orca.chen@gmail.com>,
	"Paul Burton" <paul.burton@imgtec.com>,
	"Alex Smith" <alex@alex-smith.me.uk>,
	"Markos Chandras" <markos.chandras@imgtec.com>,
	"Jeff Bailey" <jeffbailey@google.com>,
	"Vineeth Vijayan" <vvijayan@mvista.com>,
	"Michael Holzheu" <holzheu@linux.vnet.ibm.com>,
	"Ben Hutchings" <ben@decadent.org.uk>,
	"Hector Marco-Gisbert" <hecmargi@upv.es>,
	"Borislav Petkov" <bp@suse.de>, "Jan-Simon Möller" <dl9pf@gmx.de>,
	linux-arm-kernel@lists.infradead.org, linux-mips@linux-mips.org,
	linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
	linux-fsdevel@vger.kernel.org
Subject: [PATCH 1/5] arm: factor out mmap ASLR into mmap_rnd
Date: Mon,  2 Mar 2015 16:19:44 -0800	[thread overview]
Message-ID: <1425341988-1599-2-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1425341988-1599-1-git-send-email-keescook@chromium.org>

In preparation for exporting per-arch mmap randomization functions,
this moves the ASLR calculations for mmap on ARM into a separate routine.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/arm/mm/mmap.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index 5e85ed371364..0f8bc158f2c6 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -169,14 +169,21 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 	return addr;
 }
 
-void arch_pick_mmap_layout(struct mm_struct *mm)
+static unsigned long mmap_rnd(void)
 {
-	unsigned long random_factor = 0UL;
+	unsigned long rnd = 0UL;
 
 	/* 8 bits of randomness in 20 address space bits */
 	if ((current->flags & PF_RANDOMIZE) &&
 	    !(current->personality & ADDR_NO_RANDOMIZE))
-		random_factor = (get_random_int() % (1 << 8)) << PAGE_SHIFT;
+		rnd = (get_random_int() % (1 << 8)) << PAGE_SHIFT;
+
+	return rnd;
+}
+
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+	unsigned long random_factor = mmap_rnd();
 
 	if (mmap_is_legacy()) {
 		mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
-- 
1.9.1


  reply	other threads:[~2015-03-03  0:21 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-03  0:19 [PATCH v2 0/5] split ET_DYN ASLR from mmap ASLR Kees Cook
2015-03-03  0:19 ` Kees Cook [this message]
2015-03-09 14:48   ` [PATCH 1/5] arm: factor out mmap ASLR into mmap_rnd Russell King - ARM Linux
2015-03-03  0:19 ` [PATCH 2/5] mm: expose arch_mmap_rnd when available Kees Cook
2015-03-09 14:49   ` Russell King - ARM Linux
2015-03-03  0:19 ` [PATCH 3/5] mm: move randomize_et_dyn into ELF_ET_DYN_BASE Kees Cook
2015-03-03  0:19 ` [PATCH 4/5] mm: split ET_DYN ASLR from mmap ASLR Kees Cook
2015-03-04  4:16   ` Michael Ellerman
2015-03-04 21:13     ` Kees Cook
2015-03-04 23:56       ` Michael Ellerman
2015-03-09 15:13   ` Russell King - ARM Linux
2015-03-03  0:19 ` [PATCH 5/5] mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZE Kees Cook
2015-03-09 14:51   ` Russell King - ARM Linux
2015-03-03  7:31 ` [PATCH v2 0/5] split ET_DYN ASLR from mmap ASLR Ingo Molnar
2015-03-03 18:03   ` Kees Cook
2015-03-04  4:20     ` Ingo Molnar
2015-03-09 15:15 ` Russell King - ARM Linux
  -- strict thread matches above, loose matches on Subject: below --
2015-02-27  3:07 [PATCH " Kees Cook
2015-02-27  3:07 ` [PATCH 1/5] arm: factor out mmap ASLR into mmap_rnd Kees Cook

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