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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,
	"Hector Marco-Gisbert" <hecmargi@upv.es>,
	"Ismael Ripoll" <iripoll@upv.es>,
	"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>,
	"Min-Hua Chen" <orca.chen@gmail.com>,
	"Dan McGee" <dpmcgee@gmail.com>,
	"Yann Droneaud" <ydroneaud@opteya.com>,
	"Paul Burton" <paul.burton@imgtec.com>,
	"Alex Smith" <alex@alex-smith.me.uk>,
	"Markos Chandras" <markos.chandras@imgtec.com>,
	"Vineeth Vijayan" <vvijayan@mvista.com>,
	"Jeff Bailey" <jeffbailey@google.com>,
	"Michael Holzheu" <holzheu@linux.vnet.ibm.com>,
	"Ben Hutchings" <ben@decadent.org.uk>,
	"Behan Webster" <behanw@converseincode.com>,
	"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 v3 04/10] mips: extract logic for mmap_rnd()
Date: Tue,  3 Mar 2015 18:10:19 -0800	[thread overview]
Message-ID: <1425435025-30284-5-git-send-email-keescook@chromium.org> (raw)
In-Reply-To: <1425435025-30284-1-git-send-email-keescook@chromium.org>

In preparation for splitting out ET_DYN ASLR, extract the mmap ASLR
selection into a separate function.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/mips/mm/mmap.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index f1baadd56e82..673a5cfe082f 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -142,18 +142,26 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 			addr0, len, pgoff, flags, DOWN);
 }
 
+static unsigned long mmap_rnd(void)
+{
+	unsigned long rnd;
+
+	rnd = (unsigned long)get_random_int();
+	rnd <<= PAGE_SHIFT;
+	if (TASK_IS_32BIT_ADDR)
+		random_factor &= 0xfffffful;
+	else
+		random_factor &= 0xffffffful;
+
+	return rnd;
+}
+
 void arch_pick_mmap_layout(struct mm_struct *mm)
 {
 	unsigned long random_factor = 0UL;
 
-	if (current->flags & PF_RANDOMIZE) {
-		random_factor = get_random_int();
-		random_factor = random_factor << PAGE_SHIFT;
-		if (TASK_IS_32BIT_ADDR)
-			random_factor &= 0xfffffful;
-		else
-			random_factor &= 0xffffffful;
-	}
+	if (current->flags & PF_RANDOMIZE)
+		random_factor = mmap_rnd();
 
 	if (mmap_is_legacy()) {
 		mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;
-- 
1.9.1


  parent reply	other threads:[~2015-03-04  2:15 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-04  2:10 [PATCH v3 0/10] split ET_DYN ASLR from mmap ASLR Kees Cook
2015-03-04  2:10 ` [PATCH v3 01/10] arm: factor out mmap ASLR into mmap_rnd Kees Cook
2015-03-04  2:10 ` [PATCH v3 02/10] x86: standardize mmap_rnd() usage Kees Cook
2015-03-04  2:10 ` [PATCH v3 03/10] arm64: " Kees Cook
2015-03-04  2:10 ` Kees Cook [this message]
2015-03-04  2:10 ` [PATCH v3 05/10] powerpc: " Kees Cook
2015-03-04  2:10 ` [PATCH v3 06/10] s390: " Kees Cook
2015-03-04  2:10 ` [PATCH v3 07/10] mm: expose arch_mmap_rnd when available Kees Cook
2015-03-04  2:10 ` [PATCH v3 08/10] s390: redefine randomize_et_dyn for ELF_ET_DYN_BASE Kees Cook
2015-03-04  2:10 ` [PATCH v3 09/10] mm: split ET_DYN ASLR from mmap ASLR Kees Cook
2015-03-04  2:10 ` [PATCH v3 10/10] mm: fold arch_randomize_brk into ARCH_HAS_ELF_RANDOMIZE Kees Cook
2015-03-09 16:19 ` [PATCH v3 0/10] split ET_DYN ASLR from mmap ASLR Russell King - ARM Linux
2015-03-09 18:06   ` Kees Cook

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