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From: Alexandre Ghiti <alex@ghiti.fr>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>,
	Christoph Hellwig <hch@lst.de>,
	Russell King <linux@armlinux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Ralf Baechle <ralf@linux-mips.org>,
	Paul Burton <paul.burton@mips.com>,
	James Hogan <jhogan@kernel.org>,
	Palmer Dabbelt <palmer@sifive.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
	linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, Alexandre Ghiti <alex@ghiti.fr>
Subject: [PATCH v5 07/14] arm: Use STACK_TOP when computing mmap base address
Date: Tue, 30 Jul 2019 01:51:06 -0400	[thread overview]
Message-ID: <20190730055113.23635-8-alex@ghiti.fr> (raw)
In-Reply-To: <20190730055113.23635-1-alex@ghiti.fr>

mmap base address must be computed wrt stack top address, using TASK_SIZE
is wrong since STACK_TOP and TASK_SIZE are not equivalent.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
---
 arch/arm/mm/mmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c
index bff3d00bda5b..0b94b674aa91 100644
--- a/arch/arm/mm/mmap.c
+++ b/arch/arm/mm/mmap.c
@@ -19,7 +19,7 @@
 
 /* gap between mmap and stack */
 #define MIN_GAP		(128*1024*1024UL)
-#define MAX_GAP		((TASK_SIZE)/6*5)
+#define MAX_GAP		((STACK_TOP)/6*5)
 #define STACK_RND_MASK	(0x7ff >> (PAGE_SHIFT - 12))
 
 static int mmap_is_legacy(struct rlimit *rlim_stack)
@@ -51,7 +51,7 @@ static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
 	else if (gap > MAX_GAP)
 		gap = MAX_GAP;
 
-	return PAGE_ALIGN(TASK_SIZE - gap - rnd);
+	return PAGE_ALIGN(STACK_TOP - gap - rnd);
 }
 
 /*
-- 
2.20.1


  parent reply	other threads:[~2019-07-30  5:59 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-30  5:50 [PATCH v5 00/14] Provide generic top-down mmap layout functions Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 01/14] mm, fs: Move randomize_stack_top from fs to mm Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 02/14] arm64: Make use of is_compat_task instead of hardcoding this test Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 03/14] arm64: Consider stack randomization for mmap base only when necessary Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 04/14] arm64, mm: Move generic mmap layout functions to mm Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 05/14] arm64, mm: Make randomization selected by generic topdown mmap layout Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 06/14] arm: Properly account for stack randomization and stack guard gap Alexandre Ghiti
2019-07-30  5:51 ` Alexandre Ghiti [this message]
2019-07-30  5:51 ` [PATCH v5 08/14] arm: Use generic mmap top-down layout and brk randomization Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 09/14] mips: Properly account for stack randomization and stack guard gap Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 10/14] mips: Use STACK_TOP when computing mmap base address Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 11/14] mips: Adjust brk randomization offset to fit generic version Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 12/14] mips: Replace arch specific way to determine 32bit task with " Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 13/14] mips: Use generic mmap top-down layout and brk randomization Alexandre Ghiti
2019-07-30  5:51 ` [PATCH v5 14/14] riscv: Make mmap allocation top-down by default Alexandre Ghiti
2019-07-31  6:05   ` Alex Ghiti
2019-07-31 17:33     ` Guenter Roeck
2019-07-31 22:40   ` Paul Walmsley

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