[to-be-updated] x86-mmap-properly-account-for-stack-randomization-in-mmap_base.patch removed from -mm tree

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The patch titled
     Subject: x86/mmap: properly account for stack randomization in mmap_base
has been removed from the -mm tree.  Its filename was
     x86-mmap-properly-account-for-stack-randomization-in-mmap_base.patch

This patch was dropped because an updated version will be merged

------------------------------------------------------
From: Rik van Riel <riel@xxxxxxxxxx>
Subject: x86/mmap: properly account for stack randomization in mmap_base

When RLIMIT_STACK is, for example, 256MB, the current code results in a
gap between the top of the task and mmap_base of 256MB, failing to take
into account the amount by which the stack address was randomized.  In
other words, the stack gets less than RLIMIT_STACK space.

Ensure that the gap between the stack and mmap_base always takes stack
randomization into account.

Obtained from Daniel Micay's linux-hardened tree.

Link: http://lkml.kernel.org/r/20170602152010.2064-4-riel@xxxxxxxxxx
Signed-off-by: Daniel Micay <danielmicay@xxxxxxxxx>
Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>
Reported-by: Florian Weimer <fweimer@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Larry Woodman <lwoodman@xxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 arch/x86/mm/mmap.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff -puN arch/x86/mm/mmap.c~x86-mmap-properly-account-for-stack-randomization-in-mmap_base arch/x86/mm/mmap.c
--- a/arch/x86/mm/mmap.c~x86-mmap-properly-account-for-stack-randomization-in-mmap_base
+++ a/arch/x86/mm/mmap.c
@@ -95,13 +95,18 @@ unsigned long arch_mmap_rnd(void)
 static unsigned long mmap_base(unsigned long rnd, unsigned long task_size)
 {
 	unsigned long gap = rlimit(RLIMIT_STACK);
+	unsigned long pad = stack_maxrandom_size(task_size);
 	unsigned long gap_min, gap_max;
 
+	/* Values close to RLIM_INFINITY can overflow. */
+	if (gap + pad > gap)
+		gap += pad;
+
 	/*
 	 * Top of mmap area (just below the process stack).
 	 * Leave an at least ~128 MB hole with possible stack randomization.
 	 */
-	gap_min = SIZE_128M + stack_maxrandom_size(task_size);
+	gap_min = SIZE_128M;
 	gap_max = (task_size / 6) * 5;
 
 	if (gap < gap_min)
_

Patches currently in -mm which might be from riel@xxxxxxxxxx are

arm64-mmap-properly-account-for-stack-randomization-in-mmap_base.patch
arm64-move-compat_elf_et_dyn_base-lower-in-the-address-space.patch
powerpcmmap-properly-account-for-stack-randomization-in-mmap_base.patch
randomstackprotect-introduce-get_random_canary-function.patch
forkrandom-use-get_random_canary-to-set-tsk-stack_canary.patch
x86-ascii-armor-the-x86_64-boot-init-stack-canary.patch
arm64-ascii-armor-the-arm64-boot-init-stack-canary.patch
sh64-ascii-armor-the-sh64-boot-init-stack-canary.patch

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