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

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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

Inspired by Daniel Micay's linux-hardened tree.

Link: http://lkml.kernel.org/r/20170602152010.2064-7-riel@xxxxxxxxxx
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: Daniel Micay <danielmicay@xxxxxxxxx>
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/powerpc/mm/mmap.c |   28 +++++++++++++++++++---------
 1 file changed, 19 insertions(+), 9 deletions(-)

diff -puN arch/powerpc/mm/mmap.c~powerpcmmap-properly-account-for-stack-randomization-in-mmap_base arch/powerpc/mm/mmap.c
--- a/arch/powerpc/mm/mmap.c~powerpcmmap-properly-account-for-stack-randomization-in-mmap_base
+++ a/arch/powerpc/mm/mmap.c
@@ -34,16 +34,9 @@
 /*
  * Top of mmap area (just below the process stack).
  *
- * Leave at least a ~128 MB hole on 32bit applications.
- *
- * On 64bit applications we randomise the stack by 1GB so we need to
- * space our mmap start address by a further 1GB, otherwise there is a
- * chance the mmap area will end up closer to the stack than our ulimit
- * requires.
+ * Leave at least a ~128 MB hole.
  */
-#define MIN_GAP32 (128*1024*1024)
-#define MIN_GAP64 ((128 + 1024)*1024*1024UL)
-#define MIN_GAP ((is_32bit_task()) ? MIN_GAP32 : MIN_GAP64)
+#define MIN_GAP (128*1024*1024)
 #define MAX_GAP (TASK_SIZE/6*5)
 
 static inline int mmap_is_legacy(void)
@@ -71,9 +64,26 @@ unsigned long arch_mmap_rnd(void)
 	return rnd << PAGE_SHIFT;
 }
 
+static inline unsigned long stack_maxrandom_size(void)
+{
+	if (!(current->flags & PF_RANDOMIZE))
+		return 0;
+
+	/* 8MB for 32bit, 1GB for 64bit */
+	if (is_32bit_task())
+		return (1<<23);
+	else
+		return (1<<30);
+}
+
 static inline unsigned long mmap_base(unsigned long rnd)
 {
 	unsigned long gap = rlimit(RLIMIT_STACK);
+	unsigned long pad = stack_maxrandom_size();
+
+	/* Values close to RLIM_INFINITY can overflow. */
+	if (gap + pad > gap)
+		gap += pad;
 
 	if (gap < MIN_GAP)
 		gap = MIN_GAP;
_

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

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

--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel Archive]     [IETF Annouce]     [DCCP]     [Netdev]     [Networking]     [Security]     [Bugtraq]     [Yosemite]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux SCSI]

  Powered by Linux