Re: [PATCH REBASE v4 11/14] mips: Adjust brk randomization offset to fit generic version
From: Alexandre Ghiti <alex@ghiti.fr>
Date: 2019-07-25 06:22:16
Also in:
linux-arm-kernel, linux-fsdevel, linux-mm, linux-riscv, lkml
Subsystem:
mips, the rest · Maintainers:
Thomas Bogendoerfer, Linus Torvalds
On 7/24/19 7:58 AM, Alexandre Ghiti wrote:
quoted hunk ↗ jump to hunk
This commit simply bumps up to 32MB and 1GB the random offset of brk, compared to 8MB and 256MB, for 32bit and 64bit respectively. Suggested-by: Kees Cook <redacted> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> Reviewed-by: Kees Cook <redacted> --- arch/mips/mm/mmap.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c index a7e84b2e71d7..faa5aa615389 100644 --- a/arch/mips/mm/mmap.c +++ b/arch/mips/mm/mmap.c@@ -16,6 +16,7 @@ #include <linux/random.h> #include <linux/sched/signal.h> #include <linux/sched/mm.h> +#include <linux/sizes.h> unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */ EXPORT_SYMBOL(shm_align_mask);@@ -189,11 +190,11 @@ static inline unsigned long brk_rnd(void) unsigned long rnd = get_random_long(); rnd = rnd << PAGE_SHIFT; - /* 8MB for 32bit, 256MB for 64bit */ + /* 32MB for 32bit, 1GB for 64bit */ if (TASK_IS_32BIT_ADDR) - rnd = rnd & 0x7ffffful; + rnd = rnd & SZ_32M; else - rnd = rnd & 0xffffffful; + rnd = rnd & SZ_1G; return rnd; }
Hi Andrew, I have just noticed that this patch is wrong, do you want me to send another version of the entire series or is the following diff enough ? This mistake gets fixed anyway in patch 13/14 when it gets merged with the generic version. Sorry about that, Thanks, Alex
diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index a7e84b2e71d7..ff6ab87e9c56 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c@@ -16,6 +16,7 @@ #include <linux/random.h> #include <linux/sched/signal.h> #include <linux/sched/mm.h> +#include <linux/sizes.h> unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */ EXPORT_SYMBOL(shm_align_mask);
@@ -189,11 +190,11 @@ static inline unsigned long brk_rnd(void) unsigned long rnd = get_random_long(); rnd = rnd << PAGE_SHIFT; - /* 8MB for 32bit, 256MB for 64bit */ + /* 32MB for 32bit, 1GB for 64bit */ if (TASK_IS_32BIT_ADDR) - rnd = rnd & 0x7ffffful; + rnd = rnd & (SZ_32M - 1); else - rnd = rnd & 0xffffffful; + rnd = rnd & (SZ_1G - 1); return rnd; }