Hello!

On 08.08.2019 9:17, Alexandre Ghiti wrote:

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 <keesc...@chromium.org>
Signed-off-by: Alexandre Ghiti <a...@ghiti.fr>
Acked-by: Paul Burton <paul.bur...@mips.com>
Reviewed-by: Kees Cook <keesc...@chromium.org>
Reviewed-by: Luis Chamberlain <mcg...@kernel.org>
---
  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..ff6ab87e9c56 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
[...]
@@ -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);

   Why not make these 'rnd &= SZ_* - 1', while at it anyways?

[...]

MBR, Sergei

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