Messages in this thread | | | Subject | Re: [PATCH v6 11/14] mips: Adjust brk randomization offset to fit generic version | From | Sergei Shtylyov <> | Date | Thu, 8 Aug 2019 12:19:56 +0300 |
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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 <keescook@chromium.org> > Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> > Acked-by: Paul Burton <paul.burton@mips.com> > Reviewed-by: Kees Cook <keescook@chromium.org> > Reviewed-by: Luis Chamberlain <mcgrof@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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