On Wed, Apr 17, 2019 at 12:32 AM Alexandre Ghiti <alex@xxxxxxxx> wrote: > > mmap base address must be computed wrt stack top address, using TASK_SIZE > is wrong since STACK_TOP and TASK_SIZE are not equivalent. > > Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> -Kees > --- > arch/mips/mm/mmap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c > index 3ff82c6f7e24..ffbe69f3a7d9 100644 > --- a/arch/mips/mm/mmap.c > +++ b/arch/mips/mm/mmap.c > @@ -22,7 +22,7 @@ EXPORT_SYMBOL(shm_align_mask); > > /* gap between mmap and stack */ > #define MIN_GAP (128*1024*1024UL) > -#define MAX_GAP ((TASK_SIZE)/6*5) > +#define MAX_GAP ((STACK_TOP)/6*5) > #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) > > static int mmap_is_legacy(struct rlimit *rlim_stack) > @@ -54,7 +54,7 @@ static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack) > else if (gap > MAX_GAP) > gap = MAX_GAP; > > - return PAGE_ALIGN(TASK_SIZE - gap - rnd); > + return PAGE_ALIGN(STACK_TOP - gap - rnd); > } > > #define COLOUR_ALIGN(addr, pgoff) \ > -- > 2.20.1 > -- Kees Cook
