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> --- arch/arm/mm/mmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm/mm/mmap.c b/arch/arm/mm/mmap.c index bff3d00bda5b..0b94b674aa91 100644 --- a/arch/arm/mm/mmap.c +++ b/arch/arm/mm/mmap.c @@ -19,7 +19,7 @@ /* 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) @@ -51,7 +51,7 @@ 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); } /* -- 2.20.1
