On 4/18/19 1:31 AM, Kees Cook wrote:
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>
Thanks !
-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
