From: Alexandre Ghiti alex@ghiti.fr
[ Upstream commit 86e568e9c0525fc40e76d827212d5e9721cf7504 ]
mmap base address must be computed wrt stack top address, using TASK_SIZE is wrong since STACK_TOP and TASK_SIZE are not equivalent.
Link: http://lkml.kernel.org/r/20190730055113.23635-8-alex@ghiti.fr Signed-off-by: Alexandre Ghiti alex@ghiti.fr Acked-by: Kees Cook keescook@chromium.org Reviewed-by: Luis Chamberlain mcgrof@kernel.org Cc: Albert Ou aou@eecs.berkeley.edu Cc: Alexander Viro viro@zeniv.linux.org.uk Cc: Catalin Marinas catalin.marinas@arm.com Cc: Christoph Hellwig hch@infradead.org Cc: Christoph Hellwig hch@lst.de Cc: James Hogan jhogan@kernel.org Cc: Palmer Dabbelt palmer@sifive.com Cc: Paul Burton paul.burton@mips.com Cc: Ralf Baechle ralf@linux-mips.org Cc: Russell King linux@armlinux.org.uk Cc: Will Deacon will.deacon@arm.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 bff3d00bda5be..0b94b674aa91f 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); }
/*