From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Subject: mm: untag user pointers in get_vaddr_frames This patch is a part of a series that extends kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. get_vaddr_frames uses provided user pointers for vma lookups, which can only by done with untagged pointers. Instead of locating and changing all callers of this function, perform untagging in it. Link: http://lkml.kernel.org/r/28f05e49c92b2a69c4703323d6c12208f3d881fe.1563904656.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Reviewed-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: Eric Auger <eric.auger@xxxxxxxxxx> Cc: Felix Kuehling <Felix.Kuehling@xxxxxxx> Cc: Jens Wiklander <jens.wiklander@xxxxxxxxxx> Cc: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/frame_vector.c | 2 ++ 1 file changed, 2 insertions(+) --- a/mm/frame_vector.c~mm-untag-user-pointers-in-get_vaddr_frames +++ a/mm/frame_vector.c @@ -46,6 +46,8 @@ int get_vaddr_frames(unsigned long start if (WARN_ON_ONCE(nr_frames > vec->nr_allocated)) nr_frames = vec->nr_allocated; + start = untagged_addr(start); + down_read(&mm->mmap_sem); locked = 1; vma = find_vma_intersection(mm, start, start + 1); _
