From c8deec7181212f170191c7ffbb01a16367682f5b Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 21 Mar 2018 16:45:53 +0100 Subject: [PATCH] drm: udl: Properly check framebuffer mmap offsets commit 3b82a4db8eaccce735dffd50b4d4e1578099b8e8 upstream. The memmap options sent to the udl framebuffer driver were not being checked for all sets of possible crazy values. Fix this up by properly bounding the allowed values. Reported-by: Eyal Itkin Cc: stable Signed-off-by: Greg Kroah-Hartman Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20180321154553.GA18454@kroah.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/udl/udl_fb.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c index b5b335c9b2bb..2ebdc6d5a76e 100644 --- a/drivers/gpu/drm/udl/udl_fb.c +++ b/drivers/gpu/drm/udl/udl_fb.c @@ -159,10 +159,15 @@ static int udl_fb_mmap(struct fb_info *info, struct vm_area_struct *vma) { unsigned long start = vma->vm_start; unsigned long size = vma->vm_end - vma->vm_start; - unsigned long offset = vma->vm_pgoff << PAGE_SHIFT; + unsigned long offset; unsigned long page, pos; - if (offset + size > info->fix.smem_len) + if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT)) + return -EINVAL; + + offset = vma->vm_pgoff << PAGE_SHIFT; + + if (offset > info->fix.smem_len || size > info->fix.smem_len - offset) return -EINVAL; pos = (unsigned long)info->fix.smem_start + offset; -- 2.20.1