From: Greg Kroah-Hartman Date: Wed, 21 Mar 2018 15:45:53 +0000 (+0100) Subject: drm: udl: Properly check framebuffer mmap offsets X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=3b82a4db8eaccce735dffd50b4d4e1578099b8e8;p=openwrt%2Fstaging%2Fblogic.git drm: udl: Properly check framebuffer mmap offsets 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 --- 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;