From 631334908d120129678f68cdcca333565748fde7 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 [ Upstream commit 3b82a4db8eaccce735dffd50b4d4e1578099b8e8 ] 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: Sasha Levin --- 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 cd8d183dcfe56..ccb26652198b3 100644 --- a/drivers/gpu/drm/udl/udl_fb.c +++ b/drivers/gpu/drm/udl/udl_fb.c @@ -256,10 +256,15 @@ 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; -- 2.47.2