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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-21 16:45:53 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2018-03-22 07:59:01 +0100
commit3b82a4db8eaccce735dffd50b4d4e1578099b8e8 (patch)
treed3b7f0f528c93bad7f2ab77e18d19322e5a165a6
parentdrm: Reject getfb for multi-plane framebuffers (diff)
downloadlinux-3b82a4db8eaccce735dffd50b4d4e1578099b8e8.tar.xz
linux-3b82a4db8eaccce735dffd50b4d4e1578099b8e8.zip
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 <eyalit@checkpoint.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20180321154553.GA18454@kroah.com
-rw-r--r--drivers/gpu/drm/udl/udl_fb.c9
1 files 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;