Commit 224eaa8a authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman

drm: udl: Properly check framebuffer mmap offsets

commit 3b82a4db 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: default avatarEyal Itkin <eyalit@checkpoint.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180321154553.GA18454@kroah.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 20b74f2b
......@@ -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;
......
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