4.4-stable review patch. If anyone has any objections, please let me know.
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From: Greg Kroah-Hartman gregkh@linuxfoundation.org
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 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.c... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpu/drm/udl/udl_fb.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
--- 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 *i { 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;