Fix a few incorrectly checked [io_]remap_pfn_range() calls

Nico Golde reports a few straggling uses of [io_]remap_pfn_range() that
really should use the vm_iomap_memory() helper.  This trivially converts
two of them to the helper, and comments about why the third one really
needs to continue to use remap_pfn_range(), and adds the missing size
check.

Reported-by: Nico Golde <nico@ngolde.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 7314e613d5ff9f0934f7a0f74ed7973b903315d1)
[wt: vm_flags were absent in mainline, Ben removed them in 3.2, but
 I kept them to minimize changes and avoid any side effect]
Signed-off-by: Willy Tarreau <w@1wt.eu>

1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index e941367dd28f..e3804d3a1cbc 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -669,16 +669,30 @@ static int uio_mmap_physical(struct vm_area_struct *vma)
 {
 	struct uio_device *idev = vma->vm_private_data;
 	int mi = uio_find_mem_index(vma);
+	struct uio_mem *mem;
 	if (mi < 0)
 		return -EINVAL;
+	mem = idev->info->mem + mi;
+
+	if (vma->vm_end - vma->vm_start > mem->size)
+		return -EINVAL;
 
 	vma->vm_flags |= VM_IO | VM_RESERVED;
 
 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
+	/*
+	 * We cannot use the vm_iomap_memory() helper here,
+	 * because vma->vm_pgoff is the map index we looked
+	 * up above in uio_find_mem_index(), rather than an
+	 * actual page offset into the mmap.
+	 *
+	 * So we just do the physical mmap without a page
+	 * offset.
+	 */
 	return remap_pfn_range(vma,
 			       vma->vm_start,
-			       idev->info->mem[mi].addr >> PAGE_SHIFT,
+			       mem->addr >> PAGE_SHIFT,
 			       vma->vm_end - vma->vm_start,
 			       vma->vm_page_prot);
 }