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>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org.

1 files changed, 15 insertions, 2 deletions

diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index ba475632c5fa..0e808cf91d97 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -642,16 +642,29 @@ 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;
 
-        vma->vm_ops = &uio_physical_vm_ops;
+        if (vma->vm_end - vma->vm_start > mem->size)
+                return -EINVAL;
 
+        vma->vm_ops = &uio_physical_vm_ops;
         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);
 }