bochs: Fix bitmap offset calculation

32 bit truncation could let us access the wrong offset in the image.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/block/bochs.c b/block/bochs.c
index a922782c1d47f7e63c167b6bad654bd2d8d09153..826ec1203c9ed04fda15bb55ef7274dd2ba2eba7 100644 (file)
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -186,8 +186,9 @@ static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
        return -1; /* not allocated */
     }
 
-    bitmap_offset = s->data_offset + (512 * s->catalog_bitmap[extent_index] *
-       (s->extent_blocks + s->bitmap_blocks));
+    bitmap_offset = s->data_offset +
+        (512 * (uint64_t) s->catalog_bitmap[extent_index] *
+        (s->extent_blocks + s->bitmap_blocks));
 
     /* read in bitmap for current extent */
     if (bdrv_pread(bs->file, bitmap_offset + (extent_offset / 8),