From: Kevin Wolf <kwolf@redhat.com>
Date: Wed, 26 Mar 2014 13:05:35 +0100
Subject: [PATCH] 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>
(cherry picked from commit a9ba36a45dfac645a810c31ce15ab393b69d820a)
---
 block/bochs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/block/bochs.c b/block/bochs.c
index 10fbd39..6749a61 100644
--- a/block/bochs.c
+++ b/block/bochs.c
@@ -184,8 +184,9 @@ 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),