[Qemu-devel] [PULL 13/53] block/parallels: fix access to not initialized memory in catalog_bitmap

[Stefan Hajnoczi <stefanha@redhat.com>]

From: "Denis V. Lunev" <den@openvz.org>

found by valgrind.

Command: ./qemu-img convert -f parallels -O qcow2 1.hds 1.img
Invalid read of size 4
   at 0x17D0EF: parallels_co_read (parallels.c:357)
   by 0x11FEE4: bdrv_aio_rw_vector (block.c:4640)
   by 0x11FFBF: bdrv_aio_readv_em (block.c:4652)
   by 0x11F55F: bdrv_co_readv_em (block.c:4862)
   by 0x123428: bdrv_aligned_preadv (block.c:3056)
   by 0x1239FA: bdrv_co_do_preadv (block.c:3162)
   by 0x125424: bdrv_rw_co_entry (block.c:2706)
   by 0x155DD9: coroutine_trampoline (coroutine-ucontext.c:118)
   by 0x6975B6F: ??? (in /lib/x86_64-linux-gnu/libc-2.19.so)

The problem is that s->catalog_bitmap is allocated/filled as
gmalloc(s->catalog_size) thus index validity check must be
inclusive, i.e. index >= s->catalog_size is invalid.

Signed-off-by: Denis V. Lunev <den@openvz.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1412759610-2257-4-git-send-email-den@openvz.org
CC: Jeff Cody <jcody@redhat.com>
CC: Kevin Wolf <kwolf@redhat.com>
CC: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 block/parallels.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/parallels.c b/block/parallels.c
index 2a814f3..4f9cd8d 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -155,7 +155,7 @@ static int64_t seek_to_sector(BlockDriverState *bs, int64_t sector_num)
     offset = sector_num % s->tracks;
 
     /* not allocated */
-    if ((index > s->catalog_size) || (s->catalog_bitmap[index] == 0))
+    if ((index >= s->catalog_size) || (s->catalog_bitmap[index] == 0))
         return -1;
     return
         ((uint64_t)s->catalog_bitmap[index] * s->off_multiplier + offset) * 512;
-- 
1.9.3