From: Kevin Wolf <kwolf@redhat.com>
Date: Fri, 26 Oct 2012 14:33:32 +0000 (+0200)
Subject: qcow2: Fix refcount table size calculation
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a3548077062dd9dc2701ebffd931ba6eaef40bec;p=qemu.git

qcow2: Fix refcount table size calculation

A missing factor for the refcount table entry size in the calculation
could mean that too little memory was allocated for the in-memory
representation of the table, resulting in a buffer overflow.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Tested-by: Michael Tokarev <mjt@tls.msk.ru>
---

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 5e3f9153fb..96224d1af2 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -301,7 +301,8 @@ static int alloc_refcount_block(BlockDriverState *bs,
     uint64_t last_table_size;
     uint64_t blocks_clusters;
     do {
-        uint64_t table_clusters = size_to_clusters(s, table_size);
+        uint64_t table_clusters =
+            size_to_clusters(s, table_size * sizeof(uint64_t));
         blocks_clusters = 1 +
             ((table_clusters + refcount_block_clusters - 1)
             / refcount_block_clusters);