Patchwork [26/43] qcow2: Fix refcount table size calculation

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Submitter Michael Roth
Date Dec. 3, 2012, 10:08 p.m.
Message ID <1354572547-21271-27-git-send-email-mdroth@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/203469/
State New
Headers show

Comments

Michael Roth - Dec. 3, 2012, 10:08 p.m.
From: Kevin Wolf <kwolf@redhat.com>

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>
(cherry picked from commit a3548077062dd9dc2701ebffd931ba6eaef40bec)

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 block/qcow2-refcount.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Patch

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 5e3f915..96224d1 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);