On 16.10.2014 15:25, Max Reitz wrote:
While writing an L1 table sector, qcow2_write_l1_entry() copies the
respective range from s->l1_table to the local "buf" array. The size of
s->l1_table does not have to be a multiple of L1_ENTRIES_PER_SECTOR;
thus, limit the index which is used for copying all entries to the L1
size.

Cc: qemu-sta...@nongnu.org
Signed-off-by: Max Reitz <mre...@redhat.com>
---
  block/qcow2-cluster.c | 6 ++++--
  1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index f7dd8c0..4d888c7 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -164,12 +164,14 @@ static int l2_load(BlockDriverState *bs, uint64_t 
l2_offset,
  int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index)
  {
      BDRVQcowState *s = bs->opaque;
-    uint64_t buf[L1_ENTRIES_PER_SECTOR];
+    uint64_t buf[L1_ENTRIES_PER_SECTOR] = { 0 };
      int l1_start_index;
      int i, ret;
l1_start_index = l1_index & ~(L1_ENTRIES_PER_SECTOR - 1);
-    for (i = 0; i < L1_ENTRIES_PER_SECTOR; i++) {
+    for (i = 0; i < L1_ENTRIES_PER_SECTOR && l1_start_index + i < s->l1_size;
+         i++)
+    {
          buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]);
      }

Reviewed-by: Peter Lieven <p...@kamp.de>


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