[Qemu-devel] [PATCH 34/56] qcow2: Avoid making the L1 table too big

[Michael Roth]

From: Max Reitz <mre...@redhat.com>

We refuse to open images whose L1 table we deem "too big". Consequently,
we should not produce such images ourselves.

Cc: qemu-sta...@nongnu.org
Signed-off-by: Max Reitz <mre...@redhat.com>
Message-id: 20160615153630.2116-3-mre...@redhat.com
Reviewed-by: Eric Blake <ebl...@redhat.com>
[mreitz: Added QEMU_BUILD_BUG_ON()]
Signed-off-by: Max Reitz <mre...@redhat.com>

(cherry picked from commit 84c26520d3c1c9ff4a10455748139463278816d5)
Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com>
---
 block/qcow2-cluster.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 31ecc10..22bdb47 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -64,7 +64,8 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t 
min_size,
         }
     }
 
-    if (new_l1_size > INT_MAX / sizeof(uint64_t)) {
+    QEMU_BUILD_BUG_ON(QCOW_MAX_L1_SIZE > INT_MAX);
+    if (new_l1_size > QCOW_MAX_L1_SIZE / sizeof(uint64_t)) {
         return -EFBIG;
     }
 
-- 
1.9.1