From: Max Reitz <mreitz@redhat.com>
Date: Wed, 15 Jun 2016 15:36:30 +0000 (+0200)
Subject: qcow2: Avoid making the L1 table too big
X-Git-Tag: v2.7.0-rc0~32^2^2~10
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=84c26520d3c1c9ff4a10455748139463278816d5;p=thirdparty%2Fqemu.git

qcow2: Avoid making the L1 table too big

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

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

diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 6b92ce9429b..00c16dcba56 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -65,7 +65,8 @@ 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;
     }