[Qemu-devel] [PATCH for-2.12 07/12] parallels: Check maximum cluster size on create

[Kevin Wolf <kwolf@redhat.com>]

It's unclear what the real maximum cluster size is for the Parallels
format, but let's at least make sure that we don't get integer
overflows in our .bdrv_co_create implementation.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/parallels.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/block/parallels.c b/block/parallels.c
index 2da5e56a9d..e4ca018c2e 100644
--- a/block/parallels.c
+++ b/block/parallels.c
@@ -526,6 +526,11 @@ static int coroutine_fn parallels_co_create(BlockdevCreateOptions* opts,
         cl_size = DEFAULT_CLUSTER_SIZE;
     }
 
+    /* XXX What is the real limit here? This is an insanely large maximum. */
+    if (cl_size >= UINT64_MAX / MAX_PARALLELS_IMAGE_FACTOR) {
+        error_setg(errp, "Cluster size is too large");
+        return -EINVAL;
+    }
     if (total_size >= MAX_PARALLELS_IMAGE_FACTOR * cl_size) {
         error_setg(errp, "Image size is too large for this cluster size");
         return -E2BIG;
-- 
2.13.6