[Qemu-devel] [PATCH v1 04/15] qcow: require image size to be > 1 for new images

["Daniel P. Berrange" <berrange@redhat.com>]

The qcow driver refuses to open images which are less than
2 bytes in size, but will happily create such images. Add
a check in the create path to avoid this discrepancy.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 block/qcow.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block/qcow.c b/block/qcow.c
index 7540f43..8133fda 100644
--- a/block/qcow.c
+++ b/block/qcow.c
@@ -799,6 +799,12 @@ static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
     /* Read out options */
     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
                           BDRV_SECTOR_SIZE);
+    if (total_size <= 1) {
+        error_setg(errp, "Image size is too small (must be at least 2 bytes)");
+        ret = -EINVAL;
+        goto cleanup;
+    }
+
     backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
     if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
         flags |= BLOCK_FLAG_ENCRYPT;
-- 
2.9.3