[Qemu-block] [PULL for-2.9 02/10] rbd: Fix to cleanly reject -drive without pool or image

[Jeff Cody]

From: Markus Armbruster <address@hidden>

qemu_rbd_open() neglects to check pool and image are present.  Missing
image is caught by rbd_open(), but missing pool crashes.  Reproducer:

    $ qemu-system-x86_64 -nodefaults -drive driver=rbd,id=rbd,image=i,...
    terminate called after throwing an instance of 'std::logic_error'
      what():  basic_string::_M_construct null not valid
    Aborted (core dumped)

where ... is a working server.0.{host,port} configuration.

Doesn't affect -drive with file=..., because qemu_rbd_parse_filename()
always sets both pool and image.

Doesn't affect -blockdev, because pool and image are mandatory in the
QAPI schema.

Fix by adding the missing checks.

Signed-off-by: Markus Armbruster <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
Reviewed-by: Jeff Cody <address@hidden>
Message-id: address@hidden
Signed-off-by: Jeff Cody <address@hidden>
---
 block/rbd.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/block/rbd.c b/block/rbd.c
index ee13f3d..5ba2a87 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -711,6 +711,12 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict 
*options, int flags,
     name           = qemu_opt_get(opts, "image");
     keypairs       = qemu_opt_get(opts, "keyvalue-pairs");
 
+    if (!pool || !name) {
+        error_setg(errp, "Parameters 'pool' and 'image' are required");
+        r = -EINVAL;
+        goto failed_opts;
+    }
+
     r = rados_create(&s->cluster, clientname);
     if (r < 0) {
         error_setg_errno(errp, -r, "error initializing");
@@ -718,9 +724,7 @@ static int qemu_rbd_open(BlockDriverState *bs, QDict 
*options, int flags,
     }
 
     s->snap = g_strdup(snap);
-    if (name) {
-        pstrcpy(s->name, RBD_MAX_IMAGE_NAME_SIZE, name);
-    }
+    pstrcpy(s->name, RBD_MAX_IMAGE_NAME_SIZE, name);
 
     /* try default location when conf=NULL, but ignore failure */
     r = rados_conf_read_file(s->cluster, conf);
-- 
2.9.3