[PULL v2 7/9] chardev/char.c: Always pass id to chardev_new

[marcandre . lureau]

From: Lukas Straub <lukasstraub2@web.de>

Always pass the id to chardev_new, since it is needed to register
the yank instance for the chardev. Also, after checking that
nothing calls chardev_new with id=NULL, assert() that id!=NULL.

This fixes a crash when using chardev-change to change a chardev
to chardev-socket, which attempts to register a yank instance.
This in turn tries to dereference the NULL-pointer.

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Tested-by: Li Zhang <li.zhang@cloud.ionos.com>
Message-Id: 
<3e669b6c160aa7278e37c4d95e0445574f96c7b7.1617127849.git.lukasstraub2@web.de>
---
 chardev/char.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/chardev/char.c b/chardev/char.c
index 48f321b3e1..75993f903f 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -967,6 +967,7 @@ static Chardev *chardev_new(const char *id, const char 
*typename,
     bool be_opened = true;
 
     assert(g_str_has_prefix(typename, "chardev-"));
+    assert(id);
 
     obj = object_new(typename);
     chr = CHARDEV(obj);
@@ -1095,12 +1096,11 @@ ChardevReturn *qmp_chardev_change(const char *id, 
ChardevBackend *backend,
         return NULL;
     }
 
-    chr_new = chardev_new(NULL, object_class_get_name(OBJECT_CLASS(cc)),
+    chr_new = chardev_new(id, object_class_get_name(OBJECT_CLASS(cc)),
                           backend, chr->gcontext, errp);
     if (!chr_new) {
         return NULL;
     }
-    chr_new->label = g_strdup(id);
 
     if (chr->be_open && !chr_new->be_open) {
         qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
-- 
2.29.0