ui: deprecate "password" option for SPICE server

With the new "password-secret" option, there is no reason to use the old
inecure "password" option with -spice, so it can be deprecated.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210311114343.439820-4-berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

docs/system/deprecated.rst

@@ -174,6 +174,14 @@ Input parameters that take a size value should only use a size suffix
 the value is hexadecimal.  That is, '0x20M' is deprecated, and should
 be written either as '32M' or as '0x2000000'.
 
+``-spice password=string`` (since 6.0)
+''''''''''''''''''''''''''''''''''''''
+
+This option is insecure because the SPICE password remains visible in
+the process listing. This is replaced by the new ``password-secret``
+option which lets the password be securely provided on the command
+line using a ``secret`` object instance.
+
 QEMU Machine Protocol (QMP) commands
 ------------------------------------
 

qemu-options.hx

@@ -1928,6 +1928,10 @@ SRST
     ``password=<string>``
         Set the password you need to authenticate.
 
+        This option is deprecated and insecure because it leaves the
+        password visible in the process listing. Use ``password-secret``
+        instead.
+
     ``password-secret=<secret-id>``
         Set the ID of the ``secret`` object containing the password
         you need to authenticate.

ui/spice-core.c

@@ -686,6 +686,8 @@ static void qemu_spice_init(void)
     } else {
         str = qemu_opt_get(opts, "password");
         if (str) {
+            warn_report("'password' option is deprecated and insecure, "
+                        "use 'password-secret' instead");
             password = g_strdup(str);
         }
     }