This is a version of #63481 for master.

CVE-2019-12447:
daemon/gvfsbackendadmin.c mishandles file ownership because setfsuid is
not used.

CVE-2019-12448:
daemon/gvfsbackendadmin.c has race conditions because the admin backend
doesn't implement query_info_on_read/write.

CVE-2019-12449:
daemon/gvfsbackendadmin.c mishandles a file's user and group ownership
during move (and copy with G_FILE_COPY_ALL_METADATA) operations
from admin:// to file:// URIs, because root privileges are unavailable.

Upstream MR: https://gitlab.gnome.org/GNOME/gvfs/merge_requests/48

This is a version of #63481 for master.

Vulnerability Description:
daemon/gvfsdaemon.c in gvfsd from GNOME gvfs before 1.38.3, 1.40.x before
1.40.2, and 1.41.x before 1.41.3 opened a private D-Bus server socket without
configuring an authorization rule. A local attacker could connect to this server
socket and issue D-Bus method calls. Note that the server socket only accepts
a single connection, so the attacker would have to discover the server and connect
to the socket before its owner does.

#63301

gvfs: security fixes