NAME

       xdg-dbus-proxy - D-Bus proxy

SYNOPSIS

       xdg-dbus-proxy [OPTION...] [ADDRESS PATH [OPTION...]...]

DESCRIPTION

       xdg-dbus-proxy is a filtering proxy for D-Bus connections. Its arguments are one or more
       ADDRESS-PATH pairs specifying the buses to proxy, with options that specify what filtering
       to apply.

   Basic Operation
       The proxy listens to the unix domain socket at PATH, and for each client that connects to
       the socket, it opens up a new connection to the specified D-Bus ADDRESS (typically the
       session bus) and forwards data between the two. During the authentication phase all data
       is forwarded as received, and additionally for the first 1 byte zero we also send the
       proxy credentials to the bus.

       Once the connection is authenticated there are two modes, filtered and unfiltered. In the
       unfiltered mode all messages are sent on as they are received. In the filtering mode
       policy is applied to determine which messages to allow, and which to drop.

       Filtering is applied only to outgoing signals and method calls and incoming broadcast
       signals. All replies (errors or method returns) are allowed once for an outstanding method
       call, and never otherwise.

       If a client ever receives a message from another peer on the bus, the senders unique name
       is made visible, so the client can track caller lifetimes via NameOwnerChanged signals. If
       a client calls a method on or receives a broadcast signal from a name (even if filtered to
       some subset of paths or interfaces), that names basic policy is considered to be (at
       least) TALK, from then on.

   Policy
       The policy for the filtering consists of a mapping from well-known names to a policy that
       is either SEE, TALK or OWN. The default initial policy is that the the user is only
       allowed to TALK to the bus itself (org.freedesktop.DBus, or no destination specified), and
       TALK to its own unique ID. All other clients are invisible.

       Here is a description of the policy levels (each level implies the ones before it):

       SEE
           The name/ID is visible in the ListNames reply

           The name/ID is visible in the ListActivatableNames reply

           You can call GetNameOwner on the name

           You can call NameHasOwner on the name

           You see NameOwnerChanged signals on the name

           You see NameOwnerChanged signals on the ID when the client disconnects

           You can call the GetXXX methods on the name/ID to get e.g. the peer pid

           You get AccessDenied rather than NameHasNoOwner when sending messages to the name/ID

       TALK
           You can send any method calls and signals to the name/ID

           You will receive broadcast signals from the name/ID (if you have a match rule for
           them)

           You can call StartServiceByName on the name

       OWN
           You are allowed to call RequestName/ReleaseName/ListQueuedOwners on the name

       Policy is specified with the --see, --talk and --own options. The well-known names in
       these options can have a '.*' suffix. A name of "org.foo.*" matches "org.foo",
       org.foo.bar", and "org.foo.bar.gazonk", but not "org.foobar".

       Polices are specified for well-known names, but they also affect the owner of that name,
       so that the policy for a unique ID is the union of the polices for all the names it owns.
       For technical reasons, the policy for a unique name is "sticky", in that the highest
       policy granted by a once-owned name is kept, even when the client releases that name. This
       is impossible to avoid in a race-free way in a proxy. But it is rarely a problem in
       practice, as few clients release names and stay on the bus.

       In addition to the basic SEE/TALK/OWN policy, it is possible to specify more complicated
       rules about what method calls can be made on and what broadcast signals can be received
       from well-known names. A rule can restrict the allowed calls/signals to a specific object
       path or a subtree of object paths, and it can restrict the allowed interface down to an
       individual method or signal name.

       Rules are specified with the --call and --broadcast options. The RULE in these options
       determines what interfaces, methods and object paths are allowed. It must be of the form
       [METHOD][@PATH], where METHOD can be either '*' or a D-Bus interface, possible with a '.*'
       suffix, or a fully-qualified method name, and PATH is a D-Bus object path, possible with a
       '/*' suffix.

OPTIONS

       When options are used multiple times, the last option wins, unless otherwise specified.

       General options:

       --help
           Print help and exit

       --version
           Print version

       --fd=FD
           Write to FD when the proxies are ready, and stop when it is closed.

       --args=FD
           Parse nul-separated arguments from the given file descriptor. This option can be used
           multiple times to parse options from multiple sources.

       Proxy Options:

       These options can only be used after an ADDRESS and apply to the proxy for that address.

       --filter
           Enable filtering

       --log
           Turn on logging

       --sloppy-names
           Make all unique names visible.

       --see=NAME
           Set the SEE policy for the given name.

       --talk=NAME
           Set the TALK policy for the given name.

       --own=NAME
           Set the OWN policy for the given name.

       --call=NAME=RULE
           Set a rule for calls on the given name.

       --broadcast=NAME=RULE
           Set a rule for broadcast signals from the given name.

EXAMPLES

       $ xdg-dbus-proxy --fd=26 unix:path=/run/usr/1000/bus
       /run/usr/1000/.dbus-proxy/session-bus-proxy --filter --own=org.gnome.ghex.*
       --talk=ca.desrt.dconf --call=org.freedesktop.portal.*=*
       --broadcast=org.freedesktop.portal.*=@/org/freedesktop/portal/*