From 1c5f0ad98d25b7f77870ba541afbbedc65ddc355 Mon Sep 17 00:00:00 2001
From: Simon McVittie
Date: Fri, 11 Nov 2011 15:58:13 +0000
Subject: Redefine Socket_Access_Control_Credentials on D-Bus tubes to be
useful
I think this is what was always intended, and it seems to be what Gabble
has always implemented.
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=42809
---
spec/Channel_Interface_Tube.xml | 53 ++++++++++++++++++++++++++++++++---------
1 file changed, 42 insertions(+), 11 deletions(-)
diff --git a/spec/Channel_Interface_Tube.xml b/spec/Channel_Interface_Tube.xml
index 858a15dd..f31ab213 100644
--- a/spec/Channel_Interface_Tube.xml
+++ b/spec/Channel_Interface_Tube.xml
@@ -204,15 +204,24 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
array-name="Socket_Access_Control_List">
- The IP or Unix socket can be accessed by any local user (e.g.
- a Unix socket that accepts all local connections, or an IP socket
- listening on 127.0.0.1 (or ::1) or rejecting connections not from
- that address). The associated variant must be ignored.
+ The IP or Unix socket can be accessed by any local user (e.g.
+ a Unix socket that accepts all local connections, or an IP socket
+ listening on 127.0.0.1 (or ::1) or rejecting connections not from
+ that address). The associated variant must be ignored.
+
+ For a D-Bus tube, this means that the "same user" access
+ control typically provided by default in D-Bus implementations
+ SHOULD be disabled. If the socket is only available to local users
+ (e.g. a Unix socket, an IPv4 socket bound to 127.0.0.1, or an
+ IPv6 socket bound to ::1), the ANONYMOUS
+ authentication mechanism MAY be enabled.
- May only be used on IP sockets. The associated variant must contain
+ May only be used on IP sockets, and only for Stream tubes.
+
+ The associated variant must contain
a struct Socket_Address_IPv4 (or Socket_Address_IPv6)
containing the string form of an IP address of the appropriate
version, and a port number. The socket can only be accessed if the
@@ -235,19 +244,41 @@ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
- May only be used on UNIX sockets.
+
The high-level meaning of this access control type is that
+ only the same user (e.g. same numeric Unix uid) is allowed to
+ interact with the tube. Exactly how this is achieved varies by
+ channel type.
+
+ For StreamTube channels, this access control type
+ may only be used on UNIX sockets.
The connecting process must send a byte when
it first connects, which is not considered to be part of the data
stream. If the operating system uses sendmsg() with SCM_CREDS or
SCM_CREDENTIALS to pass credentials over sockets, the connecting
process must do so if possible; if not, it must still send the
- byte.
+ byte, without any attached credentials. (This mechanism is
+ very similar to the first byte of a D-Bus connection, except that
+ in D-Bus the byte is always zero, whereas in Tubes it can be
+ nonzero.)
+
+ For DBusTube channels, this access control type
+ may be used on any type of socket, and there is no extra byte
+ added by Telepathy at the beginning of the stream: all bytes in
+ the stream are part of the D-Bus tube connection. The connecting
+ process should prove its identity via any of the SASL
+ authentication mechanisms usually used for D-Bus (in typical
+ D-Bus implementations this involves either sending and receiving
+ credentials as above, or demonstrating the ability to write to a
+ file in the user's home directory).
- The listening process will disconnect the connection unless it
- can determine by OS-specific means that the connecting process
- has the same user ID as the listening process.
+ In either case, the listening process will disconnect the
+ connection unless it can determine by OS-specific means that
+ the connecting process has the same user ID as the listening
+ process.
- The associated variant must be ignored.
+ In either tube type, the associated variant must be ignored.
--
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