Linux credentials-passing is no longer tested

Submitted by Simon McVittie

Assigned to Telepathy bugs list

Link to original bug (#45443)

Description

Recent Linux has this commit:

commit 16e5726269611b71c930054ffe9b858c1cea88eb Author: Eric Dumazet eric.dumazet@gmail.com Date: 2011-09-19 05:52:27 +0000

af_unix: dont send SCM_CREDENTIALS by default

Since commit 7361c36c5224 (af_unix: Allow credentials to work across
user and pid namespaces) af_unix performance dropped a lot.

... This patch includes SCM_CREDENTIALS information in a af_unix message/skb only if requested by the sender, [man 7 unix for details how to include ancillary data using sendmsg() system call]

Note: This might break buggy applications that expected SCM_CREDENTIAL
from an unaware write() system call, and receiver not using SO_PASSCRED
socket option.

If SOCK_PASSCRED is set on source or destination socket, we still
include credentials for mere write() syscalls.

so we need to do at least one of these:

• teach the Python (Twisted) code to send ancillary data (probably somewhat difficult)

• have Gabble enable SO_PASSCRED before telling the Tubes client about the socket, instead of enabling it just in time for the relevant read, and keep it enabled until the creds have been passed

Version: git master