Commit cf2f225e26 ("af_unix: Put a socket into a per-netns hash table.")
accidentally broke user API for pathname sockets. A socket was able to
connect() to a pathname socket whose file was visible even if they were in
different network namespaces.
The commit puts all sockets into a per-netns hash table. As a result,
connect() to a pathname socket in a different netns fails to find it in the
caller's per-netns hash table and returns -ECONNREFUSED even when the task
can view the peer socket file.
We can reproduce this issue by:
Console A:
# python3
>>> from socket import *
>>> s = socket(AF_UNIX, SOCK_STREAM, 0)
>>> s.bind('test')
>>> s.listen(32)
Console B:
# ip netns add test
# ip netns exec test sh
# python3
>>> from socket import *
>>> s = socket(AF_UNIX, SOCK_STREAM, 0)
>>> s.connect('test')
Note when dumping sockets by sock_diag, procfs, and bpf_iter, they are
filtered only by netns. In other words, even if they are visible and
connect()able, all sockets in different netns are skipped while iterating
sockets. Thus, we need a fix only for finding a peer pathname socket.
This patch adds a global hash table for pathname sockets, links them with
sk_bind_node, and uses it in unix_find_socket_byinode(). By doing so, we
can keep sockets in per-netns hash tables and dump them easily.
Thanks to Sachin Sant and Leonard Crestez for reports, logs and a reproducer.
Fixes: cf2f225e26 ("af_unix: Put a socket into a per-netns hash table.")
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Reported-by: Leonard Crestez <cdleonard@gmail.com>
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Tested-by: Leonard Crestez <cdleonard@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
51bae889fe