BUG/MINOR: sock_unix: match finalname with tempname in sock_unix_addrcmp()

In sock_unix_addrcmp(), named UNIX sockets paths are manually compared in
order to properly handle tempname paths (ending with ".XXXX.tmp") that result
from the 2-step bind implemented in sock_unix_bind_receiver().

However, this logic does not take into account "final" path names (without the
".XXXX.tmp" suffix).

Example:
  /tmp/test did not match with /tmp/test.1288.tmp prior to this patch

Indeed, depending on how the socket addr is retrieved, the same socket
could be designated either by its tempname or finalname.
socket addr is normally stored with its finalname within a receiver, but a
call to getsockname() on the same socket will return the tempname that was
used for the bind() call (sock_get_old_sockets() depends on getsockname()).

This causes sock_find_compatible_fd() to malfunction with named UNIX
sockets (ie: haproxy -x CLI option).

To fix this, we slightly modify the check around the temp suffix in
sock_unix_addrcmp(): we perform the suffix check even if one of the
paths is lacking the temp suffix (with proper precautions).

Now the function is able to match:
  - finalname x finalname
  - tempname  x tempname
  - finalname x tempname

That is: /tmp/test == /tmp/test.1288.tmp == /tmp/test.X.tmp

It should be backported up to 2.4
1 file changed