[PATCH] utils: Avoid returning loopback address from get_hostname_by_route

[David Ward]

Until recently, NetworkManager modified /etc/hosts and added the (real)
hostname as an alias to the loopback address 127.0.0.1, and also as an
alias to the IP address of the interface(s) it managed. In this situation,
func actually detected the hostname as "127.0.0.1", which was then used by
certmaster as the key name in the certificate. Even though the current
NetworkManager does not touch /etc/hosts, func should be able to handle
this case. This change includes the needed fixes to get_hostname_by_route.

Other code in this function has been edited to improve clarity.

Signed-off-by: David Ward <david.ward-***@public.gmane.org>
---
func/utils.py | 45 +++++++++++++++------------------------------
1 files changed, 15 insertions(+), 30 deletions(-)

diff --git a/func/utils.py b/func/utils.py
index fd456c1..41a75d8 100644
--- a/func/utils.py
+++ b/func/utils.py
@@ -80,8 +80,6 @@ def get_hostname_by_route():
"""
# FIXME: this code ignores http proxies (which granted, we don't
# support elsewhere either.
- hostname = None
- ip = None

minion_config_file = '/etc/func/minion.conf'
minion_config = read_config(minion_config_file, FuncdConfig)
@@ -98,50 +96,37 @@ def get_hostname_by_route():
server = cm_config.certmaster
port = cm_config.certmaster_port

+ s = socket.socket()
+ s.settimeout(5)
+ s.connect_ex((server, port))
+ (intf, port) = s.getsockname()
+ s.close()
+
try:
- s = socket.socket()
- s.settimeout(5)
- s.connect((server, port))
- (intf, port) = s.getsockname()
- # this can fail if there is no reverse DNS available
- intf_hostname = socket.gethostbyaddr(intf)[0]
- ip = socket.gethostbyname(intf_hostname)
- # not talking via localhost? good enough...
- if ip != '127.0.0.1':
- s.close()
- return intf_hostname.lower()
+ return socket.gethostbyaddr(intf)[0]
except:
- s.close()
- # something failed, reverse dns, etc
+ pass

# try to find the hostname of the ip we're listening on
if minion_config.listen_addr:
try:
- (hostname, aliases, ips) = socket.gethostbyaddr(minion_config.listen_addr)
+ return socket.gethostbyaddr(minion_config.listen_addr)[0]
except:
- hostname = None
+ pass

# in an ideal world, this would return exactly what we want: the most meaningful hostname
# for a system, but that is often not that case
- if hostname is None:
- hostname = socket.gethostname()
-
- # "localhost" is a really crappy hostname, so is pretty much anything attached
- # to 127.0.0.1, so try for something better
try:
+ hostname = socket.gethostname()
ip = socket.gethostbyname(hostname)
+ if ip != "127.0.0.1" and ip != "::1":
+ return hostname.lower()
except:
- hostname = None
-
- # non loopback is about as good as we can do for a guess
- if ip != "127.0.0.1" and hostname is not None:
- return hostname.lower()
-
-
+ pass

# all else has failed to get a good hostname, so just return
# an ip address
- return socket.gethostbyname(socket.gethostname()).lower() # yes I know it's an ip but I don't trust anything
+ return intf

def find_files_by_hostname(hostglob, filepath, fileext=''):
"""look for files in the given filepath with the given extension that

[seth vidal]

Post by David Ward
Until recently, NetworkManager modified /etc/hosts and added the (real)
hostname as an alias to the loopback address 127.0.0.1, and also as an
alias to the IP address of the interface(s) it managed. In this situation,
func actually detected the hostname as "127.0.0.1", which was then used by
certmaster as the key name in the certificate. Even though the current
NetworkManager does not touch /etc/hosts, func should be able to handle
this case. This change includes the needed fixes to get_hostname_by_route.
Other code in this function has been edited to improve clarity.

This looks great. Thank you.

applied
-sv