# -*- coding: utf-8 -*-
## Amazon S3 manager
## Author: Michal Ludvig <michal@logix.cz>
## http://www.logix.cz/michal
## License: GPL Version 2
## Copyright: TGRMN Software and contributors
from __future__ import absolute_import
import sys
if sys.version_info >= (3,0):
from .Custom_httplib3x import httplib
else:
from .Custom_httplib27 import httplib
import ssl
from threading import Semaphore
from logging import debug
try:
# python 3 support
from urlparse import urlparse
except ImportError:
from urllib.parse import urlparse
from .Config import Config
from .Exceptions import ParameterError
from .Utils import getBucketFromHostname
if not 'CertificateError' in ssl.__dict__:
class CertificateError(Exception):
pass
else:
CertificateError = ssl.CertificateError
__all__ = [ "ConnMan" ]
class http_connection(object):
context = None
context_set = False
@staticmethod
def _ssl_verified_context(cafile):
cfg = Config()
context = None
try:
context = ssl.create_default_context(cafile=cafile)
except AttributeError: # no ssl.create_default_context
pass
if context and not cfg.check_ssl_hostname:
context.check_hostname = False
debug(u'Disabling SSL certificate hostname checking')
return context
@staticmethod
def _ssl_unverified_context(cafile):
debug(u'Disabling SSL certificate checking')
context = None
try:
context = ssl._create_unverified_context(cafile=cafile,
cert_reqs=ssl.CERT_NONE)
except AttributeError: # no ssl._create_unverified_context
pass
return context
@staticmethod
def _ssl_context():
if http_connection.context_set:
return http_connection.context
cfg = Config()
cafile = cfg.ca_certs_file
if cafile == "":
cafile = None
debug(u"Using ca_certs_file %s", cafile)
if cfg.check_ssl_certificate:
context = http_connection._ssl_verified_context(cafile)
else:
context = http_connection._ssl_unverified_context(cafile)
http_connection.context = context
http_connection.context_set = True
return context
def forgive_wildcard_cert(self, cert, hostname):
"""
Wildcard matching for *.s3.amazonaws.com and similar per region.
Per http://docs.aws.amazon.com/AmazonS3/latest/dev/BucketRestrictions.html:
"We recommend that all bucket names comply with DNS naming conventions."
Per http://docs.aws.amazon.com/AmazonS3/latest/dev/VirtualHosting.html:
"When using virtual hosted-style buckets with SSL, the SSL
wild card certificate only matches buckets that do not contain
periods. To work around this, use HTTP or write your own
certificate verification logic."
Therefore, we need a custom validation routine that allows
mybucket.example.com.s3.amazonaws.com to be considered a valid
hostname for the *.s3.amazonaws.com wildcard cert, and for the
region-specific *.s3-[region].amazonaws.com wildcard cert.
We also forgive non-S3 wildcard certificates should the
hostname match, to allow compatibility with other S3
API-compatible storage providers.
"""
debug(u'checking SSL subjectAltName as forgiving wildcard cert')
san = cert.get('subjectAltName', ())
hostname = hostname.lower()
cleaned_host_bucket_config = urlparse('https://' + Config.host_bucket).hostname
for key, value in san:
if key == 'DNS':
value = value.lower()
if value.startswith('*.s3') and \
(value.endswith('.amazonaws.com') and hostname.endswith('.amazonaws.com')) or \
(value.endswith('.amazonaws.com.cn') and hostname.endswith('.amazonaws.com.cn')):
return True
elif value == cleaned_host_bucket_config % \
{'bucket': '*', 'location': Config.bucket_location.lower()} and \
hostname.endswith(cleaned_host_bucket_config % \
{'bucket': '', 'location': Config.bucket_location.lower()}):
return True
return False
def match_hostname(self):
cert = self.c.sock.getpeercert()
try:
ssl.match_hostname(cert, self.hostname)
except AttributeError: # old ssl module doesn't have this function
return
except ValueError: # empty SSL cert means underlying SSL library didn't validate it, we don't either.
return
except CertificateError as e:
if not self.forgive_wildcard_cert(cert, self.hostname):
raise e
@staticmethod
def _https_connection(hostname, port=None):
try:
context = http_connection._ssl_context()
# Wilcard certificates do not work with DNS-style named buckets.
bucket_name, success = getBucketFromHostname(hostname)
if success and '.' in bucket_name:
# this merely delays running the hostname check until
# after the connection is made and we get control
# back. We then run the same check, relaxed for S3's
# wildcard certificates.
debug(u'Bucket name contains "." character, disabling initial SSL hostname check')
check_hostname = False
if context:
context.check_hostname = False
else:
if context:
check_hostname = context.check_hostname
else:
# Earliest version of python that don't have context,
# don't check hostnames anyway
check_hostname = True
# Note, we are probably needed to try to set check_hostname because of that bug:
# http://bugs.python.org/issue22959
conn = httplib.HTTPSConnection(hostname, port, context=context, check_hostname=check_hostname)
debug(u'httplib.HTTPSConnection() has both context and check_hostname')
except TypeError:
try:
# in case check_hostname parameter is not present try again
conn = httplib.HTTPSConnection(hostname, port, context=context)
debug(u'httplib.HTTPSConnection() has only context')
except TypeError:
# in case even context parameter is not present try one last time
conn = httplib.HTTPSConnection(hostname, port)
debug(u'httplib.HTTPSConnection() has neither context nor check_hostname')
return conn
def __init__(self, id, hostname, ssl, cfg):
self.ssl = ssl
self.id = id
self.counter = 0
# Whatever is the input, ensure to have clean hostname and port
parsed_hostname = urlparse('https://' + hostname)
self.hostname = parsed_hostname.hostname
self.port = parsed_hostname.port
if parsed_hostname.path and parsed_hostname.path != '/':
self.path = parsed_hostname.path.rstrip('/')
debug(u'endpoint path set to %s', self.path)
else:
self.path = None
"""
History note:
In a perfect world, or in the future:
- All http proxies would support CONNECT/tunnel, and so there would be no need
for using "absolute URIs" in format_uri.
- All s3-like servers would work well whether using relative or ABSOLUTE URIs.
But currently, what is currently common:
- Proxies without support for CONNECT for http, and so "absolute URIs" have to
be used.
- Proxies with support for CONNECT for httpS but s3-like servers having issues
with "absolute URIs", so relative one still have to be used as the requests will
pass as-is, through the proxy because of the CONNECT mode.
"""
if not cfg.proxy_host:
if ssl:
self.c = http_connection._https_connection(self.hostname, self.port)
debug(u'non-proxied HTTPSConnection(%s, %s)', self.hostname, self.port)
else:
self.c = httplib.HTTPConnection(self.hostname, self.port)
debug(u'non-proxied HTTPConnection(%s, %s)', self.hostname, self.port)
else:
if ssl:
self.c = http_connection._https_connection(cfg.proxy_host, cfg.proxy_port)
debug(u'proxied HTTPSConnection(%s, %s)', cfg.proxy_host, cfg.proxy_port)
port = self.port and self.port or 443
self.c.set_tunnel(self.hostname, port)
debug(u'tunnel to %s, %s', self.hostname, port)
else:
self.c = httplib.HTTPConnection(cfg.proxy_host, cfg.proxy_port)
debug(u'proxied HTTPConnection(%s, %s)', cfg.proxy_host, cfg.proxy_port)
# No tunnel here for the moment
class ConnMan(object):
_CS_REQ_SENT = httplib._CS_REQ_SENT
CONTINUE = httplib.CONTINUE
conn_pool_sem = Semaphore()
conn_pool = {}
conn_max_counter = 800 ## AWS closes connection after some ~90 requests
@staticmethod
def get(hostname, ssl = None):
cfg = Config()
if ssl == None:
ssl = cfg.use_https
conn = None
if cfg.proxy_host != "":
if ssl and sys.hexversion < 0x02070000:
raise ParameterError("use_https=True can't be used with proxy on Python <2.7")
conn_id = "proxy://%s:%s" % (cfg.proxy_host, cfg.proxy_port)
else:
conn_id = "http%s://%s" % (ssl and "s" or "", hostname)
ConnMan.conn_pool_sem.acquire()
if conn_id not in ConnMan.conn_pool:
ConnMan.conn_pool[conn_id] = []
if len(ConnMan.conn_pool[conn_id]):
conn = ConnMan.conn_pool[conn_id].pop()
debug("ConnMan.get(): re-using connection: %s#%d" % (conn.id, conn.counter))
ConnMan.conn_pool_sem.release()
if not conn:
debug("ConnMan.get(): creating new connection: %s" % conn_id)
conn = http_connection(conn_id, hostname, ssl, cfg)
conn.c.connect()
if conn.ssl and cfg.check_ssl_certificate and cfg.check_ssl_hostname:
conn.match_hostname()
conn.counter += 1
return conn
@staticmethod
def put(conn):
if conn.id.startswith("proxy://"):
conn.c.close()
debug("ConnMan.put(): closing proxy connection (keep-alive not yet supported)")
return
if conn.counter >= ConnMan.conn_max_counter:
conn.c.close()
debug("ConnMan.put(): closing over-used connection")
return
ConnMan.conn_pool_sem.acquire()
ConnMan.conn_pool[conn.id].append(conn)
ConnMan.conn_pool_sem.release()
debug("ConnMan.put(): connection put back to pool (%s#%d)" % (conn.id, conn.counter))