# -*- 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 import sys import httplib import ssl from threading import Semaphore from logging import debug from Config import Config from Exceptions import ParameterError if not 'CertificateError ' in ssl.__dict__: class CertificateError(Exception): pass ssl.CertificateError = 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 match_hostname_aws(self, cert, e): """ 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. """ debug(u'checking SSL subjectAltName against amazonaws.com') san = cert.get('subjectAltName', ()) for key, value in san: if key == 'DNS': if value.startswith('*.s3') and \ (value.endswith('.amazonaws.com') and self.hostname.endswith('.amazonaws.com')) or \ (value.endswith('.amazonaws.com.cn') and self.hostname.endswith('.amazonaws.com.cn')): return raise e 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 ssl.CertificateError, e: self.match_hostname_aws(cert, e) @staticmethod def _https_connection(hostname, port=None): check_hostname = True try: context = http_connection._ssl_context() # S3's wildcart certificate doesn't work with DNS-style named buckets. if (hostname.endswith('.amazonaws.com') or hostname.endswith('.amazonaws.com.cn')): # 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'Recognized AWS S3 host, disabling initial SSL hostname check') check_hostname = False if context: context.check_hostname = False 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 self.hostname = hostname if not ssl: if cfg.proxy_host != "": self.c = httplib.HTTPConnection(cfg.proxy_host, cfg.proxy_port) debug(u'proxied HTTPConnection(%s, %s)' % (cfg.proxy_host, cfg.proxy_port)) else: self.c = httplib.HTTPConnection(hostname) debug(u'non-proxied HTTPConnection(%s)' % hostname) else: if cfg.proxy_host != "": self.c = http_connection._https_connection(cfg.proxy_host, cfg.proxy_port) self.c.set_tunnel(hostname) debug(u'proxied HTTPSConnection(%s, %s)' % (cfg.proxy_host, cfg.proxy_port)) debug(u'tunnel to %s' % hostname) else: self.c = http_connection._https_connection(hostname) debug(u'non-proxied HTTPSConnection(%s)' % hostname) class ConnMan(object): 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 not ConnMan.conn_pool.has_key(conn_id): 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))