View file File name : Crypto.py Content :# -*- 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 import hmac import base64 from . import Config from logging import debug from .Utils import encode_to_s3, time_to_epoch, deunicodise, decode_from_s3 from .SortedDict import SortedDict import datetime try: # python 3 support from urllib import quote except ImportError: from urllib.parse import quote from hashlib import sha1, sha256 __all__ = [] def format_param_str(params, always_have_equal=False, limited_keys=None): """ Format URL parameters from a params dict and returns ?parm1=val1&parm2=val2 or an empty string if there are no parameters. Output of this function should be appended directly to self.resource['uri'] - Set "always_have_equal" to always have the "=" char for a param even when there is no value for it. - Set "limited_keys" list to restrict the param string to keys that are defined in it. """ if not params: return "" param_str = "" equal_str = always_have_equal and u'=' or '' for key in sorted(params.keys()): if limited_keys and key not in limited_keys: continue value = params[key] if value in (None, ""): param_str += "&%s%s" % (s3_quote(key, unicode_output=True), equal_str) else: param_str += "&%s=%s" % (key, s3_quote(params[key], unicode_output=True)) return param_str and "?" + param_str[1:] __all__.append("format_param_str") ### AWS Version 2 signing def sign_string_v2(string_to_sign): """Sign a string with the secret key, returning base64 encoded results. By default the configured secret key is used, but may be overridden as an argument. Useful for REST authentication. See http://s3.amazonaws.com/doc/s3-developer-guide/RESTAuthentication.html string_to_sign should be utf-8 "bytes". """ secret_key = Config.Config().secret_key signature = base64.encodestring(hmac.new(encode_to_s3(secret_key), string_to_sign, sha1).digest()).strip() return signature __all__.append("sign_string_v2") def sign_request_v2(method='GET', canonical_uri='/', params=None, cur_headers=None): """Sign a string with the secret key, returning base64 encoded results. By default the configured secret key is used, but may be overridden as an argument. Useful for REST authentication. See http://s3.amazonaws.com/doc/s3-developer-guide/RESTAuthentication.html string_to_sign should be utf-8 "bytes". """ # valid sub-resources to be included in sign v2: SUBRESOURCES_TO_INCLUDE = ['acl', 'lifecycle', 'location', 'logging', 'notification', 'partNumber', 'policy', 'requestPayment', 'torrent', 'uploadId', 'uploads', 'versionId', 'versioning', 'versions', 'website', # Missing of aws s3 doc but needed 'delete', 'cors', 'restore'] if cur_headers is None: cur_headers = SortedDict(ignore_case = True) access_key = Config.Config().access_key string_to_sign = method + "\n" string_to_sign += cur_headers.get("content-md5", "") + "\n" string_to_sign += cur_headers.get("content-type", "") + "\n" string_to_sign += cur_headers.get("date", "") + "\n" for header in sorted(cur_headers.keys()): if header.startswith("x-amz-"): string_to_sign += header + ":" + cur_headers[header] + "\n" if header.startswith("x-emc-"): string_to_sign += header + ":"+ cur_headers[header] + "\n" canonical_uri = s3_quote(canonical_uri, quote_backslashes=False, unicode_output=True) canonical_querystring = format_param_str(params, limited_keys=SUBRESOURCES_TO_INCLUDE) # canonical_querystring would be empty if no param given, otherwise it will # starts with a "?" canonical_uri += canonical_querystring string_to_sign += canonical_uri debug("SignHeaders: " + repr(string_to_sign)) signature = decode_from_s3(sign_string_v2(encode_to_s3(string_to_sign))) new_headers = SortedDict(list(cur_headers.items()), ignore_case=True) new_headers["Authorization"] = "AWS " + access_key + ":" + signature return new_headers __all__.append("sign_request_v2") def sign_url_v2(url_to_sign, expiry): """Sign a URL in s3://bucket/object form with the given expiry time. The object will be accessible via the signed URL until the AWS key and secret are revoked or the expiry time is reached, even if the object is otherwise private. See: http://s3.amazonaws.com/doc/s3-developer-guide/RESTAuthentication.html """ return sign_url_base_v2( bucket = url_to_sign.bucket(), object = url_to_sign.object(), expiry = expiry ) __all__.append("sign_url_v2") def sign_url_base_v2(**parms): """Shared implementation of sign_url methods. Takes a hash of 'bucket', 'object' and 'expiry' as args.""" content_disposition=Config.Config().content_disposition content_type=Config.Config().content_type parms['expiry']=time_to_epoch(parms['expiry']) parms['access_key']=Config.Config().access_key parms['host_base']=Config.Config().host_base parms['object'] = s3_quote(parms['object'], quote_backslashes=False, unicode_output=True) parms['proto'] = 'http' if Config.Config().signurl_use_https: parms['proto'] = 'https' debug("Expiry interpreted as epoch time %s", parms['expiry']) signtext = 'GET\n\n\n%(expiry)d\n/%(bucket)s/%(object)s' % parms param_separator = '?' if content_disposition: signtext += param_separator + 'response-content-disposition=' + content_disposition param_separator = '&' if content_type: signtext += param_separator + 'response-content-type=' + content_type param_separator = '&' debug("Signing plaintext: %r", signtext) parms['sig'] = s3_quote(sign_string_v2(encode_to_s3(signtext)), unicode_output=True) debug("Urlencoded signature: %s", parms['sig']) url = "%(proto)s://%(bucket)s.%(host_base)s/%(object)s?AWSAccessKeyId=%(access_key)s&Expires=%(expiry)d&Signature=%(sig)s" % parms if content_disposition: url += "&response-content-disposition=" + s3_quote(content_disposition, unicode_output=True) if content_type: url += "&response-content-type=" + s3_quote(content_type, unicode_output=True) return url def sign(key, msg): return hmac.new(key, encode_to_s3(msg), sha256).digest() def getSignatureKey(key, dateStamp, regionName, serviceName): """ Input: unicode params Output: bytes """ kDate = sign(encode_to_s3('AWS4' + key), dateStamp) kRegion = sign(kDate, regionName) kService = sign(kRegion, serviceName) kSigning = sign(kService, 'aws4_request') return kSigning def sign_request_v4(method='GET', host='', canonical_uri='/', params=None, region='us-east-1', cur_headers=None, body=b''): service = 's3' if cur_headers is None: cur_headers = SortedDict(ignore_case = True) cfg = Config.Config() access_key = cfg.access_key secret_key = cfg.secret_key t = datetime.datetime.utcnow() amzdate = t.strftime('%Y%m%dT%H%M%SZ') datestamp = t.strftime('%Y%m%d') signing_key = getSignatureKey(secret_key, datestamp, region, service) canonical_uri = s3_quote(canonical_uri, quote_backslashes=False, unicode_output=True) canonical_querystring = format_param_str(params, always_have_equal=True).lstrip('?') if type(body) == type(sha256(b'')): payload_hash = decode_from_s3(body.hexdigest()) else: payload_hash = decode_from_s3(sha256(encode_to_s3(body)).hexdigest()) canonical_headers = {'host' : host, 'x-amz-content-sha256': payload_hash, 'x-amz-date' : amzdate } signed_headers = 'host;x-amz-content-sha256;x-amz-date' for header in cur_headers.keys(): # avoid duplicate headers and previous Authorization if header == 'Authorization' or header in signed_headers.split(';'): continue canonical_headers[header.strip()] = cur_headers[header].strip() signed_headers += ';' + header.strip() # sort headers into a string canonical_headers_str = '' for k, v in sorted(canonical_headers.items()): canonical_headers_str += k + ":" + v + "\n" canonical_headers = canonical_headers_str debug(u"canonical_headers = %s" % canonical_headers) signed_headers = ';'.join(sorted(signed_headers.split(';'))) canonical_request = method + '\n' + canonical_uri + '\n' + canonical_querystring + '\n' + canonical_headers + '\n' + signed_headers + '\n' + payload_hash debug('Canonical Request:\n%s\n----------------------' % canonical_request) algorithm = 'AWS4-HMAC-SHA256' credential_scope = datestamp + '/' + region + '/' + service + '/' + 'aws4_request' string_to_sign = algorithm + '\n' + amzdate + '\n' + credential_scope + '\n' + decode_from_s3(sha256(encode_to_s3(canonical_request)).hexdigest()) signature = decode_from_s3(hmac.new(signing_key, encode_to_s3(string_to_sign), sha256).hexdigest()) authorization_header = algorithm + ' ' + 'Credential=' + access_key + '/' + credential_scope + ',' + 'SignedHeaders=' + signed_headers + ',' + 'Signature=' + signature new_headers = SortedDict(cur_headers.items()) new_headers.update({'x-amz-date':amzdate, 'Authorization':authorization_header, 'x-amz-content-sha256': payload_hash}) debug("signature-v4 headers: %s" % new_headers) return new_headers __all__.append("sign_request_v4") def s3_quote(param, quote_backslashes=True, unicode_output=False): """ URI encode every byte. UriEncode() must enforce the following rules: - URI encode every byte except the unreserved characters: 'A'-'Z', 'a'-'z', '0'-'9', '-', '.', '_', and '~'. - The space character is a reserved character and must be encoded as "%20" (and not as "+"). - Each URI encoded byte is formed by a '%' and the two-digit hexadecimal value of the byte. - Letters in the hexadecimal value must be uppercase, for example "%1A". - Encode the forward slash character, '/', everywhere except in the object key name. For example, if the object key name is photos/Jan/sample.jpg, the forward slash in the key name is not encoded. """ if quote_backslashes: safe_chars = "~" else: safe_chars = "~/" param = encode_to_s3(param) param = quote(param, safe=safe_chars) if unicode_output: param = decode_from_s3(param) else: param = encode_to_s3(param) return param __all__.append("s3_quote") def checksum_sha256_file(filename, offset=0, size=None): try: hash = sha256() except: # fallback to Crypto SHA256 module hash = sha256.new() with open(deunicodise(filename),'rb') as f: if size is None: for chunk in iter(lambda: f.read(8192), b''): hash.update(chunk) else: f.seek(offset) size_left = size while size_left > 0: chunk = f.read(min(8192, size_left)) size_left -= len(chunk) hash.update(chunk) return hash def checksum_sha256_buffer(buffer, offset=0, size=None): try: hash = sha256() except: # fallback to Crypto SHA256 module hash = sha256.new() if size is None: hash.update(buffer) else: hash.update(buffer[offset:offset+size]) return hash