forked from indymedia/epicyon
251 lines
11 KiB
Python
251 lines
11 KiB
Python
__filename__ = "posts.py"
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__author__ = "Bob Mottram"
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__credits__ = ['lamia']
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__license__ = "AGPL3+"
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__version__ = "1.1.0"
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__maintainer__ = "Bob Mottram"
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__email__ = "bob@freedombone.net"
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__status__ = "Production"
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# see https://tools.ietf.org/html/draft-cavage-http-signatures-06
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from Cryptodome.PublicKey import RSA
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from Cryptodome.Hash import SHA256
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from Cryptodome.Signature import pkcs1_15
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#from Crypto.PublicKey import RSA
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#from Crypto.Hash import SHA256
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##from Crypto.Signature import PKCS1_v1_5
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#from Crypto.Signature import pkcs1_15
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from requests.auth import AuthBase
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import base64
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import json
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from time import gmtime, strftime
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import datetime
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from pprint import pprint
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def messageContentDigest(messageBodyJsonStr: str) -> str:
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return base64.b64encode(SHA256.new(messageBodyJsonStr.encode('utf-8')).digest()).decode('utf-8')
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def signPostHeaders(dateStr: str,privateKeyPem: str, \
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nickname: str, \
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domain: str,port: int, \
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toDomain: str,toPort: int, \
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path: str, \
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httpPrefix: str, \
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messageBodyJsonStr: str) -> str:
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"""Returns a raw signature string that can be plugged into a header and
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used to verify the authenticity of an HTTP transmission.
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"""
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if port:
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if port!=80 and port!=443:
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if ':' not in domain:
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domain=domain+':'+str(port)
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if toPort:
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if toPort!=80 and toPort!=443:
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if ':' not in toDomain:
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toDomain=toDomain+':'+str(port)
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if not dateStr:
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dateStr=strftime("%a, %d %b %Y %H:%M:%S %Z", gmtime())
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keyID=httpPrefix+'://'+domain+'/users/'+nickname+'#main-key'
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if not messageBodyJsonStr:
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headers={'(request-target)': f'post {path}','host': toDomain,'date': dateStr,'content-type': 'application/json'}
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else:
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bodyDigest=messageContentDigest(messageBodyJsonStr)
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contentLength=len(messageBodyJsonStr)
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headers={'(request-target)': f'post {path}','host': toDomain,'date': dateStr,'digest': f'SHA-256={bodyDigest}','content-type': 'application/activity+json','content-length': str(contentLength)}
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privateKeyPem=RSA.import_key(privateKeyPem)
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#headers.update({
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# '(request-target)': f'post {path}',
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#})
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# build a digest for signing
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signedHeaderKeys = headers.keys()
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signedHeaderText = ''
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for headerKey in signedHeaderKeys:
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signedHeaderText += f'{headerKey}: {headers[headerKey]}\n'
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#print(f'*********************signing: headerKey: {headerKey}: {headers[headerKey]}')
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signedHeaderText = signedHeaderText.strip()
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#print('******************************Send: signedHeaderText: '+signedHeaderText)
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headerDigest = SHA256.new(signedHeaderText.encode('ascii'))
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# Sign the digest
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rawSignature = pkcs1_15.new(privateKeyPem).sign(headerDigest)
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signature = base64.b64encode(rawSignature).decode('ascii')
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# Put it into a valid HTTP signature format
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signatureDict = {
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'keyId': keyID,
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'algorithm': 'rsa-sha256',
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'headers': ' '.join(signedHeaderKeys),
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'signature': signature
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}
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signatureHeader = ','.join(
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[f'{k}="{v}"' for k, v in signatureDict.items()])
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return signatureHeader
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def createSignedHeader(privateKeyPem: str,nickname: str, \
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domain: str,port: int, \
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toDomain: str,toPort: int, \
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path: str,httpPrefix: str,withDigest: bool, \
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messageBodyJsonStr: str) -> {}:
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"""Note that the domain is the destination, not the sender
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"""
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contentType='application/activity+json'
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headerDomain=toDomain
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if toPort:
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if toPort!=80 and toPort!=443:
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if ':' not in headerDomain:
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headerDomain=headerDomain+':'+str(toPort)
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dateStr=strftime("%a, %d %b %Y %H:%M:%S %Z", gmtime())
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if not withDigest:
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headers = {'(request-target)': f'post {path}','host': headerDomain,'date': dateStr}
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signatureHeader = \
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signPostHeaders(dateStr,privateKeyPem,nickname, \
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domain,port,toDomain,toPort, \
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path,httpPrefix,None)
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else:
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bodyDigest=messageContentDigest(messageBodyJsonStr)
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contentLength=len(messageBodyJsonStr)
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#print('***************************Send (request-target): post '+path)
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#print('***************************Send host: '+headerDomain)
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#print('***************************Send date: '+dateStr)
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#print('***************************Send digest: '+bodyDigest)
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#print('***************************Send Content-type: '+contentType)
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#print('***************************Send Content-Length: '+str(len(messageBodyJsonStr)))
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#print('***************************Send messageBodyJsonStr: '+messageBodyJsonStr)
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headers = {'(request-target)': f'post {path}','host': headerDomain,'date': dateStr,'digest': f'SHA-256={bodyDigest}','content-length': str(contentLength),'content-type': contentType}
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signatureHeader = \
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signPostHeaders(dateStr,privateKeyPem,nickname, \
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domain,port, \
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toDomain,toPort, \
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path,httpPrefix,messageBodyJsonStr)
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headers['signature'] = signatureHeader
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return headers
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def verifyRecentSignature(signedDateStr: str) -> bool:
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"""Checks whether the given time taken from the header is within
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12 hours of the current time
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"""
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currDate=datetime.datetime.utcnow()
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signedDate=datetime.datetime.strptime(signedDateStr,"%a, %d %b %Y %H:%M:%S %Z")
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timeDiffSec=(currDate-signedDate).seconds
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# 12 hours tollerance
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if timeDiffSec > 43200:
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print('WARN: Header signed too long ago: '+signedDateStr)
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print(str(timeDiffSec/(60*60))+' hours')
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return False
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if timeDiffSec < 0:
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print('WARN: Header signed in the future! '+signedDateStr)
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print(str(timeDiffSec/(60*60))+' hours')
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return False
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return True
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def verifyPostHeaders(httpPrefix: str,publicKeyPem: str,headers: dict, \
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path: str,GETmethod: bool, \
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messageBodyDigest: str, \
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messageBodyJsonStr: str,debug: bool) -> bool:
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"""Returns true or false depending on if the key that we plugged in here
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validates against the headers, method, and path.
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publicKeyPem - the public key from an rsa key pair
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headers - should be a dictionary of request headers
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path - the relative url that was requested from this site
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GETmethod - GET or POST
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messageBodyJsonStr - the received request body (used for digest)
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"""
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if GETmethod:
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method='GET'
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else:
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method='POST'
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if debug:
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print('DEBUG: verifyPostHeaders '+method)
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publicKeyPem = RSA.import_key(publicKeyPem)
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# Build a dictionary of the signature values
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signatureHeader = headers['signature']
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signatureDict = {
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k: v[1:-1]
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for k, v in [i.split('=', 1) for i in signatureHeader.split(',')]
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}
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#print('********************signatureHeader: '+str(signatureHeader))
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#print('********************signatureDict: '+str(signatureDict))
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# Unpack the signed headers and set values based on current headers and
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# body (if a digest was included)
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signedHeaderList = []
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for signedHeader in signatureDict['headers'].split(' '):
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if debug:
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print('DEBUG: verifyPostHeaders signedHeader='+signedHeader)
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if signedHeader == '(request-target)':
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signedHeaderList.append(
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f'(request-target): {method.lower()} {path}')
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#print('***************************Verify (request-target): '+method.lower()+' '+path)
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elif signedHeader == 'digest':
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if messageBodyDigest:
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bodyDigest=messageBodyDigest
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else:
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bodyDigest=messageContentDigest(messageBodyJsonStr)
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signedHeaderList.append(f'digest: SHA-256={bodyDigest}')
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#print('***************************Verify digest: SHA-256='+bodyDigest)
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#print('***************************Verify messageBodyJsonStr: '+messageBodyJsonStr)
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elif signedHeader == 'content-length':
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if headers.get(signedHeader):
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signedHeaderList.append(f'content-length: {headers[signedHeader]}')
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else:
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if headers.get('Content-Length'):
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contentLength=headers['Content-Length']
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signedHeaderList.append(f'content-length: {contentLength}')
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else:
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if headers.get('Content-length'):
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contentLength=headers['Content-length']
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signedHeaderList.append(f'content-length: {contentLength}')
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else:
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if debug:
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print('DEBUG: verifyPostHeaders '+signedHeader+' not found in '+str(headers))
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else:
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if headers.get(signedHeader):
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if signedHeader=='date':
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if not verifyRecentSignature(headers[signedHeader]):
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if debug:
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print('DEBUG: verifyPostHeaders date is not recent '+headers[signedHeader])
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return False
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#print('***************************Verify '+signedHeader+': '+headers[signedHeader])
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signedHeaderList.append(
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f'{signedHeader}: {headers[signedHeader]}')
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else:
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signedHeaderCap=signedHeader.capitalize()
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if signedHeaderCap=='Date':
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if not verifyRecentSignature(headers[signedHeaderCap]):
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if debug:
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print('DEBUG: verifyPostHeaders date is not recent '+headers[signedHeader])
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return False
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#print('***************************Verify '+signedHeaderCap+': '+headers[signedHeaderCap])
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if headers.get(signedHeaderCap):
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signedHeaderList.append(
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f'{signedHeader}: {headers[signedHeaderCap]}')
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#print('***********************signedHeaderList: ')
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#pprint(signedHeaderList)
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if debug:
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print('DEBUG: signedHeaderList: '+str(signedHeaderList))
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# Now we have our header data digest
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signedHeaderText = '\n'.join(signedHeaderList)
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#print('***********************Verify: signedHeaderText: '+signedHeaderText)
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headerDigest = SHA256.new(signedHeaderText.encode('ascii'))
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# Get the signature, verify with public key, return result
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signature = base64.b64decode(signatureDict['signature'])
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try:
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pkcs1_15.new(publicKeyPem).verify(headerDigest, signature)
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return True
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except (ValueError, TypeError):
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if debug:
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print('DEBUG: verifyPostHeaders pkcs1_15 verify failure')
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return False
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