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