# Author: Trevor Perrin
# See the LICENSE file for legal information regarding use of this file.
from .compat import *
import binascii
#This code is shared with tackpy (somewhat), so I'd rather make minimal
#changes, and preserve the use of a2b_base64 throughout.
[docs]
def dePem(s, name):
"""Decode a PEM string into a bytearray of its payload.
The input must contain an appropriate PEM prefix and postfix
based on the input name string, e.g. for name="CERTIFICATE"::
-----BEGIN CERTIFICATE-----
MIIBXDCCAUSgAwIBAgIBADANBgkqhkiG9w0BAQUFADAPMQ0wCwYDVQQDEwRUQUNL
...
KoZIhvcNAQEFBQADAwA5kw==
-----END CERTIFICATE-----
The first such PEM block in the input will be found, and its
payload will be base64 decoded and returned.
"""
prefix = "-----BEGIN %s-----" % name
postfix = "-----END %s-----" % name
start = s.find(prefix)
if start == -1:
raise SyntaxError("Missing PEM prefix")
end = s.find(postfix, start+len(prefix))
if end == -1:
raise SyntaxError("Missing PEM postfix")
s = s[start+len("-----BEGIN %s-----" % name) : end]
retBytes = a2b_base64(s) # May raise SyntaxError
return retBytes
[docs]
def dePemList(s, name):
"""Decode a sequence of PEM blocks into a list of bytearrays.
The input must contain any number of PEM blocks, each with the appropriate
PEM prefix and postfix based on the input name string, e.g. for
name="TACK BREAK SIG". Arbitrary text can appear between and before and
after the PEM blocks. For example::
Created by TACK.py 0.9.3 Created at 2012-02-01T00:30:10Z
-----BEGIN TACK BREAK SIG-----
ATKhrz5C6JHJW8BF5fLVrnQss6JnWVyEaC0p89LNhKPswvcC9/s6+vWLd9snYTUv
YMEBdw69PUP8JB4AdqA3K6Ap0Fgd9SSTOECeAKOUAym8zcYaXUwpk0+WuPYa7Zmm
SkbOlK4ywqt+amhWbg9txSGUwFO5tWUHT3QrnRlE/e3PeNFXLx5Bckg=
-----END TACK BREAK SIG-----
Created by TACK.py 0.9.3 Created at 2012-02-01T00:30:11Z
-----BEGIN TACK BREAK SIG-----
ATKhrz5C6JHJW8BF5fLVrnQss6JnWVyEaC0p89LNhKPswvcC9/s6+vWLd9snYTUv
YMEBdw69PUP8JB4AdqA3K6BVCWfcjN36lx6JwxmZQncS6sww7DecFO/qjSePCxwM
+kdDqX/9/183nmjx6bf0ewhPXkA0nVXsDYZaydN8rJU1GaMlnjcIYxY=
-----END TACK BREAK SIG-----
All such PEM blocks will be found, decoded, and return in an ordered list
of bytearrays, which may have zero elements if not PEM blocks are found.
"""
bList = []
prefix = "-----BEGIN %s-----" % name
postfix = "-----END %s-----" % name
while 1:
start = s.find(prefix)
if start == -1:
return bList
end = s.find(postfix, start+len(prefix))
if end == -1:
raise SyntaxError("Missing PEM postfix")
s2 = s[start+len(prefix) : end]
retBytes = a2b_base64(s2) # May raise SyntaxError
bList.append(retBytes)
s = s[end+len(postfix) : ]
[docs]
def pem(b, name):
"""Encode a payload bytearray into a PEM string.
The input will be base64 encoded, then wrapped in a PEM prefix/postfix
based on the name string, e.g. for name="CERTIFICATE"::
-----BEGIN CERTIFICATE-----
MIIBXDCCAUSgAwIBAgIBADANBgkqhkiG9w0BAQUFADAPMQ0wCwYDVQQDEwRUQUNL
...
KoZIhvcNAQEFBQADAwA5kw==
-----END CERTIFICATE-----
"""
s1 = b2a_base64(b)[:-1] # remove terminating \n
s2 = ""
while s1:
s2 += s1[:64] + "\n"
s1 = s1[64:]
s = ("-----BEGIN %s-----\n" % name) + s2 + \
("-----END %s-----\n" % name)
return s
[docs]
def pemSniff(inStr, name):
searchStr = "-----BEGIN %s-----" % name
return searchStr in inStr