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"""PGP/MIME interface for Slime.
Parts of this module is based on the algorithms in pgpExec.tcl in
Exmh 2.0gamma.
"""
from slime_abstract import *
from slime_mh import *
from slime_unix import *
from ui_config import config
import slime_send, helpers
import tempfile, regex, mimetools, os, FCNTL
# Exception names for results of PGP stuff
SecretMissing = "slime_pgp.SecretMissing"
PublicMissing = "slime_pgp.PublicMissing"
GoodUntrustedSignature = "slime_pgp.GoodUntrustedSignature"
BadUntrustedSignature = "slime_pgp.BadUntrustedSignature"
BadTrustedSignature = "slime_pgp.BadTrustedSignature"
OtherResult = "slime_pgp.OtherResult"
# Regular expressions for interpreting the PGP results
secret_missing_pat = \
regex.compile("This.*do not have the secret key.*file", regex.casefold)
public_missing_pat = \
regex.compile("Can't.*can't check signature integrity", regex.casefold)
good_signature_pat = \
regex.compile("Good signature", regex.casefold)
confidence_pat = \
regex.compile("WARNING:.*confidence", regex.casefold)
doesnt_match_pat = \
regex.compile("WARNING:.*doesn't match", regex.casefold)
def interpret_pgp(exit_code, stdout, stderr):
"""Interpret the output of PGP, raise exception for errors."""
tuple = (exit_code, stdout, stderr)
if secret_missing_pat.search(stdout) >= 0:
raise SecretMissing, tuple
elif public_missing_pat.search(stdout) >= 0:
raise PublicMissing, tuple
elif good_signature_pat.search(stdout) >= 0:
if confidence_pat.search(stdout) >= 0:
raise GoodUntrustedSignature, tuple
else:
return # Yay! It's OK! Way to go, man!
elif doesnt_match_pat.search(stdout) >= 0:
if confidence_pat.search(stdout) >= 0:
raise BadUntrustedSignature, tuple
else:
raise BadTrustedSignature, tuple
else:
raise OtherResult, tuple
def write_to_named_file(filename, msg):
helpers.write_text_to_named_file(filename,
msg.getheadertext() + "\n" + msg.getbodytext()[:-1])
# XXX note that the [:-1] part is a kludge -- exmh
# creates an extra newline or something
def check_signature(msg):
"""Check signature of a PGP/MIME message, raise exception for errors."""
if msg.gettype() != "multipart/signed" or \
not "protocol" in msg.getparamnames() or \
msg.getparam("protocol") != "application/pgp-signature" or \
not "micalg" in msg.getparamnames() or \
msg.getparam("micalg") != "pgp-md5":
return None
parts = msg.getbodyparts()
msgtxt = tempfile.mktemp()
msgsig = tempfile.mktemp()
write_to_named_file(msgtxt, parts[0])
write_to_named_file(msgsig, parts[1])
exit_code, stdout, stderr = \
helpers.run_pgp(config["pgp-path"], "", "", [], [msgsig, msgtxt])
os.remove(msgtxt)
os.remove(msgsig)
interpret_pgp(exit_code, stdout, stderr)
def filter_content_headers(headername):
headername = string.lower(headername)
return not headername in ["content-type", "content-transfer-encoding"]
def make_signature(msg, username, password):
"""Return string with text of signed message."""
body_type = msg["content-type"]
body_xfer = msg["content-transfer-encoding"]
if not body_type or body_type == "text/plain":
charset = slime_send.deduce_charset(msg.getbodytext())
body_type = "text/plain; charset=%s" % charset
if charset == "us-ascii":
body_xfer = "7bit"
else:
body_xfer = "8bit"
msg_headers = msg.getheadertext(filter_content_headers)
msg_body = msg.getbodytext(decode=0)
boundary = mimetools.choose_boundary()
msg_type = 'multipart/signed; boundary=%s;\n' + \
' micalg=pgp-md5; protocol="application/pgp-signature"'
msg_type = msg_type % boundary
part1_headers = "Content-Type: %s\nContent-Transfer-Encoding: %s\n" % \
(body_type, body_xfer)
part1 = part1_headers + "\n" + msg_body
exit_code, stdout, stderr = \
helpers.run_pgp(config["pgp-path"], username, password,
["-sbatf"], [], stdin=part1)
if exit_code != 0:
raise OtherResult, (exit_code, stdout, stderr)
part2_headers = "Content-Type: application/pgp\n"
part2 = part2_headers + "\n" + stdout
return "%sContent-Type: %s\n\n--%s\n%s\n--%s\n%s\n--%s--\n" % \
(msg_headers, msg_type, boundary, part1,
boundary, part2, boundary)
def test_check_signature():
mhroot = mh_top_folder()
mhroot.open()
mhroot.rescan_subfolders()
for sub in mhroot.list_all_subfolders():
if sub.get_nice_name() == "sent-mail":
sub.open()
sub.rescan_messages()
list = sub.list_all_messages()[:1]
if list:
msg = list[0]
result = check_signature(msg)
print "Check result:"
print result
sub.close()
mhroot.close()
def test_make_signature():
import sys
mhroot = mh_top_folder()
mhroot.open()
mhroot.rescan_subfolders()
for sub in mhroot.list_all_subfolders():
if sub.get_nice_name() == "drafts":
sub.open()
sub.rescan_messages()
list = sub.list_all_messages()[:1]
if list:
msg = list[0]
print "Enter username:"
username = sys.stdin.readline()[:-1]
print "Enter password:"
password = sys.stdin.readline()[:-1]
result = make_signature(msg, username, password)
print result
sub.close()
mhroot.close()
if __name__ == "__main__":
test_check_signature()
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