#!/usr/bin/env python | |
# | |
# fetch the certificate that the server(s) are providing in PEM form | |
# | |
# args are HOST:PORT [, HOST:PORT...] | |
# | |
# By Bill Janssen. | |
import sys | |
def fetch_server_certificate (host, port): | |
import re, tempfile, os, ssl | |
def subproc(cmd): | |
from subprocess import Popen, PIPE, STDOUT | |
proc = Popen(cmd, stdout=PIPE, stderr=STDOUT, shell=True) | |
status = proc.wait() | |
output = proc.stdout.read() | |
return status, output | |
def strip_to_x509_cert(certfile_contents, outfile=None): | |
m = re.search(r"^([-]+BEGIN CERTIFICATE[-]+[\r]*\n" | |
r".*[\r]*^[-]+END CERTIFICATE[-]+)$", | |
certfile_contents, re.MULTILINE | re.DOTALL) | |
if not m: | |
return None | |
else: | |
tn = tempfile.mktemp() | |
fp = open(tn, "w") | |
fp.write(m.group(1) + "\n") | |
fp.close() | |
try: | |
tn2 = (outfile or tempfile.mktemp()) | |
status, output = subproc(r'openssl x509 -in "%s" -out "%s"' % | |
(tn, tn2)) | |
if status != 0: | |
raise OperationError(status, tsig, output) | |
fp = open(tn2, 'rb') | |
data = fp.read() | |
fp.close() | |
os.unlink(tn2) | |
return data | |
finally: | |
os.unlink(tn) | |
if sys.platform.startswith("win"): | |
tfile = tempfile.mktemp() | |
fp = open(tfile, "w") | |
fp.write("quit\n") | |
fp.close() | |
try: | |
status, output = subproc( | |
'openssl s_client -connect "%s:%s" -showcerts < "%s"' % | |
(host, port, tfile)) | |
finally: | |
os.unlink(tfile) | |
else: | |
status, output = subproc( | |
'openssl s_client -connect "%s:%s" -showcerts < /dev/null' % | |
(host, port)) | |
if status != 0: | |
raise OSError(status) | |
certtext = strip_to_x509_cert(output) | |
if not certtext: | |
raise ValueError("Invalid response received from server at %s:%s" % | |
(host, port)) | |
return certtext | |
if __name__ == "__main__": | |
if len(sys.argv) < 2: | |
sys.stderr.write( | |
"Usage: %s HOSTNAME:PORTNUMBER [, HOSTNAME:PORTNUMBER...]\n" % | |
sys.argv[0]) | |
sys.exit(1) | |
for arg in sys.argv[1:]: | |
host, port = arg.split(":") | |
sys.stdout.write(fetch_server_certificate(host, int(port))) | |
sys.exit(0) |