PKCS7 certificates contain trailing blank lines, causing the EST client to fail during PKCS7-to-PEM conversion.

[Chandankr-121]

Actual behavior
EST-SERVER returning the certificates in PKCS#7 format to the est-client signed by CA using openssl_ca_handler having new additional lines at the end of the certificates.Due to these new lines est-client fails to convert these PKCS#7 certificates into pem file.

Expected behavior
EST-SERVER should return certificates to est-client without any additional lines at the end of the certificates so that est-client can convert easily PKCS#7 certificate into pem file.

[Chandankr-121]

Since I don’t have write access to create a pull request, I am documenting the changes here for reference. These are the modifications:

[#2][EST-PROXY][BUGFIX] Remove Blank Lines from PKCS#7 Certificates in est_handler.py

Fix Type: Bug Fix
Root Cause:
     The EST server was returning PKCS#7 certificates with additional blank lines at the end, causing issues
     when the est-client tried to convert the certificates into PEM format.
Solution:
     Need to be fix in est_handler.py to remove the trailing blank lines from the PKCS#7 certificates before
     returning them to the client.

diff --git a/est_proxy/est_handler.py b/est_proxy/est_handler.py
index b868eda..26289a7 100644
--- a/est_proxy/est_handler.py
+++ b/est_proxy/est_handler.py
@@ -171,7 +171,7 @@ class ESTSrvHandler(BaseHTTPRequestHandler):
# remove pkcs7 start end end tags
pkcs7_struc = pkcs7_struc.replace('-----BEGIN PKCS7-----\n', '')
# do not remove CR from end tag as it must be part of the content

•        pkcs7_struc = pkcs7_struc.replace('-----END PKCS7-----', '')
  

•        pkcs7_struc = pkcs7_struc.replace('-----END PKCS7-----', '').rstrip()
     return pkcs7_struc
  

  def _pkcs7_convert(self, ca_certs, pkcs7_clean=True):