add log output [minor]

dumptls/cli.py

@@ -1,14 +1,18 @@
 import subprocess
 import click
 import re
+from OpenSSL import crypto
 
-@click.command()
-@click.argument('target_dns')
+@click.command(context_settings=dict(help_option_names=['-h', '--help']))
+@click.argument('target_dns', required=False)
 @click.option('--port', default=443, help='Port to connect to (default is 443).')
 @click.option('--resolve-ip-address', default=None, help='Optional resolve IP address for the connection.')
 @click.option('--output-file', default='cert_chain.pem', help='Output file to save the certificates (default is cert_chain.pem).')
 def download_tls_certs(target_dns, port, resolve_ip_address, output_file):
     """Download TLS certs including intermediate and root CA certs from a target server."""
+    if not target_dns:
+        click.echo(download_tls_certs.get_help(click.Context(download_tls_certs)))
+        return
 
     if resolve_ip_address:
         connect_option = f"{resolve_ip_address}:{port}"
@@ -22,25 +26,22 @@ def download_tls_certs(target_dns, port, resolve_ip_address, output_file):
     result = subprocess.run(openssl_cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True)
 
     # Extract the certificates from the output
-    certs = re.findall(r'-----BEGIN CERTIFICATE-----(.*?)-----END CERTIFICATE-----', result.stdout, re.DOTALL)
+    certs = re.findall(r'(-----BEGIN CERTIFICATE-----(.*?)-----END CERTIFICATE-----)', result.stdout, re.DOTALL)
 
     if certs:
         with open(output_file, 'w') as f:
             for cert in certs:
-                f.write('-----BEGIN CERTIFICATE-----\n')
-                f.write(cert.strip() + '\n')
-                f.write('-----END CERTIFICATE-----\n')
+                f.write(cert[0] + '\n\n')
 
-        print(f"Certificates have been saved to {output_file}")
-
-        # Check the number of certificates
-        cert_count = len(certs)
-        if cert_count <= 1:
-            print("Warning: No intermediate or root CA certificates found.")
-        else:
-            print(f"Total certificates found: {cert_count}")
+        click.echo(f"Certificates have been saved to {output_file}")
+
+        for cert_text in certs:
+            cert_obj = crypto.load_certificate(crypto.FILETYPE_PEM, cert_text[0])
+            common_name = cert_obj.get_subject().CN
+            serial_number = cert_obj.get_serial_number()
+            click.echo(f"Common Name: {common_name}, Serial Number: {serial_number}")
     else:
-        print(f"Failed to retrieve certificates from {target_dns}")
+        click.echo(f"Failed to retrieve certificates from {target_dns}")
 
 if __name__ == '__main__':
     download_tls_certs()