trimstray / mkchain

Open source tool to help you build a valid SSL certificate chain.

Hi!

I'm a System and Network Administrator. I post my ongoing research at blkcipher.pl.

Some of my blog posts ^[PL]

• Czym jest i jakie znaczenie ma średnie obciążenie systemu?
• TLS: Jaki rozmiar powinien mieć klucz prywatny?
• Co jeśli kill -9 nie działa?
• NGINX: Usprawnienie zamykania procesów roboczych
• Dlaczego pamięć SWAP jest nadal istotna?
• Negocjacja wersji TLS i pakiet szyfrów sygnalizacyjnych

mkchain's Issues

Improvement output when CN is missing.

Next Release: testing
Status: In Progress

The problem is the lack of the CN field for the last certificate in the chain.

How can reproduce the problem?

Properly chain for google.com is:

Certificate chain
 0 s:/C=US/ST=California/L=Mountain View/O=Google Inc/CN=*.google.com
   i:/C=US/O=Google Inc/CN=Google Internet Authority G2
 1 s:/C=US/O=Google Inc/CN=Google Internet Authority G2
   i:/C=US/O=GeoTrust Inc./CN=GeoTrust Global CA
 2 s:/C=US/O=GeoTrust Inc./CN=GeoTrust Global CA
   i:/C=US/O=Equifax/OU=Equifax Secure Certificate Authority

1. Show certificate chain for google.com:

echo | openssl s_client -connect google.com:443 -servername google.com -showcerts

2. Download all certificates (manually)

3. Run sslmerge:

sslmerge -i /tmp/example/ -o /tmp/output.crt                

  	           (ServerCertificate.crt)
  	           (Identity Certificate)
  S:(a18bd28a):(*.google.com)
  I:(c4c7a654):(GoogleInternetAuthorityG2)
  	           (Intermediate1.crt)
  	           (Intermediate Certificate)
  S:(c4c7a654):(GoogleInternetAuthorityG2)
  I:(2c543cd1):(GeoTrustGlobalCA)
  	           (Intermediate2.crt)
  	           (Intermediate Certificate)
  S:(2c543cd1):(GeoTrustGlobalCA)
  I:(578d5c04):()
  	           (RootCertificate.crt)
  	           (Root Certificate)
  S:(578d5c04):()
  I:(578d5c04):()

  Result: chain generated correctly

You will see empty fields for the certificate marked with an identifier 578d5c04.

Check remote certificates (chain).

For example:

mkchain --in https://example.com

Added a root certificate to the certificate chain.

Next Release: testing
Status: In Progress

Added a root certificate to the certificate chain with the --with-root parameter.

Add option to generate OCSP cert chain

Creating correct certificate chains for OCSP is quite confusing - it would be very useful if sslmerge could generate them. As far as I can see it should include the intermediate and root certs, but not the leaf cert, so if a normal chain cert is leaf -> intermediate, the matching OCSP chain should be intermediate -> root.

Since we already have --with-root, this could perhaps be combined with a new --without-leaf option to achieve this.

default _system_ca_path won't work on FreeBSD and change not taken into account

The default value for _system_ca_path set in src/init is not right for FreeBSD. Changing this value with another path is not taken into account because code has hard-coded values:

$ sslmerge -i foobar.crt -o foobar-full.crt find: /etc/ssl/certs/: No such file or directory sed: 1: "$a-----END CERTIFICATE- ...": command a expects \ followed by text [!] bad certificate (maybe broken): foobar.crt

More importantly, upon error, the certificate file used as input is cleared (content erased).

Readlink usage not compatible with macOS

Current use of command readlink in shell script code is not compatible with macOS:

• install fails
• execution fails

sample error upon execution:
readlink: illegal option -- f usage: readlink [-n] [file ...] /usr/local/bin/sslmerge: line 57: ./../src/settings: No such file or directory /usr/local/bin/sslmerge: line 59: ./../src/helpers: No such file or directory /usr/local/bin/sslmerge: line 61: ./../src/__init__: No such file or directory /usr/local/bin/sslmerge: line 66: __main__: command not found /usr/local/bin/sslmerge: line 68: _exit_: command not found

More information about certificate chain on the result.

Next Release: testing
Status: In Progress

More information about certificate chain on the result.

Create dual-stack OCSP chains

Further to #8, I'm very confused as to how to create valid OCSP certificate chains for dual stack (ECC + RSA) certificates. This comes up in things like nginx, where we can say:

ssl_certificate /etc/ssl/example.com.combined.crt;
ssl_certificate_key /etc/ssl/example.com.key;
ssl_certificate /etc/ssl/example.com-ecc.combined.crt;
ssl_certificate_key /etc/ssl/example.com-ecc.key;
ssl_trusted_certificate /etc/ssl/cert-bundle-rsa-ecc.crt;

so we have multiple certificates, but only a single opportunity to specify a trusted cert chain to use for OCSP. I don't know exactly how this should be formatted since it needs to contain 2 or more intermediate -> root chains, i.e. I don't know whether it should contain:

• intermediate1
• root1
• intermediate2
• root2

or

• intermediate1
• intermediate2
• root1
• root2

or, if they need to share a root (some ECC certs are signed using an RSA root):

• intermediate1
• intermediate2
• root

So it would be very useful if sslmerge could help get this right.

(and yes, it is dumb that openssl can't figure out the cert order itself by matching IDs)

FreeBSD: getopt - sslmerge: invalid option -- 'i:o:'

Status: In Progress

./bin/sslmerge -i example/github.com/all/ -o /tmp/chain.crt
sslmerge: invalid option -- 'i:o:'

Get certificate from URI and System CA store.

Next Release: testing
Status: In Progress

Get certificate from URI and System CA store if only Server Certificate is given as a param.