Simple periodic task to sync OSX Keychain certs to Homebrew installed OpenSSL & LibreSSL
Objective-C Shell Makefile
Latest commit 1039bec Oct 28, 2016 @raggi security: do not export untrusted certs
The prior implementation relied on subcommands of `security(1)` that
all output certificates marked as "untrusted" in keychains.

As there appears to be no native command line application in OSX that
enables differentiation of trusted and untrusted certificates, some
objective c dependencies are now included. The code used requires El
Capitan or newer, and depends on XCode.

The security report was delivered by Eric Hodel. Thank you for your
dilligence, excellent report format, and perfect reporting practice.

The code used to implement the binary introduced by this change was
adapted from code in the Go programming language, and is copyright
"Copyright 2011 The Go Authors" and is covered by the Go LICENSE.

Apologies, but due to lack of time and effort, and also apparent usage,
I also chose not to carry forward the two --skip-* options that
previously allowed users to skip login and/or system certificates.

README.md

osx-ca-certs (previously openssl-osx-ca (and libressl-osx-ca))

A simple tool and script intended to be run periodically by launchd(8) to sync an openssl style CA pem with the certificates found in the OSX Keychain(s).

The original name is now a misnomer, as the software will manage certificate bundles for both openssl and libressl installed under Homebrew.

The Makefile contains a target called osx-ca-certs that acts a lot like security export -t certs -p, except that it does not dump certificates that are marked as untrusted as the latter does.

The keychains exported to the CA bundle by default are:

  • System.keychain
  • SystemRootCertificates.keychain
  • login.keychain (if run as a user)

The installed CA pem file will be made available through the default X.509 store path, commonly /usr/local/etc/openssl/cert.pem.

Installation

  • To install via homebrew:

       brew tap raggi/ale
       brew install openssl-osx-ca
       brew services start openssl-osx-ca
  • To install standalone:

       make install
  • To set the frequency, set the value of FREQUENCY when installing, defaults to 3600, one hour. The value of FREQUENCY must be a value in seconds.

       make install FREQUENCY=3600
  • Other variables from the Makefile can be overridden, take a look at the head of the Makefile for more information.

Intended use cases

  • Ruby 2.0.0+
  • LibreSSL users
  • OpenSSL users
  • Other brew / manually installed things that link a non-Apple TLS implementations

Known limitations & Notes

  • Only supports El Capitan and above.
  • Syncs are by default perfomed once per hour.
  • Syncs may not be sufficiently atomic. There is a small possiblity of race conditions that could cause openssl programs to fail. The sync time is very very short, so in practice this is unlikely.
  • OSX CA bundles are not always particularly up to date, for example in August 2016, they contained 17 expired certificates and several that Mozilla have chosen to remove, either for technical or audit reasons.
  • Installation as root is generally not required, and may require some extra changes to the Makefile.