Building and using Cyrus SASL on Mac OS X

The Cyrus SASL v2 distribution now supports Mac OS X, including applications written to Apple’s Carbon and Cocoa interfaces, as well as the standard Unix-like API. It includes the following components:

  • A port of the Unix SASL library, which lives in /usr/local/lib/libsasl2.dylib (or similar) and with plugins in /usr/lib/sasl (which should be a symlink to /usr/local/lib/sasl).

  • A framework which lives in /Library/Frameworks/SASL2.framework, and allows the use of the -framework option to Apple’s ld, or linking with the framework in Project Builder. This framework is in fact a wrapper for a symlink to /usr/local/lib/libsasl2.dylib with the necessary information to recognize it as a framework. This is what we expect many Cocoa and Carbon Mach-O applications will want to use, and the framework is required for CFBundle to work, which is used by the CFM glue library.

  • A CFM glue library (/Library/CFMSupport/SASL2GlueCFM) which can be linked in by Carbon CFM applications, that uses CFBundle to bind the framework and thus load the Unix-level library. It automatically loads the important functions at sasl_client_init or sasl_server_init time; it also automatically makes sure memory allocation works if you’re using the metrowerks malloc; if you’re not, sasl_set_alloc works as usual.

  • A Carbon port of the existing CFM library for Mac OS 9. Note that this could probably be modified fairly easily to work on OS X, but there’s not much point. The CFM glue layer to the Unix library supports many more functions, including the entire server API; also, the Unix implementation is mostly independent of Kerberos implementation, while the Mac OS 9 Carbon port specifically requires MIT Kerberos for Macintosh 3.5 or later in order to get Kerberos support. The Mac OS 9 code implements only the client API, but this is mostly what is wanted from SASL on OS 9 anyway.

If you are building a Carbon CFM application and intend it to run on both OS 9 and OS X, you should link against the OS 9 Carbon SASL library, since it exports fewer APIs (client side only, specifically) than the OS X CFM glue. Your application should work seamlessly with both libraries if you do this, despite the different implementations underneath.

If you need a Carbon CFM application to support server-side SASL functionality, you need to link against the SASL2GlueCFM library, but be aware that your application will not run on OS 9.

Compiling and Using the Unix library

The Unix library is mostly ready to build on Mac OS X, but it does depend on the dlcompat package in order to load its plugins. dlcompat-20010505 is a relatively simple version known to work with SASL; it is provided with the distribution in a tarball. You should make and make install the dlcompat library (which probably goes into /usr/local/lib/libdl.dylib) before attempting to ./configure the SASL distribution itself. SASL will then pretend it’s a real Unix libdl, and link against it.

Since there are, at this point, newer and far more complex versions of dlcompat, you may prefer to use those instead if other software requires their functionality. The dlcompat homepage is located on the OpenDarwin site. Many users may want to install the /sw tree from the Fink project to get this, as well as possibly newer autotools and other software.

As of version 2.1.16, SASL uses and requires a recent version of GNU autotools (autoconf, automake, and libtool) to build its configuration scripts. If you are building from GIT, you will need to have the autotools installed on your system. The version included with all releases of the developer tools for OS X 10.2.x is too old for this; if you aren’t using OS X 10.3 or later, you should upgrade to more recent patchlevels of these tools. The easiest way to do this is to install the Fink environment and then apt-get install autoconf2.5 automake1.7 libtool14.

Recent versions of SASL ship with Kerberos v4 disabled by default. If you need Kerberos v4 for some reason, and you are using MIT Kerberos for Macintosh 4.0 or later, you should ./configure with the added options "--enable-krb4=/usr --without-openssl --disable-digest" so that it finds the correct location for the header files, and does not use OpenSSL or build anything that depends on it (such as the digest-md5 plugin), since OpenSSL provides its own DES routines which do not work with Kerberos v4.

Warning

Please read the “Known Problems” section at the end of this document for more information on this issue.

You must be root to make install, since /usr/local is only modifiable by root. You need not enable the root account using NetInfo; the recommended (but underdocumented) method is to use sudo -s from the Terminal window when you are logged into an administrator’s account, and enter the password for that account. When building on Mac OS X, make install will automatically add the framework to /Library/Frameworks.

This does not build the CFM glue library. Building the CFM glue library requires Metrowerks CodeWarrior Pro 6 or later (tested with 6), and the files necessary to build it are in the mac/osx_cfm_glue folder.

Changes to the Unix library to make it work on OS X

This is provided for reference purposes only. The build system will automatically take care of all of these issues when building on Darwin or Mac OS X.

  • The random code supports the preferred way to generate random numbers in Darwin. (In SASL v2, it does this on all unix-like platforms that lack jrand48). Note that Mac OS X “Jaguar”, version 10.2, now has the standard jrand48 function, and that SASL will use this instead of the previous workaround.

  • Symbols which are dlopened have an underscore prefixed. (This behavior is detected by configure in SASL v2.)

  • Plugins are linked with the -module option to libtool, which causes the -bundle option to be supplied to Apple’s ld. (This is done on all platforms in SASL v2.)

  • The MD5 symbols are renamed to avoid library conflicts. This allows proper compilations against Heimdal and MIT’s unix kerberos distribution, and prevents crashes when linked against MIT Kerberos for Macintosh (which also duplicates the symbols, but in a different way). Note that the MD5 symbols have local names on all platforms with SASL v2; this was only different in SASL v1.

  • MIT Kerberos for Macintosh 4.0 and later are fully supported. This was accomplished by using krb_get_err_text if available and checking for additional names for the krb4 libraries.

Changes to the Mac OS 9 projects to support Carbon

Warning

Please read these notes before you attempt to build SASL for OS 9 Carbon!

  • Important! You must make sure that all files have their correct HFS filetype before starting to build this code! In particular, all source and text files must be of type 'TEXT', which is not the default if you use the Mac OS X GIT client to check out the projects. If you run into this problem, you may want to use a utility such as FileTyper to recursively change the type on all files. CodeWarrior is less picky about the projects’ filetypes, but setting them to filetype 'MMPr', creator code 'CWIE' may be helpful in opening the projects from the Finder. Users on Mac OS X familiar with the Unix find command should be able to rig /Developer/Tools/SetFile to do this job as well.

  • Many of the important projects (for libdes, libsasl, build_plugins, and the sample client sc_shlb) have Carbon versions.

  • Plugins are loaded from a Carbon subfolder of the SASL v2 folder in the Extensions folder. Plugins directly in the SASL v2 folder are considered to be for the Classic libraries.

  • Note that when using the build_plugins project, you must generate the plugin init files using the makeinit.sh script in the plugins directory. The easiest way to do this is to run the script from a Unix shell, such as Mac OS X. You must then fix the filetypes of the generated source files (see above).

  • There is a new folder in CommonKClient called mac_kclient3 which contains code compatible with MIT’s new KClient 3.0 API. This folder must be in your CodeWarrior access paths, the old mac_kclient folder must not, and it must precede the project’s main folder.

  • The kerberos4 plugin uses this new code. The kerberos4 plugin also statically links the Carbon libdes, and no other part of Carbon SASL uses libdes directly. Your application should **not* link against* libdes.shlb under Carbon! (It causes problems due to DES symbols also existing in the MIT Kerberos library, which loads first.)

  • To build the projects, you should have the MIT Kerberos for Macintosh 3.5 installation disk images mounted, since the access paths include the absolute paths to the library directories from that image. It’s easier than you having to find the paths yourself, and smaller than having to distribute the libraries with SASL.

Known Problems

  • The Kerberos v4 headers bundled with Mac OS X (and Kerberos for Macintosh) are not compatible with OS X’s OpenSSL headers. (Kerberos v4 support is disabled by default.) If you actually need krb4 support, the easiest solution is to build without using OpenSSL’s libcrypto. To do this, specify the --without-openssl option to configure. As of version 2.1.18, this automatically disables using libcrypto for DES as well. You will probably also need to specify --disable-digest since the digestmd5 plugin does not build against Kerberos v4’s DES headers or library. Note that this disables several features (DIGEST-MD5, NTLM, OTP, PASSDSS, SCRAM, SRP) which require OpenSSL. If both Kerberos v4 and functionality that requires OpenSSL are needed, it is possible to build the Kerberos v4 plugin against the correct K4 DES libraries, and everything else against OpenSSL; however, we do not support that configuration.

  • Versions of Cyrus SASL prior to 2.1.14 with support for Carbon CFM applications on Mac OS X have a known bug involving the CFM glue code (in mac/osx_cfm_glue). If sasl_done is called to unload the SASL library, and then one of the initialization functions (such as sasl_client_init) is called to reinitialize it from the same process, the application will crash. A fix for one obvious cause of this problem is included in 2.1.14; however, as of this writing, it has not been tested. It is possible that other bugs in Cyrus SASL, or deficiencies in Apple’s libraries, will make this fix insufficient to resolve this issue.