samadhiweb

smalltalk programming for the web



SHA256/512 Password Hashing for Pharo 5

18 February 2017

I've updated my SHA256/512 password hashing library to Pharo 5's FFI and moved it from SS3 to GH.

In the GH repo, C source files are in the src-c directory. Compile with the Makefile there. Move the .so or .dylib file to where the VM can find it.

To load the Smalltalk code, in a Pharo playground:

Metacello new 
  baseline: 'PasswordCrypt'; 
  repository: 'github://PierceNg/PasswordCrypt/src-st'; 
  load.

Run the tests in TestRunner. Provided the Pharo VM can find the shared library, all 12 tests should pass.

This version adds an authentication database that uses in-image persistence, accessed programmatically via the PCAuthenticator uniqueInstance, and a very simple user interface invoked thusly:

PCAuthenticatorUI new openWithSpec

Currently PCAuthenticator hardcodes to SHA256. It should be straightforward to make the hashing algorithm pluggable, including from other shared libraries. Hosting on GH makes it easier for forks and PRs.

NBSQLite3 with SQLcipher

24 December 2015

SQLcipher "is an open source extension to SQLite that provides transparent 256-bit AES encryption of database files." SQLcipher provides the same API as the SQLite Encryption Extension (SEE) by D Richard Hipp, the original developer of SQLite.

I've added SQLcipher/SEE's API to NBSQLite3. By convention, on Unix, SQLcipher produces a shared library named libsqlcipher.so, while the SQLite shared library is named libsqlite3.so. NBSQLite3 switches between the two libraries based on the messages #beSQLcipher and #beSQLite to the NBSQLite3FFI class.

Here's a demonstration code snippet using the keying pragma in SQL:

| dbf db rs row |

Transcript open; clear.	
NBSQLite3FFI beSQLcipher.
dbf := FileReference newTempFilePrefix: 'cipher-' suffix: '.cdb'.

db := NBSQLite3Connection openOn: dbf fullName.
Transcript show: 'Creating an encrypted database with some data.'; cr.
[   db basicExecute: 'pragma key = "test"'.
    db basicExecute: 'create table if not exists x (xk integer primary key, iv integer, tv text);'.
    db beginTransaction.
    [  rs := db execute: 'insert into x values (NULL, ?, ?)' with: #(1 'two') ] ensure: [ rs close ].
    db commitTransaction
] ensure: [ db close ].

db := NBSQLite3Connection openOn: dbf fullName.
Transcript show: 'Opening the encrypted database.'; cr.
[   db basicExecute: 'pragma key = "test"'.
    [   rs := db execute: 'select * from x'.
        row := rs next.
        Transcript show: (row at: 'xk'); cr.
        Transcript show: (row at: 'iv'); cr.
        Transcript show: (row at: 'tv'); cr.
    ] ensure: [ rs close ]
] ensure: [ db close ].

dbf delete.

NBSQLcipherExample class>>examplePragma contains a longer version of the above snippet that includes reopening the encrypted database file without the keying pragma and using the SQLite library.

Tested on Linux Mint. Code updated in Smalltalk Hub. Some refactoring to be expected, because the above snippet using the keying pragma is the only test I've done.

I've placed a copy of libsqlcipher.so here; it is built on my Linux Mint 17.x laptop from the source here, linking in LibreSSL 2.2.4's libcrypto.a statically.

% openssl sha256 libsqlcipher.so
SHA256(libsqlcipher.so)= 441cbc559a4f38a018121c6d86caa0cf0fb2c5b2a57c353cc09a4e048ec8ebe8

% ldd libsqlcipher.so
    linux-gate.so.1 =>  (0xf77da000)
    libdl.so.2 => /lib/i386-linux-gnu/libdl.so.2 (0xf7569000)
    libpthread.so.0 => /lib/i386-linux-gnu/libpthread.so.0 (0xf754d000)
    libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf739e000)
    /lib/ld-linux.so.2 (0xf77dd000)

For good measure, I've also put up a copy of sqlcipher built at the same time. It requires readline.

% openssl sha256 sqlcipher
SHA256(sqlcipher)= 4ccb3cf2064d41675406a55c8404a8877a40541dd9830009f4c0e203468e3d7b

% ldd sqlcipher
    linux-gate.so.1 =>  (0xf770a000)
    libreadline.so.6 => /lib/i386-linux-gnu/libreadline.so.6 (0xf76a7000)
    libdl.so.2 => /lib/i386-linux-gnu/libdl.so.2 (0xf76a2000)
    libpthread.so.0 => /lib/i386-linux-gnu/libpthread.so.0 (0xf7685000)
    libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf74d7000)
    libtinfo.so.5 => /lib/i386-linux-gnu/libtinfo.so.5 (0xf74b5000)
    /lib/ld-linux.so.2 (0xf770d000)

LibreSSL and Pharo/Squeak SSL plugin

22 October 2015

According to its documentation, on Unix, the Pharo VM's SSL plugin, libSqueakSSL.so, links into OpenSSL libraries dynamically. On my 64bit Ubuntu Trusty machine, OpenSSL is provided by the libssl1.0.0:i386 package.

$ ldd libSqueakSSL.so
    linux-gate.so.1 =>  (0xf77a9000)
    libssl.so.1.0.0 => /lib/i386-linux-gnu/libssl.so.1.0.0 (0xf7727000)
    libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf7579000)
    libcrypto.so.1.0.0 -> /lib/i386-linux-gnu/libcrypto.so.1.0.0 (0xf73cb000)
    /lib/ld-linux.so.2 (0xf77a9000)
    libdl.so.2 => /lib/i386-linux-gnu/libdl.so.2 (0xf73c6000)

(By the way, the SSH2 plugin libssh2.so.1.0.1 requires libcrypto too.)

According to packages.ubuntu.com, Trusty's libssl1.0.0 is built from openssl_1.0.1f.orig.tar.gz plus successive upstream patches.

From the OpenBSD developers, LibreSSL is "a version of the TLS/crypto stack forked from OpenSSL in 2014, with goals of modernizing the codebase, improving security, and applying best practice development processes." LibreSSL also comes with libtls, "a new TLS library, designed to make it easier to write foolproof applications".

Let's see how we go about linking libSqueakSSL.so with LibreSSL.

First, download and unpack LibreSSL. Modify the configure script at lines 2287 and 2289 so that LIBCRYPTO_VERSION and LIBSSL_VERSION both say 1:0:0 instead of 35:0:0. Then build LibreSSL:

$ CFLAGS=-m32 LDFLAGS=-m32 ./configure --disable-asm
$ make

I'm building on a 64bit OS, hence "-m32". Without "--disable-asm", the build fails. To get the assembler version, which is recommended for serious usage, either set up a 32bit build environment or muck around with autoconf/configure. I suspect the former is easier. :-)

The output files are $SRC/crypto/.libs/libcrypto.so.1.0.0 and $SRC/ssl/.libs/libssl.so.1.0.0. The shared object files have the "1.0.0" suffix because I modified configure above. Alternatively, I could've played around with autoconf, or built the shared objects with the "35.0.0" suffix and sym/hard-link them for the "1.0.0" versions. TIMTOWTDI.

Next, remove the OpenSSL package:

$ sudo apt-get remove libssl1.0.0:i386
$ ldd libSqueakSSL.so
    linux-gate.so.1 =>  (0xf7718000)
    libssl.so.1.0.0 => not found
    libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf7540000)
    /lib/ld-linux.so.2 (0xf7718000)

Finally, put the LibreSSL shared object files into the right place. Where this right place is depends on your environment. TIMTOWTDI. I choose to put them in the Pharo VM directory with its other plugins, and arrange to start Pharo with LD_LIBRARY_PATH set appropriately. Going by the output of ldd again, the following is required:

$ ln libcrypto.so.1.0.0 libcrypto.so.1

After which:

$ ldd libSqueakSSL.so
    linux-gate.so.1 =>  (0xf7709000)
    libssl.so.1.0.0 => /pkg/pharovm/libssl.so.1.0.0 (0xf7696000)
    libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf74c7000)
    libcrypto.so.1 -> /pkg/pharovm/libcrypto.so.1 (0xf72b8000)
    /lib/ld-linux.so.2 (0xf770a000)

Launch the Pharo 4.0 image and run the Zodiac tests. All tests should pass. Well, except testGetPharoVersion, which looks for a file that apparently no longer exists.

Incidentally, Squeak 5.0-All-in-One's SSL plugin appears to have linked its crypto/SSL libraries in statically, so the only way to upgrade is to build a new plugin.

$ ldd SqueakSSL
    linux-gate.so.1 =>  (0xf7736000)
    libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xf7310000)
    /lib/ld-linux.so.2 (0xf7737000)

One Time Passwords

26 March 2015

I bought a Yubikey device and am going to write a Pharo library for it. Meanwhile, I discovered that Richard Prinz has an implementation of RFC 6536 Time-based One Time Passwords for Pharo.

SHA256/512 Password Hashing for Pharo

17 November 2013

Recently, Adobe was hacked, resulting in, among other breakages, the loss of 130 million passwords. It was revealed that the passwords were encrypted using ECB, electronic cookbook mode, which is a rather poor way of securing passwords.

The MacRumors forum site was also hacked recently. The site runs the vBulletin forumware, which protects passwords using md5crypt.

md5crypt is a password hashing scheme devised by Poul-Henning Kamp in 1995. The hashed password takes the format $1$<salt>$<password-hash>. The hash is designed to be expensive to compute, to slow down attacks. In 2012, Poul-Henning announced that md5crypt was no longer considered safe, in view of advances in computing power.

sha-crypt, from Ulrich Depper, is a public domain implementation of SHA-256/512-based password hashing, which works similarly to md5crypt, using SHA-256/512 and allowing an arbitrary number of rounds through the hashing algorithm.

The following commands build and run sha(256|512)crypt.c as self-test programs:

$ cc -DTEST -std=c99 -m32 sha256crypt.c
$ ./a.out
all tests OK
$ cc -DTEST -std=c99 -m32 sha512crypt.c
$ ./a.out
all tests OK

Next, build shared library:

$ cc -std=c99 -m32 -fPIC -c sha256crypt.c
$ cc -std=c99 -m32 -fPIC -c sha512crypt.c
linux$ cc -m32 -shared -o libshacrypt.so *.o
osx$ cc -m32 -shared -o libshacrypt.dylib *.o

Move the .so or .dylib file to where your plugins are.

PCPasswordCrypt is a Smalltalk interface to libshacrypt using NativeBoost. It is very simple to use:

PCPasswordCrypt sha256Crypt: 'Hello world!' withSalt: 'saltstring'.
'$5$saltstring$5B8vYYiY.CVt1RlTTf8KbXBH3hsxY/GNooZaBBGWEc5'

Tested on OSX (Mountain Lion) and Linux (Mint 14). The C programs work on FreeBSD, but my self-built FreeBSD Cog VM doesn't have NativeBoost.

The C programs are found here. Once I figure out how, I'll put them on GitHub. PCPasswordCrypt is published on SqueakSource3.

Cryptographic Libraries for Pharo and Squeak

13 November 2013

NaCl (pronounced "salt") is a new, easy to use high-speed software library for network communication, encryption, decryption, signatures, etc. It uses elliptic curve cryptography. libsodium is a portable fork of NaCl. Crypto-Nacl is a Pharo/Squeak interface to libsodium. It uses FFI. As is, the library should be named liblibsodium.dylib when used with Crypto-Nacl on OSX.

SqueakSSL is a plugin to the platform-native SSL/TLS facility. The plugin is bundled with the Cog VM. Zodiac is an open source, cross-Smalltalk implementation of regular and secure socket streams. Zodiac uses SqueakSSL. Webclient also uses SqueakSSL to support HTTPS.

The Cryptography package has been around for a while. It now lives on SmalltalkHub. It has plugins for DES, DSA, MD5 and SHA256. At this time, this package doesn't look viable for real-world use.