Add support for RSA decryption using PKCS #11 tokens

Add support for loading RSA private key files from PKCS #11 tokens,
identified by PKCS #11 URIs. Add a new 'pkcs11_libs' UAT which can
dynamically load PKCS #11 provider libraries that are not found by
p11-kit.

The configuration GUI will need additional code to discover available
PKCS #11 tokens and will be added later.

This feature requires GnuTLS 3.4 with PKCS #11 support, so Windows,
macOS via Homebrew, Ubuntu 16.04, Debian Stretch. Not supported: RHEL7.
Currently macOS via official packages disables PKCS #11 support, so that
will also not work.

Change-Id: I20646bfd69c6bd13c8c2d27cb65c164a4b0b7a66
Reviewed-on: https://code.wireshark.org/review/30855
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot
Reviewed-by: Peter Wu <peter@lekensteyn.nl>

3 files changed, 142 insertions, 0 deletions

diff --git a/test/fixtures_ws.py b/test/fixtures_ws.py
index cfadaf0ab8..6fd5d791d1 100644
--- a/test/fixtures_ws.py
+++ b/test/fixtures_ws.py
@@ -145,12 +145,14 @@ def features(cmd_tshark, make_env):
         tshark_v = ''
     gcry_m = re.search(r'with +Gcrypt +([0-9]+\.[0-9]+)', tshark_v)
     return types.SimpleNamespace(
+        have_x64='Compiled (64-bit)' in tshark_v,
         have_lua='with Lua' in tshark_v,
         have_nghttp2='with nghttp2' in tshark_v,
         have_kerberos='with MIT Kerberos' in tshark_v or 'with Heimdal Kerberos' in tshark_v,
         have_libgcrypt16=gcry_m and float(gcry_m.group(1)) >= 1.6,
         have_libgcrypt17=gcry_m and float(gcry_m.group(1)) >= 1.7,
         have_gnutls='with GnuTLS' in tshark_v,
+        have_pkcs11='and PKCS #11 support' in tshark_v,
     )
 
 
diff --git a/test/keys/rsa-p-lt-q.p8 b/test/keys/rsa-p-lt-q.p8
new file mode 100644
index 0000000000..d9fca7ee08
--- /dev/null
+++ b/test/keys/rsa-p-lt-q.p8
@@ -0,0 +1,16 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----
diff --git a/test/suite_decryption.py b/test/suite_decryption.py
index aad2b2dde0..1cbdaf33bb 100644
--- a/test/suite_decryption.py
+++ b/test/suite_decryption.py
@@ -10,7 +10,12 @@
 '''Decryption tests'''
 
 import os.path
+import shutil
+import subprocess
 import subprocesstest
+import sys
+import sysconfig
+import types
 import unittest
 import fixtures
 
@@ -862,3 +867,122 @@ class case_decrypt_knxip(subprocesstest.SubprocessTestCase):
         self.assertTrue(self.grepOutput('^IA 1[.]1[.]4 SeqNr 12345$'))
         self.assertTrue(self.grepOutput('^IA 2[.]1[.]0 key B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 BA BB BC BD BE BF$'))
         self.assertTrue(self.grepOutput('^IA 2[.]1[.]0 SeqNr 1234$'))
+
+
+@fixtures.fixture(scope='session')
+def softhsm_paths(features):
+    if sys.platform == 'win32':
+        search_path = os.getenv('PATH') + r';C:\SoftHSM2\bin'
+    else:
+        search_path = None
+    softhsm_tool = shutil.which('softhsm2-util', path=search_path)
+    if not softhsm_tool:
+        # Note: do not fallback to SoftHSMv1. While available on Ubuntu 14.04
+        # (and 16.04), it is built with botan < 1.11.10 which causes a crash due
+        # to a conflict with the GMP library that is also used by GnuTLS/nettle.
+        # See https://github.com/randombit/botan/issues/1090
+        fixtures.skip('SoftHSM is not found')
+    # Find provider library path.
+    bindir = os.path.dirname(softhsm_tool)
+    libdir = os.path.join(os.path.dirname(bindir), 'lib')
+    if sys.platform == 'win32':
+        libdirs = [libdir, bindir]
+        if features.have_x64:
+            name = 'softhsm2-x64.dll'
+        else:
+            name = 'softhsm2.dll'
+    else:
+        # Debian/Ubuntu-specific paths
+        madir = sysconfig.get_config_var('multiarchsubdir')
+        libdir64_sub = os.path.join(libdir + '64', 'softhsm')
+        libdir_sub = os.path.join(libdir, 'softhsm')
+        libdirs = [os.path.join(libdir + madir, 'softhsm')] if madir else []
+        libdirs += [libdir_sub, libdir64_sub]
+        name = 'libsofthsm2.so'
+    for libdir in libdirs:
+        provider = os.path.join(libdir, name)
+        if os.path.exists(provider):
+            break
+    else:
+        # Even if p11-kit can automatically locate it, do not rely on it.
+        fixtures.skip('SoftHSM provider library not detected')
+    # Now check whether the import tool is usable. SoftHSM < 2.3.0 did not
+    # set CKA_DECRYPT when using softhsm2-tool --import and therefore cannot be
+    # used to import keys for decryption. Use GnuTLS p11tool as workaround.
+    softhsm_version = subprocess.check_output([softhsm_tool, '--version'],
+            universal_newlines=True).strip()
+    use_p11tool = softhsm_version in ('2.0.0', '2.1.0', '2.2.0')
+    if use_p11tool and not shutil.which('p11tool'):
+        fixtures.skip('SoftHSM available, but GnuTLS p11tool is unavailable')
+    return use_p11tool, softhsm_tool, provider
+
+
+@fixtures.fixture
+def softhsm(softhsm_paths, home_path, base_env):
+    '''Creates a temporary SoftHSM token store (and set it in the environment),
+    returns a function to populate that token store and the path to the PKCS #11
+    provider library.'''
+    use_p11tool, softhsm_tool, provider = softhsm_paths
+    conf_path = os.path.join(home_path, 'softhsm-test.conf')
+    db_path = os.path.join(home_path, 'softhsm-test-tokens')
+    os.makedirs(db_path)
+    with open(conf_path, 'w') as f:
+        f.write('directories.tokendir = %s\n' % db_path)
+        f.write('objectstore.backend = file\n')
+        # Avoid syslog spam
+        f.write('log.level = ERROR\n')
+    base_env['SOFTHSM2_CONF'] = conf_path
+
+    tool_env = base_env.copy()
+    if sys.platform == 'win32':
+        # Ensure that softhsm2-util can find the library.
+        tool_env['PATH'] += ';%s' % os.path.dirname(provider)
+
+    # Initialize tokens store.
+    token_name = 'Wireshark-Test-Tokens'
+    pin = 'Secret'
+    subprocess.check_call([softhsm_tool, '--init-token', '--slot', '0',
+        '--label', token_name, '--so-pin', 'Supersecret', '--pin', pin],
+        env=tool_env)
+    if use_p11tool:
+        tool_env['GNUTLS_PIN'] = pin
+
+    # Arbitrary IDs and labels.
+    ids = iter(range(0xab12, 0xffff))
+    def import_key(keyfile):
+        '''Returns a PKCS #11 URI to identify the imported key.'''
+        label = os.path.basename(keyfile)
+        obj_id = '%x' % next(ids)
+        if not use_p11tool:
+            tool_args = [softhsm_tool, '--import', keyfile, '--label', label,
+                    '--id', obj_id, '--pin', pin, '--token', token_name]
+        else:
+            # Fallback for SoftHSM < 2.3.0
+            tool_args = ['p11tool', '--provider', provider, '--batch',
+                    '--login', '--write', 'pkcs11:token=%s' % token_name,
+                    '--load-privkey', keyfile, '--label', label, '--id', obj_id]
+        subprocess.check_call(tool_args, env=tool_env)
+        id_str = '%{}{}%{}{}'.format(*obj_id)
+        return 'pkcs11:token=%s;id=%s;type=private' % (token_name, id_str)
+
+    return types.SimpleNamespace(import_key=import_key, provider=provider, pin=pin)
+
+
+@fixtures.mark_usefixtures('test_env')
+@fixtures.uses_fixtures
+class case_decrypt_pkcs11(subprocesstest.SubprocessTestCase):
+    def test_tls_pkcs11(self, cmd_tshark, dirs, capture_file, features, softhsm):
+        '''Check that a RSA key in a PKCS #11 token enables decryption.'''
+        if not features.have_pkcs11:
+            self.skipTest('Requires GnuTLS with PKCS #11 support.')
+        key_file = os.path.join(dirs.key_dir, 'rsa-p-lt-q.p8')
+        key_uri = softhsm.import_key(key_file)
+        proc = self.assertRun((cmd_tshark,
+                '-r', capture_file('rsa-p-lt-q.pcap'),
+                '-o', 'uat:pkcs11_libs:"{}"'.format(softhsm.provider.replace('\\', '\\x5c')),
+                '-o', 'uat:rsa_keys:"{}","{}"'.format(key_uri, softhsm.pin),
+                '-Tfields',
+                '-e', 'http.request.uri',
+                '-Y', 'http',
+            ))
+        self.assertIn('/', proc.stdout_str)