New module utils openssh.certificate (#246)

* Initial commit

* Adding informational comments

* Adding changelog fragment

* Fixing CRLF changelog fragment

* Refactoring public number parsing and added chaining for writer methods

* Adding more descriptive error for invalid certificate data

* Fixing signature data parsing

* Correcting ed25519 signature type to binary

* Applying initial review suggestions and fixing option-list writer

* Applying review suggestions

* Making OpensshWriter private

tests/unit/plugins/module_utils/openssh/test_utils.py

@@ -0,0 +1,149 @@
+# -*- coding: utf-8 -*-
+
+# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
+
+from __future__ import absolute_import, division, print_function
+__metaclass__ = type
+
+import pytest
+
+from ansible_collections.community.crypto.plugins.module_utils.openssh.utils import (
+    parse_openssh_version,
+    OpensshParser,
+    _OpensshWriter
+)
+
+SSH_VERSION_STRING = "OpenSSH_7.9p1, OpenSSL 1.1.0i-fips  14 Aug 2018"
+SSH_VERSION_NUMBER = "7.9"
+
+VALID_BOOLEAN = [
+    True,
+    False
+]
+INVALID_BOOLEAN = [
+    0x02
+]
+VALID_UINT32 = [
+    0x00,
+    0x01,
+    0x01234567,
+    0xFFFFFFFF,
+]
+INVALID_UINT32 = [
+    0xFFFFFFFFF,
+    -1,
+]
+VALID_UINT64 = [
+    0x00,
+    0x01,
+    0x0123456789ABCDEF,
+    0xFFFFFFFFFFFFFFFF,
+]
+INVALID_UINT64 = [
+    0xFFFFFFFFFFFFFFFFF,
+    -1,
+]
+VALID_STRING = [
+    b'test string',
+]
+INVALID_STRING = [
+    [],
+]
+# See https://datatracker.ietf.org/doc/html/rfc4251#section-5 for examples source
+VALID_MPINT = [
+    0x00,
+    0x9a378f9b2e332a7,
+    0x80,
+    -0x1234,
+    -0xdeadbeef,
+    # Additional large int test
+    0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF,
+]
+INVALID_MPINT = [
+    [],
+]
+
+
+def test_parse_openssh_version():
+    assert parse_openssh_version(SSH_VERSION_STRING) == SSH_VERSION_NUMBER
+
+
+@pytest.mark.parametrize("boolean", VALID_BOOLEAN)
+def test_valid_boolean(boolean):
+    assert OpensshParser(_OpensshWriter().boolean(boolean).bytes()).boolean() == boolean
+
+
+@pytest.mark.parametrize("boolean", INVALID_BOOLEAN)
+def test_invalid_boolean(boolean):
+    with pytest.raises(TypeError):
+        _OpensshWriter().boolean(boolean)
+
+
+@pytest.mark.parametrize("uint32", VALID_UINT32)
+def test_valid_uint32(uint32):
+    assert OpensshParser(_OpensshWriter().uint32(uint32).bytes()).uint32() == uint32
+
+
+@pytest.mark.parametrize("uint32", INVALID_UINT32)
+def test_invalid_uint32(uint32):
+    with pytest.raises(ValueError):
+        _OpensshWriter().uint32(uint32)
+
+
+@pytest.mark.parametrize("uint64", VALID_UINT64)
+def test_valid_uint64(uint64):
+    assert OpensshParser(_OpensshWriter().uint64(uint64).bytes()).uint64() == uint64
+
+
+@pytest.mark.parametrize("uint64", INVALID_UINT64)
+def test_invalid_uint64(uint64):
+    with pytest.raises(ValueError):
+        _OpensshWriter().uint64(uint64)
+
+
+@pytest.mark.parametrize("ssh_string", VALID_STRING)
+def test_valid_string(ssh_string):
+    assert OpensshParser(_OpensshWriter().string(ssh_string).bytes()).string() == ssh_string
+
+
+@pytest.mark.parametrize("ssh_string", INVALID_STRING)
+def test_invalid_string(ssh_string):
+    with pytest.raises(TypeError):
+        _OpensshWriter().string(ssh_string)
+
+
+@pytest.mark.parametrize("mpint", VALID_MPINT)
+def test_valid_mpint(mpint):
+    assert OpensshParser(_OpensshWriter().mpint(mpint).bytes()).mpint() == mpint
+
+
+@pytest.mark.parametrize("mpint", INVALID_MPINT)
+def test_invalid_mpint(mpint):
+    with pytest.raises(TypeError):
+        _OpensshWriter().mpint(mpint)
+
+
+def test_valid_seek():
+    buffer = bytearray(b'buffer')
+    parser = OpensshParser(buffer)
+    parser.seek(len(buffer))
+    assert parser.remaining_bytes() == 0
+    parser.seek(-len(buffer))
+    assert parser.remaining_bytes() == len(buffer)
+
+
+def test_invalid_seek():
+    result = False
+    buffer = b'buffer'
+    parser = OpensshParser(buffer)
+
+    with pytest.raises(ValueError):
+        parser.seek(len(buffer) + 1)
+
+    with pytest.raises(ValueError):
+        parser.seek(-1)
+
+
+def test_writer_bytes():
+    buffer = bytearray(b'buffer')
+    assert _OpensshWriter(buffer).bytes() == buffer