Add salt parameter to hash generation for sha256 plugins (#631)

* add salt parameter to hash generation for sha256 plugin
* technomax review modification
* no general user test for salt

plugins/module_utils/implementations/mysql/hash.py

@@ -0,0 +1,125 @@
+"""
+Generate MySQL sha256 compatible plugins hash for a given password and salt
+
+based on
+ * https://www.akkadia.org/drepper/SHA-crypt.txt
+ * https://crypto.stackexchange.com/questions/77427/whats-the-algorithm-behind-mysqls-sha256-password-hashing-scheme/111174#111174
+ * https://github.com/hashcat/hashcat/blob/master/tools/test_modules/m07400.pm
+"""
+
+from __future__ import absolute_import, division, print_function
+
+__metaclass__ = type
+
+import hashlib
+
+
+def _to64(v, n):
+    """Convert a 32-bit integer to a base-64 string"""
+    i64 = (
+        [".", "/"]
+        + [chr(x) for x in range(48, 58)]
+        + [chr(x) for x in range(65, 91)]
+        + [chr(x) for x in range(97, 123)]
+    )
+    result = ""
+    while n > 0:
+        n -= 1
+        result += i64[v & 0x3F]
+        v >>= 6
+    return result
+
+
+def _hashlib_sha256(data):
+    """Return SHA-256 digest from hashlib ."""
+    return hashlib.sha256(data).digest()
+
+
+def _sha256_digest(key, salt, loops):
+    """Return a SHA-256 digest of the concatenation of the key, the salt, and the key, repeated as necessary."""
+    # https://www.akkadia.org/drepper/SHA-crypt.txt
+    num_bytes = 32
+    bytes_key = key.encode()
+    bytes_salt = salt.encode()
+    digest_b = _hashlib_sha256(bytes_key + bytes_salt + bytes_key)
+
+    tmp = bytes_key + bytes_salt
+    for i in range(len(bytes_key), 0, -num_bytes):
+        tmp += digest_b if i > num_bytes else digest_b[:i]
+
+    i = len(bytes_key)
+    while i > 0:
+        tmp += digest_b if (i & 1) != 0 else bytes_key
+        i >>= 1
+
+    digest_a = _hashlib_sha256(tmp)
+
+    tmp = b""
+    for i in range(len(bytes_key)):
+        tmp += bytes_key
+
+    digest_dp = _hashlib_sha256(tmp)
+
+    byte_sequence_p = b""
+    for i in range(len(bytes_key), 0, -num_bytes):
+        byte_sequence_p += digest_dp if i > num_bytes else digest_dp[:i]
+
+    tmp = b""
+    til = 16 + digest_a[0]
+
+    for i in range(til):
+        tmp += bytes_salt
+
+    digest_ds = _hashlib_sha256(tmp)
+
+    byte_sequence_s = b""
+    for i in range(len(bytes_salt), 0, -num_bytes):
+        byte_sequence_s += digest_ds if i > num_bytes else digest_ds[:i]
+
+    digest_c = digest_a
+
+    for i in range(loops):
+        tmp = byte_sequence_p if (i & 1) else digest_c
+        if i % 3:
+            tmp += byte_sequence_s
+        if i % 7:
+            tmp += byte_sequence_p
+        tmp += digest_c if (i & 1) else byte_sequence_p
+        digest_c = _hashlib_sha256(tmp)
+
+    inc1, inc2, mod, end = (10, 21, 30, 0)
+
+    i = 0
+    tmp = ""
+
+    while True:
+        tmp += _to64(
+            (digest_c[i] << 16)
+            | (digest_c[(i + inc1) % mod] << 8)
+            | digest_c[(i + inc1 * 2) % mod],
+            4,
+        )
+        i = (i + inc2) % mod
+        if i == end:
+            break
+
+    tmp += _to64((digest_c[31] << 8) | digest_c[30], 3)
+
+    return tmp
+
+
+def mysql_sha256_password_hash(password, salt):
+    """Return a MySQL compatible caching_sha2_password hash in raw format."""
+    if len(salt) != 20:
+        raise ValueError("Salt must be 20 characters long.")
+
+    count = 5
+    iteration = 1000 * count
+
+    digest = _sha256_digest(password, salt, iteration)
+    return "$A${0:>03}${1}{2}".format(count, salt, digest)
+
+
+def mysql_sha256_password_hash_hex(password, salt):
+    """Return a MySQL compatible caching_sha2_password hash in hex format."""
+    return mysql_sha256_password_hash(password, salt).encode().hex().upper()