Make early protocol auth mechanism generic, and add SRP

Adds everything needed for SRP (and everything works too),
but still deactivated, as protocol v25 init packets aren't final yet.
Can be activated by changing the LATEST_PROTOCOL_VERSION header to 25
inside networkprotocol.h.

1 files changed, 171 insertions, 0 deletions

diff --git a/src/util/srp.h b/src/util/srp.h
new file mode 100644
index 000000000..15a2b8a68
--- /dev/null
+++ b/src/util/srp.h
@@ -0,0 +1,171 @@
+/*
+ * Secure Remote Password 6a implementation
+ * https://github.com/est31/csrp-gmp
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2010, 2013 Tom Cocagne, 2015 est31 <MTest31@outlook.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is furnished to do
+ * so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+/*
+ *
+ * Purpose:       This is a direct implementation of the Secure Remote Password
+ *                Protocol version 6a as described by
+ *                http://srp.stanford.edu/design.html
+ *
+ * Author:        tom.cocagne@gmail.com (Tom Cocagne)
+ *
+ * Dependencies:  LibGMP
+ *
+ * Usage:         Refer to test_srp.c for a demonstration
+ *
+ * Notes:
+ *    This library allows multiple combinations of hashing algorithms and
+ *    prime number constants. For authentication to succeed, the hash and
+ *    prime number constants must match between
+ *    srp_create_salted_verification_key(), srp_user_new(),
+ *    and srp_verifier_new(). A recommended approach is to determine the
+ *    desired level of security for an application and globally define the
+ *    hash and prime number constants to the predetermined values.
+ *
+ *    As one might suspect, more bits means more security. As one might also
+ *    suspect, more bits also means more processing time. The test_srp.c
+ *    program can be easily modified to profile various combinations of
+ *    hash & prime number pairings.
+ */
+
+#ifndef SRP_H
+#define SRP_H
+
+
+struct SRPVerifier;
+struct SRPUser;
+
+typedef enum
+{
+	SRP_NG_1024,
+	SRP_NG_2048,
+	SRP_NG_4096,
+	SRP_NG_8192,
+	SRP_NG_CUSTOM
+} SRP_NGType;
+
+typedef enum
+{
+	/*SRP_SHA1,*/
+	/*SRP_SHA224,*/
+	SRP_SHA256,
+	/*SRP_SHA384,
+	SRP_SHA512*/
+} SRP_HashAlgorithm;
+
+/* Out: bytes_v, len_v
+ *
+ * The caller is responsible for freeing the memory allocated for bytes_v
+ *
+ * The n_hex and g_hex parameters should be 0 unless SRP_NG_CUSTOM is used for ng_type.
+ * If provided, they must contain ASCII text of the hexidecimal notation.
+ *
+ * If bytes_s == NULL, it is filled with random data. The caller is responsible for freeing.
+ */
+void srp_create_salted_verification_key( SRP_HashAlgorithm alg,
+	SRP_NGType ng_type, const char *username_for_verifier,
+	const unsigned char *password, size_t len_password,
+	unsigned char **bytes_s,  size_t *len_s,
+	unsigned char **bytes_v, size_t *len_v,
+	const char * n_hex, const char *g_hex );
+
+/* Out: bytes_B, len_B.
+ *
+ * On failure, bytes_B will be set to NULL and len_B will be set to 0
+ *
+ * The n_hex and g_hex parameters should be 0 unless SRP_NG_CUSTOM is used for ng_type
+ *
+ * If bytes_b == NULL, random data is used for b.
+ */
+struct SRPVerifier* srp_verifier_new(SRP_HashAlgorithm alg, SRP_NGType ng_type,
+	const char *username,
+	const unsigned char *bytes_s, size_t len_s,
+	const unsigned char *bytes_v, size_t len_v,
+	const unsigned char *bytes_A, size_t len_A,
+	const unsigned char *bytes_b, size_t len_b,
+	unsigned char** bytes_B, size_t *len_B,
+	const char* n_hex, const char* g_hex);
+
+
+void srp_verifier_delete( struct SRPVerifier* ver );
+
+
+int srp_verifier_is_authenticated( struct SRPVerifier* ver );
+
+
+const char * srp_verifier_get_username( struct SRPVerifier* ver );
+
+/* key_length may be null */
+const unsigned char* srp_verifier_get_session_key( struct SRPVerifier* ver,
+	size_t *key_length );
+
+
+size_t srp_verifier_get_session_key_length(struct SRPVerifier* ver);
+
+
+/* user_M must be exactly srp_verifier_get_session_key_length() bytes in size */
+void srp_verifier_verify_session( struct SRPVerifier* ver,
+	const unsigned char* user_M, unsigned char** bytes_HAMK );
+
+/*******************************************************************************/
+
+/* The n_hex and g_hex parameters should be 0 unless SRP_NG_CUSTOM is used for ng_type */
+struct SRPUser *srp_user_new(SRP_HashAlgorithm alg, SRP_NGType ng_type,
+	const char *username, const char *username_for_verifier,
+	const unsigned char *bytes_password, size_t len_password,
+	const char *n_hex, const char *g_hex);
+
+void srp_user_delete(struct SRPUser * usr);
+
+int srp_user_is_authenticated(struct SRPUser * usr);
+
+
+const char* srp_user_get_username(struct SRPUser * usr);
+
+/* key_length may be null */
+const unsigned char* srp_user_get_session_key(struct SRPUser* usr, size_t* key_length);
+
+size_t srp_user_get_session_key_length(struct SRPUser* usr);
+
+/* Output: username, bytes_A, len_A. If you don't want it get written, set username to NULL.
+ * If bytes_a == NULL, random data is used for a. */
+void srp_user_start_authentication(struct SRPUser* usr, char** username,
+	const unsigned char* bytes_a, size_t len_a,
+	unsigned char** bytes_A, size_t* len_A);
+
+/* Output: bytes_M, len_M  (len_M may be null and will always be
+ *                          srp_user_get_session_key_length() bytes in size) */
+void srp_user_process_challenge(struct SRPUser *usr,
+	const unsigned char *bytes_s, size_t len_s,
+	const unsigned char *bytes_B, size_t len_B,
+	unsigned char **bytes_M, size_t *len_M);
+
+/* bytes_HAMK must be exactly srp_user_get_session_key_length() bytes in size */
+void srp_user_verify_session(struct SRPUser* usr, const unsigned char* bytes_HAMK);
+
+#endif /* Include Guard */