Auth: Import milenage implementation from hostap (Jouni Malinen)

... and add integration into the osmo_auth core.

1 files changed, 329 insertions, 0 deletions

diff --git a/src/gsm/milenage/milenage.c b/src/gsm/milenage/milenage.c
new file mode 100644
index 00000000..cc4e95c5
--- /dev/null
+++ b/src/gsm/milenage/milenage.c
@@ -0,0 +1,329 @@
+/*
+ * 3GPP AKA - Milenage algorithm (3GPP TS 35.205, .206, .207, .208)
+ * Copyright (c) 2006-2007 <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ *
+ * This file implements an example authentication algorithm defined for 3GPP
+ * AKA. This can be used to implement a simple HLR/AuC into hlr_auc_gw to allow
+ * EAP-AKA to be tested properly with real USIM cards.
+ *
+ * This implementations assumes that the r1..r5 and c1..c5 constants defined in
+ * TS 35.206 are used, i.e., r1=64, r2=0, r3=32, r4=64, r5=96, c1=00..00,
+ * c2=00..01, c3=00..02, c4=00..04, c5=00..08. The block cipher is assumed to
+ * be AES (Rijndael).
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "aes_wrap.h"
+#include "milenage.h"
+
+
+/**
+ * milenage_f1 - Milenage f1 and f1* algorithms
+ * @opc: OPc = 128-bit value derived from OP and K
+ * @k: K = 128-bit subscriber key
+ * @_rand: RAND = 128-bit random challenge
+ * @sqn: SQN = 48-bit sequence number
+ * @amf: AMF = 16-bit authentication management field
+ * @mac_a: Buffer for MAC-A = 64-bit network authentication code, or %NULL
+ * @mac_s: Buffer for MAC-S = 64-bit resync authentication code, or %NULL
+ * Returns: 0 on success, -1 on failure
+ */
+int milenage_f1(const u8 *opc, const u8 *k, const u8 *_rand,
+		const u8 *sqn, const u8 *amf, u8 *mac_a, u8 *mac_s)
+{
+	u8 tmp1[16], tmp2[16], tmp3[16];
+	int i;
+
+	/* tmp1 = TEMP = E_K(RAND XOR OP_C) */
+	for (i = 0; i < 16; i++)
+		tmp1[i] = _rand[i] ^ opc[i];
+	if (aes_128_encrypt_block(k, tmp1, tmp1))
+		return -1;
+
+	/* tmp2 = IN1 = SQN || AMF || SQN || AMF */
+	os_memcpy(tmp2, sqn, 6);
+	os_memcpy(tmp2 + 6, amf, 2);
+	os_memcpy(tmp2 + 8, tmp2, 8);
+
+	/* OUT1 = E_K(TEMP XOR rot(IN1 XOR OP_C, r1) XOR c1) XOR OP_C */
+
+	/* rotate (tmp2 XOR OP_C) by r1 (= 0x40 = 8 bytes) */
+	for (i = 0; i < 16; i++)
+		tmp3[(i + 8) % 16] = tmp2[i] ^ opc[i];
+	/* XOR with TEMP = E_K(RAND XOR OP_C) */
+	for (i = 0; i < 16; i++)
+		tmp3[i] ^= tmp1[i];
+	/* XOR with c1 (= ..00, i.e., NOP) */
+
+	/* f1 || f1* = E_K(tmp3) XOR OP_c */
+	if (aes_128_encrypt_block(k, tmp3, tmp1))
+		return -1;
+	for (i = 0; i < 16; i++)
+		tmp1[i] ^= opc[i];
+	if (mac_a)
+		os_memcpy(mac_a, tmp1, 8); /* f1 */
+	if (mac_s)
+		os_memcpy(mac_s, tmp1 + 8, 8); /* f1* */
+	return 0;
+}
+
+
+/**
+ * milenage_f2345 - Milenage f2, f3, f4, f5, f5* algorithms
+ * @opc: OPc = 128-bit value derived from OP and K
+ * @k: K = 128-bit subscriber key
+ * @_rand: RAND = 128-bit random challenge
+ * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
+ * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
+ * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
+ * @ak: Buffer for AK = 48-bit anonymity key (f5), or %NULL
+ * @akstar: Buffer for AK = 48-bit anonymity key (f5*), or %NULL
+ * Returns: 0 on success, -1 on failure
+ */
+int milenage_f2345(const u8 *opc, const u8 *k, const u8 *_rand,
+		   u8 *res, u8 *ck, u8 *ik, u8 *ak, u8 *akstar)
+{
+	u8 tmp1[16], tmp2[16], tmp3[16];
+	int i;
+
+	/* tmp2 = TEMP = E_K(RAND XOR OP_C) */
+	for (i = 0; i < 16; i++)
+		tmp1[i] = _rand[i] ^ opc[i];
+	if (aes_128_encrypt_block(k, tmp1, tmp2))
+		return -1;
+
+	/* OUT2 = E_K(rot(TEMP XOR OP_C, r2) XOR c2) XOR OP_C */
+	/* OUT3 = E_K(rot(TEMP XOR OP_C, r3) XOR c3) XOR OP_C */
+	/* OUT4 = E_K(rot(TEMP XOR OP_C, r4) XOR c4) XOR OP_C */
+	/* OUT5 = E_K(rot(TEMP XOR OP_C, r5) XOR c5) XOR OP_C */
+
+	/* f2 and f5 */
+	/* rotate by r2 (= 0, i.e., NOP) */
+	for (i = 0; i < 16; i++)
+		tmp1[i] = tmp2[i] ^ opc[i];
+	tmp1[15] ^= 1; /* XOR c2 (= ..01) */
+	/* f5 || f2 = E_K(tmp1) XOR OP_c */
+	if (aes_128_encrypt_block(k, tmp1, tmp3))
+		return -1;
+	for (i = 0; i < 16; i++)
+		tmp3[i] ^= opc[i];
+	if (res)
+		os_memcpy(res, tmp3 + 8, 8); /* f2 */
+	if (ak)
+		os_memcpy(ak, tmp3, 6); /* f5 */
+
+	/* f3 */
+	if (ck) {
+		/* rotate by r3 = 0x20 = 4 bytes */
+		for (i = 0; i < 16; i++)
+			tmp1[(i + 12) % 16] = tmp2[i] ^ opc[i];
+		tmp1[15] ^= 2; /* XOR c3 (= ..02) */
+		if (aes_128_encrypt_block(k, tmp1, ck))
+			return -1;
+		for (i = 0; i < 16; i++)
+			ck[i] ^= opc[i];
+	}
+
+	/* f4 */
+	if (ik) {
+		/* rotate by r4 = 0x40 = 8 bytes */
+		for (i = 0; i < 16; i++)
+			tmp1[(i + 8) % 16] = tmp2[i] ^ opc[i];
+		tmp1[15] ^= 4; /* XOR c4 (= ..04) */
+		if (aes_128_encrypt_block(k, tmp1, ik))
+			return -1;
+		for (i = 0; i < 16; i++)
+			ik[i] ^= opc[i];
+	}
+
+	/* f5* */
+	if (akstar) {
+		/* rotate by r5 = 0x60 = 12 bytes */
+		for (i = 0; i < 16; i++)
+			tmp1[(i + 4) % 16] = tmp2[i] ^ opc[i];
+		tmp1[15] ^= 8; /* XOR c5 (= ..08) */
+		if (aes_128_encrypt_block(k, tmp1, tmp1))
+			return -1;
+		for (i = 0; i < 6; i++)
+			akstar[i] = tmp1[i] ^ opc[i];
+	}
+
+	return 0;
+}
+
+
+/**
+ * milenage_generate - Generate AKA AUTN,IK,CK,RES
+ * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
+ * @amf: AMF = 16-bit authentication management field
+ * @k: K = 128-bit subscriber key
+ * @sqn: SQN = 48-bit sequence number
+ * @_rand: RAND = 128-bit random challenge
+ * @autn: Buffer for AUTN = 128-bit authentication token
+ * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
+ * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
+ * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
+ * @res_len: Max length for res; set to used length or 0 on failure
+ */
+void milenage_generate(const u8 *opc, const u8 *amf, const u8 *k,
+		       const u8 *sqn, const u8 *_rand, u8 *autn, u8 *ik,
+		       u8 *ck, u8 *res, size_t *res_len)
+{
+	int i;
+	u8 mac_a[8], ak[6];
+
+	if (*res_len < 8) {
+		*res_len = 0;
+		return;
+	}
+	if (milenage_f1(opc, k, _rand, sqn, amf, mac_a, NULL) ||
+	    milenage_f2345(opc, k, _rand, res, ck, ik, ak, NULL)) {
+		*res_len = 0;
+		return;
+	}
+	*res_len = 8;
+
+	/* AUTN = (SQN ^ AK) || AMF || MAC */
+	for (i = 0; i < 6; i++)
+		autn[i] = sqn[i] ^ ak[i];
+	os_memcpy(autn + 6, amf, 2);
+	os_memcpy(autn + 8, mac_a, 8);
+}
+
+
+/**
+ * milenage_auts - Milenage AUTS validation
+ * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
+ * @k: K = 128-bit subscriber key
+ * @_rand: RAND = 128-bit random challenge
+ * @auts: AUTS = 112-bit authentication token from client
+ * @sqn: Buffer for SQN = 48-bit sequence number
+ * Returns: 0 = success (sqn filled), -1 on failure
+ */
+int milenage_auts(const u8 *opc, const u8 *k, const u8 *_rand, const u8 *auts,
+		  u8 *sqn)
+{
+	u8 amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */
+	u8 ak[6], mac_s[8];
+	int i;
+
+	if (milenage_f2345(opc, k, _rand, NULL, NULL, NULL, NULL, ak))
+		return -1;
+	for (i = 0; i < 6; i++)
+		sqn[i] = auts[i] ^ ak[i];
+	if (milenage_f1(opc, k, _rand, sqn, amf, NULL, mac_s) ||
+	    memcmp(mac_s, auts + 6, 8) != 0)
+		return -1;
+	return 0;
+}
+
+
+/**
+ * gsm_milenage - Generate GSM-Milenage (3GPP TS 55.205) authentication triplet
+ * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
+ * @k: K = 128-bit subscriber key
+ * @_rand: RAND = 128-bit random challenge
+ * @sres: Buffer for SRES = 32-bit SRES
+ * @kc: Buffer for Kc = 64-bit Kc
+ * Returns: 0 on success, -1 on failure
+ */
+int gsm_milenage(const u8 *opc, const u8 *k, const u8 *_rand, u8 *sres, u8 *kc)
+{
+	u8 res[8], ck[16], ik[16];
+	int i;
+
+	if (milenage_f2345(opc, k, _rand, res, ck, ik, NULL, NULL))
+		return -1;
+
+	for (i = 0; i < 8; i++)
+		kc[i] = ck[i] ^ ck[i + 8] ^ ik[i] ^ ik[i + 8];
+
+#ifdef GSM_MILENAGE_ALT_SRES
+	os_memcpy(sres, res, 4);
+#else /* GSM_MILENAGE_ALT_SRES */
+	for (i = 0; i < 4; i++)
+		sres[i] = res[i] ^ res[i + 4];
+#endif /* GSM_MILENAGE_ALT_SRES */
+	return 0;
+}
+
+
+/**
+ * milenage_generate - Generate AKA AUTN,IK,CK,RES
+ * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
+ * @k: K = 128-bit subscriber key
+ * @sqn: SQN = 48-bit sequence number
+ * @_rand: RAND = 128-bit random challenge
+ * @autn: AUTN = 128-bit authentication token
+ * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
+ * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
+ * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
+ * @res_len: Variable that will be set to RES length
+ * @auts: 112-bit buffer for AUTS
+ * Returns: 0 on success, -1 on failure, or -2 on synchronization failure
+ */
+int milenage_check(const u8 *opc, const u8 *k, const u8 *sqn, const u8 *_rand,
+		   const u8 *autn, u8 *ik, u8 *ck, u8 *res, size_t *res_len,
+		   u8 *auts)
+{
+	int i;
+	u8 mac_a[8], ak[6], rx_sqn[6];
+	const u8 *amf;
+
+	wpa_hexdump(MSG_DEBUG, "Milenage: AUTN", autn, 16);
+	wpa_hexdump(MSG_DEBUG, "Milenage: RAND", _rand, 16);
+
+	if (milenage_f2345(opc, k, _rand, res, ck, ik, ak, NULL))
+		return -1;
+
+	*res_len = 8;
+	wpa_hexdump_key(MSG_DEBUG, "Milenage: RES", res, *res_len);
+	wpa_hexdump_key(MSG_DEBUG, "Milenage: CK", ck, 16);
+	wpa_hexdump_key(MSG_DEBUG, "Milenage: IK", ik, 16);
+	wpa_hexdump_key(MSG_DEBUG, "Milenage: AK", ak, 6);
+
+	/* AUTN = (SQN ^ AK) || AMF || MAC */
+	for (i = 0; i < 6; i++)
+		rx_sqn[i] = autn[i] ^ ak[i];
+	wpa_hexdump(MSG_DEBUG, "Milenage: SQN", rx_sqn, 6);
+
+	if (os_memcmp(rx_sqn, sqn, 6) <= 0) {
+		u8 auts_amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */
+		if (milenage_f2345(opc, k, _rand, NULL, NULL, NULL, NULL, ak))
+			return -1;
+		wpa_hexdump_key(MSG_DEBUG, "Milenage: AK*", ak, 6);
+		for (i = 0; i < 6; i++)
+			auts[i] = sqn[i] ^ ak[i];
+		if (milenage_f1(opc, k, _rand, sqn, auts_amf, NULL, auts + 6))
+			return -1;
+		wpa_hexdump(MSG_DEBUG, "Milenage: AUTS", auts, 14);
+		return -2;
+	}
+
+	amf = autn + 6;
+	wpa_hexdump(MSG_DEBUG, "Milenage: AMF", amf, 2);
+	if (milenage_f1(opc, k, _rand, rx_sqn, amf, mac_a, NULL))
+		return -1;
+
+	wpa_hexdump(MSG_DEBUG, "Milenage: MAC_A", mac_a, 8);
+
+	if (os_memcmp(mac_a, autn + 8, 8) != 0) {
+		wpa_printf(MSG_DEBUG, "Milenage: MAC mismatch");
+		wpa_hexdump(MSG_DEBUG, "Milenage: Received MAC_A",
+			    autn + 8, 8);
+		return -1;
+	}
+
+	return 0;
+}