1  /*
2   * EAP server/peer: EAP-GPSK shared routines
3   * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
4   *
5   * This software may be distributed under the terms of the BSD license.
6   * See README for more details.
7   */
8  
9  #include "includes.h"
10  
11  #include "common.h"
12  #include "crypto/aes_wrap.h"
13  #include "crypto/sha256.h"
14  #include "eap_defs.h"
15  #include "eap_gpsk_common.h"
16  
17  
18  /**
19   * eap_gpsk_supported_ciphersuite - Check whether ciphersuite is supported
20   * @vendor: CSuite/Vendor
21   * @specifier: CSuite/Specifier
22   * Returns: 1 if ciphersuite is support, or 0 if not
23   */
eap_gpsk_supported_ciphersuite(int vendor,int specifier)24  int eap_gpsk_supported_ciphersuite(int vendor, int specifier)
25  {
26  	if (vendor == EAP_GPSK_VENDOR_IETF &&
27  	    specifier == EAP_GPSK_CIPHER_AES)
28  		return 1;
29  #ifdef EAP_GPSK_SHA256
30  	if (vendor == EAP_GPSK_VENDOR_IETF &&
31  	    specifier == EAP_GPSK_CIPHER_SHA256)
32  		return 1;
33  #endif /* EAP_GPSK_SHA256 */
34  	return 0;
35  }
36  
37  
eap_gpsk_gkdf_cmac(const u8 * psk,const u8 * data,size_t data_len,u8 * buf,size_t len)38  static int eap_gpsk_gkdf_cmac(const u8 *psk /* Y */,
39  			      const u8 *data /* Z */, size_t data_len,
40  			      u8 *buf, size_t len /* X */)
41  {
42  	u8 *opos;
43  	size_t i, n, hashlen, left, clen;
44  	u8 ibuf[2], hash[16];
45  	const u8 *addr[2];
46  	size_t vlen[2];
47  
48  	hashlen = sizeof(hash);
49  	/* M_i = MAC_Y (i || Z); (MAC = AES-CMAC-128) */
50  	addr[0] = ibuf;
51  	vlen[0] = sizeof(ibuf);
52  	addr[1] = data;
53  	vlen[1] = data_len;
54  
55  	opos = buf;
56  	left = len;
57  	n = (len + hashlen - 1) / hashlen;
58  	for (i = 1; i <= n; i++) {
59  		WPA_PUT_BE16(ibuf, i);
60  		if (omac1_aes_128_vector(psk, 2, addr, vlen, hash))
61  			return -1;
62  		clen = left > hashlen ? hashlen : left;
63  		os_memcpy(opos, hash, clen);
64  		opos += clen;
65  		left -= clen;
66  	}
67  
68  	return 0;
69  }
70  
71  
72  #ifdef EAP_GPSK_SHA256
eap_gpsk_gkdf_sha256(const u8 * psk,const u8 * data,size_t data_len,u8 * buf,size_t len)73  static int eap_gpsk_gkdf_sha256(const u8 *psk /* Y */,
74  				const u8 *data /* Z */, size_t data_len,
75  				u8 *buf, size_t len /* X */)
76  {
77  	u8 *opos;
78  	size_t i, n, hashlen, left, clen;
79  	u8 ibuf[2], hash[SHA256_MAC_LEN];
80  	const u8 *addr[2];
81  	size_t vlen[2];
82  
83  	hashlen = SHA256_MAC_LEN;
84  	/* M_i = MAC_Y (i || Z); (MAC = HMAC-SHA256) */
85  	addr[0] = ibuf;
86  	vlen[0] = sizeof(ibuf);
87  	addr[1] = data;
88  	vlen[1] = data_len;
89  
90  	opos = buf;
91  	left = len;
92  	n = (len + hashlen - 1) / hashlen;
93  	for (i = 1; i <= n; i++) {
94  		WPA_PUT_BE16(ibuf, i);
95  		if (hmac_sha256_vector(psk, 32, 2, addr, vlen, hash))
96  			return -1;
97  		clen = left > hashlen ? hashlen : left;
98  		os_memcpy(opos, hash, clen);
99  		opos += clen;
100  		left -= clen;
101  	}
102  
103  	return 0;
104  }
105  #endif /* EAP_GPSK_SHA256 */
106  
107  
eap_gpsk_derive_keys_helper(u32 csuite_specifier,u8 * kdf_out,size_t kdf_out_len,const u8 * psk,size_t psk_len,const u8 * seed,size_t seed_len,u8 * msk,u8 * emsk,u8 * sk,size_t sk_len,u8 * pk,size_t pk_len)108  static int eap_gpsk_derive_keys_helper(u32 csuite_specifier,
109  				       u8 *kdf_out, size_t kdf_out_len,
110  				       const u8 *psk, size_t psk_len,
111  				       const u8 *seed, size_t seed_len,
112  				       u8 *msk, u8 *emsk,
113  				       u8 *sk, size_t sk_len,
114  				       u8 *pk, size_t pk_len)
115  {
116  	u8 mk[32], *pos, *data;
117  	size_t data_len, mk_len;
118  	int (*gkdf)(const u8 *_psk, const u8 *_data, size_t _data_len,
119  		    u8 *buf, size_t len);
120  
121  	gkdf = NULL;
122  	switch (csuite_specifier) {
123  	case EAP_GPSK_CIPHER_AES:
124  		gkdf = eap_gpsk_gkdf_cmac;
125  		mk_len = 16;
126  		break;
127  #ifdef EAP_GPSK_SHA256
128  	case EAP_GPSK_CIPHER_SHA256:
129  		gkdf = eap_gpsk_gkdf_sha256;
130  		mk_len = SHA256_MAC_LEN;
131  		break;
132  #endif /* EAP_GPSK_SHA256 */
133  	default:
134  		return -1;
135  	}
136  
137  	if (psk_len < mk_len)
138  		return -1;
139  
140  	data_len = 2 + psk_len + 6 + seed_len;
141  	data = os_malloc(data_len);
142  	if (data == NULL)
143  		return -1;
144  	pos = data;
145  	WPA_PUT_BE16(pos, psk_len);
146  	pos += 2;
147  	os_memcpy(pos, psk, psk_len);
148  	pos += psk_len;
149  	WPA_PUT_BE32(pos, EAP_GPSK_VENDOR_IETF); /* CSuite/Vendor = IETF */
150  	pos += 4;
151  	WPA_PUT_BE16(pos, csuite_specifier); /* CSuite/Specifier */
152  	pos += 2;
153  	os_memcpy(pos, seed, seed_len); /* inputString */
154  	wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: Data to MK derivation",
155  			data, data_len);
156  
157  	if (gkdf(psk, data, data_len, mk, mk_len) < 0) {
158  		os_free(data);
159  		return -1;
160  	}
161  	os_free(data);
162  	wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: MK", mk, mk_len);
163  
164  	if (gkdf(mk, seed, seed_len, kdf_out, kdf_out_len) < 0)
165  		return -1;
166  
167  	pos = kdf_out;
168  	wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: MSK", pos, EAP_MSK_LEN);
169  	os_memcpy(msk, pos, EAP_MSK_LEN);
170  	pos += EAP_MSK_LEN;
171  
172  	wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: EMSK", pos, EAP_EMSK_LEN);
173  	os_memcpy(emsk, pos, EAP_EMSK_LEN);
174  	pos += EAP_EMSK_LEN;
175  
176  	wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: SK", pos, sk_len);
177  	os_memcpy(sk, pos, sk_len);
178  	pos += sk_len;
179  
180  	if (pk) {
181  		wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PK", pos, pk_len);
182  		os_memcpy(pk, pos, pk_len);
183  	}
184  
185  	return 0;
186  }
187  
188  
eap_gpsk_derive_keys_aes(const u8 * psk,size_t psk_len,const u8 * seed,size_t seed_len,u8 * msk,u8 * emsk,u8 * sk,size_t * sk_len,u8 * pk,size_t * pk_len)189  static int eap_gpsk_derive_keys_aes(const u8 *psk, size_t psk_len,
190  				    const u8 *seed, size_t seed_len,
191  				    u8 *msk, u8 *emsk, u8 *sk, size_t *sk_len,
192  				    u8 *pk, size_t *pk_len)
193  {
194  #define EAP_GPSK_SK_LEN_AES 16
195  #define EAP_GPSK_PK_LEN_AES 16
196  	u8 kdf_out[EAP_MSK_LEN + EAP_EMSK_LEN + EAP_GPSK_SK_LEN_AES +
197  		   EAP_GPSK_PK_LEN_AES];
198  
199  	/*
200  	 * inputString = RAND_Peer || ID_Peer || RAND_Server || ID_Server
201  	 *            (= seed)
202  	 * KS = 16, PL = psk_len, CSuite_Sel = 0x00000000 0x0001
203  	 * MK = GKDF-16 (PSK[0..15], PL || PSK || CSuite_Sel || inputString)
204  	 * MSK = GKDF-160 (MK, inputString)[0..63]
205  	 * EMSK = GKDF-160 (MK, inputString)[64..127]
206  	 * SK = GKDF-160 (MK, inputString)[128..143]
207  	 * PK = GKDF-160 (MK, inputString)[144..159]
208  	 * zero = 0x00 || 0x00 || ... || 0x00 (16 times)
209  	 * Method-ID = GKDF-16 (zero, "Method ID" || EAP_Method_Type ||
210  	 *                      CSuite_Sel || inputString)
211  	 */
212  
213  	*sk_len = EAP_GPSK_SK_LEN_AES;
214  	*pk_len = EAP_GPSK_PK_LEN_AES;
215  
216  	return eap_gpsk_derive_keys_helper(EAP_GPSK_CIPHER_AES,
217  					   kdf_out, sizeof(kdf_out),
218  					   psk, psk_len, seed, seed_len,
219  					   msk, emsk, sk, *sk_len,
220  					   pk, *pk_len);
221  }
222  
223  
224  #ifdef EAP_GPSK_SHA256
eap_gpsk_derive_keys_sha256(const u8 * psk,size_t psk_len,const u8 * seed,size_t seed_len,u8 * msk,u8 * emsk,u8 * sk,size_t * sk_len)225  static int eap_gpsk_derive_keys_sha256(const u8 *psk, size_t psk_len,
226  				       const u8 *seed, size_t seed_len,
227  				       u8 *msk, u8 *emsk,
228  				       u8 *sk, size_t *sk_len)
229  {
230  #define EAP_GPSK_SK_LEN_SHA256 SHA256_MAC_LEN
231  #define EAP_GPSK_PK_LEN_SHA256 SHA256_MAC_LEN
232  	u8 kdf_out[EAP_MSK_LEN + EAP_EMSK_LEN + EAP_GPSK_SK_LEN_SHA256 +
233  		   EAP_GPSK_PK_LEN_SHA256];
234  
235  	/*
236  	 * inputString = RAND_Peer || ID_Peer || RAND_Server || ID_Server
237  	 *            (= seed)
238  	 * KS = 32, PL = psk_len, CSuite_Sel = 0x00000000 0x0002
239  	 * MK = GKDF-32 (PSK[0..31], PL || PSK || CSuite_Sel || inputString)
240  	 * MSK = GKDF-160 (MK, inputString)[0..63]
241  	 * EMSK = GKDF-160 (MK, inputString)[64..127]
242  	 * SK = GKDF-160 (MK, inputString)[128..159]
243  	 * zero = 0x00 || 0x00 || ... || 0x00 (32 times)
244  	 * Method-ID = GKDF-16 (zero, "Method ID" || EAP_Method_Type ||
245  	 *                      CSuite_Sel || inputString)
246  	 */
247  
248  	*sk_len = EAP_GPSK_SK_LEN_SHA256;
249  
250  	return eap_gpsk_derive_keys_helper(EAP_GPSK_CIPHER_SHA256,
251  					   kdf_out, sizeof(kdf_out),
252  					   psk, psk_len, seed, seed_len,
253  					   msk, emsk, sk, *sk_len,
254  					   NULL, 0);
255  }
256  #endif /* EAP_GPSK_SHA256 */
257  
258  
259  /**
260   * eap_gpsk_derive_keys - Derive EAP-GPSK keys
261   * @psk: Pre-shared key
262   * @psk_len: Length of psk in bytes
263   * @vendor: CSuite/Vendor
264   * @specifier: CSuite/Specifier
265   * @rand_peer: 32-byte RAND_Peer
266   * @rand_server: 32-byte RAND_Server
267   * @id_peer: ID_Peer
268   * @id_peer_len: Length of ID_Peer
269   * @id_server: ID_Server
270   * @id_server_len: Length of ID_Server
271   * @msk: Buffer for 64-byte MSK
272   * @emsk: Buffer for 64-byte EMSK
273   * @sk: Buffer for SK (at least EAP_GPSK_MAX_SK_LEN bytes)
274   * @sk_len: Buffer for returning length of SK
275   * @pk: Buffer for PK (at least EAP_GPSK_MAX_PK_LEN bytes)
276   * @pk_len: Buffer for returning length of PK
277   * Returns: 0 on success, -1 on failure
278   */
eap_gpsk_derive_keys(const u8 * psk,size_t psk_len,int vendor,int specifier,const u8 * rand_peer,const u8 * rand_server,const u8 * id_peer,size_t id_peer_len,const u8 * id_server,size_t id_server_len,u8 * msk,u8 * emsk,u8 * sk,size_t * sk_len,u8 * pk,size_t * pk_len)279  int eap_gpsk_derive_keys(const u8 *psk, size_t psk_len, int vendor,
280  			 int specifier,
281  			 const u8 *rand_peer, const u8 *rand_server,
282  			 const u8 *id_peer, size_t id_peer_len,
283  			 const u8 *id_server, size_t id_server_len,
284  			 u8 *msk, u8 *emsk, u8 *sk, size_t *sk_len,
285  			 u8 *pk, size_t *pk_len)
286  {
287  	u8 *seed, *pos;
288  	int ret;
289  
290  	wpa_printf(MSG_DEBUG, "EAP-GPSK: Deriving keys (%d:%d)",
291  		   vendor, specifier);
292  
293  	if (vendor != EAP_GPSK_VENDOR_IETF)
294  		return -1;
295  
296  	wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PSK", psk, psk_len);
297  
298  	/* Seed = RAND_Peer || ID_Peer || RAND_Server || ID_Server */
299  	seed = os_malloc(2 * EAP_GPSK_RAND_LEN + id_server_len + id_peer_len);
300  	if (seed == NULL) {
301  		wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to allocate memory "
302  			   "for key derivation");
303  		return -1;
304  	}
305  
306  	pos = seed;
307  	os_memcpy(pos, rand_peer, EAP_GPSK_RAND_LEN);
308  	pos += EAP_GPSK_RAND_LEN;
309  	os_memcpy(pos, id_peer, id_peer_len);
310  	pos += id_peer_len;
311  	os_memcpy(pos, rand_server, EAP_GPSK_RAND_LEN);
312  	pos += EAP_GPSK_RAND_LEN;
313  	os_memcpy(pos, id_server, id_server_len);
314  	pos += id_server_len;
315  	wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Seed", seed, pos - seed);
316  
317  	switch (specifier) {
318  	case EAP_GPSK_CIPHER_AES:
319  		ret = eap_gpsk_derive_keys_aes(psk, psk_len, seed, pos - seed,
320  					       msk, emsk, sk, sk_len,
321  					       pk, pk_len);
322  		break;
323  #ifdef EAP_GPSK_SHA256
324  	case EAP_GPSK_CIPHER_SHA256:
325  		ret = eap_gpsk_derive_keys_sha256(psk, psk_len, seed,
326  						  pos - seed,
327  						  msk, emsk, sk, sk_len);
328  		break;
329  #endif /* EAP_GPSK_SHA256 */
330  	default:
331  		wpa_printf(MSG_DEBUG, "EAP-GPSK: Unknown cipher %d:%d used in "
332  			   "key derivation", vendor, specifier);
333  		ret = -1;
334  		break;
335  	}
336  
337  	os_free(seed);
338  
339  	return ret;
340  }
341  
342  
eap_gpsk_derive_mid_helper(u32 csuite_specifier,u8 * kdf_out,size_t kdf_out_len,const u8 * psk,const u8 * seed,size_t seed_len,u8 method_type)343  static int eap_gpsk_derive_mid_helper(u32 csuite_specifier,
344  				      u8 *kdf_out, size_t kdf_out_len,
345  				      const u8 *psk, const u8 *seed,
346  				      size_t seed_len, u8 method_type)
347  {
348  	u8 *pos, *data;
349  	size_t data_len;
350  	int (*gkdf)(const u8 *_psk, const u8 *_data, size_t _data_len,
351  		    u8 *buf, size_t len);
352  
353  	gkdf = NULL;
354  	switch (csuite_specifier) {
355  	case EAP_GPSK_CIPHER_AES:
356  		gkdf = eap_gpsk_gkdf_cmac;
357  		break;
358  #ifdef EAP_GPSK_SHA256
359  	case EAP_GPSK_CIPHER_SHA256:
360  		gkdf = eap_gpsk_gkdf_sha256;
361  		break;
362  #endif /* EAP_GPSK_SHA256 */
363  	default:
364  		wpa_printf(MSG_DEBUG, "EAP-GPSK: Unknown cipher %d used in "
365  			   "Session-Id derivation", csuite_specifier);
366  		return -1;
367  	}
368  
369  #define SID_LABEL "Method ID"
370  	/* "Method ID" || EAP_Method_Type || CSuite_Sel || inputString */
371  	data_len = strlen(SID_LABEL) + 1 + 6 + seed_len;
372  	data = os_malloc(data_len);
373  	if (data == NULL)
374  		return -1;
375  	pos = data;
376  	os_memcpy(pos, SID_LABEL, strlen(SID_LABEL));
377  	pos += strlen(SID_LABEL);
378  #undef SID_LABEL
379  	os_memcpy(pos, &method_type, 1);
380  	pos += 1;
381  	WPA_PUT_BE32(pos, EAP_GPSK_VENDOR_IETF); /* CSuite/Vendor = IETF */
382  	pos += 4;
383  	WPA_PUT_BE16(pos, csuite_specifier); /* CSuite/Specifier */
384  	pos += 2;
385  	os_memcpy(pos, seed, seed_len); /* inputString */
386  	wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Data to Method ID derivation",
387  		    data, data_len);
388  
389  	if (gkdf(psk, data, data_len, kdf_out, kdf_out_len) < 0) {
390  		os_free(data);
391  		return -1;
392  	}
393  	os_free(data);
394  	wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Method ID", kdf_out, kdf_out_len);
395  
396  	return 0;
397  }
398  
399  
400  /**
401   * eap_gpsk_session_id - Derive EAP-GPSK Session ID
402   * @psk: Pre-shared key
403   * @psk_len: Length of psk in bytes
404   * @vendor: CSuite/Vendor
405   * @specifier: CSuite/Specifier
406   * @rand_peer: 32-byte RAND_Peer
407   * @rand_server: 32-byte RAND_Server
408   * @id_peer: ID_Peer
409   * @id_peer_len: Length of ID_Peer
410   * @id_server: ID_Server
411   * @id_server_len: Length of ID_Server
412   * @method_type: EAP Authentication Method Type
413   * @sid: Buffer for 17-byte Session ID
414   * @sid_len: Buffer for returning length of Session ID
415   * Returns: 0 on success, -1 on failure
416   */
eap_gpsk_derive_session_id(const u8 * psk,size_t psk_len,int vendor,int specifier,const u8 * rand_peer,const u8 * rand_server,const u8 * id_peer,size_t id_peer_len,const u8 * id_server,size_t id_server_len,u8 method_type,u8 * sid,size_t * sid_len)417  int eap_gpsk_derive_session_id(const u8 *psk, size_t psk_len, int vendor,
418  			       int specifier,
419  			       const u8 *rand_peer, const u8 *rand_server,
420  			       const u8 *id_peer, size_t id_peer_len,
421  			       const u8 *id_server, size_t id_server_len,
422  			       u8 method_type, u8 *sid, size_t *sid_len)
423  {
424  	u8 *seed, *pos;
425  	u8 kdf_out[16];
426  	int ret;
427  
428  	wpa_printf(MSG_DEBUG, "EAP-GPSK: Deriving Session ID(%d:%d)",
429  		   vendor, specifier);
430  
431  	if (vendor != EAP_GPSK_VENDOR_IETF)
432  		return -1;
433  
434  	wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PSK", psk, psk_len);
435  
436  	/*
437  	 * inputString = RAND_Peer || ID_Peer || RAND_Server || ID_Server
438  	 *            (= seed)
439  	 * KS = 16, CSuite_Sel = 0x00000000 0x0001
440  	 * Method-ID = GKDF-16 (zero, "Method ID" || EAP_Method_Type ||
441  	 *                      CSuite_Sel || inputString)
442  	 */
443  	seed = os_malloc(2 * EAP_GPSK_RAND_LEN + id_server_len + id_peer_len);
444  	if (seed == NULL) {
445  		wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to allocate memory "
446  			   "for Session-Id derivation");
447  		return -1;
448  	}
449  
450  	pos = seed;
451  	os_memcpy(pos, rand_peer, EAP_GPSK_RAND_LEN);
452  	pos += EAP_GPSK_RAND_LEN;
453  	os_memcpy(pos, id_peer, id_peer_len);
454  	pos += id_peer_len;
455  	os_memcpy(pos, rand_server, EAP_GPSK_RAND_LEN);
456  	pos += EAP_GPSK_RAND_LEN;
457  	os_memcpy(pos, id_server, id_server_len);
458  	pos += id_server_len;
459  	wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Seed", seed, pos - seed);
460  
461  	ret = eap_gpsk_derive_mid_helper(specifier,
462  					 kdf_out, sizeof(kdf_out),
463  					 psk, seed, pos - seed,
464  					 method_type);
465  
466  	sid[0] = method_type;
467  	os_memcpy(sid + 1, kdf_out, sizeof(kdf_out));
468  	*sid_len = 1 + sizeof(kdf_out);
469  
470  	os_free(seed);
471  
472  	return ret;
473  }
474  
475  
476  /**
477   * eap_gpsk_mic_len - Get the length of the MIC
478   * @vendor: CSuite/Vendor
479   * @specifier: CSuite/Specifier
480   * Returns: MIC length in bytes
481   */
eap_gpsk_mic_len(int vendor,int specifier)482  size_t eap_gpsk_mic_len(int vendor, int specifier)
483  {
484  	if (vendor != EAP_GPSK_VENDOR_IETF)
485  		return 0;
486  
487  	switch (specifier) {
488  	case EAP_GPSK_CIPHER_AES:
489  		return 16;
490  #ifdef EAP_GPSK_SHA256
491  	case EAP_GPSK_CIPHER_SHA256:
492  		return 32;
493  #endif /* EAP_GPSK_SHA256 */
494  	default:
495  		return 0;
496  	}
497  }
498  
499  
eap_gpsk_compute_mic_aes(const u8 * sk,size_t sk_len,const u8 * data,size_t len,u8 * mic)500  static int eap_gpsk_compute_mic_aes(const u8 *sk, size_t sk_len,
501  				    const u8 *data, size_t len, u8 *mic)
502  {
503  	if (sk_len != 16) {
504  		wpa_printf(MSG_DEBUG, "EAP-GPSK: Invalid SK length %lu for "
505  			   "AES-CMAC MIC", (unsigned long) sk_len);
506  		return -1;
507  	}
508  
509  	return omac1_aes_128(sk, data, len, mic);
510  }
511  
512  
513  /**
514   * eap_gpsk_compute_mic - Compute EAP-GPSK MIC for an EAP packet
515   * @sk: Session key SK from eap_gpsk_derive_keys()
516   * @sk_len: SK length in bytes from eap_gpsk_derive_keys()
517   * @vendor: CSuite/Vendor
518   * @specifier: CSuite/Specifier
519   * @data: Input data to MIC
520   * @len: Input data length in bytes
521   * @mic: Buffer for the computed MIC, eap_gpsk_mic_len(cipher) bytes
522   * Returns: 0 on success, -1 on failure
523   */
eap_gpsk_compute_mic(const u8 * sk,size_t sk_len,int vendor,int specifier,const u8 * data,size_t len,u8 * mic)524  int eap_gpsk_compute_mic(const u8 *sk, size_t sk_len, int vendor,
525  			 int specifier, const u8 *data, size_t len, u8 *mic)
526  {
527  	int ret;
528  
529  	if (vendor != EAP_GPSK_VENDOR_IETF)
530  		return -1;
531  
532  	switch (specifier) {
533  	case EAP_GPSK_CIPHER_AES:
534  		ret = eap_gpsk_compute_mic_aes(sk, sk_len, data, len, mic);
535  		break;
536  #ifdef EAP_GPSK_SHA256
537  	case EAP_GPSK_CIPHER_SHA256:
538  		ret = hmac_sha256(sk, sk_len, data, len, mic);
539  		break;
540  #endif /* EAP_GPSK_SHA256 */
541  	default:
542  		wpa_printf(MSG_DEBUG, "EAP-GPSK: Unknown cipher %d:%d used in "
543  			   "MIC computation", vendor, specifier);
544  		ret = -1;
545  		break;
546  	}
547  
548  	if (ret)
549  		wpa_printf(MSG_DEBUG, "EAP-GPSK: Could not compute MIC");
550  
551  	return ret;
552  }
553