1 /*
2  * hostapd / EAP-MD5 server
3  * Copyright (c) 2004-2012, 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/random.h"
13 #include "eap_i.h"
14 #include "eap_common/chap.h"
15 
16 
17 #define CHALLENGE_LEN 16
18 
19 struct eap_md5_data {
20 	u8 challenge[CHALLENGE_LEN];
21 	enum { CONTINUE, SUCCESS, FAILURE } state;
22 };
23 
24 
25 static void * eap_md5_init(struct eap_sm *sm)
26 {
27 	struct eap_md5_data *data;
28 
29 	data = os_zalloc(sizeof(*data));
30 	if (data == NULL)
31 		return NULL;
32 	data->state = CONTINUE;
33 
34 	return data;
35 }
36 
37 
38 static void eap_md5_reset(struct eap_sm *sm, void *priv)
39 {
40 	struct eap_md5_data *data = priv;
41 	os_free(data);
42 }
43 
44 
45 static struct wpabuf * eap_md5_buildReq(struct eap_sm *sm, void *priv, u8 id)
46 {
47 	struct eap_md5_data *data = priv;
48 	struct wpabuf *req;
49 
50 	if (random_get_bytes(data->challenge, CHALLENGE_LEN)) {
51 		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to get random data");
52 		data->state = FAILURE;
53 		return NULL;
54 	}
55 
56 	req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MD5, 1 + CHALLENGE_LEN,
57 			    EAP_CODE_REQUEST, id);
58 	if (req == NULL) {
59 		wpa_printf(MSG_ERROR, "EAP-MD5: Failed to allocate memory for "
60 			   "request");
61 		data->state = FAILURE;
62 		return NULL;
63 	}
64 
65 	wpabuf_put_u8(req, CHALLENGE_LEN);
66 	wpabuf_put_data(req, data->challenge, CHALLENGE_LEN);
67 	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Challenge", data->challenge,
68 		    CHALLENGE_LEN);
69 
70 	data->state = CONTINUE;
71 
72 	return req;
73 }
74 
75 
76 static Boolean eap_md5_check(struct eap_sm *sm, void *priv,
77 			     struct wpabuf *respData)
78 {
79 	const u8 *pos;
80 	size_t len;
81 
82 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &len);
83 	if (pos == NULL || len < 1) {
84 		wpa_printf(MSG_INFO, "EAP-MD5: Invalid frame");
85 		return TRUE;
86 	}
87 	if (*pos != CHAP_MD5_LEN || 1 + CHAP_MD5_LEN > len) {
88 		wpa_printf(MSG_INFO, "EAP-MD5: Invalid response "
89 			   "(response_len=%d payload_len=%lu",
90 			   *pos, (unsigned long) len);
91 		return TRUE;
92 	}
93 
94 	return FALSE;
95 }
96 
97 
98 static void eap_md5_process(struct eap_sm *sm, void *priv,
99 			    struct wpabuf *respData)
100 {
101 	struct eap_md5_data *data = priv;
102 	const u8 *pos;
103 	size_t plen;
104 	u8 hash[CHAP_MD5_LEN], id;
105 
106 	if (sm->user == NULL || sm->user->password == NULL ||
107 	    sm->user->password_hash) {
108 		wpa_printf(MSG_INFO, "EAP-MD5: Plaintext password not "
109 			   "configured");
110 		data->state = FAILURE;
111 		return;
112 	}
113 
114 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, respData, &plen);
115 	if (pos == NULL || *pos != CHAP_MD5_LEN || plen < 1 + CHAP_MD5_LEN)
116 		return; /* Should not happen - frame already validated */
117 
118 	pos++; /* Skip response len */
119 	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Response", pos, CHAP_MD5_LEN);
120 
121 	id = eap_get_id(respData);
122 	if (chap_md5(id, sm->user->password, sm->user->password_len,
123 		     data->challenge, CHALLENGE_LEN, hash)) {
124 		wpa_printf(MSG_INFO, "EAP-MD5: CHAP MD5 operation failed");
125 		data->state = FAILURE;
126 		return;
127 	}
128 
129 	if (os_memcmp_const(hash, pos, CHAP_MD5_LEN) == 0) {
130 		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Success");
131 		data->state = SUCCESS;
132 	} else {
133 		wpa_printf(MSG_DEBUG, "EAP-MD5: Done - Failure");
134 		data->state = FAILURE;
135 	}
136 }
137 
138 
139 static Boolean eap_md5_isDone(struct eap_sm *sm, void *priv)
140 {
141 	struct eap_md5_data *data = priv;
142 	return data->state != CONTINUE;
143 }
144 
145 
146 static Boolean eap_md5_isSuccess(struct eap_sm *sm, void *priv)
147 {
148 	struct eap_md5_data *data = priv;
149 	return data->state == SUCCESS;
150 }
151 
152 
153 int eap_server_md5_register(void)
154 {
155 	struct eap_method *eap;
156 
157 	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
158 				      EAP_VENDOR_IETF, EAP_TYPE_MD5, "MD5");
159 	if (eap == NULL)
160 		return -1;
161 
162 	eap->init = eap_md5_init;
163 	eap->reset = eap_md5_reset;
164 	eap->buildReq = eap_md5_buildReq;
165 	eap->check = eap_md5_check;
166 	eap->process = eap_md5_process;
167 	eap->isDone = eap_md5_isDone;
168 	eap->isSuccess = eap_md5_isSuccess;
169 
170 	return eap_server_method_register(eap);
171 }
172