1 /*
2  * EAP peer method: EAP-MD5 (RFC 3748 and RFC 1994)
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 "eap_i.h"
13 #include "eap_common/chap.h"
14 
15 
16 static void * eap_md5_init(struct eap_sm *sm)
17 {
18 	/* No need for private data. However, must return non-NULL to indicate
19 	 * success. */
20 	return (void *) 1;
21 }
22 
23 
24 static void eap_md5_deinit(struct eap_sm *sm, void *priv)
25 {
26 }
27 
28 
29 static struct wpabuf * eap_md5_process(struct eap_sm *sm, void *priv,
30 				       struct eap_method_ret *ret,
31 				       const struct wpabuf *reqData)
32 {
33 	struct wpabuf *resp;
34 	const u8 *pos, *challenge, *password;
35 	u8 *rpos, id;
36 	size_t len, challenge_len, password_len;
37 
38 	password = eap_get_config_password(sm, &password_len);
39 	if (password == NULL) {
40 		wpa_printf(MSG_INFO, "EAP-MD5: Password not configured");
41 		eap_sm_request_password(sm);
42 		ret->ignore = TRUE;
43 		return NULL;
44 	}
45 
46 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_MD5, reqData, &len);
47 	if (pos == NULL || len == 0) {
48 		wpa_printf(MSG_INFO, "EAP-MD5: Invalid frame (pos=%p len=%lu)",
49 			   pos, (unsigned long) len);
50 		ret->ignore = TRUE;
51 		return NULL;
52 	}
53 
54 	/*
55 	 * CHAP Challenge:
56 	 * Value-Size (1 octet) | Value(Challenge) | Name(optional)
57 	 */
58 	challenge_len = *pos++;
59 	if (challenge_len == 0 || challenge_len > len - 1) {
60 		wpa_printf(MSG_INFO, "EAP-MD5: Invalid challenge "
61 			   "(challenge_len=%lu len=%lu)",
62 			   (unsigned long) challenge_len, (unsigned long) len);
63 		ret->ignore = TRUE;
64 		return NULL;
65 	}
66 	ret->ignore = FALSE;
67 	challenge = pos;
68 	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Challenge",
69 		    challenge, challenge_len);
70 
71 	wpa_printf(MSG_DEBUG, "EAP-MD5: Generating Challenge Response");
72 	ret->methodState = METHOD_DONE;
73 	ret->decision = DECISION_COND_SUCC;
74 	ret->allowNotifications = TRUE;
75 
76 	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_MD5, 1 + CHAP_MD5_LEN,
77 			     EAP_CODE_RESPONSE, eap_get_id(reqData));
78 	if (resp == NULL)
79 		return NULL;
80 
81 	/*
82 	 * CHAP Response:
83 	 * Value-Size (1 octet) | Value(Response) | Name(optional)
84 	 */
85 	wpabuf_put_u8(resp, CHAP_MD5_LEN);
86 
87 	id = eap_get_id(resp);
88 	rpos = wpabuf_put(resp, CHAP_MD5_LEN);
89 	if (chap_md5(id, password, password_len, challenge, challenge_len,
90 		     rpos)) {
91 		wpa_printf(MSG_INFO, "EAP-MD5: CHAP MD5 operation failed");
92 		ret->ignore = TRUE;
93 		wpabuf_free(resp);
94 		return NULL;
95 	}
96 	wpa_hexdump(MSG_MSGDUMP, "EAP-MD5: Response", rpos, CHAP_MD5_LEN);
97 
98 	return resp;
99 }
100 
101 
102 int eap_peer_md5_register(void)
103 {
104 	struct eap_method *eap;
105 	int ret;
106 
107 	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
108 				    EAP_VENDOR_IETF, EAP_TYPE_MD5, "MD5");
109 	if (eap == NULL)
110 		return -1;
111 
112 	eap->init = eap_md5_init;
113 	eap->deinit = eap_md5_deinit;
114 	eap->process = eap_md5_process;
115 
116 	ret = eap_peer_method_register(eap);
117 	if (ret)
118 		eap_peer_method_free(eap);
119 	return ret;
120 }
121