hmsniff: add two more message types
[hmcfgusb] / hm.c
1 /* HomeMatic protocol-functions
2 *
3 * Copyright (c) 2014-16 Michael Gernoth <michael@gernoth.net>
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a copy
6 * of this software and associated documentation files (the "Software"), to
7 * deal in the Software without restriction, including without limitation the
8 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
9 * sell copies of the Software, and to permit persons to whom the Software is
10 * furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <unistd.h>
27 #include <stdint.h>
28 #include <string.h>
29 #include <strings.h>
30 #include <errno.h>
31 #include <sys/types.h>
32 #include <sys/time.h>
33
34 #include "aes.h"
35 #include "hexdump.h"
36 #include "hm.h"
37
38 static int debug = 0;
39
40 uint8_t* hm_sign(uint8_t *key, uint8_t *challenge, uint8_t *m_frame, uint8_t *exp_auth, uint8_t *resp)
41 {
42 uint8_t signkey[16];
43 WORD ks[60];
44 struct timeval tv;
45 int i;
46
47 printf("AES-request with challenge: %02x%02x%02x%02x%02x%02x\n",
48 challenge[0], challenge[1], challenge[2],
49 challenge[3], challenge[4], challenge[5]);
50
51 /*
52 * Build signing key by XORing the first 6 bytes of
53 * the key with the challenge.
54 */
55 memcpy(signkey, key, sizeof(signkey));
56 for (i = 0; i < 6; i++) {
57 signkey[i] ^= challenge[i];
58 }
59 aes_key_setup(signkey, ks, 128);
60
61 /*
62 * Generate payload for first encryption.
63 */
64 gettimeofday(&tv, NULL);
65 resp[0] = tv.tv_sec >> 24 & 0xff;
66 resp[1] = tv.tv_sec >> 16 & 0xff;
67 resp[2] = tv.tv_sec >> 8 & 0xff;
68 resp[3] = tv.tv_sec & 0xff;
69 resp[4] = tv.tv_usec >> 8 & 0xff;
70 resp[5] = tv.tv_usec & 0xff;
71 memcpy(&(resp[6]), &(m_frame[MSGID]), 10);
72
73 if (debug)
74 hexdump(resp, 16, "P > ");
75
76 aes_encrypt(resp, resp, ks, 128);
77
78 if (debug)
79 hexdump(resp, 16, "Pe > ");
80
81 /*
82 * Device has to answer with the first 4 bytes of the
83 * encrypted payload to authenticate, so pass them to
84 * the caller.
85 */
86
87 if (exp_auth) {
88 memcpy(exp_auth, resp, 4);
89 }
90
91 /*
92 * XOR parameters of the m_frame to the payload.
93 */
94 for (i = 0; i < PAYLOADLEN(m_frame) - 1; i++) {
95 if (i == 16) {
96 break;
97 }
98
99 resp[i] ^= m_frame[PAYLOAD + 1 + i];
100 }
101
102 if (debug)
103 hexdump(resp, 16, "Pe^ > ");
104
105 /*
106 * Encrypt payload again
107 */
108 aes_encrypt(resp, resp, ks, 128);
109
110 if (debug)
111 hexdump(resp, 16, "Pe^e> ");
112
113 return resp;
114 }
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