1*5d5fbe79SDavid van Moolenbroek /**
2*5d5fbe79SDavid van Moolenbroek * @file
3*5d5fbe79SDavid van Moolenbroek * SNMPv3 crypto/auth functions implemented for ARM mbedtls.
4*5d5fbe79SDavid van Moolenbroek */
5*5d5fbe79SDavid van Moolenbroek
6*5d5fbe79SDavid van Moolenbroek /*
7*5d5fbe79SDavid van Moolenbroek * Copyright (c) 2016 Elias Oenal and Dirk Ziegelmeier.
8*5d5fbe79SDavid van Moolenbroek * All rights reserved.
9*5d5fbe79SDavid van Moolenbroek *
10*5d5fbe79SDavid van Moolenbroek * Redistribution and use in source and binary forms, with or without modification,
11*5d5fbe79SDavid van Moolenbroek * are permitted provided that the following conditions are met:
12*5d5fbe79SDavid van Moolenbroek *
13*5d5fbe79SDavid van Moolenbroek * 1. Redistributions of source code must retain the above copyright notice,
14*5d5fbe79SDavid van Moolenbroek * this list of conditions and the following disclaimer.
15*5d5fbe79SDavid van Moolenbroek * 2. Redistributions in binary form must reproduce the above copyright notice,
16*5d5fbe79SDavid van Moolenbroek * this list of conditions and the following disclaimer in the documentation
17*5d5fbe79SDavid van Moolenbroek * and/or other materials provided with the distribution.
18*5d5fbe79SDavid van Moolenbroek * 3. The name of the author may not be used to endorse or promote products
19*5d5fbe79SDavid van Moolenbroek * derived from this software without specific prior written permission.
20*5d5fbe79SDavid van Moolenbroek *
21*5d5fbe79SDavid van Moolenbroek * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
22*5d5fbe79SDavid van Moolenbroek * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23*5d5fbe79SDavid van Moolenbroek * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
24*5d5fbe79SDavid van Moolenbroek * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25*5d5fbe79SDavid van Moolenbroek * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
26*5d5fbe79SDavid van Moolenbroek * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27*5d5fbe79SDavid van Moolenbroek * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28*5d5fbe79SDavid van Moolenbroek * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
29*5d5fbe79SDavid van Moolenbroek * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
30*5d5fbe79SDavid van Moolenbroek * OF SUCH DAMAGE.
31*5d5fbe79SDavid van Moolenbroek *
32*5d5fbe79SDavid van Moolenbroek * Author: Elias Oenal <lwip@eliasoenal.com>
33*5d5fbe79SDavid van Moolenbroek * Dirk Ziegelmeier <dirk@ziegelmeier.net>
34*5d5fbe79SDavid van Moolenbroek */
35*5d5fbe79SDavid van Moolenbroek
36*5d5fbe79SDavid van Moolenbroek #include "lwip/apps/snmpv3.h"
37*5d5fbe79SDavid van Moolenbroek #include "snmpv3_priv.h"
38*5d5fbe79SDavid van Moolenbroek #include "lwip/arch.h"
39*5d5fbe79SDavid van Moolenbroek #include "snmp_msg.h"
40*5d5fbe79SDavid van Moolenbroek #include "lwip/sys.h"
41*5d5fbe79SDavid van Moolenbroek #include <string.h>
42*5d5fbe79SDavid van Moolenbroek
43*5d5fbe79SDavid van Moolenbroek #if LWIP_SNMP && LWIP_SNMP_V3 && LWIP_SNMP_V3_MBEDTLS
44*5d5fbe79SDavid van Moolenbroek
45*5d5fbe79SDavid van Moolenbroek #include "mbedtls/md.h"
46*5d5fbe79SDavid van Moolenbroek #include "mbedtls/cipher.h"
47*5d5fbe79SDavid van Moolenbroek
48*5d5fbe79SDavid van Moolenbroek #include "mbedtls/md5.h"
49*5d5fbe79SDavid van Moolenbroek #include "mbedtls/sha1.h"
50*5d5fbe79SDavid van Moolenbroek
51*5d5fbe79SDavid van Moolenbroek err_t
snmpv3_auth(struct snmp_pbuf_stream * stream,u16_t length,const u8_t * key,snmpv3_auth_algo_t algo,u8_t * hmac_out)52*5d5fbe79SDavid van Moolenbroek snmpv3_auth(struct snmp_pbuf_stream* stream, u16_t length,
53*5d5fbe79SDavid van Moolenbroek const u8_t* key, snmpv3_auth_algo_t algo, u8_t* hmac_out)
54*5d5fbe79SDavid van Moolenbroek {
55*5d5fbe79SDavid van Moolenbroek u32_t i;
56*5d5fbe79SDavid van Moolenbroek u8_t key_len;
57*5d5fbe79SDavid van Moolenbroek const mbedtls_md_info_t *md_info;
58*5d5fbe79SDavid van Moolenbroek mbedtls_md_context_t ctx;
59*5d5fbe79SDavid van Moolenbroek struct snmp_pbuf_stream read_stream;
60*5d5fbe79SDavid van Moolenbroek snmp_pbuf_stream_init(&read_stream, stream->pbuf, stream->offset, stream->length);
61*5d5fbe79SDavid van Moolenbroek
62*5d5fbe79SDavid van Moolenbroek if (algo == SNMP_V3_AUTH_ALGO_MD5) {
63*5d5fbe79SDavid van Moolenbroek md_info = mbedtls_md_info_from_type(MBEDTLS_MD_MD5);
64*5d5fbe79SDavid van Moolenbroek key_len = SNMP_V3_MD5_LEN;
65*5d5fbe79SDavid van Moolenbroek } else if (algo == SNMP_V3_AUTH_ALGO_SHA) {
66*5d5fbe79SDavid van Moolenbroek md_info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA1);
67*5d5fbe79SDavid van Moolenbroek key_len = SNMP_V3_SHA_LEN;
68*5d5fbe79SDavid van Moolenbroek } else {
69*5d5fbe79SDavid van Moolenbroek return ERR_ARG;
70*5d5fbe79SDavid van Moolenbroek }
71*5d5fbe79SDavid van Moolenbroek
72*5d5fbe79SDavid van Moolenbroek mbedtls_md_init(&ctx);
73*5d5fbe79SDavid van Moolenbroek if(mbedtls_md_setup(&ctx, md_info, 1) != 0) {
74*5d5fbe79SDavid van Moolenbroek return ERR_ARG;
75*5d5fbe79SDavid van Moolenbroek }
76*5d5fbe79SDavid van Moolenbroek
77*5d5fbe79SDavid van Moolenbroek if (mbedtls_md_hmac_starts(&ctx, key, key_len) != 0) {
78*5d5fbe79SDavid van Moolenbroek goto free_md;
79*5d5fbe79SDavid van Moolenbroek }
80*5d5fbe79SDavid van Moolenbroek
81*5d5fbe79SDavid van Moolenbroek for (i = 0; i < length; i++) {
82*5d5fbe79SDavid van Moolenbroek u8_t byte;
83*5d5fbe79SDavid van Moolenbroek
84*5d5fbe79SDavid van Moolenbroek if (snmp_pbuf_stream_read(&read_stream, &byte)) {
85*5d5fbe79SDavid van Moolenbroek goto free_md;
86*5d5fbe79SDavid van Moolenbroek }
87*5d5fbe79SDavid van Moolenbroek
88*5d5fbe79SDavid van Moolenbroek if (mbedtls_md_hmac_update(&ctx, &byte, 1) != 0) {
89*5d5fbe79SDavid van Moolenbroek goto free_md;
90*5d5fbe79SDavid van Moolenbroek }
91*5d5fbe79SDavid van Moolenbroek }
92*5d5fbe79SDavid van Moolenbroek
93*5d5fbe79SDavid van Moolenbroek if (mbedtls_md_hmac_finish(&ctx, hmac_out) != 0) {
94*5d5fbe79SDavid van Moolenbroek goto free_md;
95*5d5fbe79SDavid van Moolenbroek }
96*5d5fbe79SDavid van Moolenbroek
97*5d5fbe79SDavid van Moolenbroek mbedtls_md_free(&ctx);
98*5d5fbe79SDavid van Moolenbroek return ERR_OK;
99*5d5fbe79SDavid van Moolenbroek
100*5d5fbe79SDavid van Moolenbroek free_md:
101*5d5fbe79SDavid van Moolenbroek mbedtls_md_free(&ctx);
102*5d5fbe79SDavid van Moolenbroek return ERR_ARG;
103*5d5fbe79SDavid van Moolenbroek }
104*5d5fbe79SDavid van Moolenbroek
105*5d5fbe79SDavid van Moolenbroek #if LWIP_SNMP_V3_CRYPTO
106*5d5fbe79SDavid van Moolenbroek
107*5d5fbe79SDavid van Moolenbroek err_t
snmpv3_crypt(struct snmp_pbuf_stream * stream,u16_t length,const u8_t * key,const u8_t * priv_param,const u32_t engine_boots,const u32_t engine_time,snmpv3_priv_algo_t algo,snmpv3_priv_mode_t mode)108*5d5fbe79SDavid van Moolenbroek snmpv3_crypt(struct snmp_pbuf_stream* stream, u16_t length,
109*5d5fbe79SDavid van Moolenbroek const u8_t* key, const u8_t* priv_param, const u32_t engine_boots,
110*5d5fbe79SDavid van Moolenbroek const u32_t engine_time, snmpv3_priv_algo_t algo, snmpv3_priv_mode_t mode)
111*5d5fbe79SDavid van Moolenbroek {
112*5d5fbe79SDavid van Moolenbroek size_t i;
113*5d5fbe79SDavid van Moolenbroek mbedtls_cipher_context_t ctx;
114*5d5fbe79SDavid van Moolenbroek const mbedtls_cipher_info_t *cipher_info;
115*5d5fbe79SDavid van Moolenbroek
116*5d5fbe79SDavid van Moolenbroek struct snmp_pbuf_stream read_stream;
117*5d5fbe79SDavid van Moolenbroek struct snmp_pbuf_stream write_stream;
118*5d5fbe79SDavid van Moolenbroek snmp_pbuf_stream_init(&read_stream, stream->pbuf, stream->offset, stream->length);
119*5d5fbe79SDavid van Moolenbroek snmp_pbuf_stream_init(&write_stream, stream->pbuf, stream->offset, stream->length);
120*5d5fbe79SDavid van Moolenbroek mbedtls_cipher_init(&ctx);
121*5d5fbe79SDavid van Moolenbroek
122*5d5fbe79SDavid van Moolenbroek if (algo == SNMP_V3_PRIV_ALGO_DES) {
123*5d5fbe79SDavid van Moolenbroek u8_t iv_local[8];
124*5d5fbe79SDavid van Moolenbroek u8_t out_bytes[8];
125*5d5fbe79SDavid van Moolenbroek size_t out_len;
126*5d5fbe79SDavid van Moolenbroek
127*5d5fbe79SDavid van Moolenbroek /* RFC 3414 mandates padding for DES */
128*5d5fbe79SDavid van Moolenbroek if ((length & 0x07) != 0) {
129*5d5fbe79SDavid van Moolenbroek return ERR_ARG;
130*5d5fbe79SDavid van Moolenbroek }
131*5d5fbe79SDavid van Moolenbroek
132*5d5fbe79SDavid van Moolenbroek cipher_info = mbedtls_cipher_info_from_type(MBEDTLS_CIPHER_DES_CBC);
133*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_setup(&ctx, cipher_info) != 0) {
134*5d5fbe79SDavid van Moolenbroek return ERR_ARG;
135*5d5fbe79SDavid van Moolenbroek }
136*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_set_padding_mode(&ctx, MBEDTLS_PADDING_NONE) != 0) {
137*5d5fbe79SDavid van Moolenbroek return ERR_ARG;
138*5d5fbe79SDavid van Moolenbroek }
139*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_setkey(&ctx, key, 8*8, (mode == SNMP_V3_PRIV_MODE_ENCRYPT)? MBEDTLS_ENCRYPT : MBEDTLS_DECRYPT) != 0) {
140*5d5fbe79SDavid van Moolenbroek goto error;
141*5d5fbe79SDavid van Moolenbroek }
142*5d5fbe79SDavid van Moolenbroek
143*5d5fbe79SDavid van Moolenbroek /* Prepare IV */
144*5d5fbe79SDavid van Moolenbroek for (i = 0; i < LWIP_ARRAYSIZE(iv_local); i++) {
145*5d5fbe79SDavid van Moolenbroek iv_local[i] = priv_param[i] ^ key[i + 8];
146*5d5fbe79SDavid van Moolenbroek }
147*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_set_iv(&ctx, iv_local, LWIP_ARRAYSIZE(iv_local)) != 0) {
148*5d5fbe79SDavid van Moolenbroek goto error;
149*5d5fbe79SDavid van Moolenbroek }
150*5d5fbe79SDavid van Moolenbroek
151*5d5fbe79SDavid van Moolenbroek for (i = 0; i < length; i += 8) {
152*5d5fbe79SDavid van Moolenbroek size_t j;
153*5d5fbe79SDavid van Moolenbroek u8_t in_bytes[8];
154*5d5fbe79SDavid van Moolenbroek out_len = LWIP_ARRAYSIZE(out_bytes) ;
155*5d5fbe79SDavid van Moolenbroek
156*5d5fbe79SDavid van Moolenbroek for (j = 0; j < LWIP_ARRAYSIZE(in_bytes); j++) {
157*5d5fbe79SDavid van Moolenbroek snmp_pbuf_stream_read(&read_stream, &in_bytes[j]);
158*5d5fbe79SDavid van Moolenbroek }
159*5d5fbe79SDavid van Moolenbroek
160*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_update(&ctx, in_bytes, LWIP_ARRAYSIZE(in_bytes), out_bytes, &out_len) != 0) {
161*5d5fbe79SDavid van Moolenbroek goto error;
162*5d5fbe79SDavid van Moolenbroek }
163*5d5fbe79SDavid van Moolenbroek
164*5d5fbe79SDavid van Moolenbroek snmp_pbuf_stream_writebuf(&write_stream, out_bytes, (u16_t)out_len);
165*5d5fbe79SDavid van Moolenbroek }
166*5d5fbe79SDavid van Moolenbroek
167*5d5fbe79SDavid van Moolenbroek out_len = LWIP_ARRAYSIZE(out_bytes);
168*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_finish(&ctx, out_bytes, &out_len) != 0) {
169*5d5fbe79SDavid van Moolenbroek goto error;
170*5d5fbe79SDavid van Moolenbroek }
171*5d5fbe79SDavid van Moolenbroek snmp_pbuf_stream_writebuf(&write_stream, out_bytes, (u16_t)out_len);
172*5d5fbe79SDavid van Moolenbroek } else if (algo == SNMP_V3_PRIV_ALGO_AES) {
173*5d5fbe79SDavid van Moolenbroek u8_t iv_local[16];
174*5d5fbe79SDavid van Moolenbroek
175*5d5fbe79SDavid van Moolenbroek cipher_info = mbedtls_cipher_info_from_type(MBEDTLS_CIPHER_AES_128_CFB128);
176*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_setup(&ctx, cipher_info) != 0) {
177*5d5fbe79SDavid van Moolenbroek return ERR_ARG;
178*5d5fbe79SDavid van Moolenbroek }
179*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_setkey(&ctx, key, 16*8, (mode == SNMP_V3_PRIV_MODE_ENCRYPT)? MBEDTLS_ENCRYPT : MBEDTLS_DECRYPT) != 0) {
180*5d5fbe79SDavid van Moolenbroek goto error;
181*5d5fbe79SDavid van Moolenbroek }
182*5d5fbe79SDavid van Moolenbroek
183*5d5fbe79SDavid van Moolenbroek /*
184*5d5fbe79SDavid van Moolenbroek * IV is the big endian concatenation of boots,
185*5d5fbe79SDavid van Moolenbroek * uptime and priv param - see RFC3826.
186*5d5fbe79SDavid van Moolenbroek */
187*5d5fbe79SDavid van Moolenbroek iv_local[0 + 0] = (engine_boots >> 24) & 0xFF;
188*5d5fbe79SDavid van Moolenbroek iv_local[0 + 1] = (engine_boots >> 16) & 0xFF;
189*5d5fbe79SDavid van Moolenbroek iv_local[0 + 2] = (engine_boots >> 8) & 0xFF;
190*5d5fbe79SDavid van Moolenbroek iv_local[0 + 3] = (engine_boots >> 0) & 0xFF;
191*5d5fbe79SDavid van Moolenbroek iv_local[4 + 0] = (engine_time >> 24) & 0xFF;
192*5d5fbe79SDavid van Moolenbroek iv_local[4 + 1] = (engine_time >> 16) & 0xFF;
193*5d5fbe79SDavid van Moolenbroek iv_local[4 + 2] = (engine_time >> 8) & 0xFF;
194*5d5fbe79SDavid van Moolenbroek iv_local[4 + 3] = (engine_time >> 0) & 0xFF;
195*5d5fbe79SDavid van Moolenbroek SMEMCPY(iv_local + 8, priv_param, 8);
196*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_set_iv(&ctx, iv_local, LWIP_ARRAYSIZE(iv_local)) != 0) {
197*5d5fbe79SDavid van Moolenbroek goto error;
198*5d5fbe79SDavid van Moolenbroek }
199*5d5fbe79SDavid van Moolenbroek
200*5d5fbe79SDavid van Moolenbroek for (i = 0; i < length; i++) {
201*5d5fbe79SDavid van Moolenbroek u8_t in_byte;
202*5d5fbe79SDavid van Moolenbroek u8_t out_byte;
203*5d5fbe79SDavid van Moolenbroek size_t out_len = sizeof(out_byte);
204*5d5fbe79SDavid van Moolenbroek
205*5d5fbe79SDavid van Moolenbroek snmp_pbuf_stream_read(&read_stream, &in_byte);
206*5d5fbe79SDavid van Moolenbroek if(mbedtls_cipher_update(&ctx, &in_byte, sizeof(in_byte), &out_byte, &out_len) != 0) {
207*5d5fbe79SDavid van Moolenbroek goto error;
208*5d5fbe79SDavid van Moolenbroek }
209*5d5fbe79SDavid van Moolenbroek snmp_pbuf_stream_write(&write_stream, out_byte);
210*5d5fbe79SDavid van Moolenbroek }
211*5d5fbe79SDavid van Moolenbroek } else {
212*5d5fbe79SDavid van Moolenbroek return ERR_ARG;
213*5d5fbe79SDavid van Moolenbroek }
214*5d5fbe79SDavid van Moolenbroek
215*5d5fbe79SDavid van Moolenbroek mbedtls_cipher_free(&ctx);
216*5d5fbe79SDavid van Moolenbroek return ERR_OK;
217*5d5fbe79SDavid van Moolenbroek
218*5d5fbe79SDavid van Moolenbroek error:
219*5d5fbe79SDavid van Moolenbroek mbedtls_cipher_free(&ctx);
220*5d5fbe79SDavid van Moolenbroek return ERR_OK;
221*5d5fbe79SDavid van Moolenbroek }
222*5d5fbe79SDavid van Moolenbroek
223*5d5fbe79SDavid van Moolenbroek #endif /* LWIP_SNMP_V3_CRYPTO */
224*5d5fbe79SDavid van Moolenbroek
225*5d5fbe79SDavid van Moolenbroek /* A.2.1. Password to Key Sample Code for MD5 */
226*5d5fbe79SDavid van Moolenbroek void
snmpv3_password_to_key_md5(const u8_t * password,size_t passwordlen,const u8_t * engineID,u8_t engineLength,u8_t * key)227*5d5fbe79SDavid van Moolenbroek snmpv3_password_to_key_md5(
228*5d5fbe79SDavid van Moolenbroek const u8_t *password, /* IN */
229*5d5fbe79SDavid van Moolenbroek size_t passwordlen, /* IN */
230*5d5fbe79SDavid van Moolenbroek const u8_t *engineID, /* IN - pointer to snmpEngineID */
231*5d5fbe79SDavid van Moolenbroek u8_t engineLength,/* IN - length of snmpEngineID */
232*5d5fbe79SDavid van Moolenbroek u8_t *key) /* OUT - pointer to caller 16-octet buffer */
233*5d5fbe79SDavid van Moolenbroek {
234*5d5fbe79SDavid van Moolenbroek mbedtls_md5_context MD;
235*5d5fbe79SDavid van Moolenbroek u8_t *cp, password_buf[64];
236*5d5fbe79SDavid van Moolenbroek u32_t password_index = 0;
237*5d5fbe79SDavid van Moolenbroek u8_t i;
238*5d5fbe79SDavid van Moolenbroek u32_t count = 0;
239*5d5fbe79SDavid van Moolenbroek
240*5d5fbe79SDavid van Moolenbroek mbedtls_md5_init(&MD); /* initialize MD5 */
241*5d5fbe79SDavid van Moolenbroek mbedtls_md5_starts(&MD);
242*5d5fbe79SDavid van Moolenbroek
243*5d5fbe79SDavid van Moolenbroek /**********************************************/
244*5d5fbe79SDavid van Moolenbroek /* Use while loop until we've done 1 Megabyte */
245*5d5fbe79SDavid van Moolenbroek /**********************************************/
246*5d5fbe79SDavid van Moolenbroek while (count < 1048576) {
247*5d5fbe79SDavid van Moolenbroek cp = password_buf;
248*5d5fbe79SDavid van Moolenbroek for (i = 0; i < 64; i++) {
249*5d5fbe79SDavid van Moolenbroek /*************************************************/
250*5d5fbe79SDavid van Moolenbroek /* Take the next octet of the password, wrapping */
251*5d5fbe79SDavid van Moolenbroek /* to the beginning of the password as necessary.*/
252*5d5fbe79SDavid van Moolenbroek /*************************************************/
253*5d5fbe79SDavid van Moolenbroek *cp++ = password[password_index++ % passwordlen];
254*5d5fbe79SDavid van Moolenbroek }
255*5d5fbe79SDavid van Moolenbroek mbedtls_md5_update(&MD, password_buf, 64);
256*5d5fbe79SDavid van Moolenbroek count += 64;
257*5d5fbe79SDavid van Moolenbroek }
258*5d5fbe79SDavid van Moolenbroek mbedtls_md5_finish(&MD, key); /* tell MD5 we're done */
259*5d5fbe79SDavid van Moolenbroek
260*5d5fbe79SDavid van Moolenbroek /*****************************************************/
261*5d5fbe79SDavid van Moolenbroek /* Now localize the key with the engineID and pass */
262*5d5fbe79SDavid van Moolenbroek /* through MD5 to produce final key */
263*5d5fbe79SDavid van Moolenbroek /* May want to ensure that engineLength <= 32, */
264*5d5fbe79SDavid van Moolenbroek /* otherwise need to use a buffer larger than 64 */
265*5d5fbe79SDavid van Moolenbroek /*****************************************************/
266*5d5fbe79SDavid van Moolenbroek SMEMCPY(password_buf, key, 16);
267*5d5fbe79SDavid van Moolenbroek MEMCPY(password_buf + 16, engineID, engineLength);
268*5d5fbe79SDavid van Moolenbroek SMEMCPY(password_buf + 16 + engineLength, key, 16);
269*5d5fbe79SDavid van Moolenbroek
270*5d5fbe79SDavid van Moolenbroek mbedtls_md5_starts(&MD);
271*5d5fbe79SDavid van Moolenbroek mbedtls_md5_update(&MD, password_buf, 32 + engineLength);
272*5d5fbe79SDavid van Moolenbroek mbedtls_md5_finish(&MD, key);
273*5d5fbe79SDavid van Moolenbroek
274*5d5fbe79SDavid van Moolenbroek mbedtls_md5_free(&MD);
275*5d5fbe79SDavid van Moolenbroek return;
276*5d5fbe79SDavid van Moolenbroek }
277*5d5fbe79SDavid van Moolenbroek
278*5d5fbe79SDavid van Moolenbroek /* A.2.2. Password to Key Sample Code for SHA */
279*5d5fbe79SDavid van Moolenbroek void
snmpv3_password_to_key_sha(const u8_t * password,size_t passwordlen,const u8_t * engineID,u8_t engineLength,u8_t * key)280*5d5fbe79SDavid van Moolenbroek snmpv3_password_to_key_sha(
281*5d5fbe79SDavid van Moolenbroek const u8_t *password, /* IN */
282*5d5fbe79SDavid van Moolenbroek size_t passwordlen, /* IN */
283*5d5fbe79SDavid van Moolenbroek const u8_t *engineID, /* IN - pointer to snmpEngineID */
284*5d5fbe79SDavid van Moolenbroek u8_t engineLength,/* IN - length of snmpEngineID */
285*5d5fbe79SDavid van Moolenbroek u8_t *key) /* OUT - pointer to caller 20-octet buffer */
286*5d5fbe79SDavid van Moolenbroek {
287*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_context SH;
288*5d5fbe79SDavid van Moolenbroek u8_t *cp, password_buf[72];
289*5d5fbe79SDavid van Moolenbroek u32_t password_index = 0;
290*5d5fbe79SDavid van Moolenbroek u8_t i;
291*5d5fbe79SDavid van Moolenbroek u32_t count = 0;
292*5d5fbe79SDavid van Moolenbroek
293*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_init(&SH); /* initialize SHA */
294*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_starts(&SH);
295*5d5fbe79SDavid van Moolenbroek
296*5d5fbe79SDavid van Moolenbroek /**********************************************/
297*5d5fbe79SDavid van Moolenbroek /* Use while loop until we've done 1 Megabyte */
298*5d5fbe79SDavid van Moolenbroek /**********************************************/
299*5d5fbe79SDavid van Moolenbroek while (count < 1048576) {
300*5d5fbe79SDavid van Moolenbroek cp = password_buf;
301*5d5fbe79SDavid van Moolenbroek for (i = 0; i < 64; i++) {
302*5d5fbe79SDavid van Moolenbroek /*************************************************/
303*5d5fbe79SDavid van Moolenbroek /* Take the next octet of the password, wrapping */
304*5d5fbe79SDavid van Moolenbroek /* to the beginning of the password as necessary.*/
305*5d5fbe79SDavid van Moolenbroek /*************************************************/
306*5d5fbe79SDavid van Moolenbroek *cp++ = password[password_index++ % passwordlen];
307*5d5fbe79SDavid van Moolenbroek }
308*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_update(&SH, password_buf, 64);
309*5d5fbe79SDavid van Moolenbroek count += 64;
310*5d5fbe79SDavid van Moolenbroek }
311*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_finish(&SH, key); /* tell SHA we're done */
312*5d5fbe79SDavid van Moolenbroek
313*5d5fbe79SDavid van Moolenbroek /*****************************************************/
314*5d5fbe79SDavid van Moolenbroek /* Now localize the key with the engineID and pass */
315*5d5fbe79SDavid van Moolenbroek /* through SHA to produce final key */
316*5d5fbe79SDavid van Moolenbroek /* May want to ensure that engineLength <= 32, */
317*5d5fbe79SDavid van Moolenbroek /* otherwise need to use a buffer larger than 72 */
318*5d5fbe79SDavid van Moolenbroek /*****************************************************/
319*5d5fbe79SDavid van Moolenbroek SMEMCPY(password_buf, key, 20);
320*5d5fbe79SDavid van Moolenbroek MEMCPY(password_buf + 20, engineID, engineLength);
321*5d5fbe79SDavid van Moolenbroek SMEMCPY(password_buf + 20 + engineLength, key, 20);
322*5d5fbe79SDavid van Moolenbroek
323*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_starts(&SH);
324*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_update(&SH, password_buf, 40 + engineLength);
325*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_finish(&SH, key);
326*5d5fbe79SDavid van Moolenbroek
327*5d5fbe79SDavid van Moolenbroek mbedtls_sha1_free(&SH);
328*5d5fbe79SDavid van Moolenbroek return;
329*5d5fbe79SDavid van Moolenbroek }
330*5d5fbe79SDavid van Moolenbroek
331*5d5fbe79SDavid van Moolenbroek #endif /* LWIP_SNMP && LWIP_SNMP_V3 && LWIP_SNMP_V3_MBEDTLS */
332