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features/FEATURE_LWIP/lwip-interface/lwip/src/apps/snmp/lwip_snmpv3_mbedtls.c@0:098463de4c5d, 2017-01-25 (annotated)

Committer:
group-onsemi
Date:
Wed Jan 25 20:34:15 2017 +0000
Revision:
0:098463de4c5d
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
group-onsemi 0:098463de4c5d 1 /**
group-onsemi 0:098463de4c5d 2 * @file
group-onsemi 0:098463de4c5d 3 * SNMPv3 crypto/auth functions implemented for ARM mbedtls.
group-onsemi 0:098463de4c5d 4 */
group-onsemi 0:098463de4c5d 5
group-onsemi 0:098463de4c5d 6 /*
group-onsemi 0:098463de4c5d 7 * Copyright (c) 2016 Elias Oenal and Dirk Ziegelmeier.
group-onsemi 0:098463de4c5d 8 * All rights reserved.
group-onsemi 0:098463de4c5d 9 *
group-onsemi 0:098463de4c5d 10 * Redistribution and use in source and binary forms, with or without modification,
group-onsemi 0:098463de4c5d 11 * are permitted provided that the following conditions are met:
group-onsemi 0:098463de4c5d 12 *
group-onsemi 0:098463de4c5d 13 * 1. Redistributions of source code must retain the above copyright notice,
group-onsemi 0:098463de4c5d 14 * this list of conditions and the following disclaimer.
group-onsemi 0:098463de4c5d 15 * 2. Redistributions in binary form must reproduce the above copyright notice,
group-onsemi 0:098463de4c5d 16 * this list of conditions and the following disclaimer in the documentation
group-onsemi 0:098463de4c5d 17 * and/or other materials provided with the distribution.
group-onsemi 0:098463de4c5d 18 * 3. The name of the author may not be used to endorse or promote products
group-onsemi 0:098463de4c5d 19 * derived from this software without specific prior written permission.
group-onsemi 0:098463de4c5d 20 *
group-onsemi 0:098463de4c5d 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
group-onsemi 0:098463de4c5d 22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
group-onsemi 0:098463de4c5d 23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
group-onsemi 0:098463de4c5d 24 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
group-onsemi 0:098463de4c5d 25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
group-onsemi 0:098463de4c5d 26 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
group-onsemi 0:098463de4c5d 27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
group-onsemi 0:098463de4c5d 28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
group-onsemi 0:098463de4c5d 29 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
group-onsemi 0:098463de4c5d 30 * OF SUCH DAMAGE.
group-onsemi 0:098463de4c5d 31 *
group-onsemi 0:098463de4c5d 32 * Author: Elias Oenal <lwip@eliasoenal.com>
group-onsemi 0:098463de4c5d 33 * Dirk Ziegelmeier <dirk@ziegelmeier.net>
group-onsemi 0:098463de4c5d 34 */
group-onsemi 0:098463de4c5d 35
group-onsemi 0:098463de4c5d 36 #include "lwip/apps/snmpv3.h"
group-onsemi 0:098463de4c5d 37 #include "snmpv3_priv.h"
group-onsemi 0:098463de4c5d 38 #include "lwip/arch.h"
group-onsemi 0:098463de4c5d 39 #include "snmp_msg.h"
group-onsemi 0:098463de4c5d 40 #include "lwip/sys.h"
group-onsemi 0:098463de4c5d 41 #include <string.h>
group-onsemi 0:098463de4c5d 42
group-onsemi 0:098463de4c5d 43 #if LWIP_SNMP && LWIP_SNMP_V3 && LWIP_SNMP_V3_MBEDTLS
group-onsemi 0:098463de4c5d 44
group-onsemi 0:098463de4c5d 45 #include "mbedtls/md.h"
group-onsemi 0:098463de4c5d 46 #include "mbedtls/cipher.h"
group-onsemi 0:098463de4c5d 47
group-onsemi 0:098463de4c5d 48 #include "mbedtls/md5.h"
group-onsemi 0:098463de4c5d 49 #include "mbedtls/sha1.h"
group-onsemi 0:098463de4c5d 50
group-onsemi 0:098463de4c5d 51 err_t
group-onsemi 0:098463de4c5d 52 snmpv3_auth(struct snmp_pbuf_stream* stream, u16_t length,
group-onsemi 0:098463de4c5d 53 const u8_t* key, u8_t algo, u8_t* hmac_out)
group-onsemi 0:098463de4c5d 54 {
group-onsemi 0:098463de4c5d 55 u32_t i;
group-onsemi 0:098463de4c5d 56 u8_t key_len;
group-onsemi 0:098463de4c5d 57 const mbedtls_md_info_t *md_info;
group-onsemi 0:098463de4c5d 58 mbedtls_md_context_t ctx;
group-onsemi 0:098463de4c5d 59 struct snmp_pbuf_stream read_stream;
group-onsemi 0:098463de4c5d 60 snmp_pbuf_stream_init(&read_stream, stream->pbuf, stream->offset, stream->length);
group-onsemi 0:098463de4c5d 61
group-onsemi 0:098463de4c5d 62 if (algo == SNMP_V3_AUTH_ALGO_MD5) {
group-onsemi 0:098463de4c5d 63 md_info = mbedtls_md_info_from_type(MBEDTLS_MD_MD5);
group-onsemi 0:098463de4c5d 64 key_len = SNMP_V3_MD5_LEN;
group-onsemi 0:098463de4c5d 65 } else if (algo == SNMP_V3_AUTH_ALGO_SHA) {
group-onsemi 0:098463de4c5d 66 md_info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA1);
group-onsemi 0:098463de4c5d 67 key_len = SNMP_V3_SHA_LEN;
group-onsemi 0:098463de4c5d 68 } else {
group-onsemi 0:098463de4c5d 69 return ERR_ARG;
group-onsemi 0:098463de4c5d 70 }
group-onsemi 0:098463de4c5d 71
group-onsemi 0:098463de4c5d 72 mbedtls_md_init(&ctx);
group-onsemi 0:098463de4c5d 73 if(mbedtls_md_setup(&ctx, md_info, 1) != 0) {
group-onsemi 0:098463de4c5d 74 return ERR_ARG;
group-onsemi 0:098463de4c5d 75 }
group-onsemi 0:098463de4c5d 76
group-onsemi 0:098463de4c5d 77 if (mbedtls_md_hmac_starts(&ctx, key, key_len) != 0) {
group-onsemi 0:098463de4c5d 78 goto free_md;
group-onsemi 0:098463de4c5d 79 }
group-onsemi 0:098463de4c5d 80
group-onsemi 0:098463de4c5d 81 for (i = 0; i < length; i++) {
group-onsemi 0:098463de4c5d 82 u8_t byte;
group-onsemi 0:098463de4c5d 83
group-onsemi 0:098463de4c5d 84 if (snmp_pbuf_stream_read(&read_stream, &byte)) {
group-onsemi 0:098463de4c5d 85 goto free_md;
group-onsemi 0:098463de4c5d 86 }
group-onsemi 0:098463de4c5d 87
group-onsemi 0:098463de4c5d 88 if (mbedtls_md_hmac_update(&ctx, &byte, 1) != 0) {
group-onsemi 0:098463de4c5d 89 goto free_md;
group-onsemi 0:098463de4c5d 90 }
group-onsemi 0:098463de4c5d 91 }
group-onsemi 0:098463de4c5d 92
group-onsemi 0:098463de4c5d 93 if (mbedtls_md_hmac_finish(&ctx, hmac_out) != 0) {
group-onsemi 0:098463de4c5d 94 goto free_md;
group-onsemi 0:098463de4c5d 95 }
group-onsemi 0:098463de4c5d 96
group-onsemi 0:098463de4c5d 97 mbedtls_md_free(&ctx);
group-onsemi 0:098463de4c5d 98 return ERR_OK;
group-onsemi 0:098463de4c5d 99
group-onsemi 0:098463de4c5d 100 free_md:
group-onsemi 0:098463de4c5d 101 mbedtls_md_free(&ctx);
group-onsemi 0:098463de4c5d 102 return ERR_ARG;
group-onsemi 0:098463de4c5d 103 }
group-onsemi 0:098463de4c5d 104
group-onsemi 0:098463de4c5d 105 #if LWIP_SNMP_V3_CRYPTO
group-onsemi 0:098463de4c5d 106
group-onsemi 0:098463de4c5d 107 err_t
group-onsemi 0:098463de4c5d 108 snmpv3_crypt(struct snmp_pbuf_stream* stream, u16_t length,
group-onsemi 0:098463de4c5d 109 const u8_t* key, const u8_t* priv_param, const u32_t engine_boots,
group-onsemi 0:098463de4c5d 110 const u32_t engine_time, u8_t algo, u8_t mode)
group-onsemi 0:098463de4c5d 111 {
group-onsemi 0:098463de4c5d 112 size_t i;
group-onsemi 0:098463de4c5d 113 mbedtls_cipher_context_t ctx;
group-onsemi 0:098463de4c5d 114 const mbedtls_cipher_info_t *cipher_info;
group-onsemi 0:098463de4c5d 115
group-onsemi 0:098463de4c5d 116 struct snmp_pbuf_stream read_stream;
group-onsemi 0:098463de4c5d 117 struct snmp_pbuf_stream write_stream;
group-onsemi 0:098463de4c5d 118 snmp_pbuf_stream_init(&read_stream, stream->pbuf, stream->offset, stream->length);
group-onsemi 0:098463de4c5d 119 snmp_pbuf_stream_init(&write_stream, stream->pbuf, stream->offset, stream->length);
group-onsemi 0:098463de4c5d 120 mbedtls_cipher_init(&ctx);
group-onsemi 0:098463de4c5d 121
group-onsemi 0:098463de4c5d 122 if (algo == SNMP_V3_PRIV_ALGO_DES) {
group-onsemi 0:098463de4c5d 123 u8_t iv_local[8];
group-onsemi 0:098463de4c5d 124 u8_t out_bytes[8];
group-onsemi 0:098463de4c5d 125 size_t out_len;
group-onsemi 0:098463de4c5d 126
group-onsemi 0:098463de4c5d 127 /* RFC 3414 mandates padding for DES */
group-onsemi 0:098463de4c5d 128 if ((length & 0x07) != 0) {
group-onsemi 0:098463de4c5d 129 return ERR_ARG;
group-onsemi 0:098463de4c5d 130 }
group-onsemi 0:098463de4c5d 131
group-onsemi 0:098463de4c5d 132 cipher_info = mbedtls_cipher_info_from_type(MBEDTLS_CIPHER_DES_CBC);
group-onsemi 0:098463de4c5d 133 if(mbedtls_cipher_setup(&ctx, cipher_info) != 0) {
group-onsemi 0:098463de4c5d 134 return ERR_ARG;
group-onsemi 0:098463de4c5d 135 }
group-onsemi 0:098463de4c5d 136 if(mbedtls_cipher_set_padding_mode(&ctx, MBEDTLS_PADDING_NONE) != 0) {
group-onsemi 0:098463de4c5d 137 return ERR_ARG;
group-onsemi 0:098463de4c5d 138 }
group-onsemi 0:098463de4c5d 139 if(mbedtls_cipher_setkey(&ctx, key, 8*8, (mode == SNMP_V3_PRIV_MODE_ENCRYPT)? MBEDTLS_ENCRYPT : MBEDTLS_DECRYPT) != 0) {
group-onsemi 0:098463de4c5d 140 goto error;
group-onsemi 0:098463de4c5d 141 }
group-onsemi 0:098463de4c5d 142
group-onsemi 0:098463de4c5d 143 /* Prepare IV */
group-onsemi 0:098463de4c5d 144 for (i = 0; i < LWIP_ARRAYSIZE(iv_local); i++) {
group-onsemi 0:098463de4c5d 145 iv_local[i] = priv_param[i] ^ key[i + 8];
group-onsemi 0:098463de4c5d 146 }
group-onsemi 0:098463de4c5d 147 if(mbedtls_cipher_set_iv(&ctx, iv_local, LWIP_ARRAYSIZE(iv_local)) != 0) {
group-onsemi 0:098463de4c5d 148 goto error;
group-onsemi 0:098463de4c5d 149 }
group-onsemi 0:098463de4c5d 150
group-onsemi 0:098463de4c5d 151 for (i = 0; i < length; i += 8) {
group-onsemi 0:098463de4c5d 152 size_t j;
group-onsemi 0:098463de4c5d 153 u8_t in_bytes[8];
group-onsemi 0:098463de4c5d 154 out_len = LWIP_ARRAYSIZE(out_bytes) ;
group-onsemi 0:098463de4c5d 155
group-onsemi 0:098463de4c5d 156 for (j = 0; j < LWIP_ARRAYSIZE(in_bytes); j++) {
group-onsemi 0:098463de4c5d 157 snmp_pbuf_stream_read(&read_stream, &in_bytes[j]);
group-onsemi 0:098463de4c5d 158 }
group-onsemi 0:098463de4c5d 159
group-onsemi 0:098463de4c5d 160 if(mbedtls_cipher_update(&ctx, in_bytes, LWIP_ARRAYSIZE(in_bytes), out_bytes, &out_len) != 0) {
group-onsemi 0:098463de4c5d 161 goto error;
group-onsemi 0:098463de4c5d 162 }
group-onsemi 0:098463de4c5d 163
group-onsemi 0:098463de4c5d 164 snmp_pbuf_stream_writebuf(&write_stream, out_bytes, out_len);
group-onsemi 0:098463de4c5d 165 }
group-onsemi 0:098463de4c5d 166
group-onsemi 0:098463de4c5d 167 out_len = LWIP_ARRAYSIZE(out_bytes);
group-onsemi 0:098463de4c5d 168 if(mbedtls_cipher_finish(&ctx, out_bytes, &out_len) != 0) {
group-onsemi 0:098463de4c5d 169 goto error;
group-onsemi 0:098463de4c5d 170 }
group-onsemi 0:098463de4c5d 171 snmp_pbuf_stream_writebuf(&write_stream, out_bytes, out_len);
group-onsemi 0:098463de4c5d 172 } else if (algo == SNMP_V3_PRIV_ALGO_AES) {
group-onsemi 0:098463de4c5d 173 u8_t iv_local[16];
group-onsemi 0:098463de4c5d 174
group-onsemi 0:098463de4c5d 175 cipher_info = mbedtls_cipher_info_from_type(MBEDTLS_CIPHER_AES_128_CFB128);
group-onsemi 0:098463de4c5d 176 if(mbedtls_cipher_setup(&ctx, cipher_info) != 0) {
group-onsemi 0:098463de4c5d 177 return ERR_ARG;
group-onsemi 0:098463de4c5d 178 }
group-onsemi 0:098463de4c5d 179 if(mbedtls_cipher_setkey(&ctx, key, 16*8, (mode == SNMP_V3_PRIV_MODE_ENCRYPT)? MBEDTLS_ENCRYPT : MBEDTLS_DECRYPT) != 0) {
group-onsemi 0:098463de4c5d 180 goto error;
group-onsemi 0:098463de4c5d 181 }
group-onsemi 0:098463de4c5d 182
group-onsemi 0:098463de4c5d 183 /*
group-onsemi 0:098463de4c5d 184 * IV is the big endian concatenation of boots,
group-onsemi 0:098463de4c5d 185 * uptime and priv param - see RFC3826.
group-onsemi 0:098463de4c5d 186 */
group-onsemi 0:098463de4c5d 187 iv_local[0 + 0] = (engine_boots >> 24) & 0xFF;
group-onsemi 0:098463de4c5d 188 iv_local[0 + 1] = (engine_boots >> 16) & 0xFF;
group-onsemi 0:098463de4c5d 189 iv_local[0 + 2] = (engine_boots >> 8) & 0xFF;
group-onsemi 0:098463de4c5d 190 iv_local[0 + 3] = (engine_boots >> 0) & 0xFF;
group-onsemi 0:098463de4c5d 191 iv_local[4 + 0] = (engine_time >> 24) & 0xFF;
group-onsemi 0:098463de4c5d 192 iv_local[4 + 1] = (engine_time >> 16) & 0xFF;
group-onsemi 0:098463de4c5d 193 iv_local[4 + 2] = (engine_time >> 8) & 0xFF;
group-onsemi 0:098463de4c5d 194 iv_local[4 + 3] = (engine_time >> 0) & 0xFF;
group-onsemi 0:098463de4c5d 195 memcpy(iv_local + 8, priv_param, 8);
group-onsemi 0:098463de4c5d 196 if(mbedtls_cipher_set_iv(&ctx, iv_local, LWIP_ARRAYSIZE(iv_local)) != 0) {
group-onsemi 0:098463de4c5d 197 goto error;
group-onsemi 0:098463de4c5d 198 }
group-onsemi 0:098463de4c5d 199
group-onsemi 0:098463de4c5d 200 for (i = 0; i < length; i++) {
group-onsemi 0:098463de4c5d 201 u8_t in_byte;
group-onsemi 0:098463de4c5d 202 u8_t out_byte;
group-onsemi 0:098463de4c5d 203 size_t out_len = sizeof(out_byte);
group-onsemi 0:098463de4c5d 204
group-onsemi 0:098463de4c5d 205 snmp_pbuf_stream_read(&read_stream, &in_byte);
group-onsemi 0:098463de4c5d 206 if(mbedtls_cipher_update(&ctx, &in_byte, sizeof(in_byte), &out_byte, &out_len) != 0) {
group-onsemi 0:098463de4c5d 207 goto error;
group-onsemi 0:098463de4c5d 208 }
group-onsemi 0:098463de4c5d 209 snmp_pbuf_stream_write(&write_stream, out_byte);
group-onsemi 0:098463de4c5d 210 }
group-onsemi 0:098463de4c5d 211 } else {
group-onsemi 0:098463de4c5d 212 return ERR_ARG;
group-onsemi 0:098463de4c5d 213 }
group-onsemi 0:098463de4c5d 214
group-onsemi 0:098463de4c5d 215 mbedtls_cipher_free(&ctx);
group-onsemi 0:098463de4c5d 216 return ERR_OK;
group-onsemi 0:098463de4c5d 217
group-onsemi 0:098463de4c5d 218 error:
group-onsemi 0:098463de4c5d 219 mbedtls_cipher_free(&ctx);
group-onsemi 0:098463de4c5d 220 return ERR_OK;
group-onsemi 0:098463de4c5d 221 }
group-onsemi 0:098463de4c5d 222
group-onsemi 0:098463de4c5d 223 #endif /* LWIP_SNMP_V3_CRYPTO */
group-onsemi 0:098463de4c5d 224
group-onsemi 0:098463de4c5d 225 /* A.2.1. Password to Key Sample Code for MD5 */
group-onsemi 0:098463de4c5d 226 void
group-onsemi 0:098463de4c5d 227 snmpv3_password_to_key_md5(
group-onsemi 0:098463de4c5d 228 const u8_t *password, /* IN */
group-onsemi 0:098463de4c5d 229 u8_t passwordlen, /* IN */
group-onsemi 0:098463de4c5d 230 const u8_t *engineID, /* IN - pointer to snmpEngineID */
group-onsemi 0:098463de4c5d 231 u8_t engineLength,/* IN - length of snmpEngineID */
group-onsemi 0:098463de4c5d 232 u8_t *key) /* OUT - pointer to caller 16-octet buffer */
group-onsemi 0:098463de4c5d 233 {
group-onsemi 0:098463de4c5d 234 mbedtls_md5_context MD;
group-onsemi 0:098463de4c5d 235 u8_t *cp, password_buf[64];
group-onsemi 0:098463de4c5d 236 u32_t password_index = 0;
group-onsemi 0:098463de4c5d 237 u8_t i;
group-onsemi 0:098463de4c5d 238 u32_t count = 0;
group-onsemi 0:098463de4c5d 239
group-onsemi 0:098463de4c5d 240 mbedtls_md5_init(&MD); /* initialize MD5 */
group-onsemi 0:098463de4c5d 241 mbedtls_md5_starts(&MD);
group-onsemi 0:098463de4c5d 242
group-onsemi 0:098463de4c5d 243 /**********************************************/
group-onsemi 0:098463de4c5d 244 /* Use while loop until we've done 1 Megabyte */
group-onsemi 0:098463de4c5d 245 /**********************************************/
group-onsemi 0:098463de4c5d 246 while (count < 1048576) {
group-onsemi 0:098463de4c5d 247 cp = password_buf;
group-onsemi 0:098463de4c5d 248 for (i = 0; i < 64; i++) {
group-onsemi 0:098463de4c5d 249 /*************************************************/
group-onsemi 0:098463de4c5d 250 /* Take the next octet of the password, wrapping */
group-onsemi 0:098463de4c5d 251 /* to the beginning of the password as necessary.*/
group-onsemi 0:098463de4c5d 252 /*************************************************/
group-onsemi 0:098463de4c5d 253 *cp++ = password[password_index++ % passwordlen];
group-onsemi 0:098463de4c5d 254 }
group-onsemi 0:098463de4c5d 255 mbedtls_md5_update(&MD, password_buf, 64);
group-onsemi 0:098463de4c5d 256 count += 64;
group-onsemi 0:098463de4c5d 257 }
group-onsemi 0:098463de4c5d 258 mbedtls_md5_finish(&MD, key); /* tell MD5 we're done */
group-onsemi 0:098463de4c5d 259
group-onsemi 0:098463de4c5d 260 /*****************************************************/
group-onsemi 0:098463de4c5d 261 /* Now localize the key with the engineID and pass */
group-onsemi 0:098463de4c5d 262 /* through MD5 to produce final key */
group-onsemi 0:098463de4c5d 263 /* May want to ensure that engineLength <= 32, */
group-onsemi 0:098463de4c5d 264 /* otherwise need to use a buffer larger than 64 */
group-onsemi 0:098463de4c5d 265 /*****************************************************/
group-onsemi 0:098463de4c5d 266 memcpy(password_buf, key, 16);
group-onsemi 0:098463de4c5d 267 memcpy(password_buf + 16, engineID, engineLength);
group-onsemi 0:098463de4c5d 268 memcpy(password_buf + 16 + engineLength, key, 16);
group-onsemi 0:098463de4c5d 269
group-onsemi 0:098463de4c5d 270 mbedtls_md5_starts(&MD);
group-onsemi 0:098463de4c5d 271 mbedtls_md5_update(&MD, password_buf, 32 + engineLength);
group-onsemi 0:098463de4c5d 272 mbedtls_md5_finish(&MD, key);
group-onsemi 0:098463de4c5d 273
group-onsemi 0:098463de4c5d 274 mbedtls_md5_free(&MD);
group-onsemi 0:098463de4c5d 275 return;
group-onsemi 0:098463de4c5d 276 }
group-onsemi 0:098463de4c5d 277
group-onsemi 0:098463de4c5d 278 /* A.2.2. Password to Key Sample Code for SHA */
group-onsemi 0:098463de4c5d 279 void
group-onsemi 0:098463de4c5d 280 snmpv3_password_to_key_sha(
group-onsemi 0:098463de4c5d 281 const u8_t *password, /* IN */
group-onsemi 0:098463de4c5d 282 u8_t passwordlen, /* IN */
group-onsemi 0:098463de4c5d 283 const u8_t *engineID, /* IN - pointer to snmpEngineID */
group-onsemi 0:098463de4c5d 284 u8_t engineLength,/* IN - length of snmpEngineID */
group-onsemi 0:098463de4c5d 285 u8_t *key) /* OUT - pointer to caller 20-octet buffer */
group-onsemi 0:098463de4c5d 286 {
group-onsemi 0:098463de4c5d 287 mbedtls_sha1_context SH;
group-onsemi 0:098463de4c5d 288 u8_t *cp, password_buf[72];
group-onsemi 0:098463de4c5d 289 u32_t password_index = 0;
group-onsemi 0:098463de4c5d 290 u8_t i;
group-onsemi 0:098463de4c5d 291 u32_t count = 0;
group-onsemi 0:098463de4c5d 292
group-onsemi 0:098463de4c5d 293 mbedtls_sha1_init(&SH); /* initialize SHA */
group-onsemi 0:098463de4c5d 294 mbedtls_sha1_starts(&SH);
group-onsemi 0:098463de4c5d 295
group-onsemi 0:098463de4c5d 296 /**********************************************/
group-onsemi 0:098463de4c5d 297 /* Use while loop until we've done 1 Megabyte */
group-onsemi 0:098463de4c5d 298 /**********************************************/
group-onsemi 0:098463de4c5d 299 while (count < 1048576) {
group-onsemi 0:098463de4c5d 300 cp = password_buf;
group-onsemi 0:098463de4c5d 301 for (i = 0; i < 64; i++) {
group-onsemi 0:098463de4c5d 302 /*************************************************/
group-onsemi 0:098463de4c5d 303 /* Take the next octet of the password, wrapping */
group-onsemi 0:098463de4c5d 304 /* to the beginning of the password as necessary.*/
group-onsemi 0:098463de4c5d 305 /*************************************************/
group-onsemi 0:098463de4c5d 306 *cp++ = password[password_index++ % passwordlen];
group-onsemi 0:098463de4c5d 307 }
group-onsemi 0:098463de4c5d 308 mbedtls_sha1_update(&SH, password_buf, 64);
group-onsemi 0:098463de4c5d 309 count += 64;
group-onsemi 0:098463de4c5d 310 }
group-onsemi 0:098463de4c5d 311 mbedtls_sha1_finish(&SH, key); /* tell SHA we're done */
group-onsemi 0:098463de4c5d 312
group-onsemi 0:098463de4c5d 313 /*****************************************************/
group-onsemi 0:098463de4c5d 314 /* Now localize the key with the engineID and pass */
group-onsemi 0:098463de4c5d 315 /* through SHA to produce final key */
group-onsemi 0:098463de4c5d 316 /* May want to ensure that engineLength <= 32, */
group-onsemi 0:098463de4c5d 317 /* otherwise need to use a buffer larger than 72 */
group-onsemi 0:098463de4c5d 318 /*****************************************************/
group-onsemi 0:098463de4c5d 319 memcpy(password_buf, key, 20);
group-onsemi 0:098463de4c5d 320 memcpy(password_buf + 20, engineID, engineLength);
group-onsemi 0:098463de4c5d 321 memcpy(password_buf + 20 + engineLength, key, 20);
group-onsemi 0:098463de4c5d 322
group-onsemi 0:098463de4c5d 323 mbedtls_sha1_starts(&SH);
group-onsemi 0:098463de4c5d 324 mbedtls_sha1_update(&SH, password_buf, 40 + engineLength);
group-onsemi 0:098463de4c5d 325 mbedtls_sha1_finish(&SH, key);
group-onsemi 0:098463de4c5d 326
group-onsemi 0:098463de4c5d 327 mbedtls_sha1_free(&SH);
group-onsemi 0:098463de4c5d 328 return;
group-onsemi 0:098463de4c5d 329 }
group-onsemi 0:098463de4c5d 330
group-onsemi 0:098463de4c5d 331 #endif /* LWIP_SNMP && LWIP_SNMP_V3 && LWIP_SNMP_V3_MBEDTLS */