| 1 | /*
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| 2 | Unix SMB/CIFS implementation.
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| 3 |
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| 4 | Interface header: HMAC SHA-256 code
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| 5 |
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| 6 | Copyright (C) Andrew Tridgell 2008
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| 7 |
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| 8 | based in hmacsha1.c which is:
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| 9 | Copyright (C) Stefan Metzmacher
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| 10 |
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| 11 | This program is free software; you can redistribute it and/or modify
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| 12 | it under the terms of the GNU General Public License as published by
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| 13 | the Free Software Foundation; either version 3 of the License, or
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| 14 | (at your option) any later version.
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| 15 |
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| 16 | This program is distributed in the hope that it will be useful,
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| 17 | but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 19 | GNU General Public License for more details.
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| 20 |
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| 21 | You should have received a copy of the GNU General Public License
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| 22 | along with this program. If not, see <http://www.gnu.org/licenses/>.
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| 23 | */
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| 24 |
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| 25 | /*
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| 26 | taken direct from rfc2202 implementation and modified for suitable use
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| 27 | */
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| 28 |
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| 29 | #include "includes.h"
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| 30 | #include "../lib/crypto/crypto.h"
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| 31 |
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| 32 | /***********************************************************************
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| 33 | the rfc 2104/2202 version of hmac_sha256 initialisation.
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| 34 | ***********************************************************************/
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| 35 | _PUBLIC_ void hmac_sha256_init(const uint8_t *key, size_t key_len, struct HMACSHA256Context *ctx)
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| 36 | {
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| 37 | int i;
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| 38 | uint8_t tk[SHA256_DIGEST_LENGTH];
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| 39 |
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| 40 | /* if key is longer than 64 bytes reset it to key=HASH(key) */
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| 41 | if (key_len > 64)
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| 42 | {
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| 43 | SHA256_CTX tctx;
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| 44 |
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| 45 | SHA256_Init(&tctx);
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| 46 | SHA256_Update(&tctx, key, key_len);
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| 47 | SHA256_Final(tk, &tctx);
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| 48 |
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| 49 | key = tk;
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| 50 | key_len = SHA256_DIGEST_LENGTH;
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| 51 | }
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| 52 |
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| 53 | /* start out by storing key in pads */
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| 54 | ZERO_STRUCT(ctx->k_ipad);
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| 55 | ZERO_STRUCT(ctx->k_opad);
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| 56 | memcpy( ctx->k_ipad, key, key_len);
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| 57 | memcpy( ctx->k_opad, key, key_len);
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| 58 |
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| 59 | /* XOR key with ipad and opad values */
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| 60 | for (i=0; i<64; i++)
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| 61 | {
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| 62 | ctx->k_ipad[i] ^= 0x36;
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| 63 | ctx->k_opad[i] ^= 0x5c;
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| 64 | }
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| 65 |
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| 66 | SHA256_Init(&ctx->ctx);
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| 67 | SHA256_Update(&ctx->ctx, ctx->k_ipad, 64);
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| 68 | }
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| 69 |
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| 70 | /***********************************************************************
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| 71 | update hmac_sha256 "inner" buffer
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| 72 | ***********************************************************************/
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| 73 | _PUBLIC_ void hmac_sha256_update(const uint8_t *data, size_t data_len, struct HMACSHA256Context *ctx)
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| 74 | {
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| 75 | SHA256_Update(&ctx->ctx, data, data_len); /* then text of datagram */
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| 76 | }
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| 77 |
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| 78 | /***********************************************************************
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| 79 | finish off hmac_sha256 "inner" buffer and generate outer one.
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| 80 | ***********************************************************************/
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| 81 | _PUBLIC_ void hmac_sha256_final(uint8_t digest[SHA256_DIGEST_LENGTH], struct HMACSHA256Context *ctx)
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| 82 | {
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| 83 | SHA256_CTX ctx_o;
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| 84 |
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| 85 | SHA256_Final(digest, &ctx->ctx);
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| 86 |
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| 87 | SHA256_Init(&ctx_o);
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| 88 | SHA256_Update(&ctx_o, ctx->k_opad, 64);
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| 89 | SHA256_Update(&ctx_o, digest, SHA256_DIGEST_LENGTH);
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| 90 | SHA256_Final(digest, &ctx_o);
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| 91 | }
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