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/* $OpenBSD: hmac.c,v 1.12 2015/03/24 20:03:44 markus Exp $ */ |
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/* |
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* Copyright (c) 2014 Markus Friedl. All rights reserved. |
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* |
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* Permission to use, copy, modify, and distribute this software for any |
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* purpose with or without fee is hereby granted, provided that the above |
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* copyright notice and this permission notice appear in all copies. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
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*/ |
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#include <sys/types.h> |
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#include <string.h> |
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#include "sshbuf.h" |
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#include "digest.h" |
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#include "hmac.h" |
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struct ssh_hmac_ctx { |
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int alg; |
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struct ssh_digest_ctx *ictx; |
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struct ssh_digest_ctx *octx; |
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struct ssh_digest_ctx *digest; |
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u_char *buf; |
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size_t buf_len; |
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}; |
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size_t |
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ssh_hmac_bytes(int alg) |
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{ |
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return ssh_digest_bytes(alg); |
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} |
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struct ssh_hmac_ctx * |
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ssh_hmac_start(int alg) |
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{ |
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struct ssh_hmac_ctx *ret; |
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if ((ret = calloc(1, sizeof(*ret))) == NULL) |
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return NULL; |
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ret->alg = alg; |
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if ((ret->ictx = ssh_digest_start(alg)) == NULL || |
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(ret->octx = ssh_digest_start(alg)) == NULL || |
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(ret->digest = ssh_digest_start(alg)) == NULL) |
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goto fail; |
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ret->buf_len = ssh_digest_blocksize(ret->ictx); |
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if ((ret->buf = calloc(1, ret->buf_len)) == NULL) |
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goto fail; |
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return ret; |
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fail: |
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ssh_hmac_free(ret); |
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return NULL; |
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} |
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int |
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ssh_hmac_init(struct ssh_hmac_ctx *ctx, const void *key, size_t klen) |
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{ |
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size_t i; |
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/* reset ictx and octx if no is key given */ |
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if (key != NULL) { |
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/* truncate long keys */ |
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if (klen <= ctx->buf_len) |
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memcpy(ctx->buf, key, klen); |
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else if (ssh_digest_memory(ctx->alg, key, klen, ctx->buf, |
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ctx->buf_len) < 0) |
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return -1; |
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for (i = 0; i < ctx->buf_len; i++) |
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ctx->buf[i] ^= 0x36; |
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if (ssh_digest_update(ctx->ictx, ctx->buf, ctx->buf_len) < 0) |
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return -1; |
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for (i = 0; i < ctx->buf_len; i++) |
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ctx->buf[i] ^= 0x36 ^ 0x5c; |
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if (ssh_digest_update(ctx->octx, ctx->buf, ctx->buf_len) < 0) |
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return -1; |
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explicit_bzero(ctx->buf, ctx->buf_len); |
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} |
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/* start with ictx */ |
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if (ssh_digest_copy_state(ctx->ictx, ctx->digest) < 0) |
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return -1; |
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return 0; |
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} |
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int |
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ssh_hmac_update(struct ssh_hmac_ctx *ctx, const void *m, size_t mlen) |
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{ |
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return ssh_digest_update(ctx->digest, m, mlen); |
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} |
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int |
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ssh_hmac_update_buffer(struct ssh_hmac_ctx *ctx, const struct sshbuf *b) |
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{ |
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return ssh_digest_update_buffer(ctx->digest, b); |
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} |
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int |
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ssh_hmac_final(struct ssh_hmac_ctx *ctx, u_char *d, size_t dlen) |
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{ |
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size_t len; |
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len = ssh_digest_bytes(ctx->alg); |
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if (dlen < len || |
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ssh_digest_final(ctx->digest, ctx->buf, len)) |
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return -1; |
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/* switch to octx */ |
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if (ssh_digest_copy_state(ctx->octx, ctx->digest) < 0 || |
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ssh_digest_update(ctx->digest, ctx->buf, len) < 0 || |
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ssh_digest_final(ctx->digest, d, dlen) < 0) |
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return -1; |
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return 0; |
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} |
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void |
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ssh_hmac_free(struct ssh_hmac_ctx *ctx) |
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{ |
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if (ctx != NULL) { |
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ssh_digest_free(ctx->ictx); |
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ssh_digest_free(ctx->octx); |
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ssh_digest_free(ctx->digest); |
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if (ctx->buf) { |
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explicit_bzero(ctx->buf, ctx->buf_len); |
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free(ctx->buf); |
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} |
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explicit_bzero(ctx, sizeof(*ctx)); |
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free(ctx); |
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} |
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} |
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#ifdef TEST |
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/* cc -DTEST hmac.c digest.c buffer.c cleanup.c fatal.c log.c xmalloc.c -lcrypto */ |
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static void |
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hmac_test(void *key, size_t klen, void *m, size_t mlen, u_char *e, size_t elen) |
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{ |
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struct ssh_hmac_ctx *ctx; |
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size_t i; |
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u_char digest[16]; |
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if ((ctx = ssh_hmac_start(SSH_DIGEST_MD5)) == NULL) |
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printf("ssh_hmac_start failed"); |
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if (ssh_hmac_init(ctx, key, klen) < 0 || |
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ssh_hmac_update(ctx, m, mlen) < 0 || |
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ssh_hmac_final(ctx, digest, sizeof(digest)) < 0) |
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printf("ssh_hmac_xxx failed"); |
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ssh_hmac_free(ctx); |
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if (memcmp(e, digest, elen)) { |
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for (i = 0; i < elen; i++) |
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printf("[%zu] %2.2x %2.2x\n", i, e[i], digest[i]); |
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printf("mismatch\n"); |
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} else |
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printf("ok\n"); |
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} |
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int |
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main(int argc, char **argv) |
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{ |
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/* try test vectors from RFC 2104 */ |
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u_char key1[16] = { |
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0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, |
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0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb }; |
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u_char *data1 = "Hi There"; |
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u_char dig1[16] = { |
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0x92, 0x94, 0x72, 0x7a, 0x36, 0x38, 0xbb, 0x1c, |
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0x13, 0xf4, 0x8e, 0xf8, 0x15, 0x8b, 0xfc, 0x9d }; |
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u_char *key2 = "Jefe"; |
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u_char *data2 = "what do ya want for nothing?"; |
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u_char dig2[16] = { |
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0x75, 0x0c, 0x78, 0x3e, 0x6a, 0xb0, 0xb5, 0x03, |
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0xea, 0xa8, 0x6e, 0x31, 0x0a, 0x5d, 0xb7, 0x38 }; |
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u_char key3[16]; |
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u_char data3[50]; |
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u_char dig3[16] = { |
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0x56, 0xbe, 0x34, 0x52, 0x1d, 0x14, 0x4c, 0x88, |
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0xdb, 0xb8, 0xc7, 0x33, 0xf0, 0xe8, 0xb3, 0xf6 }; |
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memset(key3, 0xaa, sizeof(key3)); |
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memset(data3, 0xdd, sizeof(data3)); |
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hmac_test(key1, sizeof(key1), data1, strlen(data1), dig1, sizeof(dig1)); |
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hmac_test(key2, strlen(key2), data2, strlen(data2), dig2, sizeof(dig2)); |
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hmac_test(key3, sizeof(key3), data3, sizeof(data3), dig3, sizeof(dig3)); |
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return 0; |
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} |
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#endif |