/* $OpenBSD: hmac.c,v 1.14 2020/02/26 13:40:09 jsg Exp $ */ /* * Copyright (c) 2014 Markus Friedl. All rights reserved. * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include "includes.h" __RCSID("$NetBSD: hmac.c,v 1.6.20.1 2023/12/25 12:31:04 martin Exp $"); #include #include #include #include "sshbuf.h" #include "digest.h" #include "hmac.h" struct ssh_hmac_ctx { int alg; struct ssh_digest_ctx *ictx; struct ssh_digest_ctx *octx; struct ssh_digest_ctx *digest; u_char *buf; size_t buf_len; }; size_t ssh_hmac_bytes(int alg) { return ssh_digest_bytes(alg); } struct ssh_hmac_ctx * ssh_hmac_start(int alg) { struct ssh_hmac_ctx *ret; if ((ret = calloc(1, sizeof(*ret))) == NULL) return NULL; ret->alg = alg; if ((ret->ictx = ssh_digest_start(alg)) == NULL || (ret->octx = ssh_digest_start(alg)) == NULL || (ret->digest = ssh_digest_start(alg)) == NULL) goto fail; ret->buf_len = ssh_digest_blocksize(ret->ictx); if ((ret->buf = calloc(1, ret->buf_len)) == NULL) goto fail; return ret; fail: ssh_hmac_free(ret); return NULL; } int ssh_hmac_init(struct ssh_hmac_ctx *ctx, const void *key, size_t klen) { size_t i; /* reset ictx and octx if no is key given */ if (key != NULL) { /* truncate long keys */ if (klen <= ctx->buf_len) memcpy(ctx->buf, key, klen); else if (ssh_digest_memory(ctx->alg, key, klen, ctx->buf, ctx->buf_len) < 0) return -1; for (i = 0; i < ctx->buf_len; i++) ctx->buf[i] ^= 0x36; if (ssh_digest_update(ctx->ictx, ctx->buf, ctx->buf_len) < 0) return -1; for (i = 0; i < ctx->buf_len; i++) ctx->buf[i] ^= 0x36 ^ 0x5c; if (ssh_digest_update(ctx->octx, ctx->buf, ctx->buf_len) < 0) return -1; explicit_bzero(ctx->buf, ctx->buf_len); } /* start with ictx */ if (ssh_digest_copy_state(ctx->ictx, ctx->digest) < 0) return -1; return 0; } int ssh_hmac_update(struct ssh_hmac_ctx *ctx, const void *m, size_t mlen) { return ssh_digest_update(ctx->digest, m, mlen); } int ssh_hmac_update_buffer(struct ssh_hmac_ctx *ctx, const struct sshbuf *b) { return ssh_digest_update_buffer(ctx->digest, b); } int ssh_hmac_final(struct ssh_hmac_ctx *ctx, u_char *d, size_t dlen) { size_t len; len = ssh_digest_bytes(ctx->alg); if (dlen < len || ssh_digest_final(ctx->digest, ctx->buf, len)) return -1; /* switch to octx */ if (ssh_digest_copy_state(ctx->octx, ctx->digest) < 0 || ssh_digest_update(ctx->digest, ctx->buf, len) < 0 || ssh_digest_final(ctx->digest, d, dlen) < 0) return -1; return 0; } void ssh_hmac_free(struct ssh_hmac_ctx *ctx) { if (ctx != NULL) { ssh_digest_free(ctx->ictx); ssh_digest_free(ctx->octx); ssh_digest_free(ctx->digest); if (ctx->buf) { explicit_bzero(ctx->buf, ctx->buf_len); free(ctx->buf); } freezero(ctx, sizeof(*ctx)); } } #ifdef TEST /* cc -DTEST hmac.c digest.c buffer.c cleanup.c fatal.c log.c xmalloc.c -lcrypto */ static void hmac_test(void *key, size_t klen, void *m, size_t mlen, u_char *e, size_t elen) { struct ssh_hmac_ctx *ctx; size_t i; u_char digest[16]; if ((ctx = ssh_hmac_start(SSH_DIGEST_MD5)) == NULL) printf("ssh_hmac_start failed"); if (ssh_hmac_init(ctx, key, klen) < 0 || ssh_hmac_update(ctx, m, mlen) < 0 || ssh_hmac_final(ctx, digest, sizeof(digest)) < 0) printf("ssh_hmac_xxx failed"); ssh_hmac_free(ctx); if (memcmp(e, digest, elen)) { for (i = 0; i < elen; i++) printf("[%zu] %2.2x %2.2x\n", i, e[i], digest[i]); printf("mismatch\n"); } else printf("ok\n"); } int main(int argc, char **argv) { /* try test vectors from RFC 2104 */ u_char key1[16] = { 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb, 0xb }; u_char *data1 = "Hi There"; u_char dig1[16] = { 0x92, 0x94, 0x72, 0x7a, 0x36, 0x38, 0xbb, 0x1c, 0x13, 0xf4, 0x8e, 0xf8, 0x15, 0x8b, 0xfc, 0x9d }; u_char *key2 = "Jefe"; u_char *data2 = "what do ya want for nothing?"; u_char dig2[16] = { 0x75, 0x0c, 0x78, 0x3e, 0x6a, 0xb0, 0xb5, 0x03, 0xea, 0xa8, 0x6e, 0x31, 0x0a, 0x5d, 0xb7, 0x38 }; u_char key3[16]; u_char data3[50]; u_char dig3[16] = { 0x56, 0xbe, 0x34, 0x52, 0x1d, 0x14, 0x4c, 0x88, 0xdb, 0xb8, 0xc7, 0x33, 0xf0, 0xe8, 0xb3, 0xf6 }; memset(key3, 0xaa, sizeof(key3)); memset(data3, 0xdd, sizeof(data3)); hmac_test(key1, sizeof(key1), data1, strlen(data1), dig1, sizeof(dig1)); hmac_test(key2, strlen(key2), data2, strlen(data2), dig2, sizeof(dig2)); hmac_test(key3, sizeof(key3), data3, sizeof(data3), dig3, sizeof(dig3)); return 0; } #endif