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      1 /* $OpenBSD: digest-libc.c,v 1.8 2025/09/05 09:31:31 dtucker Exp $ */
      2 /*
      3  * Copyright (c) 2013 Damien Miller <djm (at) mindrot.org>
      4  * Copyright (c) 2014 Markus Friedl.  All rights reserved.
      5  *
      6  * Permission to use, copy, modify, and distribute this software for any
      7  * purpose with or without fee is hereby granted, provided that the above
      8  * copyright notice and this permission notice appear in all copies.
      9  *
     10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
     11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     17  */
     18 #include "includes.h"
     19 __RCSID("$NetBSD: digest-libc.c,v 1.11 2025/12/28 09:54:06 nia Exp $");
     20 
     21 #include <sys/types.h>
     22 #include <limits.h>
     23 #include <stdlib.h>
     24 #include <string.h>
     25 
     26 #include <md5.h>
     27 #include <sha1.h>
     28 #include <sha2.h>
     29 
     30 #include "ssherr.h"
     31 #include "sshbuf.h"
     32 #include "digest.h"
     33 
     34 typedef void md_init_fn(void *mdctx);
     35 typedef void md_update_fn(void *mdctx, const u_int8_t *m, size_t mlen);
     36 typedef void md_final_fn(u_int8_t[], void *mdctx);
     37 
     38 struct ssh_digest_ctx {
     39 	int alg;
     40 	void *mdctx;
     41 };
     42 
     43 struct ssh_digest {
     44 	int id;
     45 	const char *name;
     46 	size_t block_len;
     47 	size_t digest_len;
     48 	size_t ctx_len;
     49 	md_init_fn *md_init;
     50 	md_update_fn *md_update;
     51 	md_final_fn *md_final;
     52 };
     53 
     54 /* NB. Indexed directly by algorithm number */
     55 const struct ssh_digest digests[SSH_DIGEST_MAX] = {
     56 	{
     57 		SSH_DIGEST_MD5,
     58 		"MD5",
     59 		MD5_BLOCK_LENGTH,
     60 		MD5_DIGEST_LENGTH,
     61 		sizeof(MD5_CTX),
     62 		(md_init_fn *) MD5Init,
     63 		(md_update_fn *) MD5Update,
     64 		(md_final_fn *) MD5Final
     65 	},
     66 	{
     67 		SSH_DIGEST_SHA1,
     68 		"SHA1",
     69 		SHA1_BLOCK_LENGTH,
     70 		SHA1_DIGEST_LENGTH,
     71 		sizeof(SHA1_CTX),
     72 		(md_init_fn *) SHA1Init,
     73 		(md_update_fn *) SHA1Update,
     74 		(md_final_fn *) SHA1Final
     75 	},
     76 	{
     77 		SSH_DIGEST_SHA256,
     78 		"SHA256",
     79 		SHA256_BLOCK_LENGTH,
     80 		SHA256_DIGEST_LENGTH,
     81 		sizeof(SHA256_CTX),
     82 		(md_init_fn *) SHA256Init,
     83 		(md_update_fn *) SHA256Update,
     84 		(md_final_fn *) SHA256Final
     85 	},
     86 	{
     87 		SSH_DIGEST_SHA384,
     88 		"SHA384",
     89 		SHA384_BLOCK_LENGTH,
     90 		SHA384_DIGEST_LENGTH,
     91 		sizeof(SHA384_CTX),
     92 		(md_init_fn *) SHA384Init,
     93 		(md_update_fn *) SHA384Update,
     94 		(md_final_fn *) SHA384Final
     95 	},
     96 	{
     97 		SSH_DIGEST_SHA512,
     98 		"SHA512",
     99 		SHA512_BLOCK_LENGTH,
    100 		SHA512_DIGEST_LENGTH,
    101 		sizeof(SHA512_CTX),
    102 		(md_init_fn *) SHA512Init,
    103 		(md_update_fn *) SHA512Update,
    104 		(md_final_fn *) SHA512Final
    105 	}
    106 };
    107 
    108 static const struct ssh_digest *
    109 ssh_digest_by_alg(int alg)
    110 {
    111 	if (alg < 0 || alg >= SSH_DIGEST_MAX)
    112 		return NULL;
    113 	if (digests[alg].id != alg) /* sanity */
    114 		return NULL;
    115 	return &(digests[alg]);
    116 }
    117 
    118 int
    119 ssh_digest_alg_by_name(const char *name)
    120 {
    121 	int alg;
    122 
    123 	for (alg = 0; alg < SSH_DIGEST_MAX; alg++) {
    124 		if (strcasecmp(name, digests[alg].name) == 0)
    125 			return digests[alg].id;
    126 	}
    127 	return -1;
    128 }
    129 
    130 const char *
    131 ssh_digest_alg_name(int alg)
    132 {
    133 	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
    134 
    135 	return digest == NULL ? NULL : digest->name;
    136 }
    137 
    138 size_t
    139 ssh_digest_bytes(int alg)
    140 {
    141 	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
    142 
    143 	return digest == NULL ? 0 : digest->digest_len;
    144 }
    145 
    146 size_t
    147 ssh_digest_blocksize(struct ssh_digest_ctx *ctx)
    148 {
    149 	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
    150 
    151 	return digest == NULL ? 0 : digest->block_len;
    152 }
    153 
    154 struct ssh_digest_ctx *
    155 ssh_digest_start(int alg)
    156 {
    157 	const struct ssh_digest *digest = ssh_digest_by_alg(alg);
    158 	struct ssh_digest_ctx *ret;
    159 
    160 	if (digest == NULL || (ret = calloc(1, sizeof(*ret))) == NULL)
    161 		return NULL;
    162 	if ((ret->mdctx = calloc(1, digest->ctx_len)) == NULL) {
    163 		free(ret);
    164 		return NULL;
    165 	}
    166 	ret->alg = alg;
    167 	digest->md_init(ret->mdctx);
    168 	return ret;
    169 }
    170 
    171 int
    172 ssh_digest_copy_state(struct ssh_digest_ctx *from, struct ssh_digest_ctx *to)
    173 {
    174 	const struct ssh_digest *digest = ssh_digest_by_alg(from->alg);
    175 
    176 	if (digest == NULL || from->alg != to->alg)
    177 		return SSH_ERR_INVALID_ARGUMENT;
    178 	memcpy(to->mdctx, from->mdctx, digest->ctx_len);
    179 	return 0;
    180 }
    181 
    182 int
    183 ssh_digest_update(struct ssh_digest_ctx *ctx, const void *m, size_t mlen)
    184 {
    185 	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
    186 
    187 	if (digest == NULL)
    188 		return SSH_ERR_INVALID_ARGUMENT;
    189 	digest->md_update(ctx->mdctx, m, mlen);
    190 	return 0;
    191 }
    192 
    193 int
    194 ssh_digest_update_buffer(struct ssh_digest_ctx *ctx, const struct sshbuf *b)
    195 {
    196 	return ssh_digest_update(ctx, sshbuf_ptr(b), sshbuf_len(b));
    197 }
    198 
    199 int
    200 ssh_digest_final(struct ssh_digest_ctx *ctx, u_char *d, size_t dlen)
    201 {
    202 	const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
    203 
    204 	if (digest == NULL)
    205 		return SSH_ERR_INVALID_ARGUMENT;
    206 	if (dlen > UINT_MAX)
    207 		return SSH_ERR_INVALID_ARGUMENT;
    208 	if (dlen < digest->digest_len) /* No truncation allowed */
    209 		return SSH_ERR_INVALID_ARGUMENT;
    210 	digest->md_final(d, ctx->mdctx);
    211 	return 0;
    212 }
    213 
    214 void
    215 ssh_digest_free(struct ssh_digest_ctx *ctx)
    216 {
    217 	const struct ssh_digest *digest;
    218 
    219 	if (ctx != NULL) {
    220 		digest = ssh_digest_by_alg(ctx->alg);
    221 		if (digest) {
    222 			explicit_bzero(ctx->mdctx, digest->ctx_len);
    223 			free(ctx->mdctx);
    224 			freezero(ctx, sizeof(*ctx));
    225 		}
    226 	}
    227 }
    228 
    229 int
    230 ssh_digest_memory(int alg, const void *m, size_t mlen, u_char *d, size_t dlen)
    231 {
    232 	struct ssh_digest_ctx *ctx = ssh_digest_start(alg);
    233 
    234 	if (ctx == NULL)
    235 		return SSH_ERR_INVALID_ARGUMENT;
    236 	if (ssh_digest_update(ctx, m, mlen) != 0 ||
    237 	    ssh_digest_final(ctx, d, dlen) != 0)
    238 		return SSH_ERR_INVALID_ARGUMENT;
    239 	ssh_digest_free(ctx);
    240 	return 0;
    241 }
    242 
    243 int
    244 ssh_digest_buffer(int alg, const struct sshbuf *b, u_char *d, size_t dlen)
    245 {
    246 	return ssh_digest_memory(alg, sshbuf_ptr(b), sshbuf_len(b), d, dlen);
    247 }
    248