digest-openssl.c

   1 /* $OpenBSD: digest-openssl.c,v 1.9 2020/10/29 02:52:43 djm Exp $ */
   2 /*
   3  * Copyright (c) 2013 Damien Miller <djm@mindrot.org>
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  */
  17
  18 #include "includes.h"
  19
  20 #ifdef WITH_OPENSSL
  21
  22 #include <sys/types.h>
  23 #include <limits.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 #include <openssl/evp.h>
  28
  29 #include "openbsd-compat/openssl-compat.h"
  30
  31 #include "sshbuf.h"
  32 #include "digest.h"
  33 #include "ssherr.h"
  34
  35 #ifndef HAVE_EVP_SHA256
  36 # define EVP_sha256 NULL
  37 #endif
  38 #ifndef HAVE_EVP_SHA384
  39 # define EVP_sha384 NULL
  40 #endif
  41 #ifndef HAVE_EVP_SHA512
  42 # define EVP_sha512 NULL
  43 #endif
  44
  45 struct ssh_digest_ctx {
  46         int alg;
  47         EVP_MD_CTX *mdctx;
  48 };
  49
  50 struct ssh_digest {
  51         int id;
  52         const char *name;
  53         size_t digest_len;
  54         const EVP_MD *(*mdfunc)(void);
  55 };
  56
  57 /* NB. Indexed directly by algorithm number */
  58 const struct ssh_digest digests[] = {
  59         { SSH_DIGEST_MD5,       "MD5",          16,     EVP_md5 },
  60         { SSH_DIGEST_SHA1,      "SHA1",         20,     EVP_sha1 },
  61         { SSH_DIGEST_SHA256,    "SHA256",       32,     EVP_sha256 },
  62         { SSH_DIGEST_SHA384,    "SHA384",       48,     EVP_sha384 },
  63         { SSH_DIGEST_SHA512,    "SHA512",       64,     EVP_sha512 },
  64         { -1,                   NULL,           0,      NULL },
  65 };
  66
  67 static const struct ssh_digest *
  68 ssh_digest_by_alg(int alg)
  69 {
  70         if (alg < 0 || alg >= SSH_DIGEST_MAX)
  71                 return NULL;
  72         if (digests[alg].id != alg) /* sanity */
  73                 return NULL;
  74         if (digests[alg].mdfunc == NULL)
  75                 return NULL;
  76         return &(digests[alg]);
  77 }
  78
  79 int
  80 ssh_digest_alg_by_name(const char *name)
  81 {
  82         int alg;
  83
  84         for (alg = 0; digests[alg].id != -1; alg++) {
  85                 if (strcasecmp(name, digests[alg].name) == 0)
  86                         return digests[alg].id;
  87         }
  88         return -1;
  89 }
  90
  91 const char *
  92 ssh_digest_alg_name(int alg)
  93 {
  94         const struct ssh_digest *digest = ssh_digest_by_alg(alg);
  95
  96         return digest == NULL ? NULL : digest->name;
  97 }
  98
  99 size_t
 100 ssh_digest_bytes(int alg)
 101 {
 102         const struct ssh_digest *digest = ssh_digest_by_alg(alg);
 103
 104         return digest == NULL ? 0 : digest->digest_len;
 105 }
 106
 107 size_t
 108 ssh_digest_blocksize(struct ssh_digest_ctx *ctx)
 109 {
 110         return EVP_MD_CTX_block_size(ctx->mdctx);
 111 }
 112
 113 struct ssh_digest_ctx *
 114 ssh_digest_start(int alg)
 115 {
 116         const struct ssh_digest *digest = ssh_digest_by_alg(alg);
 117         struct ssh_digest_ctx *ret;
 118
 119         if (digest == NULL || ((ret = calloc(1, sizeof(*ret))) == NULL))
 120                 return NULL;
 121         ret->alg = alg;
 122         if ((ret->mdctx = EVP_MD_CTX_new()) == NULL) {
 123                 free(ret);
 124                 return NULL;
 125         }
 126         if (EVP_DigestInit_ex(ret->mdctx, digest->mdfunc(), NULL) != 1) {
 127                 ssh_digest_free(ret);
 128                 return NULL;
 129         }
 130         return ret;
 131 }
 132
 133 int
 134 ssh_digest_copy_state(struct ssh_digest_ctx *from, struct ssh_digest_ctx *to)
 135 {
 136         if (from->alg != to->alg)
 137                 return SSH_ERR_INVALID_ARGUMENT;
 138         /* we have bcopy-style order while openssl has memcpy-style */
 139         if (!EVP_MD_CTX_copy_ex(to->mdctx, from->mdctx))
 140                 return SSH_ERR_LIBCRYPTO_ERROR;
 141         return 0;
 142 }
 143
 144 int
 145 ssh_digest_update(struct ssh_digest_ctx *ctx, const void *m, size_t mlen)
 146 {
 147         if (EVP_DigestUpdate(ctx->mdctx, m, mlen) != 1)
 148                 return SSH_ERR_LIBCRYPTO_ERROR;
 149         return 0;
 150 }
 151
 152 int
 153 ssh_digest_update_buffer(struct ssh_digest_ctx *ctx, const struct sshbuf *b)
 154 {
 155         return ssh_digest_update(ctx, sshbuf_ptr(b), sshbuf_len(b));
 156 }
 157
 158 int
 159 ssh_digest_final(struct ssh_digest_ctx *ctx, u_char *d, size_t dlen)
 160 {
 161         const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg);
 162         u_int l = dlen;
 163
 164         if (digest == NULL || dlen > UINT_MAX)
 165                 return SSH_ERR_INVALID_ARGUMENT;
 166         if (dlen < digest->digest_len) /* No truncation allowed */
 167                 return SSH_ERR_INVALID_ARGUMENT;
 168         if (EVP_DigestFinal_ex(ctx->mdctx, d, &l) != 1)
 169                 return SSH_ERR_LIBCRYPTO_ERROR;
 170         if (l != digest->digest_len) /* sanity */
 171                 return SSH_ERR_INTERNAL_ERROR;
 172         return 0;
 173 }
 174
 175 void
 176 ssh_digest_free(struct ssh_digest_ctx *ctx)
 177 {
 178         if (ctx == NULL)
 179                 return;
 180         EVP_MD_CTX_free(ctx->mdctx);
 181         freezero(ctx, sizeof(*ctx));
 182 }
 183
 184 int
 185 ssh_digest_memory(int alg, const void *m, size_t mlen, u_char *d, size_t dlen)
 186 {
 187         const struct ssh_digest *digest = ssh_digest_by_alg(alg);
 188         u_int mdlen;
 189
 190         if (digest == NULL)
 191                 return SSH_ERR_INVALID_ARGUMENT;
 192         if (dlen > UINT_MAX)
 193                 return SSH_ERR_INVALID_ARGUMENT;
 194         if (dlen < digest->digest_len)
 195                 return SSH_ERR_INVALID_ARGUMENT;
 196         mdlen = dlen;
 197         if (!EVP_Digest(m, mlen, d, &mdlen, digest->mdfunc(), NULL))
 198                 return SSH_ERR_LIBCRYPTO_ERROR;
 199         return 0;
 200 }
 201
 202 int
 203 ssh_digest_buffer(int alg, const struct sshbuf *b, u_char *d, size_t dlen)
 204 {
 205         return ssh_digest_memory(alg, sshbuf_ptr(b), sshbuf_len(b), d, dlen);
 206 }
 207 #endif /* WITH_OPENSSL */