1 /* $OpenBSD: digest-openssl.c,v 1.7 2017/05/08 22:57:38 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 <sys/types.h> 19 #include <limits.h> 20 #include <stdlib.h> 21 #include <string.h> 22 23 #include <openssl/evp.h> 24 25 #include "sshbuf.h" 26 #include "digest.h" 27 #include "ssherr.h" 28 29 struct ssh_digest_ctx { 30 int alg; 31 EVP_MD_CTX mdctx; 32 }; 33 34 struct ssh_digest { 35 int id; 36 const char *name; 37 size_t digest_len; 38 const EVP_MD *(*mdfunc)(void); 39 }; 40 41 /* NB. Indexed directly by algorithm number */ 42 const struct ssh_digest digests[] = { 43 { SSH_DIGEST_MD5, "MD5", 16, EVP_md5 }, 44 { SSH_DIGEST_SHA1, "SHA1", 20, EVP_sha1 }, 45 { SSH_DIGEST_SHA256, "SHA256", 32, EVP_sha256 }, 46 { SSH_DIGEST_SHA384, "SHA384", 48, EVP_sha384 }, 47 { SSH_DIGEST_SHA512, "SHA512", 64, EVP_sha512 }, 48 { -1, NULL, 0, NULL }, 49 }; 50 51 static const struct ssh_digest * 52 ssh_digest_by_alg(int alg) 53 { 54 if (alg < 0 || alg >= SSH_DIGEST_MAX) 55 return NULL; 56 if (digests[alg].id != alg) /* sanity */ 57 return NULL; 58 return &(digests[alg]); 59 } 60 61 int 62 ssh_digest_alg_by_name(const char *name) 63 { 64 int alg; 65 66 for (alg = 0; digests[alg].id != -1; alg++) { 67 if (strcasecmp(name, digests[alg].name) == 0) 68 return digests[alg].id; 69 } 70 return -1; 71 } 72 73 const char * 74 ssh_digest_alg_name(int alg) 75 { 76 const struct ssh_digest *digest = ssh_digest_by_alg(alg); 77 78 return digest == NULL ? NULL : digest->name; 79 } 80 81 size_t 82 ssh_digest_bytes(int alg) 83 { 84 const struct ssh_digest *digest = ssh_digest_by_alg(alg); 85 86 return digest == NULL ? 0 : digest->digest_len; 87 } 88 89 size_t 90 ssh_digest_blocksize(struct ssh_digest_ctx *ctx) 91 { 92 return EVP_MD_CTX_block_size(&ctx->mdctx); 93 } 94 95 struct ssh_digest_ctx * 96 ssh_digest_start(int alg) 97 { 98 const struct ssh_digest *digest = ssh_digest_by_alg(alg); 99 struct ssh_digest_ctx *ret; 100 101 if (digest == NULL || ((ret = calloc(1, sizeof(*ret))) == NULL)) 102 return NULL; 103 ret->alg = alg; 104 EVP_MD_CTX_init(&ret->mdctx); 105 if (EVP_DigestInit_ex(&ret->mdctx, digest->mdfunc(), NULL) != 1) { 106 free(ret); 107 return NULL; 108 } 109 return ret; 110 } 111 112 int 113 ssh_digest_copy_state(struct ssh_digest_ctx *from, struct ssh_digest_ctx *to) 114 { 115 if (from->alg != to->alg) 116 return SSH_ERR_INVALID_ARGUMENT; 117 /* we have bcopy-style order while openssl has memcpy-style */ 118 if (!EVP_MD_CTX_copy_ex(&to->mdctx, &from->mdctx)) 119 return SSH_ERR_LIBCRYPTO_ERROR; 120 return 0; 121 } 122 123 int 124 ssh_digest_update(struct ssh_digest_ctx *ctx, const void *m, size_t mlen) 125 { 126 if (EVP_DigestUpdate(&ctx->mdctx, m, mlen) != 1) 127 return SSH_ERR_LIBCRYPTO_ERROR; 128 return 0; 129 } 130 131 int 132 ssh_digest_update_buffer(struct ssh_digest_ctx *ctx, const struct sshbuf *b) 133 { 134 return ssh_digest_update(ctx, sshbuf_ptr(b), sshbuf_len(b)); 135 } 136 137 int 138 ssh_digest_final(struct ssh_digest_ctx *ctx, u_char *d, size_t dlen) 139 { 140 const struct ssh_digest *digest = ssh_digest_by_alg(ctx->alg); 141 u_int l = dlen; 142 143 if (digest == NULL || dlen > UINT_MAX) 144 return SSH_ERR_INVALID_ARGUMENT; 145 if (dlen < digest->digest_len) /* No truncation allowed */ 146 return SSH_ERR_INVALID_ARGUMENT; 147 if (EVP_DigestFinal_ex(&ctx->mdctx, d, &l) != 1) 148 return SSH_ERR_LIBCRYPTO_ERROR; 149 if (l != digest->digest_len) /* sanity */ 150 return SSH_ERR_INTERNAL_ERROR; 151 return 0; 152 } 153 154 void 155 ssh_digest_free(struct ssh_digest_ctx *ctx) 156 { 157 if (ctx != NULL) { 158 EVP_MD_CTX_cleanup(&ctx->mdctx); 159 explicit_bzero(ctx, sizeof(*ctx)); 160 free(ctx); 161 } 162 } 163 164 int 165 ssh_digest_memory(int alg, const void *m, size_t mlen, u_char *d, size_t dlen) 166 { 167 const struct ssh_digest *digest = ssh_digest_by_alg(alg); 168 u_int mdlen; 169 170 if (digest == NULL) 171 return SSH_ERR_INVALID_ARGUMENT; 172 if (dlen > UINT_MAX) 173 return SSH_ERR_INVALID_ARGUMENT; 174 if (dlen < digest->digest_len) 175 return SSH_ERR_INVALID_ARGUMENT; 176 mdlen = dlen; 177 if (!EVP_Digest(m, mlen, d, &mdlen, digest->mdfunc(), NULL)) 178 return SSH_ERR_LIBCRYPTO_ERROR; 179 return 0; 180 } 181 182 int 183 ssh_digest_buffer(int alg, const struct sshbuf *b, u_char *d, size_t dlen) 184 { 185 return ssh_digest_memory(alg, sshbuf_ptr(b), sshbuf_len(b), d, dlen); 186 } 187