1 /* $OpenBSD: ct_vfy.c,v 1.6 2022/01/06 14:34:40 jsing Exp $ */ 2 /* 3 * Written by Rob Stradling (rob@comodo.com) and Stephen Henson 4 * (steve@openssl.org) for the OpenSSL project 2014. 5 */ 6 /* ==================================================================== 7 * Copyright (c) 2014 The OpenSSL Project. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. All advertising materials mentioning features or use of this 22 * software must display the following acknowledgment: 23 * "This product includes software developed by the OpenSSL Project 24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" 25 * 26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 27 * endorse or promote products derived from this software without 28 * prior written permission. For written permission, please contact 29 * licensing@OpenSSL.org. 30 * 31 * 5. Products derived from this software may not be called "OpenSSL" 32 * nor may "OpenSSL" appear in their names without prior written 33 * permission of the OpenSSL Project. 34 * 35 * 6. Redistributions of any form whatsoever must retain the following 36 * acknowledgment: 37 * "This product includes software developed by the OpenSSL Project 38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 51 * OF THE POSSIBILITY OF SUCH DAMAGE. 52 * ==================================================================== 53 * 54 * This product includes cryptographic software written by Eric Young 55 * (eay@cryptsoft.com). This product includes software written by Tim 56 * Hudson (tjh@cryptsoft.com). 57 * 58 */ 59 60 #include <string.h> 61 62 #include <openssl/ct.h> 63 #include <openssl/err.h> 64 #include <openssl/evp.h> 65 #include <openssl/x509.h> 66 67 #include "ct_local.h" 68 69 typedef enum sct_signature_type_t { 70 SIGNATURE_TYPE_NOT_SET = -1, 71 SIGNATURE_TYPE_CERT_TIMESTAMP, 72 SIGNATURE_TYPE_TREE_HASH 73 } SCT_SIGNATURE_TYPE; 74 75 /* 76 * Update encoding for SCT signature verification/generation to supplied 77 * EVP_MD_CTX. 78 */ 79 static int 80 sct_ctx_update(EVP_MD_CTX *ctx, const SCT_CTX *sctx, const SCT *sct) 81 { 82 CBB cbb, entry, extensions; 83 uint8_t *data = NULL; 84 size_t data_len; 85 int ret = 0; 86 87 memset(&cbb, 0, sizeof(cbb)); 88 89 if (sct->entry_type == CT_LOG_ENTRY_TYPE_NOT_SET) 90 goto err; 91 if (sct->entry_type == CT_LOG_ENTRY_TYPE_PRECERT && sctx->ihash == NULL) 92 goto err; 93 94 if (!CBB_init(&cbb, 0)) 95 goto err; 96 97 /* 98 * Build the digitally-signed struct per RFC 6962 section 3.2. 99 */ 100 if (!CBB_add_u8(&cbb, sct->version)) 101 goto err; 102 if (!CBB_add_u8(&cbb, SIGNATURE_TYPE_CERT_TIMESTAMP)) 103 goto err; 104 if (!CBB_add_u64(&cbb, sct->timestamp)) 105 goto err; 106 if (!CBB_add_u16(&cbb, sct->entry_type)) 107 goto err; 108 109 if (sct->entry_type == CT_LOG_ENTRY_TYPE_PRECERT) { 110 if (!CBB_add_bytes(&cbb, sctx->ihash, sctx->ihashlen)) 111 goto err; 112 } 113 114 if (!CBB_add_u24_length_prefixed(&cbb, &entry)) 115 goto err; 116 if (sct->entry_type == CT_LOG_ENTRY_TYPE_PRECERT) { 117 if (sctx->preder == NULL) 118 goto err; 119 if (!CBB_add_bytes(&entry, sctx->preder, sctx->prederlen)) 120 goto err; 121 } else { 122 if (sctx->certder == NULL) 123 goto err; 124 if (!CBB_add_bytes(&entry, sctx->certder, sctx->certderlen)) 125 goto err; 126 } 127 128 if (!CBB_add_u16_length_prefixed(&cbb, &extensions)) 129 goto err; 130 if (sct->ext_len > 0) { 131 if (!CBB_add_bytes(&extensions, sct->ext, sct->ext_len)) 132 goto err; 133 } 134 135 if (!CBB_finish(&cbb, &data, &data_len)) 136 goto err; 137 138 if (!EVP_DigestUpdate(ctx, data, data_len)) 139 goto err; 140 141 ret = 1; 142 143 err: 144 CBB_cleanup(&cbb); 145 free(data); 146 147 return ret; 148 } 149 150 int 151 SCT_CTX_verify(const SCT_CTX *sctx, const SCT *sct) 152 { 153 EVP_MD_CTX *ctx = NULL; 154 int ret = 0; 155 156 if (!SCT_is_complete(sct) || sctx->pkey == NULL || 157 sct->entry_type == CT_LOG_ENTRY_TYPE_NOT_SET || 158 (sct->entry_type == CT_LOG_ENTRY_TYPE_PRECERT && 159 sctx->ihash == NULL)) { 160 CTerror(CT_R_SCT_NOT_SET); 161 return 0; 162 } 163 if (sct->version != SCT_VERSION_V1) { 164 CTerror(CT_R_SCT_UNSUPPORTED_VERSION); 165 return 0; 166 } 167 if (sct->log_id_len != sctx->pkeyhashlen || 168 memcmp(sct->log_id, sctx->pkeyhash, sctx->pkeyhashlen) != 0) { 169 CTerror(CT_R_SCT_LOG_ID_MISMATCH); 170 return 0; 171 } 172 if (sct->timestamp > sctx->epoch_time_in_ms) { 173 CTerror(CT_R_SCT_FUTURE_TIMESTAMP); 174 return 0; 175 } 176 177 if ((ctx = EVP_MD_CTX_new()) == NULL) 178 goto end; 179 180 if (!EVP_DigestVerifyInit(ctx, NULL, EVP_sha256(), NULL, sctx->pkey)) 181 goto end; 182 183 if (!sct_ctx_update(ctx, sctx, sct)) 184 goto end; 185 186 /* Verify signature */ 187 /* If ret < 0 some other error: fall through without setting error */ 188 if ((ret = EVP_DigestVerifyFinal(ctx, sct->sig, sct->sig_len)) == 0) 189 CTerror(CT_R_SCT_INVALID_SIGNATURE); 190 191 end: 192 EVP_MD_CTX_free(ctx); 193 194 return ret; 195 } 196