1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2005-2011 Pawel Jakub Dawidek <pawel@dawidek.net> 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include <sys/param.h> 33 #ifdef _KERNEL 34 #include <sys/malloc.h> 35 #include <sys/systm.h> 36 #include <geom/geom.h> 37 #else 38 #include <stdio.h> 39 #include <stdint.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <strings.h> 43 #include <errno.h> 44 #endif 45 46 #include <geom/eli/g_eli.h> 47 48 #ifdef _KERNEL 49 MALLOC_DECLARE(M_ELI); 50 #endif 51 52 /* 53 * Verify if the given 'key' is correct. 54 * Return 1 if it is correct and 0 otherwise. 55 */ 56 static int 57 g_eli_mkey_verify(const unsigned char *mkey, const unsigned char *key) 58 { 59 const unsigned char *odhmac; /* On-disk HMAC. */ 60 unsigned char chmac[SHA512_MDLEN]; /* Calculated HMAC. */ 61 unsigned char hmkey[SHA512_MDLEN]; /* Key for HMAC. */ 62 63 /* 64 * The key for HMAC calculations is: hmkey = HMAC_SHA512(Derived-Key, 0) 65 */ 66 g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x00", 1, hmkey, 0); 67 68 odhmac = mkey + G_ELI_DATAIVKEYLEN; 69 70 /* Calculate HMAC from Data-Key and IV-Key. */ 71 g_eli_crypto_hmac(hmkey, sizeof(hmkey), mkey, G_ELI_DATAIVKEYLEN, 72 chmac, 0); 73 74 explicit_bzero(hmkey, sizeof(hmkey)); 75 76 /* 77 * Compare calculated HMAC with HMAC from metadata. 78 * If two HMACs are equal, 'key' is correct. 79 */ 80 return (!bcmp(odhmac, chmac, SHA512_MDLEN)); 81 } 82 83 /* 84 * Calculate HMAC from Data-Key and IV-Key. 85 */ 86 void 87 g_eli_mkey_hmac(unsigned char *mkey, const unsigned char *key) 88 { 89 unsigned char hmkey[SHA512_MDLEN]; /* Key for HMAC. */ 90 unsigned char *odhmac; /* On-disk HMAC. */ 91 92 /* 93 * The key for HMAC calculations is: hmkey = HMAC_SHA512(Derived-Key, 0) 94 */ 95 g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x00", 1, hmkey, 0); 96 97 odhmac = mkey + G_ELI_DATAIVKEYLEN; 98 /* Calculate HMAC from Data-Key and IV-Key. */ 99 g_eli_crypto_hmac(hmkey, sizeof(hmkey), mkey, G_ELI_DATAIVKEYLEN, 100 odhmac, 0); 101 102 explicit_bzero(hmkey, sizeof(hmkey)); 103 } 104 105 /* 106 * Find and decrypt Master Key encrypted with 'key' at slot 'nkey'. 107 * Return 0 on success, > 0 on failure, -1 on bad key. 108 */ 109 int 110 g_eli_mkey_decrypt(const struct g_eli_metadata *md, const unsigned char *key, 111 unsigned char *mkey, unsigned nkey) 112 { 113 unsigned char tmpmkey[G_ELI_MKEYLEN]; 114 unsigned char enckey[SHA512_MDLEN]; /* Key for encryption. */ 115 const unsigned char *mmkey; 116 int bit, error; 117 118 if (nkey > G_ELI_MKEYLEN) 119 return (-1); 120 121 /* 122 * The key for encryption is: enckey = HMAC_SHA512(Derived-Key, 1) 123 */ 124 g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x01", 1, enckey, 0); 125 126 mmkey = md->md_mkeys + G_ELI_MKEYLEN * nkey; 127 bit = (1 << nkey); 128 if (!(md->md_keys & bit)) 129 return (-1); 130 bcopy(mmkey, tmpmkey, G_ELI_MKEYLEN); 131 error = g_eli_crypto_decrypt(md->md_ealgo, tmpmkey, 132 G_ELI_MKEYLEN, enckey, md->md_keylen); 133 if (error != 0) { 134 explicit_bzero(tmpmkey, sizeof(tmpmkey)); 135 explicit_bzero(enckey, sizeof(enckey)); 136 return (error); 137 } 138 if (g_eli_mkey_verify(tmpmkey, key)) { 139 bcopy(tmpmkey, mkey, G_ELI_DATAIVKEYLEN); 140 explicit_bzero(tmpmkey, sizeof(tmpmkey)); 141 explicit_bzero(enckey, sizeof(enckey)); 142 return (0); 143 } 144 explicit_bzero(enckey, sizeof(enckey)); 145 explicit_bzero(tmpmkey, sizeof(tmpmkey)); 146 147 return (-1); 148 } 149 150 /* 151 * Find and decrypt Master Key encrypted with 'key'. 152 * Return decrypted Master Key number in 'nkeyp' if not NULL. 153 * Return 0 on success, > 0 on failure, -1 on bad key. 154 */ 155 int 156 g_eli_mkey_decrypt_any(const struct g_eli_metadata *md, 157 const unsigned char *key, unsigned char *mkey, unsigned *nkeyp) 158 { 159 int error, nkey; 160 161 if (nkeyp != NULL) 162 *nkeyp = -1; 163 164 error = -1; 165 for (nkey = 0; nkey < G_ELI_MAXMKEYS; nkey++) { 166 error = g_eli_mkey_decrypt(md, key, mkey, nkey); 167 if (error == 0) { 168 if (nkeyp != NULL) 169 *nkeyp = nkey; 170 break; 171 } else if (error > 0) { 172 break; 173 } 174 } 175 176 return (error); 177 } 178 179 /* 180 * Encrypt the Master-Key and calculate HMAC to be able to verify it in the 181 * future. 182 */ 183 int 184 g_eli_mkey_encrypt(unsigned algo, const unsigned char *key, unsigned keylen, 185 unsigned char *mkey) 186 { 187 unsigned char enckey[SHA512_MDLEN]; /* Key for encryption. */ 188 int error; 189 190 /* 191 * To calculate HMAC, the whole key (G_ELI_USERKEYLEN bytes long) will 192 * be used. 193 */ 194 g_eli_mkey_hmac(mkey, key); 195 /* 196 * The key for encryption is: enckey = HMAC_SHA512(Derived-Key, 1) 197 */ 198 g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x01", 1, enckey, 0); 199 /* 200 * Encrypt the Master-Key and HMAC() result with the given key (this 201 * time only 'keylen' bits from the key are used). 202 */ 203 error = g_eli_crypto_encrypt(algo, mkey, G_ELI_MKEYLEN, enckey, keylen); 204 205 explicit_bzero(enckey, sizeof(enckey)); 206 207 return (error); 208 } 209 210 #ifdef _KERNEL 211 /* 212 * When doing encryption only, copy IV key and encryption key. 213 * When doing encryption and authentication, copy IV key, generate encryption 214 * key and generate authentication key. 215 */ 216 void 217 g_eli_mkey_propagate(struct g_eli_softc *sc, const unsigned char *mkey) 218 { 219 220 /* Remember the Master Key. */ 221 bcopy(mkey, sc->sc_mkey, sizeof(sc->sc_mkey)); 222 223 bcopy(mkey, sc->sc_ivkey, sizeof(sc->sc_ivkey)); 224 mkey += sizeof(sc->sc_ivkey); 225 226 /* 227 * The authentication key is: akey = HMAC_SHA512(Data-Key, 0x11) 228 */ 229 if ((sc->sc_flags & G_ELI_FLAG_AUTH) != 0) { 230 g_eli_crypto_hmac(mkey, G_ELI_MAXKEYLEN, "\x11", 1, 231 sc->sc_akey, 0); 232 } else { 233 arc4rand(sc->sc_akey, sizeof(sc->sc_akey), 0); 234 } 235 236 /* Initialize encryption keys. */ 237 g_eli_key_init(sc); 238 239 if ((sc->sc_flags & G_ELI_FLAG_AUTH) != 0) { 240 /* 241 * Precalculate SHA256 for HMAC key generation. 242 * This is expensive operation and we can do it only once now or 243 * for every access to sector, so now will be much better. 244 */ 245 SHA256_Init(&sc->sc_akeyctx); 246 SHA256_Update(&sc->sc_akeyctx, sc->sc_akey, 247 sizeof(sc->sc_akey)); 248 } 249 /* 250 * Precalculate SHA256 for IV generation. 251 * This is expensive operation and we can do it only once now or for 252 * every access to sector, so now will be much better. 253 */ 254 switch (sc->sc_ealgo) { 255 case CRYPTO_AES_XTS: 256 break; 257 default: 258 SHA256_Init(&sc->sc_ivctx); 259 SHA256_Update(&sc->sc_ivctx, sc->sc_ivkey, 260 sizeof(sc->sc_ivkey)); 261 break; 262 } 263 } 264 #endif 265