g_eli_key.c revision 202976
1/*- 2 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <sys/cdefs.h> 28__FBSDID("$FreeBSD: head/sys/geom/eli/g_eli_key.c 202976 2010-01-25 16:58:58Z trasz $"); 29 30#include <sys/param.h> 31#ifdef _KERNEL 32#include <sys/malloc.h> 33#include <sys/systm.h> 34#include <geom/geom.h> 35#else 36#include <stdio.h> 37#include <stdint.h> 38#include <stdlib.h> 39#include <string.h> 40#include <strings.h> 41#include <errno.h> 42#endif 43 44#include <geom/eli/g_eli.h> 45 46 47/* 48 * Verify if the given 'key' is correct. 49 * Return 1 if it is correct and 0 otherwise. 50 */ 51static int 52g_eli_mkey_verify(const unsigned char *mkey, const unsigned char *key) 53{ 54 const unsigned char *odhmac; /* On-disk HMAC. */ 55 unsigned char chmac[SHA512_MDLEN]; /* Calculated HMAC. */ 56 unsigned char hmkey[SHA512_MDLEN]; /* Key for HMAC. */ 57 58 /* 59 * The key for HMAC calculations is: hmkey = HMAC_SHA512(Derived-Key, 0) 60 */ 61 g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x00", 1, hmkey, 0); 62 63 odhmac = mkey + G_ELI_DATAIVKEYLEN; 64 65 /* Calculate HMAC from Data-Key and IV-Key. */ 66 g_eli_crypto_hmac(hmkey, sizeof(hmkey), mkey, G_ELI_DATAIVKEYLEN, 67 chmac, 0); 68 69 bzero(hmkey, sizeof(hmkey)); 70 71 /* 72 * Compare calculated HMAC with HMAC from metadata. 73 * If two HMACs are equal, 'key' is correct. 74 */ 75 return (!bcmp(odhmac, chmac, SHA512_MDLEN)); 76} 77 78/* 79 * Calculate HMAC from Data-Key and IV-Key. 80 */ 81void 82g_eli_mkey_hmac(unsigned char *mkey, const unsigned char *key) 83{ 84 unsigned char hmkey[SHA512_MDLEN]; /* Key for HMAC. */ 85 unsigned char *odhmac; /* On-disk HMAC. */ 86 87 /* 88 * The key for HMAC calculations is: hmkey = HMAC_SHA512(Derived-Key, 0) 89 */ 90 g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x00", 1, hmkey, 0); 91 92 odhmac = mkey + G_ELI_DATAIVKEYLEN; 93 /* Calculate HMAC from Data-Key and IV-Key. */ 94 g_eli_crypto_hmac(hmkey, sizeof(hmkey), mkey, G_ELI_DATAIVKEYLEN, 95 odhmac, 0); 96 97 bzero(hmkey, sizeof(hmkey)); 98} 99 100/* 101 * Find and decrypt Master Key encrypted with 'key'. 102 * Return decrypted Master Key number in 'nkeyp' if not NULL. 103 * Return 0 on success, > 0 on failure, -1 on bad key. 104 */ 105int 106g_eli_mkey_decrypt(const struct g_eli_metadata *md, const unsigned char *key, 107 unsigned char *mkey, unsigned *nkeyp) 108{ 109 unsigned char tmpmkey[G_ELI_MKEYLEN]; 110 unsigned char enckey[SHA512_MDLEN]; /* Key for encryption. */ 111 const unsigned char *mmkey; 112 int bit, error, nkey; 113 114 if (nkeyp != NULL) 115 *nkeyp = -1; 116 117 /* 118 * The key for encryption is: enckey = HMAC_SHA512(Derived-Key, 1) 119 */ 120 g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x01", 1, enckey, 0); 121 122 mmkey = md->md_mkeys; 123 for (nkey = 0; nkey < G_ELI_MAXMKEYS; nkey++, mmkey += G_ELI_MKEYLEN) { 124 bit = (1 << nkey); 125 if (!(md->md_keys & bit)) 126 continue; 127 bcopy(mmkey, tmpmkey, G_ELI_MKEYLEN); 128 error = g_eli_crypto_decrypt(md->md_ealgo, tmpmkey, 129 G_ELI_MKEYLEN, enckey, md->md_keylen); 130 if (error != 0) { 131 bzero(tmpmkey, sizeof(tmpmkey)); 132 bzero(enckey, sizeof(enckey)); 133 return (error); 134 } 135 if (g_eli_mkey_verify(tmpmkey, key)) { 136 bcopy(tmpmkey, mkey, G_ELI_DATAIVKEYLEN); 137 bzero(tmpmkey, sizeof(tmpmkey)); 138 bzero(enckey, sizeof(enckey)); 139 if (nkeyp != NULL) 140 *nkeyp = nkey; 141 return (0); 142 } 143 } 144 bzero(enckey, sizeof(enckey)); 145 bzero(tmpmkey, sizeof(tmpmkey)); 146 return (-1); 147} 148 149/* 150 * Encrypt the Master-Key and calculate HMAC to be able to verify it in the 151 * future. 152 */ 153int 154g_eli_mkey_encrypt(unsigned algo, const unsigned char *key, unsigned keylen, 155 unsigned char *mkey) 156{ 157 unsigned char enckey[SHA512_MDLEN]; /* Key for encryption. */ 158 int error; 159 160 /* 161 * To calculate HMAC, the whole key (G_ELI_USERKEYLEN bytes long) will 162 * be used. 163 */ 164 g_eli_mkey_hmac(mkey, key); 165 /* 166 * The key for encryption is: enckey = HMAC_SHA512(Derived-Key, 1) 167 */ 168 g_eli_crypto_hmac(key, G_ELI_USERKEYLEN, "\x01", 1, enckey, 0); 169 /* 170 * Encrypt the Master-Key and HMAC() result with the given key (this 171 * time only 'keylen' bits from the key are used). 172 */ 173 error = g_eli_crypto_encrypt(algo, mkey, G_ELI_MKEYLEN, enckey, keylen); 174 175 bzero(enckey, sizeof(enckey)); 176 177 return (error); 178} 179 180#ifdef _KERNEL 181/* 182 * When doing encryption only, copy IV key and encryption key. 183 * When doing encryption and authentication, copy IV key, generate encryption 184 * key and generate authentication key. 185 */ 186void 187g_eli_mkey_propagate(struct g_eli_softc *sc, const unsigned char *mkey) 188{ 189 190 /* Remember the Master Key. */ 191 bcopy(mkey, sc->sc_mkey, sizeof(sc->sc_mkey)); 192 193 bcopy(mkey, sc->sc_ivkey, sizeof(sc->sc_ivkey)); 194 mkey += sizeof(sc->sc_ivkey); 195 196 if (!(sc->sc_flags & G_ELI_FLAG_AUTH)) { 197 bcopy(mkey, sc->sc_ekey, sizeof(sc->sc_ekey)); 198 } else { 199 /* 200 * The encryption key is: ekey = HMAC_SHA512(Master-Key, 0x10) 201 * The authentication key is: akey = HMAC_SHA512(Master-Key, 0x11) 202 */ 203 g_eli_crypto_hmac(mkey, G_ELI_MAXKEYLEN, "\x10", 1, sc->sc_ekey, 0); 204 g_eli_crypto_hmac(mkey, G_ELI_MAXKEYLEN, "\x11", 1, sc->sc_akey, 0); 205 } 206 207} 208#endif 209