1 /* $OpenBSD: softraid.c,v 1.3 2017/11/10 16:50:59 sunil Exp $ */ 2 3 /* 4 * Copyright (c) 2012 Joel Sing <jsing@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/param.h> 20 #include <sys/queue.h> 21 22 #include <dev/biovar.h> 23 #include <dev/softraidvar.h> 24 25 #include <lib/libsa/bcrypt_pbkdf.h> 26 #include <lib/libsa/hmac_sha1.h> 27 #include <lib/libsa/pkcs5_pbkdf2.h> 28 #include <lib/libsa/rijndael.h> 29 30 #include "stand.h" 31 #include "softraid.h" 32 33 #define RIJNDAEL128_BLOCK_LEN 16 34 #define PASSPHRASE_LENGTH 1024 35 36 #define SR_CRYPTO_KEYBLOCK_BYTES SR_CRYPTO_MAXKEYS * SR_CRYPTO_KEYBYTES 37 38 /* List of softraid volumes. */ 39 struct sr_boot_volume_head sr_volumes; 40 41 /* List of softraid keydisks. */ 42 struct sr_boot_keydisk_head sr_keydisks; 43 44 #ifdef DEBUG 45 void 46 printhex(const char *s, const u_int8_t *buf, size_t len) 47 { 48 u_int8_t n1, n2; 49 size_t i; 50 51 printf("%s: ", s); 52 for (i = 0; i < len; i++) { 53 n1 = buf[i] & 0x0f; 54 n2 = buf[i] >> 4; 55 printf("%c", n2 > 9 ? n2 + 'a' - 10 : n2 + '0'); 56 printf("%c", n1 > 9 ? n1 + 'a' - 10 : n1 + '0'); 57 } 58 printf("\n"); 59 } 60 #endif 61 62 void 63 sr_clear_keys(void) 64 { 65 struct sr_boot_volume *bv; 66 struct sr_boot_keydisk *kd; 67 68 SLIST_FOREACH(bv, &sr_volumes, sbv_link) { 69 if (bv->sbv_level != 'C') 70 continue; 71 if (bv->sbv_keys != NULL) { 72 explicit_bzero(bv->sbv_keys, SR_CRYPTO_KEYBLOCK_BYTES); 73 free(bv->sbv_keys, SR_CRYPTO_KEYBLOCK_BYTES); 74 bv->sbv_keys = NULL; 75 } 76 if (bv->sbv_maskkey != NULL) { 77 explicit_bzero(bv->sbv_maskkey, SR_CRYPTO_MAXKEYBYTES); 78 free(bv->sbv_maskkey, SR_CRYPTO_MAXKEYBYTES); 79 bv->sbv_maskkey = NULL; 80 } 81 } 82 SLIST_FOREACH(kd, &sr_keydisks, kd_link) { 83 explicit_bzero(kd, sizeof(*kd)); 84 free(kd, sizeof(*kd)); 85 } 86 } 87 88 void 89 sr_crypto_calculate_check_hmac_sha1(u_int8_t *maskkey, int maskkey_size, 90 u_int8_t *key, int key_size, u_char *check_digest) 91 { 92 u_int8_t check_key[SHA1_DIGEST_LENGTH]; 93 SHA1_CTX shactx; 94 95 explicit_bzero(check_key, sizeof(check_key)); 96 explicit_bzero(&shactx, sizeof(shactx)); 97 98 /* k = SHA1(mask_key) */ 99 SHA1Init(&shactx); 100 SHA1Update(&shactx, maskkey, maskkey_size); 101 SHA1Final(check_key, &shactx); 102 103 /* mac = HMAC_SHA1_k(unencrypted key) */ 104 hmac_sha1(key, key_size, check_key, sizeof(check_key), check_digest); 105 106 explicit_bzero(check_key, sizeof(check_key)); 107 explicit_bzero(&shactx, sizeof(shactx)); 108 } 109 110 int 111 sr_crypto_decrypt_keys(struct sr_boot_volume *bv) 112 { 113 struct sr_meta_crypto *cm; 114 struct sr_boot_keydisk *kd; 115 struct sr_meta_opt_item *omi; 116 struct sr_crypto_pbkdf *kdfhint; 117 struct sr_crypto_kdfinfo kdfinfo; 118 char passphrase[PASSPHRASE_LENGTH]; 119 u_int8_t digest[SHA1_DIGEST_LENGTH]; 120 u_int8_t *keys = NULL; 121 u_int8_t *kp, *cp; 122 rijndael_ctx ctx; 123 u_int32_t type; 124 int rv = -1; 125 int c, i; 126 127 SLIST_FOREACH(omi, &bv->sbv_meta_opt, omi_link) 128 if (omi->omi_som->som_type == SR_OPT_CRYPTO) 129 break; 130 131 if (omi == NULL) { 132 printf("Crypto metadata not found!\n"); 133 goto done; 134 } 135 136 cm = (struct sr_meta_crypto *)omi->omi_som; 137 kdfhint = (struct sr_crypto_pbkdf *)&cm->scm_kdfhint; 138 139 switch (cm->scm_mask_alg) { 140 case SR_CRYPTOM_AES_ECB_256: 141 break; 142 default: 143 printf("unsupported encryption algorithm %u\n", 144 cm->scm_mask_alg); 145 goto done; 146 } 147 148 SLIST_FOREACH(kd, &sr_keydisks, kd_link) { 149 if (bcmp(&kd->kd_uuid, &bv->sbv_uuid, sizeof(kd->kd_uuid)) == 0) 150 break; 151 } 152 if (kd) { 153 bcopy(&kd->kd_key, &kdfinfo.maskkey, sizeof(kdfinfo.maskkey)); 154 } else if (kdfhint->generic.type == SR_CRYPTOKDFT_KEYDISK) { 155 printf("keydisk not found\n"); 156 goto done; 157 } else { 158 if (kdfhint->generic.type != SR_CRYPTOKDFT_PKCS5_PBKDF2 && 159 kdfhint->generic.type != SR_CRYPTOKDFT_BCRYPT_PBKDF) { 160 printf("unknown KDF type %u\n", kdfhint->generic.type); 161 goto done; 162 } 163 164 printf("Passphrase: "); 165 for (i = 0; i < PASSPHRASE_LENGTH - 1; i++) { 166 c = cngetc(); 167 if (c == '\r' || c == '\n') 168 break; 169 else if (c == '\b') { 170 i = i > 0 ? i - 2 : -1; 171 continue; 172 } 173 passphrase[i] = (c & 0xff); 174 } 175 passphrase[i] = 0; 176 printf("\n"); 177 178 #ifdef DEBUG 179 printf("Got passphrase: %s with len %d\n", 180 passphrase, strlen(passphrase)); 181 #endif 182 183 type = kdfhint->generic.type; 184 if (type == SR_CRYPTOKDFT_PKCS5_PBKDF2) { 185 if (pkcs5_pbkdf2(passphrase, strlen(passphrase), 186 kdfhint->salt, sizeof(kdfhint->salt), 187 kdfinfo.maskkey, sizeof(kdfinfo.maskkey), 188 kdfhint->rounds) != 0) { 189 printf("pkcs5_pbkdf2 failed\n"); 190 goto done; 191 } 192 } else if (type == SR_CRYPTOKDFT_BCRYPT_PBKDF) { 193 if (bcrypt_pbkdf(passphrase, strlen(passphrase), 194 kdfhint->salt, sizeof(kdfhint->salt), 195 kdfinfo.maskkey, sizeof(kdfinfo.maskkey), 196 kdfhint->rounds) != 0) { 197 printf("bcrypt_pbkdf failed\n"); 198 goto done; 199 } 200 } else { 201 printf("unknown KDF type %u\n", kdfhint->generic.type); 202 goto done; 203 } 204 } 205 206 /* kdfinfo->maskkey now has key. */ 207 208 /* Decrypt disk keys. */ 209 keys = alloc(SR_CRYPTO_KEYBLOCK_BYTES); 210 bzero(keys, SR_CRYPTO_KEYBLOCK_BYTES); 211 212 if (rijndael_set_key(&ctx, kdfinfo.maskkey, 256) != 0) 213 goto done; 214 215 cp = (u_int8_t *)cm->scm_key; 216 kp = keys; 217 for (i = 0; i < SR_CRYPTO_KEYBLOCK_BYTES; i += RIJNDAEL128_BLOCK_LEN) 218 rijndael_decrypt(&ctx, (u_char *)(cp + i), (u_char *)(kp + i)); 219 220 /* Check that the key decrypted properly. */ 221 sr_crypto_calculate_check_hmac_sha1(kdfinfo.maskkey, 222 sizeof(kdfinfo.maskkey), keys, SR_CRYPTO_KEYBLOCK_BYTES, digest); 223 224 if (bcmp(digest, cm->chk_hmac_sha1.sch_mac, sizeof(digest))) { 225 printf("incorrect passphrase or keydisk\n"); 226 goto done; 227 } 228 229 /* Keys and keydisks will be cleared before boot and from _rtt. */ 230 bv->sbv_keys = keys; 231 bv->sbv_maskkey = alloc(sizeof(kdfinfo.maskkey)); 232 bcopy(&kdfinfo.maskkey, bv->sbv_maskkey, sizeof(kdfinfo.maskkey)); 233 234 rv = 0; 235 236 done: 237 explicit_bzero(passphrase, PASSPHRASE_LENGTH); 238 explicit_bzero(&kdfinfo, sizeof(kdfinfo)); 239 explicit_bzero(digest, sizeof(digest)); 240 241 if (keys != NULL && rv != 0) { 242 explicit_bzero(keys, SR_CRYPTO_KEYBLOCK_BYTES); 243 free(keys, SR_CRYPTO_KEYBLOCK_BYTES); 244 } 245 246 return (rv); 247 } 248