| 1 | |
| 2 | |
| 3 | * eCryptfs: Linux filesystem encryption layer
|
| 4 | * In-kernel key management code. Includes functions to parse and
|
| 5 | * write authentication token-related packets with the underlying
|
| 6 | * file.
|
| 7 | *
|
| 8 | * Copyright (C) 2004-2006 International Business Machines Corp.
|
| 9 | * Author(s): Michael A. Halcrow <[email protected]>
|
| 10 | * Michael C. Thompson <[email protected]>
|
| 11 | * Trevor S. Highland <[email protected]>
|
| 12 |
|
| 13 |
|
| 14 | #include <crypto/skcipher.h>
|
| 15 | #include <linux/string.h>
|
| 16 | #include <linux/pagemap.h>
|
| 17 | #include <linux/key.h>
|
| 18 | #include <linux/random.h>
|
| 19 | #include <linux/scatterlist.h>
|
| 20 | #include <linux/slab.h>
|
| 21 | #include "ecryptfs_kernel.h"
|
| 22 |
|
| 23 | |
| 24 | * request_key returned an error instead of a valid key address;
|
| 25 | * determine the type of error, make appropriate log entries, and
|
| 26 | * return an error code.
|
| 27 |
|
| 28 | static int process_request_key_err(long err_code)
|
| 29 | {
|
| 30 | int rc = 0;
|
| 31 |
|
| 32 | switch (err_code) {
|
| 33 | case -ENOKEY:
|
| 34 | ecryptfs_printk(KERN_WARNING, "No key\n");
|
| 35 | rc = -ENOENT;
|
| 36 | break;
|
| 37 | case -EKEYEXPIRED:
|
| 38 | ecryptfs_printk(KERN_WARNING, "Key expired\n");
|
| 39 | rc = -ETIME;
|
| 40 | break;
|
| 41 | case -EKEYREVOKED:
|
| 42 | ecryptfs_printk(KERN_WARNING, "Key revoked\n");
|
| 43 | rc = -EINVAL;
|
| 44 | break;
|
| 45 | default:
|
| 46 | ecryptfs_printk(KERN_WARNING, "Unknown error code: "
|
| 47 | "[0x%.16lx]\n", err_code);
|
| 48 | rc = -EINVAL;
|
| 49 | }
|
| 50 | return rc;
|
| 51 | }
|
| 52 |
|
| 53 | static int process_find_global_auth_tok_for_sig_err(int err_code)
|
| 54 | {
|
| 55 | int rc = err_code;
|
| 56 |
|
| 57 | switch (err_code) {
|
| 58 | case -ENOENT:
|
| 59 | ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
|
| 60 | break;
|
| 61 | case -EINVAL:
|
| 62 | ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
|
| 63 | break;
|
| 64 | default:
|
| 65 | rc = process_request_key_err(err_code);
|
| 66 | break;
|
| 67 | }
|
| 68 | return rc;
|
| 69 | }
|
| 70 |
|
| 71 | |
| 72 | * ecryptfs_parse_packet_length
|
| 73 | * @data: Pointer to memory containing length at offset
|
| 74 | * @size: This function writes the decoded size to this memory
|
| 75 | * address; zero on error
|
| 76 | * @length_size: The number of bytes occupied by the encoded length
|
| 77 | *
|
| 78 | * Returns zero on success; non-zero on error
|
| 79 |
|
| 80 | int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
|
| 81 | size_t *length_size)
|
| 82 | {
|
| 83 | int rc = 0;
|
| 84 |
|
| 85 | (*length_size) = 0;
|
| 86 | (*size) = 0;
|
| 87 | if (data[0] < 192) {
|
| 88 |
|
| 89 | (*size) = data[0];
|
| 90 | (*length_size) = 1;
|
| 91 | } else if (data[0] < 224) {
|
| 92 |
|
| 93 | (*size) = (data[0] - 192) * 256;
|
| 94 | (*size) += data[1] + 192;
|
| 95 | (*length_size) = 2;
|
| 96 | } else if (data[0] == 255) {
|
| 97 |
|
| 98 | ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
|
| 99 | "supported\n");
|
| 100 | rc = -EINVAL;
|
| 101 | goto out;
|
| 102 | } else {
|
| 103 | ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
|
| 104 | rc = -EINVAL;
|
| 105 | goto out;
|
| 106 | }
|
| 107 | out:
|
| 108 | return rc;
|
| 109 | }
|
| 110 |
|
| 111 | |
| 112 | * ecryptfs_write_packet_length
|
| 113 | * @dest: The byte array target into which to write the length. Must
|
| 114 | * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
|
| 115 | * @size: The length to write.
|
| 116 | * @packet_size_length: The number of bytes used to encode the packet
|
| 117 | * length is written to this address.
|
| 118 | *
|
| 119 | * Returns zero on success; non-zero on error.
|
| 120 |
|
| 121 | int ecryptfs_write_packet_length(char *dest, size_t size,
|
| 122 | size_t *packet_size_length)
|
| 123 | {
|
| 124 | int rc = 0;
|
| 125 |
|
| 126 | if (size < 192) {
|
| 127 | dest[0] = size;
|
| 128 | (*packet_size_length) = 1;
|
| 129 | } else if (size < 65536) {
|
| 130 | dest[0] = (((size - 192) / 256) + 192);
|
| 131 | dest[1] = ((size - 192) % 256);
|
| 132 | (*packet_size_length) = 2;
|
| 133 | } else {
|
| 134 |
|
| 135 | rc = -EINVAL;
|
| 136 | ecryptfs_printk(KERN_WARNING,
|
| 137 | "Unsupported packet size: [%zd]\n", size);
|
| 138 | }
|
| 139 | return rc;
|
| 140 | }
|
| 141 |
|
| 142 | static int
|
| 143 | write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
|
| 144 | char **packet, size_t *packet_len)
|
| 145 | {
|
| 146 | size_t i = 0;
|
| 147 | size_t data_len;
|
| 148 | size_t packet_size_len;
|
| 149 | char *message;
|
| 150 | int rc;
|
| 151 |
|
| 152 | |
| 153 | * ***** TAG 64 Packet Format *****
|
| 154 | * | Content Type | 1 byte |
|
| 155 | * | Key Identifier Size | 1 or 2 bytes |
|
| 156 | * | Key Identifier | arbitrary |
|
| 157 | * | Encrypted File Encryption Key Size | 1 or 2 bytes |
|
| 158 | * | Encrypted File Encryption Key | arbitrary |
|
| 159 |
|
| 160 | data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
|
| 161 | + session_key->encrypted_key_size);
|
| 162 | *packet = kmalloc(data_len, GFP_KERNEL);
|
| 163 | message = *packet;
|
| 164 | if (!message) {
|
| 165 | ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
|
| 166 | rc = -ENOMEM;
|
| 167 | goto out;
|
| 168 | }
|
| 169 | message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
|
| 170 | rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
|
| 171 | &packet_size_len);
|
| 172 | if (rc) {
|
| 173 | ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
|
| 174 | "header; cannot generate packet length\n");
|
| 175 | goto out;
|
| 176 | }
|
| 177 | i += packet_size_len;
|
| 178 | memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
|
| 179 | i += ECRYPTFS_SIG_SIZE_HEX;
|
| 180 | rc = ecryptfs_write_packet_length(&message[i],
|
| 181 | session_key->encrypted_key_size,
|
| 182 | &packet_size_len);
|
| 183 | if (rc) {
|
| 184 | ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
|
| 185 | "header; cannot generate packet length\n");
|
| 186 | goto out;
|
| 187 | }
|
| 188 | i += packet_size_len;
|
| 189 | memcpy(&message[i], session_key->encrypted_key,
|
| 190 | session_key->encrypted_key_size);
|
| 191 | i += session_key->encrypted_key_size;
|
| 192 | *packet_len = i;
|
| 193 | out:
|
| 194 | return rc;
|
| 195 | }
|
| 196 |
|
| 197 | static int
|
| 198 | parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
|
| 199 | struct ecryptfs_message *msg)
|
| 200 | {
|
| 201 | size_t i = 0;
|
| 202 | char *data;
|
| 203 | size_t data_len;
|
| 204 | size_t m_size;
|
| 205 | size_t message_len;
|
| 206 | u16 checksum = 0;
|
| 207 | u16 expected_checksum = 0;
|
| 208 | int rc;
|
| 209 |
|
| 210 | |
| 211 | * ***** TAG 65 Packet Format *****
|
| 212 | * | Content Type | 1 byte |
|
| 213 | * | Status Indicator | 1 byte |
|
| 214 | * | File Encryption Key Size | 1 or 2 bytes |
|
| 215 | * | File Encryption Key | arbitrary |
|
| 216 |
|
| 217 | message_len = msg->data_len;
|
| 218 | data = msg->data;
|
| 219 | if (message_len < 4) {
|
| 220 | rc = -EIO;
|
| 221 | goto out;
|
| 222 | }
|
| 223 | if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
|
| 224 | ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
|
| 225 | rc = -EIO;
|
| 226 | goto out;
|
| 227 | }
|
| 228 | if (data[i++]) {
|
| 229 | ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
|
| 230 | "[%d]\n", data[i-1]);
|
| 231 | rc = -EIO;
|
| 232 | goto out;
|
| 233 | }
|
| 234 | rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
|
| 235 | if (rc) {
|
| 236 | ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
|
| 237 | "rc = [%d]\n", rc);
|
| 238 | goto out;
|
| 239 | }
|
| 240 | i += data_len;
|
| 241 | if (message_len < (i + m_size)) {
|
| 242 | ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
|
| 243 | "is shorter than expected\n");
|
| 244 | rc = -EIO;
|
| 245 | goto out;
|
| 246 | }
|
| 247 | if (m_size < 3) {
|
| 248 | ecryptfs_printk(KERN_ERR,
|
| 249 | "The decrypted key is not long enough to "
|
| 250 | "include a cipher code and checksum\n");
|
| 251 | rc = -EIO;
|
| 252 | goto out;
|
| 253 | }
|
| 254 | *cipher_code = data[i++];
|
| 255 |
|
| 256 | session_key->decrypted_key_size = m_size - 3;
|
| 257 | if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
|
| 258 | ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
|
| 259 | "the maximum key size [%d]\n",
|
| 260 | session_key->decrypted_key_size,
|
| 261 | ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
|
| 262 | rc = -EIO;
|
| 263 | goto out;
|
| 264 | }
|
| 265 | memcpy(session_key->decrypted_key, &data[i],
|
| 266 | session_key->decrypted_key_size);
|
| 267 | i += session_key->decrypted_key_size;
|
| 268 | expected_checksum += (unsigned char)(data[i++]) << 8;
|
| 269 | expected_checksum += (unsigned char)(data[i++]);
|
| 270 | for (i = 0; i < session_key->decrypted_key_size; i++)
|
| 271 | checksum += session_key->decrypted_key[i];
|
| 272 | if (expected_checksum != checksum) {
|
| 273 | ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
|
| 274 | "encryption key; expected [%x]; calculated "
|
| 275 | "[%x]\n", expected_checksum, checksum);
|
| 276 | rc = -EIO;
|
| 277 | }
|
| 278 | out:
|
| 279 | return rc;
|
| 280 | }
|
| 281 |
|
| 282 |
|
| 283 | static int
|
| 284 | write_tag_66_packet(char *signature, u8 cipher_code,
|
| 285 | struct ecryptfs_crypt_stat *crypt_stat, char **packet,
|
| 286 | size_t *packet_len)
|
| 287 | {
|
| 288 | size_t i = 0;
|
| 289 | size_t j;
|
| 290 | size_t data_len;
|
| 291 | size_t checksum = 0;
|
| 292 | size_t packet_size_len;
|
| 293 | char *message;
|
| 294 | int rc;
|
| 295 |
|
| 296 | |
| 297 | * ***** TAG 66 Packet Format *****
|
| 298 | * | Content Type | 1 byte |
|
| 299 | * | Key Identifier Size | 1 or 2 bytes |
|
| 300 | * | Key Identifier | arbitrary |
|
| 301 | * | File Encryption Key Size | 1 or 2 bytes |
|
| 302 | * | Cipher Code | 1 byte |
|
| 303 | * | File Encryption Key | arbitrary |
|
| 304 | * | Checksum | 2 bytes |
|
| 305 |
|
| 306 | data_len = (8 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
|
| 307 | *packet = kmalloc(data_len, GFP_KERNEL);
|
| 308 | message = *packet;
|
| 309 | if (!message) {
|
| 310 | ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
|
| 311 | rc = -ENOMEM;
|
| 312 | goto out;
|
| 313 | }
|
| 314 | message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
|
| 315 | rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
|
| 316 | &packet_size_len);
|
| 317 | if (rc) {
|
| 318 | ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
|
| 319 | "header; cannot generate packet length\n");
|
| 320 | goto out;
|
| 321 | }
|
| 322 | i += packet_size_len;
|
| 323 | memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
|
| 324 | i += ECRYPTFS_SIG_SIZE_HEX;
|
| 325 |
|
| 326 | rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
|
| 327 | &packet_size_len);
|
| 328 | if (rc) {
|
| 329 | ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
|
| 330 | "header; cannot generate packet length\n");
|
| 331 | goto out;
|
| 332 | }
|
| 333 | i += packet_size_len;
|
| 334 | message[i++] = cipher_code;
|
| 335 | memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
|
| 336 | i += crypt_stat->key_size;
|
| 337 | for (j = 0; j < crypt_stat->key_size; j++)
|
| 338 | checksum += crypt_stat->key[j];
|
| 339 | message[i++] = (checksum / 256) % 256;
|
| 340 | message[i++] = (checksum % 256);
|
| 341 | *packet_len = i;
|
| 342 | out:
|
| 343 | return rc;
|
| 344 | }
|
| 345 |
|
| 346 | static int
|
| 347 | parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
|
| 348 | struct ecryptfs_message *msg)
|
| 349 | {
|
| 350 | size_t i = 0;
|
| 351 | char *data;
|
| 352 | size_t data_len;
|
| 353 | size_t message_len;
|
| 354 | int rc;
|
| 355 |
|
| 356 | |
| 357 | * ***** TAG 67 Packet Format *****
|
| 358 | * | Content Type | 1 byte |
|
| 359 | * | Status Indicator | 1 byte |
|
| 360 | * | Encrypted File Encryption Key Size | 1 or 2 bytes |
|
| 361 | * | Encrypted File Encryption Key | arbitrary |
|
| 362 |
|
| 363 | message_len = msg->data_len;
|
| 364 | data = msg->data;
|
| 365 |
|
| 366 | if (message_len < 4) {
|
| 367 | rc = -EIO;
|
| 368 | printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
|
| 369 | "message length is [%d]\n", __func__, message_len, 4);
|
| 370 | goto out;
|
| 371 | }
|
| 372 | if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
|
| 373 | rc = -EIO;
|
| 374 | printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
|
| 375 | __func__);
|
| 376 | goto out;
|
| 377 | }
|
| 378 | if (data[i++]) {
|
| 379 | rc = -EIO;
|
| 380 | printk(KERN_ERR "%s: Status indicator has non zero "
|
| 381 | "value [%d]\n", __func__, data[i-1]);
|
| 382 |
|
| 383 | goto out;
|
| 384 | }
|
| 385 | rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
|
| 386 | &data_len);
|
| 387 | if (rc) {
|
| 388 | ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
|
| 389 | "rc = [%d]\n", rc);
|
| 390 | goto out;
|
| 391 | }
|
| 392 | i += data_len;
|
| 393 | if (message_len < (i + key_rec->enc_key_size)) {
|
| 394 | rc = -EIO;
|
| 395 | printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
|
| 396 | __func__, message_len, (i + key_rec->enc_key_size));
|
| 397 | goto out;
|
| 398 | }
|
| 399 | if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
|
| 400 | rc = -EIO;
|
| 401 | printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
|
| 402 | "the maximum key size [%d]\n", __func__,
|
| 403 | key_rec->enc_key_size,
|
| 404 | ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
|
| 405 | goto out;
|
| 406 | }
|
| 407 | memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
|
| 408 | out:
|
| 409 | return rc;
|
| 410 | }
|
| 411 |
|
| 412 | |
| 413 | * ecryptfs_verify_version
|
| 414 | * @version: The version number to confirm
|
| 415 | *
|
| 416 | * Returns zero on good version; non-zero otherwise
|
| 417 |
|
| 418 | static int ecryptfs_verify_version(u16 version)
|
| 419 | {
|
| 420 | int rc = 0;
|
| 421 | unsigned char major;
|
| 422 | unsigned char minor;
|
| 423 |
|
| 424 | major = ((version >> 8) & 0xFF);
|
| 425 | minor = (version & 0xFF);
|
| 426 | if (major != ECRYPTFS_VERSION_MAJOR) {
|
| 427 | ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
|
| 428 | "Expected [%d]; got [%d]\n",
|
| 429 | ECRYPTFS_VERSION_MAJOR, major);
|
| 430 | rc = -EINVAL;
|
| 431 | goto out;
|
| 432 | }
|
| 433 | if (minor != ECRYPTFS_VERSION_MINOR) {
|
| 434 | ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
|
| 435 | "Expected [%d]; got [%d]\n",
|
| 436 | ECRYPTFS_VERSION_MINOR, minor);
|
| 437 | rc = -EINVAL;
|
| 438 | goto out;
|
| 439 | }
|
| 440 | out:
|
| 441 | return rc;
|
| 442 | }
|
| 443 |
|
| 444 | |
| 445 | * ecryptfs_verify_auth_tok_from_key
|
| 446 | * @auth_tok_key: key containing the authentication token
|
| 447 | * @auth_tok: authentication token
|
| 448 | *
|
| 449 | * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
|
| 450 | * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
|
| 451 |
|
| 452 | static int
|
| 453 | ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
|
| 454 | struct ecryptfs_auth_tok **auth_tok)
|
| 455 | {
|
| 456 | int rc = 0;
|
| 457 |
|
| 458 | (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
|
| 459 | if (IS_ERR(*auth_tok)) {
|
| 460 | rc = PTR_ERR(*auth_tok);
|
| 461 | *auth_tok = NULL;
|
| 462 | goto out;
|
| 463 | }
|
| 464 |
|
| 465 | if (ecryptfs_verify_version((*auth_tok)->version)) {
|
| 466 | printk(KERN_ERR "Data structure version mismatch. Userspace "
|
| 467 | "tools must match eCryptfs kernel module with major "
|
| 468 | "version [%d] and minor version [%d]\n",
|
| 469 | ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
|
| 470 | rc = -EINVAL;
|
| 471 | goto out;
|
| 472 | }
|
| 473 | if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
|
| 474 | && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
|
| 475 | printk(KERN_ERR "Invalid auth_tok structure "
|
| 476 | "returned from key query\n");
|
| 477 | rc = -EINVAL;
|
| 478 | goto out;
|
| 479 | }
|
| 480 | out:
|
| 481 | return rc;
|
| 482 | }
|
| 483 |
|
| 484 | static int
|
| 485 | ecryptfs_find_global_auth_tok_for_sig(
|
| 486 | struct key **auth_tok_key,
|
| 487 | struct ecryptfs_auth_tok **auth_tok,
|
| 488 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
|
| 489 | {
|
| 490 | struct ecryptfs_global_auth_tok *walker;
|
| 491 | int rc = 0;
|
| 492 |
|
| 493 | (*auth_tok_key) = NULL;
|
| 494 | (*auth_tok) = NULL;
|
| 495 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
|
| 496 | list_for_each_entry(walker,
|
| 497 | &mount_crypt_stat->global_auth_tok_list,
|
| 498 | mount_crypt_stat_list) {
|
| 499 | if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
|
| 500 | continue;
|
| 501 |
|
| 502 | if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
|
| 503 | rc = -EINVAL;
|
| 504 | goto out;
|
| 505 | }
|
| 506 |
|
| 507 | rc = key_validate(walker->global_auth_tok_key);
|
| 508 | if (rc) {
|
| 509 | if (rc == -EKEYEXPIRED)
|
| 510 | goto out;
|
| 511 | goto out_invalid_auth_tok;
|
| 512 | }
|
| 513 |
|
| 514 | down_write(&(walker->global_auth_tok_key->sem));
|
| 515 | rc = ecryptfs_verify_auth_tok_from_key(
|
| 516 | walker->global_auth_tok_key, auth_tok);
|
| 517 | if (rc)
|
| 518 | goto out_invalid_auth_tok_unlock;
|
| 519 |
|
| 520 | (*auth_tok_key) = walker->global_auth_tok_key;
|
| 521 | key_get(*auth_tok_key);
|
| 522 | goto out;
|
| 523 | }
|
| 524 | rc = -ENOENT;
|
| 525 | goto out;
|
| 526 | out_invalid_auth_tok_unlock:
|
| 527 | up_write(&(walker->global_auth_tok_key->sem));
|
| 528 | out_invalid_auth_tok:
|
| 529 | printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
|
| 530 | walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
|
| 531 | key_put(walker->global_auth_tok_key);
|
| 532 | walker->global_auth_tok_key = NULL;
|
| 533 | out:
|
| 534 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
|
| 535 | return rc;
|
| 536 | }
|
| 537 |
|
| 538 | |
| 539 | * ecryptfs_find_auth_tok_for_sig
|
| 540 | * @auth_tok_key: key containing the authentication token
|
| 541 | * @auth_tok: Set to the matching auth_tok; NULL if not found
|
| 542 | * @mount_crypt_stat: inode crypt_stat crypto context
|
| 543 | * @sig: Sig of auth_tok to find
|
| 544 | *
|
| 545 | * For now, this function simply looks at the registered auth_tok's
|
| 546 | * linked off the mount_crypt_stat, so all the auth_toks that can be
|
| 547 | * used must be registered at mount time. This function could
|
| 548 | * potentially try a lot harder to find auth_tok's (e.g., by calling
|
| 549 | * out to ecryptfsd to dynamically retrieve an auth_tok object) so
|
| 550 | * that static registration of auth_tok's will no longer be necessary.
|
| 551 | *
|
| 552 | * Returns zero on no error; non-zero on error
|
| 553 |
|
| 554 | static int
|
| 555 | ecryptfs_find_auth_tok_for_sig(
|
| 556 | struct key **auth_tok_key,
|
| 557 | struct ecryptfs_auth_tok **auth_tok,
|
| 558 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
|
| 559 | char *sig)
|
| 560 | {
|
| 561 | int rc = 0;
|
| 562 |
|
| 563 | rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
|
| 564 | mount_crypt_stat, sig);
|
| 565 | if (rc == -ENOENT) {
|
| 566 | |
| 567 | * mount_crypt_stat structure, we prevent to use auth toks that
|
| 568 | * are not inserted through the ecryptfs_add_global_auth_tok
|
| 569 | * function.
|
| 570 |
|
| 571 | if (mount_crypt_stat->flags
|
| 572 | & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
|
| 573 | return -EINVAL;
|
| 574 |
|
| 575 | rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
|
| 576 | sig);
|
| 577 | }
|
| 578 | return rc;
|
| 579 | }
|
| 580 |
|
| 581 | |
| 582 | * write_tag_70_packet can gobble a lot of stack space. We stuff most
|
| 583 | * of the function's parameters in a kmalloc'd struct to help reduce
|
| 584 | * eCryptfs' overall stack usage.
|
| 585 |
|
| 586 | struct ecryptfs_write_tag_70_packet_silly_stack {
|
| 587 | u8 cipher_code;
|
| 588 | size_t max_packet_size;
|
| 589 | size_t packet_size_len;
|
| 590 | size_t block_aligned_filename_size;
|
| 591 | size_t block_size;
|
| 592 | size_t i;
|
| 593 | size_t j;
|
| 594 | size_t num_rand_bytes;
|
| 595 | struct mutex *tfm_mutex;
|
| 596 | char *block_aligned_filename;
|
| 597 | struct ecryptfs_auth_tok *auth_tok;
|
| 598 | struct scatterlist src_sg[2];
|
| 599 | struct scatterlist dst_sg[2];
|
| 600 | struct crypto_skcipher *skcipher_tfm;
|
| 601 | struct skcipher_request *skcipher_req;
|
| 602 | char iv[ECRYPTFS_MAX_IV_BYTES];
|
| 603 | char hash[MD5_DIGEST_SIZE];
|
| 604 | };
|
| 605 |
|
| 606 | |
| 607 | * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
|
| 608 | * @filename: NULL-terminated filename string
|
| 609 | *
|
| 610 | * This is the simplest mechanism for achieving filename encryption in
|
| 611 | * eCryptfs. It encrypts the given filename with the mount-wide
|
| 612 | * filename encryption key (FNEK) and stores it in a packet to @dest,
|
| 613 | * which the callee will encode and write directly into the dentry
|
| 614 | * name.
|
| 615 |
|
| 616 | int
|
| 617 | ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
|
| 618 | size_t *packet_size,
|
| 619 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
|
| 620 | char *filename, size_t filename_size)
|
| 621 | {
|
| 622 | struct ecryptfs_write_tag_70_packet_silly_stack *s;
|
| 623 | struct key *auth_tok_key = NULL;
|
| 624 | int rc = 0;
|
| 625 |
|
| 626 | s = kzalloc_obj(*s);
|
| 627 | if (!s)
|
| 628 | return -ENOMEM;
|
| 629 |
|
| 630 | (*packet_size) = 0;
|
| 631 | rc = ecryptfs_find_auth_tok_for_sig(
|
| 632 | &auth_tok_key,
|
| 633 | &s->auth_tok, mount_crypt_stat,
|
| 634 | mount_crypt_stat->global_default_fnek_sig);
|
| 635 | if (rc) {
|
| 636 | printk(KERN_ERR "%s: Error attempting to find auth tok for "
|
| 637 | "fnek sig [%s]; rc = [%d]\n", __func__,
|
| 638 | mount_crypt_stat->global_default_fnek_sig, rc);
|
| 639 | goto out;
|
| 640 | }
|
| 641 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
|
| 642 | &s->skcipher_tfm,
|
| 643 | &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
|
| 644 | if (unlikely(rc)) {
|
| 645 | printk(KERN_ERR "Internal error whilst attempting to get "
|
| 646 | "tfm and mutex for cipher name [%s]; rc = [%d]\n",
|
| 647 | mount_crypt_stat->global_default_fn_cipher_name, rc);
|
| 648 | goto out;
|
| 649 | }
|
| 650 | mutex_lock(s->tfm_mutex);
|
| 651 | s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
|
| 652 | |
| 653 | * and the plaintext filename
|
| 654 | s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
|
| 655 | s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
|
| 656 | if ((s->block_aligned_filename_size % s->block_size) != 0) {
|
| 657 | s->num_rand_bytes += (s->block_size
|
| 658 | - (s->block_aligned_filename_size
|
| 659 | % s->block_size));
|
| 660 | s->block_aligned_filename_size = (s->num_rand_bytes
|
| 661 | + filename_size);
|
| 662 | }
|
| 663 | |
| 664 | * Octets 1-N1: Tag 70 packet size (includes cipher identifier
|
| 665 | * and block-aligned encrypted filename size)
|
| 666 | * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
|
| 667 | * Octet N2-N3: Cipher identifier (1 octet)
|
| 668 | * Octets N3-N4: Block-aligned encrypted filename
|
| 669 | * - Consists of a minimum number of random characters, a \0
|
| 670 | * separator, and then the filename
|
| 671 | s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
|
| 672 | + s->block_aligned_filename_size);
|
| 673 | if (!dest) {
|
| 674 | (*packet_size) = s->max_packet_size;
|
| 675 | goto out_unlock;
|
| 676 | }
|
| 677 | if (s->max_packet_size > (*remaining_bytes)) {
|
| 678 | printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
|
| 679 | "[%zd] available\n", __func__, s->max_packet_size,
|
| 680 | (*remaining_bytes));
|
| 681 | rc = -EINVAL;
|
| 682 | goto out_unlock;
|
| 683 | }
|
| 684 |
|
| 685 | s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
|
| 686 | if (!s->skcipher_req) {
|
| 687 | printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
|
| 688 | "skcipher_request_alloc for %s\n", __func__,
|
| 689 | crypto_skcipher_driver_name(s->skcipher_tfm));
|
| 690 | rc = -ENOMEM;
|
| 691 | goto out_unlock;
|
| 692 | }
|
| 693 |
|
| 694 | skcipher_request_set_callback(s->skcipher_req,
|
| 695 | CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
|
| 696 |
|
| 697 | s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
|
| 698 | GFP_KERNEL);
|
| 699 | if (!s->block_aligned_filename) {
|
| 700 | rc = -ENOMEM;
|
| 701 | goto out_unlock;
|
| 702 | }
|
| 703 | dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
|
| 704 | rc = ecryptfs_write_packet_length(&dest[s->i],
|
| 705 | (ECRYPTFS_SIG_SIZE
|
| 706 | + 1
|
| 707 | + s->block_aligned_filename_size),
|
| 708 | &s->packet_size_len);
|
| 709 | if (rc) {
|
| 710 | printk(KERN_ERR "%s: Error generating tag 70 packet "
|
| 711 | "header; cannot generate packet length; rc = [%d]\n",
|
| 712 | __func__, rc);
|
| 713 | goto out_free_unlock;
|
| 714 | }
|
| 715 | s->i += s->packet_size_len;
|
| 716 | ecryptfs_from_hex(&dest[s->i],
|
| 717 | mount_crypt_stat->global_default_fnek_sig,
|
| 718 | ECRYPTFS_SIG_SIZE);
|
| 719 | s->i += ECRYPTFS_SIG_SIZE;
|
| 720 | s->cipher_code = ecryptfs_code_for_cipher_string(
|
| 721 | mount_crypt_stat->global_default_fn_cipher_name,
|
| 722 | mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
| 723 | if (s->cipher_code == 0) {
|
| 724 | printk(KERN_WARNING "%s: Unable to generate code for "
|
| 725 | "cipher [%s] with key bytes [%zd]\n", __func__,
|
| 726 | mount_crypt_stat->global_default_fn_cipher_name,
|
| 727 | mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
| 728 | rc = -EINVAL;
|
| 729 | goto out_free_unlock;
|
| 730 | }
|
| 731 | dest[s->i++] = s->cipher_code;
|
| 732 | |
| 733 | * filename encryption
|
| 734 | if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
|
| 735 | rc = -EOPNOTSUPP;
|
| 736 | printk(KERN_INFO "%s: Filename encryption only supports "
|
| 737 | "password tokens\n", __func__);
|
| 738 | goto out_free_unlock;
|
| 739 | }
|
| 740 |
|
| 741 | md5(s->auth_tok->token.password.session_key_encryption_key,
|
| 742 | s->auth_tok->token.password.session_key_encryption_key_bytes,
|
| 743 | s->hash);
|
| 744 | for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
|
| 745 | s->block_aligned_filename[s->j] =
|
| 746 | s->hash[s->j % MD5_DIGEST_SIZE];
|
| 747 | if ((s->j % MD5_DIGEST_SIZE) == (MD5_DIGEST_SIZE - 1))
|
| 748 | md5(s->hash, MD5_DIGEST_SIZE, s->hash);
|
| 749 | if (s->block_aligned_filename[s->j] == '\0')
|
| 750 | s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
|
| 751 | }
|
| 752 | memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
|
| 753 | filename_size);
|
| 754 | rc = virt_to_scatterlist(s->block_aligned_filename,
|
| 755 | s->block_aligned_filename_size, s->src_sg, 2);
|
| 756 | if (rc < 1) {
|
| 757 | printk(KERN_ERR "%s: Internal error whilst attempting to "
|
| 758 | "convert filename memory to scatterlist; rc = [%d]. "
|
| 759 | "block_aligned_filename_size = [%zd]\n", __func__, rc,
|
| 760 | s->block_aligned_filename_size);
|
| 761 | goto out_free_unlock;
|
| 762 | }
|
| 763 | rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
|
| 764 | s->dst_sg, 2);
|
| 765 | if (rc < 1) {
|
| 766 | printk(KERN_ERR "%s: Internal error whilst attempting to "
|
| 767 | "convert encrypted filename memory to scatterlist; "
|
| 768 | "rc = [%d]. block_aligned_filename_size = [%zd]\n",
|
| 769 | __func__, rc, s->block_aligned_filename_size);
|
| 770 | goto out_free_unlock;
|
| 771 | }
|
| 772 | |
| 773 | * of the IV here, so we just use 0's for the IV. Note the
|
| 774 | * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
|
| 775 | * >= ECRYPTFS_MAX_IV_BYTES.
|
| 776 | rc = crypto_skcipher_setkey(
|
| 777 | s->skcipher_tfm,
|
| 778 | s->auth_tok->token.password.session_key_encryption_key,
|
| 779 | mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
| 780 | if (rc < 0) {
|
| 781 | printk(KERN_ERR "%s: Error setting key for crypto context; "
|
| 782 | "rc = [%d]. s->auth_tok->token.password.session_key_"
|
| 783 | "encryption_key = [0x%p]; mount_crypt_stat->"
|
| 784 | "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
|
| 785 | rc,
|
| 786 | s->auth_tok->token.password.session_key_encryption_key,
|
| 787 | mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
| 788 | goto out_free_unlock;
|
| 789 | }
|
| 790 | skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
|
| 791 | s->block_aligned_filename_size, s->iv);
|
| 792 | rc = crypto_skcipher_encrypt(s->skcipher_req);
|
| 793 | if (rc) {
|
| 794 | printk(KERN_ERR "%s: Error attempting to encrypt filename; "
|
| 795 | "rc = [%d]\n", __func__, rc);
|
| 796 | goto out_free_unlock;
|
| 797 | }
|
| 798 | s->i += s->block_aligned_filename_size;
|
| 799 | (*packet_size) = s->i;
|
| 800 | (*remaining_bytes) -= (*packet_size);
|
| 801 | out_free_unlock:
|
| 802 | kfree_sensitive(s->block_aligned_filename);
|
| 803 | out_unlock:
|
| 804 | mutex_unlock(s->tfm_mutex);
|
| 805 | out:
|
| 806 | if (auth_tok_key) {
|
| 807 | up_write(&(auth_tok_key->sem));
|
| 808 | key_put(auth_tok_key);
|
| 809 | }
|
| 810 | skcipher_request_free(s->skcipher_req);
|
| 811 | kfree(s);
|
| 812 | return rc;
|
| 813 | }
|
| 814 |
|
| 815 | struct ecryptfs_parse_tag_70_packet_silly_stack {
|
| 816 | u8 cipher_code;
|
| 817 | size_t max_packet_size;
|
| 818 | size_t packet_size_len;
|
| 819 | size_t parsed_tag_70_packet_size;
|
| 820 | size_t block_aligned_filename_size;
|
| 821 | size_t block_size;
|
| 822 | size_t i;
|
| 823 | struct mutex *tfm_mutex;
|
| 824 | char *decrypted_filename;
|
| 825 | struct ecryptfs_auth_tok *auth_tok;
|
| 826 | struct scatterlist src_sg[2];
|
| 827 | struct scatterlist dst_sg[2];
|
| 828 | struct crypto_skcipher *skcipher_tfm;
|
| 829 | struct skcipher_request *skcipher_req;
|
| 830 | char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
|
| 831 | char iv[ECRYPTFS_MAX_IV_BYTES];
|
| 832 | char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
|
| 833 | };
|
| 834 |
|
| 835 | |
| 836 | * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
|
| 837 | * @filename: This function kmalloc's the memory for the filename
|
| 838 | * @filename_size: This function sets this to the amount of memory
|
| 839 | * kmalloc'd for the filename
|
| 840 | * @packet_size: This function sets this to the number of octets
|
| 841 | * in the packet parsed
|
| 842 | * @mount_crypt_stat: The mount-wide cryptographic context
|
| 843 | * @data: The memory location containing the start of the tag 70
|
| 844 | * packet
|
| 845 | * @max_packet_size: The maximum legal size of the packet to be parsed
|
| 846 | * from @data
|
| 847 | *
|
| 848 | * Returns zero on success; non-zero otherwise
|
| 849 |
|
| 850 | int
|
| 851 | ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
|
| 852 | size_t *packet_size,
|
| 853 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
|
| 854 | char *data, size_t max_packet_size)
|
| 855 | {
|
| 856 | struct ecryptfs_parse_tag_70_packet_silly_stack *s;
|
| 857 | struct key *auth_tok_key = NULL;
|
| 858 | int rc = 0;
|
| 859 |
|
| 860 | (*packet_size) = 0;
|
| 861 | (*filename_size) = 0;
|
| 862 | (*filename) = NULL;
|
| 863 | s = kzalloc_obj(*s);
|
| 864 | if (!s)
|
| 865 | return -ENOMEM;
|
| 866 |
|
| 867 | if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
|
| 868 | printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
|
| 869 | "at least [%d]\n", __func__, max_packet_size,
|
| 870 | ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
|
| 871 | rc = -EINVAL;
|
| 872 | goto out;
|
| 873 | }
|
| 874 | |
| 875 | * Octets 1-N1: Tag 70 packet size (includes cipher identifier
|
| 876 | * and block-aligned encrypted filename size)
|
| 877 | * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
|
| 878 | * Octet N2-N3: Cipher identifier (1 octet)
|
| 879 | * Octets N3-N4: Block-aligned encrypted filename
|
| 880 | * - Consists of a minimum number of random numbers, a \0
|
| 881 | * separator, and then the filename
|
| 882 | if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
|
| 883 | printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
|
| 884 | "tag [0x%.2x]\n", __func__,
|
| 885 | data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
|
| 886 | rc = -EINVAL;
|
| 887 | goto out;
|
| 888 | }
|
| 889 | rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
|
| 890 | &s->parsed_tag_70_packet_size,
|
| 891 | &s->packet_size_len);
|
| 892 | if (rc) {
|
| 893 | printk(KERN_WARNING "%s: Error parsing packet length; "
|
| 894 | "rc = [%d]\n", __func__, rc);
|
| 895 | goto out;
|
| 896 | }
|
| 897 | if (s->parsed_tag_70_packet_size < (ECRYPTFS_SIG_SIZE + 2)) {
|
| 898 | ecryptfs_printk(KERN_WARNING, "Invalid packet size [%zd]\n",
|
| 899 | s->parsed_tag_70_packet_size);
|
| 900 | rc = -EINVAL;
|
| 901 | goto out;
|
| 902 | }
|
| 903 | s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
|
| 904 | - ECRYPTFS_SIG_SIZE - 1);
|
| 905 | if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
|
| 906 | > max_packet_size) {
|
| 907 | printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
|
| 908 | "size is [%zd]\n", __func__, max_packet_size,
|
| 909 | (1 + s->packet_size_len + 1
|
| 910 | + s->block_aligned_filename_size));
|
| 911 | rc = -EINVAL;
|
| 912 | goto out;
|
| 913 | }
|
| 914 | (*packet_size) += s->packet_size_len;
|
| 915 | ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
|
| 916 | ECRYPTFS_SIG_SIZE);
|
| 917 | (*packet_size) += ECRYPTFS_SIG_SIZE;
|
| 918 | s->cipher_code = data[(*packet_size)++];
|
| 919 | rc = ecryptfs_cipher_code_to_string(s->cipher_string,
|
| 920 | sizeof(s->cipher_string),
|
| 921 | s->cipher_code);
|
| 922 | if (rc) {
|
| 923 | printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
|
| 924 | __func__, s->cipher_code);
|
| 925 | goto out;
|
| 926 | }
|
| 927 | rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
|
| 928 | &s->auth_tok, mount_crypt_stat,
|
| 929 | s->fnek_sig_hex);
|
| 930 | if (rc) {
|
| 931 | printk(KERN_ERR "%s: Error attempting to find auth tok for "
|
| 932 | "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
|
| 933 | rc);
|
| 934 | goto out;
|
| 935 | }
|
| 936 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
|
| 937 | &s->tfm_mutex,
|
| 938 | s->cipher_string);
|
| 939 | if (unlikely(rc)) {
|
| 940 | printk(KERN_ERR "Internal error whilst attempting to get "
|
| 941 | "tfm and mutex for cipher name [%s]; rc = [%d]\n",
|
| 942 | s->cipher_string, rc);
|
| 943 | goto out;
|
| 944 | }
|
| 945 | mutex_lock(s->tfm_mutex);
|
| 946 | rc = virt_to_scatterlist(&data[(*packet_size)],
|
| 947 | s->block_aligned_filename_size, s->src_sg, 2);
|
| 948 | if (rc < 1) {
|
| 949 | printk(KERN_ERR "%s: Internal error whilst attempting to "
|
| 950 | "convert encrypted filename memory to scatterlist; "
|
| 951 | "rc = [%d]. block_aligned_filename_size = [%zd]\n",
|
| 952 | __func__, rc, s->block_aligned_filename_size);
|
| 953 | goto out_unlock;
|
| 954 | }
|
| 955 | (*packet_size) += s->block_aligned_filename_size;
|
| 956 | s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
|
| 957 | GFP_KERNEL);
|
| 958 | if (!s->decrypted_filename) {
|
| 959 | rc = -ENOMEM;
|
| 960 | goto out_unlock;
|
| 961 | }
|
| 962 | rc = virt_to_scatterlist(s->decrypted_filename,
|
| 963 | s->block_aligned_filename_size, s->dst_sg, 2);
|
| 964 | if (rc < 1) {
|
| 965 | printk(KERN_ERR "%s: Internal error whilst attempting to "
|
| 966 | "convert decrypted filename memory to scatterlist; "
|
| 967 | "rc = [%d]. block_aligned_filename_size = [%zd]\n",
|
| 968 | __func__, rc, s->block_aligned_filename_size);
|
| 969 | goto out_free_unlock;
|
| 970 | }
|
| 971 |
|
| 972 | s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
|
| 973 | if (!s->skcipher_req) {
|
| 974 | printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
|
| 975 | "skcipher_request_alloc for %s\n", __func__,
|
| 976 | crypto_skcipher_driver_name(s->skcipher_tfm));
|
| 977 | rc = -ENOMEM;
|
| 978 | goto out_free_unlock;
|
| 979 | }
|
| 980 |
|
| 981 | skcipher_request_set_callback(s->skcipher_req,
|
| 982 | CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
|
| 983 |
|
| 984 | |
| 985 | * the IV here, so we just use 0's for the IV. Note the
|
| 986 | * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
|
| 987 | * >= ECRYPTFS_MAX_IV_BYTES.
|
| 988 | |
| 989 | * filename encryption
|
| 990 | if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
|
| 991 | rc = -EOPNOTSUPP;
|
| 992 | printk(KERN_INFO "%s: Filename encryption only supports "
|
| 993 | "password tokens\n", __func__);
|
| 994 | goto out_free_unlock;
|
| 995 | }
|
| 996 | rc = crypto_skcipher_setkey(
|
| 997 | s->skcipher_tfm,
|
| 998 | s->auth_tok->token.password.session_key_encryption_key,
|
| 999 | mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
| 1000 | if (rc < 0) {
|
| 1001 | printk(KERN_ERR "%s: Error setting key for crypto context; "
|
| 1002 | "rc = [%d]. s->auth_tok->token.password.session_key_"
|
| 1003 | "encryption_key = [0x%p]; mount_crypt_stat->"
|
| 1004 | "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
|
| 1005 | rc,
|
| 1006 | s->auth_tok->token.password.session_key_encryption_key,
|
| 1007 | mount_crypt_stat->global_default_fn_cipher_key_bytes);
|
| 1008 | goto out_free_unlock;
|
| 1009 | }
|
| 1010 | skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
|
| 1011 | s->block_aligned_filename_size, s->iv);
|
| 1012 | rc = crypto_skcipher_decrypt(s->skcipher_req);
|
| 1013 | if (rc) {
|
| 1014 | printk(KERN_ERR "%s: Error attempting to decrypt filename; "
|
| 1015 | "rc = [%d]\n", __func__, rc);
|
| 1016 | goto out_free_unlock;
|
| 1017 | }
|
| 1018 |
|
| 1019 | while (s->i < s->block_aligned_filename_size &&
|
| 1020 | s->decrypted_filename[s->i] != '\0')
|
| 1021 | s->i++;
|
| 1022 | if (s->i == s->block_aligned_filename_size) {
|
| 1023 | printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
|
| 1024 | "find valid separator between random characters and "
|
| 1025 | "the filename\n", __func__);
|
| 1026 | rc = -EINVAL;
|
| 1027 | goto out_free_unlock;
|
| 1028 | }
|
| 1029 | s->i++;
|
| 1030 | (*filename_size) = (s->block_aligned_filename_size - s->i);
|
| 1031 | if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
|
| 1032 | printk(KERN_WARNING "%s: Filename size is [%zd], which is "
|
| 1033 | "invalid\n", __func__, (*filename_size));
|
| 1034 | rc = -EINVAL;
|
| 1035 | goto out_free_unlock;
|
| 1036 | }
|
| 1037 | (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
|
| 1038 | if (!(*filename)) {
|
| 1039 | rc = -ENOMEM;
|
| 1040 | goto out_free_unlock;
|
| 1041 | }
|
| 1042 | memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
|
| 1043 | (*filename)[(*filename_size)] = '\0';
|
| 1044 | out_free_unlock:
|
| 1045 | kfree(s->decrypted_filename);
|
| 1046 | out_unlock:
|
| 1047 | mutex_unlock(s->tfm_mutex);
|
| 1048 | out:
|
| 1049 | if (rc) {
|
| 1050 | (*packet_size) = 0;
|
| 1051 | (*filename_size) = 0;
|
| 1052 | (*filename) = NULL;
|
| 1053 | }
|
| 1054 | if (auth_tok_key) {
|
| 1055 | up_write(&(auth_tok_key->sem));
|
| 1056 | key_put(auth_tok_key);
|
| 1057 | }
|
| 1058 | skcipher_request_free(s->skcipher_req);
|
| 1059 | kfree(s);
|
| 1060 | return rc;
|
| 1061 | }
|
| 1062 |
|
| 1063 | static int
|
| 1064 | ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
|
| 1065 | {
|
| 1066 | int rc = 0;
|
| 1067 |
|
| 1068 | (*sig) = NULL;
|
| 1069 | switch (auth_tok->token_type) {
|
| 1070 | case ECRYPTFS_PASSWORD:
|
| 1071 | (*sig) = auth_tok->token.password.signature;
|
| 1072 | break;
|
| 1073 | case ECRYPTFS_PRIVATE_KEY:
|
| 1074 | (*sig) = auth_tok->token.private_key.signature;
|
| 1075 | break;
|
| 1076 | default:
|
| 1077 | printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
|
| 1078 | auth_tok->token_type);
|
| 1079 | rc = -EINVAL;
|
| 1080 | }
|
| 1081 | return rc;
|
| 1082 | }
|
| 1083 |
|
| 1084 | |
| 1085 | * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
|
| 1086 | * @auth_tok: The key authentication token used to decrypt the session key
|
| 1087 | * @crypt_stat: The cryptographic context
|
| 1088 | *
|
| 1089 | * Returns zero on success; non-zero error otherwise.
|
| 1090 |
|
| 1091 | static int
|
| 1092 | decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
|
| 1093 | struct ecryptfs_crypt_stat *crypt_stat)
|
| 1094 | {
|
| 1095 | u8 cipher_code = 0;
|
| 1096 | struct ecryptfs_msg_ctx *msg_ctx;
|
| 1097 | struct ecryptfs_message *msg = NULL;
|
| 1098 | char *auth_tok_sig;
|
| 1099 | char *payload = NULL;
|
| 1100 | size_t payload_len = 0;
|
| 1101 | int rc;
|
| 1102 |
|
| 1103 | rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
|
| 1104 | if (rc) {
|
| 1105 | printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
|
| 1106 | auth_tok->token_type);
|
| 1107 | goto out;
|
| 1108 | }
|
| 1109 | rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
|
| 1110 | &payload, &payload_len);
|
| 1111 | if (rc) {
|
| 1112 | ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
|
| 1113 | goto out;
|
| 1114 | }
|
| 1115 | rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
|
| 1116 | if (rc) {
|
| 1117 | ecryptfs_printk(KERN_ERR, "Error sending message to "
|
| 1118 | "ecryptfsd: %d\n", rc);
|
| 1119 | goto out;
|
| 1120 | }
|
| 1121 | rc = ecryptfs_wait_for_response(msg_ctx, &msg);
|
| 1122 | if (rc) {
|
| 1123 | ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
|
| 1124 | "from the user space daemon\n");
|
| 1125 | rc = -EIO;
|
| 1126 | goto out;
|
| 1127 | }
|
| 1128 | rc = parse_tag_65_packet(&(auth_tok->session_key),
|
| 1129 | &cipher_code, msg);
|
| 1130 | if (rc) {
|
| 1131 | printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
|
| 1132 | rc);
|
| 1133 | goto out;
|
| 1134 | }
|
| 1135 | auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
|
| 1136 | memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
|
| 1137 | auth_tok->session_key.decrypted_key_size);
|
| 1138 | crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
|
| 1139 | rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
|
| 1140 | sizeof(crypt_stat->cipher),
|
| 1141 | cipher_code);
|
| 1142 | if (rc) {
|
| 1143 | ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
|
| 1144 | cipher_code);
|
| 1145 | goto out;
|
| 1146 | }
|
| 1147 | crypt_stat->flags |= ECRYPTFS_KEY_VALID;
|
| 1148 | if (ecryptfs_verbosity > 0) {
|
| 1149 | ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
|
| 1150 | ecryptfs_dump_hex(crypt_stat->key,
|
| 1151 | crypt_stat->key_size);
|
| 1152 | }
|
| 1153 | out:
|
| 1154 | kfree(msg);
|
| 1155 | kfree(payload);
|
| 1156 | return rc;
|
| 1157 | }
|
| 1158 |
|
| 1159 | static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
|
| 1160 | {
|
| 1161 | struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
|
| 1162 | struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
|
| 1163 |
|
| 1164 | list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
|
| 1165 | auth_tok_list_head, list) {
|
| 1166 | list_del(&auth_tok_list_item->list);
|
| 1167 | kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
|
| 1168 | auth_tok_list_item);
|
| 1169 | }
|
| 1170 | }
|
| 1171 |
|
| 1172 | struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
|
| 1173 |
|
| 1174 | |
| 1175 | * parse_tag_1_packet
|
| 1176 | * @crypt_stat: The cryptographic context to modify based on packet contents
|
| 1177 | * @data: The raw bytes of the packet.
|
| 1178 | * @auth_tok_list: eCryptfs parses packets into authentication tokens;
|
| 1179 | * a new authentication token will be placed at the
|
| 1180 | * end of this list for this packet.
|
| 1181 | * @new_auth_tok: Pointer to a pointer to memory that this function
|
| 1182 | * allocates; sets the memory address of the pointer to
|
| 1183 | * NULL on error. This object is added to the
|
| 1184 | * auth_tok_list.
|
| 1185 | * @packet_size: This function writes the size of the parsed packet
|
| 1186 | * into this memory location; zero on error.
|
| 1187 | * @max_packet_size: The maximum allowable packet size
|
| 1188 | *
|
| 1189 | * Returns zero on success; non-zero on error.
|
| 1190 |
|
| 1191 | static int
|
| 1192 | parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
|
| 1193 | unsigned char *data, struct list_head *auth_tok_list,
|
| 1194 | struct ecryptfs_auth_tok **new_auth_tok,
|
| 1195 | size_t *packet_size, size_t max_packet_size)
|
| 1196 | {
|
| 1197 | size_t body_size;
|
| 1198 | struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
|
| 1199 | size_t length_size;
|
| 1200 | int rc = 0;
|
| 1201 |
|
| 1202 | (*packet_size) = 0;
|
| 1203 | (*new_auth_tok) = NULL;
|
| 1204 | |
| 1205 | * This format is inspired by OpenPGP; see RFC 2440
|
| 1206 | * packet tag 1
|
| 1207 | *
|
| 1208 | * Tag 1 identifier (1 byte)
|
| 1209 | * Max Tag 1 packet size (max 3 bytes)
|
| 1210 | * Version (1 byte)
|
| 1211 | * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
|
| 1212 | * Cipher identifier (1 byte)
|
| 1213 | * Encrypted key size (arbitrary)
|
| 1214 | *
|
| 1215 | * 12 bytes minimum packet size
|
| 1216 |
|
| 1217 | if (unlikely(max_packet_size < 12)) {
|
| 1218 | printk(KERN_ERR "Invalid max packet size; must be >=12\n");
|
| 1219 | rc = -EINVAL;
|
| 1220 | goto out;
|
| 1221 | }
|
| 1222 | if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
|
| 1223 | printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
|
| 1224 | ECRYPTFS_TAG_1_PACKET_TYPE);
|
| 1225 | rc = -EINVAL;
|
| 1226 | goto out;
|
| 1227 | }
|
| 1228 | |
| 1229 | * at end of function upon failure
|
| 1230 | auth_tok_list_item =
|
| 1231 | kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
|
| 1232 | GFP_KERNEL);
|
| 1233 | if (!auth_tok_list_item) {
|
| 1234 | printk(KERN_ERR "Unable to allocate memory\n");
|
| 1235 | rc = -ENOMEM;
|
| 1236 | goto out;
|
| 1237 | }
|
| 1238 | (*new_auth_tok) = &auth_tok_list_item->auth_tok;
|
| 1239 | rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
|
| 1240 | &length_size);
|
| 1241 | if (rc) {
|
| 1242 | printk(KERN_WARNING "Error parsing packet length; "
|
| 1243 | "rc = [%d]\n", rc);
|
| 1244 | goto out_free;
|
| 1245 | }
|
| 1246 | if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
|
| 1247 | printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
|
| 1248 | rc = -EINVAL;
|
| 1249 | goto out_free;
|
| 1250 | }
|
| 1251 | (*packet_size) += length_size;
|
| 1252 | if (unlikely((*packet_size) + body_size > max_packet_size)) {
|
| 1253 | printk(KERN_WARNING "Packet size exceeds max\n");
|
| 1254 | rc = -EINVAL;
|
| 1255 | goto out_free;
|
| 1256 | }
|
| 1257 | if (unlikely(data[(*packet_size)++] != 0x03)) {
|
| 1258 | printk(KERN_WARNING "Unknown version number [%d]\n",
|
| 1259 | data[(*packet_size) - 1]);
|
| 1260 | rc = -EINVAL;
|
| 1261 | goto out_free;
|
| 1262 | }
|
| 1263 | ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
|
| 1264 | &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
|
| 1265 | *packet_size += ECRYPTFS_SIG_SIZE;
|
| 1266 | |
| 1267 | * know which public key encryption algorithm was used
|
| 1268 | (*packet_size)++;
|
| 1269 | (*new_auth_tok)->session_key.encrypted_key_size =
|
| 1270 | body_size - (ECRYPTFS_SIG_SIZE + 2);
|
| 1271 | if ((*new_auth_tok)->session_key.encrypted_key_size
|
| 1272 | > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
|
| 1273 | printk(KERN_WARNING "Tag 1 packet contains key larger "
|
| 1274 | "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
|
| 1275 | rc = -EINVAL;
|
| 1276 | goto out_free;
|
| 1277 | }
|
| 1278 | memcpy((*new_auth_tok)->session_key.encrypted_key,
|
| 1279 | &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
|
| 1280 | (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
|
| 1281 | (*new_auth_tok)->session_key.flags &=
|
| 1282 | ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
|
| 1283 | (*new_auth_tok)->session_key.flags |=
|
| 1284 | ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
|
| 1285 | (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
|
| 1286 | (*new_auth_tok)->flags = 0;
|
| 1287 | (*new_auth_tok)->session_key.flags &=
|
| 1288 | ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
|
| 1289 | (*new_auth_tok)->session_key.flags &=
|
| 1290 | ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
|
| 1291 | list_add(&auth_tok_list_item->list, auth_tok_list);
|
| 1292 | goto out;
|
| 1293 | out_free:
|
| 1294 | (*new_auth_tok) = NULL;
|
| 1295 | memset(auth_tok_list_item, 0,
|
| 1296 | sizeof(struct ecryptfs_auth_tok_list_item));
|
| 1297 | kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
|
| 1298 | auth_tok_list_item);
|
| 1299 | out:
|
| 1300 | if (rc)
|
| 1301 | (*packet_size) = 0;
|
| 1302 | return rc;
|
| 1303 | }
|
| 1304 |
|
| 1305 | |
| 1306 | * parse_tag_3_packet
|
| 1307 | * @crypt_stat: The cryptographic context to modify based on packet
|
| 1308 | * contents.
|
| 1309 | * @data: The raw bytes of the packet.
|
| 1310 | * @auth_tok_list: eCryptfs parses packets into authentication tokens;
|
| 1311 | * a new authentication token will be placed at the end
|
| 1312 | * of this list for this packet.
|
| 1313 | * @new_auth_tok: Pointer to a pointer to memory that this function
|
| 1314 | * allocates; sets the memory address of the pointer to
|
| 1315 | * NULL on error. This object is added to the
|
| 1316 | * auth_tok_list.
|
| 1317 | * @packet_size: This function writes the size of the parsed packet
|
| 1318 | * into this memory location; zero on error.
|
| 1319 | * @max_packet_size: maximum number of bytes to parse
|
| 1320 | *
|
| 1321 | * Returns zero on success; non-zero on error.
|
| 1322 |
|
| 1323 | static int
|
| 1324 | parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
|
| 1325 | unsigned char *data, struct list_head *auth_tok_list,
|
| 1326 | struct ecryptfs_auth_tok **new_auth_tok,
|
| 1327 | size_t *packet_size, size_t max_packet_size)
|
| 1328 | {
|
| 1329 | size_t body_size;
|
| 1330 | struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
|
| 1331 | size_t length_size;
|
| 1332 | int rc = 0;
|
| 1333 |
|
| 1334 | (*packet_size) = 0;
|
| 1335 | (*new_auth_tok) = NULL;
|
| 1336 | |
| 1337 | *This format is inspired by OpenPGP; see RFC 2440
|
| 1338 | * packet tag 3
|
| 1339 | *
|
| 1340 | * Tag 3 identifier (1 byte)
|
| 1341 | * Max Tag 3 packet size (max 3 bytes)
|
| 1342 | * Version (1 byte)
|
| 1343 | * Cipher code (1 byte)
|
| 1344 | * S2K specifier (1 byte)
|
| 1345 | * Hash identifier (1 byte)
|
| 1346 | * Salt (ECRYPTFS_SALT_SIZE)
|
| 1347 | * Hash iterations (1 byte)
|
| 1348 | * Encrypted key (arbitrary)
|
| 1349 | *
|
| 1350 | * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
|
| 1351 |
|
| 1352 | if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
|
| 1353 | printk(KERN_ERR "Max packet size too large\n");
|
| 1354 | rc = -EINVAL;
|
| 1355 | goto out;
|
| 1356 | }
|
| 1357 | if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
|
| 1358 | printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
|
| 1359 | ECRYPTFS_TAG_3_PACKET_TYPE);
|
| 1360 | rc = -EINVAL;
|
| 1361 | goto out;
|
| 1362 | }
|
| 1363 | |
| 1364 | * at end of function upon failure
|
| 1365 | auth_tok_list_item =
|
| 1366 | kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
|
| 1367 | if (!auth_tok_list_item) {
|
| 1368 | printk(KERN_ERR "Unable to allocate memory\n");
|
| 1369 | rc = -ENOMEM;
|
| 1370 | goto out;
|
| 1371 | }
|
| 1372 | (*new_auth_tok) = &auth_tok_list_item->auth_tok;
|
| 1373 | rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
|
| 1374 | &length_size);
|
| 1375 | if (rc) {
|
| 1376 | printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
|
| 1377 | rc);
|
| 1378 | goto out_free;
|
| 1379 | }
|
| 1380 | if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
|
| 1381 | printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
|
| 1382 | rc = -EINVAL;
|
| 1383 | goto out_free;
|
| 1384 | }
|
| 1385 | (*packet_size) += length_size;
|
| 1386 | if (unlikely((*packet_size) + body_size > max_packet_size)) {
|
| 1387 | printk(KERN_ERR "Packet size exceeds max\n");
|
| 1388 | rc = -EINVAL;
|
| 1389 | goto out_free;
|
| 1390 | }
|
| 1391 | (*new_auth_tok)->session_key.encrypted_key_size =
|
| 1392 | (body_size - (ECRYPTFS_SALT_SIZE + 5));
|
| 1393 | |
| 1394 | * Although encrypted_key_size is copied into the
|
| 1395 | * encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES] buffer here,
|
| 1396 | * it later bounds operations on a smaller buffer:
|
| 1397 | * decrypt_passphrase_encrypted_session_key() sets decrypted_key_size =
|
| 1398 | * encrypted_key_size and decrypts into
|
| 1399 | * decrypted_key[ECRYPTFS_MAX_KEY_BYTES], then memcpy's into
|
| 1400 | * crypt_stat->key[ECRYPTFS_MAX_KEY_BYTES]. Limit to
|
| 1401 | * ECRYPTFS_MAX_KEY_BYTES to protect those smaller buffers.
|
| 1402 |
|
| 1403 | if ((*new_auth_tok)->session_key.encrypted_key_size
|
| 1404 | > ECRYPTFS_MAX_KEY_BYTES) {
|
| 1405 | printk(KERN_WARNING "Tag 3 packet contains key larger "
|
| 1406 | "than ECRYPTFS_MAX_KEY_BYTES\n");
|
| 1407 | rc = -EINVAL;
|
| 1408 | goto out_free;
|
| 1409 | }
|
| 1410 | if (unlikely(data[(*packet_size)++] != 0x04)) {
|
| 1411 | printk(KERN_WARNING "Unknown version number [%d]\n",
|
| 1412 | data[(*packet_size) - 1]);
|
| 1413 | rc = -EINVAL;
|
| 1414 | goto out_free;
|
| 1415 | }
|
| 1416 | rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
|
| 1417 | sizeof(crypt_stat->cipher),
|
| 1418 | (u16)data[(*packet_size)]);
|
| 1419 | if (rc)
|
| 1420 | goto out_free;
|
| 1421 | |
| 1422 | * sizes; see RFC2440
|
| 1423 | switch(data[(*packet_size)++]) {
|
| 1424 | case RFC2440_CIPHER_AES_192:
|
| 1425 | crypt_stat->key_size = 24;
|
| 1426 | break;
|
| 1427 | default:
|
| 1428 | crypt_stat->key_size =
|
| 1429 | (*new_auth_tok)->session_key.encrypted_key_size;
|
| 1430 | }
|
| 1431 | rc = ecryptfs_init_crypt_ctx(crypt_stat);
|
| 1432 | if (rc)
|
| 1433 | goto out_free;
|
| 1434 | if (unlikely(data[(*packet_size)++] != 0x03)) {
|
| 1435 | printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
|
| 1436 | rc = -ENOSYS;
|
| 1437 | goto out_free;
|
| 1438 | }
|
| 1439 |
|
| 1440 | switch (data[(*packet_size)++]) {
|
| 1441 | case 0x01:
|
| 1442 |
|
| 1443 | memcpy((*new_auth_tok)->token.password.salt,
|
| 1444 | &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
|
| 1445 | (*packet_size) += ECRYPTFS_SALT_SIZE;
|
| 1446 |
|
| 1447 | (*new_auth_tok)->token.password.hash_iterations =
|
| 1448 | ((u32) 16 + (data[(*packet_size)] & 15))
|
| 1449 | << ((data[(*packet_size)] >> 4) + 6);
|
| 1450 | (*packet_size)++;
|
| 1451 | |
| 1452 | * (*new_auth_tok)->session_key.encrypted_key_size =
|
| 1453 | * (body_size - (ECRYPTFS_SALT_SIZE + 5));
|
| 1454 | memcpy((*new_auth_tok)->session_key.encrypted_key,
|
| 1455 | &data[(*packet_size)],
|
| 1456 | (*new_auth_tok)->session_key.encrypted_key_size);
|
| 1457 | (*packet_size) +=
|
| 1458 | (*new_auth_tok)->session_key.encrypted_key_size;
|
| 1459 | (*new_auth_tok)->session_key.flags &=
|
| 1460 | ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
|
| 1461 | (*new_auth_tok)->session_key.flags |=
|
| 1462 | ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
|
| 1463 | (*new_auth_tok)->token.password.hash_algo = 0x01;
|
| 1464 | break;
|
| 1465 | default:
|
| 1466 | ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
|
| 1467 | "[%d]\n", data[(*packet_size) - 1]);
|
| 1468 | rc = -ENOSYS;
|
| 1469 | goto out_free;
|
| 1470 | }
|
| 1471 | (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
|
| 1472 | |
| 1473 | * decrypt the session key.
|
| 1474 | (*new_auth_tok)->session_key.flags &=
|
| 1475 | ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
|
| 1476 | (*new_auth_tok)->session_key.flags &=
|
| 1477 | ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
|
| 1478 | list_add(&auth_tok_list_item->list, auth_tok_list);
|
| 1479 | goto out;
|
| 1480 | out_free:
|
| 1481 | (*new_auth_tok) = NULL;
|
| 1482 | memset(auth_tok_list_item, 0,
|
| 1483 | sizeof(struct ecryptfs_auth_tok_list_item));
|
| 1484 | kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
|
| 1485 | auth_tok_list_item);
|
| 1486 | out:
|
| 1487 | if (rc)
|
| 1488 | (*packet_size) = 0;
|
| 1489 | return rc;
|
| 1490 | }
|
| 1491 |
|
| 1492 | |
| 1493 | * parse_tag_11_packet
|
| 1494 | * @data: The raw bytes of the packet
|
| 1495 | * @contents: This function writes the data contents of the literal
|
| 1496 | * packet into this memory location
|
| 1497 | * @max_contents_bytes: The maximum number of bytes that this function
|
| 1498 | * is allowed to write into contents
|
| 1499 | * @tag_11_contents_size: This function writes the size of the parsed
|
| 1500 | * contents into this memory location; zero on
|
| 1501 | * error
|
| 1502 | * @packet_size: This function writes the size of the parsed packet
|
| 1503 | * into this memory location; zero on error
|
| 1504 | * @max_packet_size: maximum number of bytes to parse
|
| 1505 | *
|
| 1506 | * Returns zero on success; non-zero on error.
|
| 1507 |
|
| 1508 | static int
|
| 1509 | parse_tag_11_packet(unsigned char *data, unsigned char *contents,
|
| 1510 | size_t max_contents_bytes, size_t *tag_11_contents_size,
|
| 1511 | size_t *packet_size, size_t max_packet_size)
|
| 1512 | {
|
| 1513 | size_t body_size;
|
| 1514 | size_t length_size;
|
| 1515 | int rc = 0;
|
| 1516 |
|
| 1517 | (*packet_size) = 0;
|
| 1518 | (*tag_11_contents_size) = 0;
|
| 1519 | |
| 1520 | * packet tag 11
|
| 1521 | *
|
| 1522 | * Tag 11 identifier (1 byte)
|
| 1523 | * Max Tag 11 packet size (max 3 bytes)
|
| 1524 | * Binary format specifier (1 byte)
|
| 1525 | * Filename length (1 byte)
|
| 1526 | * Filename ("_CONSOLE") (8 bytes)
|
| 1527 | * Modification date (4 bytes)
|
| 1528 | * Literal data (arbitrary)
|
| 1529 | *
|
| 1530 | * We need at least 16 bytes of data for the packet to even be
|
| 1531 | * valid.
|
| 1532 |
|
| 1533 | if (max_packet_size < 16) {
|
| 1534 | printk(KERN_ERR "Maximum packet size too small\n");
|
| 1535 | rc = -EINVAL;
|
| 1536 | goto out;
|
| 1537 | }
|
| 1538 | if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
|
| 1539 | printk(KERN_WARNING "Invalid tag 11 packet format\n");
|
| 1540 | rc = -EINVAL;
|
| 1541 | goto out;
|
| 1542 | }
|
| 1543 | rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
|
| 1544 | &length_size);
|
| 1545 | if (rc) {
|
| 1546 | printk(KERN_WARNING "Invalid tag 11 packet format\n");
|
| 1547 | goto out;
|
| 1548 | }
|
| 1549 | if (body_size < 14) {
|
| 1550 | printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
|
| 1551 | rc = -EINVAL;
|
| 1552 | goto out;
|
| 1553 | }
|
| 1554 | (*packet_size) += length_size;
|
| 1555 | (*tag_11_contents_size) = (body_size - 14);
|
| 1556 | if (unlikely((*packet_size) + body_size > max_packet_size)) {
|
| 1557 | printk(KERN_ERR "Packet size exceeds max\n");
|
| 1558 | rc = -EINVAL;
|
| 1559 | goto out;
|
| 1560 | }
|
| 1561 | if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
|
| 1562 | printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
|
| 1563 | "expected size\n");
|
| 1564 | rc = -EINVAL;
|
| 1565 | goto out;
|
| 1566 | }
|
| 1567 | if (data[(*packet_size)++] != 0x62) {
|
| 1568 | printk(KERN_WARNING "Unrecognizable packet\n");
|
| 1569 | rc = -EINVAL;
|
| 1570 | goto out;
|
| 1571 | }
|
| 1572 | if (data[(*packet_size)++] != 0x08) {
|
| 1573 | printk(KERN_WARNING "Unrecognizable packet\n");
|
| 1574 | rc = -EINVAL;
|
| 1575 | goto out;
|
| 1576 | }
|
| 1577 | (*packet_size) += 12;
|
| 1578 | memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
|
| 1579 | (*packet_size) += (*tag_11_contents_size);
|
| 1580 | out:
|
| 1581 | if (rc) {
|
| 1582 | (*packet_size) = 0;
|
| 1583 | (*tag_11_contents_size) = 0;
|
| 1584 | }
|
| 1585 | return rc;
|
| 1586 | }
|
| 1587 |
|
| 1588 | int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
|
| 1589 | struct ecryptfs_auth_tok **auth_tok,
|
| 1590 | char *sig)
|
| 1591 | {
|
| 1592 | int rc = 0;
|
| 1593 |
|
| 1594 | (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
|
| 1595 | if (IS_ERR(*auth_tok_key)) {
|
| 1596 | (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
|
| 1597 | if (IS_ERR(*auth_tok_key)) {
|
| 1598 | printk(KERN_ERR "Could not find key with description: [%s]\n",
|
| 1599 | sig);
|
| 1600 | rc = process_request_key_err(PTR_ERR(*auth_tok_key));
|
| 1601 | (*auth_tok_key) = NULL;
|
| 1602 | goto out;
|
| 1603 | }
|
| 1604 | }
|
| 1605 | down_write(&(*auth_tok_key)->sem);
|
| 1606 | rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
|
| 1607 | if (rc) {
|
| 1608 | up_write(&(*auth_tok_key)->sem);
|
| 1609 | key_put(*auth_tok_key);
|
| 1610 | (*auth_tok_key) = NULL;
|
| 1611 | goto out;
|
| 1612 | }
|
| 1613 | out:
|
| 1614 | return rc;
|
| 1615 | }
|
| 1616 |
|
| 1617 | |
| 1618 | * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
|
| 1619 | * @auth_tok: The passphrase authentication token to use to encrypt the FEK
|
| 1620 | * @crypt_stat: The cryptographic context
|
| 1621 | *
|
| 1622 | * Returns zero on success; non-zero error otherwise
|
| 1623 |
|
| 1624 | static int
|
| 1625 | decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
|
| 1626 | struct ecryptfs_crypt_stat *crypt_stat)
|
| 1627 | {
|
| 1628 | struct scatterlist dst_sg[2];
|
| 1629 | struct scatterlist src_sg[2];
|
| 1630 | struct mutex *tfm_mutex;
|
| 1631 | struct crypto_skcipher *tfm;
|
| 1632 | struct skcipher_request *req = NULL;
|
| 1633 | int rc = 0;
|
| 1634 |
|
| 1635 | if (unlikely(ecryptfs_verbosity > 0)) {
|
| 1636 | ecryptfs_printk(
|
| 1637 | KERN_DEBUG, "Session key encryption key (size [%d]):\n",
|
| 1638 | auth_tok->token.password.session_key_encryption_key_bytes);
|
| 1639 | ecryptfs_dump_hex(
|
| 1640 | auth_tok->token.password.session_key_encryption_key,
|
| 1641 | auth_tok->token.password.session_key_encryption_key_bytes);
|
| 1642 | }
|
| 1643 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
|
| 1644 | crypt_stat->cipher);
|
| 1645 | if (unlikely(rc)) {
|
| 1646 | printk(KERN_ERR "Internal error whilst attempting to get "
|
| 1647 | "tfm and mutex for cipher name [%s]; rc = [%d]\n",
|
| 1648 | crypt_stat->cipher, rc);
|
| 1649 | goto out;
|
| 1650 | }
|
| 1651 | rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
|
| 1652 | auth_tok->session_key.encrypted_key_size,
|
| 1653 | src_sg, 2);
|
| 1654 | if (rc < 1 || rc > 2) {
|
| 1655 | printk(KERN_ERR "Internal error whilst attempting to convert "
|
| 1656 | "auth_tok->session_key.encrypted_key to scatterlist; "
|
| 1657 | "expected rc = 1; got rc = [%d]. "
|
| 1658 | "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
|
| 1659 | auth_tok->session_key.encrypted_key_size);
|
| 1660 | goto out;
|
| 1661 | }
|
| 1662 | auth_tok->session_key.decrypted_key_size =
|
| 1663 | auth_tok->session_key.encrypted_key_size;
|
| 1664 | rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
|
| 1665 | auth_tok->session_key.decrypted_key_size,
|
| 1666 | dst_sg, 2);
|
| 1667 | if (rc < 1 || rc > 2) {
|
| 1668 | printk(KERN_ERR "Internal error whilst attempting to convert "
|
| 1669 | "auth_tok->session_key.decrypted_key to scatterlist; "
|
| 1670 | "expected rc = 1; got rc = [%d]\n", rc);
|
| 1671 | goto out;
|
| 1672 | }
|
| 1673 | mutex_lock(tfm_mutex);
|
| 1674 | req = skcipher_request_alloc(tfm, GFP_KERNEL);
|
| 1675 | if (!req) {
|
| 1676 | mutex_unlock(tfm_mutex);
|
| 1677 | printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
|
| 1678 | "skcipher_request_alloc for %s\n", __func__,
|
| 1679 | crypto_skcipher_driver_name(tfm));
|
| 1680 | rc = -ENOMEM;
|
| 1681 | goto out;
|
| 1682 | }
|
| 1683 |
|
| 1684 | skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
|
| 1685 | NULL, NULL);
|
| 1686 | rc = crypto_skcipher_setkey(
|
| 1687 | tfm, auth_tok->token.password.session_key_encryption_key,
|
| 1688 | crypt_stat->key_size);
|
| 1689 | if (unlikely(rc < 0)) {
|
| 1690 | mutex_unlock(tfm_mutex);
|
| 1691 | printk(KERN_ERR "Error setting key for crypto context\n");
|
| 1692 | rc = -EINVAL;
|
| 1693 | goto out;
|
| 1694 | }
|
| 1695 | skcipher_request_set_crypt(req, src_sg, dst_sg,
|
| 1696 | auth_tok->session_key.encrypted_key_size,
|
| 1697 | NULL);
|
| 1698 | rc = crypto_skcipher_decrypt(req);
|
| 1699 | mutex_unlock(tfm_mutex);
|
| 1700 | if (unlikely(rc)) {
|
| 1701 | printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
|
| 1702 | goto out;
|
| 1703 | }
|
| 1704 | auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
|
| 1705 | memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
|
| 1706 | auth_tok->session_key.decrypted_key_size);
|
| 1707 | crypt_stat->flags |= ECRYPTFS_KEY_VALID;
|
| 1708 | if (unlikely(ecryptfs_verbosity > 0)) {
|
| 1709 | ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
|
| 1710 | crypt_stat->key_size);
|
| 1711 | ecryptfs_dump_hex(crypt_stat->key,
|
| 1712 | crypt_stat->key_size);
|
| 1713 | }
|
| 1714 | out:
|
| 1715 | skcipher_request_free(req);
|
| 1716 | return rc;
|
| 1717 | }
|
| 1718 |
|
| 1719 | |
| 1720 | * ecryptfs_parse_packet_set
|
| 1721 | * @crypt_stat: The cryptographic context
|
| 1722 | * @src: Virtual address of region of memory containing the packets
|
| 1723 | * @src_size: Size of the packet set buffer
|
| 1724 | * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
|
| 1725 | *
|
| 1726 | * Get crypt_stat to have the file's session key if the requisite key
|
| 1727 | * is available to decrypt the session key.
|
| 1728 | *
|
| 1729 | * Returns Zero if a valid authentication token was retrieved and
|
| 1730 | * processed; negative value for file not encrypted or for error
|
| 1731 | * conditions.
|
| 1732 |
|
| 1733 | int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
|
| 1734 | unsigned char *src, size_t src_size,
|
| 1735 | struct dentry *ecryptfs_dentry)
|
| 1736 | {
|
| 1737 | size_t i = 0;
|
| 1738 | size_t next_packet_is_auth_tok_packet;
|
| 1739 | LIST_HEAD(auth_tok_list);
|
| 1740 | struct ecryptfs_auth_tok *matching_auth_tok;
|
| 1741 | struct ecryptfs_auth_tok *candidate_auth_tok;
|
| 1742 | char *candidate_auth_tok_sig;
|
| 1743 | size_t packet_size;
|
| 1744 | struct ecryptfs_auth_tok *new_auth_tok;
|
| 1745 | unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
|
| 1746 | struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
|
| 1747 | size_t tag_11_contents_size;
|
| 1748 | size_t tag_11_packet_size;
|
| 1749 | struct key *auth_tok_key = NULL;
|
| 1750 | int rc = 0;
|
| 1751 |
|
| 1752 | |
| 1753 | * added the our &auth_tok_list
|
| 1754 | next_packet_is_auth_tok_packet = 1;
|
| 1755 | while (next_packet_is_auth_tok_packet) {
|
| 1756 | size_t max_packet_size;
|
| 1757 |
|
| 1758 | if (i >= src_size)
|
| 1759 | break;
|
| 1760 | max_packet_size = src_size - i;
|
| 1761 |
|
| 1762 | switch (src[i]) {
|
| 1763 | case ECRYPTFS_TAG_3_PACKET_TYPE:
|
| 1764 | rc = parse_tag_3_packet(crypt_stat,
|
| 1765 | (unsigned char *)&src[i],
|
| 1766 | &auth_tok_list, &new_auth_tok,
|
| 1767 | &packet_size, max_packet_size);
|
| 1768 | if (rc) {
|
| 1769 | ecryptfs_printk(KERN_ERR, "Error parsing "
|
| 1770 | "tag 3 packet\n");
|
| 1771 | rc = -EIO;
|
| 1772 | goto out_wipe_list;
|
| 1773 | }
|
| 1774 | i += packet_size;
|
| 1775 | if (i > src_size) {
|
| 1776 | rc = -EIO;
|
| 1777 | goto out_wipe_list;
|
| 1778 | }
|
| 1779 | rc = parse_tag_11_packet((unsigned char *)&src[i],
|
| 1780 | sig_tmp_space,
|
| 1781 | ECRYPTFS_SIG_SIZE,
|
| 1782 | &tag_11_contents_size,
|
| 1783 | &tag_11_packet_size,
|
| 1784 | src_size - i);
|
| 1785 | if (rc) {
|
| 1786 | ecryptfs_printk(KERN_ERR, "No valid "
|
| 1787 | "(ecryptfs-specific) literal "
|
| 1788 | "packet containing "
|
| 1789 | "authentication token "
|
| 1790 | "signature found after "
|
| 1791 | "tag 3 packet\n");
|
| 1792 | rc = -EIO;
|
| 1793 | goto out_wipe_list;
|
| 1794 | }
|
| 1795 | i += tag_11_packet_size;
|
| 1796 | if (i > src_size) {
|
| 1797 | rc = -EIO;
|
| 1798 | goto out_wipe_list;
|
| 1799 | }
|
| 1800 | if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
|
| 1801 | ecryptfs_printk(KERN_ERR, "Expected "
|
| 1802 | "signature of size [%d]; "
|
| 1803 | "read size [%zd]\n",
|
| 1804 | ECRYPTFS_SIG_SIZE,
|
| 1805 | tag_11_contents_size);
|
| 1806 | rc = -EIO;
|
| 1807 | goto out_wipe_list;
|
| 1808 | }
|
| 1809 | ecryptfs_to_hex(new_auth_tok->token.password.signature,
|
| 1810 | sig_tmp_space, tag_11_contents_size);
|
| 1811 | crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
|
| 1812 | break;
|
| 1813 | case ECRYPTFS_TAG_1_PACKET_TYPE:
|
| 1814 | rc = parse_tag_1_packet(crypt_stat,
|
| 1815 | (unsigned char *)&src[i],
|
| 1816 | &auth_tok_list, &new_auth_tok,
|
| 1817 | &packet_size, max_packet_size);
|
| 1818 | if (rc) {
|
| 1819 | ecryptfs_printk(KERN_ERR, "Error parsing "
|
| 1820 | "tag 1 packet\n");
|
| 1821 | rc = -EIO;
|
| 1822 | goto out_wipe_list;
|
| 1823 | }
|
| 1824 | i += packet_size;
|
| 1825 | if (i > src_size) {
|
| 1826 | rc = -EIO;
|
| 1827 | goto out_wipe_list;
|
| 1828 | }
|
| 1829 | crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
|
| 1830 | break;
|
| 1831 | case ECRYPTFS_TAG_11_PACKET_TYPE:
|
| 1832 | ecryptfs_printk(KERN_WARNING, "Invalid packet set "
|
| 1833 | "(Tag 11 not allowed by itself)\n");
|
| 1834 | rc = -EIO;
|
| 1835 | goto out_wipe_list;
|
| 1836 | default:
|
| 1837 | ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
|
| 1838 | "of the file header; hex value of "
|
| 1839 | "character is [0x%.2x]\n", i, src[i]);
|
| 1840 | next_packet_is_auth_tok_packet = 0;
|
| 1841 | }
|
| 1842 | }
|
| 1843 | if (list_empty(&auth_tok_list)) {
|
| 1844 | printk(KERN_ERR "The lower file appears to be a non-encrypted "
|
| 1845 | "eCryptfs file; this is not supported in this version "
|
| 1846 | "of the eCryptfs kernel module\n");
|
| 1847 | rc = -EINVAL;
|
| 1848 | goto out;
|
| 1849 | }
|
| 1850 | |
| 1851 | * parsed from the metadata. We need to find a matching
|
| 1852 | * authentication token that has the secret component(s)
|
| 1853 | * necessary to decrypt the EFEK in the auth_tok parsed from
|
| 1854 | * the metadata. There may be several potential matches, but
|
| 1855 | * just one will be sufficient to decrypt to get the FEK.
|
| 1856 | find_next_matching_auth_tok:
|
| 1857 | list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
|
| 1858 | candidate_auth_tok = &auth_tok_list_item->auth_tok;
|
| 1859 | if (unlikely(ecryptfs_verbosity > 0)) {
|
| 1860 | ecryptfs_printk(KERN_DEBUG,
|
| 1861 | "Considering candidate auth tok:\n");
|
| 1862 | ecryptfs_dump_auth_tok(candidate_auth_tok);
|
| 1863 | }
|
| 1864 | rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
|
| 1865 | candidate_auth_tok);
|
| 1866 | if (rc) {
|
| 1867 | printk(KERN_ERR
|
| 1868 | "Unrecognized candidate auth tok type: [%d]\n",
|
| 1869 | candidate_auth_tok->token_type);
|
| 1870 | rc = -EINVAL;
|
| 1871 | goto out_wipe_list;
|
| 1872 | }
|
| 1873 | rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
|
| 1874 | &matching_auth_tok,
|
| 1875 | crypt_stat->mount_crypt_stat,
|
| 1876 | candidate_auth_tok_sig);
|
| 1877 | if (!rc)
|
| 1878 | goto found_matching_auth_tok;
|
| 1879 | }
|
| 1880 | ecryptfs_printk(KERN_ERR,
|
| 1881 | "Could not find a usable authentication token\n");
|
| 1882 | rc = -EIO;
|
| 1883 | goto out_wipe_list;
|
| 1884 | found_matching_auth_tok:
|
| 1885 | if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
|
| 1886 | memcpy(&(candidate_auth_tok->token.private_key),
|
| 1887 | &(matching_auth_tok->token.private_key),
|
| 1888 | sizeof(struct ecryptfs_private_key));
|
| 1889 | up_write(&(auth_tok_key->sem));
|
| 1890 | key_put(auth_tok_key);
|
| 1891 | rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
|
| 1892 | crypt_stat);
|
| 1893 | } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
|
| 1894 | memcpy(&(candidate_auth_tok->token.password),
|
| 1895 | &(matching_auth_tok->token.password),
|
| 1896 | sizeof(struct ecryptfs_password));
|
| 1897 | up_write(&(auth_tok_key->sem));
|
| 1898 | key_put(auth_tok_key);
|
| 1899 | rc = decrypt_passphrase_encrypted_session_key(
|
| 1900 | candidate_auth_tok, crypt_stat);
|
| 1901 | } else {
|
| 1902 | up_write(&(auth_tok_key->sem));
|
| 1903 | key_put(auth_tok_key);
|
| 1904 | rc = -EINVAL;
|
| 1905 | }
|
| 1906 | if (rc) {
|
| 1907 | struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
|
| 1908 |
|
| 1909 | ecryptfs_printk(KERN_WARNING, "Error decrypting the "
|
| 1910 | "session key for authentication token with sig "
|
| 1911 | "[%.*s]; rc = [%d]. Removing auth tok "
|
| 1912 | "candidate from the list and searching for "
|
| 1913 | "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
|
| 1914 | candidate_auth_tok_sig, rc);
|
| 1915 | list_for_each_entry_safe(auth_tok_list_item,
|
| 1916 | auth_tok_list_item_tmp,
|
| 1917 | &auth_tok_list, list) {
|
| 1918 | if (candidate_auth_tok
|
| 1919 | == &auth_tok_list_item->auth_tok) {
|
| 1920 | list_del(&auth_tok_list_item->list);
|
| 1921 | kmem_cache_free(
|
| 1922 | ecryptfs_auth_tok_list_item_cache,
|
| 1923 | auth_tok_list_item);
|
| 1924 | goto find_next_matching_auth_tok;
|
| 1925 | }
|
| 1926 | }
|
| 1927 | BUG();
|
| 1928 | }
|
| 1929 | rc = ecryptfs_compute_root_iv(crypt_stat);
|
| 1930 | if (rc) {
|
| 1931 | ecryptfs_printk(KERN_ERR, "Error computing "
|
| 1932 | "the root IV\n");
|
| 1933 | goto out_wipe_list;
|
| 1934 | }
|
| 1935 | rc = ecryptfs_init_crypt_ctx(crypt_stat);
|
| 1936 | if (rc) {
|
| 1937 | ecryptfs_printk(KERN_ERR, "Error initializing crypto "
|
| 1938 | "context for cipher [%s]; rc = [%d]\n",
|
| 1939 | crypt_stat->cipher, rc);
|
| 1940 | }
|
| 1941 | out_wipe_list:
|
| 1942 | wipe_auth_tok_list(&auth_tok_list);
|
| 1943 | out:
|
| 1944 | return rc;
|
| 1945 | }
|
| 1946 |
|
| 1947 | static int
|
| 1948 | pki_encrypt_session_key(struct key *auth_tok_key,
|
| 1949 | struct ecryptfs_auth_tok *auth_tok,
|
| 1950 | struct ecryptfs_crypt_stat *crypt_stat,
|
| 1951 | struct ecryptfs_key_record *key_rec)
|
| 1952 | {
|
| 1953 | struct ecryptfs_msg_ctx *msg_ctx = NULL;
|
| 1954 | char *payload = NULL;
|
| 1955 | size_t payload_len = 0;
|
| 1956 | struct ecryptfs_message *msg;
|
| 1957 | int rc;
|
| 1958 |
|
| 1959 | rc = write_tag_66_packet(auth_tok->token.private_key.signature,
|
| 1960 | ecryptfs_code_for_cipher_string(
|
| 1961 | crypt_stat->cipher,
|
| 1962 | crypt_stat->key_size),
|
| 1963 | crypt_stat, &payload, &payload_len);
|
| 1964 | up_write(&(auth_tok_key->sem));
|
| 1965 | key_put(auth_tok_key);
|
| 1966 | if (rc) {
|
| 1967 | ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
|
| 1968 | goto out;
|
| 1969 | }
|
| 1970 | rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
|
| 1971 | if (rc) {
|
| 1972 | ecryptfs_printk(KERN_ERR, "Error sending message to "
|
| 1973 | "ecryptfsd: %d\n", rc);
|
| 1974 | goto out;
|
| 1975 | }
|
| 1976 | rc = ecryptfs_wait_for_response(msg_ctx, &msg);
|
| 1977 | if (rc) {
|
| 1978 | ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
|
| 1979 | "from the user space daemon\n");
|
| 1980 | rc = -EIO;
|
| 1981 | goto out;
|
| 1982 | }
|
| 1983 | rc = parse_tag_67_packet(key_rec, msg);
|
| 1984 | if (rc)
|
| 1985 | ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
|
| 1986 | kfree(msg);
|
| 1987 | out:
|
| 1988 | kfree(payload);
|
| 1989 | return rc;
|
| 1990 | }
|
| 1991 | |
| 1992 | * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
|
| 1993 | * @dest: Buffer into which to write the packet
|
| 1994 | * @remaining_bytes: Maximum number of bytes that can be writtn
|
| 1995 | * @auth_tok_key: The authentication token key to unlock and put when done with
|
| 1996 | * @auth_tok
|
| 1997 | * @auth_tok: The authentication token used for generating the tag 1 packet
|
| 1998 | * @crypt_stat: The cryptographic context
|
| 1999 | * @key_rec: The key record struct for the tag 1 packet
|
| 2000 | * @packet_size: This function will write the number of bytes that end
|
| 2001 | * up constituting the packet; set to zero on error
|
| 2002 | *
|
| 2003 | * Returns zero on success; non-zero on error.
|
| 2004 |
|
| 2005 | static int
|
| 2006 | write_tag_1_packet(char *dest, size_t *remaining_bytes,
|
| 2007 | struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
|
| 2008 | struct ecryptfs_crypt_stat *crypt_stat,
|
| 2009 | struct ecryptfs_key_record *key_rec, size_t *packet_size)
|
| 2010 | {
|
| 2011 | size_t i;
|
| 2012 | size_t encrypted_session_key_valid = 0;
|
| 2013 | size_t packet_size_length;
|
| 2014 | size_t max_packet_size;
|
| 2015 | int rc = 0;
|
| 2016 |
|
| 2017 | (*packet_size) = 0;
|
| 2018 | ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
|
| 2019 | ECRYPTFS_SIG_SIZE);
|
| 2020 | encrypted_session_key_valid = 0;
|
| 2021 | for (i = 0; i < crypt_stat->key_size; i++)
|
| 2022 | encrypted_session_key_valid |=
|
| 2023 | auth_tok->session_key.encrypted_key[i];
|
| 2024 | if (encrypted_session_key_valid) {
|
| 2025 | memcpy(key_rec->enc_key,
|
| 2026 | auth_tok->session_key.encrypted_key,
|
| 2027 | auth_tok->session_key.encrypted_key_size);
|
| 2028 | up_write(&(auth_tok_key->sem));
|
| 2029 | key_put(auth_tok_key);
|
| 2030 | goto encrypted_session_key_set;
|
| 2031 | }
|
| 2032 | if (auth_tok->session_key.encrypted_key_size == 0)
|
| 2033 | auth_tok->session_key.encrypted_key_size =
|
| 2034 | auth_tok->token.private_key.key_size;
|
| 2035 | rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
|
| 2036 | key_rec);
|
| 2037 | if (rc) {
|
| 2038 | printk(KERN_ERR "Failed to encrypt session key via a key "
|
| 2039 | "module; rc = [%d]\n", rc);
|
| 2040 | goto out;
|
| 2041 | }
|
| 2042 | if (ecryptfs_verbosity > 0) {
|
| 2043 | ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
|
| 2044 | ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
|
| 2045 | }
|
| 2046 | encrypted_session_key_set:
|
| 2047 | |
| 2048 | * packet tag 1
|
| 2049 | max_packet_size = (1
|
| 2050 | + 3
|
| 2051 | + 1
|
| 2052 | + ECRYPTFS_SIG_SIZE
|
| 2053 | + 1
|
| 2054 | + key_rec->enc_key_size);
|
| 2055 | if (max_packet_size > (*remaining_bytes)) {
|
| 2056 | printk(KERN_ERR "Packet length larger than maximum allowable; "
|
| 2057 | "need up to [%td] bytes, but there are only [%td] "
|
| 2058 | "available\n", max_packet_size, (*remaining_bytes));
|
| 2059 | rc = -EINVAL;
|
| 2060 | goto out;
|
| 2061 | }
|
| 2062 | dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
|
| 2063 | rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
|
| 2064 | (max_packet_size - 4),
|
| 2065 | &packet_size_length);
|
| 2066 | if (rc) {
|
| 2067 | ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
|
| 2068 | "header; cannot generate packet length\n");
|
| 2069 | goto out;
|
| 2070 | }
|
| 2071 | (*packet_size) += packet_size_length;
|
| 2072 | dest[(*packet_size)++] = 0x03;
|
| 2073 | memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
|
| 2074 | (*packet_size) += ECRYPTFS_SIG_SIZE;
|
| 2075 | dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
|
| 2076 | memcpy(&dest[(*packet_size)], key_rec->enc_key,
|
| 2077 | key_rec->enc_key_size);
|
| 2078 | (*packet_size) += key_rec->enc_key_size;
|
| 2079 | out:
|
| 2080 | if (rc)
|
| 2081 | (*packet_size) = 0;
|
| 2082 | else
|
| 2083 | (*remaining_bytes) -= (*packet_size);
|
| 2084 | return rc;
|
| 2085 | }
|
| 2086 |
|
| 2087 | |
| 2088 | * write_tag_11_packet
|
| 2089 | * @dest: Target into which Tag 11 packet is to be written
|
| 2090 | * @remaining_bytes: Maximum packet length
|
| 2091 | * @contents: Byte array of contents to copy in
|
| 2092 | * @contents_length: Number of bytes in contents
|
| 2093 | * @packet_length: Length of the Tag 11 packet written; zero on error
|
| 2094 | *
|
| 2095 | * Returns zero on success; non-zero on error.
|
| 2096 |
|
| 2097 | static int
|
| 2098 | write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
|
| 2099 | size_t contents_length, size_t *packet_length)
|
| 2100 | {
|
| 2101 | size_t packet_size_length;
|
| 2102 | size_t max_packet_size;
|
| 2103 | int rc = 0;
|
| 2104 |
|
| 2105 | (*packet_length) = 0;
|
| 2106 | |
| 2107 | * packet tag 11
|
| 2108 | max_packet_size = (1
|
| 2109 | + 3
|
| 2110 | + 1
|
| 2111 | + 1
|
| 2112 | + 8
|
| 2113 | + 4
|
| 2114 | + contents_length);
|
| 2115 | if (max_packet_size > (*remaining_bytes)) {
|
| 2116 | printk(KERN_ERR "Packet length larger than maximum allowable; "
|
| 2117 | "need up to [%td] bytes, but there are only [%td] "
|
| 2118 | "available\n", max_packet_size, (*remaining_bytes));
|
| 2119 | rc = -EINVAL;
|
| 2120 | goto out;
|
| 2121 | }
|
| 2122 | dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
|
| 2123 | rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
|
| 2124 | (max_packet_size - 4),
|
| 2125 | &packet_size_length);
|
| 2126 | if (rc) {
|
| 2127 | printk(KERN_ERR "Error generating tag 11 packet header; cannot "
|
| 2128 | "generate packet length. rc = [%d]\n", rc);
|
| 2129 | goto out;
|
| 2130 | }
|
| 2131 | (*packet_length) += packet_size_length;
|
| 2132 | dest[(*packet_length)++] = 0x62;
|
| 2133 | dest[(*packet_length)++] = 8;
|
| 2134 | memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
|
| 2135 | (*packet_length) += 8;
|
| 2136 | memset(&dest[(*packet_length)], 0x00, 4);
|
| 2137 | (*packet_length) += 4;
|
| 2138 | memcpy(&dest[(*packet_length)], contents, contents_length);
|
| 2139 | (*packet_length) += contents_length;
|
| 2140 | out:
|
| 2141 | if (rc)
|
| 2142 | (*packet_length) = 0;
|
| 2143 | else
|
| 2144 | (*remaining_bytes) -= (*packet_length);
|
| 2145 | return rc;
|
| 2146 | }
|
| 2147 |
|
| 2148 | |
| 2149 | * write_tag_3_packet
|
| 2150 | * @dest: Buffer into which to write the packet
|
| 2151 | * @remaining_bytes: Maximum number of bytes that can be written
|
| 2152 | * @auth_tok: Authentication token
|
| 2153 | * @crypt_stat: The cryptographic context
|
| 2154 | * @key_rec: encrypted key
|
| 2155 | * @packet_size: This function will write the number of bytes that end
|
| 2156 | * up constituting the packet; set to zero on error
|
| 2157 | *
|
| 2158 | * Returns zero on success; non-zero on error.
|
| 2159 |
|
| 2160 | static int
|
| 2161 | write_tag_3_packet(char *dest, size_t *remaining_bytes,
|
| 2162 | struct ecryptfs_auth_tok *auth_tok,
|
| 2163 | struct ecryptfs_crypt_stat *crypt_stat,
|
| 2164 | struct ecryptfs_key_record *key_rec, size_t *packet_size)
|
| 2165 | {
|
| 2166 | size_t i;
|
| 2167 | size_t encrypted_session_key_valid = 0;
|
| 2168 | char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
|
| 2169 | struct scatterlist dst_sg[2];
|
| 2170 | struct scatterlist src_sg[2];
|
| 2171 | struct mutex *tfm_mutex = NULL;
|
| 2172 | u8 cipher_code;
|
| 2173 | size_t packet_size_length;
|
| 2174 | size_t max_packet_size;
|
| 2175 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
|
| 2176 | crypt_stat->mount_crypt_stat;
|
| 2177 | struct crypto_skcipher *tfm;
|
| 2178 | struct skcipher_request *req;
|
| 2179 | int rc = 0;
|
| 2180 |
|
| 2181 | (*packet_size) = 0;
|
| 2182 | ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
|
| 2183 | ECRYPTFS_SIG_SIZE);
|
| 2184 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
|
| 2185 | crypt_stat->cipher);
|
| 2186 | if (unlikely(rc)) {
|
| 2187 | printk(KERN_ERR "Internal error whilst attempting to get "
|
| 2188 | "tfm and mutex for cipher name [%s]; rc = [%d]\n",
|
| 2189 | crypt_stat->cipher, rc);
|
| 2190 | goto out;
|
| 2191 | }
|
| 2192 | if (mount_crypt_stat->global_default_cipher_key_size == 0) {
|
| 2193 | printk(KERN_WARNING "No key size specified at mount; "
|
| 2194 | "defaulting to [%d]\n",
|
| 2195 | crypto_skcipher_max_keysize(tfm));
|
| 2196 | mount_crypt_stat->global_default_cipher_key_size =
|
| 2197 | crypto_skcipher_max_keysize(tfm);
|
| 2198 | }
|
| 2199 | if (crypt_stat->key_size == 0)
|
| 2200 | crypt_stat->key_size =
|
| 2201 | mount_crypt_stat->global_default_cipher_key_size;
|
| 2202 | if (auth_tok->session_key.encrypted_key_size == 0)
|
| 2203 | auth_tok->session_key.encrypted_key_size =
|
| 2204 | crypt_stat->key_size;
|
| 2205 | if (crypt_stat->key_size == 24
|
| 2206 | && strcmp("aes", crypt_stat->cipher) == 0) {
|
| 2207 | memset((crypt_stat->key + 24), 0, 8);
|
| 2208 | auth_tok->session_key.encrypted_key_size = 32;
|
| 2209 | } else
|
| 2210 | auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
|
| 2211 | key_rec->enc_key_size =
|
| 2212 | auth_tok->session_key.encrypted_key_size;
|
| 2213 | encrypted_session_key_valid = 0;
|
| 2214 | for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
|
| 2215 | encrypted_session_key_valid |=
|
| 2216 | auth_tok->session_key.encrypted_key[i];
|
| 2217 | if (encrypted_session_key_valid) {
|
| 2218 | ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
|
| 2219 | "using auth_tok->session_key.encrypted_key, "
|
| 2220 | "where key_rec->enc_key_size = [%zd]\n",
|
| 2221 | key_rec->enc_key_size);
|
| 2222 | memcpy(key_rec->enc_key,
|
| 2223 | auth_tok->session_key.encrypted_key,
|
| 2224 | key_rec->enc_key_size);
|
| 2225 | goto encrypted_session_key_set;
|
| 2226 | }
|
| 2227 | if (auth_tok->token.password.flags &
|
| 2228 | ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
|
| 2229 | ecryptfs_printk(KERN_DEBUG, "Using previously generated "
|
| 2230 | "session key encryption key of size [%d]\n",
|
| 2231 | auth_tok->token.password.
|
| 2232 | session_key_encryption_key_bytes);
|
| 2233 | memcpy(session_key_encryption_key,
|
| 2234 | auth_tok->token.password.session_key_encryption_key,
|
| 2235 | crypt_stat->key_size);
|
| 2236 | ecryptfs_printk(KERN_DEBUG,
|
| 2237 | "Cached session key encryption key:\n");
|
| 2238 | if (ecryptfs_verbosity > 0)
|
| 2239 | ecryptfs_dump_hex(session_key_encryption_key, 16);
|
| 2240 | }
|
| 2241 | if (unlikely(ecryptfs_verbosity > 0)) {
|
| 2242 | ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
|
| 2243 | ecryptfs_dump_hex(session_key_encryption_key, 16);
|
| 2244 | }
|
| 2245 | rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
|
| 2246 | src_sg, 2);
|
| 2247 | if (rc < 1 || rc > 2) {
|
| 2248 | ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
|
| 2249 | "for crypt_stat session key; expected rc = 1; "
|
| 2250 | "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
|
| 2251 | rc, key_rec->enc_key_size);
|
| 2252 | rc = -ENOMEM;
|
| 2253 | goto out;
|
| 2254 | }
|
| 2255 | rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
|
| 2256 | dst_sg, 2);
|
| 2257 | if (rc < 1 || rc > 2) {
|
| 2258 | ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
|
| 2259 | "for crypt_stat encrypted session key; "
|
| 2260 | "expected rc = 1; got rc = [%d]. "
|
| 2261 | "key_rec->enc_key_size = [%zd]\n", rc,
|
| 2262 | key_rec->enc_key_size);
|
| 2263 | rc = -ENOMEM;
|
| 2264 | goto out;
|
| 2265 | }
|
| 2266 | mutex_lock(tfm_mutex);
|
| 2267 | rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
|
| 2268 | crypt_stat->key_size);
|
| 2269 | if (rc < 0) {
|
| 2270 | mutex_unlock(tfm_mutex);
|
| 2271 | ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
|
| 2272 | "context; rc = [%d]\n", rc);
|
| 2273 | goto out;
|
| 2274 | }
|
| 2275 |
|
| 2276 | req = skcipher_request_alloc(tfm, GFP_KERNEL);
|
| 2277 | if (!req) {
|
| 2278 | mutex_unlock(tfm_mutex);
|
| 2279 | ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
|
| 2280 | "attempting to skcipher_request_alloc for "
|
| 2281 | "%s\n", crypto_skcipher_driver_name(tfm));
|
| 2282 | rc = -ENOMEM;
|
| 2283 | goto out;
|
| 2284 | }
|
| 2285 |
|
| 2286 | skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
|
| 2287 | NULL, NULL);
|
| 2288 |
|
| 2289 | rc = 0;
|
| 2290 | ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
|
| 2291 | crypt_stat->key_size);
|
| 2292 | skcipher_request_set_crypt(req, src_sg, dst_sg,
|
| 2293 | (*key_rec).enc_key_size, NULL);
|
| 2294 | rc = crypto_skcipher_encrypt(req);
|
| 2295 | mutex_unlock(tfm_mutex);
|
| 2296 | skcipher_request_free(req);
|
| 2297 | if (rc) {
|
| 2298 | printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
|
| 2299 | goto out;
|
| 2300 | }
|
| 2301 | ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
|
| 2302 | if (ecryptfs_verbosity > 0) {
|
| 2303 | ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
|
| 2304 | key_rec->enc_key_size);
|
| 2305 | ecryptfs_dump_hex(key_rec->enc_key,
|
| 2306 | key_rec->enc_key_size);
|
| 2307 | }
|
| 2308 | encrypted_session_key_set:
|
| 2309 | |
| 2310 | * packet tag 3
|
| 2311 | max_packet_size = (1
|
| 2312 | + 3
|
| 2313 | + 1
|
| 2314 | + 1
|
| 2315 | + 1
|
| 2316 | + 1
|
| 2317 | + ECRYPTFS_SALT_SIZE
|
| 2318 | + 1
|
| 2319 | + key_rec->enc_key_size);
|
| 2320 | if (max_packet_size > (*remaining_bytes)) {
|
| 2321 | printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
|
| 2322 | "there are only [%td] available\n", max_packet_size,
|
| 2323 | (*remaining_bytes));
|
| 2324 | rc = -EINVAL;
|
| 2325 | goto out;
|
| 2326 | }
|
| 2327 | dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
|
| 2328 | |
| 2329 | * to get the number of octets in the actual Tag 3 packet
|
| 2330 | rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
|
| 2331 | (max_packet_size - 4),
|
| 2332 | &packet_size_length);
|
| 2333 | if (rc) {
|
| 2334 | printk(KERN_ERR "Error generating tag 3 packet header; cannot "
|
| 2335 | "generate packet length. rc = [%d]\n", rc);
|
| 2336 | goto out;
|
| 2337 | }
|
| 2338 | (*packet_size) += packet_size_length;
|
| 2339 | dest[(*packet_size)++] = 0x04;
|
| 2340 | |
| 2341 | * specified with strings
|
| 2342 | cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
|
| 2343 | crypt_stat->key_size);
|
| 2344 | if (cipher_code == 0) {
|
| 2345 | ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
|
| 2346 | "cipher [%s]\n", crypt_stat->cipher);
|
| 2347 | rc = -EINVAL;
|
| 2348 | goto out;
|
| 2349 | }
|
| 2350 | dest[(*packet_size)++] = cipher_code;
|
| 2351 | dest[(*packet_size)++] = 0x03;
|
| 2352 | dest[(*packet_size)++] = 0x01;
|
| 2353 | memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
|
| 2354 | ECRYPTFS_SALT_SIZE);
|
| 2355 | (*packet_size) += ECRYPTFS_SALT_SIZE;
|
| 2356 | dest[(*packet_size)++] = 0x60;
|
| 2357 | memcpy(&dest[(*packet_size)], key_rec->enc_key,
|
| 2358 | key_rec->enc_key_size);
|
| 2359 | (*packet_size) += key_rec->enc_key_size;
|
| 2360 | out:
|
| 2361 | if (rc)
|
| 2362 | (*packet_size) = 0;
|
| 2363 | else
|
| 2364 | (*remaining_bytes) -= (*packet_size);
|
| 2365 | return rc;
|
| 2366 | }
|
| 2367 |
|
| 2368 | struct kmem_cache *ecryptfs_key_record_cache;
|
| 2369 |
|
| 2370 | |
| 2371 | * ecryptfs_generate_key_packet_set
|
| 2372 | * @dest_base: Virtual address from which to write the key record set
|
| 2373 | * @crypt_stat: The cryptographic context from which the
|
| 2374 | * authentication tokens will be retrieved
|
| 2375 | * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
|
| 2376 | * for the global parameters
|
| 2377 | * @len: The amount written
|
| 2378 | * @max: The maximum amount of data allowed to be written
|
| 2379 | *
|
| 2380 | * Generates a key packet set and writes it to the virtual address
|
| 2381 | * passed in.
|
| 2382 | *
|
| 2383 | * Returns zero on success; non-zero on error.
|
| 2384 |
|
| 2385 | int
|
| 2386 | ecryptfs_generate_key_packet_set(char *dest_base,
|
| 2387 | struct ecryptfs_crypt_stat *crypt_stat,
|
| 2388 | struct dentry *ecryptfs_dentry, size_t *len,
|
| 2389 | size_t max)
|
| 2390 | {
|
| 2391 | struct ecryptfs_auth_tok *auth_tok;
|
| 2392 | struct key *auth_tok_key = NULL;
|
| 2393 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
|
| 2394 | &ecryptfs_superblock_to_private(
|
| 2395 | ecryptfs_dentry->d_sb)->mount_crypt_stat;
|
| 2396 | size_t written;
|
| 2397 | struct ecryptfs_key_record *key_rec;
|
| 2398 | struct ecryptfs_key_sig *key_sig;
|
| 2399 | int rc = 0;
|
| 2400 |
|
| 2401 | (*len) = 0;
|
| 2402 | mutex_lock(&crypt_stat->keysig_list_mutex);
|
| 2403 | key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
|
| 2404 | if (!key_rec) {
|
| 2405 | rc = -ENOMEM;
|
| 2406 | goto out;
|
| 2407 | }
|
| 2408 | list_for_each_entry(key_sig, &crypt_stat->keysig_list,
|
| 2409 | crypt_stat_list) {
|
| 2410 | memset(key_rec, 0, sizeof(*key_rec));
|
| 2411 | rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
|
| 2412 | &auth_tok,
|
| 2413 | mount_crypt_stat,
|
| 2414 | key_sig->keysig);
|
| 2415 | if (rc) {
|
| 2416 | printk(KERN_WARNING "Unable to retrieve auth tok with "
|
| 2417 | "sig = [%s]\n", key_sig->keysig);
|
| 2418 | rc = process_find_global_auth_tok_for_sig_err(rc);
|
| 2419 | goto out_free;
|
| 2420 | }
|
| 2421 | if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
|
| 2422 | rc = write_tag_3_packet((dest_base + (*len)),
|
| 2423 | &max, auth_tok,
|
| 2424 | crypt_stat, key_rec,
|
| 2425 | &written);
|
| 2426 | up_write(&(auth_tok_key->sem));
|
| 2427 | key_put(auth_tok_key);
|
| 2428 | if (rc) {
|
| 2429 | ecryptfs_printk(KERN_WARNING, "Error "
|
| 2430 | "writing tag 3 packet\n");
|
| 2431 | goto out_free;
|
| 2432 | }
|
| 2433 | (*len) += written;
|
| 2434 |
|
| 2435 | rc = write_tag_11_packet((dest_base + (*len)), &max,
|
| 2436 | key_rec->sig,
|
| 2437 | ECRYPTFS_SIG_SIZE, &written);
|
| 2438 | if (rc) {
|
| 2439 | ecryptfs_printk(KERN_ERR, "Error writing "
|
| 2440 | "auth tok signature packet\n");
|
| 2441 | goto out_free;
|
| 2442 | }
|
| 2443 | (*len) += written;
|
| 2444 | } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
|
| 2445 | rc = write_tag_1_packet(dest_base + (*len), &max,
|
| 2446 | auth_tok_key, auth_tok,
|
| 2447 | crypt_stat, key_rec, &written);
|
| 2448 | if (rc) {
|
| 2449 | ecryptfs_printk(KERN_WARNING, "Error "
|
| 2450 | "writing tag 1 packet\n");
|
| 2451 | goto out_free;
|
| 2452 | }
|
| 2453 | (*len) += written;
|
| 2454 | } else {
|
| 2455 | up_write(&(auth_tok_key->sem));
|
| 2456 | key_put(auth_tok_key);
|
| 2457 | ecryptfs_printk(KERN_WARNING, "Unsupported "
|
| 2458 | "authentication token type\n");
|
| 2459 | rc = -EINVAL;
|
| 2460 | goto out_free;
|
| 2461 | }
|
| 2462 | }
|
| 2463 | if (likely(max > 0)) {
|
| 2464 | dest_base[(*len)] = 0x00;
|
| 2465 | } else {
|
| 2466 | ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
|
| 2467 | rc = -EIO;
|
| 2468 | }
|
| 2469 | out_free:
|
| 2470 | kmem_cache_free(ecryptfs_key_record_cache, key_rec);
|
| 2471 | out:
|
| 2472 | if (rc)
|
| 2473 | (*len) = 0;
|
| 2474 | mutex_unlock(&crypt_stat->keysig_list_mutex);
|
| 2475 | return rc;
|
| 2476 | }
|
| 2477 |
|
| 2478 | struct kmem_cache *ecryptfs_key_sig_cache;
|
| 2479 |
|
| 2480 | int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
|
| 2481 | {
|
| 2482 | struct ecryptfs_key_sig *new_key_sig;
|
| 2483 |
|
| 2484 | new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
|
| 2485 | if (!new_key_sig)
|
| 2486 | return -ENOMEM;
|
| 2487 |
|
| 2488 | strscpy(new_key_sig->keysig, sig);
|
| 2489 |
|
| 2490 | list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
|
| 2491 |
|
| 2492 | return 0;
|
| 2493 | }
|
| 2494 |
|
| 2495 | struct kmem_cache *ecryptfs_global_auth_tok_cache;
|
| 2496 |
|
| 2497 | int
|
| 2498 | ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
|
| 2499 | char *sig, u32 global_auth_tok_flags)
|
| 2500 | {
|
| 2501 | struct ecryptfs_global_auth_tok *new_auth_tok;
|
| 2502 |
|
| 2503 | new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
|
| 2504 | GFP_KERNEL);
|
| 2505 | if (!new_auth_tok)
|
| 2506 | return -ENOMEM;
|
| 2507 |
|
| 2508 | strscpy(new_auth_tok->sig, sig);
|
| 2509 | new_auth_tok->flags = global_auth_tok_flags;
|
| 2510 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
|
| 2511 | list_add(&new_auth_tok->mount_crypt_stat_list,
|
| 2512 | &mount_crypt_stat->global_auth_tok_list);
|
| 2513 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
|
| 2514 | return 0;
|
| 2515 | }
|
| 2516 |
|