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TOMOYO Linux Cross Reference
Linux/fs/ecryptfs/keystore.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  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 <mhalcrow@us.ibm.com>
 10  *              Michael C. Thompson <mcthomps@us.ibm.com>
 11  *              Trevor S. Highland <trevor.highland@gmail.com>
 12  */
 13 
 14 #include <crypto/hash.h>
 15 #include <crypto/skcipher.h>
 16 #include <linux/string.h>
 17 #include <linux/pagemap.h>
 18 #include <linux/key.h>
 19 #include <linux/random.h>
 20 #include <linux/scatterlist.h>
 21 #include <linux/slab.h>
 22 #include "ecryptfs_kernel.h"
 23 
 24 /*
 25  * request_key returned an error instead of a valid key address;
 26  * determine the type of error, make appropriate log entries, and
 27  * return an error code.
 28  */
 29 static int process_request_key_err(long err_code)
 30 {
 31         int rc = 0;
 32 
 33         switch (err_code) {
 34         case -ENOKEY:
 35                 ecryptfs_printk(KERN_WARNING, "No key\n");
 36                 rc = -ENOENT;
 37                 break;
 38         case -EKEYEXPIRED:
 39                 ecryptfs_printk(KERN_WARNING, "Key expired\n");
 40                 rc = -ETIME;
 41                 break;
 42         case -EKEYREVOKED:
 43                 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
 44                 rc = -EINVAL;
 45                 break;
 46         default:
 47                 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
 48                                 "[0x%.16lx]\n", err_code);
 49                 rc = -EINVAL;
 50         }
 51         return rc;
 52 }
 53 
 54 static int process_find_global_auth_tok_for_sig_err(int err_code)
 55 {
 56         int rc = err_code;
 57 
 58         switch (err_code) {
 59         case -ENOENT:
 60                 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
 61                 break;
 62         case -EINVAL:
 63                 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
 64                 break;
 65         default:
 66                 rc = process_request_key_err(err_code);
 67                 break;
 68         }
 69         return rc;
 70 }
 71 
 72 /**
 73  * ecryptfs_parse_packet_length
 74  * @data: Pointer to memory containing length at offset
 75  * @size: This function writes the decoded size to this memory
 76  *        address; zero on error
 77  * @length_size: The number of bytes occupied by the encoded length
 78  *
 79  * Returns zero on success; non-zero on error
 80  */
 81 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
 82                                  size_t *length_size)
 83 {
 84         int rc = 0;
 85 
 86         (*length_size) = 0;
 87         (*size) = 0;
 88         if (data[0] < 192) {
 89                 /* One-byte length */
 90                 (*size) = data[0];
 91                 (*length_size) = 1;
 92         } else if (data[0] < 224) {
 93                 /* Two-byte length */
 94                 (*size) = (data[0] - 192) * 256;
 95                 (*size) += data[1] + 192;
 96                 (*length_size) = 2;
 97         } else if (data[0] == 255) {
 98                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
 99                 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
100                                 "supported\n");
101                 rc = -EINVAL;
102                 goto out;
103         } else {
104                 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
105                 rc = -EINVAL;
106                 goto out;
107         }
108 out:
109         return rc;
110 }
111 
112 /**
113  * ecryptfs_write_packet_length
114  * @dest: The byte array target into which to write the length. Must
115  *        have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
116  * @size: The length to write.
117  * @packet_size_length: The number of bytes used to encode the packet
118  *                      length is written to this address.
119  *
120  * Returns zero on success; non-zero on error.
121  */
122 int ecryptfs_write_packet_length(char *dest, size_t size,
123                                  size_t *packet_size_length)
124 {
125         int rc = 0;
126 
127         if (size < 192) {
128                 dest[0] = size;
129                 (*packet_size_length) = 1;
130         } else if (size < 65536) {
131                 dest[0] = (((size - 192) / 256) + 192);
132                 dest[1] = ((size - 192) % 256);
133                 (*packet_size_length) = 2;
134         } else {
135                 /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
136                 rc = -EINVAL;
137                 ecryptfs_printk(KERN_WARNING,
138                                 "Unsupported packet size: [%zd]\n", size);
139         }
140         return rc;
141 }
142 
143 static int
144 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
145                     char **packet, size_t *packet_len)
146 {
147         size_t i = 0;
148         size_t data_len;
149         size_t packet_size_len;
150         char *message;
151         int rc;
152 
153         /*
154          *              ***** TAG 64 Packet Format *****
155          *    | Content Type                       | 1 byte       |
156          *    | Key Identifier Size                | 1 or 2 bytes |
157          *    | Key Identifier                     | arbitrary    |
158          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
159          *    | Encrypted File Encryption Key      | arbitrary    |
160          */
161         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
162                     + session_key->encrypted_key_size);
163         *packet = kmalloc(data_len, GFP_KERNEL);
164         message = *packet;
165         if (!message) {
166                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
167                 rc = -ENOMEM;
168                 goto out;
169         }
170         message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
171         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
172                                           &packet_size_len);
173         if (rc) {
174                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
175                                 "header; cannot generate packet length\n");
176                 goto out;
177         }
178         i += packet_size_len;
179         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
180         i += ECRYPTFS_SIG_SIZE_HEX;
181         rc = ecryptfs_write_packet_length(&message[i],
182                                           session_key->encrypted_key_size,
183                                           &packet_size_len);
184         if (rc) {
185                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
186                                 "header; cannot generate packet length\n");
187                 goto out;
188         }
189         i += packet_size_len;
190         memcpy(&message[i], session_key->encrypted_key,
191                session_key->encrypted_key_size);
192         i += session_key->encrypted_key_size;
193         *packet_len = i;
194 out:
195         return rc;
196 }
197 
198 static int
199 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
200                     struct ecryptfs_message *msg)
201 {
202         size_t i = 0;
203         char *data;
204         size_t data_len;
205         size_t m_size;
206         size_t message_len;
207         u16 checksum = 0;
208         u16 expected_checksum = 0;
209         int rc;
210 
211         /*
212          *              ***** TAG 65 Packet Format *****
213          *         | Content Type             | 1 byte       |
214          *         | Status Indicator         | 1 byte       |
215          *         | File Encryption Key Size | 1 or 2 bytes |
216          *         | File Encryption Key      | arbitrary    |
217          */
218         message_len = msg->data_len;
219         data = msg->data;
220         if (message_len < 4) {
221                 rc = -EIO;
222                 goto out;
223         }
224         if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
225                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
226                 rc = -EIO;
227                 goto out;
228         }
229         if (data[i++]) {
230                 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
231                                 "[%d]\n", data[i-1]);
232                 rc = -EIO;
233                 goto out;
234         }
235         rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
236         if (rc) {
237                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
238                                 "rc = [%d]\n", rc);
239                 goto out;
240         }
241         i += data_len;
242         if (message_len < (i + m_size)) {
243                 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
244                                 "is shorter than expected\n");
245                 rc = -EIO;
246                 goto out;
247         }
248         if (m_size < 3) {
249                 ecryptfs_printk(KERN_ERR,
250                                 "The decrypted key is not long enough to "
251                                 "include a cipher code and checksum\n");
252                 rc = -EIO;
253                 goto out;
254         }
255         *cipher_code = data[i++];
256         /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
257         session_key->decrypted_key_size = m_size - 3;
258         if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
259                 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
260                                 "the maximum key size [%d]\n",
261                                 session_key->decrypted_key_size,
262                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
263                 rc = -EIO;
264                 goto out;
265         }
266         memcpy(session_key->decrypted_key, &data[i],
267                session_key->decrypted_key_size);
268         i += session_key->decrypted_key_size;
269         expected_checksum += (unsigned char)(data[i++]) << 8;
270         expected_checksum += (unsigned char)(data[i++]);
271         for (i = 0; i < session_key->decrypted_key_size; i++)
272                 checksum += session_key->decrypted_key[i];
273         if (expected_checksum != checksum) {
274                 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
275                                 "encryption  key; expected [%x]; calculated "
276                                 "[%x]\n", expected_checksum, checksum);
277                 rc = -EIO;
278         }
279 out:
280         return rc;
281 }
282 
283 
284 static int
285 write_tag_66_packet(char *signature, u8 cipher_code,
286                     struct ecryptfs_crypt_stat *crypt_stat, char **packet,
287                     size_t *packet_len)
288 {
289         size_t i = 0;
290         size_t j;
291         size_t data_len;
292         size_t checksum = 0;
293         size_t packet_size_len;
294         char *message;
295         int rc;
296 
297         /*
298          *              ***** TAG 66 Packet Format *****
299          *         | Content Type             | 1 byte       |
300          *         | Key Identifier Size      | 1 or 2 bytes |
301          *         | Key Identifier           | arbitrary    |
302          *         | File Encryption Key Size | 1 or 2 bytes |
303          *         | File Encryption Key      | arbitrary    |
304          */
305         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
306         *packet = kmalloc(data_len, GFP_KERNEL);
307         message = *packet;
308         if (!message) {
309                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
310                 rc = -ENOMEM;
311                 goto out;
312         }
313         message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
314         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
315                                           &packet_size_len);
316         if (rc) {
317                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
318                                 "header; cannot generate packet length\n");
319                 goto out;
320         }
321         i += packet_size_len;
322         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
323         i += ECRYPTFS_SIG_SIZE_HEX;
324         /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
325         rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
326                                           &packet_size_len);
327         if (rc) {
328                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
329                                 "header; cannot generate packet length\n");
330                 goto out;
331         }
332         i += packet_size_len;
333         message[i++] = cipher_code;
334         memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
335         i += crypt_stat->key_size;
336         for (j = 0; j < crypt_stat->key_size; j++)
337                 checksum += crypt_stat->key[j];
338         message[i++] = (checksum / 256) % 256;
339         message[i++] = (checksum % 256);
340         *packet_len = i;
341 out:
342         return rc;
343 }
344 
345 static int
346 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
347                     struct ecryptfs_message *msg)
348 {
349         size_t i = 0;
350         char *data;
351         size_t data_len;
352         size_t message_len;
353         int rc;
354 
355         /*
356          *              ***** TAG 65 Packet Format *****
357          *    | Content Type                       | 1 byte       |
358          *    | Status Indicator                   | 1 byte       |
359          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
360          *    | Encrypted File Encryption Key      | arbitrary    |
361          */
362         message_len = msg->data_len;
363         data = msg->data;
364         /* verify that everything through the encrypted FEK size is present */
365         if (message_len < 4) {
366                 rc = -EIO;
367                 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
368                        "message length is [%d]\n", __func__, message_len, 4);
369                 goto out;
370         }
371         if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
372                 rc = -EIO;
373                 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
374                        __func__);
375                 goto out;
376         }
377         if (data[i++]) {
378                 rc = -EIO;
379                 printk(KERN_ERR "%s: Status indicator has non zero "
380                        "value [%d]\n", __func__, data[i-1]);
381 
382                 goto out;
383         }
384         rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
385                                           &data_len);
386         if (rc) {
387                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
388                                 "rc = [%d]\n", rc);
389                 goto out;
390         }
391         i += data_len;
392         if (message_len < (i + key_rec->enc_key_size)) {
393                 rc = -EIO;
394                 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
395                        __func__, message_len, (i + key_rec->enc_key_size));
396                 goto out;
397         }
398         if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
399                 rc = -EIO;
400                 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
401                        "the maximum key size [%d]\n", __func__,
402                        key_rec->enc_key_size,
403                        ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
404                 goto out;
405         }
406         memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
407 out:
408         return rc;
409 }
410 
411 /**
412  * ecryptfs_verify_version
413  * @version: The version number to confirm
414  *
415  * Returns zero on good version; non-zero otherwise
416  */
417 static int ecryptfs_verify_version(u16 version)
418 {
419         int rc = 0;
420         unsigned char major;
421         unsigned char minor;
422 
423         major = ((version >> 8) & 0xFF);
424         minor = (version & 0xFF);
425         if (major != ECRYPTFS_VERSION_MAJOR) {
426                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
427                                 "Expected [%d]; got [%d]\n",
428                                 ECRYPTFS_VERSION_MAJOR, major);
429                 rc = -EINVAL;
430                 goto out;
431         }
432         if (minor != ECRYPTFS_VERSION_MINOR) {
433                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
434                                 "Expected [%d]; got [%d]\n",
435                                 ECRYPTFS_VERSION_MINOR, minor);
436                 rc = -EINVAL;
437                 goto out;
438         }
439 out:
440         return rc;
441 }
442 
443 /**
444  * ecryptfs_verify_auth_tok_from_key
445  * @auth_tok_key: key containing the authentication token
446  * @auth_tok: authentication token
447  *
448  * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
449  * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
450  */
451 static int
452 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
453                                   struct ecryptfs_auth_tok **auth_tok)
454 {
455         int rc = 0;
456 
457         (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
458         if (IS_ERR(*auth_tok)) {
459                 rc = PTR_ERR(*auth_tok);
460                 *auth_tok = NULL;
461                 goto out;
462         }
463 
464         if (ecryptfs_verify_version((*auth_tok)->version)) {
465                 printk(KERN_ERR "Data structure version mismatch. Userspace "
466                        "tools must match eCryptfs kernel module with major "
467                        "version [%d] and minor version [%d]\n",
468                        ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
469                 rc = -EINVAL;
470                 goto out;
471         }
472         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
473             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
474                 printk(KERN_ERR "Invalid auth_tok structure "
475                        "returned from key query\n");
476                 rc = -EINVAL;
477                 goto out;
478         }
479 out:
480         return rc;
481 }
482 
483 static int
484 ecryptfs_find_global_auth_tok_for_sig(
485         struct key **auth_tok_key,
486         struct ecryptfs_auth_tok **auth_tok,
487         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
488 {
489         struct ecryptfs_global_auth_tok *walker;
490         int rc = 0;
491 
492         (*auth_tok_key) = NULL;
493         (*auth_tok) = NULL;
494         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
495         list_for_each_entry(walker,
496                             &mount_crypt_stat->global_auth_tok_list,
497                             mount_crypt_stat_list) {
498                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
499                         continue;
500 
501                 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
502                         rc = -EINVAL;
503                         goto out;
504                 }
505 
506                 rc = key_validate(walker->global_auth_tok_key);
507                 if (rc) {
508                         if (rc == -EKEYEXPIRED)
509                                 goto out;
510                         goto out_invalid_auth_tok;
511                 }
512 
513                 down_write(&(walker->global_auth_tok_key->sem));
514                 rc = ecryptfs_verify_auth_tok_from_key(
515                                 walker->global_auth_tok_key, auth_tok);
516                 if (rc)
517                         goto out_invalid_auth_tok_unlock;
518 
519                 (*auth_tok_key) = walker->global_auth_tok_key;
520                 key_get(*auth_tok_key);
521                 goto out;
522         }
523         rc = -ENOENT;
524         goto out;
525 out_invalid_auth_tok_unlock:
526         up_write(&(walker->global_auth_tok_key->sem));
527 out_invalid_auth_tok:
528         printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
529         walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
530         key_put(walker->global_auth_tok_key);
531         walker->global_auth_tok_key = NULL;
532 out:
533         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
534         return rc;
535 }
536 
537 /**
538  * ecryptfs_find_auth_tok_for_sig
539  * @auth_tok_key: key containing the authentication token
540  * @auth_tok: Set to the matching auth_tok; NULL if not found
541  * @mount_crypt_stat: inode crypt_stat crypto context
542  * @sig: Sig of auth_tok to find
543  *
544  * For now, this function simply looks at the registered auth_tok's
545  * linked off the mount_crypt_stat, so all the auth_toks that can be
546  * used must be registered at mount time. This function could
547  * potentially try a lot harder to find auth_tok's (e.g., by calling
548  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
549  * that static registration of auth_tok's will no longer be necessary.
550  *
551  * Returns zero on no error; non-zero on error
552  */
553 static int
554 ecryptfs_find_auth_tok_for_sig(
555         struct key **auth_tok_key,
556         struct ecryptfs_auth_tok **auth_tok,
557         struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
558         char *sig)
559 {
560         int rc = 0;
561 
562         rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
563                                                    mount_crypt_stat, sig);
564         if (rc == -ENOENT) {
565                 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
566                  * mount_crypt_stat structure, we prevent to use auth toks that
567                  * are not inserted through the ecryptfs_add_global_auth_tok
568                  * function.
569                  */
570                 if (mount_crypt_stat->flags
571                                 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
572                         return -EINVAL;
573 
574                 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
575                                                        sig);
576         }
577         return rc;
578 }
579 
580 /*
581  * write_tag_70_packet can gobble a lot of stack space. We stuff most
582  * of the function's parameters in a kmalloc'd struct to help reduce
583  * eCryptfs' overall stack usage.
584  */
585 struct ecryptfs_write_tag_70_packet_silly_stack {
586         u8 cipher_code;
587         size_t max_packet_size;
588         size_t packet_size_len;
589         size_t block_aligned_filename_size;
590         size_t block_size;
591         size_t i;
592         size_t j;
593         size_t num_rand_bytes;
594         struct mutex *tfm_mutex;
595         char *block_aligned_filename;
596         struct ecryptfs_auth_tok *auth_tok;
597         struct scatterlist src_sg[2];
598         struct scatterlist dst_sg[2];
599         struct crypto_skcipher *skcipher_tfm;
600         struct skcipher_request *skcipher_req;
601         char iv[ECRYPTFS_MAX_IV_BYTES];
602         char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
603         char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
604         struct crypto_shash *hash_tfm;
605         struct shash_desc *hash_desc;
606 };
607 
608 /*
609  * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
610  * @filename: NULL-terminated filename string
611  *
612  * This is the simplest mechanism for achieving filename encryption in
613  * eCryptfs. It encrypts the given filename with the mount-wide
614  * filename encryption key (FNEK) and stores it in a packet to @dest,
615  * which the callee will encode and write directly into the dentry
616  * name.
617  */
618 int
619 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
620                              size_t *packet_size,
621                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
622                              char *filename, size_t filename_size)
623 {
624         struct ecryptfs_write_tag_70_packet_silly_stack *s;
625         struct key *auth_tok_key = NULL;
626         int rc = 0;
627 
628         s = kzalloc(sizeof(*s), GFP_KERNEL);
629         if (!s)
630                 return -ENOMEM;
631 
632         (*packet_size) = 0;
633         rc = ecryptfs_find_auth_tok_for_sig(
634                 &auth_tok_key,
635                 &s->auth_tok, mount_crypt_stat,
636                 mount_crypt_stat->global_default_fnek_sig);
637         if (rc) {
638                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
639                        "fnek sig [%s]; rc = [%d]\n", __func__,
640                        mount_crypt_stat->global_default_fnek_sig, rc);
641                 goto out;
642         }
643         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
644                 &s->skcipher_tfm,
645                 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
646         if (unlikely(rc)) {
647                 printk(KERN_ERR "Internal error whilst attempting to get "
648                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
649                        mount_crypt_stat->global_default_fn_cipher_name, rc);
650                 goto out;
651         }
652         mutex_lock(s->tfm_mutex);
653         s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
654         /* Plus one for the \0 separator between the random prefix
655          * and the plaintext filename */
656         s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
657         s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
658         if ((s->block_aligned_filename_size % s->block_size) != 0) {
659                 s->num_rand_bytes += (s->block_size
660                                       - (s->block_aligned_filename_size
661                                          % s->block_size));
662                 s->block_aligned_filename_size = (s->num_rand_bytes
663                                                   + filename_size);
664         }
665         /* Octet 0: Tag 70 identifier
666          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
667          *              and block-aligned encrypted filename size)
668          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
669          * Octet N2-N3: Cipher identifier (1 octet)
670          * Octets N3-N4: Block-aligned encrypted filename
671          *  - Consists of a minimum number of random characters, a \0
672          *    separator, and then the filename */
673         s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
674                               + s->block_aligned_filename_size);
675         if (!dest) {
676                 (*packet_size) = s->max_packet_size;
677                 goto out_unlock;
678         }
679         if (s->max_packet_size > (*remaining_bytes)) {
680                 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
681                        "[%zd] available\n", __func__, s->max_packet_size,
682                        (*remaining_bytes));
683                 rc = -EINVAL;
684                 goto out_unlock;
685         }
686 
687         s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
688         if (!s->skcipher_req) {
689                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
690                        "skcipher_request_alloc for %s\n", __func__,
691                        crypto_skcipher_driver_name(s->skcipher_tfm));
692                 rc = -ENOMEM;
693                 goto out_unlock;
694         }
695 
696         skcipher_request_set_callback(s->skcipher_req,
697                                       CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
698 
699         s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
700                                             GFP_KERNEL);
701         if (!s->block_aligned_filename) {
702                 rc = -ENOMEM;
703                 goto out_unlock;
704         }
705         dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
706         rc = ecryptfs_write_packet_length(&dest[s->i],
707                                           (ECRYPTFS_SIG_SIZE
708                                            + 1 /* Cipher code */
709                                            + s->block_aligned_filename_size),
710                                           &s->packet_size_len);
711         if (rc) {
712                 printk(KERN_ERR "%s: Error generating tag 70 packet "
713                        "header; cannot generate packet length; rc = [%d]\n",
714                        __func__, rc);
715                 goto out_free_unlock;
716         }
717         s->i += s->packet_size_len;
718         ecryptfs_from_hex(&dest[s->i],
719                           mount_crypt_stat->global_default_fnek_sig,
720                           ECRYPTFS_SIG_SIZE);
721         s->i += ECRYPTFS_SIG_SIZE;
722         s->cipher_code = ecryptfs_code_for_cipher_string(
723                 mount_crypt_stat->global_default_fn_cipher_name,
724                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
725         if (s->cipher_code == 0) {
726                 printk(KERN_WARNING "%s: Unable to generate code for "
727                        "cipher [%s] with key bytes [%zd]\n", __func__,
728                        mount_crypt_stat->global_default_fn_cipher_name,
729                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
730                 rc = -EINVAL;
731                 goto out_free_unlock;
732         }
733         dest[s->i++] = s->cipher_code;
734         /* TODO: Support other key modules than passphrase for
735          * filename encryption */
736         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
737                 rc = -EOPNOTSUPP;
738                 printk(KERN_INFO "%s: Filename encryption only supports "
739                        "password tokens\n", __func__);
740                 goto out_free_unlock;
741         }
742         s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
743         if (IS_ERR(s->hash_tfm)) {
744                         rc = PTR_ERR(s->hash_tfm);
745                         printk(KERN_ERR "%s: Error attempting to "
746                                "allocate hash crypto context; rc = [%d]\n",
747                                __func__, rc);
748                         goto out_free_unlock;
749         }
750 
751         s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
752                                crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
753         if (!s->hash_desc) {
754                 rc = -ENOMEM;
755                 goto out_release_free_unlock;
756         }
757 
758         s->hash_desc->tfm = s->hash_tfm;
759 
760         rc = crypto_shash_digest(s->hash_desc,
761                                  (u8 *)s->auth_tok->token.password.session_key_encryption_key,
762                                  s->auth_tok->token.password.session_key_encryption_key_bytes,
763                                  s->hash);
764         if (rc) {
765                 printk(KERN_ERR
766                        "%s: Error computing crypto hash; rc = [%d]\n",
767                        __func__, rc);
768                 goto out_release_free_unlock;
769         }
770         for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
771                 s->block_aligned_filename[s->j] =
772                         s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
773                 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
774                     == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
775                         rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
776                                                 ECRYPTFS_TAG_70_DIGEST_SIZE,
777                                                 s->tmp_hash);
778                         if (rc) {
779                                 printk(KERN_ERR
780                                        "%s: Error computing crypto hash; "
781                                        "rc = [%d]\n", __func__, rc);
782                                 goto out_release_free_unlock;
783                         }
784                         memcpy(s->hash, s->tmp_hash,
785                                ECRYPTFS_TAG_70_DIGEST_SIZE);
786                 }
787                 if (s->block_aligned_filename[s->j] == '\0')
788                         s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
789         }
790         memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
791                filename_size);
792         rc = virt_to_scatterlist(s->block_aligned_filename,
793                                  s->block_aligned_filename_size, s->src_sg, 2);
794         if (rc < 1) {
795                 printk(KERN_ERR "%s: Internal error whilst attempting to "
796                        "convert filename memory to scatterlist; rc = [%d]. "
797                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
798                        s->block_aligned_filename_size);
799                 goto out_release_free_unlock;
800         }
801         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
802                                  s->dst_sg, 2);
803         if (rc < 1) {
804                 printk(KERN_ERR "%s: Internal error whilst attempting to "
805                        "convert encrypted filename memory to scatterlist; "
806                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
807                        __func__, rc, s->block_aligned_filename_size);
808                 goto out_release_free_unlock;
809         }
810         /* The characters in the first block effectively do the job
811          * of the IV here, so we just use 0's for the IV. Note the
812          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
813          * >= ECRYPTFS_MAX_IV_BYTES. */
814         rc = crypto_skcipher_setkey(
815                 s->skcipher_tfm,
816                 s->auth_tok->token.password.session_key_encryption_key,
817                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
818         if (rc < 0) {
819                 printk(KERN_ERR "%s: Error setting key for crypto context; "
820                        "rc = [%d]. s->auth_tok->token.password.session_key_"
821                        "encryption_key = [0x%p]; mount_crypt_stat->"
822                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
823                        rc,
824                        s->auth_tok->token.password.session_key_encryption_key,
825                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
826                 goto out_release_free_unlock;
827         }
828         skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
829                                    s->block_aligned_filename_size, s->iv);
830         rc = crypto_skcipher_encrypt(s->skcipher_req);
831         if (rc) {
832                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
833                        "rc = [%d]\n", __func__, rc);
834                 goto out_release_free_unlock;
835         }
836         s->i += s->block_aligned_filename_size;
837         (*packet_size) = s->i;
838         (*remaining_bytes) -= (*packet_size);
839 out_release_free_unlock:
840         crypto_free_shash(s->hash_tfm);
841 out_free_unlock:
842         kfree_sensitive(s->block_aligned_filename);
843 out_unlock:
844         mutex_unlock(s->tfm_mutex);
845 out:
846         if (auth_tok_key) {
847                 up_write(&(auth_tok_key->sem));
848                 key_put(auth_tok_key);
849         }
850         skcipher_request_free(s->skcipher_req);
851         kfree_sensitive(s->hash_desc);
852         kfree(s);
853         return rc;
854 }
855 
856 struct ecryptfs_parse_tag_70_packet_silly_stack {
857         u8 cipher_code;
858         size_t max_packet_size;
859         size_t packet_size_len;
860         size_t parsed_tag_70_packet_size;
861         size_t block_aligned_filename_size;
862         size_t block_size;
863         size_t i;
864         struct mutex *tfm_mutex;
865         char *decrypted_filename;
866         struct ecryptfs_auth_tok *auth_tok;
867         struct scatterlist src_sg[2];
868         struct scatterlist dst_sg[2];
869         struct crypto_skcipher *skcipher_tfm;
870         struct skcipher_request *skcipher_req;
871         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
872         char iv[ECRYPTFS_MAX_IV_BYTES];
873         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
874 };
875 
876 /**
877  * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
878  * @filename: This function kmalloc's the memory for the filename
879  * @filename_size: This function sets this to the amount of memory
880  *                 kmalloc'd for the filename
881  * @packet_size: This function sets this to the the number of octets
882  *               in the packet parsed
883  * @mount_crypt_stat: The mount-wide cryptographic context
884  * @data: The memory location containing the start of the tag 70
885  *        packet
886  * @max_packet_size: The maximum legal size of the packet to be parsed
887  *                   from @data
888  *
889  * Returns zero on success; non-zero otherwise
890  */
891 int
892 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
893                              size_t *packet_size,
894                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
895                              char *data, size_t max_packet_size)
896 {
897         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
898         struct key *auth_tok_key = NULL;
899         int rc = 0;
900 
901         (*packet_size) = 0;
902         (*filename_size) = 0;
903         (*filename) = NULL;
904         s = kzalloc(sizeof(*s), GFP_KERNEL);
905         if (!s)
906                 return -ENOMEM;
907 
908         if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
909                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
910                        "at least [%d]\n", __func__, max_packet_size,
911                        ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
912                 rc = -EINVAL;
913                 goto out;
914         }
915         /* Octet 0: Tag 70 identifier
916          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
917          *              and block-aligned encrypted filename size)
918          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
919          * Octet N2-N3: Cipher identifier (1 octet)
920          * Octets N3-N4: Block-aligned encrypted filename
921          *  - Consists of a minimum number of random numbers, a \0
922          *    separator, and then the filename */
923         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
924                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
925                        "tag [0x%.2x]\n", __func__,
926                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
927                 rc = -EINVAL;
928                 goto out;
929         }
930         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
931                                           &s->parsed_tag_70_packet_size,
932                                           &s->packet_size_len);
933         if (rc) {
934                 printk(KERN_WARNING "%s: Error parsing packet length; "
935                        "rc = [%d]\n", __func__, rc);
936                 goto out;
937         }
938         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
939                                           - ECRYPTFS_SIG_SIZE - 1);
940         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
941             > max_packet_size) {
942                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
943                        "size is [%zd]\n", __func__, max_packet_size,
944                        (1 + s->packet_size_len + 1
945                         + s->block_aligned_filename_size));
946                 rc = -EINVAL;
947                 goto out;
948         }
949         (*packet_size) += s->packet_size_len;
950         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
951                         ECRYPTFS_SIG_SIZE);
952         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
953         (*packet_size) += ECRYPTFS_SIG_SIZE;
954         s->cipher_code = data[(*packet_size)++];
955         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
956         if (rc) {
957                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
958                        __func__, s->cipher_code);
959                 goto out;
960         }
961         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
962                                             &s->auth_tok, mount_crypt_stat,
963                                             s->fnek_sig_hex);
964         if (rc) {
965                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
966                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
967                        rc);
968                 goto out;
969         }
970         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
971                                                         &s->tfm_mutex,
972                                                         s->cipher_string);
973         if (unlikely(rc)) {
974                 printk(KERN_ERR "Internal error whilst attempting to get "
975                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
976                        s->cipher_string, rc);
977                 goto out;
978         }
979         mutex_lock(s->tfm_mutex);
980         rc = virt_to_scatterlist(&data[(*packet_size)],
981                                  s->block_aligned_filename_size, s->src_sg, 2);
982         if (rc < 1) {
983                 printk(KERN_ERR "%s: Internal error whilst attempting to "
984                        "convert encrypted filename memory to scatterlist; "
985                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
986                        __func__, rc, s->block_aligned_filename_size);
987                 goto out_unlock;
988         }
989         (*packet_size) += s->block_aligned_filename_size;
990         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
991                                         GFP_KERNEL);
992         if (!s->decrypted_filename) {
993                 rc = -ENOMEM;
994                 goto out_unlock;
995         }
996         rc = virt_to_scatterlist(s->decrypted_filename,
997                                  s->block_aligned_filename_size, s->dst_sg, 2);
998         if (rc < 1) {
999                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1000                        "convert decrypted filename memory to scatterlist; "
1001                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1002                        __func__, rc, s->block_aligned_filename_size);
1003                 goto out_free_unlock;
1004         }
1005 
1006         s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
1007         if (!s->skcipher_req) {
1008                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1009                        "skcipher_request_alloc for %s\n", __func__,
1010                        crypto_skcipher_driver_name(s->skcipher_tfm));
1011                 rc = -ENOMEM;
1012                 goto out_free_unlock;
1013         }
1014 
1015         skcipher_request_set_callback(s->skcipher_req,
1016                                       CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
1017 
1018         /* The characters in the first block effectively do the job of
1019          * the IV here, so we just use 0's for the IV. Note the
1020          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1021          * >= ECRYPTFS_MAX_IV_BYTES. */
1022         /* TODO: Support other key modules than passphrase for
1023          * filename encryption */
1024         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1025                 rc = -EOPNOTSUPP;
1026                 printk(KERN_INFO "%s: Filename encryption only supports "
1027                        "password tokens\n", __func__);
1028                 goto out_free_unlock;
1029         }
1030         rc = crypto_skcipher_setkey(
1031                 s->skcipher_tfm,
1032                 s->auth_tok->token.password.session_key_encryption_key,
1033                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1034         if (rc < 0) {
1035                 printk(KERN_ERR "%s: Error setting key for crypto context; "
1036                        "rc = [%d]. s->auth_tok->token.password.session_key_"
1037                        "encryption_key = [0x%p]; mount_crypt_stat->"
1038                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1039                        rc,
1040                        s->auth_tok->token.password.session_key_encryption_key,
1041                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
1042                 goto out_free_unlock;
1043         }
1044         skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
1045                                    s->block_aligned_filename_size, s->iv);
1046         rc = crypto_skcipher_decrypt(s->skcipher_req);
1047         if (rc) {
1048                 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1049                        "rc = [%d]\n", __func__, rc);
1050                 goto out_free_unlock;
1051         }
1052 
1053         while (s->i < s->block_aligned_filename_size &&
1054                s->decrypted_filename[s->i] != '\0')
1055                 s->i++;
1056         if (s->i == s->block_aligned_filename_size) {
1057                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1058                        "find valid separator between random characters and "
1059                        "the filename\n", __func__);
1060                 rc = -EINVAL;
1061                 goto out_free_unlock;
1062         }
1063         s->i++;
1064         (*filename_size) = (s->block_aligned_filename_size - s->i);
1065         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1066                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1067                        "invalid\n", __func__, (*filename_size));
1068                 rc = -EINVAL;
1069                 goto out_free_unlock;
1070         }
1071         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1072         if (!(*filename)) {
1073                 rc = -ENOMEM;
1074                 goto out_free_unlock;
1075         }
1076         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1077         (*filename)[(*filename_size)] = '\0';
1078 out_free_unlock:
1079         kfree(s->decrypted_filename);
1080 out_unlock:
1081         mutex_unlock(s->tfm_mutex);
1082 out:
1083         if (rc) {
1084                 (*packet_size) = 0;
1085                 (*filename_size) = 0;
1086                 (*filename) = NULL;
1087         }
1088         if (auth_tok_key) {
1089                 up_write(&(auth_tok_key->sem));
1090                 key_put(auth_tok_key);
1091         }
1092         skcipher_request_free(s->skcipher_req);
1093         kfree(s);
1094         return rc;
1095 }
1096 
1097 static int
1098 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1099 {
1100         int rc = 0;
1101 
1102         (*sig) = NULL;
1103         switch (auth_tok->token_type) {
1104         case ECRYPTFS_PASSWORD:
1105                 (*sig) = auth_tok->token.password.signature;
1106                 break;
1107         case ECRYPTFS_PRIVATE_KEY:
1108                 (*sig) = auth_tok->token.private_key.signature;
1109                 break;
1110         default:
1111                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1112                        auth_tok->token_type);
1113                 rc = -EINVAL;
1114         }
1115         return rc;
1116 }
1117 
1118 /**
1119  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1120  * @auth_tok: The key authentication token used to decrypt the session key
1121  * @crypt_stat: The cryptographic context
1122  *
1123  * Returns zero on success; non-zero error otherwise.
1124  */
1125 static int
1126 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1127                                   struct ecryptfs_crypt_stat *crypt_stat)
1128 {
1129         u8 cipher_code = 0;
1130         struct ecryptfs_msg_ctx *msg_ctx;
1131         struct ecryptfs_message *msg = NULL;
1132         char *auth_tok_sig;
1133         char *payload = NULL;
1134         size_t payload_len = 0;
1135         int rc;
1136 
1137         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1138         if (rc) {
1139                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1140                        auth_tok->token_type);
1141                 goto out;
1142         }
1143         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1144                                  &payload, &payload_len);
1145         if (rc) {
1146                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1147                 goto out;
1148         }
1149         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1150         if (rc) {
1151                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1152                                 "ecryptfsd: %d\n", rc);
1153                 goto out;
1154         }
1155         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1156         if (rc) {
1157                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1158                                 "from the user space daemon\n");
1159                 rc = -EIO;
1160                 goto out;
1161         }
1162         rc = parse_tag_65_packet(&(auth_tok->session_key),
1163                                  &cipher_code, msg);
1164         if (rc) {
1165                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1166                        rc);
1167                 goto out;
1168         }
1169         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1170         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1171                auth_tok->session_key.decrypted_key_size);
1172         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1173         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1174         if (rc) {
1175                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1176                                 cipher_code);
1177                 goto out;
1178         }
1179         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1180         if (ecryptfs_verbosity > 0) {
1181                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1182                 ecryptfs_dump_hex(crypt_stat->key,
1183                                   crypt_stat->key_size);
1184         }
1185 out:
1186         kfree(msg);
1187         kfree(payload);
1188         return rc;
1189 }
1190 
1191 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1192 {
1193         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1194         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1195 
1196         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1197                                  auth_tok_list_head, list) {
1198                 list_del(&auth_tok_list_item->list);
1199                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1200                                 auth_tok_list_item);
1201         }
1202 }
1203 
1204 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1205 
1206 /**
1207  * parse_tag_1_packet
1208  * @crypt_stat: The cryptographic context to modify based on packet contents
1209  * @data: The raw bytes of the packet.
1210  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1211  *                 a new authentication token will be placed at the
1212  *                 end of this list for this packet.
1213  * @new_auth_tok: Pointer to a pointer to memory that this function
1214  *                allocates; sets the memory address of the pointer to
1215  *                NULL on error. This object is added to the
1216  *                auth_tok_list.
1217  * @packet_size: This function writes the size of the parsed packet
1218  *               into this memory location; zero on error.
1219  * @max_packet_size: The maximum allowable packet size
1220  *
1221  * Returns zero on success; non-zero on error.
1222  */
1223 static int
1224 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1225                    unsigned char *data, struct list_head *auth_tok_list,
1226                    struct ecryptfs_auth_tok **new_auth_tok,
1227                    size_t *packet_size, size_t max_packet_size)
1228 {
1229         size_t body_size;
1230         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1231         size_t length_size;
1232         int rc = 0;
1233 
1234         (*packet_size) = 0;
1235         (*new_auth_tok) = NULL;
1236         /**
1237          * This format is inspired by OpenPGP; see RFC 2440
1238          * packet tag 1
1239          *
1240          * Tag 1 identifier (1 byte)
1241          * Max Tag 1 packet size (max 3 bytes)
1242          * Version (1 byte)
1243          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1244          * Cipher identifier (1 byte)
1245          * Encrypted key size (arbitrary)
1246          *
1247          * 12 bytes minimum packet size
1248          */
1249         if (unlikely(max_packet_size < 12)) {
1250                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1251                 rc = -EINVAL;
1252                 goto out;
1253         }
1254         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1255                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1256                        ECRYPTFS_TAG_1_PACKET_TYPE);
1257                 rc = -EINVAL;
1258                 goto out;
1259         }
1260         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1261          * at end of function upon failure */
1262         auth_tok_list_item =
1263                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1264                                   GFP_KERNEL);
1265         if (!auth_tok_list_item) {
1266                 printk(KERN_ERR "Unable to allocate memory\n");
1267                 rc = -ENOMEM;
1268                 goto out;
1269         }
1270         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1271         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1272                                           &length_size);
1273         if (rc) {
1274                 printk(KERN_WARNING "Error parsing packet length; "
1275                        "rc = [%d]\n", rc);
1276                 goto out_free;
1277         }
1278         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1279                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1280                 rc = -EINVAL;
1281                 goto out_free;
1282         }
1283         (*packet_size) += length_size;
1284         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1285                 printk(KERN_WARNING "Packet size exceeds max\n");
1286                 rc = -EINVAL;
1287                 goto out_free;
1288         }
1289         if (unlikely(data[(*packet_size)++] != 0x03)) {
1290                 printk(KERN_WARNING "Unknown version number [%d]\n",
1291                        data[(*packet_size) - 1]);
1292                 rc = -EINVAL;
1293                 goto out_free;
1294         }
1295         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1296                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1297         *packet_size += ECRYPTFS_SIG_SIZE;
1298         /* This byte is skipped because the kernel does not need to
1299          * know which public key encryption algorithm was used */
1300         (*packet_size)++;
1301         (*new_auth_tok)->session_key.encrypted_key_size =
1302                 body_size - (ECRYPTFS_SIG_SIZE + 2);
1303         if ((*new_auth_tok)->session_key.encrypted_key_size
1304             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1305                 printk(KERN_WARNING "Tag 1 packet contains key larger "
1306                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1307                 rc = -EINVAL;
1308                 goto out_free;
1309         }
1310         memcpy((*new_auth_tok)->session_key.encrypted_key,
1311                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1312         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1313         (*new_auth_tok)->session_key.flags &=
1314                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1315         (*new_auth_tok)->session_key.flags |=
1316                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1317         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1318         (*new_auth_tok)->flags = 0;
1319         (*new_auth_tok)->session_key.flags &=
1320                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1321         (*new_auth_tok)->session_key.flags &=
1322                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1323         list_add(&auth_tok_list_item->list, auth_tok_list);
1324         goto out;
1325 out_free:
1326         (*new_auth_tok) = NULL;
1327         memset(auth_tok_list_item, 0,
1328                sizeof(struct ecryptfs_auth_tok_list_item));
1329         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1330                         auth_tok_list_item);
1331 out:
1332         if (rc)
1333                 (*packet_size) = 0;
1334         return rc;
1335 }
1336 
1337 /**
1338  * parse_tag_3_packet
1339  * @crypt_stat: The cryptographic context to modify based on packet
1340  *              contents.
1341  * @data: The raw bytes of the packet.
1342  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1343  *                 a new authentication token will be placed at the end
1344  *                 of this list for this packet.
1345  * @new_auth_tok: Pointer to a pointer to memory that this function
1346  *                allocates; sets the memory address of the pointer to
1347  *                NULL on error. This object is added to the
1348  *                auth_tok_list.
1349  * @packet_size: This function writes the size of the parsed packet
1350  *               into this memory location; zero on error.
1351  * @max_packet_size: maximum number of bytes to parse
1352  *
1353  * Returns zero on success; non-zero on error.
1354  */
1355 static int
1356 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1357                    unsigned char *data, struct list_head *auth_tok_list,
1358                    struct ecryptfs_auth_tok **new_auth_tok,
1359                    size_t *packet_size, size_t max_packet_size)
1360 {
1361         size_t body_size;
1362         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1363         size_t length_size;
1364         int rc = 0;
1365 
1366         (*packet_size) = 0;
1367         (*new_auth_tok) = NULL;
1368         /**
1369          *This format is inspired by OpenPGP; see RFC 2440
1370          * packet tag 3
1371          *
1372          * Tag 3 identifier (1 byte)
1373          * Max Tag 3 packet size (max 3 bytes)
1374          * Version (1 byte)
1375          * Cipher code (1 byte)
1376          * S2K specifier (1 byte)
1377          * Hash identifier (1 byte)
1378          * Salt (ECRYPTFS_SALT_SIZE)
1379          * Hash iterations (1 byte)
1380          * Encrypted key (arbitrary)
1381          *
1382          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1383          */
1384         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1385                 printk(KERN_ERR "Max packet size too large\n");
1386                 rc = -EINVAL;
1387                 goto out;
1388         }
1389         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1390                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1391                        ECRYPTFS_TAG_3_PACKET_TYPE);
1392                 rc = -EINVAL;
1393                 goto out;
1394         }
1395         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1396          * at end of function upon failure */
1397         auth_tok_list_item =
1398             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1399         if (!auth_tok_list_item) {
1400                 printk(KERN_ERR "Unable to allocate memory\n");
1401                 rc = -ENOMEM;
1402                 goto out;
1403         }
1404         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1405         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1406                                           &length_size);
1407         if (rc) {
1408                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1409                        rc);
1410                 goto out_free;
1411         }
1412         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1413                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1414                 rc = -EINVAL;
1415                 goto out_free;
1416         }
1417         (*packet_size) += length_size;
1418         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1419                 printk(KERN_ERR "Packet size exceeds max\n");
1420                 rc = -EINVAL;
1421                 goto out_free;
1422         }
1423         (*new_auth_tok)->session_key.encrypted_key_size =
1424                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1425         if ((*new_auth_tok)->session_key.encrypted_key_size
1426             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1427                 printk(KERN_WARNING "Tag 3 packet contains key larger "
1428                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1429                 rc = -EINVAL;
1430                 goto out_free;
1431         }
1432         if (unlikely(data[(*packet_size)++] != 0x04)) {
1433                 printk(KERN_WARNING "Unknown version number [%d]\n",
1434                        data[(*packet_size) - 1]);
1435                 rc = -EINVAL;
1436                 goto out_free;
1437         }
1438         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1439                                             (u16)data[(*packet_size)]);
1440         if (rc)
1441                 goto out_free;
1442         /* A little extra work to differentiate among the AES key
1443          * sizes; see RFC2440 */
1444         switch(data[(*packet_size)++]) {
1445         case RFC2440_CIPHER_AES_192:
1446                 crypt_stat->key_size = 24;
1447                 break;
1448         default:
1449                 crypt_stat->key_size =
1450                         (*new_auth_tok)->session_key.encrypted_key_size;
1451         }
1452         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1453         if (rc)
1454                 goto out_free;
1455         if (unlikely(data[(*packet_size)++] != 0x03)) {
1456                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1457                 rc = -ENOSYS;
1458                 goto out_free;
1459         }
1460         /* TODO: finish the hash mapping */
1461         switch (data[(*packet_size)++]) {
1462         case 0x01: /* See RFC2440 for these numbers and their mappings */
1463                 /* Choose MD5 */
1464                 memcpy((*new_auth_tok)->token.password.salt,
1465                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1466                 (*packet_size) += ECRYPTFS_SALT_SIZE;
1467                 /* This conversion was taken straight from RFC2440 */
1468                 (*new_auth_tok)->token.password.hash_iterations =
1469                         ((u32) 16 + (data[(*packet_size)] & 15))
1470                                 << ((data[(*packet_size)] >> 4) + 6);
1471                 (*packet_size)++;
1472                 /* Friendly reminder:
1473                  * (*new_auth_tok)->session_key.encrypted_key_size =
1474                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1475                 memcpy((*new_auth_tok)->session_key.encrypted_key,
1476                        &data[(*packet_size)],
1477                        (*new_auth_tok)->session_key.encrypted_key_size);
1478                 (*packet_size) +=
1479                         (*new_auth_tok)->session_key.encrypted_key_size;
1480                 (*new_auth_tok)->session_key.flags &=
1481                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1482                 (*new_auth_tok)->session_key.flags |=
1483                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1484                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1485                 break;
1486         default:
1487                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1488                                 "[%d]\n", data[(*packet_size) - 1]);
1489                 rc = -ENOSYS;
1490                 goto out_free;
1491         }
1492         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1493         /* TODO: Parametarize; we might actually want userspace to
1494          * decrypt the session key. */
1495         (*new_auth_tok)->session_key.flags &=
1496                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1497         (*new_auth_tok)->session_key.flags &=
1498                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1499         list_add(&auth_tok_list_item->list, auth_tok_list);
1500         goto out;
1501 out_free:
1502         (*new_auth_tok) = NULL;
1503         memset(auth_tok_list_item, 0,
1504                sizeof(struct ecryptfs_auth_tok_list_item));
1505         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1506                         auth_tok_list_item);
1507 out:
1508         if (rc)
1509                 (*packet_size) = 0;
1510         return rc;
1511 }
1512 
1513 /**
1514  * parse_tag_11_packet
1515  * @data: The raw bytes of the packet
1516  * @contents: This function writes the data contents of the literal
1517  *            packet into this memory location
1518  * @max_contents_bytes: The maximum number of bytes that this function
1519  *                      is allowed to write into contents
1520  * @tag_11_contents_size: This function writes the size of the parsed
1521  *                        contents into this memory location; zero on
1522  *                        error
1523  * @packet_size: This function writes the size of the parsed packet
1524  *               into this memory location; zero on error
1525  * @max_packet_size: maximum number of bytes to parse
1526  *
1527  * Returns zero on success; non-zero on error.
1528  */
1529 static int
1530 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1531                     size_t max_contents_bytes, size_t *tag_11_contents_size,
1532                     size_t *packet_size, size_t max_packet_size)
1533 {
1534         size_t body_size;
1535         size_t length_size;
1536         int rc = 0;
1537 
1538         (*packet_size) = 0;
1539         (*tag_11_contents_size) = 0;
1540         /* This format is inspired by OpenPGP; see RFC 2440
1541          * packet tag 11
1542          *
1543          * Tag 11 identifier (1 byte)
1544          * Max Tag 11 packet size (max 3 bytes)
1545          * Binary format specifier (1 byte)
1546          * Filename length (1 byte)
1547          * Filename ("_CONSOLE") (8 bytes)
1548          * Modification date (4 bytes)
1549          * Literal data (arbitrary)
1550          *
1551          * We need at least 16 bytes of data for the packet to even be
1552          * valid.
1553          */
1554         if (max_packet_size < 16) {
1555                 printk(KERN_ERR "Maximum packet size too small\n");
1556                 rc = -EINVAL;
1557                 goto out;
1558         }
1559         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1560                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1561                 rc = -EINVAL;
1562                 goto out;
1563         }
1564         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1565                                           &length_size);
1566         if (rc) {
1567                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1568                 goto out;
1569         }
1570         if (body_size < 14) {
1571                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1572                 rc = -EINVAL;
1573                 goto out;
1574         }
1575         (*packet_size) += length_size;
1576         (*tag_11_contents_size) = (body_size - 14);
1577         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1578                 printk(KERN_ERR "Packet size exceeds max\n");
1579                 rc = -EINVAL;
1580                 goto out;
1581         }
1582         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1583                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1584                        "expected size\n");
1585                 rc = -EINVAL;
1586                 goto out;
1587         }
1588         if (data[(*packet_size)++] != 0x62) {
1589                 printk(KERN_WARNING "Unrecognizable packet\n");
1590                 rc = -EINVAL;
1591                 goto out;
1592         }
1593         if (data[(*packet_size)++] != 0x08) {
1594                 printk(KERN_WARNING "Unrecognizable packet\n");
1595                 rc = -EINVAL;
1596                 goto out;
1597         }
1598         (*packet_size) += 12; /* Ignore filename and modification date */
1599         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1600         (*packet_size) += (*tag_11_contents_size);
1601 out:
1602         if (rc) {
1603                 (*packet_size) = 0;
1604                 (*tag_11_contents_size) = 0;
1605         }
1606         return rc;
1607 }
1608 
1609 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1610                                       struct ecryptfs_auth_tok **auth_tok,
1611                                       char *sig)
1612 {
1613         int rc = 0;
1614 
1615         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1616         if (IS_ERR(*auth_tok_key)) {
1617                 (*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
1618                 if (IS_ERR(*auth_tok_key)) {
1619                         printk(KERN_ERR "Could not find key with description: [%s]\n",
1620                               sig);
1621                         rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1622                         (*auth_tok_key) = NULL;
1623                         goto out;
1624                 }
1625         }
1626         down_write(&(*auth_tok_key)->sem);
1627         rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1628         if (rc) {
1629                 up_write(&(*auth_tok_key)->sem);
1630                 key_put(*auth_tok_key);
1631                 (*auth_tok_key) = NULL;
1632                 goto out;
1633         }
1634 out:
1635         return rc;
1636 }
1637 
1638 /**
1639  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1640  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1641  * @crypt_stat: The cryptographic context
1642  *
1643  * Returns zero on success; non-zero error otherwise
1644  */
1645 static int
1646 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1647                                          struct ecryptfs_crypt_stat *crypt_stat)
1648 {
1649         struct scatterlist dst_sg[2];
1650         struct scatterlist src_sg[2];
1651         struct mutex *tfm_mutex;
1652         struct crypto_skcipher *tfm;
1653         struct skcipher_request *req = NULL;
1654         int rc = 0;
1655 
1656         if (unlikely(ecryptfs_verbosity > 0)) {
1657                 ecryptfs_printk(
1658                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1659                         auth_tok->token.password.session_key_encryption_key_bytes);
1660                 ecryptfs_dump_hex(
1661                         auth_tok->token.password.session_key_encryption_key,
1662                         auth_tok->token.password.session_key_encryption_key_bytes);
1663         }
1664         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
1665                                                         crypt_stat->cipher);
1666         if (unlikely(rc)) {
1667                 printk(KERN_ERR "Internal error whilst attempting to get "
1668                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1669                        crypt_stat->cipher, rc);
1670                 goto out;
1671         }
1672         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1673                                  auth_tok->session_key.encrypted_key_size,
1674                                  src_sg, 2);
1675         if (rc < 1 || rc > 2) {
1676                 printk(KERN_ERR "Internal error whilst attempting to convert "
1677                         "auth_tok->session_key.encrypted_key to scatterlist; "
1678                         "expected rc = 1; got rc = [%d]. "
1679                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1680                         auth_tok->session_key.encrypted_key_size);
1681                 goto out;
1682         }
1683         auth_tok->session_key.decrypted_key_size =
1684                 auth_tok->session_key.encrypted_key_size;
1685         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1686                                  auth_tok->session_key.decrypted_key_size,
1687                                  dst_sg, 2);
1688         if (rc < 1 || rc > 2) {
1689                 printk(KERN_ERR "Internal error whilst attempting to convert "
1690                         "auth_tok->session_key.decrypted_key to scatterlist; "
1691                         "expected rc = 1; got rc = [%d]\n", rc);
1692                 goto out;
1693         }
1694         mutex_lock(tfm_mutex);
1695         req = skcipher_request_alloc(tfm, GFP_KERNEL);
1696         if (!req) {
1697                 mutex_unlock(tfm_mutex);
1698                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
1699                        "skcipher_request_alloc for %s\n", __func__,
1700                        crypto_skcipher_driver_name(tfm));
1701                 rc = -ENOMEM;
1702                 goto out;
1703         }
1704 
1705         skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
1706                                       NULL, NULL);
1707         rc = crypto_skcipher_setkey(
1708                 tfm, auth_tok->token.password.session_key_encryption_key,
1709                 crypt_stat->key_size);
1710         if (unlikely(rc < 0)) {
1711                 mutex_unlock(tfm_mutex);
1712                 printk(KERN_ERR "Error setting key for crypto context\n");
1713                 rc = -EINVAL;
1714                 goto out;
1715         }
1716         skcipher_request_set_crypt(req, src_sg, dst_sg,
1717                                    auth_tok->session_key.encrypted_key_size,
1718                                    NULL);
1719         rc = crypto_skcipher_decrypt(req);
1720         mutex_unlock(tfm_mutex);
1721         if (unlikely(rc)) {
1722                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1723                 goto out;
1724         }
1725         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1726         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1727                auth_tok->session_key.decrypted_key_size);
1728         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1729         if (unlikely(ecryptfs_verbosity > 0)) {
1730                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1731                                 crypt_stat->key_size);
1732                 ecryptfs_dump_hex(crypt_stat->key,
1733                                   crypt_stat->key_size);
1734         }
1735 out:
1736         skcipher_request_free(req);
1737         return rc;
1738 }
1739 
1740 /**
1741  * ecryptfs_parse_packet_set
1742  * @crypt_stat: The cryptographic context
1743  * @src: Virtual address of region of memory containing the packets
1744  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1745  *
1746  * Get crypt_stat to have the file's session key if the requisite key
1747  * is available to decrypt the session key.
1748  *
1749  * Returns Zero if a valid authentication token was retrieved and
1750  * processed; negative value for file not encrypted or for error
1751  * conditions.
1752  */
1753 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1754                               unsigned char *src,
1755                               struct dentry *ecryptfs_dentry)
1756 {
1757         size_t i = 0;
1758         size_t found_auth_tok;
1759         size_t next_packet_is_auth_tok_packet;
1760         struct list_head auth_tok_list;
1761         struct ecryptfs_auth_tok *matching_auth_tok;
1762         struct ecryptfs_auth_tok *candidate_auth_tok;
1763         char *candidate_auth_tok_sig;
1764         size_t packet_size;
1765         struct ecryptfs_auth_tok *new_auth_tok;
1766         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1767         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1768         size_t tag_11_contents_size;
1769         size_t tag_11_packet_size;
1770         struct key *auth_tok_key = NULL;
1771         int rc = 0;
1772 
1773         INIT_LIST_HEAD(&auth_tok_list);
1774         /* Parse the header to find as many packets as we can; these will be
1775          * added the our &auth_tok_list */
1776         next_packet_is_auth_tok_packet = 1;
1777         while (next_packet_is_auth_tok_packet) {
1778                 size_t max_packet_size = ((PAGE_SIZE - 8) - i);
1779 
1780                 switch (src[i]) {
1781                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1782                         rc = parse_tag_3_packet(crypt_stat,
1783                                                 (unsigned char *)&src[i],
1784                                                 &auth_tok_list, &new_auth_tok,
1785                                                 &packet_size, max_packet_size);
1786                         if (rc) {
1787                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1788                                                 "tag 3 packet\n");
1789                                 rc = -EIO;
1790                                 goto out_wipe_list;
1791                         }
1792                         i += packet_size;
1793                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1794                                                  sig_tmp_space,
1795                                                  ECRYPTFS_SIG_SIZE,
1796                                                  &tag_11_contents_size,
1797                                                  &tag_11_packet_size,
1798                                                  max_packet_size);
1799                         if (rc) {
1800                                 ecryptfs_printk(KERN_ERR, "No valid "
1801                                                 "(ecryptfs-specific) literal "
1802                                                 "packet containing "
1803                                                 "authentication token "
1804                                                 "signature found after "
1805                                                 "tag 3 packet\n");
1806                                 rc = -EIO;
1807                                 goto out_wipe_list;
1808                         }
1809                         i += tag_11_packet_size;
1810                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1811                                 ecryptfs_printk(KERN_ERR, "Expected "
1812                                                 "signature of size [%d]; "
1813                                                 "read size [%zd]\n",
1814                                                 ECRYPTFS_SIG_SIZE,
1815                                                 tag_11_contents_size);
1816                                 rc = -EIO;
1817                                 goto out_wipe_list;
1818                         }
1819                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1820                                         sig_tmp_space, tag_11_contents_size);
1821                         new_auth_tok->token.password.signature[
1822                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1823                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1824                         break;
1825                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1826                         rc = parse_tag_1_packet(crypt_stat,
1827                                                 (unsigned char *)&src[i],
1828                                                 &auth_tok_list, &new_auth_tok,
1829                                                 &packet_size, max_packet_size);
1830                         if (rc) {
1831                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1832                                                 "tag 1 packet\n");
1833                                 rc = -EIO;
1834                                 goto out_wipe_list;
1835                         }
1836                         i += packet_size;
1837                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1838                         break;
1839                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1840                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1841                                         "(Tag 11 not allowed by itself)\n");
1842                         rc = -EIO;
1843                         goto out_wipe_list;
1844                 default:
1845                         ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1846                                         "of the file header; hex value of "
1847                                         "character is [0x%.2x]\n", i, src[i]);
1848                         next_packet_is_auth_tok_packet = 0;
1849                 }
1850         }
1851         if (list_empty(&auth_tok_list)) {
1852                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1853                        "eCryptfs file; this is not supported in this version "
1854                        "of the eCryptfs kernel module\n");
1855                 rc = -EINVAL;
1856                 goto out;
1857         }
1858         /* auth_tok_list contains the set of authentication tokens
1859          * parsed from the metadata. We need to find a matching
1860          * authentication token that has the secret component(s)
1861          * necessary to decrypt the EFEK in the auth_tok parsed from
1862          * the metadata. There may be several potential matches, but
1863          * just one will be sufficient to decrypt to get the FEK. */
1864 find_next_matching_auth_tok:
1865         found_auth_tok = 0;
1866         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1867                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1868                 if (unlikely(ecryptfs_verbosity > 0)) {
1869                         ecryptfs_printk(KERN_DEBUG,
1870                                         "Considering candidate auth tok:\n");
1871                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1872                 }
1873                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1874                                                candidate_auth_tok);
1875                 if (rc) {
1876                         printk(KERN_ERR
1877                                "Unrecognized candidate auth tok type: [%d]\n",
1878                                candidate_auth_tok->token_type);
1879                         rc = -EINVAL;
1880                         goto out_wipe_list;
1881                 }
1882                 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1883                                                &matching_auth_tok,
1884                                                crypt_stat->mount_crypt_stat,
1885                                                candidate_auth_tok_sig);
1886                 if (!rc) {
1887                         found_auth_tok = 1;
1888                         goto found_matching_auth_tok;
1889                 }
1890         }
1891         if (!found_auth_tok) {
1892                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1893                                 "authentication token\n");
1894                 rc = -EIO;
1895                 goto out_wipe_list;
1896         }
1897 found_matching_auth_tok:
1898         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1899                 memcpy(&(candidate_auth_tok->token.private_key),
1900                        &(matching_auth_tok->token.private_key),
1901                        sizeof(struct ecryptfs_private_key));
1902                 up_write(&(auth_tok_key->sem));
1903                 key_put(auth_tok_key);
1904                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1905                                                        crypt_stat);
1906         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1907                 memcpy(&(candidate_auth_tok->token.password),
1908                        &(matching_auth_tok->token.password),
1909                        sizeof(struct ecryptfs_password));
1910                 up_write(&(auth_tok_key->sem));
1911                 key_put(auth_tok_key);
1912                 rc = decrypt_passphrase_encrypted_session_key(
1913                         candidate_auth_tok, crypt_stat);
1914         } else {
1915                 up_write(&(auth_tok_key->sem));
1916                 key_put(auth_tok_key);
1917                 rc = -EINVAL;
1918         }
1919         if (rc) {
1920                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1921 
1922                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1923                                 "session key for authentication token with sig "
1924                                 "[%.*s]; rc = [%d]. Removing auth tok "
1925                                 "candidate from the list and searching for "
1926                                 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1927                                 candidate_auth_tok_sig, rc);
1928                 list_for_each_entry_safe(auth_tok_list_item,
1929                                          auth_tok_list_item_tmp,
1930                                          &auth_tok_list, list) {
1931                         if (candidate_auth_tok
1932                             == &auth_tok_list_item->auth_tok) {
1933                                 list_del(&auth_tok_list_item->list);
1934                                 kmem_cache_free(
1935                                         ecryptfs_auth_tok_list_item_cache,
1936                                         auth_tok_list_item);
1937                                 goto find_next_matching_auth_tok;
1938                         }
1939                 }
1940                 BUG();
1941         }
1942         rc = ecryptfs_compute_root_iv(crypt_stat);
1943         if (rc) {
1944                 ecryptfs_printk(KERN_ERR, "Error computing "
1945                                 "the root IV\n");
1946                 goto out_wipe_list;
1947         }
1948         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1949         if (rc) {
1950                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1951                                 "context for cipher [%s]; rc = [%d]\n",
1952                                 crypt_stat->cipher, rc);
1953         }
1954 out_wipe_list:
1955         wipe_auth_tok_list(&auth_tok_list);
1956 out:
1957         return rc;
1958 }
1959 
1960 static int
1961 pki_encrypt_session_key(struct key *auth_tok_key,
1962                         struct ecryptfs_auth_tok *auth_tok,
1963                         struct ecryptfs_crypt_stat *crypt_stat,
1964                         struct ecryptfs_key_record *key_rec)
1965 {
1966         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1967         char *payload = NULL;
1968         size_t payload_len = 0;
1969         struct ecryptfs_message *msg;
1970         int rc;
1971 
1972         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1973                                  ecryptfs_code_for_cipher_string(
1974                                          crypt_stat->cipher,
1975                                          crypt_stat->key_size),
1976                                  crypt_stat, &payload, &payload_len);
1977         up_write(&(auth_tok_key->sem));
1978         key_put(auth_tok_key);
1979         if (rc) {
1980                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1981                 goto out;
1982         }
1983         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1984         if (rc) {
1985                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1986                                 "ecryptfsd: %d\n", rc);
1987                 goto out;
1988         }
1989         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1990         if (rc) {
1991                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1992                                 "from the user space daemon\n");
1993                 rc = -EIO;
1994                 goto out;
1995         }
1996         rc = parse_tag_67_packet(key_rec, msg);
1997         if (rc)
1998                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
1999         kfree(msg);
2000 out:
2001         kfree(payload);
2002         return rc;
2003 }
2004 /**
2005  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2006  * @dest: Buffer into which to write the packet
2007  * @remaining_bytes: Maximum number of bytes that can be writtn
2008  * @auth_tok_key: The authentication token key to unlock and put when done with
2009  *                @auth_tok
2010  * @auth_tok: The authentication token used for generating the tag 1 packet
2011  * @crypt_stat: The cryptographic context
2012  * @key_rec: The key record struct for the tag 1 packet
2013  * @packet_size: This function will write the number of bytes that end
2014  *               up constituting the packet; set to zero on error
2015  *
2016  * Returns zero on success; non-zero on error.
2017  */
2018 static int
2019 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2020                    struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
2021                    struct ecryptfs_crypt_stat *crypt_stat,
2022                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2023 {
2024         size_t i;
2025         size_t encrypted_session_key_valid = 0;
2026         size_t packet_size_length;
2027         size_t max_packet_size;
2028         int rc = 0;
2029 
2030         (*packet_size) = 0;
2031         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2032                           ECRYPTFS_SIG_SIZE);
2033         encrypted_session_key_valid = 0;
2034         for (i = 0; i < crypt_stat->key_size; i++)
2035                 encrypted_session_key_valid |=
2036                         auth_tok->session_key.encrypted_key[i];
2037         if (encrypted_session_key_valid) {
2038                 memcpy(key_rec->enc_key,
2039                        auth_tok->session_key.encrypted_key,
2040                        auth_tok->session_key.encrypted_key_size);
2041                 up_write(&(auth_tok_key->sem));
2042                 key_put(auth_tok_key);
2043                 goto encrypted_session_key_set;
2044         }
2045         if (auth_tok->session_key.encrypted_key_size == 0)
2046                 auth_tok->session_key.encrypted_key_size =
2047                         auth_tok->token.private_key.key_size;
2048         rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
2049                                      key_rec);
2050         if (rc) {
2051                 printk(KERN_ERR "Failed to encrypt session key via a key "
2052                        "module; rc = [%d]\n", rc);
2053                 goto out;
2054         }
2055         if (ecryptfs_verbosity > 0) {
2056                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2057                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2058         }
2059 encrypted_session_key_set:
2060         /* This format is inspired by OpenPGP; see RFC 2440
2061          * packet tag 1 */
2062         max_packet_size = (1                         /* Tag 1 identifier */
2063                            + 3                       /* Max Tag 1 packet size */
2064                            + 1                       /* Version */
2065                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
2066                            + 1                       /* Cipher identifier */
2067                            + key_rec->enc_key_size); /* Encrypted key size */
2068         if (max_packet_size > (*remaining_bytes)) {
2069                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2070                        "need up to [%td] bytes, but there are only [%td] "
2071                        "available\n", max_packet_size, (*remaining_bytes));
2072                 rc = -EINVAL;
2073                 goto out;
2074         }
2075         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2076         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2077                                           (max_packet_size - 4),
2078                                           &packet_size_length);
2079         if (rc) {
2080                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2081                                 "header; cannot generate packet length\n");
2082                 goto out;
2083         }
2084         (*packet_size) += packet_size_length;
2085         dest[(*packet_size)++] = 0x03; /* version 3 */
2086         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2087         (*packet_size) += ECRYPTFS_SIG_SIZE;
2088         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2089         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2090                key_rec->enc_key_size);
2091         (*packet_size) += key_rec->enc_key_size;
2092 out:
2093         if (rc)
2094                 (*packet_size) = 0;
2095         else
2096                 (*remaining_bytes) -= (*packet_size);
2097         return rc;
2098 }
2099 
2100 /**
2101  * write_tag_11_packet
2102  * @dest: Target into which Tag 11 packet is to be written
2103  * @remaining_bytes: Maximum packet length
2104  * @contents: Byte array of contents to copy in
2105  * @contents_length: Number of bytes in contents
2106  * @packet_length: Length of the Tag 11 packet written; zero on error
2107  *
2108  * Returns zero on success; non-zero on error.
2109  */
2110 static int
2111 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2112                     size_t contents_length, size_t *packet_length)
2113 {
2114         size_t packet_size_length;
2115         size_t max_packet_size;
2116         int rc = 0;
2117 
2118         (*packet_length) = 0;
2119         /* This format is inspired by OpenPGP; see RFC 2440
2120          * packet tag 11 */
2121         max_packet_size = (1                   /* Tag 11 identifier */
2122                            + 3                 /* Max Tag 11 packet size */
2123                            + 1                 /* Binary format specifier */
2124                            + 1                 /* Filename length */
2125                            + 8                 /* Filename ("_CONSOLE") */
2126                            + 4                 /* Modification date */
2127                            + contents_length); /* Literal data */
2128         if (max_packet_size > (*remaining_bytes)) {
2129                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2130                        "need up to [%td] bytes, but there are only [%td] "
2131                        "available\n", max_packet_size, (*remaining_bytes));
2132                 rc = -EINVAL;
2133                 goto out;
2134         }
2135         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2136         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2137                                           (max_packet_size - 4),
2138                                           &packet_size_length);
2139         if (rc) {
2140                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2141                        "generate packet length. rc = [%d]\n", rc);
2142                 goto out;
2143         }
2144         (*packet_length) += packet_size_length;
2145         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2146         dest[(*packet_length)++] = 8;
2147         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2148         (*packet_length) += 8;
2149         memset(&dest[(*packet_length)], 0x00, 4);
2150         (*packet_length) += 4;
2151         memcpy(&dest[(*packet_length)], contents, contents_length);
2152         (*packet_length) += contents_length;
2153  out:
2154         if (rc)
2155                 (*packet_length) = 0;
2156         else
2157                 (*remaining_bytes) -= (*packet_length);
2158         return rc;
2159 }
2160 
2161 /**
2162  * write_tag_3_packet
2163  * @dest: Buffer into which to write the packet
2164  * @remaining_bytes: Maximum number of bytes that can be written
2165  * @auth_tok: Authentication token
2166  * @crypt_stat: The cryptographic context
2167  * @key_rec: encrypted key
2168  * @packet_size: This function will write the number of bytes that end
2169  *               up constituting the packet; set to zero on error
2170  *
2171  * Returns zero on success; non-zero on error.
2172  */
2173 static int
2174 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2175                    struct ecryptfs_auth_tok *auth_tok,
2176                    struct ecryptfs_crypt_stat *crypt_stat,
2177                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2178 {
2179         size_t i;
2180         size_t encrypted_session_key_valid = 0;
2181         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2182         struct scatterlist dst_sg[2];
2183         struct scatterlist src_sg[2];
2184         struct mutex *tfm_mutex = NULL;
2185         u8 cipher_code;
2186         size_t packet_size_length;
2187         size_t max_packet_size;
2188         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2189                 crypt_stat->mount_crypt_stat;
2190         struct crypto_skcipher *tfm;
2191         struct skcipher_request *req;
2192         int rc = 0;
2193 
2194         (*packet_size) = 0;
2195         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2196                           ECRYPTFS_SIG_SIZE);
2197         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2198                                                         crypt_stat->cipher);
2199         if (unlikely(rc)) {
2200                 printk(KERN_ERR "Internal error whilst attempting to get "
2201                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2202                        crypt_stat->cipher, rc);
2203                 goto out;
2204         }
2205         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2206                 printk(KERN_WARNING "No key size specified at mount; "
2207                        "defaulting to [%d]\n",
2208                        crypto_skcipher_max_keysize(tfm));
2209                 mount_crypt_stat->global_default_cipher_key_size =
2210                         crypto_skcipher_max_keysize(tfm);
2211         }
2212         if (crypt_stat->key_size == 0)
2213                 crypt_stat->key_size =
2214                         mount_crypt_stat->global_default_cipher_key_size;
2215         if (auth_tok->session_key.encrypted_key_size == 0)
2216                 auth_tok->session_key.encrypted_key_size =
2217                         crypt_stat->key_size;
2218         if (crypt_stat->key_size == 24
2219             && strcmp("aes", crypt_stat->cipher) == 0) {
2220                 memset((crypt_stat->key + 24), 0, 8);
2221                 auth_tok->session_key.encrypted_key_size = 32;
2222         } else
2223                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2224         key_rec->enc_key_size =
2225                 auth_tok->session_key.encrypted_key_size;
2226         encrypted_session_key_valid = 0;
2227         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2228                 encrypted_session_key_valid |=
2229                         auth_tok->session_key.encrypted_key[i];
2230         if (encrypted_session_key_valid) {
2231                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2232                                 "using auth_tok->session_key.encrypted_key, "
2233                                 "where key_rec->enc_key_size = [%zd]\n",
2234                                 key_rec->enc_key_size);
2235                 memcpy(key_rec->enc_key,
2236                        auth_tok->session_key.encrypted_key,
2237                        key_rec->enc_key_size);
2238                 goto encrypted_session_key_set;
2239         }
2240         if (auth_tok->token.password.flags &
2241             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2242                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2243                                 "session key encryption key of size [%d]\n",
2244                                 auth_tok->token.password.
2245                                 session_key_encryption_key_bytes);
2246                 memcpy(session_key_encryption_key,
2247                        auth_tok->token.password.session_key_encryption_key,
2248                        crypt_stat->key_size);
2249                 ecryptfs_printk(KERN_DEBUG,
2250                                 "Cached session key encryption key:\n");
2251                 if (ecryptfs_verbosity > 0)
2252                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2253         }
2254         if (unlikely(ecryptfs_verbosity > 0)) {
2255                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2256                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2257         }
2258         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2259                                  src_sg, 2);
2260         if (rc < 1 || rc > 2) {
2261                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2262                                 "for crypt_stat session key; expected rc = 1; "
2263                                 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2264                                 rc, key_rec->enc_key_size);
2265                 rc = -ENOMEM;
2266                 goto out;
2267         }
2268         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2269                                  dst_sg, 2);
2270         if (rc < 1 || rc > 2) {
2271                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2272                                 "for crypt_stat encrypted session key; "
2273                                 "expected rc = 1; got rc = [%d]. "
2274                                 "key_rec->enc_key_size = [%zd]\n", rc,
2275                                 key_rec->enc_key_size);
2276                 rc = -ENOMEM;
2277                 goto out;
2278         }
2279         mutex_lock(tfm_mutex);
2280         rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
2281                                     crypt_stat->key_size);
2282         if (rc < 0) {
2283                 mutex_unlock(tfm_mutex);
2284                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2285                                 "context; rc = [%d]\n", rc);
2286                 goto out;
2287         }
2288 
2289         req = skcipher_request_alloc(tfm, GFP_KERNEL);
2290         if (!req) {
2291                 mutex_unlock(tfm_mutex);
2292                 ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
2293                                 "attempting to skcipher_request_alloc for "
2294                                 "%s\n", crypto_skcipher_driver_name(tfm));
2295                 rc = -ENOMEM;
2296                 goto out;
2297         }
2298 
2299         skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
2300                                       NULL, NULL);
2301 
2302         rc = 0;
2303         ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2304                         crypt_stat->key_size);
2305         skcipher_request_set_crypt(req, src_sg, dst_sg,
2306                                    (*key_rec).enc_key_size, NULL);
2307         rc = crypto_skcipher_encrypt(req);
2308         mutex_unlock(tfm_mutex);
2309         skcipher_request_free(req);
2310         if (rc) {
2311                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2312                 goto out;
2313         }
2314         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2315         if (ecryptfs_verbosity > 0) {
2316                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2317                                 key_rec->enc_key_size);
2318                 ecryptfs_dump_hex(key_rec->enc_key,
2319                                   key_rec->enc_key_size);
2320         }
2321 encrypted_session_key_set:
2322         /* This format is inspired by OpenPGP; see RFC 2440
2323          * packet tag 3 */
2324         max_packet_size = (1                         /* Tag 3 identifier */
2325                            + 3                       /* Max Tag 3 packet size */
2326                            + 1                       /* Version */
2327                            + 1                       /* Cipher code */
2328                            + 1                       /* S2K specifier */
2329                            + 1                       /* Hash identifier */
2330                            + ECRYPTFS_SALT_SIZE      /* Salt */
2331                            + 1                       /* Hash iterations */
2332                            + key_rec->enc_key_size); /* Encrypted key size */
2333         if (max_packet_size > (*remaining_bytes)) {
2334                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2335                        "there are only [%td] available\n", max_packet_size,
2336                        (*remaining_bytes));
2337                 rc = -EINVAL;
2338                 goto out;
2339         }
2340         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2341         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2342          * to get the number of octets in the actual Tag 3 packet */
2343         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2344                                           (max_packet_size - 4),
2345                                           &packet_size_length);
2346         if (rc) {
2347                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2348                        "generate packet length. rc = [%d]\n", rc);
2349                 goto out;
2350         }
2351         (*packet_size) += packet_size_length;
2352         dest[(*packet_size)++] = 0x04; /* version 4 */
2353         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2354          * specified with strings */
2355         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2356                                                       crypt_stat->key_size);
2357         if (cipher_code == 0) {
2358                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2359                                 "cipher [%s]\n", crypt_stat->cipher);
2360                 rc = -EINVAL;
2361                 goto out;
2362         }
2363         dest[(*packet_size)++] = cipher_code;
2364         dest[(*packet_size)++] = 0x03;  /* S2K */
2365         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2366         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2367                ECRYPTFS_SALT_SIZE);
2368         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2369         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2370         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2371                key_rec->enc_key_size);
2372         (*packet_size) += key_rec->enc_key_size;
2373 out:
2374         if (rc)
2375                 (*packet_size) = 0;
2376         else
2377                 (*remaining_bytes) -= (*packet_size);
2378         return rc;
2379 }
2380 
2381 struct kmem_cache *ecryptfs_key_record_cache;
2382 
2383 /**
2384  * ecryptfs_generate_key_packet_set
2385  * @dest_base: Virtual address from which to write the key record set
2386  * @crypt_stat: The cryptographic context from which the
2387  *              authentication tokens will be retrieved
2388  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2389  *                   for the global parameters
2390  * @len: The amount written
2391  * @max: The maximum amount of data allowed to be written
2392  *
2393  * Generates a key packet set and writes it to the virtual address
2394  * passed in.
2395  *
2396  * Returns zero on success; non-zero on error.
2397  */
2398 int
2399 ecryptfs_generate_key_packet_set(char *dest_base,
2400                                  struct ecryptfs_crypt_stat *crypt_stat,
2401                                  struct dentry *ecryptfs_dentry, size_t *len,
2402                                  size_t max)
2403 {
2404         struct ecryptfs_auth_tok *auth_tok;
2405         struct key *auth_tok_key = NULL;
2406         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2407                 &ecryptfs_superblock_to_private(
2408                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2409         size_t written;
2410         struct ecryptfs_key_record *key_rec;
2411         struct ecryptfs_key_sig *key_sig;
2412         int rc = 0;
2413 
2414         (*len) = 0;
2415         mutex_lock(&crypt_stat->keysig_list_mutex);
2416         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2417         if (!key_rec) {
2418                 rc = -ENOMEM;
2419                 goto out;
2420         }
2421         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2422                             crypt_stat_list) {
2423                 memset(key_rec, 0, sizeof(*key_rec));
2424                 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2425                                                            &auth_tok,
2426                                                            mount_crypt_stat,
2427                                                            key_sig->keysig);
2428                 if (rc) {
2429                         printk(KERN_WARNING "Unable to retrieve auth tok with "
2430                                "sig = [%s]\n", key_sig->keysig);
2431                         rc = process_find_global_auth_tok_for_sig_err(rc);
2432                         goto out_free;
2433                 }
2434                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2435                         rc = write_tag_3_packet((dest_base + (*len)),
2436                                                 &max, auth_tok,
2437                                                 crypt_stat, key_rec,
2438                                                 &written);
2439                         up_write(&(auth_tok_key->sem));
2440                         key_put(auth_tok_key);
2441                         if (rc) {
2442                                 ecryptfs_printk(KERN_WARNING, "Error "
2443                                                 "writing tag 3 packet\n");
2444                                 goto out_free;
2445                         }
2446                         (*len) += written;
2447                         /* Write auth tok signature packet */
2448                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2449                                                  key_rec->sig,
2450                                                  ECRYPTFS_SIG_SIZE, &written);
2451                         if (rc) {
2452                                 ecryptfs_printk(KERN_ERR, "Error writing "
2453                                                 "auth tok signature packet\n");
2454                                 goto out_free;
2455                         }
2456                         (*len) += written;
2457                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2458                         rc = write_tag_1_packet(dest_base + (*len), &max,
2459                                                 auth_tok_key, auth_tok,
2460                                                 crypt_stat, key_rec, &written);
2461                         if (rc) {
2462                                 ecryptfs_printk(KERN_WARNING, "Error "
2463                                                 "writing tag 1 packet\n");
2464                                 goto out_free;
2465                         }
2466                         (*len) += written;
2467                 } else {
2468                         up_write(&(auth_tok_key->sem));
2469                         key_put(auth_tok_key);
2470                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2471                                         "authentication token type\n");
2472                         rc = -EINVAL;
2473                         goto out_free;
2474                 }
2475         }
2476         if (likely(max > 0)) {
2477                 dest_base[(*len)] = 0x00;
2478         } else {
2479                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2480                 rc = -EIO;
2481         }
2482 out_free:
2483         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2484 out:
2485         if (rc)
2486                 (*len) = 0;
2487         mutex_unlock(&crypt_stat->keysig_list_mutex);
2488         return rc;
2489 }
2490 
2491 struct kmem_cache *ecryptfs_key_sig_cache;
2492 
2493 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2494 {
2495         struct ecryptfs_key_sig *new_key_sig;
2496 
2497         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2498         if (!new_key_sig)
2499                 return -ENOMEM;
2500 
2501         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2502         new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2503         /* Caller must hold keysig_list_mutex */
2504         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2505 
2506         return 0;
2507 }
2508 
2509 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2510 
2511 int
2512 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2513                              char *sig, u32 global_auth_tok_flags)
2514 {
2515         struct ecryptfs_global_auth_tok *new_auth_tok;
2516 
2517         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2518                                         GFP_KERNEL);
2519         if (!new_auth_tok)
2520                 return -ENOMEM;
2521 
2522         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2523         new_auth_tok->flags = global_auth_tok_flags;
2524         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2525         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2526         list_add(&new_auth_tok->mount_crypt_stat_list,
2527                  &mount_crypt_stat->global_auth_tok_list);
2528         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2529         return 0;
2530 }
2531 
2532 

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