eCryptfs: write lock requested keys
[linux-3.10.git] / fs / ecryptfs / keystore.c
1 /**
2  * eCryptfs: Linux filesystem encryption layer
3  * In-kernel key management code.  Includes functions to parse and
4  * write authentication token-related packets with the underlying
5  * file.
6  *
7  * Copyright (C) 2004-2006 International Business Machines Corp.
8  *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
9  *              Michael C. Thompson <mcthomps@us.ibm.com>
10  *              Trevor S. Highland <trevor.highland@gmail.com>
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License as
14  * published by the Free Software Foundation; either version 2 of the
15  * License, or (at your option) any later version.
16  *
17  * This program is distributed in the hope that it will be useful, but
18  * WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20  * General Public License for more details.
21  *
22  * You should have received a copy of the GNU General Public License
23  * along with this program; if not, write to the Free Software
24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25  * 02111-1307, USA.
26  */
27
28 #include <linux/string.h>
29 #include <linux/syscalls.h>
30 #include <linux/pagemap.h>
31 #include <linux/key.h>
32 #include <linux/random.h>
33 #include <linux/crypto.h>
34 #include <linux/scatterlist.h>
35 #include <linux/slab.h>
36 #include "ecryptfs_kernel.h"
37
38 /**
39  * request_key returned an error instead of a valid key address;
40  * determine the type of error, make appropriate log entries, and
41  * return an error code.
42  */
43 static int process_request_key_err(long err_code)
44 {
45         int rc = 0;
46
47         switch (err_code) {
48         case -ENOKEY:
49                 ecryptfs_printk(KERN_WARNING, "No key\n");
50                 rc = -ENOENT;
51                 break;
52         case -EKEYEXPIRED:
53                 ecryptfs_printk(KERN_WARNING, "Key expired\n");
54                 rc = -ETIME;
55                 break;
56         case -EKEYREVOKED:
57                 ecryptfs_printk(KERN_WARNING, "Key revoked\n");
58                 rc = -EINVAL;
59                 break;
60         default:
61                 ecryptfs_printk(KERN_WARNING, "Unknown error code: "
62                                 "[0x%.16lx]\n", err_code);
63                 rc = -EINVAL;
64         }
65         return rc;
66 }
67
68 static int process_find_global_auth_tok_for_sig_err(int err_code)
69 {
70         int rc = err_code;
71
72         switch (err_code) {
73         case -ENOENT:
74                 ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
75                 break;
76         case -EINVAL:
77                 ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
78                 break;
79         default:
80                 rc = process_request_key_err(err_code);
81                 break;
82         }
83         return rc;
84 }
85
86 /**
87  * ecryptfs_parse_packet_length
88  * @data: Pointer to memory containing length at offset
89  * @size: This function writes the decoded size to this memory
90  *        address; zero on error
91  * @length_size: The number of bytes occupied by the encoded length
92  *
93  * Returns zero on success; non-zero on error
94  */
95 int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
96                                  size_t *length_size)
97 {
98         int rc = 0;
99
100         (*length_size) = 0;
101         (*size) = 0;
102         if (data[0] < 192) {
103                 /* One-byte length */
104                 (*size) = (unsigned char)data[0];
105                 (*length_size) = 1;
106         } else if (data[0] < 224) {
107                 /* Two-byte length */
108                 (*size) = (((unsigned char)(data[0]) - 192) * 256);
109                 (*size) += ((unsigned char)(data[1]) + 192);
110                 (*length_size) = 2;
111         } else if (data[0] == 255) {
112                 /* Five-byte length; we're not supposed to see this */
113                 ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
114                                 "supported\n");
115                 rc = -EINVAL;
116                 goto out;
117         } else {
118                 ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
119                 rc = -EINVAL;
120                 goto out;
121         }
122 out:
123         return rc;
124 }
125
126 /**
127  * ecryptfs_write_packet_length
128  * @dest: The byte array target into which to write the length. Must
129  *        have at least 5 bytes allocated.
130  * @size: The length to write.
131  * @packet_size_length: The number of bytes used to encode the packet
132  *                      length is written to this address.
133  *
134  * Returns zero on success; non-zero on error.
135  */
136 int ecryptfs_write_packet_length(char *dest, size_t size,
137                                  size_t *packet_size_length)
138 {
139         int rc = 0;
140
141         if (size < 192) {
142                 dest[0] = size;
143                 (*packet_size_length) = 1;
144         } else if (size < 65536) {
145                 dest[0] = (((size - 192) / 256) + 192);
146                 dest[1] = ((size - 192) % 256);
147                 (*packet_size_length) = 2;
148         } else {
149                 rc = -EINVAL;
150                 ecryptfs_printk(KERN_WARNING,
151                                 "Unsupported packet size: [%zd]\n", size);
152         }
153         return rc;
154 }
155
156 static int
157 write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
158                     char **packet, size_t *packet_len)
159 {
160         size_t i = 0;
161         size_t data_len;
162         size_t packet_size_len;
163         char *message;
164         int rc;
165
166         /*
167          *              ***** TAG 64 Packet Format *****
168          *    | Content Type                       | 1 byte       |
169          *    | Key Identifier Size                | 1 or 2 bytes |
170          *    | Key Identifier                     | arbitrary    |
171          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
172          *    | Encrypted File Encryption Key      | arbitrary    |
173          */
174         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
175                     + session_key->encrypted_key_size);
176         *packet = kmalloc(data_len, GFP_KERNEL);
177         message = *packet;
178         if (!message) {
179                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
180                 rc = -ENOMEM;
181                 goto out;
182         }
183         message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
184         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
185                                           &packet_size_len);
186         if (rc) {
187                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
188                                 "header; cannot generate packet length\n");
189                 goto out;
190         }
191         i += packet_size_len;
192         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
193         i += ECRYPTFS_SIG_SIZE_HEX;
194         rc = ecryptfs_write_packet_length(&message[i],
195                                           session_key->encrypted_key_size,
196                                           &packet_size_len);
197         if (rc) {
198                 ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
199                                 "header; cannot generate packet length\n");
200                 goto out;
201         }
202         i += packet_size_len;
203         memcpy(&message[i], session_key->encrypted_key,
204                session_key->encrypted_key_size);
205         i += session_key->encrypted_key_size;
206         *packet_len = i;
207 out:
208         return rc;
209 }
210
211 static int
212 parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
213                     struct ecryptfs_message *msg)
214 {
215         size_t i = 0;
216         char *data;
217         size_t data_len;
218         size_t m_size;
219         size_t message_len;
220         u16 checksum = 0;
221         u16 expected_checksum = 0;
222         int rc;
223
224         /*
225          *              ***** TAG 65 Packet Format *****
226          *         | Content Type             | 1 byte       |
227          *         | Status Indicator         | 1 byte       |
228          *         | File Encryption Key Size | 1 or 2 bytes |
229          *         | File Encryption Key      | arbitrary    |
230          */
231         message_len = msg->data_len;
232         data = msg->data;
233         if (message_len < 4) {
234                 rc = -EIO;
235                 goto out;
236         }
237         if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
238                 ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
239                 rc = -EIO;
240                 goto out;
241         }
242         if (data[i++]) {
243                 ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
244                                 "[%d]\n", data[i-1]);
245                 rc = -EIO;
246                 goto out;
247         }
248         rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
249         if (rc) {
250                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
251                                 "rc = [%d]\n", rc);
252                 goto out;
253         }
254         i += data_len;
255         if (message_len < (i + m_size)) {
256                 ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
257                                 "is shorter than expected\n");
258                 rc = -EIO;
259                 goto out;
260         }
261         if (m_size < 3) {
262                 ecryptfs_printk(KERN_ERR,
263                                 "The decrypted key is not long enough to "
264                                 "include a cipher code and checksum\n");
265                 rc = -EIO;
266                 goto out;
267         }
268         *cipher_code = data[i++];
269         /* The decrypted key includes 1 byte cipher code and 2 byte checksum */
270         session_key->decrypted_key_size = m_size - 3;
271         if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
272                 ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
273                                 "the maximum key size [%d]\n",
274                                 session_key->decrypted_key_size,
275                                 ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
276                 rc = -EIO;
277                 goto out;
278         }
279         memcpy(session_key->decrypted_key, &data[i],
280                session_key->decrypted_key_size);
281         i += session_key->decrypted_key_size;
282         expected_checksum += (unsigned char)(data[i++]) << 8;
283         expected_checksum += (unsigned char)(data[i++]);
284         for (i = 0; i < session_key->decrypted_key_size; i++)
285                 checksum += session_key->decrypted_key[i];
286         if (expected_checksum != checksum) {
287                 ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
288                                 "encryption  key; expected [%x]; calculated "
289                                 "[%x]\n", expected_checksum, checksum);
290                 rc = -EIO;
291         }
292 out:
293         return rc;
294 }
295
296
297 static int
298 write_tag_66_packet(char *signature, u8 cipher_code,
299                     struct ecryptfs_crypt_stat *crypt_stat, char **packet,
300                     size_t *packet_len)
301 {
302         size_t i = 0;
303         size_t j;
304         size_t data_len;
305         size_t checksum = 0;
306         size_t packet_size_len;
307         char *message;
308         int rc;
309
310         /*
311          *              ***** TAG 66 Packet Format *****
312          *         | Content Type             | 1 byte       |
313          *         | Key Identifier Size      | 1 or 2 bytes |
314          *         | Key Identifier           | arbitrary    |
315          *         | File Encryption Key Size | 1 or 2 bytes |
316          *         | File Encryption Key      | arbitrary    |
317          */
318         data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
319         *packet = kmalloc(data_len, GFP_KERNEL);
320         message = *packet;
321         if (!message) {
322                 ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
323                 rc = -ENOMEM;
324                 goto out;
325         }
326         message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
327         rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
328                                           &packet_size_len);
329         if (rc) {
330                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
331                                 "header; cannot generate packet length\n");
332                 goto out;
333         }
334         i += packet_size_len;
335         memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
336         i += ECRYPTFS_SIG_SIZE_HEX;
337         /* The encrypted key includes 1 byte cipher code and 2 byte checksum */
338         rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
339                                           &packet_size_len);
340         if (rc) {
341                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
342                                 "header; cannot generate packet length\n");
343                 goto out;
344         }
345         i += packet_size_len;
346         message[i++] = cipher_code;
347         memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
348         i += crypt_stat->key_size;
349         for (j = 0; j < crypt_stat->key_size; j++)
350                 checksum += crypt_stat->key[j];
351         message[i++] = (checksum / 256) % 256;
352         message[i++] = (checksum % 256);
353         *packet_len = i;
354 out:
355         return rc;
356 }
357
358 static int
359 parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
360                     struct ecryptfs_message *msg)
361 {
362         size_t i = 0;
363         char *data;
364         size_t data_len;
365         size_t message_len;
366         int rc;
367
368         /*
369          *              ***** TAG 65 Packet Format *****
370          *    | Content Type                       | 1 byte       |
371          *    | Status Indicator                   | 1 byte       |
372          *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
373          *    | Encrypted File Encryption Key      | arbitrary    |
374          */
375         message_len = msg->data_len;
376         data = msg->data;
377         /* verify that everything through the encrypted FEK size is present */
378         if (message_len < 4) {
379                 rc = -EIO;
380                 printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
381                        "message length is [%d]\n", __func__, message_len, 4);
382                 goto out;
383         }
384         if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
385                 rc = -EIO;
386                 printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
387                        __func__);
388                 goto out;
389         }
390         if (data[i++]) {
391                 rc = -EIO;
392                 printk(KERN_ERR "%s: Status indicator has non zero "
393                        "value [%d]\n", __func__, data[i-1]);
394
395                 goto out;
396         }
397         rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
398                                           &data_len);
399         if (rc) {
400                 ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
401                                 "rc = [%d]\n", rc);
402                 goto out;
403         }
404         i += data_len;
405         if (message_len < (i + key_rec->enc_key_size)) {
406                 rc = -EIO;
407                 printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
408                        __func__, message_len, (i + key_rec->enc_key_size));
409                 goto out;
410         }
411         if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
412                 rc = -EIO;
413                 printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
414                        "the maximum key size [%d]\n", __func__,
415                        key_rec->enc_key_size,
416                        ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
417                 goto out;
418         }
419         memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
420 out:
421         return rc;
422 }
423
424 /**
425  * ecryptfs_verify_version
426  * @version: The version number to confirm
427  *
428  * Returns zero on good version; non-zero otherwise
429  */
430 static int ecryptfs_verify_version(u16 version)
431 {
432         int rc = 0;
433         unsigned char major;
434         unsigned char minor;
435
436         major = ((version >> 8) & 0xFF);
437         minor = (version & 0xFF);
438         if (major != ECRYPTFS_VERSION_MAJOR) {
439                 ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
440                                 "Expected [%d]; got [%d]\n",
441                                 ECRYPTFS_VERSION_MAJOR, major);
442                 rc = -EINVAL;
443                 goto out;
444         }
445         if (minor != ECRYPTFS_VERSION_MINOR) {
446                 ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
447                                 "Expected [%d]; got [%d]\n",
448                                 ECRYPTFS_VERSION_MINOR, minor);
449                 rc = -EINVAL;
450                 goto out;
451         }
452 out:
453         return rc;
454 }
455
456 /**
457  * ecryptfs_verify_auth_tok_from_key
458  * @auth_tok_key: key containing the authentication token
459  * @auth_tok: authentication token
460  *
461  * Returns zero on valid auth tok; -EINVAL otherwise
462  */
463 static int
464 ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
465                                   struct ecryptfs_auth_tok **auth_tok)
466 {
467         int rc = 0;
468
469         (*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
470         if (ecryptfs_verify_version((*auth_tok)->version)) {
471                 printk(KERN_ERR "Data structure version mismatch. Userspace "
472                        "tools must match eCryptfs kernel module with major "
473                        "version [%d] and minor version [%d]\n",
474                        ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
475                 rc = -EINVAL;
476                 goto out;
477         }
478         if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
479             && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
480                 printk(KERN_ERR "Invalid auth_tok structure "
481                        "returned from key query\n");
482                 rc = -EINVAL;
483                 goto out;
484         }
485 out:
486         return rc;
487 }
488
489 static int
490 ecryptfs_find_global_auth_tok_for_sig(
491         struct key **auth_tok_key,
492         struct ecryptfs_auth_tok **auth_tok,
493         struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
494 {
495         struct ecryptfs_global_auth_tok *walker;
496         int rc = 0;
497
498         (*auth_tok_key) = NULL;
499         (*auth_tok) = NULL;
500         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
501         list_for_each_entry(walker,
502                             &mount_crypt_stat->global_auth_tok_list,
503                             mount_crypt_stat_list) {
504                 if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
505                         continue;
506
507                 if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
508                         rc = -EINVAL;
509                         goto out;
510                 }
511
512                 rc = key_validate(walker->global_auth_tok_key);
513                 if (rc) {
514                         if (rc == -EKEYEXPIRED)
515                                 goto out;
516                         goto out_invalid_auth_tok;
517                 }
518
519                 down_write(&(walker->global_auth_tok_key->sem));
520                 rc = ecryptfs_verify_auth_tok_from_key(
521                                 walker->global_auth_tok_key, auth_tok);
522                 if (rc)
523                         goto out_invalid_auth_tok_unlock;
524
525                 (*auth_tok_key) = walker->global_auth_tok_key;
526                 key_get(*auth_tok_key);
527                 goto out;
528         }
529         rc = -ENOENT;
530         goto out;
531 out_invalid_auth_tok_unlock:
532         up_write(&(walker->global_auth_tok_key->sem));
533 out_invalid_auth_tok:
534         printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
535         walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
536         key_put(walker->global_auth_tok_key);
537         walker->global_auth_tok_key = NULL;
538 out:
539         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
540         return rc;
541 }
542
543 /**
544  * ecryptfs_find_auth_tok_for_sig
545  * @auth_tok: Set to the matching auth_tok; NULL if not found
546  * @crypt_stat: inode crypt_stat crypto context
547  * @sig: Sig of auth_tok to find
548  *
549  * For now, this function simply looks at the registered auth_tok's
550  * linked off the mount_crypt_stat, so all the auth_toks that can be
551  * used must be registered at mount time. This function could
552  * potentially try a lot harder to find auth_tok's (e.g., by calling
553  * out to ecryptfsd to dynamically retrieve an auth_tok object) so
554  * that static registration of auth_tok's will no longer be necessary.
555  *
556  * Returns zero on no error; non-zero on error
557  */
558 static int
559 ecryptfs_find_auth_tok_for_sig(
560         struct key **auth_tok_key,
561         struct ecryptfs_auth_tok **auth_tok,
562         struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
563         char *sig)
564 {
565         int rc = 0;
566
567         rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
568                                                    mount_crypt_stat, sig);
569         if (rc == -ENOENT) {
570                 /* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
571                  * mount_crypt_stat structure, we prevent to use auth toks that
572                  * are not inserted through the ecryptfs_add_global_auth_tok
573                  * function.
574                  */
575                 if (mount_crypt_stat->flags
576                                 & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
577                         return -EINVAL;
578
579                 rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
580                                                        sig);
581         }
582         return rc;
583 }
584
585 /**
586  * write_tag_70_packet can gobble a lot of stack space. We stuff most
587  * of the function's parameters in a kmalloc'd struct to help reduce
588  * eCryptfs' overall stack usage.
589  */
590 struct ecryptfs_write_tag_70_packet_silly_stack {
591         u8 cipher_code;
592         size_t max_packet_size;
593         size_t packet_size_len;
594         size_t block_aligned_filename_size;
595         size_t block_size;
596         size_t i;
597         size_t j;
598         size_t num_rand_bytes;
599         struct mutex *tfm_mutex;
600         char *block_aligned_filename;
601         struct ecryptfs_auth_tok *auth_tok;
602         struct scatterlist src_sg;
603         struct scatterlist dst_sg;
604         struct blkcipher_desc desc;
605         char iv[ECRYPTFS_MAX_IV_BYTES];
606         char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
607         char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
608         struct hash_desc hash_desc;
609         struct scatterlist hash_sg;
610 };
611
612 /**
613  * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
614  * @filename: NULL-terminated filename string
615  *
616  * This is the simplest mechanism for achieving filename encryption in
617  * eCryptfs. It encrypts the given filename with the mount-wide
618  * filename encryption key (FNEK) and stores it in a packet to @dest,
619  * which the callee will encode and write directly into the dentry
620  * name.
621  */
622 int
623 ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
624                              size_t *packet_size,
625                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
626                              char *filename, size_t filename_size)
627 {
628         struct ecryptfs_write_tag_70_packet_silly_stack *s;
629         struct key *auth_tok_key = NULL;
630         int rc = 0;
631
632         s = kmalloc(sizeof(*s), GFP_KERNEL);
633         if (!s) {
634                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
635                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
636                 rc = -ENOMEM;
637                 goto out;
638         }
639         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
640         (*packet_size) = 0;
641         rc = ecryptfs_find_auth_tok_for_sig(
642                 &auth_tok_key,
643                 &s->auth_tok, mount_crypt_stat,
644                 mount_crypt_stat->global_default_fnek_sig);
645         if (rc) {
646                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
647                        "fnek sig [%s]; rc = [%d]\n", __func__,
648                        mount_crypt_stat->global_default_fnek_sig, rc);
649                 goto out;
650         }
651         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
652                 &s->desc.tfm,
653                 &s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
654         if (unlikely(rc)) {
655                 printk(KERN_ERR "Internal error whilst attempting to get "
656                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
657                        mount_crypt_stat->global_default_fn_cipher_name, rc);
658                 goto out;
659         }
660         mutex_lock(s->tfm_mutex);
661         s->block_size = crypto_blkcipher_blocksize(s->desc.tfm);
662         /* Plus one for the \0 separator between the random prefix
663          * and the plaintext filename */
664         s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
665         s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
666         if ((s->block_aligned_filename_size % s->block_size) != 0) {
667                 s->num_rand_bytes += (s->block_size
668                                       - (s->block_aligned_filename_size
669                                          % s->block_size));
670                 s->block_aligned_filename_size = (s->num_rand_bytes
671                                                   + filename_size);
672         }
673         /* Octet 0: Tag 70 identifier
674          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
675          *              and block-aligned encrypted filename size)
676          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
677          * Octet N2-N3: Cipher identifier (1 octet)
678          * Octets N3-N4: Block-aligned encrypted filename
679          *  - Consists of a minimum number of random characters, a \0
680          *    separator, and then the filename */
681         s->max_packet_size = (1                   /* Tag 70 identifier */
682                               + 3                 /* Max Tag 70 packet size */
683                               + ECRYPTFS_SIG_SIZE /* FNEK sig */
684                               + 1                 /* Cipher identifier */
685                               + s->block_aligned_filename_size);
686         if (dest == NULL) {
687                 (*packet_size) = s->max_packet_size;
688                 goto out_unlock;
689         }
690         if (s->max_packet_size > (*remaining_bytes)) {
691                 printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
692                        "[%zd] available\n", __func__, s->max_packet_size,
693                        (*remaining_bytes));
694                 rc = -EINVAL;
695                 goto out_unlock;
696         }
697         s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
698                                             GFP_KERNEL);
699         if (!s->block_aligned_filename) {
700                 printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
701                        "kzalloc [%zd] bytes\n", __func__,
702                        s->block_aligned_filename_size);
703                 rc = -ENOMEM;
704                 goto out_unlock;
705         }
706         s->i = 0;
707         dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
708         rc = ecryptfs_write_packet_length(&dest[s->i],
709                                           (ECRYPTFS_SIG_SIZE
710                                            + 1 /* Cipher code */
711                                            + s->block_aligned_filename_size),
712                                           &s->packet_size_len);
713         if (rc) {
714                 printk(KERN_ERR "%s: Error generating tag 70 packet "
715                        "header; cannot generate packet length; rc = [%d]\n",
716                        __func__, rc);
717                 goto out_free_unlock;
718         }
719         s->i += s->packet_size_len;
720         ecryptfs_from_hex(&dest[s->i],
721                           mount_crypt_stat->global_default_fnek_sig,
722                           ECRYPTFS_SIG_SIZE);
723         s->i += ECRYPTFS_SIG_SIZE;
724         s->cipher_code = ecryptfs_code_for_cipher_string(
725                 mount_crypt_stat->global_default_fn_cipher_name,
726                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
727         if (s->cipher_code == 0) {
728                 printk(KERN_WARNING "%s: Unable to generate code for "
729                        "cipher [%s] with key bytes [%zd]\n", __func__,
730                        mount_crypt_stat->global_default_fn_cipher_name,
731                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
732                 rc = -EINVAL;
733                 goto out_free_unlock;
734         }
735         dest[s->i++] = s->cipher_code;
736         /* TODO: Support other key modules than passphrase for
737          * filename encryption */
738         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
739                 rc = -EOPNOTSUPP;
740                 printk(KERN_INFO "%s: Filename encryption only supports "
741                        "password tokens\n", __func__);
742                 goto out_free_unlock;
743         }
744         sg_init_one(
745                 &s->hash_sg,
746                 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
747                 s->auth_tok->token.password.session_key_encryption_key_bytes);
748         s->hash_desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
749         s->hash_desc.tfm = crypto_alloc_hash(ECRYPTFS_TAG_70_DIGEST, 0,
750                                              CRYPTO_ALG_ASYNC);
751         if (IS_ERR(s->hash_desc.tfm)) {
752                         rc = PTR_ERR(s->hash_desc.tfm);
753                         printk(KERN_ERR "%s: Error attempting to "
754                                "allocate hash crypto context; rc = [%d]\n",
755                                __func__, rc);
756                         goto out_free_unlock;
757         }
758         rc = crypto_hash_init(&s->hash_desc);
759         if (rc) {
760                 printk(KERN_ERR
761                        "%s: Error initializing crypto hash; rc = [%d]\n",
762                        __func__, rc);
763                 goto out_release_free_unlock;
764         }
765         rc = crypto_hash_update(
766                 &s->hash_desc, &s->hash_sg,
767                 s->auth_tok->token.password.session_key_encryption_key_bytes);
768         if (rc) {
769                 printk(KERN_ERR
770                        "%s: Error updating crypto hash; rc = [%d]\n",
771                        __func__, rc);
772                 goto out_release_free_unlock;
773         }
774         rc = crypto_hash_final(&s->hash_desc, s->hash);
775         if (rc) {
776                 printk(KERN_ERR
777                        "%s: Error finalizing crypto hash; rc = [%d]\n",
778                        __func__, rc);
779                 goto out_release_free_unlock;
780         }
781         for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
782                 s->block_aligned_filename[s->j] =
783                         s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
784                 if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
785                     == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
786                         sg_init_one(&s->hash_sg, (u8 *)s->hash,
787                                     ECRYPTFS_TAG_70_DIGEST_SIZE);
788                         rc = crypto_hash_init(&s->hash_desc);
789                         if (rc) {
790                                 printk(KERN_ERR
791                                        "%s: Error initializing crypto hash; "
792                                        "rc = [%d]\n", __func__, rc);
793                                 goto out_release_free_unlock;
794                         }
795                         rc = crypto_hash_update(&s->hash_desc, &s->hash_sg,
796                                                 ECRYPTFS_TAG_70_DIGEST_SIZE);
797                         if (rc) {
798                                 printk(KERN_ERR
799                                        "%s: Error updating crypto hash; "
800                                        "rc = [%d]\n", __func__, rc);
801                                 goto out_release_free_unlock;
802                         }
803                         rc = crypto_hash_final(&s->hash_desc, s->tmp_hash);
804                         if (rc) {
805                                 printk(KERN_ERR
806                                        "%s: Error finalizing crypto hash; "
807                                        "rc = [%d]\n", __func__, rc);
808                                 goto out_release_free_unlock;
809                         }
810                         memcpy(s->hash, s->tmp_hash,
811                                ECRYPTFS_TAG_70_DIGEST_SIZE);
812                 }
813                 if (s->block_aligned_filename[s->j] == '\0')
814                         s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
815         }
816         memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
817                filename_size);
818         rc = virt_to_scatterlist(s->block_aligned_filename,
819                                  s->block_aligned_filename_size, &s->src_sg, 1);
820         if (rc != 1) {
821                 printk(KERN_ERR "%s: Internal error whilst attempting to "
822                        "convert filename memory to scatterlist; "
823                        "expected rc = 1; got rc = [%d]. "
824                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
825                        s->block_aligned_filename_size);
826                 goto out_release_free_unlock;
827         }
828         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
829                                  &s->dst_sg, 1);
830         if (rc != 1) {
831                 printk(KERN_ERR "%s: Internal error whilst attempting to "
832                        "convert encrypted filename memory to scatterlist; "
833                        "expected rc = 1; got rc = [%d]. "
834                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
835                        s->block_aligned_filename_size);
836                 goto out_release_free_unlock;
837         }
838         /* The characters in the first block effectively do the job
839          * of the IV here, so we just use 0's for the IV. Note the
840          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
841          * >= ECRYPTFS_MAX_IV_BYTES. */
842         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
843         s->desc.info = s->iv;
844         rc = crypto_blkcipher_setkey(
845                 s->desc.tfm,
846                 s->auth_tok->token.password.session_key_encryption_key,
847                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
848         if (rc < 0) {
849                 printk(KERN_ERR "%s: Error setting key for crypto context; "
850                        "rc = [%d]. s->auth_tok->token.password.session_key_"
851                        "encryption_key = [0x%p]; mount_crypt_stat->"
852                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
853                        rc,
854                        s->auth_tok->token.password.session_key_encryption_key,
855                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
856                 goto out_release_free_unlock;
857         }
858         rc = crypto_blkcipher_encrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
859                                          s->block_aligned_filename_size);
860         if (rc) {
861                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
862                        "rc = [%d]\n", __func__, rc);
863                 goto out_release_free_unlock;
864         }
865         s->i += s->block_aligned_filename_size;
866         (*packet_size) = s->i;
867         (*remaining_bytes) -= (*packet_size);
868 out_release_free_unlock:
869         crypto_free_hash(s->hash_desc.tfm);
870 out_free_unlock:
871         kzfree(s->block_aligned_filename);
872 out_unlock:
873         mutex_unlock(s->tfm_mutex);
874 out:
875         if (auth_tok_key) {
876                 up_write(&(auth_tok_key->sem));
877                 key_put(auth_tok_key);
878         }
879         kfree(s);
880         return rc;
881 }
882
883 struct ecryptfs_parse_tag_70_packet_silly_stack {
884         u8 cipher_code;
885         size_t max_packet_size;
886         size_t packet_size_len;
887         size_t parsed_tag_70_packet_size;
888         size_t block_aligned_filename_size;
889         size_t block_size;
890         size_t i;
891         struct mutex *tfm_mutex;
892         char *decrypted_filename;
893         struct ecryptfs_auth_tok *auth_tok;
894         struct scatterlist src_sg;
895         struct scatterlist dst_sg;
896         struct blkcipher_desc desc;
897         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
898         char iv[ECRYPTFS_MAX_IV_BYTES];
899         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
900 };
901
902 /**
903  * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
904  * @filename: This function kmalloc's the memory for the filename
905  * @filename_size: This function sets this to the amount of memory
906  *                 kmalloc'd for the filename
907  * @packet_size: This function sets this to the the number of octets
908  *               in the packet parsed
909  * @mount_crypt_stat: The mount-wide cryptographic context
910  * @data: The memory location containing the start of the tag 70
911  *        packet
912  * @max_packet_size: The maximum legal size of the packet to be parsed
913  *                   from @data
914  *
915  * Returns zero on success; non-zero otherwise
916  */
917 int
918 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
919                              size_t *packet_size,
920                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
921                              char *data, size_t max_packet_size)
922 {
923         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
924         struct key *auth_tok_key = NULL;
925         int rc = 0;
926
927         (*packet_size) = 0;
928         (*filename_size) = 0;
929         (*filename) = NULL;
930         s = kmalloc(sizeof(*s), GFP_KERNEL);
931         if (!s) {
932                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
933                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
934                 rc = -ENOMEM;
935                 goto out;
936         }
937         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
938         if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
939                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
940                        "at least [%d]\n", __func__, max_packet_size,
941                         (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
942                 rc = -EINVAL;
943                 goto out;
944         }
945         /* Octet 0: Tag 70 identifier
946          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
947          *              and block-aligned encrypted filename size)
948          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
949          * Octet N2-N3: Cipher identifier (1 octet)
950          * Octets N3-N4: Block-aligned encrypted filename
951          *  - Consists of a minimum number of random numbers, a \0
952          *    separator, and then the filename */
953         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
954                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
955                        "tag [0x%.2x]\n", __func__,
956                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
957                 rc = -EINVAL;
958                 goto out;
959         }
960         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
961                                           &s->parsed_tag_70_packet_size,
962                                           &s->packet_size_len);
963         if (rc) {
964                 printk(KERN_WARNING "%s: Error parsing packet length; "
965                        "rc = [%d]\n", __func__, rc);
966                 goto out;
967         }
968         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
969                                           - ECRYPTFS_SIG_SIZE - 1);
970         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
971             > max_packet_size) {
972                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
973                        "size is [%zd]\n", __func__, max_packet_size,
974                        (1 + s->packet_size_len + 1
975                         + s->block_aligned_filename_size));
976                 rc = -EINVAL;
977                 goto out;
978         }
979         (*packet_size) += s->packet_size_len;
980         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
981                         ECRYPTFS_SIG_SIZE);
982         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
983         (*packet_size) += ECRYPTFS_SIG_SIZE;
984         s->cipher_code = data[(*packet_size)++];
985         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
986         if (rc) {
987                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
988                        __func__, s->cipher_code);
989                 goto out;
990         }
991         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
992                                             &s->auth_tok, mount_crypt_stat,
993                                             s->fnek_sig_hex);
994         if (rc) {
995                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
996                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
997                        rc);
998                 goto out;
999         }
1000         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
1001                                                         &s->tfm_mutex,
1002                                                         s->cipher_string);
1003         if (unlikely(rc)) {
1004                 printk(KERN_ERR "Internal error whilst attempting to get "
1005                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1006                        s->cipher_string, rc);
1007                 goto out;
1008         }
1009         mutex_lock(s->tfm_mutex);
1010         rc = virt_to_scatterlist(&data[(*packet_size)],
1011                                  s->block_aligned_filename_size, &s->src_sg, 1);
1012         if (rc != 1) {
1013                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1014                        "convert encrypted filename memory to scatterlist; "
1015                        "expected rc = 1; got rc = [%d]. "
1016                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
1017                        s->block_aligned_filename_size);
1018                 goto out_unlock;
1019         }
1020         (*packet_size) += s->block_aligned_filename_size;
1021         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1022                                         GFP_KERNEL);
1023         if (!s->decrypted_filename) {
1024                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1025                        "kmalloc [%zd] bytes\n", __func__,
1026                        s->block_aligned_filename_size);
1027                 rc = -ENOMEM;
1028                 goto out_unlock;
1029         }
1030         rc = virt_to_scatterlist(s->decrypted_filename,
1031                                  s->block_aligned_filename_size, &s->dst_sg, 1);
1032         if (rc != 1) {
1033                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1034                        "convert decrypted filename memory to scatterlist; "
1035                        "expected rc = 1; got rc = [%d]. "
1036                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
1037                        s->block_aligned_filename_size);
1038                 goto out_free_unlock;
1039         }
1040         /* The characters in the first block effectively do the job of
1041          * the IV here, so we just use 0's for the IV. Note the
1042          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1043          * >= ECRYPTFS_MAX_IV_BYTES. */
1044         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1045         s->desc.info = s->iv;
1046         /* TODO: Support other key modules than passphrase for
1047          * filename encryption */
1048         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1049                 rc = -EOPNOTSUPP;
1050                 printk(KERN_INFO "%s: Filename encryption only supports "
1051                        "password tokens\n", __func__);
1052                 goto out_free_unlock;
1053         }
1054         rc = crypto_blkcipher_setkey(
1055                 s->desc.tfm,
1056                 s->auth_tok->token.password.session_key_encryption_key,
1057                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1058         if (rc < 0) {
1059                 printk(KERN_ERR "%s: Error setting key for crypto context; "
1060                        "rc = [%d]. s->auth_tok->token.password.session_key_"
1061                        "encryption_key = [0x%p]; mount_crypt_stat->"
1062                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1063                        rc,
1064                        s->auth_tok->token.password.session_key_encryption_key,
1065                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
1066                 goto out_free_unlock;
1067         }
1068         rc = crypto_blkcipher_decrypt_iv(&s->desc, &s->dst_sg, &s->src_sg,
1069                                          s->block_aligned_filename_size);
1070         if (rc) {
1071                 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1072                        "rc = [%d]\n", __func__, rc);
1073                 goto out_free_unlock;
1074         }
1075         s->i = 0;
1076         while (s->decrypted_filename[s->i] != '\0'
1077                && s->i < s->block_aligned_filename_size)
1078                 s->i++;
1079         if (s->i == s->block_aligned_filename_size) {
1080                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1081                        "find valid separator between random characters and "
1082                        "the filename\n", __func__);
1083                 rc = -EINVAL;
1084                 goto out_free_unlock;
1085         }
1086         s->i++;
1087         (*filename_size) = (s->block_aligned_filename_size - s->i);
1088         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1089                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1090                        "invalid\n", __func__, (*filename_size));
1091                 rc = -EINVAL;
1092                 goto out_free_unlock;
1093         }
1094         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1095         if (!(*filename)) {
1096                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1097                        "kmalloc [%zd] bytes\n", __func__,
1098                        ((*filename_size) + 1));
1099                 rc = -ENOMEM;
1100                 goto out_free_unlock;
1101         }
1102         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1103         (*filename)[(*filename_size)] = '\0';
1104 out_free_unlock:
1105         kfree(s->decrypted_filename);
1106 out_unlock:
1107         mutex_unlock(s->tfm_mutex);
1108 out:
1109         if (rc) {
1110                 (*packet_size) = 0;
1111                 (*filename_size) = 0;
1112                 (*filename) = NULL;
1113         }
1114         if (auth_tok_key) {
1115                 up_write(&(auth_tok_key->sem));
1116                 key_put(auth_tok_key);
1117         }
1118         kfree(s);
1119         return rc;
1120 }
1121
1122 static int
1123 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1124 {
1125         int rc = 0;
1126
1127         (*sig) = NULL;
1128         switch (auth_tok->token_type) {
1129         case ECRYPTFS_PASSWORD:
1130                 (*sig) = auth_tok->token.password.signature;
1131                 break;
1132         case ECRYPTFS_PRIVATE_KEY:
1133                 (*sig) = auth_tok->token.private_key.signature;
1134                 break;
1135         default:
1136                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1137                        auth_tok->token_type);
1138                 rc = -EINVAL;
1139         }
1140         return rc;
1141 }
1142
1143 /**
1144  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1145  * @auth_tok: The key authentication token used to decrypt the session key
1146  * @crypt_stat: The cryptographic context
1147  *
1148  * Returns zero on success; non-zero error otherwise.
1149  */
1150 static int
1151 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1152                                   struct ecryptfs_crypt_stat *crypt_stat)
1153 {
1154         u8 cipher_code = 0;
1155         struct ecryptfs_msg_ctx *msg_ctx;
1156         struct ecryptfs_message *msg = NULL;
1157         char *auth_tok_sig;
1158         char *payload;
1159         size_t payload_len;
1160         int rc;
1161
1162         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1163         if (rc) {
1164                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1165                        auth_tok->token_type);
1166                 goto out;
1167         }
1168         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1169                                  &payload, &payload_len);
1170         if (rc) {
1171                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1172                 goto out;
1173         }
1174         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1175         if (rc) {
1176                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1177                                 "ecryptfsd\n");
1178                 goto out;
1179         }
1180         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1181         if (rc) {
1182                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1183                                 "from the user space daemon\n");
1184                 rc = -EIO;
1185                 goto out;
1186         }
1187         rc = parse_tag_65_packet(&(auth_tok->session_key),
1188                                  &cipher_code, msg);
1189         if (rc) {
1190                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1191                        rc);
1192                 goto out;
1193         }
1194         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1195         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1196                auth_tok->session_key.decrypted_key_size);
1197         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1198         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1199         if (rc) {
1200                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1201                                 cipher_code)
1202                 goto out;
1203         }
1204         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1205         if (ecryptfs_verbosity > 0) {
1206                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1207                 ecryptfs_dump_hex(crypt_stat->key,
1208                                   crypt_stat->key_size);
1209         }
1210 out:
1211         if (msg)
1212                 kfree(msg);
1213         return rc;
1214 }
1215
1216 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1217 {
1218         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1219         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1220
1221         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1222                                  auth_tok_list_head, list) {
1223                 list_del(&auth_tok_list_item->list);
1224                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1225                                 auth_tok_list_item);
1226         }
1227 }
1228
1229 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1230
1231 /**
1232  * parse_tag_1_packet
1233  * @crypt_stat: The cryptographic context to modify based on packet contents
1234  * @data: The raw bytes of the packet.
1235  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1236  *                 a new authentication token will be placed at the
1237  *                 end of this list for this packet.
1238  * @new_auth_tok: Pointer to a pointer to memory that this function
1239  *                allocates; sets the memory address of the pointer to
1240  *                NULL on error. This object is added to the
1241  *                auth_tok_list.
1242  * @packet_size: This function writes the size of the parsed packet
1243  *               into this memory location; zero on error.
1244  * @max_packet_size: The maximum allowable packet size
1245  *
1246  * Returns zero on success; non-zero on error.
1247  */
1248 static int
1249 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1250                    unsigned char *data, struct list_head *auth_tok_list,
1251                    struct ecryptfs_auth_tok **new_auth_tok,
1252                    size_t *packet_size, size_t max_packet_size)
1253 {
1254         size_t body_size;
1255         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1256         size_t length_size;
1257         int rc = 0;
1258
1259         (*packet_size) = 0;
1260         (*new_auth_tok) = NULL;
1261         /**
1262          * This format is inspired by OpenPGP; see RFC 2440
1263          * packet tag 1
1264          *
1265          * Tag 1 identifier (1 byte)
1266          * Max Tag 1 packet size (max 3 bytes)
1267          * Version (1 byte)
1268          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1269          * Cipher identifier (1 byte)
1270          * Encrypted key size (arbitrary)
1271          *
1272          * 12 bytes minimum packet size
1273          */
1274         if (unlikely(max_packet_size < 12)) {
1275                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1276                 rc = -EINVAL;
1277                 goto out;
1278         }
1279         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1280                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1281                        ECRYPTFS_TAG_1_PACKET_TYPE);
1282                 rc = -EINVAL;
1283                 goto out;
1284         }
1285         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1286          * at end of function upon failure */
1287         auth_tok_list_item =
1288                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1289                                   GFP_KERNEL);
1290         if (!auth_tok_list_item) {
1291                 printk(KERN_ERR "Unable to allocate memory\n");
1292                 rc = -ENOMEM;
1293                 goto out;
1294         }
1295         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1296         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1297                                           &length_size);
1298         if (rc) {
1299                 printk(KERN_WARNING "Error parsing packet length; "
1300                        "rc = [%d]\n", rc);
1301                 goto out_free;
1302         }
1303         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1304                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1305                 rc = -EINVAL;
1306                 goto out_free;
1307         }
1308         (*packet_size) += length_size;
1309         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1310                 printk(KERN_WARNING "Packet size exceeds max\n");
1311                 rc = -EINVAL;
1312                 goto out_free;
1313         }
1314         if (unlikely(data[(*packet_size)++] != 0x03)) {
1315                 printk(KERN_WARNING "Unknown version number [%d]\n",
1316                        data[(*packet_size) - 1]);
1317                 rc = -EINVAL;
1318                 goto out_free;
1319         }
1320         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1321                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1322         *packet_size += ECRYPTFS_SIG_SIZE;
1323         /* This byte is skipped because the kernel does not need to
1324          * know which public key encryption algorithm was used */
1325         (*packet_size)++;
1326         (*new_auth_tok)->session_key.encrypted_key_size =
1327                 body_size - (ECRYPTFS_SIG_SIZE + 2);
1328         if ((*new_auth_tok)->session_key.encrypted_key_size
1329             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1330                 printk(KERN_WARNING "Tag 1 packet contains key larger "
1331                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1332                 rc = -EINVAL;
1333                 goto out;
1334         }
1335         memcpy((*new_auth_tok)->session_key.encrypted_key,
1336                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1337         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1338         (*new_auth_tok)->session_key.flags &=
1339                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1340         (*new_auth_tok)->session_key.flags |=
1341                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1342         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1343         (*new_auth_tok)->flags = 0;
1344         (*new_auth_tok)->session_key.flags &=
1345                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1346         (*new_auth_tok)->session_key.flags &=
1347                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1348         list_add(&auth_tok_list_item->list, auth_tok_list);
1349         goto out;
1350 out_free:
1351         (*new_auth_tok) = NULL;
1352         memset(auth_tok_list_item, 0,
1353                sizeof(struct ecryptfs_auth_tok_list_item));
1354         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1355                         auth_tok_list_item);
1356 out:
1357         if (rc)
1358                 (*packet_size) = 0;
1359         return rc;
1360 }
1361
1362 /**
1363  * parse_tag_3_packet
1364  * @crypt_stat: The cryptographic context to modify based on packet
1365  *              contents.
1366  * @data: The raw bytes of the packet.
1367  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1368  *                 a new authentication token will be placed at the end
1369  *                 of this list for this packet.
1370  * @new_auth_tok: Pointer to a pointer to memory that this function
1371  *                allocates; sets the memory address of the pointer to
1372  *                NULL on error. This object is added to the
1373  *                auth_tok_list.
1374  * @packet_size: This function writes the size of the parsed packet
1375  *               into this memory location; zero on error.
1376  * @max_packet_size: maximum number of bytes to parse
1377  *
1378  * Returns zero on success; non-zero on error.
1379  */
1380 static int
1381 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1382                    unsigned char *data, struct list_head *auth_tok_list,
1383                    struct ecryptfs_auth_tok **new_auth_tok,
1384                    size_t *packet_size, size_t max_packet_size)
1385 {
1386         size_t body_size;
1387         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1388         size_t length_size;
1389         int rc = 0;
1390
1391         (*packet_size) = 0;
1392         (*new_auth_tok) = NULL;
1393         /**
1394          *This format is inspired by OpenPGP; see RFC 2440
1395          * packet tag 3
1396          *
1397          * Tag 3 identifier (1 byte)
1398          * Max Tag 3 packet size (max 3 bytes)
1399          * Version (1 byte)
1400          * Cipher code (1 byte)
1401          * S2K specifier (1 byte)
1402          * Hash identifier (1 byte)
1403          * Salt (ECRYPTFS_SALT_SIZE)
1404          * Hash iterations (1 byte)
1405          * Encrypted key (arbitrary)
1406          *
1407          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1408          */
1409         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1410                 printk(KERN_ERR "Max packet size too large\n");
1411                 rc = -EINVAL;
1412                 goto out;
1413         }
1414         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1415                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1416                        ECRYPTFS_TAG_3_PACKET_TYPE);
1417                 rc = -EINVAL;
1418                 goto out;
1419         }
1420         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1421          * at end of function upon failure */
1422         auth_tok_list_item =
1423             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1424         if (!auth_tok_list_item) {
1425                 printk(KERN_ERR "Unable to allocate memory\n");
1426                 rc = -ENOMEM;
1427                 goto out;
1428         }
1429         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1430         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1431                                           &length_size);
1432         if (rc) {
1433                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1434                        rc);
1435                 goto out_free;
1436         }
1437         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1438                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1439                 rc = -EINVAL;
1440                 goto out_free;
1441         }
1442         (*packet_size) += length_size;
1443         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1444                 printk(KERN_ERR "Packet size exceeds max\n");
1445                 rc = -EINVAL;
1446                 goto out_free;
1447         }
1448         (*new_auth_tok)->session_key.encrypted_key_size =
1449                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1450         if ((*new_auth_tok)->session_key.encrypted_key_size
1451             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1452                 printk(KERN_WARNING "Tag 3 packet contains key larger "
1453                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1454                 rc = -EINVAL;
1455                 goto out_free;
1456         }
1457         if (unlikely(data[(*packet_size)++] != 0x04)) {
1458                 printk(KERN_WARNING "Unknown version number [%d]\n",
1459                        data[(*packet_size) - 1]);
1460                 rc = -EINVAL;
1461                 goto out_free;
1462         }
1463         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1464                                             (u16)data[(*packet_size)]);
1465         if (rc)
1466                 goto out_free;
1467         /* A little extra work to differentiate among the AES key
1468          * sizes; see RFC2440 */
1469         switch(data[(*packet_size)++]) {
1470         case RFC2440_CIPHER_AES_192:
1471                 crypt_stat->key_size = 24;
1472                 break;
1473         default:
1474                 crypt_stat->key_size =
1475                         (*new_auth_tok)->session_key.encrypted_key_size;
1476         }
1477         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1478         if (rc)
1479                 goto out_free;
1480         if (unlikely(data[(*packet_size)++] != 0x03)) {
1481                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1482                 rc = -ENOSYS;
1483                 goto out_free;
1484         }
1485         /* TODO: finish the hash mapping */
1486         switch (data[(*packet_size)++]) {
1487         case 0x01: /* See RFC2440 for these numbers and their mappings */
1488                 /* Choose MD5 */
1489                 memcpy((*new_auth_tok)->token.password.salt,
1490                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1491                 (*packet_size) += ECRYPTFS_SALT_SIZE;
1492                 /* This conversion was taken straight from RFC2440 */
1493                 (*new_auth_tok)->token.password.hash_iterations =
1494                         ((u32) 16 + (data[(*packet_size)] & 15))
1495                                 << ((data[(*packet_size)] >> 4) + 6);
1496                 (*packet_size)++;
1497                 /* Friendly reminder:
1498                  * (*new_auth_tok)->session_key.encrypted_key_size =
1499                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1500                 memcpy((*new_auth_tok)->session_key.encrypted_key,
1501                        &data[(*packet_size)],
1502                        (*new_auth_tok)->session_key.encrypted_key_size);
1503                 (*packet_size) +=
1504                         (*new_auth_tok)->session_key.encrypted_key_size;
1505                 (*new_auth_tok)->session_key.flags &=
1506                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1507                 (*new_auth_tok)->session_key.flags |=
1508                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1509                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1510                 break;
1511         default:
1512                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1513                                 "[%d]\n", data[(*packet_size) - 1]);
1514                 rc = -ENOSYS;
1515                 goto out_free;
1516         }
1517         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1518         /* TODO: Parametarize; we might actually want userspace to
1519          * decrypt the session key. */
1520         (*new_auth_tok)->session_key.flags &=
1521                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1522         (*new_auth_tok)->session_key.flags &=
1523                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1524         list_add(&auth_tok_list_item->list, auth_tok_list);
1525         goto out;
1526 out_free:
1527         (*new_auth_tok) = NULL;
1528         memset(auth_tok_list_item, 0,
1529                sizeof(struct ecryptfs_auth_tok_list_item));
1530         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1531                         auth_tok_list_item);
1532 out:
1533         if (rc)
1534                 (*packet_size) = 0;
1535         return rc;
1536 }
1537
1538 /**
1539  * parse_tag_11_packet
1540  * @data: The raw bytes of the packet
1541  * @contents: This function writes the data contents of the literal
1542  *            packet into this memory location
1543  * @max_contents_bytes: The maximum number of bytes that this function
1544  *                      is allowed to write into contents
1545  * @tag_11_contents_size: This function writes the size of the parsed
1546  *                        contents into this memory location; zero on
1547  *                        error
1548  * @packet_size: This function writes the size of the parsed packet
1549  *               into this memory location; zero on error
1550  * @max_packet_size: maximum number of bytes to parse
1551  *
1552  * Returns zero on success; non-zero on error.
1553  */
1554 static int
1555 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1556                     size_t max_contents_bytes, size_t *tag_11_contents_size,
1557                     size_t *packet_size, size_t max_packet_size)
1558 {
1559         size_t body_size;
1560         size_t length_size;
1561         int rc = 0;
1562
1563         (*packet_size) = 0;
1564         (*tag_11_contents_size) = 0;
1565         /* This format is inspired by OpenPGP; see RFC 2440
1566          * packet tag 11
1567          *
1568          * Tag 11 identifier (1 byte)
1569          * Max Tag 11 packet size (max 3 bytes)
1570          * Binary format specifier (1 byte)
1571          * Filename length (1 byte)
1572          * Filename ("_CONSOLE") (8 bytes)
1573          * Modification date (4 bytes)
1574          * Literal data (arbitrary)
1575          *
1576          * We need at least 16 bytes of data for the packet to even be
1577          * valid.
1578          */
1579         if (max_packet_size < 16) {
1580                 printk(KERN_ERR "Maximum packet size too small\n");
1581                 rc = -EINVAL;
1582                 goto out;
1583         }
1584         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1585                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1586                 rc = -EINVAL;
1587                 goto out;
1588         }
1589         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1590                                           &length_size);
1591         if (rc) {
1592                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1593                 goto out;
1594         }
1595         if (body_size < 14) {
1596                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1597                 rc = -EINVAL;
1598                 goto out;
1599         }
1600         (*packet_size) += length_size;
1601         (*tag_11_contents_size) = (body_size - 14);
1602         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1603                 printk(KERN_ERR "Packet size exceeds max\n");
1604                 rc = -EINVAL;
1605                 goto out;
1606         }
1607         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1608                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1609                        "expected size\n");
1610                 rc = -EINVAL;
1611                 goto out;
1612         }
1613         if (data[(*packet_size)++] != 0x62) {
1614                 printk(KERN_WARNING "Unrecognizable packet\n");
1615                 rc = -EINVAL;
1616                 goto out;
1617         }
1618         if (data[(*packet_size)++] != 0x08) {
1619                 printk(KERN_WARNING "Unrecognizable packet\n");
1620                 rc = -EINVAL;
1621                 goto out;
1622         }
1623         (*packet_size) += 12; /* Ignore filename and modification date */
1624         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1625         (*packet_size) += (*tag_11_contents_size);
1626 out:
1627         if (rc) {
1628                 (*packet_size) = 0;
1629                 (*tag_11_contents_size) = 0;
1630         }
1631         return rc;
1632 }
1633
1634 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1635                                       struct ecryptfs_auth_tok **auth_tok,
1636                                       char *sig)
1637 {
1638         int rc = 0;
1639
1640         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1641         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1642                 printk(KERN_ERR "Could not find key with description: [%s]\n",
1643                        sig);
1644                 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1645                 (*auth_tok_key) = NULL;
1646                 goto out;
1647         }
1648         down_write(&(*auth_tok_key)->sem);
1649         rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1650         if (rc) {
1651                 up_write(&(*auth_tok_key)->sem);
1652                 key_put(*auth_tok_key);
1653                 (*auth_tok_key) = NULL;
1654                 goto out;
1655         }
1656 out:
1657         return rc;
1658 }
1659
1660 /**
1661  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1662  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1663  * @crypt_stat: The cryptographic context
1664  *
1665  * Returns zero on success; non-zero error otherwise
1666  */
1667 static int
1668 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1669                                          struct ecryptfs_crypt_stat *crypt_stat)
1670 {
1671         struct scatterlist dst_sg[2];
1672         struct scatterlist src_sg[2];
1673         struct mutex *tfm_mutex;
1674         struct blkcipher_desc desc = {
1675                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1676         };
1677         int rc = 0;
1678
1679         if (unlikely(ecryptfs_verbosity > 0)) {
1680                 ecryptfs_printk(
1681                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1682                         auth_tok->token.password.session_key_encryption_key_bytes);
1683                 ecryptfs_dump_hex(
1684                         auth_tok->token.password.session_key_encryption_key,
1685                         auth_tok->token.password.session_key_encryption_key_bytes);
1686         }
1687         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1688                                                         crypt_stat->cipher);
1689         if (unlikely(rc)) {
1690                 printk(KERN_ERR "Internal error whilst attempting to get "
1691                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1692                        crypt_stat->cipher, rc);
1693                 goto out;
1694         }
1695         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1696                                  auth_tok->session_key.encrypted_key_size,
1697                                  src_sg, 2);
1698         if (rc < 1 || rc > 2) {
1699                 printk(KERN_ERR "Internal error whilst attempting to convert "
1700                         "auth_tok->session_key.encrypted_key to scatterlist; "
1701                         "expected rc = 1; got rc = [%d]. "
1702                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1703                         auth_tok->session_key.encrypted_key_size);
1704                 goto out;
1705         }
1706         auth_tok->session_key.decrypted_key_size =
1707                 auth_tok->session_key.encrypted_key_size;
1708         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1709                                  auth_tok->session_key.decrypted_key_size,
1710                                  dst_sg, 2);
1711         if (rc < 1 || rc > 2) {
1712                 printk(KERN_ERR "Internal error whilst attempting to convert "
1713                         "auth_tok->session_key.decrypted_key to scatterlist; "
1714                         "expected rc = 1; got rc = [%d]\n", rc);
1715                 goto out;
1716         }
1717         mutex_lock(tfm_mutex);
1718         rc = crypto_blkcipher_setkey(
1719                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1720                 crypt_stat->key_size);
1721         if (unlikely(rc < 0)) {
1722                 mutex_unlock(tfm_mutex);
1723                 printk(KERN_ERR "Error setting key for crypto context\n");
1724                 rc = -EINVAL;
1725                 goto out;
1726         }
1727         rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1728                                       auth_tok->session_key.encrypted_key_size);
1729         mutex_unlock(tfm_mutex);
1730         if (unlikely(rc)) {
1731                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1732                 goto out;
1733         }
1734         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1735         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1736                auth_tok->session_key.decrypted_key_size);
1737         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1738         if (unlikely(ecryptfs_verbosity > 0)) {
1739                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1740                                 crypt_stat->key_size);
1741                 ecryptfs_dump_hex(crypt_stat->key,
1742                                   crypt_stat->key_size);
1743         }
1744 out:
1745         return rc;
1746 }
1747
1748 /**
1749  * ecryptfs_parse_packet_set
1750  * @crypt_stat: The cryptographic context
1751  * @src: Virtual address of region of memory containing the packets
1752  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1753  *
1754  * Get crypt_stat to have the file's session key if the requisite key
1755  * is available to decrypt the session key.
1756  *
1757  * Returns Zero if a valid authentication token was retrieved and
1758  * processed; negative value for file not encrypted or for error
1759  * conditions.
1760  */
1761 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1762                               unsigned char *src,
1763                               struct dentry *ecryptfs_dentry)
1764 {
1765         size_t i = 0;
1766         size_t found_auth_tok;
1767         size_t next_packet_is_auth_tok_packet;
1768         struct list_head auth_tok_list;
1769         struct ecryptfs_auth_tok *matching_auth_tok;
1770         struct ecryptfs_auth_tok *candidate_auth_tok;
1771         char *candidate_auth_tok_sig;
1772         size_t packet_size;
1773         struct ecryptfs_auth_tok *new_auth_tok;
1774         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1775         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1776         size_t tag_11_contents_size;
1777         size_t tag_11_packet_size;
1778         struct key *auth_tok_key = NULL;
1779         int rc = 0;
1780
1781         INIT_LIST_HEAD(&auth_tok_list);
1782         /* Parse the header to find as many packets as we can; these will be
1783          * added the our &auth_tok_list */
1784         next_packet_is_auth_tok_packet = 1;
1785         while (next_packet_is_auth_tok_packet) {
1786                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1787
1788                 switch (src[i]) {
1789                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1790                         rc = parse_tag_3_packet(crypt_stat,
1791                                                 (unsigned char *)&src[i],
1792                                                 &auth_tok_list, &new_auth_tok,
1793                                                 &packet_size, max_packet_size);
1794                         if (rc) {
1795                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1796                                                 "tag 3 packet\n");
1797                                 rc = -EIO;
1798                                 goto out_wipe_list;
1799                         }
1800                         i += packet_size;
1801                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1802                                                  sig_tmp_space,
1803                                                  ECRYPTFS_SIG_SIZE,
1804                                                  &tag_11_contents_size,
1805                                                  &tag_11_packet_size,
1806                                                  max_packet_size);
1807                         if (rc) {
1808                                 ecryptfs_printk(KERN_ERR, "No valid "
1809                                                 "(ecryptfs-specific) literal "
1810                                                 "packet containing "
1811                                                 "authentication token "
1812                                                 "signature found after "
1813                                                 "tag 3 packet\n");
1814                                 rc = -EIO;
1815                                 goto out_wipe_list;
1816                         }
1817                         i += tag_11_packet_size;
1818                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1819                                 ecryptfs_printk(KERN_ERR, "Expected "
1820                                                 "signature of size [%d]; "
1821                                                 "read size [%zd]\n",
1822                                                 ECRYPTFS_SIG_SIZE,
1823                                                 tag_11_contents_size);
1824                                 rc = -EIO;
1825                                 goto out_wipe_list;
1826                         }
1827                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1828                                         sig_tmp_space, tag_11_contents_size);
1829                         new_auth_tok->token.password.signature[
1830                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1831                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1832                         break;
1833                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1834                         rc = parse_tag_1_packet(crypt_stat,
1835                                                 (unsigned char *)&src[i],
1836                                                 &auth_tok_list, &new_auth_tok,
1837                                                 &packet_size, max_packet_size);
1838                         if (rc) {
1839                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1840                                                 "tag 1 packet\n");
1841                                 rc = -EIO;
1842                                 goto out_wipe_list;
1843                         }
1844                         i += packet_size;
1845                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1846                         break;
1847                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1848                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1849                                         "(Tag 11 not allowed by itself)\n");
1850                         rc = -EIO;
1851                         goto out_wipe_list;
1852                         break;
1853                 default:
1854                         ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1855                                         "of the file header; hex value of "
1856                                         "character is [0x%.2x]\n", i, src[i]);
1857                         next_packet_is_auth_tok_packet = 0;
1858                 }
1859         }
1860         if (list_empty(&auth_tok_list)) {
1861                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1862                        "eCryptfs file; this is not supported in this version "
1863                        "of the eCryptfs kernel module\n");
1864                 rc = -EINVAL;
1865                 goto out;
1866         }
1867         /* auth_tok_list contains the set of authentication tokens
1868          * parsed from the metadata. We need to find a matching
1869          * authentication token that has the secret component(s)
1870          * necessary to decrypt the EFEK in the auth_tok parsed from
1871          * the metadata. There may be several potential matches, but
1872          * just one will be sufficient to decrypt to get the FEK. */
1873 find_next_matching_auth_tok:
1874         found_auth_tok = 0;
1875         if (auth_tok_key) {
1876                 up_write(&(auth_tok_key->sem));
1877                 key_put(auth_tok_key);
1878                 auth_tok_key = NULL;
1879         }
1880         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1881                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1882                 if (unlikely(ecryptfs_verbosity > 0)) {
1883                         ecryptfs_printk(KERN_DEBUG,
1884                                         "Considering cadidate auth tok:\n");
1885                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1886                 }
1887                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1888                                                candidate_auth_tok);
1889                 if (rc) {
1890                         printk(KERN_ERR
1891                                "Unrecognized candidate auth tok type: [%d]\n",
1892                                candidate_auth_tok->token_type);
1893                         rc = -EINVAL;
1894                         goto out_wipe_list;
1895                 }
1896                 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1897                                                &matching_auth_tok,
1898                                                crypt_stat->mount_crypt_stat,
1899                                                candidate_auth_tok_sig);
1900                 if (!rc) {
1901                         found_auth_tok = 1;
1902                         goto found_matching_auth_tok;
1903                 }
1904         }
1905         if (!found_auth_tok) {
1906                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1907                                 "authentication token\n");
1908                 rc = -EIO;
1909                 goto out_wipe_list;
1910         }
1911 found_matching_auth_tok:
1912         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1913                 memcpy(&(candidate_auth_tok->token.private_key),
1914                        &(matching_auth_tok->token.private_key),
1915                        sizeof(struct ecryptfs_private_key));
1916                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1917                                                        crypt_stat);
1918         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1919                 memcpy(&(candidate_auth_tok->token.password),
1920                        &(matching_auth_tok->token.password),
1921                        sizeof(struct ecryptfs_password));
1922                 rc = decrypt_passphrase_encrypted_session_key(
1923                         candidate_auth_tok, crypt_stat);
1924         }
1925         if (rc) {
1926                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1927
1928                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1929                                 "session key for authentication token with sig "
1930                                 "[%.*s]; rc = [%d]. Removing auth tok "
1931                                 "candidate from the list and searching for "
1932                                 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1933                                 candidate_auth_tok_sig, rc);
1934                 list_for_each_entry_safe(auth_tok_list_item,
1935                                          auth_tok_list_item_tmp,
1936                                          &auth_tok_list, list) {
1937                         if (candidate_auth_tok
1938                             == &auth_tok_list_item->auth_tok) {
1939                                 list_del(&auth_tok_list_item->list);
1940                                 kmem_cache_free(
1941                                         ecryptfs_auth_tok_list_item_cache,
1942                                         auth_tok_list_item);
1943                                 goto find_next_matching_auth_tok;
1944                         }
1945                 }
1946                 BUG();
1947         }
1948         rc = ecryptfs_compute_root_iv(crypt_stat);
1949         if (rc) {
1950                 ecryptfs_printk(KERN_ERR, "Error computing "
1951                                 "the root IV\n");
1952                 goto out_wipe_list;
1953         }
1954         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1955         if (rc) {
1956                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1957                                 "context for cipher [%s]; rc = [%d]\n",
1958                                 crypt_stat->cipher, rc);
1959         }
1960 out_wipe_list:
1961         wipe_auth_tok_list(&auth_tok_list);
1962 out:
1963         if (auth_tok_key) {
1964                 up_write(&(auth_tok_key->sem));
1965                 key_put(auth_tok_key);
1966         }
1967         return rc;
1968 }
1969
1970 static int
1971 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1972                         struct ecryptfs_crypt_stat *crypt_stat,
1973                         struct ecryptfs_key_record *key_rec)
1974 {
1975         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1976         char *payload = NULL;
1977         size_t payload_len;
1978         struct ecryptfs_message *msg;
1979         int rc;
1980
1981         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1982                                  ecryptfs_code_for_cipher_string(
1983                                          crypt_stat->cipher,
1984                                          crypt_stat->key_size),
1985                                  crypt_stat, &payload, &payload_len);
1986         if (rc) {
1987                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1988                 goto out;
1989         }
1990         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1991         if (rc) {
1992                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1993                                 "ecryptfsd\n");
1994                 goto out;
1995         }
1996         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1997         if (rc) {
1998                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1999                                 "from the user space daemon\n");
2000                 rc = -EIO;
2001                 goto out;
2002         }
2003         rc = parse_tag_67_packet(key_rec, msg);
2004         if (rc)
2005                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2006         kfree(msg);
2007 out:
2008         kfree(payload);
2009         return rc;
2010 }
2011 /**
2012  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2013  * @dest: Buffer into which to write the packet
2014  * @remaining_bytes: Maximum number of bytes that can be writtn
2015  * @auth_tok: The authentication token used for generating the tag 1 packet
2016  * @crypt_stat: The cryptographic context
2017  * @key_rec: The key record struct for the tag 1 packet
2018  * @packet_size: This function will write the number of bytes that end
2019  *               up constituting the packet; set to zero on error
2020  *
2021  * Returns zero on success; non-zero on error.
2022  */
2023 static int
2024 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2025                    struct ecryptfs_auth_tok *auth_tok,
2026                    struct ecryptfs_crypt_stat *crypt_stat,
2027                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2028 {
2029         size_t i;
2030         size_t encrypted_session_key_valid = 0;
2031         size_t packet_size_length;
2032         size_t max_packet_size;
2033         int rc = 0;
2034
2035         (*packet_size) = 0;
2036         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2037                           ECRYPTFS_SIG_SIZE);
2038         encrypted_session_key_valid = 0;
2039         for (i = 0; i < crypt_stat->key_size; i++)
2040                 encrypted_session_key_valid |=
2041                         auth_tok->session_key.encrypted_key[i];
2042         if (encrypted_session_key_valid) {
2043                 memcpy(key_rec->enc_key,
2044                        auth_tok->session_key.encrypted_key,
2045                        auth_tok->session_key.encrypted_key_size);
2046                 goto encrypted_session_key_set;
2047         }
2048         if (auth_tok->session_key.encrypted_key_size == 0)
2049                 auth_tok->session_key.encrypted_key_size =
2050                         auth_tok->token.private_key.key_size;
2051         rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
2052         if (rc) {
2053                 printk(KERN_ERR "Failed to encrypt session key via a key "
2054                        "module; rc = [%d]\n", rc);
2055                 goto out;
2056         }
2057         if (ecryptfs_verbosity > 0) {
2058                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2059                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2060         }
2061 encrypted_session_key_set:
2062         /* This format is inspired by OpenPGP; see RFC 2440
2063          * packet tag 1 */
2064         max_packet_size = (1                         /* Tag 1 identifier */
2065                            + 3                       /* Max Tag 1 packet size */
2066                            + 1                       /* Version */
2067                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
2068                            + 1                       /* Cipher identifier */
2069                            + key_rec->enc_key_size); /* Encrypted key size */
2070         if (max_packet_size > (*remaining_bytes)) {
2071                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2072                        "need up to [%td] bytes, but there are only [%td] "
2073                        "available\n", max_packet_size, (*remaining_bytes));
2074                 rc = -EINVAL;
2075                 goto out;
2076         }
2077         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2078         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2079                                           (max_packet_size - 4),
2080                                           &packet_size_length);
2081         if (rc) {
2082                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2083                                 "header; cannot generate packet length\n");
2084                 goto out;
2085         }
2086         (*packet_size) += packet_size_length;
2087         dest[(*packet_size)++] = 0x03; /* version 3 */
2088         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2089         (*packet_size) += ECRYPTFS_SIG_SIZE;
2090         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2091         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2092                key_rec->enc_key_size);
2093         (*packet_size) += key_rec->enc_key_size;
2094 out:
2095         if (rc)
2096                 (*packet_size) = 0;
2097         else
2098                 (*remaining_bytes) -= (*packet_size);
2099         return rc;
2100 }
2101
2102 /**
2103  * write_tag_11_packet
2104  * @dest: Target into which Tag 11 packet is to be written
2105  * @remaining_bytes: Maximum packet length
2106  * @contents: Byte array of contents to copy in
2107  * @contents_length: Number of bytes in contents
2108  * @packet_length: Length of the Tag 11 packet written; zero on error
2109  *
2110  * Returns zero on success; non-zero on error.
2111  */
2112 static int
2113 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2114                     size_t contents_length, size_t *packet_length)
2115 {
2116         size_t packet_size_length;
2117         size_t max_packet_size;
2118         int rc = 0;
2119
2120         (*packet_length) = 0;
2121         /* This format is inspired by OpenPGP; see RFC 2440
2122          * packet tag 11 */
2123         max_packet_size = (1                   /* Tag 11 identifier */
2124                            + 3                 /* Max Tag 11 packet size */
2125                            + 1                 /* Binary format specifier */
2126                            + 1                 /* Filename length */
2127                            + 8                 /* Filename ("_CONSOLE") */
2128                            + 4                 /* Modification date */
2129                            + contents_length); /* Literal data */
2130         if (max_packet_size > (*remaining_bytes)) {
2131                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2132                        "need up to [%td] bytes, but there are only [%td] "
2133                        "available\n", max_packet_size, (*remaining_bytes));
2134                 rc = -EINVAL;
2135                 goto out;
2136         }
2137         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2138         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2139                                           (max_packet_size - 4),
2140                                           &packet_size_length);
2141         if (rc) {
2142                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2143                        "generate packet length. rc = [%d]\n", rc);
2144                 goto out;
2145         }
2146         (*packet_length) += packet_size_length;
2147         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2148         dest[(*packet_length)++] = 8;
2149         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2150         (*packet_length) += 8;
2151         memset(&dest[(*packet_length)], 0x00, 4);
2152         (*packet_length) += 4;
2153         memcpy(&dest[(*packet_length)], contents, contents_length);
2154         (*packet_length) += contents_length;
2155  out:
2156         if (rc)
2157                 (*packet_length) = 0;
2158         else
2159                 (*remaining_bytes) -= (*packet_length);
2160         return rc;
2161 }
2162
2163 /**
2164  * write_tag_3_packet
2165  * @dest: Buffer into which to write the packet
2166  * @remaining_bytes: Maximum number of bytes that can be written
2167  * @auth_tok: Authentication token
2168  * @crypt_stat: The cryptographic context
2169  * @key_rec: encrypted key
2170  * @packet_size: This function will write the number of bytes that end
2171  *               up constituting the packet; set to zero on error
2172  *
2173  * Returns zero on success; non-zero on error.
2174  */
2175 static int
2176 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2177                    struct ecryptfs_auth_tok *auth_tok,
2178                    struct ecryptfs_crypt_stat *crypt_stat,
2179                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2180 {
2181         size_t i;
2182         size_t encrypted_session_key_valid = 0;
2183         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2184         struct scatterlist dst_sg[2];
2185         struct scatterlist src_sg[2];
2186         struct mutex *tfm_mutex = NULL;
2187         u8 cipher_code;
2188         size_t packet_size_length;
2189         size_t max_packet_size;
2190         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2191                 crypt_stat->mount_crypt_stat;
2192         struct blkcipher_desc desc = {
2193                 .tfm = NULL,
2194                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2195         };
2196         int rc = 0;
2197
2198         (*packet_size) = 0;
2199         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2200                           ECRYPTFS_SIG_SIZE);
2201         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2202                                                         crypt_stat->cipher);
2203         if (unlikely(rc)) {
2204                 printk(KERN_ERR "Internal error whilst attempting to get "
2205                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2206                        crypt_stat->cipher, rc);
2207                 goto out;
2208         }
2209         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2210                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2211
2212                 printk(KERN_WARNING "No key size specified at mount; "
2213                        "defaulting to [%d]\n", alg->max_keysize);
2214                 mount_crypt_stat->global_default_cipher_key_size =
2215                         alg->max_keysize;
2216         }
2217         if (crypt_stat->key_size == 0)
2218                 crypt_stat->key_size =
2219                         mount_crypt_stat->global_default_cipher_key_size;
2220         if (auth_tok->session_key.encrypted_key_size == 0)
2221                 auth_tok->session_key.encrypted_key_size =
2222                         crypt_stat->key_size;
2223         if (crypt_stat->key_size == 24
2224             && strcmp("aes", crypt_stat->cipher) == 0) {
2225                 memset((crypt_stat->key + 24), 0, 8);
2226                 auth_tok->session_key.encrypted_key_size = 32;
2227         } else
2228                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2229         key_rec->enc_key_size =
2230                 auth_tok->session_key.encrypted_key_size;
2231         encrypted_session_key_valid = 0;
2232         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2233                 encrypted_session_key_valid |=
2234                         auth_tok->session_key.encrypted_key[i];
2235         if (encrypted_session_key_valid) {
2236                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2237                                 "using auth_tok->session_key.encrypted_key, "
2238                                 "where key_rec->enc_key_size = [%zd]\n",
2239                                 key_rec->enc_key_size);
2240                 memcpy(key_rec->enc_key,
2241                        auth_tok->session_key.encrypted_key,
2242                        key_rec->enc_key_size);
2243                 goto encrypted_session_key_set;
2244         }
2245         if (auth_tok->token.password.flags &
2246             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2247                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2248                                 "session key encryption key of size [%d]\n",
2249                                 auth_tok->token.password.
2250                                 session_key_encryption_key_bytes);
2251                 memcpy(session_key_encryption_key,
2252                        auth_tok->token.password.session_key_encryption_key,
2253                        crypt_stat->key_size);
2254                 ecryptfs_printk(KERN_DEBUG,
2255                                 "Cached session key " "encryption key: \n");
2256                 if (ecryptfs_verbosity > 0)
2257                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2258         }
2259         if (unlikely(ecryptfs_verbosity > 0)) {
2260                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2261                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2262         }
2263         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2264                                  src_sg, 2);
2265         if (rc < 1 || rc > 2) {
2266                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2267                                 "for crypt_stat session key; expected rc = 1; "
2268                                 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2269                                 rc, key_rec->enc_key_size);
2270                 rc = -ENOMEM;
2271                 goto out;
2272         }
2273         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2274                                  dst_sg, 2);
2275         if (rc < 1 || rc > 2) {
2276                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2277                                 "for crypt_stat encrypted session key; "
2278                                 "expected rc = 1; got rc = [%d]. "
2279                                 "key_rec->enc_key_size = [%zd]\n", rc,
2280                                 key_rec->enc_key_size);
2281                 rc = -ENOMEM;
2282                 goto out;
2283         }
2284         mutex_lock(tfm_mutex);
2285         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2286                                      crypt_stat->key_size);
2287         if (rc < 0) {
2288                 mutex_unlock(tfm_mutex);
2289                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2290                                 "context; rc = [%d]\n", rc);
2291                 goto out;
2292         }
2293         rc = 0;
2294         ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2295                         crypt_stat->key_size);
2296         rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2297                                       (*key_rec).enc_key_size);
2298         mutex_unlock(tfm_mutex);
2299         if (rc) {
2300                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2301                 goto out;
2302         }
2303         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2304         if (ecryptfs_verbosity > 0) {
2305                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2306                                 key_rec->enc_key_size);
2307                 ecryptfs_dump_hex(key_rec->enc_key,
2308                                   key_rec->enc_key_size);
2309         }
2310 encrypted_session_key_set:
2311         /* This format is inspired by OpenPGP; see RFC 2440
2312          * packet tag 3 */
2313         max_packet_size = (1                         /* Tag 3 identifier */
2314                            + 3                       /* Max Tag 3 packet size */
2315                            + 1                       /* Version */
2316                            + 1                       /* Cipher code */
2317                            + 1                       /* S2K specifier */
2318                            + 1                       /* Hash identifier */
2319                            + ECRYPTFS_SALT_SIZE      /* Salt */
2320                            + 1                       /* Hash iterations */
2321                            + key_rec->enc_key_size); /* Encrypted key size */
2322         if (max_packet_size > (*remaining_bytes)) {
2323                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2324                        "there are only [%td] available\n", max_packet_size,
2325                        (*remaining_bytes));
2326                 rc = -EINVAL;
2327                 goto out;
2328         }
2329         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2330         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2331          * to get the number of octets in the actual Tag 3 packet */
2332         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2333                                           (max_packet_size - 4),
2334                                           &packet_size_length);
2335         if (rc) {
2336                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2337                        "generate packet length. rc = [%d]\n", rc);
2338                 goto out;
2339         }
2340         (*packet_size) += packet_size_length;
2341         dest[(*packet_size)++] = 0x04; /* version 4 */
2342         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2343          * specified with strings */
2344         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2345                                                       crypt_stat->key_size);
2346         if (cipher_code == 0) {
2347                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2348                                 "cipher [%s]\n", crypt_stat->cipher);
2349                 rc = -EINVAL;
2350                 goto out;
2351         }
2352         dest[(*packet_size)++] = cipher_code;
2353         dest[(*packet_size)++] = 0x03;  /* S2K */
2354         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2355         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2356                ECRYPTFS_SALT_SIZE);
2357         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2358         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2359         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2360                key_rec->enc_key_size);
2361         (*packet_size) += key_rec->enc_key_size;
2362 out:
2363         if (rc)
2364                 (*packet_size) = 0;
2365         else
2366                 (*remaining_bytes) -= (*packet_size);
2367         return rc;
2368 }
2369
2370 struct kmem_cache *ecryptfs_key_record_cache;
2371
2372 /**
2373  * ecryptfs_generate_key_packet_set
2374  * @dest_base: Virtual address from which to write the key record set
2375  * @crypt_stat: The cryptographic context from which the
2376  *              authentication tokens will be retrieved
2377  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2378  *                   for the global parameters
2379  * @len: The amount written
2380  * @max: The maximum amount of data allowed to be written
2381  *
2382  * Generates a key packet set and writes it to the virtual address
2383  * passed in.
2384  *
2385  * Returns zero on success; non-zero on error.
2386  */
2387 int
2388 ecryptfs_generate_key_packet_set(char *dest_base,
2389                                  struct ecryptfs_crypt_stat *crypt_stat,
2390                                  struct dentry *ecryptfs_dentry, size_t *len,
2391                                  size_t max)
2392 {
2393         struct ecryptfs_auth_tok *auth_tok;
2394         struct key *auth_tok_key = NULL;
2395         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2396                 &ecryptfs_superblock_to_private(
2397                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2398         size_t written;
2399         struct ecryptfs_key_record *key_rec;
2400         struct ecryptfs_key_sig *key_sig;
2401         int rc = 0;
2402
2403         (*len) = 0;
2404         mutex_lock(&crypt_stat->keysig_list_mutex);
2405         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2406         if (!key_rec) {
2407                 rc = -ENOMEM;
2408                 goto out;
2409         }
2410         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2411                             crypt_stat_list) {
2412                 memset(key_rec, 0, sizeof(*key_rec));
2413                 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2414                                                            &auth_tok,
2415                                                            mount_crypt_stat,
2416                                                            key_sig->keysig);
2417                 if (rc) {
2418                         printk(KERN_WARNING "Unable to retrieve auth tok with "
2419                                "sig = [%s]\n", key_sig->keysig);
2420                         rc = process_find_global_auth_tok_for_sig_err(rc);
2421                         goto out_free;
2422                 }
2423                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2424                         rc = write_tag_3_packet((dest_base + (*len)),
2425                                                 &max, auth_tok,
2426                                                 crypt_stat, key_rec,
2427                                                 &written);
2428                         if (rc) {
2429                                 ecryptfs_printk(KERN_WARNING, "Error "
2430                                                 "writing tag 3 packet\n");
2431                                 goto out_free;
2432                         }
2433                         (*len) += written;
2434                         /* Write auth tok signature packet */
2435                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2436                                                  key_rec->sig,
2437                                                  ECRYPTFS_SIG_SIZE, &written);
2438                         if (rc) {
2439                                 ecryptfs_printk(KERN_ERR, "Error writing "
2440                                                 "auth tok signature packet\n");
2441                                 goto out_free;
2442                         }
2443                         (*len) += written;
2444                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2445                         rc = write_tag_1_packet(dest_base + (*len),
2446                                                 &max, auth_tok,
2447                                                 crypt_stat, key_rec, &written);
2448                         if (rc) {
2449                                 ecryptfs_printk(KERN_WARNING, "Error "
2450                                                 "writing tag 1 packet\n");
2451                                 goto out_free;
2452                         }
2453                         (*len) += written;
2454                 } else {
2455                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2456                                         "authentication token type\n");
2457                         rc = -EINVAL;
2458                         goto out_free;
2459                 }
2460                 up_write(&(auth_tok_key->sem));
2461                 key_put(auth_tok_key);
2462                 auth_tok_key = NULL;
2463         }
2464         if (likely(max > 0)) {
2465                 dest_base[(*len)] = 0x00;
2466         } else {
2467                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2468                 rc = -EIO;
2469         }
2470 out_free:
2471         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2472 out:
2473         if (rc)
2474                 (*len) = 0;
2475         if (auth_tok_key) {
2476                 up_write(&(auth_tok_key->sem));
2477                 key_put(auth_tok_key);
2478         }
2479
2480         mutex_unlock(&crypt_stat->keysig_list_mutex);
2481         return rc;
2482 }
2483
2484 struct kmem_cache *ecryptfs_key_sig_cache;
2485
2486 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2487 {
2488         struct ecryptfs_key_sig *new_key_sig;
2489
2490         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2491         if (!new_key_sig) {
2492                 printk(KERN_ERR
2493                        "Error allocating from ecryptfs_key_sig_cache\n");
2494                 return -ENOMEM;
2495         }
2496         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2497         new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2498         /* Caller must hold keysig_list_mutex */
2499         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2500
2501         return 0;
2502 }
2503
2504 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2505
2506 int
2507 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2508                              char *sig, u32 global_auth_tok_flags)
2509 {
2510         struct ecryptfs_global_auth_tok *new_auth_tok;
2511         int rc = 0;
2512
2513         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2514                                         GFP_KERNEL);
2515         if (!new_auth_tok) {
2516                 rc = -ENOMEM;
2517                 printk(KERN_ERR "Error allocating from "
2518                        "ecryptfs_global_auth_tok_cache\n");
2519                 goto out;
2520         }
2521         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2522         new_auth_tok->flags = global_auth_tok_flags;
2523         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2524         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2525         list_add(&new_auth_tok->mount_crypt_stat_list,
2526                  &mount_crypt_stat->global_auth_tok_list);
2527         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2528 out:
2529         return rc;
2530 }
2531