27a7fefb83eb07f04d092416654b3b3f4142e55d
[linux-2.6.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[2];
603         struct scatterlist dst_sg[2];
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, 2);
820         if (rc < 1) {
821                 printk(KERN_ERR "%s: Internal error whilst attempting to "
822                        "convert filename memory to scatterlist; rc = [%d]. "
823                        "block_aligned_filename_size = [%zd]\n", __func__, rc,
824                        s->block_aligned_filename_size);
825                 goto out_release_free_unlock;
826         }
827         rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
828                                  s->dst_sg, 2);
829         if (rc < 1) {
830                 printk(KERN_ERR "%s: Internal error whilst attempting to "
831                        "convert encrypted filename memory to scatterlist; "
832                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
833                        __func__, rc, s->block_aligned_filename_size);
834                 goto out_release_free_unlock;
835         }
836         /* The characters in the first block effectively do the job
837          * of the IV here, so we just use 0's for the IV. Note the
838          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
839          * >= ECRYPTFS_MAX_IV_BYTES. */
840         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
841         s->desc.info = s->iv;
842         rc = crypto_blkcipher_setkey(
843                 s->desc.tfm,
844                 s->auth_tok->token.password.session_key_encryption_key,
845                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
846         if (rc < 0) {
847                 printk(KERN_ERR "%s: Error setting key for crypto context; "
848                        "rc = [%d]. s->auth_tok->token.password.session_key_"
849                        "encryption_key = [0x%p]; mount_crypt_stat->"
850                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
851                        rc,
852                        s->auth_tok->token.password.session_key_encryption_key,
853                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
854                 goto out_release_free_unlock;
855         }
856         rc = crypto_blkcipher_encrypt_iv(&s->desc, s->dst_sg, s->src_sg,
857                                          s->block_aligned_filename_size);
858         if (rc) {
859                 printk(KERN_ERR "%s: Error attempting to encrypt filename; "
860                        "rc = [%d]\n", __func__, rc);
861                 goto out_release_free_unlock;
862         }
863         s->i += s->block_aligned_filename_size;
864         (*packet_size) = s->i;
865         (*remaining_bytes) -= (*packet_size);
866 out_release_free_unlock:
867         crypto_free_hash(s->hash_desc.tfm);
868 out_free_unlock:
869         kzfree(s->block_aligned_filename);
870 out_unlock:
871         mutex_unlock(s->tfm_mutex);
872 out:
873         if (auth_tok_key) {
874                 up_write(&(auth_tok_key->sem));
875                 key_put(auth_tok_key);
876         }
877         kfree(s);
878         return rc;
879 }
880
881 struct ecryptfs_parse_tag_70_packet_silly_stack {
882         u8 cipher_code;
883         size_t max_packet_size;
884         size_t packet_size_len;
885         size_t parsed_tag_70_packet_size;
886         size_t block_aligned_filename_size;
887         size_t block_size;
888         size_t i;
889         struct mutex *tfm_mutex;
890         char *decrypted_filename;
891         struct ecryptfs_auth_tok *auth_tok;
892         struct scatterlist src_sg[2];
893         struct scatterlist dst_sg[2];
894         struct blkcipher_desc desc;
895         char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
896         char iv[ECRYPTFS_MAX_IV_BYTES];
897         char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE];
898 };
899
900 /**
901  * parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
902  * @filename: This function kmalloc's the memory for the filename
903  * @filename_size: This function sets this to the amount of memory
904  *                 kmalloc'd for the filename
905  * @packet_size: This function sets this to the the number of octets
906  *               in the packet parsed
907  * @mount_crypt_stat: The mount-wide cryptographic context
908  * @data: The memory location containing the start of the tag 70
909  *        packet
910  * @max_packet_size: The maximum legal size of the packet to be parsed
911  *                   from @data
912  *
913  * Returns zero on success; non-zero otherwise
914  */
915 int
916 ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
917                              size_t *packet_size,
918                              struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
919                              char *data, size_t max_packet_size)
920 {
921         struct ecryptfs_parse_tag_70_packet_silly_stack *s;
922         struct key *auth_tok_key = NULL;
923         int rc = 0;
924
925         (*packet_size) = 0;
926         (*filename_size) = 0;
927         (*filename) = NULL;
928         s = kmalloc(sizeof(*s), GFP_KERNEL);
929         if (!s) {
930                 printk(KERN_ERR "%s: Out of memory whilst trying to kmalloc "
931                        "[%zd] bytes of kernel memory\n", __func__, sizeof(*s));
932                 rc = -ENOMEM;
933                 goto out;
934         }
935         s->desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
936         if (max_packet_size < (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1)) {
937                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
938                        "at least [%d]\n", __func__, max_packet_size,
939                         (1 + 1 + ECRYPTFS_SIG_SIZE + 1 + 1));
940                 rc = -EINVAL;
941                 goto out;
942         }
943         /* Octet 0: Tag 70 identifier
944          * Octets 1-N1: Tag 70 packet size (includes cipher identifier
945          *              and block-aligned encrypted filename size)
946          * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
947          * Octet N2-N3: Cipher identifier (1 octet)
948          * Octets N3-N4: Block-aligned encrypted filename
949          *  - Consists of a minimum number of random numbers, a \0
950          *    separator, and then the filename */
951         if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
952                 printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
953                        "tag [0x%.2x]\n", __func__,
954                        data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
955                 rc = -EINVAL;
956                 goto out;
957         }
958         rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
959                                           &s->parsed_tag_70_packet_size,
960                                           &s->packet_size_len);
961         if (rc) {
962                 printk(KERN_WARNING "%s: Error parsing packet length; "
963                        "rc = [%d]\n", __func__, rc);
964                 goto out;
965         }
966         s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
967                                           - ECRYPTFS_SIG_SIZE - 1);
968         if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
969             > max_packet_size) {
970                 printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
971                        "size is [%zd]\n", __func__, max_packet_size,
972                        (1 + s->packet_size_len + 1
973                         + s->block_aligned_filename_size));
974                 rc = -EINVAL;
975                 goto out;
976         }
977         (*packet_size) += s->packet_size_len;
978         ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
979                         ECRYPTFS_SIG_SIZE);
980         s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
981         (*packet_size) += ECRYPTFS_SIG_SIZE;
982         s->cipher_code = data[(*packet_size)++];
983         rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
984         if (rc) {
985                 printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
986                        __func__, s->cipher_code);
987                 goto out;
988         }
989         rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
990                                             &s->auth_tok, mount_crypt_stat,
991                                             s->fnek_sig_hex);
992         if (rc) {
993                 printk(KERN_ERR "%s: Error attempting to find auth tok for "
994                        "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
995                        rc);
996                 goto out;
997         }
998         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->desc.tfm,
999                                                         &s->tfm_mutex,
1000                                                         s->cipher_string);
1001         if (unlikely(rc)) {
1002                 printk(KERN_ERR "Internal error whilst attempting to get "
1003                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1004                        s->cipher_string, rc);
1005                 goto out;
1006         }
1007         mutex_lock(s->tfm_mutex);
1008         rc = virt_to_scatterlist(&data[(*packet_size)],
1009                                  s->block_aligned_filename_size, s->src_sg, 2);
1010         if (rc < 1) {
1011                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1012                        "convert encrypted filename memory to scatterlist; "
1013                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1014                        __func__, rc, s->block_aligned_filename_size);
1015                 goto out_unlock;
1016         }
1017         (*packet_size) += s->block_aligned_filename_size;
1018         s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
1019                                         GFP_KERNEL);
1020         if (!s->decrypted_filename) {
1021                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1022                        "kmalloc [%zd] bytes\n", __func__,
1023                        s->block_aligned_filename_size);
1024                 rc = -ENOMEM;
1025                 goto out_unlock;
1026         }
1027         rc = virt_to_scatterlist(s->decrypted_filename,
1028                                  s->block_aligned_filename_size, s->dst_sg, 2);
1029         if (rc < 1) {
1030                 printk(KERN_ERR "%s: Internal error whilst attempting to "
1031                        "convert decrypted filename memory to scatterlist; "
1032                        "rc = [%d]. block_aligned_filename_size = [%zd]\n",
1033                        __func__, rc, s->block_aligned_filename_size);
1034                 goto out_free_unlock;
1035         }
1036         /* The characters in the first block effectively do the job of
1037          * the IV here, so we just use 0's for the IV. Note the
1038          * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
1039          * >= ECRYPTFS_MAX_IV_BYTES. */
1040         memset(s->iv, 0, ECRYPTFS_MAX_IV_BYTES);
1041         s->desc.info = s->iv;
1042         /* TODO: Support other key modules than passphrase for
1043          * filename encryption */
1044         if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
1045                 rc = -EOPNOTSUPP;
1046                 printk(KERN_INFO "%s: Filename encryption only supports "
1047                        "password tokens\n", __func__);
1048                 goto out_free_unlock;
1049         }
1050         rc = crypto_blkcipher_setkey(
1051                 s->desc.tfm,
1052                 s->auth_tok->token.password.session_key_encryption_key,
1053                 mount_crypt_stat->global_default_fn_cipher_key_bytes);
1054         if (rc < 0) {
1055                 printk(KERN_ERR "%s: Error setting key for crypto context; "
1056                        "rc = [%d]. s->auth_tok->token.password.session_key_"
1057                        "encryption_key = [0x%p]; mount_crypt_stat->"
1058                        "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
1059                        rc,
1060                        s->auth_tok->token.password.session_key_encryption_key,
1061                        mount_crypt_stat->global_default_fn_cipher_key_bytes);
1062                 goto out_free_unlock;
1063         }
1064         rc = crypto_blkcipher_decrypt_iv(&s->desc, s->dst_sg, s->src_sg,
1065                                          s->block_aligned_filename_size);
1066         if (rc) {
1067                 printk(KERN_ERR "%s: Error attempting to decrypt filename; "
1068                        "rc = [%d]\n", __func__, rc);
1069                 goto out_free_unlock;
1070         }
1071         s->i = 0;
1072         while (s->decrypted_filename[s->i] != '\0'
1073                && s->i < s->block_aligned_filename_size)
1074                 s->i++;
1075         if (s->i == s->block_aligned_filename_size) {
1076                 printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
1077                        "find valid separator between random characters and "
1078                        "the filename\n", __func__);
1079                 rc = -EINVAL;
1080                 goto out_free_unlock;
1081         }
1082         s->i++;
1083         (*filename_size) = (s->block_aligned_filename_size - s->i);
1084         if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
1085                 printk(KERN_WARNING "%s: Filename size is [%zd], which is "
1086                        "invalid\n", __func__, (*filename_size));
1087                 rc = -EINVAL;
1088                 goto out_free_unlock;
1089         }
1090         (*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
1091         if (!(*filename)) {
1092                 printk(KERN_ERR "%s: Out of memory whilst attempting to "
1093                        "kmalloc [%zd] bytes\n", __func__,
1094                        ((*filename_size) + 1));
1095                 rc = -ENOMEM;
1096                 goto out_free_unlock;
1097         }
1098         memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
1099         (*filename)[(*filename_size)] = '\0';
1100 out_free_unlock:
1101         kfree(s->decrypted_filename);
1102 out_unlock:
1103         mutex_unlock(s->tfm_mutex);
1104 out:
1105         if (rc) {
1106                 (*packet_size) = 0;
1107                 (*filename_size) = 0;
1108                 (*filename) = NULL;
1109         }
1110         if (auth_tok_key) {
1111                 up_write(&(auth_tok_key->sem));
1112                 key_put(auth_tok_key);
1113         }
1114         kfree(s);
1115         return rc;
1116 }
1117
1118 static int
1119 ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
1120 {
1121         int rc = 0;
1122
1123         (*sig) = NULL;
1124         switch (auth_tok->token_type) {
1125         case ECRYPTFS_PASSWORD:
1126                 (*sig) = auth_tok->token.password.signature;
1127                 break;
1128         case ECRYPTFS_PRIVATE_KEY:
1129                 (*sig) = auth_tok->token.private_key.signature;
1130                 break;
1131         default:
1132                 printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
1133                        auth_tok->token_type);
1134                 rc = -EINVAL;
1135         }
1136         return rc;
1137 }
1138
1139 /**
1140  * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
1141  * @auth_tok: The key authentication token used to decrypt the session key
1142  * @crypt_stat: The cryptographic context
1143  *
1144  * Returns zero on success; non-zero error otherwise.
1145  */
1146 static int
1147 decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1148                                   struct ecryptfs_crypt_stat *crypt_stat)
1149 {
1150         u8 cipher_code = 0;
1151         struct ecryptfs_msg_ctx *msg_ctx;
1152         struct ecryptfs_message *msg = NULL;
1153         char *auth_tok_sig;
1154         char *payload;
1155         size_t payload_len;
1156         int rc;
1157
1158         rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
1159         if (rc) {
1160                 printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
1161                        auth_tok->token_type);
1162                 goto out;
1163         }
1164         rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
1165                                  &payload, &payload_len);
1166         if (rc) {
1167                 ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
1168                 goto out;
1169         }
1170         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1171         if (rc) {
1172                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1173                                 "ecryptfsd\n");
1174                 goto out;
1175         }
1176         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1177         if (rc) {
1178                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
1179                                 "from the user space daemon\n");
1180                 rc = -EIO;
1181                 goto out;
1182         }
1183         rc = parse_tag_65_packet(&(auth_tok->session_key),
1184                                  &cipher_code, msg);
1185         if (rc) {
1186                 printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
1187                        rc);
1188                 goto out;
1189         }
1190         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1191         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1192                auth_tok->session_key.decrypted_key_size);
1193         crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
1194         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
1195         if (rc) {
1196                 ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
1197                                 cipher_code)
1198                 goto out;
1199         }
1200         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1201         if (ecryptfs_verbosity > 0) {
1202                 ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
1203                 ecryptfs_dump_hex(crypt_stat->key,
1204                                   crypt_stat->key_size);
1205         }
1206 out:
1207         if (msg)
1208                 kfree(msg);
1209         return rc;
1210 }
1211
1212 static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
1213 {
1214         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1215         struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1216
1217         list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
1218                                  auth_tok_list_head, list) {
1219                 list_del(&auth_tok_list_item->list);
1220                 kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1221                                 auth_tok_list_item);
1222         }
1223 }
1224
1225 struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
1226
1227 /**
1228  * parse_tag_1_packet
1229  * @crypt_stat: The cryptographic context to modify based on packet contents
1230  * @data: The raw bytes of the packet.
1231  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1232  *                 a new authentication token will be placed at the
1233  *                 end of this list for this packet.
1234  * @new_auth_tok: Pointer to a pointer to memory that this function
1235  *                allocates; sets the memory address of the pointer to
1236  *                NULL on error. This object is added to the
1237  *                auth_tok_list.
1238  * @packet_size: This function writes the size of the parsed packet
1239  *               into this memory location; zero on error.
1240  * @max_packet_size: The maximum allowable packet size
1241  *
1242  * Returns zero on success; non-zero on error.
1243  */
1244 static int
1245 parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
1246                    unsigned char *data, struct list_head *auth_tok_list,
1247                    struct ecryptfs_auth_tok **new_auth_tok,
1248                    size_t *packet_size, size_t max_packet_size)
1249 {
1250         size_t body_size;
1251         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1252         size_t length_size;
1253         int rc = 0;
1254
1255         (*packet_size) = 0;
1256         (*new_auth_tok) = NULL;
1257         /**
1258          * This format is inspired by OpenPGP; see RFC 2440
1259          * packet tag 1
1260          *
1261          * Tag 1 identifier (1 byte)
1262          * Max Tag 1 packet size (max 3 bytes)
1263          * Version (1 byte)
1264          * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
1265          * Cipher identifier (1 byte)
1266          * Encrypted key size (arbitrary)
1267          *
1268          * 12 bytes minimum packet size
1269          */
1270         if (unlikely(max_packet_size < 12)) {
1271                 printk(KERN_ERR "Invalid max packet size; must be >=12\n");
1272                 rc = -EINVAL;
1273                 goto out;
1274         }
1275         if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
1276                 printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
1277                        ECRYPTFS_TAG_1_PACKET_TYPE);
1278                 rc = -EINVAL;
1279                 goto out;
1280         }
1281         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1282          * at end of function upon failure */
1283         auth_tok_list_item =
1284                 kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
1285                                   GFP_KERNEL);
1286         if (!auth_tok_list_item) {
1287                 printk(KERN_ERR "Unable to allocate memory\n");
1288                 rc = -ENOMEM;
1289                 goto out;
1290         }
1291         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1292         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1293                                           &length_size);
1294         if (rc) {
1295                 printk(KERN_WARNING "Error parsing packet length; "
1296                        "rc = [%d]\n", rc);
1297                 goto out_free;
1298         }
1299         if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
1300                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1301                 rc = -EINVAL;
1302                 goto out_free;
1303         }
1304         (*packet_size) += length_size;
1305         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1306                 printk(KERN_WARNING "Packet size exceeds max\n");
1307                 rc = -EINVAL;
1308                 goto out_free;
1309         }
1310         if (unlikely(data[(*packet_size)++] != 0x03)) {
1311                 printk(KERN_WARNING "Unknown version number [%d]\n",
1312                        data[(*packet_size) - 1]);
1313                 rc = -EINVAL;
1314                 goto out_free;
1315         }
1316         ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
1317                         &data[(*packet_size)], ECRYPTFS_SIG_SIZE);
1318         *packet_size += ECRYPTFS_SIG_SIZE;
1319         /* This byte is skipped because the kernel does not need to
1320          * know which public key encryption algorithm was used */
1321         (*packet_size)++;
1322         (*new_auth_tok)->session_key.encrypted_key_size =
1323                 body_size - (ECRYPTFS_SIG_SIZE + 2);
1324         if ((*new_auth_tok)->session_key.encrypted_key_size
1325             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1326                 printk(KERN_WARNING "Tag 1 packet contains key larger "
1327                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES");
1328                 rc = -EINVAL;
1329                 goto out;
1330         }
1331         memcpy((*new_auth_tok)->session_key.encrypted_key,
1332                &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
1333         (*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
1334         (*new_auth_tok)->session_key.flags &=
1335                 ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1336         (*new_auth_tok)->session_key.flags |=
1337                 ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1338         (*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
1339         (*new_auth_tok)->flags = 0;
1340         (*new_auth_tok)->session_key.flags &=
1341                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1342         (*new_auth_tok)->session_key.flags &=
1343                 ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1344         list_add(&auth_tok_list_item->list, auth_tok_list);
1345         goto out;
1346 out_free:
1347         (*new_auth_tok) = NULL;
1348         memset(auth_tok_list_item, 0,
1349                sizeof(struct ecryptfs_auth_tok_list_item));
1350         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1351                         auth_tok_list_item);
1352 out:
1353         if (rc)
1354                 (*packet_size) = 0;
1355         return rc;
1356 }
1357
1358 /**
1359  * parse_tag_3_packet
1360  * @crypt_stat: The cryptographic context to modify based on packet
1361  *              contents.
1362  * @data: The raw bytes of the packet.
1363  * @auth_tok_list: eCryptfs parses packets into authentication tokens;
1364  *                 a new authentication token will be placed at the end
1365  *                 of this list for this packet.
1366  * @new_auth_tok: Pointer to a pointer to memory that this function
1367  *                allocates; sets the memory address of the pointer to
1368  *                NULL on error. This object is added to the
1369  *                auth_tok_list.
1370  * @packet_size: This function writes the size of the parsed packet
1371  *               into this memory location; zero on error.
1372  * @max_packet_size: maximum number of bytes to parse
1373  *
1374  * Returns zero on success; non-zero on error.
1375  */
1376 static int
1377 parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
1378                    unsigned char *data, struct list_head *auth_tok_list,
1379                    struct ecryptfs_auth_tok **new_auth_tok,
1380                    size_t *packet_size, size_t max_packet_size)
1381 {
1382         size_t body_size;
1383         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1384         size_t length_size;
1385         int rc = 0;
1386
1387         (*packet_size) = 0;
1388         (*new_auth_tok) = NULL;
1389         /**
1390          *This format is inspired by OpenPGP; see RFC 2440
1391          * packet tag 3
1392          *
1393          * Tag 3 identifier (1 byte)
1394          * Max Tag 3 packet size (max 3 bytes)
1395          * Version (1 byte)
1396          * Cipher code (1 byte)
1397          * S2K specifier (1 byte)
1398          * Hash identifier (1 byte)
1399          * Salt (ECRYPTFS_SALT_SIZE)
1400          * Hash iterations (1 byte)
1401          * Encrypted key (arbitrary)
1402          *
1403          * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
1404          */
1405         if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
1406                 printk(KERN_ERR "Max packet size too large\n");
1407                 rc = -EINVAL;
1408                 goto out;
1409         }
1410         if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
1411                 printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
1412                        ECRYPTFS_TAG_3_PACKET_TYPE);
1413                 rc = -EINVAL;
1414                 goto out;
1415         }
1416         /* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
1417          * at end of function upon failure */
1418         auth_tok_list_item =
1419             kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
1420         if (!auth_tok_list_item) {
1421                 printk(KERN_ERR "Unable to allocate memory\n");
1422                 rc = -ENOMEM;
1423                 goto out;
1424         }
1425         (*new_auth_tok) = &auth_tok_list_item->auth_tok;
1426         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1427                                           &length_size);
1428         if (rc) {
1429                 printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
1430                        rc);
1431                 goto out_free;
1432         }
1433         if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
1434                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1435                 rc = -EINVAL;
1436                 goto out_free;
1437         }
1438         (*packet_size) += length_size;
1439         if (unlikely((*packet_size) + body_size > max_packet_size)) {
1440                 printk(KERN_ERR "Packet size exceeds max\n");
1441                 rc = -EINVAL;
1442                 goto out_free;
1443         }
1444         (*new_auth_tok)->session_key.encrypted_key_size =
1445                 (body_size - (ECRYPTFS_SALT_SIZE + 5));
1446         if ((*new_auth_tok)->session_key.encrypted_key_size
1447             > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
1448                 printk(KERN_WARNING "Tag 3 packet contains key larger "
1449                        "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
1450                 rc = -EINVAL;
1451                 goto out_free;
1452         }
1453         if (unlikely(data[(*packet_size)++] != 0x04)) {
1454                 printk(KERN_WARNING "Unknown version number [%d]\n",
1455                        data[(*packet_size) - 1]);
1456                 rc = -EINVAL;
1457                 goto out_free;
1458         }
1459         rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
1460                                             (u16)data[(*packet_size)]);
1461         if (rc)
1462                 goto out_free;
1463         /* A little extra work to differentiate among the AES key
1464          * sizes; see RFC2440 */
1465         switch(data[(*packet_size)++]) {
1466         case RFC2440_CIPHER_AES_192:
1467                 crypt_stat->key_size = 24;
1468                 break;
1469         default:
1470                 crypt_stat->key_size =
1471                         (*new_auth_tok)->session_key.encrypted_key_size;
1472         }
1473         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1474         if (rc)
1475                 goto out_free;
1476         if (unlikely(data[(*packet_size)++] != 0x03)) {
1477                 printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
1478                 rc = -ENOSYS;
1479                 goto out_free;
1480         }
1481         /* TODO: finish the hash mapping */
1482         switch (data[(*packet_size)++]) {
1483         case 0x01: /* See RFC2440 for these numbers and their mappings */
1484                 /* Choose MD5 */
1485                 memcpy((*new_auth_tok)->token.password.salt,
1486                        &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
1487                 (*packet_size) += ECRYPTFS_SALT_SIZE;
1488                 /* This conversion was taken straight from RFC2440 */
1489                 (*new_auth_tok)->token.password.hash_iterations =
1490                         ((u32) 16 + (data[(*packet_size)] & 15))
1491                                 << ((data[(*packet_size)] >> 4) + 6);
1492                 (*packet_size)++;
1493                 /* Friendly reminder:
1494                  * (*new_auth_tok)->session_key.encrypted_key_size =
1495                  *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
1496                 memcpy((*new_auth_tok)->session_key.encrypted_key,
1497                        &data[(*packet_size)],
1498                        (*new_auth_tok)->session_key.encrypted_key_size);
1499                 (*packet_size) +=
1500                         (*new_auth_tok)->session_key.encrypted_key_size;
1501                 (*new_auth_tok)->session_key.flags &=
1502                         ~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1503                 (*new_auth_tok)->session_key.flags |=
1504                         ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
1505                 (*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
1506                 break;
1507         default:
1508                 ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
1509                                 "[%d]\n", data[(*packet_size) - 1]);
1510                 rc = -ENOSYS;
1511                 goto out_free;
1512         }
1513         (*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
1514         /* TODO: Parametarize; we might actually want userspace to
1515          * decrypt the session key. */
1516         (*new_auth_tok)->session_key.flags &=
1517                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
1518         (*new_auth_tok)->session_key.flags &=
1519                             ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
1520         list_add(&auth_tok_list_item->list, auth_tok_list);
1521         goto out;
1522 out_free:
1523         (*new_auth_tok) = NULL;
1524         memset(auth_tok_list_item, 0,
1525                sizeof(struct ecryptfs_auth_tok_list_item));
1526         kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
1527                         auth_tok_list_item);
1528 out:
1529         if (rc)
1530                 (*packet_size) = 0;
1531         return rc;
1532 }
1533
1534 /**
1535  * parse_tag_11_packet
1536  * @data: The raw bytes of the packet
1537  * @contents: This function writes the data contents of the literal
1538  *            packet into this memory location
1539  * @max_contents_bytes: The maximum number of bytes that this function
1540  *                      is allowed to write into contents
1541  * @tag_11_contents_size: This function writes the size of the parsed
1542  *                        contents into this memory location; zero on
1543  *                        error
1544  * @packet_size: This function writes the size of the parsed packet
1545  *               into this memory location; zero on error
1546  * @max_packet_size: maximum number of bytes to parse
1547  *
1548  * Returns zero on success; non-zero on error.
1549  */
1550 static int
1551 parse_tag_11_packet(unsigned char *data, unsigned char *contents,
1552                     size_t max_contents_bytes, size_t *tag_11_contents_size,
1553                     size_t *packet_size, size_t max_packet_size)
1554 {
1555         size_t body_size;
1556         size_t length_size;
1557         int rc = 0;
1558
1559         (*packet_size) = 0;
1560         (*tag_11_contents_size) = 0;
1561         /* This format is inspired by OpenPGP; see RFC 2440
1562          * packet tag 11
1563          *
1564          * Tag 11 identifier (1 byte)
1565          * Max Tag 11 packet size (max 3 bytes)
1566          * Binary format specifier (1 byte)
1567          * Filename length (1 byte)
1568          * Filename ("_CONSOLE") (8 bytes)
1569          * Modification date (4 bytes)
1570          * Literal data (arbitrary)
1571          *
1572          * We need at least 16 bytes of data for the packet to even be
1573          * valid.
1574          */
1575         if (max_packet_size < 16) {
1576                 printk(KERN_ERR "Maximum packet size too small\n");
1577                 rc = -EINVAL;
1578                 goto out;
1579         }
1580         if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
1581                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1582                 rc = -EINVAL;
1583                 goto out;
1584         }
1585         rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
1586                                           &length_size);
1587         if (rc) {
1588                 printk(KERN_WARNING "Invalid tag 11 packet format\n");
1589                 goto out;
1590         }
1591         if (body_size < 14) {
1592                 printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
1593                 rc = -EINVAL;
1594                 goto out;
1595         }
1596         (*packet_size) += length_size;
1597         (*tag_11_contents_size) = (body_size - 14);
1598         if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
1599                 printk(KERN_ERR "Packet size exceeds max\n");
1600                 rc = -EINVAL;
1601                 goto out;
1602         }
1603         if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
1604                 printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
1605                        "expected size\n");
1606                 rc = -EINVAL;
1607                 goto out;
1608         }
1609         if (data[(*packet_size)++] != 0x62) {
1610                 printk(KERN_WARNING "Unrecognizable packet\n");
1611                 rc = -EINVAL;
1612                 goto out;
1613         }
1614         if (data[(*packet_size)++] != 0x08) {
1615                 printk(KERN_WARNING "Unrecognizable packet\n");
1616                 rc = -EINVAL;
1617                 goto out;
1618         }
1619         (*packet_size) += 12; /* Ignore filename and modification date */
1620         memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
1621         (*packet_size) += (*tag_11_contents_size);
1622 out:
1623         if (rc) {
1624                 (*packet_size) = 0;
1625                 (*tag_11_contents_size) = 0;
1626         }
1627         return rc;
1628 }
1629
1630 int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
1631                                       struct ecryptfs_auth_tok **auth_tok,
1632                                       char *sig)
1633 {
1634         int rc = 0;
1635
1636         (*auth_tok_key) = request_key(&key_type_user, sig, NULL);
1637         if (!(*auth_tok_key) || IS_ERR(*auth_tok_key)) {
1638                 printk(KERN_ERR "Could not find key with description: [%s]\n",
1639                        sig);
1640                 rc = process_request_key_err(PTR_ERR(*auth_tok_key));
1641                 (*auth_tok_key) = NULL;
1642                 goto out;
1643         }
1644         down_write(&(*auth_tok_key)->sem);
1645         rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
1646         if (rc) {
1647                 up_write(&(*auth_tok_key)->sem);
1648                 key_put(*auth_tok_key);
1649                 (*auth_tok_key) = NULL;
1650                 goto out;
1651         }
1652 out:
1653         return rc;
1654 }
1655
1656 /**
1657  * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
1658  * @auth_tok: The passphrase authentication token to use to encrypt the FEK
1659  * @crypt_stat: The cryptographic context
1660  *
1661  * Returns zero on success; non-zero error otherwise
1662  */
1663 static int
1664 decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
1665                                          struct ecryptfs_crypt_stat *crypt_stat)
1666 {
1667         struct scatterlist dst_sg[2];
1668         struct scatterlist src_sg[2];
1669         struct mutex *tfm_mutex;
1670         struct blkcipher_desc desc = {
1671                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
1672         };
1673         int rc = 0;
1674
1675         if (unlikely(ecryptfs_verbosity > 0)) {
1676                 ecryptfs_printk(
1677                         KERN_DEBUG, "Session key encryption key (size [%d]):\n",
1678                         auth_tok->token.password.session_key_encryption_key_bytes);
1679                 ecryptfs_dump_hex(
1680                         auth_tok->token.password.session_key_encryption_key,
1681                         auth_tok->token.password.session_key_encryption_key_bytes);
1682         }
1683         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
1684                                                         crypt_stat->cipher);
1685         if (unlikely(rc)) {
1686                 printk(KERN_ERR "Internal error whilst attempting to get "
1687                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
1688                        crypt_stat->cipher, rc);
1689                 goto out;
1690         }
1691         rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
1692                                  auth_tok->session_key.encrypted_key_size,
1693                                  src_sg, 2);
1694         if (rc < 1 || rc > 2) {
1695                 printk(KERN_ERR "Internal error whilst attempting to convert "
1696                         "auth_tok->session_key.encrypted_key to scatterlist; "
1697                         "expected rc = 1; got rc = [%d]. "
1698                        "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
1699                         auth_tok->session_key.encrypted_key_size);
1700                 goto out;
1701         }
1702         auth_tok->session_key.decrypted_key_size =
1703                 auth_tok->session_key.encrypted_key_size;
1704         rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
1705                                  auth_tok->session_key.decrypted_key_size,
1706                                  dst_sg, 2);
1707         if (rc < 1 || rc > 2) {
1708                 printk(KERN_ERR "Internal error whilst attempting to convert "
1709                         "auth_tok->session_key.decrypted_key to scatterlist; "
1710                         "expected rc = 1; got rc = [%d]\n", rc);
1711                 goto out;
1712         }
1713         mutex_lock(tfm_mutex);
1714         rc = crypto_blkcipher_setkey(
1715                 desc.tfm, auth_tok->token.password.session_key_encryption_key,
1716                 crypt_stat->key_size);
1717         if (unlikely(rc < 0)) {
1718                 mutex_unlock(tfm_mutex);
1719                 printk(KERN_ERR "Error setting key for crypto context\n");
1720                 rc = -EINVAL;
1721                 goto out;
1722         }
1723         rc = crypto_blkcipher_decrypt(&desc, dst_sg, src_sg,
1724                                       auth_tok->session_key.encrypted_key_size);
1725         mutex_unlock(tfm_mutex);
1726         if (unlikely(rc)) {
1727                 printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
1728                 goto out;
1729         }
1730         auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
1731         memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
1732                auth_tok->session_key.decrypted_key_size);
1733         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
1734         if (unlikely(ecryptfs_verbosity > 0)) {
1735                 ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
1736                                 crypt_stat->key_size);
1737                 ecryptfs_dump_hex(crypt_stat->key,
1738                                   crypt_stat->key_size);
1739         }
1740 out:
1741         return rc;
1742 }
1743
1744 /**
1745  * ecryptfs_parse_packet_set
1746  * @crypt_stat: The cryptographic context
1747  * @src: Virtual address of region of memory containing the packets
1748  * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
1749  *
1750  * Get crypt_stat to have the file's session key if the requisite key
1751  * is available to decrypt the session key.
1752  *
1753  * Returns Zero if a valid authentication token was retrieved and
1754  * processed; negative value for file not encrypted or for error
1755  * conditions.
1756  */
1757 int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
1758                               unsigned char *src,
1759                               struct dentry *ecryptfs_dentry)
1760 {
1761         size_t i = 0;
1762         size_t found_auth_tok;
1763         size_t next_packet_is_auth_tok_packet;
1764         struct list_head auth_tok_list;
1765         struct ecryptfs_auth_tok *matching_auth_tok;
1766         struct ecryptfs_auth_tok *candidate_auth_tok;
1767         char *candidate_auth_tok_sig;
1768         size_t packet_size;
1769         struct ecryptfs_auth_tok *new_auth_tok;
1770         unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
1771         struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
1772         size_t tag_11_contents_size;
1773         size_t tag_11_packet_size;
1774         struct key *auth_tok_key = NULL;
1775         int rc = 0;
1776
1777         INIT_LIST_HEAD(&auth_tok_list);
1778         /* Parse the header to find as many packets as we can; these will be
1779          * added the our &auth_tok_list */
1780         next_packet_is_auth_tok_packet = 1;
1781         while (next_packet_is_auth_tok_packet) {
1782                 size_t max_packet_size = ((PAGE_CACHE_SIZE - 8) - i);
1783
1784                 switch (src[i]) {
1785                 case ECRYPTFS_TAG_3_PACKET_TYPE:
1786                         rc = parse_tag_3_packet(crypt_stat,
1787                                                 (unsigned char *)&src[i],
1788                                                 &auth_tok_list, &new_auth_tok,
1789                                                 &packet_size, max_packet_size);
1790                         if (rc) {
1791                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1792                                                 "tag 3 packet\n");
1793                                 rc = -EIO;
1794                                 goto out_wipe_list;
1795                         }
1796                         i += packet_size;
1797                         rc = parse_tag_11_packet((unsigned char *)&src[i],
1798                                                  sig_tmp_space,
1799                                                  ECRYPTFS_SIG_SIZE,
1800                                                  &tag_11_contents_size,
1801                                                  &tag_11_packet_size,
1802                                                  max_packet_size);
1803                         if (rc) {
1804                                 ecryptfs_printk(KERN_ERR, "No valid "
1805                                                 "(ecryptfs-specific) literal "
1806                                                 "packet containing "
1807                                                 "authentication token "
1808                                                 "signature found after "
1809                                                 "tag 3 packet\n");
1810                                 rc = -EIO;
1811                                 goto out_wipe_list;
1812                         }
1813                         i += tag_11_packet_size;
1814                         if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
1815                                 ecryptfs_printk(KERN_ERR, "Expected "
1816                                                 "signature of size [%d]; "
1817                                                 "read size [%zd]\n",
1818                                                 ECRYPTFS_SIG_SIZE,
1819                                                 tag_11_contents_size);
1820                                 rc = -EIO;
1821                                 goto out_wipe_list;
1822                         }
1823                         ecryptfs_to_hex(new_auth_tok->token.password.signature,
1824                                         sig_tmp_space, tag_11_contents_size);
1825                         new_auth_tok->token.password.signature[
1826                                 ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
1827                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1828                         break;
1829                 case ECRYPTFS_TAG_1_PACKET_TYPE:
1830                         rc = parse_tag_1_packet(crypt_stat,
1831                                                 (unsigned char *)&src[i],
1832                                                 &auth_tok_list, &new_auth_tok,
1833                                                 &packet_size, max_packet_size);
1834                         if (rc) {
1835                                 ecryptfs_printk(KERN_ERR, "Error parsing "
1836                                                 "tag 1 packet\n");
1837                                 rc = -EIO;
1838                                 goto out_wipe_list;
1839                         }
1840                         i += packet_size;
1841                         crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
1842                         break;
1843                 case ECRYPTFS_TAG_11_PACKET_TYPE:
1844                         ecryptfs_printk(KERN_WARNING, "Invalid packet set "
1845                                         "(Tag 11 not allowed by itself)\n");
1846                         rc = -EIO;
1847                         goto out_wipe_list;
1848                         break;
1849                 default:
1850                         ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
1851                                         "of the file header; hex value of "
1852                                         "character is [0x%.2x]\n", i, src[i]);
1853                         next_packet_is_auth_tok_packet = 0;
1854                 }
1855         }
1856         if (list_empty(&auth_tok_list)) {
1857                 printk(KERN_ERR "The lower file appears to be a non-encrypted "
1858                        "eCryptfs file; this is not supported in this version "
1859                        "of the eCryptfs kernel module\n");
1860                 rc = -EINVAL;
1861                 goto out;
1862         }
1863         /* auth_tok_list contains the set of authentication tokens
1864          * parsed from the metadata. We need to find a matching
1865          * authentication token that has the secret component(s)
1866          * necessary to decrypt the EFEK in the auth_tok parsed from
1867          * the metadata. There may be several potential matches, but
1868          * just one will be sufficient to decrypt to get the FEK. */
1869 find_next_matching_auth_tok:
1870         found_auth_tok = 0;
1871         if (auth_tok_key) {
1872                 up_write(&(auth_tok_key->sem));
1873                 key_put(auth_tok_key);
1874                 auth_tok_key = NULL;
1875         }
1876         list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
1877                 candidate_auth_tok = &auth_tok_list_item->auth_tok;
1878                 if (unlikely(ecryptfs_verbosity > 0)) {
1879                         ecryptfs_printk(KERN_DEBUG,
1880                                         "Considering cadidate auth tok:\n");
1881                         ecryptfs_dump_auth_tok(candidate_auth_tok);
1882                 }
1883                 rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
1884                                                candidate_auth_tok);
1885                 if (rc) {
1886                         printk(KERN_ERR
1887                                "Unrecognized candidate auth tok type: [%d]\n",
1888                                candidate_auth_tok->token_type);
1889                         rc = -EINVAL;
1890                         goto out_wipe_list;
1891                 }
1892                 rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
1893                                                &matching_auth_tok,
1894                                                crypt_stat->mount_crypt_stat,
1895                                                candidate_auth_tok_sig);
1896                 if (!rc) {
1897                         found_auth_tok = 1;
1898                         goto found_matching_auth_tok;
1899                 }
1900         }
1901         if (!found_auth_tok) {
1902                 ecryptfs_printk(KERN_ERR, "Could not find a usable "
1903                                 "authentication token\n");
1904                 rc = -EIO;
1905                 goto out_wipe_list;
1906         }
1907 found_matching_auth_tok:
1908         if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
1909                 memcpy(&(candidate_auth_tok->token.private_key),
1910                        &(matching_auth_tok->token.private_key),
1911                        sizeof(struct ecryptfs_private_key));
1912                 rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
1913                                                        crypt_stat);
1914         } else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
1915                 memcpy(&(candidate_auth_tok->token.password),
1916                        &(matching_auth_tok->token.password),
1917                        sizeof(struct ecryptfs_password));
1918                 rc = decrypt_passphrase_encrypted_session_key(
1919                         candidate_auth_tok, crypt_stat);
1920         }
1921         if (rc) {
1922                 struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
1923
1924                 ecryptfs_printk(KERN_WARNING, "Error decrypting the "
1925                                 "session key for authentication token with sig "
1926                                 "[%.*s]; rc = [%d]. Removing auth tok "
1927                                 "candidate from the list and searching for "
1928                                 "the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
1929                                 candidate_auth_tok_sig, rc);
1930                 list_for_each_entry_safe(auth_tok_list_item,
1931                                          auth_tok_list_item_tmp,
1932                                          &auth_tok_list, list) {
1933                         if (candidate_auth_tok
1934                             == &auth_tok_list_item->auth_tok) {
1935                                 list_del(&auth_tok_list_item->list);
1936                                 kmem_cache_free(
1937                                         ecryptfs_auth_tok_list_item_cache,
1938                                         auth_tok_list_item);
1939                                 goto find_next_matching_auth_tok;
1940                         }
1941                 }
1942                 BUG();
1943         }
1944         rc = ecryptfs_compute_root_iv(crypt_stat);
1945         if (rc) {
1946                 ecryptfs_printk(KERN_ERR, "Error computing "
1947                                 "the root IV\n");
1948                 goto out_wipe_list;
1949         }
1950         rc = ecryptfs_init_crypt_ctx(crypt_stat);
1951         if (rc) {
1952                 ecryptfs_printk(KERN_ERR, "Error initializing crypto "
1953                                 "context for cipher [%s]; rc = [%d]\n",
1954                                 crypt_stat->cipher, rc);
1955         }
1956 out_wipe_list:
1957         wipe_auth_tok_list(&auth_tok_list);
1958 out:
1959         if (auth_tok_key) {
1960                 up_write(&(auth_tok_key->sem));
1961                 key_put(auth_tok_key);
1962         }
1963         return rc;
1964 }
1965
1966 static int
1967 pki_encrypt_session_key(struct ecryptfs_auth_tok *auth_tok,
1968                         struct ecryptfs_crypt_stat *crypt_stat,
1969                         struct ecryptfs_key_record *key_rec)
1970 {
1971         struct ecryptfs_msg_ctx *msg_ctx = NULL;
1972         char *payload = NULL;
1973         size_t payload_len;
1974         struct ecryptfs_message *msg;
1975         int rc;
1976
1977         rc = write_tag_66_packet(auth_tok->token.private_key.signature,
1978                                  ecryptfs_code_for_cipher_string(
1979                                          crypt_stat->cipher,
1980                                          crypt_stat->key_size),
1981                                  crypt_stat, &payload, &payload_len);
1982         if (rc) {
1983                 ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
1984                 goto out;
1985         }
1986         rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
1987         if (rc) {
1988                 ecryptfs_printk(KERN_ERR, "Error sending message to "
1989                                 "ecryptfsd\n");
1990                 goto out;
1991         }
1992         rc = ecryptfs_wait_for_response(msg_ctx, &msg);
1993         if (rc) {
1994                 ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
1995                                 "from the user space daemon\n");
1996                 rc = -EIO;
1997                 goto out;
1998         }
1999         rc = parse_tag_67_packet(key_rec, msg);
2000         if (rc)
2001                 ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
2002         kfree(msg);
2003 out:
2004         kfree(payload);
2005         return rc;
2006 }
2007 /**
2008  * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
2009  * @dest: Buffer into which to write the packet
2010  * @remaining_bytes: Maximum number of bytes that can be writtn
2011  * @auth_tok: The authentication token used for generating the tag 1 packet
2012  * @crypt_stat: The cryptographic context
2013  * @key_rec: The key record struct for the tag 1 packet
2014  * @packet_size: This function will write the number of bytes that end
2015  *               up constituting the packet; set to zero on error
2016  *
2017  * Returns zero on success; non-zero on error.
2018  */
2019 static int
2020 write_tag_1_packet(char *dest, size_t *remaining_bytes,
2021                    struct ecryptfs_auth_tok *auth_tok,
2022                    struct ecryptfs_crypt_stat *crypt_stat,
2023                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2024 {
2025         size_t i;
2026         size_t encrypted_session_key_valid = 0;
2027         size_t packet_size_length;
2028         size_t max_packet_size;
2029         int rc = 0;
2030
2031         (*packet_size) = 0;
2032         ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
2033                           ECRYPTFS_SIG_SIZE);
2034         encrypted_session_key_valid = 0;
2035         for (i = 0; i < crypt_stat->key_size; i++)
2036                 encrypted_session_key_valid |=
2037                         auth_tok->session_key.encrypted_key[i];
2038         if (encrypted_session_key_valid) {
2039                 memcpy(key_rec->enc_key,
2040                        auth_tok->session_key.encrypted_key,
2041                        auth_tok->session_key.encrypted_key_size);
2042                 goto encrypted_session_key_set;
2043         }
2044         if (auth_tok->session_key.encrypted_key_size == 0)
2045                 auth_tok->session_key.encrypted_key_size =
2046                         auth_tok->token.private_key.key_size;
2047         rc = pki_encrypt_session_key(auth_tok, crypt_stat, key_rec);
2048         if (rc) {
2049                 printk(KERN_ERR "Failed to encrypt session key via a key "
2050                        "module; rc = [%d]\n", rc);
2051                 goto out;
2052         }
2053         if (ecryptfs_verbosity > 0) {
2054                 ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
2055                 ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
2056         }
2057 encrypted_session_key_set:
2058         /* This format is inspired by OpenPGP; see RFC 2440
2059          * packet tag 1 */
2060         max_packet_size = (1                         /* Tag 1 identifier */
2061                            + 3                       /* Max Tag 1 packet size */
2062                            + 1                       /* Version */
2063                            + ECRYPTFS_SIG_SIZE       /* Key identifier */
2064                            + 1                       /* Cipher identifier */
2065                            + key_rec->enc_key_size); /* Encrypted key size */
2066         if (max_packet_size > (*remaining_bytes)) {
2067                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2068                        "need up to [%td] bytes, but there are only [%td] "
2069                        "available\n", max_packet_size, (*remaining_bytes));
2070                 rc = -EINVAL;
2071                 goto out;
2072         }
2073         dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
2074         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2075                                           (max_packet_size - 4),
2076                                           &packet_size_length);
2077         if (rc) {
2078                 ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
2079                                 "header; cannot generate packet length\n");
2080                 goto out;
2081         }
2082         (*packet_size) += packet_size_length;
2083         dest[(*packet_size)++] = 0x03; /* version 3 */
2084         memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
2085         (*packet_size) += ECRYPTFS_SIG_SIZE;
2086         dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
2087         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2088                key_rec->enc_key_size);
2089         (*packet_size) += key_rec->enc_key_size;
2090 out:
2091         if (rc)
2092                 (*packet_size) = 0;
2093         else
2094                 (*remaining_bytes) -= (*packet_size);
2095         return rc;
2096 }
2097
2098 /**
2099  * write_tag_11_packet
2100  * @dest: Target into which Tag 11 packet is to be written
2101  * @remaining_bytes: Maximum packet length
2102  * @contents: Byte array of contents to copy in
2103  * @contents_length: Number of bytes in contents
2104  * @packet_length: Length of the Tag 11 packet written; zero on error
2105  *
2106  * Returns zero on success; non-zero on error.
2107  */
2108 static int
2109 write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
2110                     size_t contents_length, size_t *packet_length)
2111 {
2112         size_t packet_size_length;
2113         size_t max_packet_size;
2114         int rc = 0;
2115
2116         (*packet_length) = 0;
2117         /* This format is inspired by OpenPGP; see RFC 2440
2118          * packet tag 11 */
2119         max_packet_size = (1                   /* Tag 11 identifier */
2120                            + 3                 /* Max Tag 11 packet size */
2121                            + 1                 /* Binary format specifier */
2122                            + 1                 /* Filename length */
2123                            + 8                 /* Filename ("_CONSOLE") */
2124                            + 4                 /* Modification date */
2125                            + contents_length); /* Literal data */
2126         if (max_packet_size > (*remaining_bytes)) {
2127                 printk(KERN_ERR "Packet length larger than maximum allowable; "
2128                        "need up to [%td] bytes, but there are only [%td] "
2129                        "available\n", max_packet_size, (*remaining_bytes));
2130                 rc = -EINVAL;
2131                 goto out;
2132         }
2133         dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
2134         rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
2135                                           (max_packet_size - 4),
2136                                           &packet_size_length);
2137         if (rc) {
2138                 printk(KERN_ERR "Error generating tag 11 packet header; cannot "
2139                        "generate packet length. rc = [%d]\n", rc);
2140                 goto out;
2141         }
2142         (*packet_length) += packet_size_length;
2143         dest[(*packet_length)++] = 0x62; /* binary data format specifier */
2144         dest[(*packet_length)++] = 8;
2145         memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
2146         (*packet_length) += 8;
2147         memset(&dest[(*packet_length)], 0x00, 4);
2148         (*packet_length) += 4;
2149         memcpy(&dest[(*packet_length)], contents, contents_length);
2150         (*packet_length) += contents_length;
2151  out:
2152         if (rc)
2153                 (*packet_length) = 0;
2154         else
2155                 (*remaining_bytes) -= (*packet_length);
2156         return rc;
2157 }
2158
2159 /**
2160  * write_tag_3_packet
2161  * @dest: Buffer into which to write the packet
2162  * @remaining_bytes: Maximum number of bytes that can be written
2163  * @auth_tok: Authentication token
2164  * @crypt_stat: The cryptographic context
2165  * @key_rec: encrypted key
2166  * @packet_size: This function will write the number of bytes that end
2167  *               up constituting the packet; set to zero on error
2168  *
2169  * Returns zero on success; non-zero on error.
2170  */
2171 static int
2172 write_tag_3_packet(char *dest, size_t *remaining_bytes,
2173                    struct ecryptfs_auth_tok *auth_tok,
2174                    struct ecryptfs_crypt_stat *crypt_stat,
2175                    struct ecryptfs_key_record *key_rec, size_t *packet_size)
2176 {
2177         size_t i;
2178         size_t encrypted_session_key_valid = 0;
2179         char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
2180         struct scatterlist dst_sg[2];
2181         struct scatterlist src_sg[2];
2182         struct mutex *tfm_mutex = NULL;
2183         u8 cipher_code;
2184         size_t packet_size_length;
2185         size_t max_packet_size;
2186         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2187                 crypt_stat->mount_crypt_stat;
2188         struct blkcipher_desc desc = {
2189                 .tfm = NULL,
2190                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
2191         };
2192         int rc = 0;
2193
2194         (*packet_size) = 0;
2195         ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
2196                           ECRYPTFS_SIG_SIZE);
2197         rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&desc.tfm, &tfm_mutex,
2198                                                         crypt_stat->cipher);
2199         if (unlikely(rc)) {
2200                 printk(KERN_ERR "Internal error whilst attempting to get "
2201                        "tfm and mutex for cipher name [%s]; rc = [%d]\n",
2202                        crypt_stat->cipher, rc);
2203                 goto out;
2204         }
2205         if (mount_crypt_stat->global_default_cipher_key_size == 0) {
2206                 struct blkcipher_alg *alg = crypto_blkcipher_alg(desc.tfm);
2207
2208                 printk(KERN_WARNING "No key size specified at mount; "
2209                        "defaulting to [%d]\n", alg->max_keysize);
2210                 mount_crypt_stat->global_default_cipher_key_size =
2211                         alg->max_keysize;
2212         }
2213         if (crypt_stat->key_size == 0)
2214                 crypt_stat->key_size =
2215                         mount_crypt_stat->global_default_cipher_key_size;
2216         if (auth_tok->session_key.encrypted_key_size == 0)
2217                 auth_tok->session_key.encrypted_key_size =
2218                         crypt_stat->key_size;
2219         if (crypt_stat->key_size == 24
2220             && strcmp("aes", crypt_stat->cipher) == 0) {
2221                 memset((crypt_stat->key + 24), 0, 8);
2222                 auth_tok->session_key.encrypted_key_size = 32;
2223         } else
2224                 auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
2225         key_rec->enc_key_size =
2226                 auth_tok->session_key.encrypted_key_size;
2227         encrypted_session_key_valid = 0;
2228         for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
2229                 encrypted_session_key_valid |=
2230                         auth_tok->session_key.encrypted_key[i];
2231         if (encrypted_session_key_valid) {
2232                 ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
2233                                 "using auth_tok->session_key.encrypted_key, "
2234                                 "where key_rec->enc_key_size = [%zd]\n",
2235                                 key_rec->enc_key_size);
2236                 memcpy(key_rec->enc_key,
2237                        auth_tok->session_key.encrypted_key,
2238                        key_rec->enc_key_size);
2239                 goto encrypted_session_key_set;
2240         }
2241         if (auth_tok->token.password.flags &
2242             ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
2243                 ecryptfs_printk(KERN_DEBUG, "Using previously generated "
2244                                 "session key encryption key of size [%d]\n",
2245                                 auth_tok->token.password.
2246                                 session_key_encryption_key_bytes);
2247                 memcpy(session_key_encryption_key,
2248                        auth_tok->token.password.session_key_encryption_key,
2249                        crypt_stat->key_size);
2250                 ecryptfs_printk(KERN_DEBUG,
2251                                 "Cached session key " "encryption key: \n");
2252                 if (ecryptfs_verbosity > 0)
2253                         ecryptfs_dump_hex(session_key_encryption_key, 16);
2254         }
2255         if (unlikely(ecryptfs_verbosity > 0)) {
2256                 ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
2257                 ecryptfs_dump_hex(session_key_encryption_key, 16);
2258         }
2259         rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
2260                                  src_sg, 2);
2261         if (rc < 1 || rc > 2) {
2262                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2263                                 "for crypt_stat session key; expected rc = 1; "
2264                                 "got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
2265                                 rc, key_rec->enc_key_size);
2266                 rc = -ENOMEM;
2267                 goto out;
2268         }
2269         rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
2270                                  dst_sg, 2);
2271         if (rc < 1 || rc > 2) {
2272                 ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
2273                                 "for crypt_stat encrypted session key; "
2274                                 "expected rc = 1; got rc = [%d]. "
2275                                 "key_rec->enc_key_size = [%zd]\n", rc,
2276                                 key_rec->enc_key_size);
2277                 rc = -ENOMEM;
2278                 goto out;
2279         }
2280         mutex_lock(tfm_mutex);
2281         rc = crypto_blkcipher_setkey(desc.tfm, session_key_encryption_key,
2282                                      crypt_stat->key_size);
2283         if (rc < 0) {
2284                 mutex_unlock(tfm_mutex);
2285                 ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
2286                                 "context; rc = [%d]\n", rc);
2287                 goto out;
2288         }
2289         rc = 0;
2290         ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
2291                         crypt_stat->key_size);
2292         rc = crypto_blkcipher_encrypt(&desc, dst_sg, src_sg,
2293                                       (*key_rec).enc_key_size);
2294         mutex_unlock(tfm_mutex);
2295         if (rc) {
2296                 printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
2297                 goto out;
2298         }
2299         ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
2300         if (ecryptfs_verbosity > 0) {
2301                 ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
2302                                 key_rec->enc_key_size);
2303                 ecryptfs_dump_hex(key_rec->enc_key,
2304                                   key_rec->enc_key_size);
2305         }
2306 encrypted_session_key_set:
2307         /* This format is inspired by OpenPGP; see RFC 2440
2308          * packet tag 3 */
2309         max_packet_size = (1                         /* Tag 3 identifier */
2310                            + 3                       /* Max Tag 3 packet size */
2311                            + 1                       /* Version */
2312                            + 1                       /* Cipher code */
2313                            + 1                       /* S2K specifier */
2314                            + 1                       /* Hash identifier */
2315                            + ECRYPTFS_SALT_SIZE      /* Salt */
2316                            + 1                       /* Hash iterations */
2317                            + key_rec->enc_key_size); /* Encrypted key size */
2318         if (max_packet_size > (*remaining_bytes)) {
2319                 printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
2320                        "there are only [%td] available\n", max_packet_size,
2321                        (*remaining_bytes));
2322                 rc = -EINVAL;
2323                 goto out;
2324         }
2325         dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
2326         /* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
2327          * to get the number of octets in the actual Tag 3 packet */
2328         rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
2329                                           (max_packet_size - 4),
2330                                           &packet_size_length);
2331         if (rc) {
2332                 printk(KERN_ERR "Error generating tag 3 packet header; cannot "
2333                        "generate packet length. rc = [%d]\n", rc);
2334                 goto out;
2335         }
2336         (*packet_size) += packet_size_length;
2337         dest[(*packet_size)++] = 0x04; /* version 4 */
2338         /* TODO: Break from RFC2440 so that arbitrary ciphers can be
2339          * specified with strings */
2340         cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
2341                                                       crypt_stat->key_size);
2342         if (cipher_code == 0) {
2343                 ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
2344                                 "cipher [%s]\n", crypt_stat->cipher);
2345                 rc = -EINVAL;
2346                 goto out;
2347         }
2348         dest[(*packet_size)++] = cipher_code;
2349         dest[(*packet_size)++] = 0x03;  /* S2K */
2350         dest[(*packet_size)++] = 0x01;  /* MD5 (TODO: parameterize) */
2351         memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
2352                ECRYPTFS_SALT_SIZE);
2353         (*packet_size) += ECRYPTFS_SALT_SIZE;   /* salt */
2354         dest[(*packet_size)++] = 0x60;  /* hash iterations (65536) */
2355         memcpy(&dest[(*packet_size)], key_rec->enc_key,
2356                key_rec->enc_key_size);
2357         (*packet_size) += key_rec->enc_key_size;
2358 out:
2359         if (rc)
2360                 (*packet_size) = 0;
2361         else
2362                 (*remaining_bytes) -= (*packet_size);
2363         return rc;
2364 }
2365
2366 struct kmem_cache *ecryptfs_key_record_cache;
2367
2368 /**
2369  * ecryptfs_generate_key_packet_set
2370  * @dest_base: Virtual address from which to write the key record set
2371  * @crypt_stat: The cryptographic context from which the
2372  *              authentication tokens will be retrieved
2373  * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
2374  *                   for the global parameters
2375  * @len: The amount written
2376  * @max: The maximum amount of data allowed to be written
2377  *
2378  * Generates a key packet set and writes it to the virtual address
2379  * passed in.
2380  *
2381  * Returns zero on success; non-zero on error.
2382  */
2383 int
2384 ecryptfs_generate_key_packet_set(char *dest_base,
2385                                  struct ecryptfs_crypt_stat *crypt_stat,
2386                                  struct dentry *ecryptfs_dentry, size_t *len,
2387                                  size_t max)
2388 {
2389         struct ecryptfs_auth_tok *auth_tok;
2390         struct key *auth_tok_key = NULL;
2391         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2392                 &ecryptfs_superblock_to_private(
2393                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
2394         size_t written;
2395         struct ecryptfs_key_record *key_rec;
2396         struct ecryptfs_key_sig *key_sig;
2397         int rc = 0;
2398
2399         (*len) = 0;
2400         mutex_lock(&crypt_stat->keysig_list_mutex);
2401         key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
2402         if (!key_rec) {
2403                 rc = -ENOMEM;
2404                 goto out;
2405         }
2406         list_for_each_entry(key_sig, &crypt_stat->keysig_list,
2407                             crypt_stat_list) {
2408                 memset(key_rec, 0, sizeof(*key_rec));
2409                 rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
2410                                                            &auth_tok,
2411                                                            mount_crypt_stat,
2412                                                            key_sig->keysig);
2413                 if (rc) {
2414                         printk(KERN_WARNING "Unable to retrieve auth tok with "
2415                                "sig = [%s]\n", key_sig->keysig);
2416                         rc = process_find_global_auth_tok_for_sig_err(rc);
2417                         goto out_free;
2418                 }
2419                 if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
2420                         rc = write_tag_3_packet((dest_base + (*len)),
2421                                                 &max, auth_tok,
2422                                                 crypt_stat, key_rec,
2423                                                 &written);
2424                         if (rc) {
2425                                 ecryptfs_printk(KERN_WARNING, "Error "
2426                                                 "writing tag 3 packet\n");
2427                                 goto out_free;
2428                         }
2429                         (*len) += written;
2430                         /* Write auth tok signature packet */
2431                         rc = write_tag_11_packet((dest_base + (*len)), &max,
2432                                                  key_rec->sig,
2433                                                  ECRYPTFS_SIG_SIZE, &written);
2434                         if (rc) {
2435                                 ecryptfs_printk(KERN_ERR, "Error writing "
2436                                                 "auth tok signature packet\n");
2437                                 goto out_free;
2438                         }
2439                         (*len) += written;
2440                 } else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
2441                         rc = write_tag_1_packet(dest_base + (*len),
2442                                                 &max, auth_tok,
2443                                                 crypt_stat, key_rec, &written);
2444                         if (rc) {
2445                                 ecryptfs_printk(KERN_WARNING, "Error "
2446                                                 "writing tag 1 packet\n");
2447                                 goto out_free;
2448                         }
2449                         (*len) += written;
2450                 } else {
2451                         ecryptfs_printk(KERN_WARNING, "Unsupported "
2452                                         "authentication token type\n");
2453                         rc = -EINVAL;
2454                         goto out_free;
2455                 }
2456                 up_write(&(auth_tok_key->sem));
2457                 key_put(auth_tok_key);
2458                 auth_tok_key = NULL;
2459         }
2460         if (likely(max > 0)) {
2461                 dest_base[(*len)] = 0x00;
2462         } else {
2463                 ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
2464                 rc = -EIO;
2465         }
2466 out_free:
2467         kmem_cache_free(ecryptfs_key_record_cache, key_rec);
2468 out:
2469         if (rc)
2470                 (*len) = 0;
2471         if (auth_tok_key) {
2472                 up_write(&(auth_tok_key->sem));
2473                 key_put(auth_tok_key);
2474         }
2475
2476         mutex_unlock(&crypt_stat->keysig_list_mutex);
2477         return rc;
2478 }
2479
2480 struct kmem_cache *ecryptfs_key_sig_cache;
2481
2482 int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
2483 {
2484         struct ecryptfs_key_sig *new_key_sig;
2485
2486         new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
2487         if (!new_key_sig) {
2488                 printk(KERN_ERR
2489                        "Error allocating from ecryptfs_key_sig_cache\n");
2490                 return -ENOMEM;
2491         }
2492         memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
2493         new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2494         /* Caller must hold keysig_list_mutex */
2495         list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
2496
2497         return 0;
2498 }
2499
2500 struct kmem_cache *ecryptfs_global_auth_tok_cache;
2501
2502 int
2503 ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2504                              char *sig, u32 global_auth_tok_flags)
2505 {
2506         struct ecryptfs_global_auth_tok *new_auth_tok;
2507         int rc = 0;
2508
2509         new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
2510                                         GFP_KERNEL);
2511         if (!new_auth_tok) {
2512                 rc = -ENOMEM;
2513                 printk(KERN_ERR "Error allocating from "
2514                        "ecryptfs_global_auth_tok_cache\n");
2515                 goto out;
2516         }
2517         memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
2518         new_auth_tok->flags = global_auth_tok_flags;
2519         new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
2520         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
2521         list_add(&new_auth_tok->mount_crypt_stat_list,
2522                  &mount_crypt_stat->global_auth_tok_list);
2523         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
2524 out:
2525         return rc;
2526 }
2527