1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * The base64 encode/decode code was copied from fscrypt:
4 * Copyright (C) 2015, Google, Inc.
5 * Copyright (C) 2015, Motorola Mobility
6 * Written by Uday Savagaonkar, 2014.
7 * Modified by Jaegeuk Kim, 2015.
8 */
9 #include <linux/ceph/ceph_debug.h>
10 #include <linux/xattr.h>
11 #include <linux/fscrypt.h>
12 #include <linux/ceph/striper.h>
13
14 #include "super.h"
15 #include "mds_client.h"
16 #include "crypto.h"
17
18 /*
19 * The base64url encoding used by fscrypt includes the '_' character, which may
20 * cause problems in snapshot names (which can not start with '_'). Thus, we
21 * used the base64 encoding defined for IMAP mailbox names (RFC 3501) instead,
22 * which replaces '-' and '_' by '+' and ','.
23 */
24 static const char base64_table[65] =
25 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
26
ceph_base64_encode(const u8 * src,int srclen,char * dst)27 int ceph_base64_encode(const u8 *src, int srclen, char *dst)
28 {
29 u32 ac = 0;
30 int bits = 0;
31 int i;
32 char *cp = dst;
33
34 for (i = 0; i < srclen; i++) {
35 ac = (ac << 8) | src[i];
36 bits += 8;
37 do {
38 bits -= 6;
39 *cp++ = base64_table[(ac >> bits) & 0x3f];
40 } while (bits >= 6);
41 }
42 if (bits)
43 *cp++ = base64_table[(ac << (6 - bits)) & 0x3f];
44 return cp - dst;
45 }
46
ceph_base64_decode(const char * src,int srclen,u8 * dst)47 int ceph_base64_decode(const char *src, int srclen, u8 *dst)
48 {
49 u32 ac = 0;
50 int bits = 0;
51 int i;
52 u8 *bp = dst;
53
54 for (i = 0; i < srclen; i++) {
55 const char *p = strchr(base64_table, src[i]);
56
57 if (p == NULL || src[i] == 0)
58 return -1;
59 ac = (ac << 6) | (p - base64_table);
60 bits += 6;
61 if (bits >= 8) {
62 bits -= 8;
63 *bp++ = (u8)(ac >> bits);
64 }
65 }
66 if (ac & ((1 << bits) - 1))
67 return -1;
68 return bp - dst;
69 }
70
ceph_crypt_get_context(struct inode * inode,void * ctx,size_t len)71 static int ceph_crypt_get_context(struct inode *inode, void *ctx, size_t len)
72 {
73 struct ceph_inode_info *ci = ceph_inode(inode);
74 struct ceph_fscrypt_auth *cfa = (struct ceph_fscrypt_auth *)ci->fscrypt_auth;
75 u32 ctxlen;
76
77 /* Non existent or too short? */
78 if (!cfa || (ci->fscrypt_auth_len < (offsetof(struct ceph_fscrypt_auth, cfa_blob) + 1)))
79 return -ENOBUFS;
80
81 /* Some format we don't recognize? */
82 if (le32_to_cpu(cfa->cfa_version) != CEPH_FSCRYPT_AUTH_VERSION)
83 return -ENOBUFS;
84
85 ctxlen = le32_to_cpu(cfa->cfa_blob_len);
86 if (len < ctxlen)
87 return -ERANGE;
88
89 memcpy(ctx, cfa->cfa_blob, ctxlen);
90 return ctxlen;
91 }
92
ceph_crypt_set_context(struct inode * inode,const void * ctx,size_t len,void * fs_data)93 static int ceph_crypt_set_context(struct inode *inode, const void *ctx,
94 size_t len, void *fs_data)
95 {
96 int ret;
97 struct iattr attr = { };
98 struct ceph_iattr cia = { };
99 struct ceph_fscrypt_auth *cfa;
100
101 WARN_ON_ONCE(fs_data);
102
103 if (len > FSCRYPT_SET_CONTEXT_MAX_SIZE)
104 return -EINVAL;
105
106 cfa = kzalloc(sizeof(*cfa), GFP_KERNEL);
107 if (!cfa)
108 return -ENOMEM;
109
110 cfa->cfa_version = cpu_to_le32(CEPH_FSCRYPT_AUTH_VERSION);
111 cfa->cfa_blob_len = cpu_to_le32(len);
112 memcpy(cfa->cfa_blob, ctx, len);
113
114 cia.fscrypt_auth = cfa;
115
116 ret = __ceph_setattr(&nop_mnt_idmap, inode, &attr, &cia);
117 if (ret == 0)
118 inode_set_flags(inode, S_ENCRYPTED, S_ENCRYPTED);
119 kfree(cia.fscrypt_auth);
120 return ret;
121 }
122
ceph_crypt_empty_dir(struct inode * inode)123 static bool ceph_crypt_empty_dir(struct inode *inode)
124 {
125 struct ceph_inode_info *ci = ceph_inode(inode);
126
127 return ci->i_rsubdirs + ci->i_rfiles == 1;
128 }
129
ceph_get_dummy_policy(struct super_block * sb)130 static const union fscrypt_policy *ceph_get_dummy_policy(struct super_block *sb)
131 {
132 return ceph_sb_to_fs_client(sb)->fsc_dummy_enc_policy.policy;
133 }
134
135 static struct fscrypt_operations ceph_fscrypt_ops = {
136 .needs_bounce_pages = 1,
137 .get_context = ceph_crypt_get_context,
138 .set_context = ceph_crypt_set_context,
139 .get_dummy_policy = ceph_get_dummy_policy,
140 .empty_dir = ceph_crypt_empty_dir,
141 };
142
ceph_fscrypt_set_ops(struct super_block * sb)143 void ceph_fscrypt_set_ops(struct super_block *sb)
144 {
145 fscrypt_set_ops(sb, &ceph_fscrypt_ops);
146 }
147
ceph_fscrypt_free_dummy_policy(struct ceph_fs_client * fsc)148 void ceph_fscrypt_free_dummy_policy(struct ceph_fs_client *fsc)
149 {
150 fscrypt_free_dummy_policy(&fsc->fsc_dummy_enc_policy);
151 }
152
ceph_fscrypt_prepare_context(struct inode * dir,struct inode * inode,struct ceph_acl_sec_ctx * as)153 int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode,
154 struct ceph_acl_sec_ctx *as)
155 {
156 int ret, ctxsize;
157 bool encrypted = false;
158 struct ceph_inode_info *ci = ceph_inode(inode);
159
160 ret = fscrypt_prepare_new_inode(dir, inode, &encrypted);
161 if (ret)
162 return ret;
163 if (!encrypted)
164 return 0;
165
166 as->fscrypt_auth = kzalloc(sizeof(*as->fscrypt_auth), GFP_KERNEL);
167 if (!as->fscrypt_auth)
168 return -ENOMEM;
169
170 ctxsize = fscrypt_context_for_new_inode(as->fscrypt_auth->cfa_blob,
171 inode);
172 if (ctxsize < 0)
173 return ctxsize;
174
175 as->fscrypt_auth->cfa_version = cpu_to_le32(CEPH_FSCRYPT_AUTH_VERSION);
176 as->fscrypt_auth->cfa_blob_len = cpu_to_le32(ctxsize);
177
178 WARN_ON_ONCE(ci->fscrypt_auth);
179 kfree(ci->fscrypt_auth);
180 ci->fscrypt_auth_len = ceph_fscrypt_auth_len(as->fscrypt_auth);
181 ci->fscrypt_auth = kmemdup(as->fscrypt_auth, ci->fscrypt_auth_len,
182 GFP_KERNEL);
183 if (!ci->fscrypt_auth)
184 return -ENOMEM;
185
186 inode->i_flags |= S_ENCRYPTED;
187
188 return 0;
189 }
190
ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request * req,struct ceph_acl_sec_ctx * as)191 void ceph_fscrypt_as_ctx_to_req(struct ceph_mds_request *req,
192 struct ceph_acl_sec_ctx *as)
193 {
194 swap(req->r_fscrypt_auth, as->fscrypt_auth);
195 }
196
197 /*
198 * User-created snapshots can't start with '_'. Snapshots that start with this
199 * character are special (hint: there aren't real snapshots) and use the
200 * following format:
201 *
202 * _<SNAPSHOT-NAME>_<INODE-NUMBER>
203 *
204 * where:
205 * - <SNAPSHOT-NAME> - the real snapshot name that may need to be decrypted,
206 * - <INODE-NUMBER> - the inode number (in decimal) for the actual snapshot
207 *
208 * This function parses these snapshot names and returns the inode
209 * <INODE-NUMBER>. 'name_len' will also bet set with the <SNAPSHOT-NAME>
210 * length.
211 */
parse_longname(const struct inode * parent,const char * name,int * name_len)212 static struct inode *parse_longname(const struct inode *parent,
213 const char *name, int *name_len)
214 {
215 struct ceph_client *cl = ceph_inode_to_client(parent);
216 struct inode *dir = NULL;
217 struct ceph_vino vino = { .snap = CEPH_NOSNAP };
218 char *inode_number;
219 char *name_end;
220 int orig_len = *name_len;
221 int ret = -EIO;
222
223 /* Skip initial '_' */
224 name++;
225 name_end = strrchr(name, '_');
226 if (!name_end) {
227 doutc(cl, "failed to parse long snapshot name: %s\n", name);
228 return ERR_PTR(-EIO);
229 }
230 *name_len = (name_end - name);
231 if (*name_len <= 0) {
232 pr_err_client(cl, "failed to parse long snapshot name\n");
233 return ERR_PTR(-EIO);
234 }
235
236 /* Get the inode number */
237 inode_number = kmemdup_nul(name_end + 1,
238 orig_len - *name_len - 2,
239 GFP_KERNEL);
240 if (!inode_number)
241 return ERR_PTR(-ENOMEM);
242 ret = kstrtou64(inode_number, 10, &vino.ino);
243 if (ret) {
244 doutc(cl, "failed to parse inode number: %s\n", name);
245 dir = ERR_PTR(ret);
246 goto out;
247 }
248
249 /* And finally the inode */
250 dir = ceph_find_inode(parent->i_sb, vino);
251 if (!dir) {
252 /* This can happen if we're not mounting cephfs on the root */
253 dir = ceph_get_inode(parent->i_sb, vino, NULL);
254 if (IS_ERR(dir))
255 doutc(cl, "can't find inode %s (%s)\n", inode_number, name);
256 }
257
258 out:
259 kfree(inode_number);
260 return dir;
261 }
262
ceph_encode_encrypted_dname(struct inode * parent,struct qstr * d_name,char * buf)263 int ceph_encode_encrypted_dname(struct inode *parent, struct qstr *d_name,
264 char *buf)
265 {
266 struct ceph_client *cl = ceph_inode_to_client(parent);
267 struct inode *dir = parent;
268 struct qstr iname;
269 u32 len;
270 int name_len;
271 int elen;
272 int ret;
273 u8 *cryptbuf = NULL;
274
275 iname.name = d_name->name;
276 name_len = d_name->len;
277
278 /* Handle the special case of snapshot names that start with '_' */
279 if ((ceph_snap(dir) == CEPH_SNAPDIR) && (name_len > 0) &&
280 (iname.name[0] == '_')) {
281 dir = parse_longname(parent, iname.name, &name_len);
282 if (IS_ERR(dir))
283 return PTR_ERR(dir);
284 iname.name++; /* skip initial '_' */
285 }
286 iname.len = name_len;
287
288 if (!fscrypt_has_encryption_key(dir)) {
289 memcpy(buf, d_name->name, d_name->len);
290 elen = d_name->len;
291 goto out;
292 }
293
294 /*
295 * Convert cleartext d_name to ciphertext. If result is longer than
296 * CEPH_NOHASH_NAME_MAX, sha256 the remaining bytes
297 *
298 * See: fscrypt_setup_filename
299 */
300 if (!fscrypt_fname_encrypted_size(dir, iname.len, NAME_MAX, &len)) {
301 elen = -ENAMETOOLONG;
302 goto out;
303 }
304
305 /* Allocate a buffer appropriate to hold the result */
306 cryptbuf = kmalloc(len > CEPH_NOHASH_NAME_MAX ? NAME_MAX : len,
307 GFP_KERNEL);
308 if (!cryptbuf) {
309 elen = -ENOMEM;
310 goto out;
311 }
312
313 ret = fscrypt_fname_encrypt(dir, &iname, cryptbuf, len);
314 if (ret) {
315 elen = ret;
316 goto out;
317 }
318
319 /* hash the end if the name is long enough */
320 if (len > CEPH_NOHASH_NAME_MAX) {
321 u8 hash[SHA256_DIGEST_SIZE];
322 u8 *extra = cryptbuf + CEPH_NOHASH_NAME_MAX;
323
324 /*
325 * hash the extra bytes and overwrite crypttext beyond that
326 * point with it
327 */
328 sha256(extra, len - CEPH_NOHASH_NAME_MAX, hash);
329 memcpy(extra, hash, SHA256_DIGEST_SIZE);
330 len = CEPH_NOHASH_NAME_MAX + SHA256_DIGEST_SIZE;
331 }
332
333 /* base64 encode the encrypted name */
334 elen = ceph_base64_encode(cryptbuf, len, buf);
335 doutc(cl, "base64-encoded ciphertext name = %.*s\n", elen, buf);
336
337 /* To understand the 240 limit, see CEPH_NOHASH_NAME_MAX comments */
338 WARN_ON(elen > 240);
339 if ((elen > 0) && (dir != parent)) {
340 char tmp_buf[NAME_MAX];
341
342 elen = snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld",
343 elen, buf, dir->i_ino);
344 memcpy(buf, tmp_buf, elen);
345 }
346
347 out:
348 kfree(cryptbuf);
349 if (dir != parent) {
350 if ((dir->i_state & I_NEW))
351 discard_new_inode(dir);
352 else
353 iput(dir);
354 }
355 return elen;
356 }
357
ceph_encode_encrypted_fname(struct inode * parent,struct dentry * dentry,char * buf)358 int ceph_encode_encrypted_fname(struct inode *parent, struct dentry *dentry,
359 char *buf)
360 {
361 WARN_ON_ONCE(!fscrypt_has_encryption_key(parent));
362
363 return ceph_encode_encrypted_dname(parent, &dentry->d_name, buf);
364 }
365
366 /**
367 * ceph_fname_to_usr - convert a filename for userland presentation
368 * @fname: ceph_fname to be converted
369 * @tname: temporary name buffer to use for conversion (may be NULL)
370 * @oname: where converted name should be placed
371 * @is_nokey: set to true if key wasn't available during conversion (may be NULL)
372 *
373 * Given a filename (usually from the MDS), format it for presentation to
374 * userland. If @parent is not encrypted, just pass it back as-is.
375 *
376 * Otherwise, base64 decode the string, and then ask fscrypt to format it
377 * for userland presentation.
378 *
379 * Returns 0 on success or negative error code on error.
380 */
ceph_fname_to_usr(const struct ceph_fname * fname,struct fscrypt_str * tname,struct fscrypt_str * oname,bool * is_nokey)381 int ceph_fname_to_usr(const struct ceph_fname *fname, struct fscrypt_str *tname,
382 struct fscrypt_str *oname, bool *is_nokey)
383 {
384 struct inode *dir = fname->dir;
385 struct fscrypt_str _tname = FSTR_INIT(NULL, 0);
386 struct fscrypt_str iname;
387 char *name = fname->name;
388 int name_len = fname->name_len;
389 int ret;
390
391 /* Sanity check that the resulting name will fit in the buffer */
392 if (fname->name_len > NAME_MAX || fname->ctext_len > NAME_MAX)
393 return -EIO;
394
395 /* Handle the special case of snapshot names that start with '_' */
396 if ((ceph_snap(dir) == CEPH_SNAPDIR) && (name_len > 0) &&
397 (name[0] == '_')) {
398 dir = parse_longname(dir, name, &name_len);
399 if (IS_ERR(dir))
400 return PTR_ERR(dir);
401 name++; /* skip initial '_' */
402 }
403
404 if (!IS_ENCRYPTED(dir)) {
405 oname->name = fname->name;
406 oname->len = fname->name_len;
407 ret = 0;
408 goto out_inode;
409 }
410
411 ret = ceph_fscrypt_prepare_readdir(dir);
412 if (ret)
413 goto out_inode;
414
415 /*
416 * Use the raw dentry name as sent by the MDS instead of
417 * generating a nokey name via fscrypt.
418 */
419 if (!fscrypt_has_encryption_key(dir)) {
420 if (fname->no_copy)
421 oname->name = fname->name;
422 else
423 memcpy(oname->name, fname->name, fname->name_len);
424 oname->len = fname->name_len;
425 if (is_nokey)
426 *is_nokey = true;
427 ret = 0;
428 goto out_inode;
429 }
430
431 if (fname->ctext_len == 0) {
432 int declen;
433
434 if (!tname) {
435 ret = fscrypt_fname_alloc_buffer(NAME_MAX, &_tname);
436 if (ret)
437 goto out_inode;
438 tname = &_tname;
439 }
440
441 declen = ceph_base64_decode(name, name_len, tname->name);
442 if (declen <= 0) {
443 ret = -EIO;
444 goto out;
445 }
446 iname.name = tname->name;
447 iname.len = declen;
448 } else {
449 iname.name = fname->ctext;
450 iname.len = fname->ctext_len;
451 }
452
453 ret = fscrypt_fname_disk_to_usr(dir, 0, 0, &iname, oname);
454 if (!ret && (dir != fname->dir)) {
455 char tmp_buf[CEPH_BASE64_CHARS(NAME_MAX)];
456
457 name_len = snprintf(tmp_buf, sizeof(tmp_buf), "_%.*s_%ld",
458 oname->len, oname->name, dir->i_ino);
459 memcpy(oname->name, tmp_buf, name_len);
460 oname->len = name_len;
461 }
462
463 out:
464 fscrypt_fname_free_buffer(&_tname);
465 out_inode:
466 if (dir != fname->dir) {
467 if ((dir->i_state & I_NEW))
468 discard_new_inode(dir);
469 else
470 iput(dir);
471 }
472 return ret;
473 }
474
475 /**
476 * ceph_fscrypt_prepare_readdir - simple __fscrypt_prepare_readdir() wrapper
477 * @dir: directory inode for readdir prep
478 *
479 * Simple wrapper around __fscrypt_prepare_readdir() that will mark directory as
480 * non-complete if this call results in having the directory unlocked.
481 *
482 * Returns:
483 * 1 - if directory was locked and key is now loaded (i.e. dir is unlocked)
484 * 0 - if directory is still locked
485 * < 0 - if __fscrypt_prepare_readdir() fails
486 */
ceph_fscrypt_prepare_readdir(struct inode * dir)487 int ceph_fscrypt_prepare_readdir(struct inode *dir)
488 {
489 bool had_key = fscrypt_has_encryption_key(dir);
490 int err;
491
492 if (!IS_ENCRYPTED(dir))
493 return 0;
494
495 err = __fscrypt_prepare_readdir(dir);
496 if (err)
497 return err;
498 if (!had_key && fscrypt_has_encryption_key(dir)) {
499 /* directory just got unlocked, mark it as not complete */
500 ceph_dir_clear_complete(dir);
501 return 1;
502 }
503 return 0;
504 }
505
ceph_fscrypt_decrypt_block_inplace(const struct inode * inode,struct page * page,unsigned int len,unsigned int offs,u64 lblk_num)506 int ceph_fscrypt_decrypt_block_inplace(const struct inode *inode,
507 struct page *page, unsigned int len,
508 unsigned int offs, u64 lblk_num)
509 {
510 struct ceph_client *cl = ceph_inode_to_client(inode);
511
512 doutc(cl, "%p %llx.%llx len %u offs %u blk %llu\n", inode,
513 ceph_vinop(inode), len, offs, lblk_num);
514 return fscrypt_decrypt_block_inplace(inode, page, len, offs, lblk_num);
515 }
516
ceph_fscrypt_encrypt_block_inplace(const struct inode * inode,struct page * page,unsigned int len,unsigned int offs,u64 lblk_num,gfp_t gfp_flags)517 int ceph_fscrypt_encrypt_block_inplace(const struct inode *inode,
518 struct page *page, unsigned int len,
519 unsigned int offs, u64 lblk_num,
520 gfp_t gfp_flags)
521 {
522 struct ceph_client *cl = ceph_inode_to_client(inode);
523
524 doutc(cl, "%p %llx.%llx len %u offs %u blk %llu\n", inode,
525 ceph_vinop(inode), len, offs, lblk_num);
526 return fscrypt_encrypt_block_inplace(inode, page, len, offs, lblk_num,
527 gfp_flags);
528 }
529
530 /**
531 * ceph_fscrypt_decrypt_pages - decrypt an array of pages
532 * @inode: pointer to inode associated with these pages
533 * @page: pointer to page array
534 * @off: offset into the file that the read data starts
535 * @len: max length to decrypt
536 *
537 * Decrypt an array of fscrypt'ed pages and return the amount of
538 * data decrypted. Any data in the page prior to the start of the
539 * first complete block in the read is ignored. Any incomplete
540 * crypto blocks at the end of the array are ignored (and should
541 * probably be zeroed by the caller).
542 *
543 * Returns the length of the decrypted data or a negative errno.
544 */
ceph_fscrypt_decrypt_pages(struct inode * inode,struct page ** page,u64 off,int len)545 int ceph_fscrypt_decrypt_pages(struct inode *inode, struct page **page,
546 u64 off, int len)
547 {
548 int i, num_blocks;
549 u64 baseblk = off >> CEPH_FSCRYPT_BLOCK_SHIFT;
550 int ret = 0;
551
552 /*
553 * We can't deal with partial blocks on an encrypted file, so mask off
554 * the last bit.
555 */
556 num_blocks = ceph_fscrypt_blocks(off, len & CEPH_FSCRYPT_BLOCK_MASK);
557
558 /* Decrypt each block */
559 for (i = 0; i < num_blocks; ++i) {
560 int blkoff = i << CEPH_FSCRYPT_BLOCK_SHIFT;
561 int pgidx = blkoff >> PAGE_SHIFT;
562 unsigned int pgoffs = offset_in_page(blkoff);
563 int fret;
564
565 fret = ceph_fscrypt_decrypt_block_inplace(inode, page[pgidx],
566 CEPH_FSCRYPT_BLOCK_SIZE, pgoffs,
567 baseblk + i);
568 if (fret < 0) {
569 if (ret == 0)
570 ret = fret;
571 break;
572 }
573 ret += CEPH_FSCRYPT_BLOCK_SIZE;
574 }
575 return ret;
576 }
577
578 /**
579 * ceph_fscrypt_decrypt_extents: decrypt received extents in given buffer
580 * @inode: inode associated with pages being decrypted
581 * @page: pointer to page array
582 * @off: offset into the file that the data in page[0] starts
583 * @map: pointer to extent array
584 * @ext_cnt: length of extent array
585 *
586 * Given an extent map and a page array, decrypt the received data in-place,
587 * skipping holes. Returns the offset into buffer of end of last decrypted
588 * block.
589 */
ceph_fscrypt_decrypt_extents(struct inode * inode,struct page ** page,u64 off,struct ceph_sparse_extent * map,u32 ext_cnt)590 int ceph_fscrypt_decrypt_extents(struct inode *inode, struct page **page,
591 u64 off, struct ceph_sparse_extent *map,
592 u32 ext_cnt)
593 {
594 struct ceph_client *cl = ceph_inode_to_client(inode);
595 int i, ret = 0;
596 struct ceph_inode_info *ci = ceph_inode(inode);
597 u64 objno, objoff;
598 u32 xlen;
599
600 /* Nothing to do for empty array */
601 if (ext_cnt == 0) {
602 doutc(cl, "%p %llx.%llx empty array, ret 0\n", inode,
603 ceph_vinop(inode));
604 return 0;
605 }
606
607 ceph_calc_file_object_mapping(&ci->i_layout, off, map[0].len,
608 &objno, &objoff, &xlen);
609
610 for (i = 0; i < ext_cnt; ++i) {
611 struct ceph_sparse_extent *ext = &map[i];
612 int pgsoff = ext->off - objoff;
613 int pgidx = pgsoff >> PAGE_SHIFT;
614 int fret;
615
616 if ((ext->off | ext->len) & ~CEPH_FSCRYPT_BLOCK_MASK) {
617 pr_warn_client(cl,
618 "%p %llx.%llx bad encrypted sparse extent "
619 "idx %d off %llx len %llx\n",
620 inode, ceph_vinop(inode), i, ext->off,
621 ext->len);
622 return -EIO;
623 }
624 fret = ceph_fscrypt_decrypt_pages(inode, &page[pgidx],
625 off + pgsoff, ext->len);
626 doutc(cl, "%p %llx.%llx [%d] 0x%llx~0x%llx fret %d\n", inode,
627 ceph_vinop(inode), i, ext->off, ext->len, fret);
628 if (fret < 0) {
629 if (ret == 0)
630 ret = fret;
631 break;
632 }
633 ret = pgsoff + fret;
634 }
635 doutc(cl, "ret %d\n", ret);
636 return ret;
637 }
638
639 /**
640 * ceph_fscrypt_encrypt_pages - encrypt an array of pages
641 * @inode: pointer to inode associated with these pages
642 * @page: pointer to page array
643 * @off: offset into the file that the data starts
644 * @len: max length to encrypt
645 * @gfp: gfp flags to use for allocation
646 *
647 * Decrypt an array of cleartext pages and return the amount of
648 * data encrypted. Any data in the page prior to the start of the
649 * first complete block in the read is ignored. Any incomplete
650 * crypto blocks at the end of the array are ignored.
651 *
652 * Returns the length of the encrypted data or a negative errno.
653 */
ceph_fscrypt_encrypt_pages(struct inode * inode,struct page ** page,u64 off,int len,gfp_t gfp)654 int ceph_fscrypt_encrypt_pages(struct inode *inode, struct page **page, u64 off,
655 int len, gfp_t gfp)
656 {
657 int i, num_blocks;
658 u64 baseblk = off >> CEPH_FSCRYPT_BLOCK_SHIFT;
659 int ret = 0;
660
661 /*
662 * We can't deal with partial blocks on an encrypted file, so mask off
663 * the last bit.
664 */
665 num_blocks = ceph_fscrypt_blocks(off, len & CEPH_FSCRYPT_BLOCK_MASK);
666
667 /* Encrypt each block */
668 for (i = 0; i < num_blocks; ++i) {
669 int blkoff = i << CEPH_FSCRYPT_BLOCK_SHIFT;
670 int pgidx = blkoff >> PAGE_SHIFT;
671 unsigned int pgoffs = offset_in_page(blkoff);
672 int fret;
673
674 fret = ceph_fscrypt_encrypt_block_inplace(inode, page[pgidx],
675 CEPH_FSCRYPT_BLOCK_SIZE, pgoffs,
676 baseblk + i, gfp);
677 if (fret < 0) {
678 if (ret == 0)
679 ret = fret;
680 break;
681 }
682 ret += CEPH_FSCRYPT_BLOCK_SIZE;
683 }
684 return ret;
685 }
686