4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.gnu.org/licenses/gpl-2.0.html
23 * Copyright (c) 2019, 2020, Whamcloud.
26 * This file is part of Lustre, http://www.lustre.org/
29 #include "llite_internal.h"
31 #ifdef HAVE_LUSTRE_CRYPTO
32 #include <libcfs/libcfs_crypto.h>
34 static int ll_get_context(struct inode *inode, void *ctx, size_t len)
38 /* Get enc context xattr directly instead of going through the VFS,
39 * as there is no xattr handler for "encryption.".
41 rc = ll_xattr_list(inode, xattr_for_enc(inode),
42 XATTR_ENCRYPTION_T, ctx, len, OBD_MD_FLXATTR);
44 /* used as encryption unit size */
45 if (S_ISREG(inode->i_mode))
46 inode->i_blkbits = LUSTRE_ENCRYPTION_BLOCKBITS;
50 int ll_set_encflags(struct inode *inode, void *encctx, __u32 encctxlen,
53 unsigned int ext_flags;
56 /* used as encryption unit size */
57 if (S_ISREG(inode->i_mode))
58 inode->i_blkbits = LUSTRE_ENCRYPTION_BLOCKBITS;
59 ext_flags = ll_inode_to_ext_flags(inode->i_flags) | LUSTRE_ENCRYPT_FL;
60 ll_update_inode_flags(inode, ext_flags);
62 if (encctx && encctxlen)
63 rc = ll_xattr_cache_insert(inode,
69 return preload ? llcrypt_get_encryption_info(inode) : 0;
72 /* ll_set_context has 2 distinct behaviors, depending on the value of inode
75 * passed fs_data is a struct md_op_data *. We need to store enc ctx in
76 * op_data, so that it will be sent along to the server with the request that
77 * the caller is preparing, thus saving a setxattr request.
78 * - inode is not NULL:
79 * normal case, letting proceed with setxattr operation.
80 * This use case should only be used when explicitly setting a new encryption
81 * policy on an existing, empty directory.
83 static int ll_set_context(struct inode *inode, const void *ctx, size_t len,
86 struct ptlrpc_request *req = NULL;
87 struct ll_sb_info *sbi;
91 struct md_op_data *op_data = (struct md_op_data *)fs_data;
96 OBD_ALLOC(op_data->op_file_encctx, len);
97 if (op_data->op_file_encctx == NULL)
99 op_data->op_file_encctx_size = len;
100 memcpy(op_data->op_file_encctx, ctx, len);
104 /* Encrypting the root directory is not allowed */
105 if (is_root_inode(inode))
108 sbi = ll_i2sbi(inode);
109 /* Send setxattr request to lower layers directly instead of going
110 * through the VFS, as there is no xattr handler for "encryption.".
112 rc = md_setxattr(sbi->ll_md_exp, ll_inode2fid(inode),
113 OBD_MD_FLXATTR, xattr_for_enc(inode),
114 ctx, len, XATTR_CREATE, ll_i2suppgid(inode), &req);
117 ptlrpc_req_finished(req);
119 return ll_set_encflags(inode, (void *)ctx, len, false);
123 * ll_file_open_encrypt() - overlay to llcrypt_file_open
124 * @inode: the inode being opened
125 * @filp: the struct file being set up
127 * This overlay function is necessary to handle encrypted file open without
128 * the key. We allow this access pattern to applications that know what they
129 * are doing, by using the specific flag O_FILE_ENC.
130 * This flag is only compatible with O_DIRECT IOs, to make sure ciphertext
131 * data is wiped from page cache once IOs are finished.
133 int ll_file_open_encrypt(struct inode *inode, struct file *filp)
137 rc = llcrypt_file_open(inode, filp);
138 if (likely(rc != -ENOKEY))
142 (filp->f_flags & O_FILE_ENC) == O_FILE_ENC &&
143 filp->f_flags & O_DIRECT)
144 /* allow file open with O_FILE_ENC flag when we have O_DIRECT */
150 void llcrypt_free_ctx(void *encctx, __u32 size)
153 OBD_FREE(encctx, size);
156 #ifdef HAVE_FSCRYPT_DUMMY_CONTEXT_ENABLED
157 bool ll_sb_has_test_dummy_encryption(struct super_block *sb)
159 struct ll_sb_info *sbi = s2lsi(sb)->lsi_llsbi;
162 unlikely(test_bit(LL_SBI_TEST_DUMMY_ENCRYPTION, sbi->ll_flags)) :
166 static bool ll_dummy_context(struct inode *inode)
168 return ll_sb_has_test_dummy_encryption(inode->i_sb);
171 static const union llcrypt_context *
172 ll_get_dummy_context(struct super_block *sb)
174 struct lustre_sb_info *lsi = s2lsi(sb);
176 return lsi ? lsi->lsi_dummy_enc_ctx.ctx : NULL;
179 bool ll_sb_has_test_dummy_encryption(struct super_block *sb)
181 return ll_get_dummy_context(sb) != NULL;
185 bool ll_sbi_has_encrypt(struct ll_sb_info *sbi)
187 return test_bit(LL_SBI_ENCRYPT, sbi->ll_flags);
190 void ll_sbi_set_encrypt(struct ll_sb_info *sbi, bool set)
193 set_bit(LL_SBI_ENCRYPT, sbi->ll_flags);
195 clear_bit(LL_SBI_ENCRYPT, sbi->ll_flags);
196 clear_bit(LL_SBI_TEST_DUMMY_ENCRYPTION, sbi->ll_flags);
200 bool ll_sbi_has_name_encrypt(struct ll_sb_info *sbi)
202 return test_bit(LL_SBI_ENCRYPT_NAME, sbi->ll_flags);
205 void ll_sbi_set_name_encrypt(struct ll_sb_info *sbi, bool set)
208 set_bit(LL_SBI_ENCRYPT_NAME, sbi->ll_flags);
210 clear_bit(LL_SBI_ENCRYPT_NAME, sbi->ll_flags);
213 static bool ll_empty_dir(struct inode *inode)
215 /* used by llcrypt_ioctl_set_policy(), because a policy can only be set
218 /* Here we choose to return true, meaning we always call .set_context.
219 * Then we rely on server side, with mdd_fix_attr() that calls
220 * mdd_dir_is_empty() when setting encryption flag on directory.
226 * ll_setup_filename() - overlay to llcrypt_setup_filename
227 * @dir: the directory that will be searched
228 * @iname: the user-provided filename being searched for
229 * @lookup: 1 if we're allowed to proceed without the key because it's
230 * ->lookup() or we're finding the dir_entry for deletion; 0 if we cannot
231 * proceed without the key because we're going to create the dir_entry.
232 * @fname: the filename information to be filled in
233 * @fid: fid retrieved from user-provided filename
235 * This overlay function is necessary to properly encode @fname after
236 * encryption, as it will be sent over the wire.
237 * This overlay function is also necessary to handle the case of operations
238 * carried out without the key. Normally llcrypt makes use of digested names in
239 * that case. Having a digested name works for local file systems that can call
240 * llcrypt_match_name(), but Lustre server side is not aware of encryption.
241 * So for keyless @lookup operations on long names, for Lustre we choose to
242 * present to users the encoded struct ll_digest_filename, instead of a digested
243 * name. FID and name hash can then easily be extracted and put into the
244 * requests sent to servers.
246 int ll_setup_filename(struct inode *dir, const struct qstr *iname,
247 int lookup, struct llcrypt_name *fname,
254 if (fid && IS_ENCRYPTED(dir) && !llcrypt_has_encryption_key(dir) &&
255 iname->name[0] == '_')
258 dname.name = iname->name + digested;
259 dname.len = iname->len - digested;
266 rc = llcrypt_setup_filename(dir, &dname, lookup, fname);
267 if (rc == -ENOENT && lookup) {
268 if (((is_root_inode(dir) &&
269 iname->len == strlen(dot_fscrypt_name) &&
270 strncmp(iname->name, dot_fscrypt_name, iname->len) == 0) ||
271 (!llcrypt_has_encryption_key(dir) &&
272 unlikely(filename_is_volatile(iname->name,
273 iname->len, NULL))))) {
274 /* In case of subdir mount of an encrypted directory,
275 * we allow lookup of /.fscrypt directory.
277 /* For purpose of migration or mirroring without enc key
278 * we allow lookup of volatile file without enc context.
280 memset(fname, 0, sizeof(struct llcrypt_name));
281 fname->disk_name.name = (unsigned char *)iname->name;
282 fname->disk_name.len = iname->len;
284 } else if (!llcrypt_has_encryption_key(dir)) {
292 /* Without the key, for long names user should have struct
293 * ll_digest_filename representation of the dentry instead of
294 * the name. So make sure it is valid, return fid and put
295 * excerpt of cipher text name in disk_name.
297 struct ll_digest_filename *digest;
299 if (fname->crypto_buf.len < sizeof(struct ll_digest_filename)) {
303 digest = (struct ll_digest_filename *)fname->disk_name.name;
304 *fid = digest->ldf_fid;
305 if (!fid_is_sane(fid)) {
309 fname->disk_name.name = digest->ldf_excerpt;
310 fname->disk_name.len = sizeof(digest->ldf_excerpt);
312 if (IS_ENCRYPTED(dir) &&
313 !name_is_dot_or_dotdot(fname->disk_name.name,
314 fname->disk_name.len)) {
315 int presented_len = critical_chars(fname->disk_name.name,
316 fname->disk_name.len);
319 buf = kmalloc(presented_len + 1, GFP_NOFS);
325 if (presented_len == fname->disk_name.len)
326 memcpy(buf, fname->disk_name.name, presented_len);
328 critical_encode(fname->disk_name.name,
329 fname->disk_name.len, buf);
330 buf[presented_len] = '\0';
331 kfree(fname->crypto_buf.name);
332 fname->crypto_buf.name = buf;
333 fname->crypto_buf.len = presented_len;
334 fname->disk_name.name = fname->crypto_buf.name;
335 fname->disk_name.len = fname->crypto_buf.len;
341 llcrypt_free_filename(fname);
346 * ll_fname_disk_to_usr() - overlay to llcrypt_fname_disk_to_usr
347 * @inode: the inode to convert name
348 * @hash: major hash for inode
349 * @minor_hash: minor hash for inode
350 * @iname: the user-provided filename needing conversion
351 * @oname: the filename information to be filled in
352 * @fid: the user-provided fid for filename
354 * The caller must have allocated sufficient memory for the @oname string.
356 * This overlay function is necessary to properly decode @iname before
357 * decryption, as it comes from the wire.
358 * This overlay function is also necessary to handle the case of operations
359 * carried out without the key. Normally llcrypt makes use of digested names in
360 * that case. Having a digested name works for local file systems that can call
361 * llcrypt_match_name(), but Lustre server side is not aware of encryption.
362 * So for keyless @lookup operations on long names, for Lustre we choose to
363 * present to users the encoded struct ll_digest_filename, instead of a digested
364 * name. FID and name hash can then easily be extracted and put into the
365 * requests sent to servers.
367 int ll_fname_disk_to_usr(struct inode *inode,
368 u32 hash, u32 minor_hash,
369 struct llcrypt_str *iname, struct llcrypt_str *oname,
372 struct llcrypt_str lltr = LLTR_INIT(iname->name, iname->len);
373 struct ll_digest_filename digest;
378 if (IS_ENCRYPTED(inode)) {
379 if (!name_is_dot_or_dotdot(lltr.name, lltr.len) &&
380 strnchr(lltr.name, lltr.len, '=')) {
381 /* Only proceed to critical decode if
382 * iname contains espace char '='.
386 buf = kmalloc(len, GFP_NOFS);
390 len = critical_decode(lltr.name, len, buf);
394 if (lltr.len > LL_CRYPTO_BLOCK_SIZE * 2 &&
395 !llcrypt_has_encryption_key(inode) &&
396 llcrypt_policy_has_filename_enc(inode)) {
398 /* Without the key for long names, set the dentry name
399 * to the representing struct ll_digest_filename. It
400 * will be encoded by llcrypt for display, and will
401 * enable further lookup requests.
405 digest.ldf_fid = *fid;
406 memcpy(digest.ldf_excerpt,
407 LLCRYPT_EXTRACT_DIGEST(lltr.name, lltr.len),
408 sizeof(digest.ldf_excerpt));
410 lltr.name = (char *)&digest;
411 lltr.len = sizeof(digest);
413 oname->name[0] = '_';
414 oname->name = oname->name + 1;
419 rc = llcrypt_fname_disk_to_usr(inode, hash, minor_hash, &lltr, oname);
422 oname->name = oname->name - digested;
423 oname->len = oname->len + digested;
428 /* Copied from llcrypt_d_revalidate, as it is not exported */
430 * Validate dentries in encrypted directories to make sure we aren't potentially
431 * caching stale dentries after a key has been added.
433 int ll_revalidate_d_crypto(struct dentry *dentry, unsigned int flags)
440 * Plaintext names are always valid, since llcrypt doesn't support
441 * reverting to ciphertext names without evicting the directory's inode
442 * -- which implies eviction of the dentries in the directory.
444 if (!llcrypt_is_nokey_name(dentry))
448 * Ciphertext name; valid if the directory's key is still unavailable.
450 * Although llcrypt forbids rename() on ciphertext names, we still must
451 * use dget_parent() here rather than use ->d_parent directly. That's
452 * because a corrupted fs image may contain directory hard links, which
453 * the VFS handles by moving the directory's dentry tree in the dcache
454 * each time ->lookup() finds the directory and it already has a dentry
455 * elsewhere. Thus ->d_parent can be changing, and we must safely grab
456 * a reference to some ->d_parent to prevent it from being freed.
459 if (flags & LOOKUP_RCU)
462 dir = dget_parent(dentry);
463 err = llcrypt_get_encryption_info(d_inode(dir));
464 valid = !llcrypt_has_encryption_key(d_inode(dir));
473 const struct llcrypt_operations lustre_cryptops = {
474 .key_prefix = "lustre:",
475 .get_context = ll_get_context,
476 .set_context = ll_set_context,
477 #ifdef HAVE_FSCRYPT_DUMMY_CONTEXT_ENABLED
478 .dummy_context = ll_dummy_context,
480 .get_dummy_context = ll_get_dummy_context,
482 .empty_dir = ll_empty_dir,
483 .max_namelen = NAME_MAX,
485 #else /* !HAVE_LUSTRE_CRYPTO */
486 int ll_set_encflags(struct inode *inode, void *encctx, __u32 encctxlen,
492 int ll_file_open_encrypt(struct inode *inode, struct file *filp)
494 return llcrypt_file_open(inode, filp);
497 void llcrypt_free_ctx(void *encctx, __u32 size)
501 bool ll_sb_has_test_dummy_encryption(struct super_block *sb)
506 bool ll_sbi_has_encrypt(struct ll_sb_info *sbi)
511 void ll_sbi_set_encrypt(struct ll_sb_info *sbi, bool set)
515 bool ll_sbi_has_name_encrypt(struct ll_sb_info *sbi)
520 void ll_sbi_set_name_encrypt(struct ll_sb_info *sbi, bool set)
524 int ll_setup_filename(struct inode *dir, const struct qstr *iname,
525 int lookup, struct llcrypt_name *fname,
534 return llcrypt_setup_filename(dir, iname, lookup, fname);
537 int ll_fname_disk_to_usr(struct inode *inode,
538 u32 hash, u32 minor_hash,
539 struct llcrypt_str *iname, struct llcrypt_str *oname,
542 return llcrypt_fname_disk_to_usr(inode, hash, minor_hash, iname, oname);
545 int ll_revalidate_d_crypto(struct dentry *dentry, unsigned int flags)