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, LL_XATTR_NAME_ENCRYPTION_CONTEXT,
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,
64 LL_XATTR_NAME_ENCRYPTION_CONTEXT,
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, LL_XATTR_NAME_ENCRYPTION_CONTEXT,
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 bool ll_sbi_has_test_dummy_encryption(struct ll_sb_info *sbi)
158 return unlikely(test_bit(LL_SBI_TEST_DUMMY_ENCRYPTION, sbi->ll_flags));
161 static bool ll_dummy_context(struct inode *inode)
163 struct ll_sb_info *sbi = ll_i2sbi(inode);
165 return sbi ? ll_sbi_has_test_dummy_encryption(sbi) : false;
168 bool ll_sbi_has_encrypt(struct ll_sb_info *sbi)
170 return test_bit(LL_SBI_ENCRYPT, sbi->ll_flags);
173 void ll_sbi_set_encrypt(struct ll_sb_info *sbi, bool set)
176 set_bit(LL_SBI_ENCRYPT, sbi->ll_flags);
178 clear_bit(LL_SBI_ENCRYPT, sbi->ll_flags);
179 clear_bit(LL_SBI_TEST_DUMMY_ENCRYPTION, sbi->ll_flags);
183 static bool ll_empty_dir(struct inode *inode)
185 /* used by llcrypt_ioctl_set_policy(), because a policy can only be set
188 /* Here we choose to return true, meaning we always call .set_context.
189 * Then we rely on server side, with mdd_fix_attr() that calls
190 * mdd_dir_is_empty() when setting encryption flag on directory.
196 * ll_setup_filename() - overlay to llcrypt_setup_filename
197 * @dir: the directory that will be searched
198 * @iname: the user-provided filename being searched for
199 * @lookup: 1 if we're allowed to proceed without the key because it's
200 * ->lookup() or we're finding the dir_entry for deletion; 0 if we cannot
201 * proceed without the key because we're going to create the dir_entry.
202 * @fname: the filename information to be filled in
203 * @fid: fid retrieved from user-provided filename
205 * This overlay function is necessary to properly encode @fname after
206 * encryption, as it will be sent over the wire.
207 * This overlay function is also necessary to handle the case of operations
208 * carried out without the key. Normally llcrypt makes use of digested names in
209 * that case. Having a digested name works for local file systems that can call
210 * llcrypt_match_name(), but Lustre server side is not aware of encryption.
211 * So for keyless @lookup operations on long names, for Lustre we choose to
212 * present to users the encoded struct ll_digest_filename, instead of a digested
213 * name. FID and name hash can then easily be extracted and put into the
214 * requests sent to servers.
216 int ll_setup_filename(struct inode *dir, const struct qstr *iname,
217 int lookup, struct llcrypt_name *fname,
224 if (fid && IS_ENCRYPTED(dir) && !llcrypt_has_encryption_key(dir) &&
225 iname->name[0] == '_')
228 dname.name = iname->name + digested;
229 dname.len = iname->len - digested;
236 rc = llcrypt_setup_filename(dir, &dname, lookup, fname);
237 if (rc == -ENOENT && lookup &&
238 ((is_root_inode(dir) && iname->len == strlen(dot_fscrypt_name) &&
239 strncmp(iname->name, dot_fscrypt_name, iname->len) == 0) ||
240 (!llcrypt_has_encryption_key(dir) &&
241 unlikely(filename_is_volatile(iname->name, iname->len, NULL))))) {
242 /* In case of subdir mount of an encrypted directory, we allow
243 * lookup of /.fscrypt directory.
245 /* For purpose of migration or mirroring without enc key, we
246 * allow lookup of volatile file without enc context.
248 memset(fname, 0, sizeof(struct llcrypt_name));
249 fname->disk_name.name = (unsigned char *)iname->name;
250 fname->disk_name.len = iname->len;
257 /* Without the key, for long names user should have struct
258 * ll_digest_filename representation of the dentry instead of
259 * the name. So make sure it is valid, return fid and put
260 * excerpt of cipher text name in disk_name.
262 struct ll_digest_filename *digest;
264 if (fname->crypto_buf.len < sizeof(struct ll_digest_filename)) {
268 digest = (struct ll_digest_filename *)fname->crypto_buf.name;
269 *fid = digest->ldf_fid;
270 if (!fid_is_sane(fid)) {
274 fname->disk_name.name = digest->ldf_excerpt;
275 fname->disk_name.len = LLCRYPT_FNAME_DIGEST_SIZE;
277 if (IS_ENCRYPTED(dir) &&
278 !name_is_dot_or_dotdot(fname->disk_name.name,
279 fname->disk_name.len)) {
280 int presented_len = critical_chars(fname->disk_name.name,
281 fname->disk_name.len);
284 buf = kmalloc(presented_len + 1, GFP_NOFS);
290 if (presented_len == fname->disk_name.len)
291 memcpy(buf, fname->disk_name.name, presented_len);
293 critical_encode(fname->disk_name.name,
294 fname->disk_name.len, buf);
295 buf[presented_len] = '\0';
296 kfree(fname->crypto_buf.name);
297 fname->crypto_buf.name = buf;
298 fname->crypto_buf.len = presented_len;
299 fname->disk_name.name = fname->crypto_buf.name;
300 fname->disk_name.len = fname->crypto_buf.len;
306 llcrypt_free_filename(fname);
311 * ll_fname_disk_to_usr() - overlay to llcrypt_fname_disk_to_usr
312 * @inode: the inode to convert name
313 * @hash: major hash for inode
314 * @minor_hash: minor hash for inode
315 * @iname: the user-provided filename needing conversion
316 * @oname: the filename information to be filled in
317 * @fid: the user-provided fid for filename
319 * The caller must have allocated sufficient memory for the @oname string.
321 * This overlay function is necessary to properly decode @iname before
322 * decryption, as it comes from the wire.
323 * This overlay function is also necessary to handle the case of operations
324 * carried out without the key. Normally llcrypt makes use of digested names in
325 * that case. Having a digested name works for local file systems that can call
326 * llcrypt_match_name(), but Lustre server side is not aware of encryption.
327 * So for keyless @lookup operations on long names, for Lustre we choose to
328 * present to users the encoded struct ll_digest_filename, instead of a digested
329 * name. FID and name hash can then easily be extracted and put into the
330 * requests sent to servers.
332 int ll_fname_disk_to_usr(struct inode *inode,
333 u32 hash, u32 minor_hash,
334 struct llcrypt_str *iname, struct llcrypt_str *oname,
337 struct llcrypt_str lltr = LLTR_INIT(iname->name, iname->len);
338 struct ll_digest_filename digest;
343 if (IS_ENCRYPTED(inode)) {
344 if (!name_is_dot_or_dotdot(lltr.name, lltr.len) &&
345 strnchr(lltr.name, lltr.len, '=')) {
346 /* Only proceed to critical decode if
347 * iname contains espace char '='.
351 buf = kmalloc(len, GFP_NOFS);
355 len = critical_decode(lltr.name, len, buf);
359 if (lltr.len > LLCRYPT_FNAME_MAX_UNDIGESTED_SIZE &&
360 !llcrypt_has_encryption_key(inode) &&
361 llcrypt_policy_has_filename_enc(inode)) {
363 /* Without the key for long names, set the dentry name
364 * to the representing struct ll_digest_filename. It
365 * will be encoded by llcrypt for display, and will
366 * enable further lookup requests.
370 digest.ldf_fid = *fid;
371 memcpy(digest.ldf_excerpt,
372 LLCRYPT_FNAME_DIGEST(lltr.name, lltr.len),
373 LLCRYPT_FNAME_DIGEST_SIZE);
375 lltr.name = (char *)&digest;
376 lltr.len = sizeof(digest);
378 oname->name[0] = '_';
379 oname->name = oname->name + 1;
384 rc = llcrypt_fname_disk_to_usr(inode, hash, minor_hash, &lltr, oname);
387 oname->name = oname->name - digested;
388 oname->len = oname->len + digested;
393 /* Copied from llcrypt_d_revalidate, as it is not exported */
395 * Validate dentries in encrypted directories to make sure we aren't potentially
396 * caching stale dentries after a key has been added.
398 int ll_revalidate_d_crypto(struct dentry *dentry, unsigned int flags)
405 * Plaintext names are always valid, since llcrypt doesn't support
406 * reverting to ciphertext names without evicting the directory's inode
407 * -- which implies eviction of the dentries in the directory.
409 if (!(dentry->d_flags & DCACHE_ENCRYPTED_NAME))
413 * Ciphertext name; valid if the directory's key is still unavailable.
415 * Although llcrypt forbids rename() on ciphertext names, we still must
416 * use dget_parent() here rather than use ->d_parent directly. That's
417 * because a corrupted fs image may contain directory hard links, which
418 * the VFS handles by moving the directory's dentry tree in the dcache
419 * each time ->lookup() finds the directory and it already has a dentry
420 * elsewhere. Thus ->d_parent can be changing, and we must safely grab
421 * a reference to some ->d_parent to prevent it from being freed.
424 if (flags & LOOKUP_RCU)
427 dir = dget_parent(dentry);
428 err = llcrypt_get_encryption_info(d_inode(dir));
429 valid = !llcrypt_has_encryption_key(d_inode(dir));
438 const struct llcrypt_operations lustre_cryptops = {
439 .key_prefix = "lustre:",
440 .get_context = ll_get_context,
441 .set_context = ll_set_context,
442 .dummy_context = ll_dummy_context,
443 .empty_dir = ll_empty_dir,
444 .max_namelen = NAME_MAX,
446 #else /* !HAVE_LUSTRE_CRYPTO */
447 int ll_set_encflags(struct inode *inode, void *encctx, __u32 encctxlen,
453 int ll_file_open_encrypt(struct inode *inode, struct file *filp)
455 return llcrypt_file_open(inode, filp);
458 void llcrypt_free_ctx(void *encctx, __u32 size)
462 bool ll_sbi_has_test_dummy_encryption(struct ll_sb_info *sbi)
467 bool ll_sbi_has_encrypt(struct ll_sb_info *sbi)
472 void ll_sbi_set_encrypt(struct ll_sb_info *sbi, bool set)
476 int ll_setup_filename(struct inode *dir, const struct qstr *iname,
477 int lookup, struct llcrypt_name *fname,
486 return llcrypt_setup_filename(dir, iname, lookup, fname);
489 int ll_fname_disk_to_usr(struct inode *inode,
490 u32 hash, u32 minor_hash,
491 struct llcrypt_str *iname, struct llcrypt_str *oname,
494 return llcrypt_fname_disk_to_usr(inode, hash, minor_hash, iname, oname);
497 int ll_revalidate_d_crypto(struct dentry *dentry, unsigned int flags)