1 // SPDX-License-Identifier: GPL-2.0
3 * Encryption policy functions for per-file encryption support.
5 * Copyright (C) 2015, Google, Inc.
6 * Copyright (C) 2015, Motorola Mobility.
8 * Originally written by Michael Halcrow, 2015.
9 * Modified by Jaegeuk Kim, 2015.
10 * Modified by Eric Biggers, 2019 for v2 policy support.
13 #include <linux/fs_context.h>
14 #include <linux/random.h>
15 #include <linux/seq_file.h>
16 #include <linux/string.h>
17 #include <linux/mount.h>
18 #include "fscrypt_private.h"
21 * fscrypt_policies_equal() - check whether two encryption policies are the same
22 * @policy1: the first policy
23 * @policy2: the second policy
25 * Return: %true if equal, else %false
27 bool fscrypt_policies_equal(const union fscrypt_policy *policy1,
28 const union fscrypt_policy *policy2)
30 if (policy1->version != policy2->version)
33 return !memcmp(policy1, policy2, fscrypt_policy_size(policy1));
36 int fscrypt_policy_to_key_spec(const union fscrypt_policy *policy,
37 struct fscrypt_key_specifier *key_spec)
39 switch (policy->version) {
40 case FSCRYPT_POLICY_V1:
41 key_spec->type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;
42 memcpy(key_spec->u.descriptor, policy->v1.master_key_descriptor,
43 FSCRYPT_KEY_DESCRIPTOR_SIZE);
45 case FSCRYPT_POLICY_V2:
46 key_spec->type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;
47 memcpy(key_spec->u.identifier, policy->v2.master_key_identifier,
48 FSCRYPT_KEY_IDENTIFIER_SIZE);
56 static const union fscrypt_policy *
57 fscrypt_get_dummy_policy(struct super_block *sb)
59 if (!sb->s_cop->get_dummy_policy)
61 return sb->s_cop->get_dummy_policy(sb);
64 static bool fscrypt_valid_enc_modes(u32 contents_mode, u32 filenames_mode)
66 if (contents_mode == FSCRYPT_MODE_AES_256_XTS &&
67 filenames_mode == FSCRYPT_MODE_AES_256_CTS)
70 if (contents_mode == FSCRYPT_MODE_AES_128_CBC &&
71 filenames_mode == FSCRYPT_MODE_AES_128_CTS)
74 if (contents_mode == FSCRYPT_MODE_ADIANTUM &&
75 filenames_mode == FSCRYPT_MODE_ADIANTUM)
81 static bool supported_direct_key_modes(const struct inode *inode,
82 u32 contents_mode, u32 filenames_mode)
84 const struct fscrypt_mode *mode;
86 if (contents_mode != filenames_mode) {
88 "Direct key flag not allowed with different contents and filenames modes");
91 mode = &fscrypt_modes[contents_mode];
93 if (mode->ivsize < offsetofend(union fscrypt_iv, nonce)) {
94 fscrypt_warn(inode, "Direct key flag not allowed with %s",
101 static bool supported_iv_ino_lblk_policy(const struct fscrypt_policy_v2 *policy,
102 const struct inode *inode,
104 int max_ino_bits, int max_lblk_bits)
106 struct super_block *sb = inode->i_sb;
107 int ino_bits = 64, lblk_bits = 64;
110 * IV_INO_LBLK_* exist only because of hardware limitations, and
111 * currently the only known use case for them involves AES-256-XTS.
112 * That's also all we test currently. For these reasons, for now only
113 * allow AES-256-XTS here. This can be relaxed later if a use case for
114 * IV_INO_LBLK_* with other encryption modes arises.
116 if (policy->contents_encryption_mode != FSCRYPT_MODE_AES_256_XTS) {
118 "Can't use %s policy with contents mode other than AES-256-XTS",
124 * It's unsafe to include inode numbers in the IVs if the filesystem can
125 * potentially renumber inodes, e.g. via filesystem shrinking.
127 if (!sb->s_cop->has_stable_inodes ||
128 !sb->s_cop->has_stable_inodes(sb)) {
130 "Can't use %s policy on filesystem '%s' because it doesn't have stable inode numbers",
134 if (sb->s_cop->get_ino_and_lblk_bits)
135 sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);
136 if (ino_bits > max_ino_bits) {
138 "Can't use %s policy on filesystem '%s' because its inode numbers are too long",
142 if (lblk_bits > max_lblk_bits) {
144 "Can't use %s policy on filesystem '%s' because its block numbers are too long",
151 static bool fscrypt_supported_v1_policy(const struct fscrypt_policy_v1 *policy,
152 const struct inode *inode)
154 if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
155 policy->filenames_encryption_mode)) {
157 "Unsupported encryption modes (contents %d, filenames %d)",
158 policy->contents_encryption_mode,
159 policy->filenames_encryption_mode);
163 if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
164 FSCRYPT_POLICY_FLAG_DIRECT_KEY)) {
165 fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)",
170 if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) &&
171 !supported_direct_key_modes(inode, policy->contents_encryption_mode,
172 policy->filenames_encryption_mode))
175 if (IS_CASEFOLDED(inode)) {
176 /* With v1, there's no way to derive dirhash keys. */
178 "v1 policies can't be used on casefolded directories");
185 static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy,
186 const struct inode *inode)
190 if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
191 policy->filenames_encryption_mode)) {
193 "Unsupported encryption modes (contents %d, filenames %d)",
194 policy->contents_encryption_mode,
195 policy->filenames_encryption_mode);
199 if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |
200 FSCRYPT_POLICY_FLAG_DIRECT_KEY |
201 FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |
202 FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
203 fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)",
208 count += !!(policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY);
209 count += !!(policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64);
210 count += !!(policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32);
212 fscrypt_warn(inode, "Mutually exclusive encryption flags (0x%02x)",
217 if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) &&
218 !supported_direct_key_modes(inode, policy->contents_encryption_mode,
219 policy->filenames_encryption_mode))
222 if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64) &&
223 !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_64",
228 * IV_INO_LBLK_32 hashes the inode number, so in principle it can
229 * support any ino_bits. However, currently the inode number is gotten
230 * from inode::i_ino which is 'unsigned long'. So for now the
231 * implementation limit is 32 bits.
233 if ((policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32) &&
234 !supported_iv_ino_lblk_policy(policy, inode, "IV_INO_LBLK_32",
238 if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) {
239 fscrypt_warn(inode, "Reserved bits set in encryption policy");
247 * fscrypt_supported_policy() - check whether an encryption policy is supported
248 * @policy_u: the encryption policy
249 * @inode: the inode on which the policy will be used
251 * Given an encryption policy, check whether all its encryption modes and other
252 * settings are supported by this kernel on the given inode. (But we don't
253 * currently don't check for crypto API support here, so attempting to use an
254 * algorithm not configured into the crypto API will still fail later.)
256 * Return: %true if supported, else %false
258 bool fscrypt_supported_policy(const union fscrypt_policy *policy_u,
259 const struct inode *inode)
261 switch (policy_u->version) {
262 case FSCRYPT_POLICY_V1:
263 return fscrypt_supported_v1_policy(&policy_u->v1, inode);
264 case FSCRYPT_POLICY_V2:
265 return fscrypt_supported_v2_policy(&policy_u->v2, inode);
271 * fscrypt_new_context() - create a new fscrypt_context
272 * @ctx_u: output context
273 * @policy_u: input policy
274 * @nonce: nonce to use
276 * Create an fscrypt_context for an inode that is being assigned the given
277 * encryption policy. @nonce must be a new random nonce.
279 * Return: the size of the new context in bytes.
281 static int fscrypt_new_context(union fscrypt_context *ctx_u,
282 const union fscrypt_policy *policy_u,
283 const u8 nonce[FSCRYPT_FILE_NONCE_SIZE])
285 memset(ctx_u, 0, sizeof(*ctx_u));
287 switch (policy_u->version) {
288 case FSCRYPT_POLICY_V1: {
289 const struct fscrypt_policy_v1 *policy = &policy_u->v1;
290 struct fscrypt_context_v1 *ctx = &ctx_u->v1;
292 ctx->version = FSCRYPT_CONTEXT_V1;
293 ctx->contents_encryption_mode =
294 policy->contents_encryption_mode;
295 ctx->filenames_encryption_mode =
296 policy->filenames_encryption_mode;
297 ctx->flags = policy->flags;
298 memcpy(ctx->master_key_descriptor,
299 policy->master_key_descriptor,
300 sizeof(ctx->master_key_descriptor));
301 memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);
304 case FSCRYPT_POLICY_V2: {
305 const struct fscrypt_policy_v2 *policy = &policy_u->v2;
306 struct fscrypt_context_v2 *ctx = &ctx_u->v2;
308 ctx->version = FSCRYPT_CONTEXT_V2;
309 ctx->contents_encryption_mode =
310 policy->contents_encryption_mode;
311 ctx->filenames_encryption_mode =
312 policy->filenames_encryption_mode;
313 ctx->flags = policy->flags;
314 memcpy(ctx->master_key_identifier,
315 policy->master_key_identifier,
316 sizeof(ctx->master_key_identifier));
317 memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);
325 * fscrypt_policy_from_context() - convert an fscrypt_context to
327 * @policy_u: output policy
328 * @ctx_u: input context
329 * @ctx_size: size of input context in bytes
331 * Given an fscrypt_context, build the corresponding fscrypt_policy.
333 * Return: 0 on success, or -EINVAL if the fscrypt_context has an unrecognized
334 * version number or size.
336 * This does *not* validate the settings within the policy itself, e.g. the
337 * modes, flags, and reserved bits. Use fscrypt_supported_policy() for that.
339 int fscrypt_policy_from_context(union fscrypt_policy *policy_u,
340 const union fscrypt_context *ctx_u,
343 memset(policy_u, 0, sizeof(*policy_u));
345 if (!fscrypt_context_is_valid(ctx_u, ctx_size))
348 switch (ctx_u->version) {
349 case FSCRYPT_CONTEXT_V1: {
350 const struct fscrypt_context_v1 *ctx = &ctx_u->v1;
351 struct fscrypt_policy_v1 *policy = &policy_u->v1;
353 policy->version = FSCRYPT_POLICY_V1;
354 policy->contents_encryption_mode =
355 ctx->contents_encryption_mode;
356 policy->filenames_encryption_mode =
357 ctx->filenames_encryption_mode;
358 policy->flags = ctx->flags;
359 memcpy(policy->master_key_descriptor,
360 ctx->master_key_descriptor,
361 sizeof(policy->master_key_descriptor));
364 case FSCRYPT_CONTEXT_V2: {
365 const struct fscrypt_context_v2 *ctx = &ctx_u->v2;
366 struct fscrypt_policy_v2 *policy = &policy_u->v2;
368 policy->version = FSCRYPT_POLICY_V2;
369 policy->contents_encryption_mode =
370 ctx->contents_encryption_mode;
371 policy->filenames_encryption_mode =
372 ctx->filenames_encryption_mode;
373 policy->flags = ctx->flags;
374 memcpy(policy->__reserved, ctx->__reserved,
375 sizeof(policy->__reserved));
376 memcpy(policy->master_key_identifier,
377 ctx->master_key_identifier,
378 sizeof(policy->master_key_identifier));
386 /* Retrieve an inode's encryption policy */
387 static int fscrypt_get_policy(struct inode *inode, union fscrypt_policy *policy)
389 const struct fscrypt_info *ci;
390 union fscrypt_context ctx;
393 ci = fscrypt_get_info(inode);
395 /* key available, use the cached policy */
396 *policy = ci->ci_policy;
400 if (!IS_ENCRYPTED(inode))
403 ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
405 return (ret == -ERANGE) ? -EINVAL : ret;
407 return fscrypt_policy_from_context(policy, &ctx, ret);
410 static int set_encryption_policy(struct inode *inode,
411 const union fscrypt_policy *policy)
413 u8 nonce[FSCRYPT_FILE_NONCE_SIZE];
414 union fscrypt_context ctx;
418 if (!fscrypt_supported_policy(policy, inode))
421 switch (policy->version) {
422 case FSCRYPT_POLICY_V1:
424 * The original encryption policy version provided no way of
425 * verifying that the correct master key was supplied, which was
426 * insecure in scenarios where multiple users have access to the
427 * same encrypted files (even just read-only access). The new
428 * encryption policy version fixes this and also implies use of
429 * an improved key derivation function and allows non-root users
430 * to securely remove keys. So as long as compatibility with
431 * old kernels isn't required, it is recommended to use the new
432 * policy version for all new encrypted directories.
434 pr_warn_once("%s (pid %d) is setting deprecated v1 encryption policy; recommend upgrading to v2.\n",
435 current->comm, current->pid);
437 case FSCRYPT_POLICY_V2:
438 err = fscrypt_verify_key_added(inode->i_sb,
439 policy->v2.master_key_identifier);
442 if (policy->v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)
443 pr_warn_once("%s (pid %d) is setting an IV_INO_LBLK_32 encryption policy. This should only be used if there are certain hardware limitations.\n",
444 current->comm, current->pid);
451 get_random_bytes(nonce, FSCRYPT_FILE_NONCE_SIZE);
452 ctxsize = fscrypt_new_context(&ctx, policy, nonce);
454 return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, NULL);
457 int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg)
459 union fscrypt_policy policy;
460 union fscrypt_policy existing_policy;
461 struct inode *inode = file_inode(filp);
466 if (get_user(policy.version, (const u8 __user *)arg))
469 size = fscrypt_policy_size(&policy);
474 * We should just copy the remaining 'size - 1' bytes here, but a
475 * bizarre bug in gcc 7 and earlier (fixed by gcc r255731) causes gcc to
476 * think that size can be 0 here (despite the check above!) *and* that
477 * it's a compile-time constant. Thus it would think copy_from_user()
478 * is passed compile-time constant ULONG_MAX, causing the compile-time
479 * buffer overflow check to fail, breaking the build. This only occurred
480 * when building an i386 kernel with -Os and branch profiling enabled.
482 * Work around it by just copying the first byte again...
484 version = policy.version;
485 if (copy_from_user(&policy, arg, size))
487 policy.version = version;
489 if (!inode_owner_or_capable(&init_user_ns, inode))
492 ret = mnt_want_write_file(filp);
498 ret = fscrypt_get_policy(inode, &existing_policy);
499 if (ret == -ENODATA) {
500 if (!S_ISDIR(inode->i_mode))
502 else if (IS_DEADDIR(inode))
504 else if (!inode->i_sb->s_cop->empty_dir(inode))
507 ret = set_encryption_policy(inode, &policy);
508 } else if (ret == -EINVAL ||
509 (ret == 0 && !fscrypt_policies_equal(&policy,
510 &existing_policy))) {
511 /* The file already uses a different encryption policy. */
517 mnt_drop_write_file(filp);
520 EXPORT_SYMBOL(fscrypt_ioctl_set_policy);
522 /* Original ioctl version; can only get the original policy version */
523 int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
525 union fscrypt_policy policy;
528 err = fscrypt_get_policy(file_inode(filp), &policy);
532 if (policy.version != FSCRYPT_POLICY_V1)
535 if (copy_to_user(arg, &policy, sizeof(policy.v1)))
539 EXPORT_SYMBOL(fscrypt_ioctl_get_policy);
541 /* Extended ioctl version; can get policies of any version */
542 int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *uarg)
544 struct fscrypt_get_policy_ex_arg arg;
545 union fscrypt_policy *policy = (union fscrypt_policy *)&arg.policy;
549 /* arg is policy_size, then policy */
550 BUILD_BUG_ON(offsetof(typeof(arg), policy_size) != 0);
551 BUILD_BUG_ON(offsetofend(typeof(arg), policy_size) !=
552 offsetof(typeof(arg), policy));
553 BUILD_BUG_ON(sizeof(arg.policy) != sizeof(*policy));
555 err = fscrypt_get_policy(file_inode(filp), policy);
558 policy_size = fscrypt_policy_size(policy);
560 if (copy_from_user(&arg, uarg, sizeof(arg.policy_size)))
563 if (policy_size > arg.policy_size)
565 arg.policy_size = policy_size;
567 if (copy_to_user(uarg, &arg, sizeof(arg.policy_size) + policy_size))
571 EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_policy_ex);
573 /* FS_IOC_GET_ENCRYPTION_NONCE: retrieve file's encryption nonce for testing */
574 int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg)
576 struct inode *inode = file_inode(filp);
577 union fscrypt_context ctx;
580 ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
583 if (!fscrypt_context_is_valid(&ctx, ret))
585 if (copy_to_user(arg, fscrypt_context_nonce(&ctx),
586 FSCRYPT_FILE_NONCE_SIZE))
590 EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_nonce);
593 * fscrypt_has_permitted_context() - is a file's encryption policy permitted
594 * within its directory?
596 * @parent: inode for parent directory
597 * @child: inode for file being looked up, opened, or linked into @parent
599 * Filesystems must call this before permitting access to an inode in a
600 * situation where the parent directory is encrypted (either before allowing
601 * ->lookup() to succeed, or for a regular file before allowing it to be opened)
602 * and before any operation that involves linking an inode into an encrypted
603 * directory, including link, rename, and cross rename. It enforces the
604 * constraint that within a given encrypted directory tree, all files use the
605 * same encryption policy. The pre-access check is needed to detect potentially
606 * malicious offline violations of this constraint, while the link and rename
607 * checks are needed to prevent online violations of this constraint.
609 * Return: 1 if permitted, 0 if forbidden.
611 int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
613 union fscrypt_policy parent_policy, child_policy;
616 /* No restrictions on file types which are never encrypted */
617 if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&
618 !S_ISLNK(child->i_mode))
621 /* No restrictions if the parent directory is unencrypted */
622 if (!IS_ENCRYPTED(parent))
625 /* Encrypted directories must not contain unencrypted files */
626 if (!IS_ENCRYPTED(child))
630 * Both parent and child are encrypted, so verify they use the same
631 * encryption policy. Compare the fscrypt_info structs if the keys are
632 * available, otherwise retrieve and compare the fscrypt_contexts.
634 * Note that the fscrypt_context retrieval will be required frequently
635 * when accessing an encrypted directory tree without the key.
636 * Performance-wise this is not a big deal because we already don't
637 * really optimize for file access without the key (to the extent that
638 * such access is even possible), given that any attempted access
639 * already causes a fscrypt_context retrieval and keyring search.
641 * In any case, if an unexpected error occurs, fall back to "forbidden".
644 err = fscrypt_get_encryption_info(parent, true);
647 err = fscrypt_get_encryption_info(child, true);
651 err1 = fscrypt_get_policy(parent, &parent_policy);
652 err2 = fscrypt_get_policy(child, &child_policy);
655 * Allow the case where the parent and child both have an unrecognized
656 * encryption policy, so that files with an unrecognized encryption
657 * policy can be deleted.
659 if (err1 == -EINVAL && err2 == -EINVAL)
665 return fscrypt_policies_equal(&parent_policy, &child_policy);
667 EXPORT_SYMBOL(fscrypt_has_permitted_context);
670 * Return the encryption policy that new files in the directory will inherit, or
671 * NULL if none, or an ERR_PTR() on error. If the directory is encrypted, also
672 * ensure that its key is set up, so that the new filename can be encrypted.
674 const union fscrypt_policy *fscrypt_policy_to_inherit(struct inode *dir)
678 if (IS_ENCRYPTED(dir)) {
679 err = fscrypt_require_key(dir);
682 return &dir->i_crypt_info->ci_policy;
685 return fscrypt_get_dummy_policy(dir->i_sb);
689 * fscrypt_set_context() - Set the fscrypt context of a new inode
690 * @inode: a new inode
691 * @fs_data: private data given by FS and passed to ->set_context()
693 * This should be called after fscrypt_prepare_new_inode(), generally during a
694 * filesystem transaction. Everything here must be %GFP_NOFS-safe.
696 * Return: 0 on success, -errno on failure
698 int fscrypt_set_context(struct inode *inode, void *fs_data)
700 struct fscrypt_info *ci = inode->i_crypt_info;
701 union fscrypt_context ctx;
704 /* fscrypt_prepare_new_inode() should have set up the key already. */
705 if (WARN_ON_ONCE(!ci))
708 BUILD_BUG_ON(sizeof(ctx) != FSCRYPT_SET_CONTEXT_MAX_SIZE);
709 ctxsize = fscrypt_new_context(&ctx, &ci->ci_policy, ci->ci_nonce);
712 * This may be the first time the inode number is available, so do any
713 * delayed key setup that requires the inode number.
715 if (ci->ci_policy.version == FSCRYPT_POLICY_V2 &&
716 (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {
717 const struct fscrypt_master_key *mk =
718 ci->ci_master_key->payload.data[0];
720 fscrypt_hash_inode_number(ci, mk);
723 return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, fs_data);
725 EXPORT_SYMBOL_GPL(fscrypt_set_context);
728 * fscrypt_parse_test_dummy_encryption() - parse the test_dummy_encryption mount option
729 * @param: the mount option
730 * @dummy_policy: (input/output) the place to write the dummy policy that will
731 * result from parsing the option. Zero-initialize this. If a policy is
732 * already set here (due to test_dummy_encryption being given multiple
733 * times), then this function will verify that the policies are the same.
735 * Return: 0 on success; -EINVAL if the argument is invalid; -EEXIST if the
736 * argument conflicts with one already specified; or -ENOMEM.
738 int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param,
739 struct fscrypt_dummy_policy *dummy_policy)
741 const char *arg = "v2";
742 union fscrypt_policy *policy;
745 if (param->type == fs_value_is_string && *param->string)
748 policy = kzalloc(sizeof(*policy), GFP_KERNEL);
752 if (!strcmp(arg, "v1")) {
753 policy->version = FSCRYPT_POLICY_V1;
754 policy->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
755 policy->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
756 memset(policy->v1.master_key_descriptor, 0x42,
757 FSCRYPT_KEY_DESCRIPTOR_SIZE);
758 } else if (!strcmp(arg, "v2")) {
759 policy->version = FSCRYPT_POLICY_V2;
760 policy->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;
761 policy->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;
762 err = fscrypt_get_test_dummy_key_identifier(
763 policy->v2.master_key_identifier);
771 if (dummy_policy->policy) {
772 if (fscrypt_policies_equal(policy, dummy_policy->policy))
778 dummy_policy->policy = policy;
785 EXPORT_SYMBOL_GPL(fscrypt_parse_test_dummy_encryption);
788 * fscrypt_dummy_policies_equal() - check whether two dummy policies are equal
789 * @p1: the first test dummy policy (may be unset)
790 * @p2: the second test dummy policy (may be unset)
792 * Return: %true if the dummy policies are both set and equal, or both unset.
794 bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1,
795 const struct fscrypt_dummy_policy *p2)
797 if (!p1->policy && !p2->policy)
799 if (!p1->policy || !p2->policy)
801 return fscrypt_policies_equal(p1->policy, p2->policy);
803 EXPORT_SYMBOL_GPL(fscrypt_dummy_policies_equal);
805 /* Deprecated, do not use */
806 int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg,
807 struct fscrypt_dummy_policy *dummy_policy)
809 struct fs_parameter param = {
810 .type = fs_value_is_string,
811 .string = arg ? (char *)arg : "",
813 return fscrypt_parse_test_dummy_encryption(¶m, dummy_policy) ?:
814 fscrypt_add_test_dummy_key(sb, dummy_policy);
816 EXPORT_SYMBOL_GPL(fscrypt_set_test_dummy_encryption);
819 * fscrypt_show_test_dummy_encryption() - show '-o test_dummy_encryption'
820 * @seq: the seq_file to print the option to
821 * @sep: the separator character to use
822 * @sb: the filesystem whose options are being shown
824 * Show the test_dummy_encryption mount option, if it was specified.
825 * This is mainly used for /proc/mounts.
827 void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep,
828 struct super_block *sb)
830 const union fscrypt_policy *policy = fscrypt_get_dummy_policy(sb);
836 vers = policy->version;
837 if (vers == FSCRYPT_POLICY_V1) /* Handle numbering quirk */
840 seq_printf(seq, "%ctest_dummy_encryption=v%d", sep, vers);
842 EXPORT_SYMBOL_GPL(fscrypt_show_test_dummy_encryption);