1 // SPDX-License-Identifier: GPL-2.0
3  * Encryption policy functions for per-file encryption support.
23  * fscrypt_policies_equal() - check whether two encryption policies are the same
32 	if (policy1->version != policy2->version)  in fscrypt_policies_equal()
41 	switch (policy->version) {  in fscrypt_policy_to_key_spec()
43 		key_spec->type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR;  in fscrypt_policy_to_key_spec()
44 		memcpy(key_spec->u.descriptor, policy->v1.master_key_descriptor,  in fscrypt_policy_to_key_spec()
48 		key_spec->type = FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER;  in fscrypt_policy_to_key_spec()
49 		memcpy(key_spec->u.identifier, policy->v2.master_key_identifier,  in fscrypt_policy_to_key_spec()
54 		return -EINVAL;  in fscrypt_policy_to_key_spec()
60 	if (!sb->s_cop->get_dummy_policy)  in fscrypt_get_dummy_policy()
62 	return sb->s_cop->get_dummy_policy(sb);  in fscrypt_get_dummy_policy()
114 	if (mode->ivsize < offsetofend(union fscrypt_iv, nonce)) {  in supported_direct_key_modes()
116 			     mode->friendly_name);  in supported_direct_key_modes()
125 	const char *type = (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64)  in supported_iv_ino_lblk_policy()
127 	struct super_block *sb = inode->i_sb;  in supported_iv_ino_lblk_policy()
130 	 * IV_INO_LBLK_* exist only because of hardware limitations, and  in supported_iv_ino_lblk_policy()
131 	 * currently the only known use case for them involves AES-256-XTS.  in supported_iv_ino_lblk_policy()
133 	 * allow AES-256-XTS here.  This can be relaxed later if a use case for  in supported_iv_ino_lblk_policy()
136 	if (policy->contents_encryption_mode != FSCRYPT_MODE_AES_256_XTS) {  in supported_iv_ino_lblk_policy()
138 			     "Can't use %s policy with contents mode other than AES-256-XTS",  in supported_iv_ino_lblk_policy()
147 	if (!sb->s_cop->has_stable_inodes ||  in supported_iv_ino_lblk_policy()
148 	    !sb->s_cop->has_stable_inodes(sb)) {  in supported_iv_ino_lblk_policy()
151 			     type, sb->s_id);  in supported_iv_ino_lblk_policy()
162 	if (!sb->s_cop->has_32bit_inodes) {  in supported_iv_ino_lblk_policy()
165 			     type, sb->s_id);  in supported_iv_ino_lblk_policy()
177 			     type, sb->s_id);  in supported_iv_ino_lblk_policy()
186 	if (!fscrypt_valid_enc_modes_v1(policy->contents_encryption_mode,  in fscrypt_supported_v1_policy()
187 				     policy->filenames_encryption_mode)) {  in fscrypt_supported_v1_policy()
190 			     policy->contents_encryption_mode,  in fscrypt_supported_v1_policy()
191 			     policy->filenames_encryption_mode);  in fscrypt_supported_v1_policy()
195 	if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |  in fscrypt_supported_v1_policy()
198 			     policy->flags);  in fscrypt_supported_v1_policy()
202 	if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) &&  in fscrypt_supported_v1_policy()
203 	    !supported_direct_key_modes(inode, policy->contents_encryption_mode,  in fscrypt_supported_v1_policy()
204 					policy->filenames_encryption_mode))  in fscrypt_supported_v1_policy()
222 	if (!fscrypt_valid_enc_modes_v2(policy->contents_encryption_mode,  in fscrypt_supported_v2_policy()
223 				     policy->filenames_encryption_mode)) {  in fscrypt_supported_v2_policy()
226 			     policy->contents_encryption_mode,  in fscrypt_supported_v2_policy()
227 			     policy->filenames_encryption_mode);  in fscrypt_supported_v2_policy()
231 	if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK |  in fscrypt_supported_v2_policy()
236 			     policy->flags);  in fscrypt_supported_v2_policy()
240 	count += !!(policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY);  in fscrypt_supported_v2_policy()
241 	count += !!(policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64);  in fscrypt_supported_v2_policy()
242 	count += !!(policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32);  in fscrypt_supported_v2_policy()
245 			     policy->flags);  in fscrypt_supported_v2_policy()
249 	if (policy->log2_data_unit_size) {  in fscrypt_supported_v2_policy()
250 		if (!inode->i_sb->s_cop->supports_subblock_data_units) {  in fscrypt_supported_v2_policy()
255 		if (policy->log2_data_unit_size > inode->i_blkbits ||  in fscrypt_supported_v2_policy()
256 		    policy->log2_data_unit_size < SECTOR_SHIFT /* 9 */) {  in fscrypt_supported_v2_policy()
259 				     policy->log2_data_unit_size);  in fscrypt_supported_v2_policy()
262 		if (policy->log2_data_unit_size != inode->i_blkbits &&  in fscrypt_supported_v2_policy()
263 		    (policy->flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) {  in fscrypt_supported_v2_policy()
269 				     "Sub-block data units not yet supported with IV_INO_LBLK_32");  in fscrypt_supported_v2_policy()
274 	if ((policy->flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY) &&  in fscrypt_supported_v2_policy()
275 	    !supported_direct_key_modes(inode, policy->contents_encryption_mode,  in fscrypt_supported_v2_policy()
276 					policy->filenames_encryption_mode))  in fscrypt_supported_v2_policy()
279 	if ((policy->flags & (FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 |  in fscrypt_supported_v2_policy()
284 	if (memchr_inv(policy->__reserved, 0, sizeof(policy->__reserved))) {  in fscrypt_supported_v2_policy()
293  * fscrypt_supported_policy() - check whether an encryption policy is supported
307 	switch (policy_u->version) {  in fscrypt_supported_policy()
309 		return fscrypt_supported_v1_policy(&policy_u->v1, inode);  in fscrypt_supported_policy()
311 		return fscrypt_supported_v2_policy(&policy_u->v2, inode);  in fscrypt_supported_policy()
317  * fscrypt_new_context() - create a new fscrypt_context
333 	switch (policy_u->version) {  in fscrypt_new_context()
335 		const struct fscrypt_policy_v1 *policy = &policy_u->v1;  in fscrypt_new_context()
336 		struct fscrypt_context_v1 *ctx = &ctx_u->v1;  in fscrypt_new_context()
338 		ctx->version = FSCRYPT_CONTEXT_V1;  in fscrypt_new_context()
339 		ctx->contents_encryption_mode =  in fscrypt_new_context()
340 			policy->contents_encryption_mode;  in fscrypt_new_context()
341 		ctx->filenames_encryption_mode =  in fscrypt_new_context()
342 			policy->filenames_encryption_mode;  in fscrypt_new_context()
343 		ctx->flags = policy->flags;  in fscrypt_new_context()
344 		memcpy(ctx->master_key_descriptor,  in fscrypt_new_context()
345 		       policy->master_key_descriptor,  in fscrypt_new_context()
346 		       sizeof(ctx->master_key_descriptor));  in fscrypt_new_context()
347 		memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);  in fscrypt_new_context()
351 		const struct fscrypt_policy_v2 *policy = &policy_u->v2;  in fscrypt_new_context()
352 		struct fscrypt_context_v2 *ctx = &ctx_u->v2;  in fscrypt_new_context()
354 		ctx->version = FSCRYPT_CONTEXT_V2;  in fscrypt_new_context()
355 		ctx->contents_encryption_mode =  in fscrypt_new_context()
356 			policy->contents_encryption_mode;  in fscrypt_new_context()
357 		ctx->filenames_encryption_mode =  in fscrypt_new_context()
358 			policy->filenames_encryption_mode;  in fscrypt_new_context()
359 		ctx->flags = policy->flags;  in fscrypt_new_context()
360 		ctx->log2_data_unit_size = policy->log2_data_unit_size;  in fscrypt_new_context()
361 		memcpy(ctx->master_key_identifier,  in fscrypt_new_context()
362 		       policy->master_key_identifier,  in fscrypt_new_context()
363 		       sizeof(ctx->master_key_identifier));  in fscrypt_new_context()
364 		memcpy(ctx->nonce, nonce, FSCRYPT_FILE_NONCE_SIZE);  in fscrypt_new_context()
372  * fscrypt_policy_from_context() - convert an fscrypt_context to
380  * Return: 0 on success, or -EINVAL if the fscrypt_context has an unrecognized
393 		return -EINVAL;  in fscrypt_policy_from_context()
395 	switch (ctx_u->version) {  in fscrypt_policy_from_context()
397 		const struct fscrypt_context_v1 *ctx = &ctx_u->v1;  in fscrypt_policy_from_context()
398 		struct fscrypt_policy_v1 *policy = &policy_u->v1;  in fscrypt_policy_from_context()
400 		policy->version = FSCRYPT_POLICY_V1;  in fscrypt_policy_from_context()
401 		policy->contents_encryption_mode =  in fscrypt_policy_from_context()
402 			ctx->contents_encryption_mode;  in fscrypt_policy_from_context()
403 		policy->filenames_encryption_mode =  in fscrypt_policy_from_context()
404 			ctx->filenames_encryption_mode;  in fscrypt_policy_from_context()
405 		policy->flags = ctx->flags;  in fscrypt_policy_from_context()
406 		memcpy(policy->master_key_descriptor,  in fscrypt_policy_from_context()
407 		       ctx->master_key_descriptor,  in fscrypt_policy_from_context()
408 		       sizeof(policy->master_key_descriptor));  in fscrypt_policy_from_context()
412 		const struct fscrypt_context_v2 *ctx = &ctx_u->v2;  in fscrypt_policy_from_context()
413 		struct fscrypt_policy_v2 *policy = &policy_u->v2;  in fscrypt_policy_from_context()
415 		policy->version = FSCRYPT_POLICY_V2;  in fscrypt_policy_from_context()
416 		policy->contents_encryption_mode =  in fscrypt_policy_from_context()
417 			ctx->contents_encryption_mode;  in fscrypt_policy_from_context()
418 		policy->filenames_encryption_mode =  in fscrypt_policy_from_context()
419 			ctx->filenames_encryption_mode;  in fscrypt_policy_from_context()
420 		policy->flags = ctx->flags;  in fscrypt_policy_from_context()
421 		policy->log2_data_unit_size = ctx->log2_data_unit_size;  in fscrypt_policy_from_context()
422 		memcpy(policy->__reserved, ctx->__reserved,  in fscrypt_policy_from_context()
423 		       sizeof(policy->__reserved));  in fscrypt_policy_from_context()
424 		memcpy(policy->master_key_identifier,  in fscrypt_policy_from_context()
425 		       ctx->master_key_identifier,  in fscrypt_policy_from_context()
426 		       sizeof(policy->master_key_identifier));  in fscrypt_policy_from_context()
431 	return -EINVAL;  in fscrypt_policy_from_context()
444 		*policy = ci->ci_policy;  in fscrypt_get_policy()
449 		return -ENODATA;  in fscrypt_get_policy()
451 	ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));  in fscrypt_get_policy()
453 		return (ret == -ERANGE) ? -EINVAL : ret;  in fscrypt_get_policy()
467 		return -EINVAL;  in set_encryption_policy()
469 	switch (policy->version) {  in set_encryption_policy()
475 		 * same encrypted files (even just read-only access).  The new  in set_encryption_policy()
477 		 * an improved key derivation function and allows non-root users  in set_encryption_policy()
483 			     current->comm, current->pid);  in set_encryption_policy()
486 		err = fscrypt_verify_key_added(inode->i_sb,  in set_encryption_policy()
487 					       policy->v2.master_key_identifier);  in set_encryption_policy()
490 		if (policy->v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)  in set_encryption_policy()
491 …LBLK_32 encryption policy.  This should only be used if there are certain hardware limitations.\n",  in set_encryption_policy()
492 				     current->comm, current->pid);  in set_encryption_policy()
496 		return -EINVAL;  in set_encryption_policy()
502 	return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, NULL);  in set_encryption_policy()
515 		return -EFAULT;  in fscrypt_ioctl_set_policy()
519 		return -EINVAL;  in fscrypt_ioctl_set_policy()
522 	 * We should just copy the remaining 'size - 1' bytes here, but a  in fscrypt_ioctl_set_policy()
525 	 * it's a compile-time constant.  Thus it would think copy_from_user()  in fscrypt_ioctl_set_policy()
526 	 * is passed compile-time constant ULONG_MAX, causing the compile-time  in fscrypt_ioctl_set_policy()
528 	 * when building an i386 kernel with -Os and branch profiling enabled.  in fscrypt_ioctl_set_policy()
534 		return -EFAULT;  in fscrypt_ioctl_set_policy()
538 		return -EACCES;  in fscrypt_ioctl_set_policy()
547 	if (ret == -ENODATA) {  in fscrypt_ioctl_set_policy()
548 		if (!S_ISDIR(inode->i_mode))  in fscrypt_ioctl_set_policy()
549 			ret = -ENOTDIR;  in fscrypt_ioctl_set_policy()
551 			ret = -ENOENT;  in fscrypt_ioctl_set_policy()
552 		else if (!inode->i_sb->s_cop->empty_dir(inode))  in fscrypt_ioctl_set_policy()
553 			ret = -ENOTEMPTY;  in fscrypt_ioctl_set_policy()
556 	} else if (ret == -EINVAL ||  in fscrypt_ioctl_set_policy()
560 		ret = -EEXIST;  in fscrypt_ioctl_set_policy()
581 		return -EINVAL;  in fscrypt_ioctl_get_policy()
584 		return -EFAULT;  in fscrypt_ioctl_get_policy()
609 		return -EFAULT;  in fscrypt_ioctl_get_policy_ex()
612 		return -EOVERFLOW;  in fscrypt_ioctl_get_policy_ex()
616 		return -EFAULT;  in fscrypt_ioctl_get_policy_ex()
628 	ret = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));  in fscrypt_ioctl_get_nonce()
632 		return -EINVAL;  in fscrypt_ioctl_get_nonce()
635 		return -EFAULT;  in fscrypt_ioctl_get_nonce()
641  * fscrypt_has_permitted_context() - is a file's encryption policy permitted
649  * ->lookup() to succeed, or for a regular file before allowing it to be opened)
653  * same encryption policy.  The pre-access check is needed to detect potentially
665 	if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) &&  in fscrypt_has_permitted_context()
666 	    !S_ISLNK(child->i_mode))  in fscrypt_has_permitted_context()
684 	 * Performance-wise this is not a big deal because we already don't  in fscrypt_has_permitted_context()
707 	if (err1 == -EINVAL && err2 == -EINVAL)  in fscrypt_has_permitted_context()
730 		return &fscrypt_get_inode_info_raw(dir)->ci_policy;  in fscrypt_policy_to_inherit()
733 	return fscrypt_get_dummy_policy(dir->i_sb);  in fscrypt_policy_to_inherit()
737  * fscrypt_context_for_new_inode() - create an encryption context for a new inode
741  * Given an in-core "prepared" (via fscrypt_prepare_new_inode) inode,
756 		return -ENOKEY;  in fscrypt_context_for_new_inode()
758 	return fscrypt_new_context(ctx, &ci->ci_policy, ci->ci_nonce);  in fscrypt_context_for_new_inode()
763  * fscrypt_set_context() - Set the fscrypt context of a new inode
765  * @fs_data: private data given by FS and passed to ->set_context()
768  * filesystem transaction.  Everything here must be %GFP_NOFS-safe.
770  * Return: 0 on success, -errno on failure
787 	if (ci->ci_policy.version == FSCRYPT_POLICY_V2 &&  in fscrypt_set_context()
788 	    (ci->ci_policy.v2.flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32))  in fscrypt_set_context()
789 		fscrypt_hash_inode_number(ci, ci->ci_master_key);  in fscrypt_set_context()
791 	return inode->i_sb->s_cop->set_context(inode, &ctx, ctxsize, fs_data);  in fscrypt_set_context()
796  * fscrypt_parse_test_dummy_encryption() - parse the test_dummy_encryption mount option
799  *	result from parsing the option.  Zero-initialize this.  If a policy is
803  * Return: 0 on success; -EINVAL if the argument is invalid; -EEXIST if the
804  *	   argument conflicts with one already specified; or -ENOMEM.
813 	if (param->type == fs_value_is_string && *param->string)  in fscrypt_parse_test_dummy_encryption()
814 		arg = param->string;  in fscrypt_parse_test_dummy_encryption()
818 		return -ENOMEM;  in fscrypt_parse_test_dummy_encryption()
821 		policy->version = FSCRYPT_POLICY_V1;  in fscrypt_parse_test_dummy_encryption()
822 		policy->v1.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;  in fscrypt_parse_test_dummy_encryption()
823 		policy->v1.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;  in fscrypt_parse_test_dummy_encryption()
824 		memset(policy->v1.master_key_descriptor, 0x42,  in fscrypt_parse_test_dummy_encryption()
827 		policy->version = FSCRYPT_POLICY_V2;  in fscrypt_parse_test_dummy_encryption()
828 		policy->v2.contents_encryption_mode = FSCRYPT_MODE_AES_256_XTS;  in fscrypt_parse_test_dummy_encryption()
829 		policy->v2.filenames_encryption_mode = FSCRYPT_MODE_AES_256_CTS;  in fscrypt_parse_test_dummy_encryption()
831 				policy->v2.master_key_identifier);  in fscrypt_parse_test_dummy_encryption()
833 		err = -EINVAL;  in fscrypt_parse_test_dummy_encryption()
837 	if (dummy_policy->policy) {  in fscrypt_parse_test_dummy_encryption()
838 		if (fscrypt_policies_equal(policy, dummy_policy->policy))  in fscrypt_parse_test_dummy_encryption()
841 			err = -EEXIST;  in fscrypt_parse_test_dummy_encryption()
844 	dummy_policy->policy = policy;  in fscrypt_parse_test_dummy_encryption()
854  * fscrypt_dummy_policies_equal() - check whether two dummy policies are equal
863 	if (!p1->policy && !p2->policy)  in fscrypt_dummy_policies_equal()
865 	if (!p1->policy || !p2->policy)  in fscrypt_dummy_policies_equal()
867 	return fscrypt_policies_equal(p1->policy, p2->policy);  in fscrypt_dummy_policies_equal()
872  * fscrypt_show_test_dummy_encryption() - show '-o test_dummy_encryption'
889 	vers = policy->version;  in fscrypt_show_test_dummy_encryption()