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/* SPDX-License-Identifier: GPL-2.0 */ /* * fscrypt.h: declarations for per-file encryption * * Filesystems that implement per-file encryption must include this header * file. * * Copyright (C) 2015, Google, Inc. * * Written by Michael Halcrow, 2015. * Modified by Jaegeuk Kim, 2015. */ #ifndef _LINUX_FSCRYPT_H #define _LINUX_FSCRYPT_H #include <linux/fs.h> #include <linux/mm.h> #include <linux/slab.h> #include <uapi/linux/fscrypt.h> /* * The lengths of all file contents blocks must be divisible by this value. * This is needed to ensure that all contents encryption modes will work, as * some of the supported modes don't support arbitrarily byte-aligned messages. * * Since the needed alignment is 16 bytes, most filesystems will meet this * requirement naturally, as typical block sizes are powers of 2. However, if a * filesystem can generate arbitrarily byte-aligned block lengths (e.g., via * compression), then it will need to pad to this alignment before encryption. */ #define FSCRYPT_CONTENTS_ALIGNMENT 16 union fscrypt_policy; struct fscrypt_inode_info; struct fs_parameter; struct seq_file; struct fscrypt_str { unsigned char *name; u32 len; }; struct fscrypt_name { const struct qstr *usr_fname; struct fscrypt_str disk_name; u32 hash; u32 minor_hash; struct fscrypt_str crypto_buf; bool is_nokey_name; }; #define FSTR_INIT(n, l) { .name = n, .len = l } #define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len) #define fname_name(p) ((p)->disk_name.name) #define fname_len(p) ((p)->disk_name.len) /* Maximum value for the third parameter of fscrypt_operations.set_context(). */ #define FSCRYPT_SET_CONTEXT_MAX_SIZE 40 #ifdef CONFIG_FS_ENCRYPTION /* Crypto operations for filesystems */ struct fscrypt_operations { /* * If set, then fs/crypto/ will allocate a global bounce page pool the * first time an encryption key is set up for a file. The bounce page * pool is required by the following functions: * * - fscrypt_encrypt_pagecache_blocks() * - fscrypt_zeroout_range() for files not using inline crypto * * If the filesystem doesn't use those, it doesn't need to set this. */ unsigned int needs_bounce_pages : 1; /* * If set, then fs/crypto/ will allow the use of encryption settings * that assume inode numbers fit in 32 bits (i.e. * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64}), provided that the other * prerequisites for these settings are also met. This is only useful * if the filesystem wants to support inline encryption hardware that is * limited to 32-bit or 64-bit data unit numbers and where programming * keyslots is very slow. */ unsigned int has_32bit_inodes : 1; /* * If set, then fs/crypto/ will allow users to select a crypto data unit * size that is less than the filesystem block size. This is done via * the log2_data_unit_size field of the fscrypt policy. This flag is * not compatible with filesystems that encrypt variable-length blocks * (i.e. blocks that aren't all equal to filesystem's block size), for * example as a result of compression. It's also not compatible with * the fscrypt_encrypt_block_inplace() and * fscrypt_decrypt_block_inplace() functions. */ unsigned int supports_subblock_data_units : 1; /* * This field exists only for backwards compatibility reasons and should * only be set by the filesystems that are setting it already. It * contains the filesystem-specific key description prefix that is * accepted for "logon" keys for v1 fscrypt policies. This * functionality is deprecated in favor of the generic prefix * "fscrypt:", which itself is deprecated in favor of the filesystem * keyring ioctls such as FS_IOC_ADD_ENCRYPTION_KEY. Filesystems that * are newly adding fscrypt support should not set this field. */ const char *legacy_key_prefix; /* * Get the fscrypt context of the given inode. * * @inode: the inode whose context to get * @ctx: the buffer into which to get the context * @len: length of the @ctx buffer in bytes * * Return: On success, returns the length of the context in bytes; this * may be less than @len. On failure, returns -ENODATA if the * inode doesn't have a context, -ERANGE if the context is * longer than @len, or another -errno code. */ int (*get_context)(struct inode *inode, void *ctx, size_t len); /* * Set an fscrypt context on the given inode. * * @inode: the inode whose context to set. The inode won't already have * an fscrypt context. * @ctx: the context to set * @len: length of @ctx in bytes (at most FSCRYPT_SET_CONTEXT_MAX_SIZE) * @fs_data: If called from fscrypt_set_context(), this will be the * value the filesystem passed to fscrypt_set_context(). * Otherwise (i.e. when called from * FS_IOC_SET_ENCRYPTION_POLICY) this will be NULL. * * i_rwsem will be held for write. * * Return: 0 on success, -errno on failure. */ int (*set_context)(struct inode *inode, const void *ctx, size_t len, void *fs_data); /* * Get the dummy fscrypt policy in use on the filesystem (if any). * * Filesystems only need to implement this function if they support the * test_dummy_encryption mount option. * * Return: A pointer to the dummy fscrypt policy, if the filesystem is * mounted with test_dummy_encryption; otherwise NULL. */ const union fscrypt_policy *(*get_dummy_policy)(struct super_block *sb); /* * Check whether a directory is empty. i_rwsem will be held for write. */ bool (*empty_dir)(struct inode *inode); /* * Check whether the filesystem's inode numbers and UUID are stable, * meaning that they will never be changed even by offline operations * such as filesystem shrinking and therefore can be used in the * encryption without the possibility of files becoming unreadable. * * Filesystems only need to implement this function if they want to * support the FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags. These * flags are designed to work around the limitations of UFS and eMMC * inline crypto hardware, and they shouldn't be used in scenarios where * such hardware isn't being used. * * Leaving this NULL is equivalent to always returning false. */ bool (*has_stable_inodes)(struct super_block *sb); /* * Return an array of pointers to the block devices to which the * filesystem may write encrypted file contents, NULL if the filesystem * only has a single such block device, or an ERR_PTR() on error. * * On successful non-NULL return, *num_devs is set to the number of * devices in the returned array. The caller must free the returned * array using kfree(). * * If the filesystem can use multiple block devices (other than block * devices that aren't used for encrypted file contents, such as * external journal devices), and wants to support inline encryption, * then it must implement this function. Otherwise it's not needed. */ struct block_device **(*get_devices)(struct super_block *sb, unsigned int *num_devs); }; int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name, struct dentry *dentry, unsigned int flags); static inline struct fscrypt_inode_info * fscrypt_get_inode_info(const struct inode *inode) { /* * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info(). * I.e., another task may publish ->i_crypt_info concurrently, executing * a RELEASE barrier. We need to use smp_load_acquire() here to safely * ACQUIRE the memory the other task published. */ return smp_load_acquire(&inode->i_crypt_info); } /** * fscrypt_needs_contents_encryption() - check whether an inode needs * contents encryption * @inode: the inode to check * * Return: %true iff the inode is an encrypted regular file and the kernel was * built with fscrypt support. * * If you need to know whether the encrypt bit is set even when the kernel was * built without fscrypt support, you must use IS_ENCRYPTED() directly instead. */ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) { return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode); } /* * When d_splice_alias() moves a directory's no-key alias to its * plaintext alias as a result of the encryption key being added, * DCACHE_NOKEY_NAME must be cleared and there might be an opportunity * to disable d_revalidate. Note that we don't have to support the * inverse operation because fscrypt doesn't allow no-key names to be * the source or target of a rename(). */ static inline void fscrypt_handle_d_move(struct dentry *dentry) { /* * VFS calls fscrypt_handle_d_move even for non-fscrypt * filesystems. */ if (dentry->d_flags & DCACHE_NOKEY_NAME) { dentry->d_flags &= ~DCACHE_NOKEY_NAME; /* * Other filesystem features might be handling dentry * revalidation, in which case it cannot be disabled. */ if (dentry->d_op->d_revalidate == fscrypt_d_revalidate) dentry->d_flags &= ~DCACHE_OP_REVALIDATE; } } /** * fscrypt_is_nokey_name() - test whether a dentry is a no-key name * @dentry: the dentry to check * * This returns true if the dentry is a no-key dentry. A no-key dentry is a * dentry that was created in an encrypted directory that hasn't had its * encryption key added yet. Such dentries may be either positive or negative. * * When a filesystem is asked to create a new filename in an encrypted directory * and the new filename's dentry is a no-key dentry, it must fail the operation * with ENOKEY. This includes ->create(), ->mkdir(), ->mknod(), ->symlink(), * ->rename(), and ->link(). (However, ->rename() and ->link() are already * handled by fscrypt_prepare_rename() and fscrypt_prepare_link().) * * This is necessary because creating a filename requires the directory's * encryption key, but just checking for the key on the directory inode during * the final filesystem operation doesn't guarantee that the key was available * during the preceding dentry lookup. And the key must have already been * available during the dentry lookup in order for it to have been checked * whether the filename already exists in the directory and for the new file's * dentry not to be invalidated due to it incorrectly having the no-key flag. * * Return: %true if the dentry is a no-key name */ static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) { return dentry->d_flags & DCACHE_NOKEY_NAME; } static inline void fscrypt_prepare_dentry(struct dentry *dentry, bool is_nokey_name) { /* * This code tries to only take ->d_lock when necessary to write * to ->d_flags. We shouldn't be peeking on d_flags for * DCACHE_OP_REVALIDATE unlocked, but in the unlikely case * there is a race, the worst it can happen is that we fail to * unset DCACHE_OP_REVALIDATE and pay the cost of an extra * d_revalidate. */ if (is_nokey_name) { spin_lock(&dentry->d_lock); dentry->d_flags |= DCACHE_NOKEY_NAME; spin_unlock(&dentry->d_lock); } else if (dentry->d_flags & DCACHE_OP_REVALIDATE && dentry->d_op->d_revalidate == fscrypt_d_revalidate) { /* * Unencrypted dentries and encrypted dentries where the * key is available are always valid from fscrypt * perspective. Avoid the cost of calling * fscrypt_d_revalidate unnecessarily. */ spin_lock(&dentry->d_lock); dentry->d_flags &= ~DCACHE_OP_REVALIDATE; spin_unlock(&dentry->d_lock); } } /* crypto.c */ void fscrypt_enqueue_decrypt_work(struct work_struct *); struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, unsigned int len, unsigned int offs, gfp_t gfp_flags); int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num, gfp_t gfp_flags); int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len, size_t offs); int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num); static inline bool fscrypt_is_bounce_page(struct page *page) { return page->mapping == NULL; } static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) { return (struct page *)page_private(bounce_page); } static inline bool fscrypt_is_bounce_folio(struct folio *folio) { return folio->mapping == NULL; } static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio) { return bounce_folio->private; } void fscrypt_free_bounce_page(struct page *bounce_page); /* policy.c */ int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg); int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg); int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg); int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg); int fscrypt_has_permitted_context(struct inode *parent, struct inode *child); int fscrypt_context_for_new_inode(void *ctx, struct inode *inode); int fscrypt_set_context(struct inode *inode, void *fs_data); struct fscrypt_dummy_policy { const union fscrypt_policy *policy; }; int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param, struct fscrypt_dummy_policy *dummy_policy); bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1, const struct fscrypt_dummy_policy *p2); void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep, struct super_block *sb); static inline bool fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy) { return dummy_policy->policy != NULL; } static inline void fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) { kfree(dummy_policy->policy); dummy_policy->policy = NULL; } /* keyring.c */ void fscrypt_destroy_keyring(struct super_block *sb); int fscrypt_ioctl_add_key(struct file *filp, void __user *arg); int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg); int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg); int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg); /* keysetup.c */ int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, bool *encrypt_ret); void fscrypt_put_encryption_info(struct inode *inode); void fscrypt_free_inode(struct inode *inode); int fscrypt_drop_inode(struct inode *inode); /* fname.c */ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, u8 *out, unsigned int olen); bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, u32 max_len, u32 *encrypted_len_ret); int fscrypt_setup_filename(struct inode *inode, const struct qstr *iname, int lookup, struct fscrypt_name *fname); static inline void fscrypt_free_filename(struct fscrypt_name *fname) { kfree(fname->crypto_buf.name); } int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, struct fscrypt_str *crypto_str); void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str); int fscrypt_fname_disk_to_usr(const struct inode *inode, u32 hash, u32 minor_hash, const struct fscrypt_str *iname, struct fscrypt_str *oname); bool fscrypt_match_name(const struct fscrypt_name *fname, const u8 *de_name, u32 de_name_len); u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name); /* bio.c */ bool fscrypt_decrypt_bio(struct bio *bio); int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len); /* hooks.c */ int fscrypt_file_open(struct inode *inode, struct file *filp); int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, struct dentry *dentry); int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags); int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, struct fscrypt_name *fname); int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry); int __fscrypt_prepare_readdir(struct inode *dir); int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr); int fscrypt_prepare_setflags(struct inode *inode, unsigned int oldflags, unsigned int flags); int fscrypt_prepare_symlink(struct inode *dir, const char *target, unsigned int len, unsigned int max_len, struct fscrypt_str *disk_link); int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, unsigned int len, struct fscrypt_str *disk_link); const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, unsigned int max_size, struct delayed_call *done); int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat); static inline void fscrypt_set_ops(struct super_block *sb, const struct fscrypt_operations *s_cop) { sb->s_cop = s_cop; } #else /* !CONFIG_FS_ENCRYPTION */ static inline struct fscrypt_inode_info * fscrypt_get_inode_info(const struct inode *inode) { return NULL; } static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) { return false; } static inline void fscrypt_handle_d_move(struct dentry *dentry) { } static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) { return false; } static inline void fscrypt_prepare_dentry(struct dentry *dentry, bool is_nokey_name) { } /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) { } static inline struct page *fscrypt_encrypt_pagecache_blocks(struct page *page, unsigned int len, unsigned int offs, gfp_t gfp_flags) { return ERR_PTR(-EOPNOTSUPP); } static inline int fscrypt_encrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num, gfp_t gfp_flags) { return -EOPNOTSUPP; } static inline int fscrypt_decrypt_pagecache_blocks(struct folio *folio, size_t len, size_t offs) { return -EOPNOTSUPP; } static inline int fscrypt_decrypt_block_inplace(const struct inode *inode, struct page *page, unsigned int len, unsigned int offs, u64 lblk_num) { return -EOPNOTSUPP; } static inline bool fscrypt_is_bounce_page(struct page *page) { return false; } static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) { WARN_ON_ONCE(1); return ERR_PTR(-EINVAL); } static inline bool fscrypt_is_bounce_folio(struct folio *folio) { return false; } static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio) { WARN_ON_ONCE(1); return ERR_PTR(-EINVAL); } static inline void fscrypt_free_bounce_page(struct page *bounce_page) { } /* policy.c */ static inline int fscrypt_ioctl_set_policy(struct file *filp, const void __user *arg) { return -EOPNOTSUPP; } static inline int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg) { return -EOPNOTSUPP; } static inline int fscrypt_ioctl_get_policy_ex(struct file *filp, void __user *arg) { return -EOPNOTSUPP; } static inline int fscrypt_ioctl_get_nonce(struct file *filp, void __user *arg) { return -EOPNOTSUPP; } static inline int fscrypt_has_permitted_context(struct inode *parent, struct inode *child) { return 0; } static inline int fscrypt_set_context(struct inode *inode, void *fs_data) { return -EOPNOTSUPP; } struct fscrypt_dummy_policy { }; static inline int fscrypt_parse_test_dummy_encryption(const struct fs_parameter *param, struct fscrypt_dummy_policy *dummy_policy) { return -EINVAL; } static inline bool fscrypt_dummy_policies_equal(const struct fscrypt_dummy_policy *p1, const struct fscrypt_dummy_policy *p2) { return true; } static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep, struct super_block *sb) { } static inline bool fscrypt_is_dummy_policy_set(const struct fscrypt_dummy_policy *dummy_policy) { return false; } static inline void fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) { } /* keyring.c */ static inline void fscrypt_destroy_keyring(struct super_block *sb) { } static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg) { return -EOPNOTSUPP; } static inline int fscrypt_ioctl_remove_key(struct file *filp, void __user *arg) { return -EOPNOTSUPP; } static inline int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg) { return -EOPNOTSUPP; } static inline int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg) { return -EOPNOTSUPP; } /* keysetup.c */ static inline int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, bool *encrypt_ret) { if (IS_ENCRYPTED(dir)) return -EOPNOTSUPP; return 0; } static inline void fscrypt_put_encryption_info(struct inode *inode) { return; } static inline void fscrypt_free_inode(struct inode *inode) { } static inline int fscrypt_drop_inode(struct inode *inode) { return 0; } /* fname.c */ static inline int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, int lookup, struct fscrypt_name *fname) { if (IS_ENCRYPTED(dir)) return -EOPNOTSUPP; memset(fname, 0, sizeof(*fname)); fname->usr_fname = iname; fname->disk_name.name = (unsigned char *)iname->name; fname->disk_name.len = iname->len; return 0; } static inline void fscrypt_free_filename(struct fscrypt_name *fname) { return; } static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, struct fscrypt_str *crypto_str) { return -EOPNOTSUPP; } static inline void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str) { return; } static inline int fscrypt_fname_disk_to_usr(const struct inode *inode, u32 hash, u32 minor_hash, const struct fscrypt_str *iname, struct fscrypt_str *oname) { return -EOPNOTSUPP; } static inline bool fscrypt_match_name(const struct fscrypt_name *fname, const u8 *de_name, u32 de_name_len) { /* Encryption support disabled; use standard comparison */ if (de_name_len != fname->disk_name.len) return false; return !memcmp(de_name, fname->disk_name.name, fname->disk_name.len); } static inline u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name) { WARN_ON_ONCE(1); return 0; } static inline int fscrypt_d_revalidate(struct inode *dir, const struct qstr *name, struct dentry *dentry, unsigned int flags) { return 1; } /* bio.c */ static inline bool fscrypt_decrypt_bio(struct bio *bio) { return true; } static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len) { return -EOPNOTSUPP; } /* hooks.c */ static inline int fscrypt_file_open(struct inode *inode, struct file *filp) { if (IS_ENCRYPTED(inode)) return -EOPNOTSUPP; return 0; } static inline int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, struct dentry *dentry) { return -EOPNOTSUPP; } static inline int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) { return -EOPNOTSUPP; } static inline int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, struct fscrypt_name *fname) { return -EOPNOTSUPP; } static inline int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry) { return -EOPNOTSUPP; } static inline int __fscrypt_prepare_readdir(struct inode *dir) { return -EOPNOTSUPP; } static inline int __fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr) { return -EOPNOTSUPP; } static inline int fscrypt_prepare_setflags(struct inode *inode, unsigned int oldflags, unsigned int flags) { return 0; } static inline int fscrypt_prepare_symlink(struct inode *dir, const char *target, unsigned int len, unsigned int max_len, struct fscrypt_str *disk_link) { if (IS_ENCRYPTED(dir)) return -EOPNOTSUPP; disk_link->name = (unsigned char *)target; disk_link->len = len + 1; if (disk_link->len > max_len) return -ENAMETOOLONG; return 0; } static inline int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, unsigned int len, struct fscrypt_str *disk_link) { return -EOPNOTSUPP; } static inline const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, unsigned int max_size, struct delayed_call *done) { return ERR_PTR(-EOPNOTSUPP); } static inline int fscrypt_symlink_getattr(const struct path *path, struct kstat *stat) { return -EOPNOTSUPP; } static inline void fscrypt_set_ops(struct super_block *sb, const struct fscrypt_operations *s_cop) { } #endif /* !CONFIG_FS_ENCRYPTION */ /* inline_crypt.c */ #ifdef CONFIG_FS_ENCRYPTION_INLINE_CRYPT bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode); void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode, u64 first_lblk, gfp_t gfp_mask); void fscrypt_set_bio_crypt_ctx_bh(struct bio *bio, const struct buffer_head *first_bh, gfp_t gfp_mask); bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, u64 next_lblk); bool fscrypt_mergeable_bio_bh(struct bio *bio, const struct buffer_head *next_bh); bool fscrypt_dio_supported(struct inode *inode); u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks); #else /* CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ static inline bool __fscrypt_inode_uses_inline_crypto(const struct inode *inode) { return false; } static inline void fscrypt_set_bio_crypt_ctx(struct bio *bio, const struct inode *inode, u64 first_lblk, gfp_t gfp_mask) { } static inline void fscrypt_set_bio_crypt_ctx_bh( struct bio *bio, const struct buffer_head *first_bh, gfp_t gfp_mask) { } static inline bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, u64 next_lblk) { return true; } static inline bool fscrypt_mergeable_bio_bh(struct bio *bio, const struct buffer_head *next_bh) { return true; } static inline bool fscrypt_dio_supported(struct inode *inode) { return !fscrypt_needs_contents_encryption(inode); } static inline u64 fscrypt_limit_io_blocks(const struct inode *inode, u64 lblk, u64 nr_blocks) { return nr_blocks; } #endif /* !CONFIG_FS_ENCRYPTION_INLINE_CRYPT */ /** * fscrypt_inode_uses_inline_crypto() - test whether an inode uses inline * encryption * @inode: an inode. If encrypted, its key must be set up. * * Return: true if the inode requires file contents encryption and if the * encryption should be done in the block layer via blk-crypto rather * than in the filesystem layer. */ static inline bool fscrypt_inode_uses_inline_crypto(const struct inode *inode) { return fscrypt_needs_contents_encryption(inode) && __fscrypt_inode_uses_inline_crypto(inode); } /** * fscrypt_inode_uses_fs_layer_crypto() - test whether an inode uses fs-layer * encryption * @inode: an inode. If encrypted, its key must be set up. * * Return: true if the inode requires file contents encryption and if the * encryption should be done in the filesystem layer rather than in the * block layer via blk-crypto. */ static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode) { return fscrypt_needs_contents_encryption(inode) && !__fscrypt_inode_uses_inline_crypto(inode); } /** * fscrypt_has_encryption_key() - check whether an inode has had its key set up * @inode: the inode to check * * Return: %true if the inode has had its encryption key set up, else %false. * * Usually this should be preceded by fscrypt_get_encryption_info() to try to * set up the key first. */ static inline bool fscrypt_has_encryption_key(const struct inode *inode) { return fscrypt_get_inode_info(inode) != NULL; } /** * fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted * directory * @old_dentry: an existing dentry for the inode being linked * @dir: the target directory * @dentry: negative dentry for the target filename * * A new link can only be added to an encrypted directory if the directory's * encryption key is available --- since otherwise we'd have no way to encrypt * the filename. * * We also verify that the link will not violate the constraint that all files * in an encrypted directory tree use the same encryption policy. * * Return: 0 on success, -ENOKEY if the directory's encryption key is missing, * -EXDEV if the link would result in an inconsistent encryption policy, or * another -errno code. */ static inline int fscrypt_prepare_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) { if (IS_ENCRYPTED(dir)) return __fscrypt_prepare_link(d_inode(old_dentry), dir, dentry); return 0; } /** * fscrypt_prepare_rename() - prepare for a rename between possibly-encrypted * directories * @old_dir: source directory * @old_dentry: dentry for source file * @new_dir: target directory * @new_dentry: dentry for target location (may be negative unless exchanging) * @flags: rename flags (we care at least about %RENAME_EXCHANGE) * * Prepare for ->rename() where the source and/or target directories may be * encrypted. A new link can only be added to an encrypted directory if the * directory's encryption key is available --- since otherwise we'd have no way * to encrypt the filename. A rename to an existing name, on the other hand, * *is* cryptographically possible without the key. However, we take the more * conservative approach and just forbid all no-key renames. * * We also verify that the rename will not violate the constraint that all files * in an encrypted directory tree use the same encryption policy. * * Return: 0 on success, -ENOKEY if an encryption key is missing, -EXDEV if the * rename would cause inconsistent encryption policies, or another -errno code. */ static inline int fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) { if (IS_ENCRYPTED(old_dir) || IS_ENCRYPTED(new_dir)) return __fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry, flags); return 0; } /** * fscrypt_prepare_lookup() - prepare to lookup a name in a possibly-encrypted * directory * @dir: directory being searched * @dentry: filename being looked up * @fname: (output) the name to use to search the on-disk directory * * Prepare for ->lookup() in a directory which may be encrypted by determining * the name that will actually be used to search the directory on-disk. If the * directory's encryption policy is supported by this kernel and its encryption * key is available, then the lookup is assumed to be by plaintext name; * otherwise, it is assumed to be by no-key name. * * This will set DCACHE_NOKEY_NAME on the dentry if the lookup is by no-key * name. In this case the filesystem must assign the dentry a dentry_operations * which contains fscrypt_d_revalidate (or contains a d_revalidate method that * calls fscrypt_d_revalidate), so that the dentry will be invalidated if the * directory's encryption key is later added. * * Return: 0 on success; -ENOENT if the directory's key is unavailable but the * filename isn't a valid no-key name, so a negative dentry should be created; * or another -errno code. */ static inline int fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, struct fscrypt_name *fname) { if (IS_ENCRYPTED(dir)) return __fscrypt_prepare_lookup(dir, dentry, fname); memset(fname, 0, sizeof(*fname)); fname->usr_fname = &dentry->d_name; fname->disk_name.name = (unsigned char *)dentry->d_name.name; fname->disk_name.len = dentry->d_name.len; fscrypt_prepare_dentry(dentry, false); return 0; } /** * fscrypt_prepare_readdir() - prepare to read a possibly-encrypted directory * @dir: the directory inode * * If the directory is encrypted and it doesn't already have its encryption key * set up, try to set it up so that the filenames will be listed in plaintext * form rather than in no-key form. * * Return: 0 on success; -errno on error. Note that the encryption key being * unavailable is not considered an error. It is also not an error if * the encryption policy is unsupported by this kernel; that is treated * like the key being unavailable, so that files can still be deleted. */ static inline int fscrypt_prepare_readdir(struct inode *dir) { if (IS_ENCRYPTED(dir)) return __fscrypt_prepare_readdir(dir); return 0; } /** * fscrypt_prepare_setattr() - prepare to change a possibly-encrypted inode's * attributes * @dentry: dentry through which the inode is being changed * @attr: attributes to change * * Prepare for ->setattr() on a possibly-encrypted inode. On an encrypted file, * most attribute changes are allowed even without the encryption key. However, * without the encryption key we do have to forbid truncates. This is needed * because the size being truncated to may not be a multiple of the filesystem * block size, and in that case we'd have to decrypt the final block, zero the * portion past i_size, and re-encrypt it. (We *could* allow truncating to a * filesystem block boundary, but it's simpler to just forbid all truncates --- * and we already forbid all other contents modifications without the key.) * * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code * if a problem occurred while setting up the encryption key. */ static inline int fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr) { if (IS_ENCRYPTED(d_inode(dentry))) return __fscrypt_prepare_setattr(dentry, attr); return 0; } /** * fscrypt_encrypt_symlink() - encrypt the symlink target if needed * @inode: symlink inode * @target: plaintext symlink target * @len: length of @target excluding null terminator * @disk_link: (in/out) the on-disk symlink target being prepared * * If the symlink target needs to be encrypted, then this function encrypts it * into @disk_link->name. fscrypt_prepare_symlink() must have been called * previously to compute @disk_link->len. If the filesystem did not allocate a * buffer for @disk_link->name after calling fscrypt_prepare_link(), then one * will be kmalloc()'ed and the filesystem will be responsible for freeing it. * * Return: 0 on success, -errno on failure */ static inline int fscrypt_encrypt_symlink(struct inode *inode, const char *target, unsigned int len, struct fscrypt_str *disk_link) { if (IS_ENCRYPTED(inode)) return __fscrypt_encrypt_symlink(inode, target, len, disk_link); return 0; } /* If *pagep is a bounce page, free it and set *pagep to the pagecache page */ static inline void fscrypt_finalize_bounce_page(struct page **pagep) { struct page *page = *pagep; if (fscrypt_is_bounce_page(page)) { *pagep = fscrypt_pagecache_page(page); fscrypt_free_bounce_page(page); } } #endif /* _LINUX_FSCRYPT_H */