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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>
- #include <linux/android_kabi.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_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
- /*
- * If set, the fscrypt bounce page pool won't be allocated (unless another
- * filesystem needs it). Set this if the filesystem always uses its own bounce
- * pages for writes and therefore won't need the fscrypt bounce page pool.
- */
- #define FS_CFLG_OWN_PAGES (1U << 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.
- */
- #define FS_CFLG_SUPPORTS_SUBBLOCK_DATA_UNITS (1U << 2)
- /* Crypto operations for filesystems */
- struct fscrypt_operations {
- /* Set of optional flags; see above for allowed flags */
- unsigned int flags;
- /*
- * If set, this is a filesystem-specific key description prefix that
- * will be accepted for "logon" keys for v1 fscrypt policies, in
- * addition to the generic prefix "fscrypt:". This functionality is
- * deprecated, so new filesystems shouldn't set this field.
- */
- const char *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);
- /*
- * Get the number of bits that the filesystem uses to represent inode
- * numbers and file logical block numbers.
- *
- * By default, both of these are assumed to be 64-bit. This function
- * can be implemented to declare that either or both of these numbers is
- * shorter, which may allow the use of the
- * FSCRYPT_POLICY_FLAG_IV_INO_LBLK_{32,64} flags and/or the use of
- * inline crypto hardware whose maximum DUN length is less than 64 bits
- * (e.g., eMMC v5.2 spec compliant hardware). This function only needs
- * to be implemented if support for one of these features is needed.
- */
- void (*get_ino_and_lblk_bits)(struct super_block *sb,
- int *ino_bits_ret, int *lblk_bits_ret);
- /*
- * 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);
- ANDROID_KABI_RESERVE(1);
- ANDROID_KABI_RESERVE(2);
- ANDROID_KABI_RESERVE(3);
- ANDROID_KABI_RESERVE(4);
- ANDROID_OEM_DATA_ARRAY(1, 4);
- };
- static inline struct fscrypt_info *fscrypt_get_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. Note that we don't have to support arbitrary moves of this flag
- * 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)
- {
- dentry->d_flags &= ~DCACHE_NOKEY_NAME;
- }
- /**
- * 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;
- }
- /* 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);
- }
- 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);
- int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags);
- /* 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_info *fscrypt_get_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;
- }
- /* 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 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 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 */
- #if IS_ENABLED(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_DM_DEFAULT_KEY)
- static inline bool
- fscrypt_inode_should_skip_dm_default_key(const struct inode *inode)
- {
- return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode);
- }
- #else
- static inline bool
- fscrypt_inode_should_skip_dm_default_key(const struct inode *inode)
- {
- return false;
- }
- #endif
- /**
- * 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_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;
- 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 */
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