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Diffstat (limited to 'include/linux/fscrypt.h')
| -rw-r--r-- | include/linux/fscrypt.h | 1036 |
1 files changed, 1036 insertions, 0 deletions
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h new file mode 100644 index 000000000..4f5f8a651 --- /dev/null +++ b/include/linux/fscrypt.h @@ -0,0 +1,1036 @@ +/* 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_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) + +/* 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); +}; + +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 page *page, unsigned int len, + unsigned int 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_add_test_dummy_key(struct super_block *sb, + const struct fscrypt_dummy_policy *dummy_policy); +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_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 page *page, + unsigned int len, + unsigned int 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_add_test_dummy_key(struct super_block *sb, + const struct fscrypt_dummy_policy *dummy_policy) +{ + return 0; +} + +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_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_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 */ |