diff options
Diffstat (limited to 'include/linux/fscrypt.h')
| -rw-r--r-- | include/linux/fscrypt.h | 468 |
1 files changed, 380 insertions, 88 deletions
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a8f7a43f031b..56fad33043d5 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -18,10 +18,21 @@ #include <linux/slab.h> #include <uapi/linux/fscrypt.h> -#define FS_CRYPTO_BLOCK_SIZE 16 +/* + * 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 fscrypt_inode_info; +struct fs_parameter; struct seq_file; struct fscrypt_str { @@ -47,35 +58,148 @@ struct fscrypt_name { #define FSCRYPT_SET_CONTEXT_MAX_SIZE 40 #ifdef CONFIG_FS_ENCRYPTION -/* - * fscrypt superblock flags - */ -#define FS_CFLG_OWN_PAGES (1U << 1) -/* - * crypto operations for filesystems - */ +/* Crypto operations for filesystems */ struct fscrypt_operations { - unsigned int flags; - const char *key_prefix; + + /* + * 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); - unsigned int max_namelen; + + /* + * 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); - void (*get_ino_and_lblk_bits)(struct super_block *sb, - int *ino_bits_ret, int *lblk_bits_ret); - int (*get_num_devices)(struct super_block *sb); - void (*get_devices)(struct super_block *sb, - struct request_queue **devs); + + /* + * 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) +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_get_encryption_info(). + * 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. @@ -100,30 +224,100 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) } /* - * 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(). + * 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) { - dentry->d_flags &= ~DCACHE_NOKEY_NAME; + /* + * 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); +struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio, + size_t len, size_t 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_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); @@ -138,6 +332,16 @@ 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 */ @@ -146,16 +350,24 @@ 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_set_test_dummy_encryption(struct super_block *sb, const char *arg, - struct fscrypt_dummy_policy *dummy_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) { @@ -164,14 +376,13 @@ fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) } /* keyring.c */ -void fscrypt_sb_free(struct super_block *sb); +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_get_encryption_info(struct inode *inode); int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, bool *encrypt_ret); void fscrypt_put_encryption_info(struct inode *inode); @@ -179,6 +390,10 @@ 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); @@ -197,10 +412,9 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, 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 */ -void fscrypt_decrypt_bio(struct bio *bio); +bool fscrypt_decrypt_bio(struct bio *bio); int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, sector_t pblk, unsigned int len); @@ -213,6 +427,9 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_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, @@ -223,6 +440,7 @@ int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, 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) { @@ -230,7 +448,8 @@ static inline void fscrypt_set_ops(struct super_block *sb, } #else /* !CONFIG_FS_ENCRYPTION */ -static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode) +static inline struct fscrypt_inode_info * +fscrypt_get_inode_info(const struct inode *inode) { return NULL; } @@ -244,15 +463,23 @@ 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) +static inline struct page *fscrypt_encrypt_pagecache_blocks(struct folio *folio, + size_t len, size_t offs, gfp_t gfp_flags) { return ERR_PTR(-EOPNOTSUPP); } @@ -266,9 +493,8 @@ static inline int fscrypt_encrypt_block_inplace(const struct inode *inode, return -EOPNOTSUPP; } -static inline int fscrypt_decrypt_pagecache_blocks(struct page *page, - unsigned int len, - unsigned int offs) +static inline int fscrypt_decrypt_pagecache_blocks(struct folio *folio, + size_t len, size_t offs) { return -EOPNOTSUPP; } @@ -292,6 +518,17 @@ static inline struct page *fscrypt_pagecache_page(struct page *bounce_page) 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) { } @@ -333,19 +570,39 @@ static inline int fscrypt_set_context(struct inode *inode, void *fs_data) 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_sb_free(struct super_block *sb) +static inline void fscrypt_destroy_keyring(struct super_block *sb) { } @@ -372,10 +629,6 @@ static inline int fscrypt_ioctl_get_key_status(struct file *filp, } /* keysetup.c */ -static inline int fscrypt_get_encryption_info(struct inode *inode) -{ - return -EOPNOTSUPP; -} static inline int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode, @@ -455,15 +708,16 @@ static inline u64 fscrypt_fname_siphash(const struct inode *dir, return 0; } -static inline int fscrypt_d_revalidate(struct dentry *dentry, - unsigned int flags) +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 void fscrypt_decrypt_bio(struct bio *bio) +static inline bool fscrypt_decrypt_bio(struct bio *bio) { + return true; } static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk, @@ -503,6 +757,23 @@ static inline int __fscrypt_prepare_lookup(struct inode *dir, 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) @@ -541,6 +812,12 @@ static inline const char *fscrypt_get_symlink(struct inode *inode, 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) { @@ -567,6 +844,10 @@ bool fscrypt_mergeable_bio(struct bio *bio, const struct inode *inode, 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) @@ -595,6 +876,17 @@ static inline bool fscrypt_mergeable_bio_bh(struct bio *bio, { 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 */ /** @@ -638,33 +930,7 @@ static inline bool fscrypt_inode_uses_fs_layer_crypto(const struct inode *inode) */ static inline bool fscrypt_has_encryption_key(const struct inode *inode) { - return fscrypt_get_info(inode) != NULL; -} - -/** - * fscrypt_require_key() - require an inode's encryption key - * @inode: the inode we need the key for - * - * If the inode is encrypted, set up its encryption key if not already done. - * Then require that the key be present and return -ENOKEY otherwise. - * - * No locks are needed, and the key will live as long as the struct inode --- so - * it won't go away from under you. - * - * 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_require_key(struct inode *inode) -{ - if (IS_ENCRYPTED(inode)) { - int err = fscrypt_get_encryption_info(inode); - - if (err) - return err; - if (!fscrypt_has_encryption_key(inode)) - return -ENOKEY; - } - return 0; + return fscrypt_get_inode_info(inode) != NULL; } /** @@ -676,8 +942,7 @@ static inline int fscrypt_require_key(struct inode *inode) * * 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. Therefore, we first set up the directory's encryption key (if - * not already done) and return an error if it's unavailable. + * 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. @@ -738,11 +1003,15 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir, * * 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 key is available, then the lookup is assumed to be by - * plaintext name; otherwise, it is assumed to be by no-key name. + * 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 also installs a custom ->d_revalidate() method which will invalidate the - * dentry if it was created without the key and the key is later added. + * 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; @@ -759,6 +1028,29 @@ static inline int fscrypt_prepare_lookup(struct inode *dir, 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; } @@ -783,8 +1075,8 @@ static inline int fscrypt_prepare_lookup(struct inode *dir, static inline int fscrypt_prepare_setattr(struct dentry *dentry, struct iattr *attr) { - if (attr->ia_valid & ATTR_SIZE) - return fscrypt_require_key(d_inode(dentry)); + if (IS_ENCRYPTED(d_inode(dentry))) + return __fscrypt_prepare_setattr(dentry, attr); return 0; } |