diff options
Diffstat (limited to 'include/linux/fscrypt.h')
| -rw-r--r-- | include/linux/fscrypt.h | 264 |
1 files changed, 133 insertions, 131 deletions
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 991ff8575d0e..2ea1387bb497 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -15,13 +15,12 @@ #include <linux/fs.h> #include <linux/mm.h> -#include <linux/parser.h> #include <linux/slab.h> #include <uapi/linux/fscrypt.h> #define FS_CRYPTO_BLOCK_SIZE 16 -union fscrypt_context; +union fscrypt_policy; struct fscrypt_info; struct seq_file; @@ -36,7 +35,7 @@ struct fscrypt_name { u32 hash; u32 minor_hash; struct fscrypt_str crypto_buf; - bool is_ciphertext_name; + bool is_nokey_name; }; #define FSTR_INIT(n, l) { .name = n, .len = l } @@ -62,8 +61,7 @@ struct fscrypt_operations { int (*get_context)(struct inode *inode, void *ctx, size_t len); int (*set_context)(struct inode *inode, const void *ctx, size_t len, void *fs_data); - const union fscrypt_context *(*get_dummy_context)( - struct super_block *sb); + const union fscrypt_policy *(*get_dummy_policy)(struct super_block *sb); bool (*empty_dir)(struct inode *inode); unsigned int max_namelen; bool (*has_stable_inodes)(struct super_block *sb); @@ -77,7 +75,7 @@ struct fscrypt_operations { static inline struct fscrypt_info *fscrypt_get_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. @@ -101,24 +99,45 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) return IS_ENCRYPTED(inode) && S_ISREG(inode->i_mode); } -static inline const union fscrypt_context * -fscrypt_get_dummy_context(struct super_block *sb) +/* + * 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) { - if (!sb->s_cop->get_dummy_context) - return NULL; - return sb->s_cop->get_dummy_context(sb); + dentry->d_flags &= ~DCACHE_NOKEY_NAME; } -/* - * When d_splice_alias() moves a directory's encrypted alias to its decrypted - * alias as a result of the encryption key being added, DCACHE_ENCRYPTED_NAME - * must be cleared. Note that we don't have to support arbitrary moves of this - * flag because fscrypt doesn't allow encrypted aliases to be the source or - * target of a rename(). +/** + * 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 void fscrypt_handle_d_move(struct dentry *dentry) +static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) { - dentry->d_flags &= ~DCACHE_ENCRYPTED_NAME; + return dentry->d_flags & DCACHE_NOKEY_NAME; } /* crypto.c */ @@ -156,23 +175,21 @@ 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_inherit_context(struct inode *parent, struct inode *child, - void *fs_data, bool preload); +int fscrypt_set_context(struct inode *inode, void *fs_data); -struct fscrypt_dummy_context { - const union fscrypt_context *ctx; +struct fscrypt_dummy_policy { + const union fscrypt_policy *policy; }; -int fscrypt_set_test_dummy_encryption(struct super_block *sb, - const substring_t *arg, - struct fscrypt_dummy_context *dummy_ctx); +int fscrypt_set_test_dummy_encryption(struct super_block *sb, const char *arg, + struct fscrypt_dummy_policy *dummy_policy); void fscrypt_show_test_dummy_encryption(struct seq_file *seq, char sep, struct super_block *sb); static inline void -fscrypt_free_dummy_context(struct fscrypt_dummy_context *dummy_ctx) +fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) { - kfree(dummy_ctx->ctx); - dummy_ctx->ctx = NULL; + kfree(dummy_policy->policy); + dummy_policy->policy = NULL; } /* keyring.c */ @@ -183,7 +200,8 @@ 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); void fscrypt_free_inode(struct inode *inode); int fscrypt_drop_inode(struct inode *inode); @@ -197,7 +215,7 @@ static inline void fscrypt_free_filename(struct fscrypt_name *fname) kfree(fname->crypto_buf.name); } -int fscrypt_fname_alloc_buffer(const struct inode *inode, u32 max_encrypted_len, +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, @@ -207,6 +225,7 @@ 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); @@ -222,11 +241,13 @@ 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_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, unsigned int len, - unsigned int max_len, - struct fscrypt_str *disk_link); +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, @@ -249,14 +270,13 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) return false; } -static inline const union fscrypt_context * -fscrypt_get_dummy_context(struct super_block *sb) +static inline void fscrypt_handle_d_move(struct dentry *dentry) { - return NULL; } -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 */ @@ -340,14 +360,12 @@ static inline int fscrypt_has_permitted_context(struct inode *parent, return 0; } -static inline int fscrypt_inherit_context(struct inode *parent, - struct inode *child, - void *fs_data, bool preload) +static inline int fscrypt_set_context(struct inode *inode, void *fs_data) { return -EOPNOTSUPP; } -struct fscrypt_dummy_context { +struct fscrypt_dummy_policy { }; static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq, @@ -357,7 +375,7 @@ static inline void fscrypt_show_test_dummy_encryption(struct seq_file *seq, } static inline void -fscrypt_free_dummy_context(struct fscrypt_dummy_context *dummy_ctx) +fscrypt_free_dummy_policy(struct fscrypt_dummy_policy *dummy_policy) { } @@ -389,9 +407,14 @@ static inline int fscrypt_ioctl_get_key_status(struct file *filp, } /* keysetup.c */ -static inline int fscrypt_get_encryption_info(struct inode *inode) + +static inline int fscrypt_prepare_new_inode(struct inode *dir, + struct inode *inode, + bool *encrypt_ret) { - return -EOPNOTSUPP; + if (IS_ENCRYPTED(dir)) + return -EOPNOTSUPP; + return 0; } static inline void fscrypt_put_encryption_info(struct inode *inode) @@ -428,8 +451,7 @@ static inline void fscrypt_free_filename(struct fscrypt_name *fname) return; } -static inline int fscrypt_fname_alloc_buffer(const struct inode *inode, - u32 max_encrypted_len, +static inline int fscrypt_fname_alloc_buffer(u32 max_encrypted_len, struct fscrypt_str *crypto_str) { return -EOPNOTSUPP; @@ -464,6 +486,12 @@ static inline u64 fscrypt_fname_siphash(const struct inode *dir, return 0; } +static inline int fscrypt_d_revalidate(struct dentry *dentry, + unsigned int flags) +{ + return 1; +} + /* bio.c */ static inline void fscrypt_decrypt_bio(struct bio *bio) { @@ -506,6 +534,17 @@ static inline int __fscrypt_prepare_lookup(struct inode *dir, 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) @@ -513,15 +552,21 @@ static inline int fscrypt_prepare_setflags(struct inode *inode, return 0; } -static inline int __fscrypt_prepare_symlink(struct inode *dir, - unsigned int len, - unsigned int max_len, - struct fscrypt_str *disk_link) +static inline int fscrypt_prepare_symlink(struct inode *dir, + const char *target, + unsigned int len, + unsigned int max_len, + struct fscrypt_str *disk_link) { - return -EOPNOTSUPP; + 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, @@ -639,32 +684,6 @@ static inline bool fscrypt_has_encryption_key(const struct inode *inode) } /** - * 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; -} - -/** * fscrypt_prepare_link() - prepare to link an inode into a possibly-encrypted * directory * @old_dentry: an existing dentry for the inode being linked @@ -673,8 +692,7 @@ 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. @@ -734,17 +752,20 @@ static inline int fscrypt_prepare_rename(struct inode *old_dir, * @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. Lookups - * can be done with or without the directory's encryption key; without the key, - * filenames are presented in encrypted form. Therefore, we'll try to set up - * the directory's encryption key, but even without it the lookup can continue. + * 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 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 key is unavailable but the filename isn't a - * correctly formed encoded ciphertext name, so a negative dentry should be - * created; or another -errno code. + * 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, @@ -761,6 +782,26 @@ static inline int fscrypt_prepare_lookup(struct inode *dir, } /** + * 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 @@ -781,47 +822,8 @@ 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)); - return 0; -} - -/** - * fscrypt_prepare_symlink() - prepare to create a possibly-encrypted symlink - * @dir: directory in which the symlink is being created - * @target: plaintext symlink target - * @len: length of @target excluding null terminator - * @max_len: space the filesystem has available to store the symlink target - * @disk_link: (out) the on-disk symlink target being prepared - * - * This function computes the size the symlink target will require on-disk, - * stores it in @disk_link->len, and validates it against @max_len. An - * encrypted symlink may be longer than the original. - * - * Additionally, @disk_link->name is set to @target if the symlink will be - * unencrypted, but left NULL if the symlink will be encrypted. For encrypted - * symlinks, the filesystem must call fscrypt_encrypt_symlink() to create the - * on-disk target later. (The reason for the two-step process is that some - * filesystems need to know the size of the symlink target before creating the - * inode, e.g. to determine whether it will be a "fast" or "slow" symlink.) - * - * Return: 0 on success, -ENAMETOOLONG if the symlink target is too long, - * -ENOKEY if the encryption key is missing, or another -errno code if a problem - * occurred while setting up the encryption key. - */ -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) || fscrypt_get_dummy_context(dir->i_sb) != NULL) - return __fscrypt_prepare_symlink(dir, len, max_len, disk_link); - - disk_link->name = (unsigned char *)target; - disk_link->len = len + 1; - if (disk_link->len > max_len) - return -ENAMETOOLONG; + if (IS_ENCRYPTED(d_inode(dentry))) + return __fscrypt_prepare_setattr(dentry, attr); return 0; } |