diff options
| -rw-r--r-- | fs/crypto/fname.c | 8 | ||||
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 56 | ||||
| -rw-r--r-- | fs/crypto/hooks.c | 55 | ||||
| -rw-r--r-- | fs/crypto/keyring.c | 10 | ||||
| -rw-r--r-- | fs/crypto/keysetup.c | 44 | ||||
| -rw-r--r-- | fs/crypto/policy.c | 27 | ||||
| -rw-r--r-- | fs/ext4/dir.c | 16 | ||||
| -rw-r--r-- | fs/ext4/namei.c | 13 | ||||
| -rw-r--r-- | fs/f2fs/dir.c | 10 | ||||
| -rw-r--r-- | fs/f2fs/f2fs.h | 2 | ||||
| -rw-r--r-- | fs/ubifs/dir.c | 28 | ||||
| -rw-r--r-- | include/linux/fscrypt.h | 112 | ||||
| -rw-r--r-- | include/uapi/linux/fscrypt.h | 5 |
13 files changed, 227 insertions, 159 deletions
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c index 1fbe6c24d705..988dadf7a94d 100644 --- a/fs/crypto/fname.c +++ b/fs/crypto/fname.c @@ -404,7 +404,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, fname->disk_name.len = iname->len; return 0; } - ret = fscrypt_get_encryption_info(dir); + ret = fscrypt_get_encryption_info(dir, lookup); if (ret) return ret; @@ -560,7 +560,11 @@ int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags) return -ECHILD; dir = dget_parent(dentry); - err = fscrypt_get_encryption_info(d_inode(dir)); + /* + * Pass allow_unsupported=true, so that files with an unsupported + * encryption policy can be deleted. + */ + err = fscrypt_get_encryption_info(d_inode(dir), true); valid = !fscrypt_has_encryption_key(d_inode(dir)); dput(dir); diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 4f5806a3b73d..f0bed6b06fa6 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -25,6 +25,9 @@ #define FSCRYPT_CONTEXT_V1 1 #define FSCRYPT_CONTEXT_V2 2 +/* Keep this in sync with include/uapi/linux/fscrypt.h */ +#define FSCRYPT_MODE_MAX FSCRYPT_MODE_ADIANTUM + struct fscrypt_context_v1 { u8 version; /* FSCRYPT_CONTEXT_V1 */ u8 contents_encryption_mode; @@ -436,16 +439,9 @@ struct fscrypt_master_key { * FS_IOC_REMOVE_ENCRYPTION_KEY can be retried, or * FS_IOC_ADD_ENCRYPTION_KEY can add the secret again. * - * Locking: protected by key->sem (outer) and mk_secret_sem (inner). - * The reason for two locks is that key->sem also protects modifying - * mk_users, which ranks it above the semaphore for the keyring key - * type, which is in turn above page faults (via keyring_read). But - * sometimes filesystems call fscrypt_get_encryption_info() from within - * a transaction, which ranks it below page faults. So we need a - * separate lock which protects mk_secret but not also mk_users. + * Locking: protected by this master key's key->sem. */ struct fscrypt_master_key_secret mk_secret; - struct rw_semaphore mk_secret_sem; /* * For v1 policy keys: an arbitrary key descriptor which was assigned by @@ -464,8 +460,8 @@ struct fscrypt_master_key { * * This is NULL for v1 policy keys; those can only be added by root. * - * Locking: in addition to this keyrings own semaphore, this is - * protected by the master key's key->sem, so we can do atomic + * Locking: in addition to this keyring's own semaphore, this is + * protected by this master key's key->sem, so we can do atomic * search+insert. It can also be searched without taking any locks, but * in that case the returned key may have already been removed. */ @@ -491,9 +487,9 @@ struct fscrypt_master_key { * Per-mode encryption keys for the various types of encryption policies * that use them. Allocated and derived on-demand. */ - struct fscrypt_prepared_key mk_direct_keys[__FSCRYPT_MODE_MAX + 1]; - struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[__FSCRYPT_MODE_MAX + 1]; - struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[__FSCRYPT_MODE_MAX + 1]; + struct fscrypt_prepared_key mk_direct_keys[FSCRYPT_MODE_MAX + 1]; + struct fscrypt_prepared_key mk_iv_ino_lblk_64_keys[FSCRYPT_MODE_MAX + 1]; + struct fscrypt_prepared_key mk_iv_ino_lblk_32_keys[FSCRYPT_MODE_MAX + 1]; /* Hash key for inode numbers. Initialized only when needed. */ siphash_key_t mk_ino_hash_key; @@ -507,9 +503,9 @@ is_master_key_secret_present(const struct fscrypt_master_key_secret *secret) /* * The READ_ONCE() is only necessary for fscrypt_drop_inode() and * fscrypt_key_describe(). These run in atomic context, so they can't - * take ->mk_secret_sem and thus 'secret' can change concurrently which - * would be a data race. But they only need to know whether the secret - * *was* present at the time of check, so READ_ONCE() suffices. + * take the key semaphore and thus 'secret' can change concurrently + * which would be a data race. But they only need to know whether the + * secret *was* present at the time of check, so READ_ONCE() suffices. */ return READ_ONCE(secret->size) != 0; } @@ -575,6 +571,34 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci, void fscrypt_hash_inode_number(struct fscrypt_info *ci, const struct fscrypt_master_key *mk); +int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported); + +/** + * 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, false); + + if (err) + return err; + if (!fscrypt_has_encryption_key(inode)) + return -ENOKEY; + } + return 0; +} + /* keysetup_v1.c */ void fscrypt_put_direct_key(struct fscrypt_direct_key *dk); diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 20b0df47fe6a..79570e0e8e61 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -54,15 +54,12 @@ EXPORT_SYMBOL_GPL(fscrypt_file_open); int __fscrypt_prepare_link(struct inode *inode, struct inode *dir, struct dentry *dentry) { - int err; - - err = fscrypt_require_key(dir); - if (err) - return err; - - /* ... in case we looked up no-key name before key was added */ - if (dentry->d_flags & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(dentry)) return -ENOKEY; + /* + * We don't need to separately check that the directory inode's key is + * available, as it's implied by the dentry not being a no-key name. + */ if (!fscrypt_has_permitted_context(dir, inode)) return -EXDEV; @@ -75,19 +72,13 @@ int __fscrypt_prepare_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) { - int err; - - err = fscrypt_require_key(old_dir); - if (err) - return err; - - err = fscrypt_require_key(new_dir); - if (err) - return err; - - /* ... in case we looked up no-key name(s) before key was added */ - if ((old_dentry->d_flags | new_dentry->d_flags) & DCACHE_NOKEY_NAME) + if (fscrypt_is_nokey_name(old_dentry) || + fscrypt_is_nokey_name(new_dentry)) return -ENOKEY; + /* + * We don't need to separately check that the directory inodes' keys are + * available, as it's implied by the dentries not being no-key names. + */ if (old_dir != new_dir) { if (IS_ENCRYPTED(new_dir) && @@ -123,6 +114,20 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, } EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup); +int __fscrypt_prepare_readdir(struct inode *dir) +{ + return fscrypt_get_encryption_info(dir, true); +} +EXPORT_SYMBOL_GPL(__fscrypt_prepare_readdir); + +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; +} +EXPORT_SYMBOL_GPL(__fscrypt_prepare_setattr); + /** * fscrypt_prepare_setflags() - prepare to change flags with FS_IOC_SETFLAGS * @inode: the inode on which flags are being changed @@ -138,6 +143,7 @@ int fscrypt_prepare_setflags(struct inode *inode, unsigned int oldflags, unsigned int flags) { struct fscrypt_info *ci; + struct key *key; struct fscrypt_master_key *mk; int err; @@ -153,13 +159,14 @@ int fscrypt_prepare_setflags(struct inode *inode, ci = inode->i_crypt_info; if (ci->ci_policy.version != FSCRYPT_POLICY_V2) return -EINVAL; - mk = ci->ci_master_key->payload.data[0]; - down_read(&mk->mk_secret_sem); + key = ci->ci_master_key; + mk = key->payload.data[0]; + down_read(&key->sem); if (is_master_key_secret_present(&mk->mk_secret)) err = fscrypt_derive_dirhash_key(ci, mk); else err = -ENOKEY; - up_read(&mk->mk_secret_sem); + up_read(&key->sem); return err; } return 0; @@ -325,7 +332,7 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, * Try to set up the symlink's encryption key, but we can continue * regardless of whether the key is available or not. */ - err = fscrypt_get_encryption_info(inode); + err = fscrypt_get_encryption_info(inode, false); if (err) return ERR_PTR(err); has_key = fscrypt_has_encryption_key(inode); diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index 53cc552a7b8f..0b3ffbb4faf4 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -44,7 +44,7 @@ static void free_master_key(struct fscrypt_master_key *mk) wipe_master_key_secret(&mk->mk_secret); - for (i = 0; i <= __FSCRYPT_MODE_MAX; i++) { + for (i = 0; i <= FSCRYPT_MODE_MAX; i++) { fscrypt_destroy_prepared_key(&mk->mk_direct_keys[i]); fscrypt_destroy_prepared_key(&mk->mk_iv_ino_lblk_64_keys[i]); fscrypt_destroy_prepared_key(&mk->mk_iv_ino_lblk_32_keys[i]); @@ -347,7 +347,6 @@ static int add_new_master_key(struct fscrypt_master_key_secret *secret, mk->mk_spec = *mk_spec; move_master_key_secret(&mk->mk_secret, secret); - init_rwsem(&mk->mk_secret_sem); refcount_set(&mk->mk_refcount, 1); /* secret is present */ INIT_LIST_HEAD(&mk->mk_decrypted_inodes); @@ -427,11 +426,8 @@ static int add_existing_master_key(struct fscrypt_master_key *mk, } /* Re-add the secret if needed. */ - if (rekey) { - down_write(&mk->mk_secret_sem); + if (rekey) move_master_key_secret(&mk->mk_secret, secret); - up_write(&mk->mk_secret_sem); - } return 0; } @@ -975,10 +971,8 @@ static int do_remove_key(struct file *filp, void __user *_uarg, bool all_users) /* No user claims remaining. Go ahead and wipe the secret. */ dead = false; if (is_master_key_secret_present(&mk->mk_secret)) { - down_write(&mk->mk_secret_sem); wipe_master_key_secret(&mk->mk_secret); dead = refcount_dec_and_test(&mk->mk_refcount); - up_write(&mk->mk_secret_sem); } up_write(&key->sem); if (dead) { diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index d595abb8ef90..261293fb7097 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -56,6 +56,8 @@ static struct fscrypt_mode * select_encryption_mode(const union fscrypt_policy *policy, const struct inode *inode) { + BUILD_BUG_ON(ARRAY_SIZE(fscrypt_modes) != FSCRYPT_MODE_MAX + 1); + if (S_ISREG(inode->i_mode)) return &fscrypt_modes[fscrypt_policy_contents_mode(policy)]; @@ -168,7 +170,7 @@ static int setup_per_mode_enc_key(struct fscrypt_info *ci, unsigned int hkdf_infolen = 0; int err; - if (WARN_ON(mode_num > __FSCRYPT_MODE_MAX)) + if (WARN_ON(mode_num > FSCRYPT_MODE_MAX)) return -EINVAL; prep_key = &keys[mode_num]; @@ -335,11 +337,11 @@ static int fscrypt_setup_v2_file_key(struct fscrypt_info *ci, * Find the master key, then set up the inode's actual encryption key. * * If the master key is found in the filesystem-level keyring, then the - * corresponding 'struct key' is returned in *master_key_ret with - * ->mk_secret_sem read-locked. This is needed to ensure that only one task - * links the fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race - * to create an fscrypt_info for the same inode), and to synchronize the master - * key being removed with a new inode starting to use it. + * corresponding 'struct key' is returned in *master_key_ret with its semaphore + * read-locked. This is needed to ensure that only one task links the + * fscrypt_info into ->mk_decrypted_inodes (as multiple tasks may race to create + * an fscrypt_info for the same inode), and to synchronize the master key being + * removed with a new inode starting to use it. */ static int setup_file_encryption_key(struct fscrypt_info *ci, bool need_dirhash_key, @@ -388,7 +390,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, } mk = key->payload.data[0]; - down_read(&mk->mk_secret_sem); + down_read(&key->sem); /* Has the secret been removed (via FS_IOC_REMOVE_ENCRYPTION_KEY)? */ if (!is_master_key_secret_present(&mk->mk_secret)) { @@ -431,7 +433,7 @@ static int setup_file_encryption_key(struct fscrypt_info *ci, return 0; out_release_key: - up_read(&mk->mk_secret_sem); + up_read(&key->sem); key_put(key); return err; } @@ -534,9 +536,7 @@ fscrypt_setup_encryption_info(struct inode *inode, res = 0; out: if (master_key) { - struct fscrypt_master_key *mk = master_key->payload.data[0]; - - up_read(&mk->mk_secret_sem); + up_read(&master_key->sem); key_put(master_key); } put_crypt_info(crypt_info); @@ -546,6 +546,11 @@ out: /** * fscrypt_get_encryption_info() - set up an inode's encryption key * @inode: the inode to set up the key for. Must be encrypted. + * @allow_unsupported: if %true, treat an unsupported encryption policy (or + * unrecognized encryption context) the same way as the key + * being unavailable, instead of returning an error. Use + * %false unless the operation being performed is needed in + * order for files (or directories) to be deleted. * * Set up ->i_crypt_info, if it hasn't already been done. * @@ -556,7 +561,7 @@ out: * encryption key is unavailable. (Use fscrypt_has_encryption_key() to * distinguish these cases.) Also can return another -errno code. */ -int fscrypt_get_encryption_info(struct inode *inode) +int fscrypt_get_encryption_info(struct inode *inode, bool allow_unsupported) { int res; union fscrypt_context ctx; @@ -567,29 +572,38 @@ int fscrypt_get_encryption_info(struct inode *inode) res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx)); if (res < 0) { + if (res == -ERANGE && allow_unsupported) + return 0; fscrypt_warn(inode, "Error %d getting encryption context", res); return res; } res = fscrypt_policy_from_context(&policy, &ctx, res); if (res) { + if (allow_unsupported) + return 0; fscrypt_warn(inode, "Unrecognized or corrupt encryption context"); return res; } - if (!fscrypt_supported_policy(&policy, inode)) + if (!fscrypt_supported_policy(&policy, inode)) { + if (allow_unsupported) + return 0; return -EINVAL; + } res = fscrypt_setup_encryption_info(inode, &policy, fscrypt_context_nonce(&ctx), IS_CASEFOLDED(inode) && S_ISDIR(inode->i_mode)); + + if (res == -ENOPKG && allow_unsupported) /* Algorithm unavailable? */ + res = 0; if (res == -ENOKEY) res = 0; return res; } -EXPORT_SYMBOL(fscrypt_get_encryption_info); /** * fscrypt_prepare_new_inode() - prepare to create a new inode in a directory @@ -710,7 +724,7 @@ int fscrypt_drop_inode(struct inode *inode) return 0; /* - * Note: since we aren't holding ->mk_secret_sem, the result here can + * Note: since we aren't holding the key semaphore, the result here can * immediately become outdated. But there's no correctness problem with * unnecessarily evicting. Nor is there a correctness problem with not * evicting while iput() is racing with the key being removed, since diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c index 4441d9944b9e..a51cef6bd27f 100644 --- a/fs/crypto/policy.c +++ b/fs/crypto/policy.c @@ -175,7 +175,10 @@ static bool fscrypt_supported_v2_policy(const struct fscrypt_policy_v2 *policy, return false; } - if (policy->flags & ~FSCRYPT_POLICY_FLAGS_VALID) { + if (policy->flags & ~(FSCRYPT_POLICY_FLAGS_PAD_MASK | + FSCRYPT_POLICY_FLAG_DIRECT_KEY | + FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 | + FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32)) { fscrypt_warn(inode, "Unsupported encryption flags (0x%02x)", policy->flags); return false; @@ -587,7 +590,7 @@ EXPORT_SYMBOL_GPL(fscrypt_ioctl_get_nonce); int fscrypt_has_permitted_context(struct inode *parent, struct inode *child) { union fscrypt_policy parent_policy, child_policy; - int err; + int err, err1, err2; /* No restrictions on file types which are never encrypted */ if (!S_ISREG(child->i_mode) && !S_ISDIR(child->i_mode) && @@ -617,19 +620,25 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child) * In any case, if an unexpected error occurs, fall back to "forbidden". */ - err = fscrypt_get_encryption_info(parent); + err = fscrypt_get_encryption_info(parent, true); if (err) return 0; - err = fscrypt_get_encryption_info(child); + err = fscrypt_get_encryption_info(child, true); if (err) return 0; - err = fscrypt_get_policy(parent, &parent_policy); - if (err) - return 0; + err1 = fscrypt_get_policy(parent, &parent_policy); + err2 = fscrypt_get_policy(child, &child_policy); - err = fscrypt_get_policy(child, &child_policy); - if (err) + /* + * Allow the case where the parent and child both have an unrecognized + * encryption policy, so that files with an unrecognized encryption + * policy can be deleted. + */ + if (err1 == -EINVAL && err2 == -EINVAL) + return 1; + + if (err1 || err2) return 0; return fscrypt_policies_equal(&parent_policy, &child_policy); diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index ca50c90adc4c..c6d16353326a 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -118,11 +118,9 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx) struct buffer_head *bh = NULL; struct fscrypt_str fstr = FSTR_INIT(NULL, 0); - if (IS_ENCRYPTED(inode)) { - err = fscrypt_get_encryption_info(inode); - if (err) - return err; - } + err = fscrypt_prepare_readdir(inode); + if (err) + return err; if (is_dx_dir(inode)) { err = ext4_dx_readdir(file, ctx); @@ -616,13 +614,6 @@ finished: return 0; } -static int ext4_dir_open(struct inode * inode, struct file * filp) -{ - if (IS_ENCRYPTED(inode)) - return fscrypt_get_encryption_info(inode) ? -EACCES : 0; - return 0; -} - static int ext4_release_dir(struct inode *inode, struct file *filp) { if (filp->private_data) @@ -664,7 +655,6 @@ const struct file_operations ext4_dir_operations = { .compat_ioctl = ext4_compat_ioctl, #endif .fsync = ext4_sync_file, - .open = ext4_dir_open, .release = ext4_release_dir, }; diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 33509266f5a0..5fa8436cd5fa 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -643,13 +643,7 @@ static struct stats dx_show_leaf(struct inode *dir, name = de->name; len = de->name_len; - if (IS_ENCRYPTED(dir)) - res = fscrypt_get_encryption_info(dir); - if (res) { - printk(KERN_WARNING "Error setting up" - " fname crypto: %d\n", res); - } - if (!fscrypt_has_encryption_key(dir)) { + if (!IS_ENCRYPTED(dir)) { /* Directory is not encrypted */ ext4fs_dirhash(dir, de->name, de->name_len, &h); @@ -1010,7 +1004,7 @@ static int htree_dirblock_to_tree(struct file *dir_file, EXT4_DIR_REC_LEN(0)); /* Check if the directory is encrypted */ if (IS_ENCRYPTED(dir)) { - err = fscrypt_get_encryption_info(dir); + err = fscrypt_prepare_readdir(dir); if (err < 0) { brelse(bh); return err; @@ -2195,6 +2189,9 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry, if (!dentry->d_name.len) return -EINVAL; + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; + #ifdef CONFIG_UNICODE if (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) && sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name)) diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c index 4b9ef8bbfa4a..049500f1e764 100644 --- a/fs/f2fs/dir.c +++ b/fs/f2fs/dir.c @@ -1022,7 +1022,7 @@ static int f2fs_readdir(struct file *file, struct dir_context *ctx) int err = 0; if (IS_ENCRYPTED(inode)) { - err = fscrypt_get_encryption_info(inode); + err = fscrypt_prepare_readdir(inode); if (err) goto out; @@ -1081,19 +1081,11 @@ out: return err < 0 ? err : 0; } -static int f2fs_dir_open(struct inode *inode, struct file *filp) -{ - if (IS_ENCRYPTED(inode)) - return fscrypt_get_encryption_info(inode) ? -EACCES : 0; - return 0; -} - const struct file_operations f2fs_dir_operations = { .llseek = generic_file_llseek, .read = generic_read_dir, .iterate_shared = f2fs_readdir, .fsync = f2fs_sync_file, - .open = f2fs_dir_open, .unlocked_ioctl = f2fs_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = f2fs_compat_ioctl, diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index cb700d797296..9a321c52face 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -3251,6 +3251,8 @@ bool f2fs_empty_dir(struct inode *dir); static inline int f2fs_add_link(struct dentry *dentry, struct inode *inode) { + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; return f2fs_do_add_link(d_inode(dentry->d_parent), &dentry->d_name, inode, inode->i_ino, inode->i_mode); } diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 155521e51ac5..1f33a5598b93 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -270,6 +270,15 @@ done: return d_splice_alias(inode, dentry); } +static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry, + struct fscrypt_name *nm) +{ + if (fscrypt_is_nokey_name(dentry)) + return -ENOKEY; + + return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm); +} + static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl) { @@ -293,7 +302,7 @@ static int ubifs_create(struct inode *dir, struct dentry *dentry, umode_t mode, if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -505,7 +514,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx) return 0; if (encrypted) { - err = fscrypt_get_encryption_info(dir); + err = fscrypt_prepare_readdir(dir); if (err) return err; @@ -953,7 +962,7 @@ static int ubifs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -1038,7 +1047,7 @@ static int ubifs_mknod(struct inode *dir, struct dentry *dentry, return err; } - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) { kfree(dev); goto out_budg; @@ -1122,7 +1131,7 @@ static int ubifs_symlink(struct inode *dir, struct dentry *dentry, if (err) return err; - err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm); + err = ubifs_prepare_create(dir, dentry, &nm); if (err) goto out_budg; @@ -1610,14 +1619,6 @@ int ubifs_getattr(const struct path *path, struct kstat *stat, return 0; } -static int ubifs_dir_open(struct inode *dir, struct file *file) -{ - if (IS_ENCRYPTED(dir)) - return fscrypt_get_encryption_info(dir) ? -EACCES : 0; - - return 0; -} - const struct inode_operations ubifs_dir_inode_operations = { .lookup = ubifs_lookup, .create = ubifs_create, @@ -1644,7 +1645,6 @@ const struct file_operations ubifs_dir_operations = { .iterate_shared = ubifs_readdir, .fsync = ubifs_fsync, .unlocked_ioctl = ubifs_ioctl, - .open = ubifs_dir_open, #ifdef CONFIG_COMPAT .compat_ioctl = ubifs_compat_ioctl, #endif diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index a8f7a43f031b..d23156d1ac94 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -75,7 +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. @@ -111,6 +111,35 @@ 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 *); @@ -171,7 +200,6 @@ 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); @@ -213,6 +241,8 @@ 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, const char *target, @@ -244,6 +274,11 @@ 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) { @@ -372,10 +407,6 @@ 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, @@ -503,6 +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) @@ -642,32 +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 @@ -676,8 +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. @@ -738,8 +753,9 @@ 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. @@ -763,6 +779,26 @@ 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 @@ -783,8 +819,8 @@ 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; } diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h index e5de60336938..9f4428be3e36 100644 --- a/include/uapi/linux/fscrypt.h +++ b/include/uapi/linux/fscrypt.h @@ -20,7 +20,6 @@ #define FSCRYPT_POLICY_FLAG_DIRECT_KEY 0x04 #define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 0x08 #define FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32 0x10 -#define FSCRYPT_POLICY_FLAGS_VALID 0x1F /* Encryption algorithms */ #define FSCRYPT_MODE_AES_256_XTS 1 @@ -28,7 +27,7 @@ #define FSCRYPT_MODE_AES_128_CBC 5 #define FSCRYPT_MODE_AES_128_CTS 6 #define FSCRYPT_MODE_ADIANTUM 9 -#define __FSCRYPT_MODE_MAX 9 +/* If adding a mode number > 9, update FSCRYPT_MODE_MAX in fscrypt_private.h */ /* * Legacy policy version; ad-hoc KDF and no key verification. @@ -177,7 +176,7 @@ struct fscrypt_get_key_status_arg { #define FS_POLICY_FLAGS_PAD_32 FSCRYPT_POLICY_FLAGS_PAD_32 #define FS_POLICY_FLAGS_PAD_MASK FSCRYPT_POLICY_FLAGS_PAD_MASK #define FS_POLICY_FLAG_DIRECT_KEY FSCRYPT_POLICY_FLAG_DIRECT_KEY -#define FS_POLICY_FLAGS_VALID FSCRYPT_POLICY_FLAGS_VALID +#define FS_POLICY_FLAGS_VALID 0x07 /* contains old flags only */ #define FS_ENCRYPTION_MODE_INVALID 0 /* never used */ #define FS_ENCRYPTION_MODE_AES_256_XTS FSCRYPT_MODE_AES_256_XTS #define FS_ENCRYPTION_MODE_AES_256_GCM 2 /* never used */ |