diff options
| -rw-r--r-- | fs/crypto/hooks.c | 40 | ||||
| -rw-r--r-- | fs/crypto/keyinfo.c | 21 | ||||
| -rw-r--r-- | fs/ext4/super.c | 3 | ||||
| -rw-r--r-- | fs/f2fs/super.c | 3 | ||||
| -rw-r--r-- | fs/ubifs/super.c | 3 | ||||
| -rw-r--r-- | include/linux/fscrypt.h | 5 |
6 files changed, 68 insertions, 7 deletions
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 042d5b44f4ed..2dc22549d724 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -189,11 +189,9 @@ int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, sd->len = cpu_to_le16(ciphertext_len); err = fname_encrypt(inode, &iname, sd->encrypted_path, ciphertext_len); - if (err) { - if (!disk_link->name) - kfree(sd); - return err; - } + if (err) + goto err_free_sd; + /* * Null-terminating the ciphertext doesn't make sense, but we still * count the null terminator in the length, so we might as well @@ -201,9 +199,20 @@ int __fscrypt_encrypt_symlink(struct inode *inode, const char *target, */ sd->encrypted_path[ciphertext_len] = '\0'; + /* Cache the plaintext symlink target for later use by get_link() */ + err = -ENOMEM; + inode->i_link = kmemdup(target, len + 1, GFP_NOFS); + if (!inode->i_link) + goto err_free_sd; + if (!disk_link->name) disk_link->name = (unsigned char *)sd; return 0; + +err_free_sd: + if (!disk_link->name) + kfree(sd); + return err; } EXPORT_SYMBOL_GPL(__fscrypt_encrypt_symlink); @@ -212,7 +221,7 @@ EXPORT_SYMBOL_GPL(__fscrypt_encrypt_symlink); * @inode: the symlink inode * @caddr: the on-disk contents of the symlink * @max_size: size of @caddr buffer - * @done: if successful, will be set up to free the returned target + * @done: if successful, will be set up to free the returned target if needed * * If the symlink's encryption key is available, we decrypt its target. * Otherwise, we encode its target for presentation. @@ -227,12 +236,18 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, { const struct fscrypt_symlink_data *sd; struct fscrypt_str cstr, pstr; + bool has_key; int err; /* This is for encrypted symlinks only */ if (WARN_ON(!IS_ENCRYPTED(inode))) return ERR_PTR(-EINVAL); + /* If the decrypted target is already cached, just return it. */ + pstr.name = READ_ONCE(inode->i_link); + if (pstr.name) + return pstr.name; + /* * Try to set up the symlink's encryption key, but we can continue * regardless of whether the key is available or not. @@ -240,6 +255,7 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, err = fscrypt_get_encryption_info(inode); if (err) return ERR_PTR(err); + has_key = fscrypt_has_encryption_key(inode); /* * For historical reasons, encrypted symlink targets are prefixed with @@ -271,7 +287,17 @@ const char *fscrypt_get_symlink(struct inode *inode, const void *caddr, goto err_kfree; pstr.name[pstr.len] = '\0'; - set_delayed_call(done, kfree_link, pstr.name); + + /* + * Cache decrypted symlink targets in i_link for later use. Don't cache + * symlink targets encoded without the key, since those become outdated + * once the key is added. This pairs with the READ_ONCE() above and in + * the VFS path lookup code. + */ + if (!has_key || + cmpxchg_release(&inode->i_link, NULL, pstr.name) != NULL) + set_delayed_call(done, kfree_link, pstr.name); + return pstr.name; err_kfree: diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c index bf291c10c682..82989098b2fc 100644 --- a/fs/crypto/keyinfo.c +++ b/fs/crypto/keyinfo.c @@ -584,9 +584,30 @@ out: } EXPORT_SYMBOL(fscrypt_get_encryption_info); +/** + * fscrypt_put_encryption_info - free most of an inode's fscrypt data + * + * Free the inode's fscrypt_info. Filesystems must call this when the inode is + * being evicted. An RCU grace period need not have elapsed yet. + */ void fscrypt_put_encryption_info(struct inode *inode) { put_crypt_info(inode->i_crypt_info); inode->i_crypt_info = NULL; } EXPORT_SYMBOL(fscrypt_put_encryption_info); + +/** + * fscrypt_free_inode - free an inode's fscrypt data requiring RCU delay + * + * Free the inode's cached decrypted symlink target, if any. Filesystems must + * call this after an RCU grace period, just before they free the inode. + */ +void fscrypt_free_inode(struct inode *inode) +{ + if (IS_ENCRYPTED(inode) && S_ISLNK(inode->i_mode)) { + kfree(inode->i_link); + inode->i_link = NULL; + } +} +EXPORT_SYMBOL(fscrypt_free_inode); diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 6ed4eb81e674..5b92054bf8ea 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1110,6 +1110,9 @@ static int ext4_drop_inode(struct inode *inode) static void ext4_i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); + + fscrypt_free_inode(inode); + kmem_cache_free(ext4_inode_cachep, EXT4_I(inode)); } diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index f2aaa2cc6b3e..11b3a039a188 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -1003,6 +1003,9 @@ static void f2fs_dirty_inode(struct inode *inode, int flags) static void f2fs_i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); + + fscrypt_free_inode(inode); + kmem_cache_free(f2fs_inode_cachep, F2FS_I(inode)); } diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c index 12628184772c..19fd21098745 100644 --- a/fs/ubifs/super.c +++ b/fs/ubifs/super.c @@ -276,7 +276,10 @@ static void ubifs_i_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); struct ubifs_inode *ui = ubifs_inode(inode); + kfree(ui->data); + fscrypt_free_inode(inode); + kmem_cache_free(ubifs_inode_slab, ui); } diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index abe7081b6b22..28c74e0a7231 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -128,6 +128,7 @@ extern int fscrypt_inherit_context(struct inode *, struct inode *, /* keyinfo.c */ extern int fscrypt_get_encryption_info(struct inode *); extern void fscrypt_put_encryption_info(struct inode *); +extern void fscrypt_free_inode(struct inode *); /* fname.c */ extern int fscrypt_setup_filename(struct inode *, const struct qstr *, @@ -341,6 +342,10 @@ static inline void fscrypt_put_encryption_info(struct inode *inode) return; } +static inline void fscrypt_free_inode(struct inode *inode) +{ +} + /* fname.c */ static inline int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname, |