From patchwork Mon Aug 5 16:25:10 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 1142348 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.infradead.org (client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="hMnLHvMU"; dkim=fail reason="signature verification failed" (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="Bg347hDr"; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 462Ndd5r3Jz9s7T for ; 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Mon, 05 Aug 2019 16:34:27 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hufqf-0008Or-Nq for linux-mtd@lists.infradead.org; Mon, 05 Aug 2019 16:28:48 +0000 Received: from ebiggers-linuxstation.mtv.corp.google.com (unknown [104.132.1.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 71BEC21871; Mon, 5 Aug 2019 16:28:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565022514; bh=5tq212H09/beu3ZmJb2d6tVxNKTCnLAppoBl2mPFLyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Bg347hDrp02Qrk9rcLoFSvSkdqpPjCK8POkjWFkwYrYfJsxda4SOnUYlQMslHN2Er epAzDyuM50uqSeSRYc0W8VeuE2PvEv1l98lWndFmKzQHYxyNhm4eak/JAC2SW3fB6L y2oMaBFs6L0I/Ci4DKPr8or4i2vfOhIcgeWGqASE= From: Eric Biggers To: linux-fscrypt@vger.kernel.org Subject: [PATCH v8 09/20] fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl Date: Mon, 5 Aug 2019 09:25:10 -0700 Message-Id: <20190805162521.90882-10-ebiggers@kernel.org> X-Mailer: git-send-email 2.22.0.770.g0f2c4a37fd-goog In-Reply-To: <20190805162521.90882-1-ebiggers@kernel.org> References: <20190805162521.90882-1-ebiggers@kernel.org> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190805_092838_002109_95AAFD3F X-CRM114-Status: GOOD ( 30.58 ) X-Spam-Score: -5.2 (-----) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-5.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -5.0 RCVD_IN_DNSWL_HI RBL: Sender listed at https://www.dnswl.org/, high trust [198.145.29.99 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.0 DKIMWL_WL_HIGH DKIMwl.org - Whitelisted High sender X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Satya Tangirala , Theodore Ts'o , linux-api@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, keyrings@vger.kernel.org, linux-mtd@lists.infradead.org, linux-crypto@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jaegeuk Kim , linux-ext4@vger.kernel.org, Paul Crowley Sender: "linux-mtd" Errors-To: linux-mtd-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org From: Eric Biggers Add a new fscrypt ioctl, FS_IOC_ADD_ENCRYPTION_KEY. This ioctl adds an encryption key to the filesystem's fscrypt keyring ->s_master_keys, making any files encrypted with that key appear "unlocked". Why we need this ~~~~~~~~~~~~~~~~ The main problem is that the "locked/unlocked" (ciphertext/plaintext) status of encrypted files is global, but the fscrypt keys are not. fscrypt only looks for keys in the keyring(s) the process accessing the filesystem is subscribed to: the thread keyring, process keyring, and session keyring, where the session keyring may contain the user keyring. Therefore, userspace has to put fscrypt keys in the keyrings for individual users or sessions. But this means that when a process with a different keyring tries to access encrypted files, whether they appear "unlocked" or not is nondeterministic. This is because it depends on whether the files are currently present in the inode cache. Fixing this by consistently providing each process its own view of the filesystem depending on whether it has the key or not isn't feasible due to how the VFS caches work. Furthermore, while sometimes users expect this behavior, it is misguided for two reasons. First, it would be an OS-level access control mechanism largely redundant with existing access control mechanisms such as UNIX file permissions, ACLs, LSMs, etc. Encryption is actually for protecting the data at rest. Second, almost all users of fscrypt actually do need the keys to be global. The largest users of fscrypt, Android and Chromium OS, achieve this by having PID 1 create a "session keyring" that is inherited by every process. This works, but it isn't scalable because it prevents session keyrings from being used for any other purpose. On general-purpose Linux distros, the 'fscrypt' userspace tool [1] can't similarly abuse the session keyring, so to make 'sudo' work on all systems it has to link all the user keyrings into root's user keyring [2]. This is ugly and raises security concerns. Moreover it can't make the keys available to system services, such as sshd trying to access the user's '~/.ssh' directory (see [3], [4]) or NetworkManager trying to read certificates from the user's home directory (see [5]); or to Docker containers (see [6], [7]). By having an API to add a key to the *filesystem* we'll be able to fix the above bugs, remove userspace workarounds, and clearly express the intended semantics: the locked/unlocked status of an encrypted directory is global, and encryption is orthogonal to OS-level access control. Why not use the add_key() syscall ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We use an ioctl for this API rather than the existing add_key() system call because the ioctl gives us the flexibility needed to implement fscrypt-specific semantics that will be introduced in later patches: - Supporting key removal with the semantics such that the secret is removed immediately and any unused inodes using the key are evicted; also, the eviction of any in-use inodes can be retried. - Calculating a key-dependent cryptographic identifier and returning it to userspace. - Allowing keys to be added and removed by non-root users, but only keys for v2 encryption policies; and to prevent denial-of-service attacks, users can only remove keys they themselves have added, and a key is only really removed after all users who added it have removed it. Trying to shoehorn these semantics into the keyrings syscalls would be very difficult, whereas the ioctls make things much easier. However, to reuse code the implementation still uses the keyrings service internally. Thus we get lockless RCU-mode key lookups without having to re-implement it, and the keys automatically show up in /proc/keys for debugging purposes. References: [1] https://github.com/google/fscrypt [2] https://goo.gl/55cCrI#heading=h.vf09isp98isb [3] https://github.com/google/fscrypt/issues/111#issuecomment-444347939 [4] https://github.com/google/fscrypt/issues/116 [5] https://bugs.launchpad.net/ubuntu/+source/fscrypt/+bug/1770715 [6] https://github.com/google/fscrypt/issues/128 [7] https://askubuntu.com/questions/1130306/cannot-run-docker-on-an-encrypted-filesystem Reviewed-by: Theodore Ts'o Signed-off-by: Eric Biggers --- fs/crypto/Makefile | 1 + fs/crypto/crypto.c | 10 +- fs/crypto/fscrypt_private.h | 62 +++++++- fs/crypto/keyring.c | 286 +++++++++++++++++++++++++++++++++++ fs/crypto/keysetup.c | 35 ++++- fs/super.c | 2 + include/linux/fs.h | 1 + include/linux/fscrypt.h | 14 ++ include/uapi/linux/fscrypt.h | 49 ++++-- 9 files changed, 447 insertions(+), 13 deletions(-) create mode 100644 fs/crypto/keyring.c diff --git a/fs/crypto/Makefile b/fs/crypto/Makefile index ad14d4c29784a6..6b2485b4139335 100644 --- a/fs/crypto/Makefile +++ b/fs/crypto/Makefile @@ -4,6 +4,7 @@ obj-$(CONFIG_FS_ENCRYPTION) += fscrypto.o fscrypto-y := crypto.o \ fname.o \ hooks.o \ + keyring.o \ keysetup.o \ keysetup_v1.o \ policy.o diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c index 7502c1f0ede9e9..65ca077e8d585f 100644 --- a/fs/crypto/crypto.c +++ b/fs/crypto/crypto.c @@ -478,6 +478,8 @@ void fscrypt_msg(const struct inode *inode, const char *level, */ static int __init fscrypt_init(void) { + int err = -ENOMEM; + /* * Use an unbound workqueue to allow bios to be decrypted in parallel * even when they happen to complete on the same CPU. This sacrifices @@ -500,13 +502,19 @@ static int __init fscrypt_init(void) if (!fscrypt_info_cachep) goto fail_free_ctx; + err = fscrypt_init_keyring(); + if (err) + goto fail_free_info; + return 0; +fail_free_info: + kmem_cache_destroy(fscrypt_info_cachep); fail_free_ctx: kmem_cache_destroy(fscrypt_ctx_cachep); fail_free_queue: destroy_workqueue(fscrypt_read_workqueue); fail: - return -ENOMEM; + return err; } late_initcall(fscrypt_init) diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 794dcba25ca826..0d9ebfd3bf3a54 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -14,9 +14,12 @@ #include #include -/* Encryption parameters */ +#define CONST_STRLEN(str) (sizeof(str) - 1) + #define FS_KEY_DERIVATION_NONCE_SIZE 16 +#define FSCRYPT_MIN_KEY_SIZE 16 + /** * Encryption context for inode * @@ -156,6 +159,63 @@ extern bool fscrypt_fname_encrypted_size(const struct inode *inode, u32 orig_len, u32 max_len, u32 *encrypted_len_ret); +/* keyring.c */ + +/* + * fscrypt_master_key_secret - secret key material of an in-use master key + */ +struct fscrypt_master_key_secret { + + /* Size of the raw key in bytes */ + u32 size; + + /* The raw key */ + u8 raw[FSCRYPT_MAX_KEY_SIZE]; + +} __randomize_layout; + +/* + * fscrypt_master_key - an in-use master key + * + * This represents a master encryption key which has been added to the + * filesystem and can be used to "unlock" the encrypted files which were + * encrypted with it. + */ +struct fscrypt_master_key { + + /* The secret key material */ + struct fscrypt_master_key_secret mk_secret; + + /* Arbitrary key descriptor which was assigned by userspace */ + struct fscrypt_key_specifier mk_spec; + +} __randomize_layout; + +static inline const char *master_key_spec_type( + const struct fscrypt_key_specifier *spec) +{ + switch (spec->type) { + case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR: + return "descriptor"; + } + return "[unknown]"; +} + +static inline int master_key_spec_len(const struct fscrypt_key_specifier *spec) +{ + switch (spec->type) { + case FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR: + return FSCRYPT_KEY_DESCRIPTOR_SIZE; + } + return 0; +} + +extern struct key * +fscrypt_find_master_key(struct super_block *sb, + const struct fscrypt_key_specifier *mk_spec); + +extern int __init fscrypt_init_keyring(void); + /* keysetup.c */ struct fscrypt_mode { diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c new file mode 100644 index 00000000000000..bcd7d2836e1e4c --- /dev/null +++ b/fs/crypto/keyring.c @@ -0,0 +1,286 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Filesystem-level keyring for fscrypt + * + * Copyright 2019 Google LLC + */ + +/* + * This file implements management of fscrypt master keys in the + * filesystem-level keyring, including the ioctls: + * + * - FS_IOC_ADD_ENCRYPTION_KEY + * + * See the "User API" section of Documentation/filesystems/fscrypt.rst for more + * information about these ioctls. + */ + +#include +#include + +#include "fscrypt_private.h" + +static void wipe_master_key_secret(struct fscrypt_master_key_secret *secret) +{ + memzero_explicit(secret, sizeof(*secret)); +} + +static void move_master_key_secret(struct fscrypt_master_key_secret *dst, + struct fscrypt_master_key_secret *src) +{ + memcpy(dst, src, sizeof(*dst)); + memzero_explicit(src, sizeof(*src)); +} + +static void free_master_key(struct fscrypt_master_key *mk) +{ + wipe_master_key_secret(&mk->mk_secret); + kzfree(mk); +} + +static inline bool valid_key_spec(const struct fscrypt_key_specifier *spec) +{ + if (spec->__reserved) + return false; + return master_key_spec_len(spec) != 0; +} + +static int fscrypt_key_instantiate(struct key *key, + struct key_preparsed_payload *prep) +{ + key->payload.data[0] = (struct fscrypt_master_key *)prep->data; + return 0; +} + +static void fscrypt_key_destroy(struct key *key) +{ + free_master_key(key->payload.data[0]); +} + +static void fscrypt_key_describe(const struct key *key, struct seq_file *m) +{ + seq_puts(m, key->description); +} + +/* + * Type of key in ->s_master_keys. Each key of this type represents a master + * key which has been added to the filesystem. Its payload is a + * 'struct fscrypt_master_key'. The "." prefix in the key type name prevents + * users from adding keys of this type via the keyrings syscalls rather than via + * the intended method of FS_IOC_ADD_ENCRYPTION_KEY. + */ +static struct key_type key_type_fscrypt = { + .name = "._fscrypt", + .instantiate = fscrypt_key_instantiate, + .destroy = fscrypt_key_destroy, + .describe = fscrypt_key_describe, +}; + +/* Search ->s_master_keys */ +static struct key *search_fscrypt_keyring(struct key *keyring, + struct key_type *type, + const char *description) +{ + /* + * We need to mark the keyring reference as "possessed" so that we + * acquire permission to search it, via the KEY_POS_SEARCH permission. + */ + key_ref_t keyref = make_key_ref(keyring, true /* possessed */); + + keyref = keyring_search(keyref, type, description, false); + if (IS_ERR(keyref)) { + if (PTR_ERR(keyref) == -EAGAIN || /* not found */ + PTR_ERR(keyref) == -EKEYREVOKED) /* recently invalidated */ + keyref = ERR_PTR(-ENOKEY); + return ERR_CAST(keyref); + } + return key_ref_to_ptr(keyref); +} + +#define FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE \ + (CONST_STRLEN("fscrypt-") + FIELD_SIZEOF(struct super_block, s_id)) + +#define FSCRYPT_MK_DESCRIPTION_SIZE (2 * FSCRYPT_KEY_DESCRIPTOR_SIZE + 1) + +static void format_fs_keyring_description( + char description[FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE], + const struct super_block *sb) +{ + sprintf(description, "fscrypt-%s", sb->s_id); +} + +static void format_mk_description( + char description[FSCRYPT_MK_DESCRIPTION_SIZE], + const struct fscrypt_key_specifier *mk_spec) +{ + sprintf(description, "%*phN", + master_key_spec_len(mk_spec), (u8 *)&mk_spec->u); +} + +/* Create ->s_master_keys if needed. Synchronized by fscrypt_add_key_mutex. */ +static int allocate_filesystem_keyring(struct super_block *sb) +{ + char description[FSCRYPT_FS_KEYRING_DESCRIPTION_SIZE]; + struct key *keyring; + + if (sb->s_master_keys) + return 0; + + format_fs_keyring_description(description, sb); + keyring = keyring_alloc(description, GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, + current_cred(), KEY_POS_SEARCH | + KEY_USR_SEARCH | KEY_USR_READ | KEY_USR_VIEW, + KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL); + if (IS_ERR(keyring)) + return PTR_ERR(keyring); + + /* Pairs with READ_ONCE() in fscrypt_find_master_key() */ + smp_store_release(&sb->s_master_keys, keyring); + return 0; +} + +void fscrypt_sb_free(struct super_block *sb) +{ + key_put(sb->s_master_keys); + sb->s_master_keys = NULL; +} + +/* + * Find the specified master key in ->s_master_keys. + * Returns ERR_PTR(-ENOKEY) if not found. + */ +struct key *fscrypt_find_master_key(struct super_block *sb, + const struct fscrypt_key_specifier *mk_spec) +{ + struct key *keyring; + char description[FSCRYPT_MK_DESCRIPTION_SIZE]; + + /* pairs with smp_store_release() in allocate_filesystem_keyring() */ + keyring = READ_ONCE(sb->s_master_keys); + if (keyring == NULL) + return ERR_PTR(-ENOKEY); /* No keyring yet, so no keys yet. */ + + format_mk_description(description, mk_spec); + return search_fscrypt_keyring(keyring, &key_type_fscrypt, description); +} + +/* + * Allocate a new fscrypt_master_key which contains the given secret, set it as + * the payload of a new 'struct key' of type fscrypt, and link the 'struct key' + * into the given keyring. Synchronized by fscrypt_add_key_mutex. + */ +static int add_new_master_key(struct fscrypt_master_key_secret *secret, + const struct fscrypt_key_specifier *mk_spec, + struct key *keyring) +{ + struct fscrypt_master_key *mk; + char description[FSCRYPT_MK_DESCRIPTION_SIZE]; + struct key *key; + int err; + + mk = kzalloc(sizeof(*mk), GFP_KERNEL); + if (!mk) + return -ENOMEM; + + mk->mk_spec = *mk_spec; + + move_master_key_secret(&mk->mk_secret, secret); + + format_mk_description(description, mk_spec); + key = key_alloc(&key_type_fscrypt, description, + GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), + KEY_POS_SEARCH | KEY_USR_SEARCH | KEY_USR_VIEW, + KEY_ALLOC_NOT_IN_QUOTA, NULL); + if (IS_ERR(key)) { + err = PTR_ERR(key); + goto out_free_mk; + } + err = key_instantiate_and_link(key, mk, sizeof(*mk), keyring, NULL); + key_put(key); + if (err) + goto out_free_mk; + + return 0; + +out_free_mk: + free_master_key(mk); + return err; +} + +static int add_master_key(struct super_block *sb, + struct fscrypt_master_key_secret *secret, + const struct fscrypt_key_specifier *mk_spec) +{ + static DEFINE_MUTEX(fscrypt_add_key_mutex); + struct key *key; + int err; + + mutex_lock(&fscrypt_add_key_mutex); /* serialize find + link */ + key = fscrypt_find_master_key(sb, mk_spec); + if (IS_ERR(key)) { + err = PTR_ERR(key); + if (err != -ENOKEY) + goto out_unlock; + /* Didn't find the key in ->s_master_keys. Add it. */ + err = allocate_filesystem_keyring(sb); + if (err) + goto out_unlock; + err = add_new_master_key(secret, mk_spec, sb->s_master_keys); + } else { + key_put(key); + err = 0; + } +out_unlock: + mutex_unlock(&fscrypt_add_key_mutex); + return err; +} + +/* + * Add a master encryption key to the filesystem, causing all files which were + * encrypted with it to appear "unlocked" (decrypted) when accessed. + * + * For more details, see the "FS_IOC_ADD_ENCRYPTION_KEY" section of + * Documentation/filesystems/fscrypt.rst. + */ +int fscrypt_ioctl_add_key(struct file *filp, void __user *_uarg) +{ + struct super_block *sb = file_inode(filp)->i_sb; + struct fscrypt_add_key_arg __user *uarg = _uarg; + struct fscrypt_add_key_arg arg; + struct fscrypt_master_key_secret secret; + int err; + + if (copy_from_user(&arg, uarg, sizeof(arg))) + return -EFAULT; + + if (!valid_key_spec(&arg.key_spec)) + return -EINVAL; + + if (arg.raw_size < FSCRYPT_MIN_KEY_SIZE || + arg.raw_size > FSCRYPT_MAX_KEY_SIZE) + return -EINVAL; + + if (memchr_inv(arg.__reserved, 0, sizeof(arg.__reserved))) + return -EINVAL; + + memset(&secret, 0, sizeof(secret)); + secret.size = arg.raw_size; + err = -EFAULT; + if (copy_from_user(secret.raw, uarg->raw, secret.size)) + goto out_wipe_secret; + + err = -EACCES; + if (!capable(CAP_SYS_ADMIN)) + goto out_wipe_secret; + + err = add_master_key(sb, &secret, &arg.key_spec); +out_wipe_secret: + wipe_master_key_secret(&secret); + return err; +} +EXPORT_SYMBOL_GPL(fscrypt_ioctl_add_key); + +int __init fscrypt_init_keyring(void) +{ + return register_key_type(&key_type_fscrypt); +} diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index f4a47448e9efa1..1c6d18bcdc7b64 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -216,7 +216,40 @@ int fscrypt_set_derived_key(struct fscrypt_info *ci, const u8 *derived_key) */ static int setup_file_encryption_key(struct fscrypt_info *ci) { - return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci); + struct key *key; + struct fscrypt_master_key *mk = NULL; + struct fscrypt_key_specifier mk_spec; + int err; + + mk_spec.type = FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR; + memcpy(mk_spec.u.descriptor, ci->ci_master_key_descriptor, + FSCRYPT_KEY_DESCRIPTOR_SIZE); + + key = fscrypt_find_master_key(ci->ci_inode->i_sb, &mk_spec); + if (IS_ERR(key)) { + if (key != ERR_PTR(-ENOKEY)) + return PTR_ERR(key); + + return fscrypt_setup_v1_file_key_via_subscribed_keyrings(ci); + } + + mk = key->payload.data[0]; + + if (mk->mk_secret.size < ci->ci_mode->keysize) { + fscrypt_warn(NULL, + "key with %s %*phN is too short (got %u bytes, need %u+ bytes)", + master_key_spec_type(&mk_spec), + master_key_spec_len(&mk_spec), (u8 *)&mk_spec.u, + mk->mk_secret.size, ci->ci_mode->keysize); + err = -ENOKEY; + goto out_release_key; + } + + err = fscrypt_setup_v1_file_key(ci, mk->mk_secret.raw); + +out_release_key: + key_put(key); + return err; } static void put_crypt_info(struct fscrypt_info *ci) diff --git a/fs/super.c b/fs/super.c index 5960578a40760a..e486a442a61fb2 100644 --- a/fs/super.c +++ b/fs/super.c @@ -32,6 +32,7 @@ #include #include #include +#include #include #include #include @@ -290,6 +291,7 @@ static void __put_super(struct super_block *s) WARN_ON(s->s_inode_lru.node); WARN_ON(!list_empty(&s->s_mounts)); security_sb_free(s); + fscrypt_sb_free(s); put_user_ns(s->s_user_ns); kfree(s->s_subtype); call_rcu(&s->rcu, destroy_super_rcu); diff --git a/include/linux/fs.h b/include/linux/fs.h index 997a530ff4e9d0..5dff77326cec60 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1427,6 +1427,7 @@ struct super_block { const struct xattr_handler **s_xattr; #ifdef CONFIG_FS_ENCRYPTION const struct fscrypt_operations *s_cop; + struct key *s_master_keys; /* master crypto keys in use */ #endif struct hlist_bl_head s_roots; /* alternate root dentries for NFS */ struct list_head s_mounts; /* list of mounts; _not_ for fs use */ diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 583802cb2e35d0..46bf66cf76ef88 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -138,6 +138,10 @@ extern int fscrypt_ioctl_get_policy(struct file *, void __user *); extern int fscrypt_has_permitted_context(struct inode *, struct inode *); extern int fscrypt_inherit_context(struct inode *, struct inode *, void *, bool); +/* keyring.c */ +extern void fscrypt_sb_free(struct super_block *sb); +extern int fscrypt_ioctl_add_key(struct file *filp, void __user *arg); + /* keysetup.c */ extern int fscrypt_get_encryption_info(struct inode *); extern void fscrypt_put_encryption_info(struct inode *); @@ -367,6 +371,16 @@ static inline int fscrypt_inherit_context(struct inode *parent, return -EOPNOTSUPP; } +/* keyring.c */ +static inline void fscrypt_sb_free(struct super_block *sb) +{ +} + +static inline int fscrypt_ioctl_add_key(struct file *filp, void __user *arg) +{ + return -EOPNOTSUPP; +} + /* keysetup.c */ static inline int fscrypt_get_encryption_info(struct inode *inode) { diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h index 29a945d165def3..6aeca3cb0a2dec 100644 --- a/include/uapi/linux/fscrypt.h +++ b/include/uapi/linux/fscrypt.h @@ -36,22 +36,51 @@ struct fscrypt_policy { __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; }; -#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy) -#define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16]) -#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy) - -/* Parameters for passing an encryption key into the kernel keyring */ +/* + * Process-subscribed "logon" key description prefix and payload format. + * Deprecated; prefer FS_IOC_ADD_ENCRYPTION_KEY instead. + */ #define FSCRYPT_KEY_DESC_PREFIX "fscrypt:" -#define FSCRYPT_KEY_DESC_PREFIX_SIZE 8 - -/* Structure that userspace passes to the kernel keyring */ -#define FSCRYPT_MAX_KEY_SIZE 64 - +#define FSCRYPT_KEY_DESC_PREFIX_SIZE 8 +#define FSCRYPT_MAX_KEY_SIZE 64 struct fscrypt_key { __u32 mode; __u8 raw[FSCRYPT_MAX_KEY_SIZE]; __u32 size; }; + +/* + * Keys are specified by an arbitrary 8-byte key "descriptor", + * matching fscrypt_policy::master_key_descriptor. + */ +#define FSCRYPT_KEY_SPEC_TYPE_DESCRIPTOR 1 + +/* + * Specifies a key. This doesn't contain the actual key itself; this is just + * the "name" of the key. + */ +struct fscrypt_key_specifier { + __u32 type; /* one of FSCRYPT_KEY_SPEC_TYPE_* */ + __u32 __reserved; + union { + __u8 __reserved[32]; /* reserve some extra space */ + __u8 descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE]; + } u; +}; + +/* Struct passed to FS_IOC_ADD_ENCRYPTION_KEY */ +struct fscrypt_add_key_arg { + struct fscrypt_key_specifier key_spec; + __u32 raw_size; + __u32 __reserved[9]; + __u8 raw[]; +}; + +#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy) +#define FS_IOC_GET_ENCRYPTION_PWSALT _IOW('f', 20, __u8[16]) +#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy) +#define FS_IOC_ADD_ENCRYPTION_KEY _IOWR('f', 23, struct fscrypt_add_key_arg) + /**********************************************************************/ /* old names; don't add anything new here! */