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authorLinus Torvalds <torvalds@linux-foundation.org>2017-11-14 11:35:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-14 11:35:15 -0800
commit32190f0afbf4f1c0a9142e5a886a078ee0b794fd (patch)
tree865f5cd7effacf40c02e7cda5c31fef8a0624c89
parent37dc79565c4b7e735f190eaa6ed5bb6eb3d3968a (diff)
parenta0b3bc855374c50b5ea85273553485af48caf2f7 (diff)
downloadlinux-32190f0afbf4f1c0a9142e5a886a078ee0b794fd.tar.bz2
Merge tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt
Pull fscrypt updates from Ted Ts'o: "Lots of cleanups, mostly courtesy by Eric Biggers" * tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt: fscrypt: lock mutex before checking for bounce page pool fscrypt: add a documentation file for filesystem-level encryption ext4: switch to fscrypt_prepare_setattr() ext4: switch to fscrypt_prepare_lookup() ext4: switch to fscrypt_prepare_rename() ext4: switch to fscrypt_prepare_link() ext4: switch to fscrypt_file_open() fscrypt: new helper function - fscrypt_prepare_setattr() fscrypt: new helper function - fscrypt_prepare_lookup() fscrypt: new helper function - fscrypt_prepare_rename() fscrypt: new helper function - fscrypt_prepare_link() fscrypt: new helper function - fscrypt_file_open() fscrypt: new helper function - fscrypt_require_key() fscrypt: remove unneeded empty fscrypt_operations structs fscrypt: remove ->is_encrypted() fscrypt: switch from ->is_encrypted() to IS_ENCRYPTED() fs, fscrypt: add an S_ENCRYPTED inode flag fscrypt: clean up include file mess
-rw-r--r--Documentation/filesystems/fscrypt.rst610
-rw-r--r--Documentation/filesystems/index.rst11
-rw-r--r--MAINTAINERS1
-rw-r--r--fs/crypto/Makefile2
-rw-r--r--fs/crypto/crypto.c9
-rw-r--r--fs/crypto/fname.c3
-rw-r--r--fs/crypto/fscrypt_private.h3
-rw-r--r--fs/crypto/hooks.c112
-rw-r--r--fs/crypto/keyinfo.c2
-rw-r--r--fs/crypto/policy.c6
-rw-r--r--fs/ext4/ext4.h8
-rw-r--r--fs/ext4/file.c23
-rw-r--r--fs/ext4/inode.c19
-rw-r--r--fs/ext4/namei.c62
-rw-r--r--fs/ext4/super.c15
-rw-r--r--fs/f2fs/f2fs.h9
-rw-r--r--fs/f2fs/inode.c5
-rw-r--r--fs/f2fs/super.c7
-rw-r--r--fs/ubifs/crypto.c1
-rw-r--r--fs/ubifs/ioctl.c5
-rw-r--r--fs/ubifs/super.c8
-rw-r--r--fs/ubifs/ubifs.h18
-rw-r--r--fs/ubifs/xattr.c1
-rw-r--r--include/linux/fs.h2
-rw-r--r--include/linux/fscrypt.h294
-rw-r--r--include/linux/fscrypt_common.h142
-rw-r--r--include/linux/fscrypt_notsupp.h39
-rw-r--r--include/linux/fscrypt_supp.h17
28 files changed, 1155 insertions, 279 deletions
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
new file mode 100644
index 000000000000..776ddc655f79
--- /dev/null
+++ b/Documentation/filesystems/fscrypt.rst
@@ -0,0 +1,610 @@
+=====================================
+Filesystem-level encryption (fscrypt)
+=====================================
+
+Introduction
+============
+
+fscrypt is a library which filesystems can hook into to support
+transparent encryption of files and directories.
+
+Note: "fscrypt" in this document refers to the kernel-level portion,
+implemented in ``fs/crypto/``, as opposed to the userspace tool
+`fscrypt <https://github.com/google/fscrypt>`_. This document only
+covers the kernel-level portion. For command-line examples of how to
+use encryption, see the documentation for the userspace tool `fscrypt
+<https://github.com/google/fscrypt>`_. Also, it is recommended to use
+the fscrypt userspace tool, or other existing userspace tools such as
+`fscryptctl <https://github.com/google/fscryptctl>`_ or `Android's key
+management system
+<https://source.android.com/security/encryption/file-based>`_, over
+using the kernel's API directly. Using existing tools reduces the
+chance of introducing your own security bugs. (Nevertheless, for
+completeness this documentation covers the kernel's API anyway.)
+
+Unlike dm-crypt, fscrypt operates at the filesystem level rather than
+at the block device level. This allows it to encrypt different files
+with different keys and to have unencrypted files on the same
+filesystem. This is useful for multi-user systems where each user's
+data-at-rest needs to be cryptographically isolated from the others.
+However, except for filenames, fscrypt does not encrypt filesystem
+metadata.
+
+Unlike eCryptfs, which is a stacked filesystem, fscrypt is integrated
+directly into supported filesystems --- currently ext4, F2FS, and
+UBIFS. This allows encrypted files to be read and written without
+caching both the decrypted and encrypted pages in the pagecache,
+thereby nearly halving the memory used and bringing it in line with
+unencrypted files. Similarly, half as many dentries and inodes are
+needed. eCryptfs also limits encrypted filenames to 143 bytes,
+causing application compatibility issues; fscrypt allows the full 255
+bytes (NAME_MAX). Finally, unlike eCryptfs, the fscrypt API can be
+used by unprivileged users, with no need to mount anything.
+
+fscrypt does not support encrypting files in-place. Instead, it
+supports marking an empty directory as encrypted. Then, after
+userspace provides the key, all regular files, directories, and
+symbolic links created in that directory tree are transparently
+encrypted.
+
+Threat model
+============
+
+Offline attacks
+---------------
+
+Provided that userspace chooses a strong encryption key, fscrypt
+protects the confidentiality of file contents and filenames in the
+event of a single point-in-time permanent offline compromise of the
+block device content. fscrypt does not protect the confidentiality of
+non-filename metadata, e.g. file sizes, file permissions, file
+timestamps, and extended attributes. Also, the existence and location
+of holes (unallocated blocks which logically contain all zeroes) in
+files is not protected.
+
+fscrypt is not guaranteed to protect confidentiality or authenticity
+if an attacker is able to manipulate the filesystem offline prior to
+an authorized user later accessing the filesystem.
+
+Online attacks
+--------------
+
+fscrypt (and storage encryption in general) can only provide limited
+protection, if any at all, against online attacks. In detail:
+
+fscrypt is only resistant to side-channel attacks, such as timing or
+electromagnetic attacks, to the extent that the underlying Linux
+Cryptographic API algorithms are. If a vulnerable algorithm is used,
+such as a table-based implementation of AES, it may be possible for an
+attacker to mount a side channel attack against the online system.
+Side channel attacks may also be mounted against applications
+consuming decrypted data.
+
+After an encryption key has been provided, fscrypt is not designed to
+hide the plaintext file contents or filenames from other users on the
+same system, regardless of the visibility of the keyring key.
+Instead, existing access control mechanisms such as file mode bits,
+POSIX ACLs, LSMs, or mount namespaces should be used for this purpose.
+Also note that as long as the encryption keys are *anywhere* in
+memory, an online attacker can necessarily compromise them by mounting
+a physical attack or by exploiting any kernel security vulnerability
+which provides an arbitrary memory read primitive.
+
+While it is ostensibly possible to "evict" keys from the system,
+recently accessed encrypted files will remain accessible at least
+until the filesystem is unmounted or the VFS caches are dropped, e.g.
+using ``echo 2 > /proc/sys/vm/drop_caches``. Even after that, if the
+RAM is compromised before being powered off, it will likely still be
+possible to recover portions of the plaintext file contents, if not
+some of the encryption keys as well. (Since Linux v4.12, all
+in-kernel keys related to fscrypt are sanitized before being freed.
+However, userspace would need to do its part as well.)
+
+Currently, fscrypt does not prevent a user from maliciously providing
+an incorrect key for another user's existing encrypted files. A
+protection against this is planned.
+
+Key hierarchy
+=============
+
+Master Keys
+-----------
+
+Each encrypted directory tree is protected by a *master key*. Master
+keys can be up to 64 bytes long, and must be at least as long as the
+greater of the key length needed by the contents and filenames
+encryption modes being used. For example, if AES-256-XTS is used for
+contents encryption, the master key must be 64 bytes (512 bits). Note
+that the XTS mode is defined to require a key twice as long as that
+required by the underlying block cipher.
+
+To "unlock" an encrypted directory tree, userspace must provide the
+appropriate master key. There can be any number of master keys, each
+of which protects any number of directory trees on any number of
+filesystems.
+
+Userspace should generate master keys either using a cryptographically
+secure random number generator, or by using a KDF (Key Derivation
+Function). Note that whenever a KDF is used to "stretch" a
+lower-entropy secret such as a passphrase, it is critical that a KDF
+designed for this purpose be used, such as scrypt, PBKDF2, or Argon2.
+
+Per-file keys
+-------------
+
+Master keys are not used to encrypt file contents or names directly.
+Instead, a unique key is derived for each encrypted file, including
+each regular file, directory, and symbolic link. This has several
+advantages:
+
+- In cryptosystems, the same key material should never be used for
+ different purposes. Using the master key as both an XTS key for
+ contents encryption and as a CTS-CBC key for filenames encryption
+ would violate this rule.
+- Per-file keys simplify the choice of IVs (Initialization Vectors)
+ for contents encryption. Without per-file keys, to ensure IV
+ uniqueness both the inode and logical block number would need to be
+ encoded in the IVs. This would make it impossible to renumber
+ inodes, which e.g. ``resize2fs`` can do when resizing an ext4
+ filesystem. With per-file keys, it is sufficient to encode just the
+ logical block number in the IVs.
+- Per-file keys strengthen the encryption of filenames, where IVs are
+ reused out of necessity. With a unique key per directory, IV reuse
+ is limited to within a single directory.
+- Per-file keys allow individual files to be securely erased simply by
+ securely erasing their keys. (Not yet implemented.)
+
+A KDF (Key Derivation Function) is used to derive per-file keys from
+the master key. This is done instead of wrapping a randomly-generated
+key for each file because it reduces the size of the encryption xattr,
+which for some filesystems makes the xattr more likely to fit in-line
+in the filesystem's inode table. With a KDF, only a 16-byte nonce is
+required --- long enough to make key reuse extremely unlikely. A
+wrapped key, on the other hand, would need to be up to 64 bytes ---
+the length of an AES-256-XTS key. Furthermore, currently there is no
+requirement to support unlocking a file with multiple alternative
+master keys or to support rotating master keys. Instead, the master
+keys may be wrapped in userspace, e.g. as done by the `fscrypt
+<https://github.com/google/fscrypt>`_ tool.
+
+The current KDF encrypts the master key using the 16-byte nonce as an
+AES-128-ECB key. The output is used as the derived key. If the
+output is longer than needed, then it is truncated to the needed
+length. Truncation is the norm for directories and symlinks, since
+those use the CTS-CBC encryption mode which requires a key half as
+long as that required by the XTS encryption mode.
+
+Note: this KDF meets the primary security requirement, which is to
+produce unique derived keys that preserve the entropy of the master
+key, assuming that the master key is already a good pseudorandom key.
+However, it is nonstandard and has some problems such as being
+reversible, so it is generally considered to be a mistake! It may be
+replaced with HKDF or another more standard KDF in the future.
+
+Encryption modes and usage
+==========================
+
+fscrypt allows one encryption mode to be specified for file contents
+and one encryption mode to be specified for filenames. Different
+directory trees are permitted to use different encryption modes.
+Currently, the following pairs of encryption modes are supported:
+
+- AES-256-XTS for contents and AES-256-CTS-CBC for filenames
+- AES-128-CBC for contents and AES-128-CTS-CBC for filenames
+
+It is strongly recommended to use AES-256-XTS for contents encryption.
+AES-128-CBC was added only for low-powered embedded devices with
+crypto accelerators such as CAAM or CESA that do not support XTS.
+
+New encryption modes can be added relatively easily, without changes
+to individual filesystems. However, authenticated encryption (AE)
+modes are not currently supported because of the difficulty of dealing
+with ciphertext expansion.
+
+For file contents, each filesystem block is encrypted independently.
+Currently, only the case where the filesystem block size is equal to
+the system's page size (usually 4096 bytes) is supported. With the
+XTS mode of operation (recommended), the logical block number within
+the file is used as the IV. With the CBC mode of operation (not
+recommended), ESSIV is used; specifically, the IV for CBC is the
+logical block number encrypted with AES-256, where the AES-256 key is
+the SHA-256 hash of the inode's data encryption key.
+
+For filenames, the full filename is encrypted at once. Because of the
+requirements to retain support for efficient directory lookups and
+filenames of up to 255 bytes, a constant initialization vector (IV) is
+used. However, each encrypted directory uses a unique key, which
+limits IV reuse to within a single directory. Note that IV reuse in
+the context of CTS-CBC encryption means that when the original
+filenames share a common prefix at least as long as the cipher block
+size (16 bytes for AES), the corresponding encrypted filenames will
+also share a common prefix. This is undesirable; it may be fixed in
+the future by switching to an encryption mode that is a strong
+pseudorandom permutation on arbitrary-length messages, e.g. the HEH
+(Hash-Encrypt-Hash) mode.
+
+Since filenames are encrypted with the CTS-CBC mode of operation, the
+plaintext and ciphertext filenames need not be multiples of the AES
+block size, i.e. 16 bytes. However, the minimum size that can be
+encrypted is 16 bytes, so shorter filenames are NUL-padded to 16 bytes
+before being encrypted. In addition, to reduce leakage of filename
+lengths via their ciphertexts, all filenames are NUL-padded to the
+next 4, 8, 16, or 32-byte boundary (configurable). 32 is recommended
+since this provides the best confidentiality, at the cost of making
+directory entries consume slightly more space. Note that since NUL
+(``\0``) is not otherwise a valid character in filenames, the padding
+will never produce duplicate plaintexts.
+
+Symbolic link targets are considered a type of filename and are
+encrypted in the same way as filenames in directory entries. Each
+symlink also uses a unique key; hence, the hardcoded IV is not a
+problem for symlinks.
+
+User API
+========
+
+Setting an encryption policy
+----------------------------
+
+The FS_IOC_SET_ENCRYPTION_POLICY ioctl sets an encryption policy on an
+empty directory or verifies that a directory or regular file already
+has the specified encryption policy. It takes in a pointer to a
+:c:type:`struct fscrypt_policy`, defined as follows::
+
+ #define FS_KEY_DESCRIPTOR_SIZE 8
+
+ struct fscrypt_policy {
+ __u8 version;
+ __u8 contents_encryption_mode;
+ __u8 filenames_encryption_mode;
+ __u8 flags;
+ __u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+ };
+
+This structure must be initialized as follows:
+
+- ``version`` must be 0.
+
+- ``contents_encryption_mode`` and ``filenames_encryption_mode`` must
+ be set to constants from ``<linux/fs.h>`` which identify the
+ encryption modes to use. If unsure, use
+ FS_ENCRYPTION_MODE_AES_256_XTS (1) for ``contents_encryption_mode``
+ and FS_ENCRYPTION_MODE_AES_256_CTS (4) for
+ ``filenames_encryption_mode``.
+
+- ``flags`` must be set to a value from ``<linux/fs.h>`` which
+ identifies the amount of NUL-padding to use when encrypting
+ filenames. If unsure, use FS_POLICY_FLAGS_PAD_32 (0x3).
+
+- ``master_key_descriptor`` specifies how to find the master key in
+ the keyring; see `Adding keys`_. It is up to userspace to choose a
+ unique ``master_key_descriptor`` for each master key. The e4crypt
+ and fscrypt tools use the first 8 bytes of
+ ``SHA-512(SHA-512(master_key))``, but this particular scheme is not
+ required. Also, the master key need not be in the keyring yet when
+ FS_IOC_SET_ENCRYPTION_POLICY is executed. However, it must be added
+ before any files can be created in the encrypted directory.
+
+If the file is not yet encrypted, then FS_IOC_SET_ENCRYPTION_POLICY
+verifies that the file is an empty directory. If so, the specified
+encryption policy is assigned to the directory, turning it into an
+encrypted directory. After that, and after providing the
+corresponding master key as described in `Adding keys`_, all regular
+files, directories (recursively), and symlinks created in the
+directory will be encrypted, inheriting the same encryption policy.
+The filenames in the directory's entries will be encrypted as well.
+
+Alternatively, if the file is already encrypted, then
+FS_IOC_SET_ENCRYPTION_POLICY validates that the specified encryption
+policy exactly matches the actual one. If they match, then the ioctl
+returns 0. Otherwise, it fails with EEXIST. This works on both
+regular files and directories, including nonempty directories.
+
+Note that the ext4 filesystem does not allow the root directory to be
+encrypted, even if it is empty. Users who want to encrypt an entire
+filesystem with one key should consider using dm-crypt instead.
+
+FS_IOC_SET_ENCRYPTION_POLICY can fail with the following errors:
+
+- ``EACCES``: the file is not owned by the process's uid, nor does the
+ process have the CAP_FOWNER capability in a namespace with the file
+ owner's uid mapped
+- ``EEXIST``: the file is already encrypted with an encryption policy
+ different from the one specified
+- ``EINVAL``: an invalid encryption policy was specified (invalid
+ version, mode(s), or flags)
+- ``ENOTDIR``: the file is unencrypted and is a regular file, not a
+ directory
+- ``ENOTEMPTY``: the file is unencrypted and is a nonempty directory
+- ``ENOTTY``: this type of filesystem does not implement encryption
+- ``EOPNOTSUPP``: the kernel was not configured with encryption
+ support for this filesystem, or the filesystem superblock has not
+ had encryption enabled on it. (For example, to use encryption on an
+ ext4 filesystem, CONFIG_EXT4_ENCRYPTION must be enabled in the
+ kernel config, and the superblock must have had the "encrypt"
+ feature flag enabled using ``tune2fs -O encrypt`` or ``mkfs.ext4 -O
+ encrypt``.)
+- ``EPERM``: this directory may not be encrypted, e.g. because it is
+ the root directory of an ext4 filesystem
+- ``EROFS``: the filesystem is readonly
+
+Getting an encryption policy
+----------------------------
+
+The FS_IOC_GET_ENCRYPTION_POLICY ioctl retrieves the :c:type:`struct
+fscrypt_policy`, if any, for a directory or regular file. See above
+for the struct definition. No additional permissions are required
+beyond the ability to open the file.
+
+FS_IOC_GET_ENCRYPTION_POLICY can fail with the following errors:
+
+- ``EINVAL``: the file is encrypted, but it uses an unrecognized
+ encryption context format
+- ``ENODATA``: the file is not encrypted
+- ``ENOTTY``: this type of filesystem does not implement encryption
+- ``EOPNOTSUPP``: the kernel was not configured with encryption
+ support for this filesystem
+
+Note: if you only need to know whether a file is encrypted or not, on
+most filesystems it is also possible to use the FS_IOC_GETFLAGS ioctl
+and check for FS_ENCRYPT_FL, or to use the statx() system call and
+check for STATX_ATTR_ENCRYPTED in stx_attributes.
+
+Getting the per-filesystem salt
+-------------------------------
+
+Some filesystems, such as ext4 and F2FS, also support the deprecated
+ioctl FS_IOC_GET_ENCRYPTION_PWSALT. This ioctl retrieves a randomly
+generated 16-byte value stored in the filesystem superblock. This
+value is intended to used as a salt when deriving an encryption key
+from a passphrase or other low-entropy user credential.
+
+FS_IOC_GET_ENCRYPTION_PWSALT is deprecated. Instead, prefer to
+generate and manage any needed salt(s) in userspace.
+
+Adding keys
+-----------
+
+To provide a master key, userspace must add it to an appropriate
+keyring using the add_key() system call (see:
+``Documentation/security/keys/core.rst``). The key type must be
+"logon"; keys of this type are kept in kernel memory and cannot be
+read back by userspace. The key description must be "fscrypt:"
+followed by the 16-character lower case hex representation of the
+``master_key_descriptor`` that was set in the encryption policy. The
+key payload must conform to the following structure::
+
+ #define FS_MAX_KEY_SIZE 64
+
+ struct fscrypt_key {
+ u32 mode;
+ u8 raw[FS_MAX_KEY_SIZE];
+ u32 size;
+ };
+
+``mode`` is ignored; just set it to 0. The actual key is provided in
+``raw`` with ``size`` indicating its size in bytes. That is, the
+bytes ``raw[0..size-1]`` (inclusive) are the actual key.
+
+The key description prefix "fscrypt:" may alternatively be replaced
+with a filesystem-specific prefix such as "ext4:". However, the
+filesystem-specific prefixes are deprecated and should not be used in
+new programs.
+
+There are several different types of keyrings in which encryption keys
+may be placed, such as a session keyring, a user session keyring, or a
+user keyring. Each key must be placed in a keyring that is "attached"
+to all processes that might need to access files encrypted with it, in
+the sense that request_key() will find the key. Generally, if only
+processes belonging to a specific user need to access a given
+encrypted directory and no session keyring has been installed, then
+that directory's key should be placed in that user's user session
+keyring or user keyring. Otherwise, a session keyring should be
+installed if needed, and the key should be linked into that session
+keyring, or in a keyring linked into that session keyring.
+
+Note: introducing the complex visibility semantics of keyrings here
+was arguably a mistake --- especially given that by design, after any
+process successfully opens an encrypted file (thereby setting up the
+per-file key), possessing the keyring key is not actually required for
+any process to read/write the file until its in-memory inode is
+evicted. In the future there probably should be a way to provide keys
+directly to the filesystem instead, which would make the intended
+semantics clearer.
+
+Access semantics
+================
+
+With the key
+------------
+
+With the encryption key, encrypted regular files, directories, and
+symlinks behave very similarly to their unencrypted counterparts ---
+after all, the encryption is intended to be transparent. However,
+astute users may notice some differences in behavior:
+
+- Unencrypted files, or files encrypted with a different encryption
+ policy (i.e. different key, modes, or flags), cannot be renamed or
+ linked into an encrypted directory; see `Encryption policy
+ enforcement`_. Attempts to do so will fail with EPERM. However,
+ encrypted files can be renamed within an encrypted directory, or
+ into an unencrypted directory.
+
+- Direct I/O is not supported on encrypted files. Attempts to use
+ direct I/O on such files will fall back to buffered I/O.
+
+- The fallocate operations FALLOC_FL_COLLAPSE_RANGE,
+ FALLOC_FL_INSERT_RANGE, and FALLOC_FL_ZERO_RANGE are not supported
+ on encrypted files and will fail with EOPNOTSUPP.
+
+- Online defragmentation of encrypted files is not supported. The
+ EXT4_IOC_MOVE_EXT and F2FS_IOC_MOVE_RANGE ioctls will fail with
+ EOPNOTSUPP.
+
+- The ext4 filesystem does not support data journaling with encrypted
+ regular files. It will fall back to ordered data mode instead.
+
+- DAX (Direct Access) is not supported on encrypted files.
+
+- The st_size of an encrypted symlink will not necessarily give the
+ length of the symlink target as required by POSIX. It will actually
+ give the length of the ciphertext, which may be slightly longer than
+ the plaintext due to the NUL-padding.
+
+Note that mmap *is* supported. This is possible because the pagecache
+for an encrypted file contains the plaintext, not the ciphertext.
+
+Without the key
+---------------
+
+Some filesystem operations may be performed on encrypted regular
+files, directories, and symlinks even before their encryption key has
+been provided:
+
+- File metadata may be read, e.g. using stat().
+
+- Directories may be listed, in which case the filenames will be
+ listed in an encoded form derived from their ciphertext. The
+ current encoding algorithm is described in `Filename hashing and
+ encoding`_. The algorithm is subject to change, but it is
+ guaranteed that the presented filenames will be no longer than
+ NAME_MAX bytes, will not contain the ``/`` or ``\0`` characters, and
+ will uniquely identify directory entries.
+
+ The ``.`` and ``..`` directory entries are special. They are always
+ present and are not encrypted or encoded.
+
+- Files may be deleted. That is, nondirectory files may be deleted
+ with unlink() as usual, and empty directories may be deleted with
+ rmdir() as usual. Therefore, ``rm`` and ``rm -r`` will work as
+ expected.
+
+- Symlink targets may be read and followed, but they will be presented
+ in encrypted form, similar to filenames in directories. Hence, they
+ are unlikely to point to anywhere useful.
+
+Without the key, regular files cannot be opened or truncated.
+Attempts to do so will fail with ENOKEY. This implies that any
+regular file operations that require a file descriptor, such as
+read(), write(), mmap(), fallocate(), and ioctl(), are also forbidden.
+
+Also without the key, files of any type (including directories) cannot
+be created or linked into an encrypted directory, nor can a name in an
+encrypted directory be the source or target of a rename, nor can an
+O_TMPFILE temporary file be created in an encrypted directory. All
+such operations will fail with ENOKEY.
+
+It is not currently possible to backup and restore encrypted files
+without the encryption key. This would require special APIs which
+have not yet been implemented.
+
+Encryption policy enforcement
+=============================
+
+After an encryption policy has been set on a directory, all regular
+files, directories, and symbolic links created in that directory
+(recursively) will inherit that encryption policy. Special files ---
+that is, named pipes, device nodes, and UNIX domain sockets --- will
+not be encrypted.
+
+Except for those special files, it is forbidden to have unencrypted
+files, or files encrypted with a different encryption policy, in an
+encrypted directory tree. Attempts to link or rename such a file into
+an encrypted directory will fail with EPERM. This is also enforced
+during ->lookup() to provide limited protection against offline
+attacks that try to disable or downgrade encryption in known locations
+where applications may later write sensitive data. It is recommended
+that systems implementing a form of "verified boot" take advantage of
+this by validating all top-level encryption policies prior to access.
+
+Implementation details
+======================
+
+Encryption context
+------------------
+
+An encryption policy is represented on-disk by a :c:type:`struct
+fscrypt_context`. It is up to individual filesystems to decide where
+to store it, but normally it would be stored in a hidden extended
+attribute. It should *not* be exposed by the xattr-related system
+calls such as getxattr() and setxattr() because of the special
+semantics of the encryption xattr. (In particular, there would be
+much confusion if an encryption policy were to be added to or removed
+from anything other than an empty directory.) The struct is defined
+as follows::
+
+ #define FS_KEY_DESCRIPTOR_SIZE 8
+ #define FS_KEY_DERIVATION_NONCE_SIZE 16
+
+ struct fscrypt_context {
+ u8 format;
+ u8 contents_encryption_mode;
+ u8 filenames_encryption_mode;
+ u8 flags;
+ u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+ u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
+ };
+
+Note that :c:type:`struct fscrypt_context` contains the same
+information as :c:type:`struct fscrypt_policy` (see `Setting an
+encryption policy`_), except that :c:type:`struct fscrypt_context`
+also contains a nonce. The nonce is randomly generated by the kernel
+and is used to derive the inode's encryption key as described in
+`Per-file keys`_.
+
+Data path changes
+-----------------
+
+For the read path (->readpage()) of regular files, filesystems can
+read the ciphertext into the page cache and decrypt it in-place. The
+page lock must be held until decryption has finished, to prevent the
+page from becoming visible to userspace prematurely.
+
+For the write path (->writepage()) of regular files, filesystems
+cannot encrypt data in-place in the page cache, since the cached
+plaintext must be preserved. Instead, filesystems must encrypt into a
+temporary buffer or "bounce page", then write out the temporary
+buffer. Some filesystems, such as UBIFS, already use temporary
+buffers regardless of encryption. Other filesystems, such as ext4 and
+F2FS, have to allocate bounce pages specially for encryption.
+
+Filename hashing and encoding
+-----------------------------
+
+Modern filesystems accelerate directory lookups by using indexed
+directories. An indexed directory is organized as a tree keyed by
+filename hashes. When a ->lookup() is requested, the filesystem
+normally hashes the filename being looked up so that it can quickly
+find the corresponding directory entry, if any.
+
+With encryption, lookups must be supported and efficient both with and
+without the encryption key. Clearly, it would not work to hash the
+plaintext filenames, since the plaintext filenames are unavailable
+without the key. (Hashing the plaintext filenames would also make it
+impossible for the filesystem's fsck tool to optimize encrypted
+directories.) Instead, filesystems hash the ciphertext filenames,
+i.e. the bytes actually stored on-disk in the directory entries. When
+asked to do a ->lookup() with the key, the filesystem just encrypts
+the user-supplied name to get the ciphertext.
+
+Lookups without the key are more complicated. The raw ciphertext may
+contain the ``\0`` and ``/`` characters, which are illegal in
+filenames. Therefore, readdir() must base64-encode the ciphertext for
+presentation. For most filenames, this works fine; on ->lookup(), the
+filesystem just base64-decodes the user-supplied name to get back to
+the raw ciphertext.
+
+However, for very long filenames, base64 encoding would cause the
+filename length to exceed NAME_MAX. To prevent this, readdir()
+actually presents long filenames in an abbreviated form which encodes
+a strong "hash" of the ciphertext filename, along with the optional
+filesystem-specific hash(es) needed for directory lookups. This
+allows the filesystem to still, with a high degree of confidence, map
+the filename given in ->lookup() back to a particular directory entry
+that was previously listed by readdir(). See :c:type:`struct
+fscrypt_digested_name` in the source for more details.
+
+Note that the precise way that filenames are presented to userspace
+without the key is subject to change in the future. It is only meant
+as a way to temporarily present valid filenames so that commands like
+``rm -r`` work as expected on encrypted directories.
diff --git a/Documentation/filesystems/index.rst b/Documentation/filesystems/index.rst
index 256e10eedba4..53b89d0edc15 100644
--- a/Documentation/filesystems/index.rst
+++ b/Documentation/filesystems/index.rst
@@ -315,3 +315,14 @@ exported for use by modules.
:internal:
.. kernel-doc:: fs/pipe.c
+
+Encryption API
+==============
+
+A library which filesystems can hook into to support transparent
+encryption of files and directories.
+
+.. toctree::
+ :maxdepth: 2
+
+ fscrypt
diff --git a/MAINTAINERS b/MAINTAINERS
index 9a9343a24528..e372994747b7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5664,6 +5664,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt.git
S: Supported
F: fs/crypto/
F: include/linux/fscrypt*.h
+F: Documentation/filesystems/fscrypt.rst
FUJITSU FR-V (FRV) PORT
S: Orphan
diff --git a/fs/crypto/Makefile b/fs/crypto/Makefile
index 9f6607f17b53..cb496989a6b6 100644
--- a/fs/crypto/Makefile
+++ b/fs/crypto/Makefile
@@ -1,4 +1,4 @@
obj-$(CONFIG_FS_ENCRYPTION) += fscrypto.o
-fscrypto-y := crypto.o fname.o policy.o keyinfo.o
+fscrypto-y := crypto.o fname.o hooks.o keyinfo.o policy.o
fscrypto-$(CONFIG_BLOCK) += bio.o
diff --git a/fs/crypto/crypto.c b/fs/crypto/crypto.c
index 80a3cada53de..732a786cce9d 100644
--- a/fs/crypto/crypto.c
+++ b/fs/crypto/crypto.c
@@ -320,7 +320,7 @@ static int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags)
return -ECHILD;
dir = dget_parent(dentry);
- if (!d_inode(dir)->i_sb->s_cop->is_encrypted(d_inode(dir))) {
+ if (!IS_ENCRYPTED(d_inode(dir))) {
dput(dir);
return 0;
}
@@ -390,11 +390,8 @@ int fscrypt_initialize(unsigned int cop_flags)
{
int i, res = -ENOMEM;
- /*
- * No need to allocate a bounce page pool if there already is one or
- * this FS won't use it.
- */
- if (cop_flags & FS_CFLG_OWN_PAGES || fscrypt_bounce_page_pool)
+ /* No need to allocate a bounce page pool if this FS won't use it. */
+ if (cop_flags & FS_CFLG_OWN_PAGES)
return 0;
mutex_lock(&fscrypt_init_mutex);
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index 0b94cd2b3222..305541bcd108 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -359,8 +359,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
memset(fname, 0, sizeof(struct fscrypt_name));
fname->usr_fname = iname;
- if (!dir->i_sb->s_cop->is_encrypted(dir) ||
- fscrypt_is_dot_dotdot(iname)) {
+ if (!IS_ENCRYPTED(dir) || fscrypt_is_dot_dotdot(iname)) {
fname->disk_name.name = (unsigned char *)iname->name;
fname->disk_name.len = iname->len;
return 0;
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h
index e54e602b473f..c0b4f5597e1a 100644
--- a/fs/crypto/fscrypt_private.h
+++ b/fs/crypto/fscrypt_private.h
@@ -12,7 +12,8 @@
#ifndef _FSCRYPT_PRIVATE_H
#define _FSCRYPT_PRIVATE_H
-#include <linux/fscrypt_supp.h>
+#define __FS_HAS_ENCRYPTION 1
+#include <linux/fscrypt.h>
#include <crypto/hash.h>
/* Encryption parameters */
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c
new file mode 100644
index 000000000000..9f5fb2eb9cf7
--- /dev/null
+++ b/fs/crypto/hooks.c
@@ -0,0 +1,112 @@
+/*
+ * fs/crypto/hooks.c
+ *
+ * Encryption hooks for higher-level filesystem operations.
+ */
+
+#include <linux/ratelimit.h>
+#include "fscrypt_private.h"
+
+/**
+ * fscrypt_file_open - prepare to open a possibly-encrypted regular file
+ * @inode: the inode being opened
+ * @filp: the struct file being set up
+ *
+ * Currently, an encrypted regular file can only be opened if its encryption key
+ * is available; access to the raw encrypted contents is not supported.
+ * Therefore, we first set up the inode's encryption key (if not already done)
+ * and return an error if it's unavailable.
+ *
+ * We also verify that if the parent directory (from the path via which the file
+ * is being opened) is encrypted, then the inode being opened uses the same
+ * encryption policy. This is needed as part of the enforcement that all files
+ * in an encrypted directory tree use the same encryption policy, as a
+ * protection against certain types of offline attacks. Note that this check is
+ * needed even when opening an *unencrypted* file, since it's forbidden to have
+ * an unencrypted file in an encrypted directory.
+ *
+ * Return: 0 on success, -ENOKEY if the key is missing, or another -errno code
+ */
+int fscrypt_file_open(struct inode *inode, struct file *filp)
+{
+ int err;
+ struct dentry *dir;
+
+ err = fscrypt_require_key(inode);
+ if (err)
+ return err;
+
+ dir = dget_parent(file_dentry(filp));
+ if (IS_ENCRYPTED(d_inode(dir)) &&
+ !fscrypt_has_permitted_context(d_inode(dir), inode)) {
+ pr_warn_ratelimited("fscrypt: inconsistent encryption contexts: %lu/%lu",
+ d_inode(dir)->i_ino, inode->i_ino);
+ err = -EPERM;
+ }
+ dput(dir);
+ return err;
+}
+EXPORT_SYMBOL_GPL(fscrypt_file_open);
+
+int __fscrypt_prepare_link(struct inode *inode, struct inode *dir)
+{
+ int err;
+
+ err = fscrypt_require_key(dir);
+ if (err)
+ return err;
+
+ if (!fscrypt_has_permitted_context(dir, inode))
+ return -EPERM;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__fscrypt_prepare_link);
+
+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;
+
+ if (old_dir != new_dir) {
+ if (IS_ENCRYPTED(new_dir) &&
+ !fscrypt_has_permitted_context(new_dir,
+ d_inode(old_dentry)))
+ return -EPERM;
+
+ if ((flags & RENAME_EXCHANGE) &&
+ IS_ENCRYPTED(old_dir) &&
+ !fscrypt_has_permitted_context(old_dir,
+ d_inode(new_dentry)))
+ return -EPERM;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__fscrypt_prepare_rename);
+
+int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry)
+{
+ int err = fscrypt_get_encryption_info(dir);
+
+ if (err)
+ return err;
+
+ if (fscrypt_has_encryption_key(dir)) {
+ spin_lock(&dentry->d_lock);
+ dentry->d_flags |= DCACHE_ENCRYPTED_WITH_KEY;
+ spin_unlock(&dentry->d_lock);
+ }
+
+ d_set_d_op(dentry, &fscrypt_d_ops);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup);
diff --git a/fs/crypto/keyinfo.c b/fs/crypto/keyinfo.c
index 4486b3eecc27..5e6e846f5a24 100644
--- a/fs/crypto/keyinfo.c
+++ b/fs/crypto/keyinfo.c
@@ -259,7 +259,7 @@ int fscrypt_get_encryption_info(struct inode *inode)
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
if (res < 0) {
if (!fscrypt_dummy_context_enabled(inode) ||
- inode->i_sb->s_cop->is_encrypted(inode))
+ IS_ENCRYPTED(inode))
return res;
/* Fake up a context for an unencrypted directory */
memset(&ctx, 0, sizeof(ctx));
diff --git a/fs/crypto/policy.c b/fs/crypto/policy.c
index a120649beeca..c6d431a5cce9 100644
--- a/fs/crypto/policy.c
+++ b/fs/crypto/policy.c
@@ -110,7 +110,7 @@ int fscrypt_ioctl_get_policy(struct file *filp, void __user *arg)
struct fscrypt_policy policy;
int res;
- if (!inode->i_sb->s_cop->is_encrypted(inode))
+ if (!IS_ENCRYPTED(inode))
return -ENODATA;
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
@@ -167,11 +167,11 @@ int fscrypt_has_permitted_context(struct inode *parent, struct inode *child)
return 1;
/* No restrictions if the parent directory is unencrypted */
- if (!cops->is_encrypted(parent))
+ if (!IS_ENCRYPTED(parent))
return 1;
/* Encrypted directories must not contain unencrypted files */
- if (!cops->is_encrypted(child))
+ if (!IS_ENCRYPTED(child))
return 0;
/*
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 58a0304566db..27f38bb5046d 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -34,17 +34,15 @@
#include <linux/percpu_counter.h>
#include <linux/ratelimit.h>
#include <crypto/hash.h>
-#ifdef CONFIG_EXT4_FS_ENCRYPTION
-#include <linux/fscrypt_supp.h>
-#else
-#include <linux/fscrypt_notsupp.h>
-#endif
#include <linux/falloc.h>
#include <linux/percpu-rwsem.h>
#ifdef __KERNEL__
#include <linux/compat.h>
#endif
+#define __FS_HAS_ENCRYPTION IS_ENABLED(CONFIG_EXT4_FS_ENCRYPTION)
+#include <linux/fscrypt.h>
+
/*
* The fourth extended filesystem constants/structures
*/
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 5cb9aa3ad249..b937078bcff3 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -365,7 +365,6 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
struct super_block *sb = inode->i_sb;
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct vfsmount *mnt = filp->f_path.mnt;
- struct dentry *dir;
struct path path;
char buf[64], *cp;
int ret;
@@ -405,25 +404,11 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
ext4_journal_stop(handle);
}
}
- if (ext4_encrypted_inode(inode)) {
- ret = fscrypt_get_encryption_info(inode);
- if (ret)
- return -EACCES;
- if (!fscrypt_has_encryption_key(inode))
- return -ENOKEY;
- }
- dir = dget_parent(file_dentry(filp));
- if (ext4_encrypted_inode(d_inode(dir)) &&
- !fscrypt_has_permitted_context(d_inode(dir), inode)) {
- ext4_warning(inode->i_sb,
- "Inconsistent encryption contexts: %lu/%lu",
- (unsigned long) d_inode(dir)->i_ino,
- (unsigned long) inode->i_ino);
- dput(dir);
- return -EPERM;
- }
- dput(dir);
+ ret = fscrypt_file_open(inode, filp);
+ if (ret)
+ return ret;
+
/*
* Set up the jbd2_inode if we are opening the inode for
* writing and the journal is present
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 90afeb7293a6..168a1b499cdf 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4590,10 +4590,13 @@ void ext4_set_inode_flags(struct inode *inode)
new_fl |= S_DIRSYNC;
if (test_opt(inode->i_sb, DAX) && S_ISREG(inode->i_mode) &&
!ext4_should_journal_data(inode) && !ext4_has_inline_data(inode) &&
- !ext4_encrypted_inode(inode))
+ !(flags & EXT4_ENCRYPT_FL))
new_fl |= S_DAX;
+ if (flags & EXT4_ENCRYPT_FL)
+ new_fl |= S_ENCRYPTED;
inode_set_flags(inode, new_fl,
- S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX);
+ S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX|
+ S_ENCRYPTED);
}
static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode,
@@ -5309,6 +5312,10 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
if (error)
return error;
+ error = fscrypt_prepare_setattr(dentry, attr);
+ if (error)
+ return error;
+
if (is_quota_modification(inode, attr)) {
error = dquot_initialize(inode);
if (error)
@@ -5354,14 +5361,6 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
loff_t oldsize = inode->i_size;
int shrink = (attr->ia_size <= inode->i_size);
- if (ext4_encrypted_inode(inode)) {
- error = fscrypt_get_encryption_info(inode);
- if (error)
- return error;
- if (!fscrypt_has_encryption_key(inode))
- return -ENOKEY;
- }
-
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index bd48a8d83961..798b3ac680db 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1539,24 +1539,14 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
struct inode *inode;
struct ext4_dir_entry_2 *de;
struct buffer_head *bh;
+ int err;
- if (ext4_encrypted_inode(dir)) {
- int res = fscrypt_get_encryption_info(dir);
-
- /*
- * DCACHE_ENCRYPTED_WITH_KEY is set if the dentry is
- * created while the directory was encrypted and we
- * have access to the key.
- */
- if (fscrypt_has_encryption_key(dir))
- fscrypt_set_encrypted_dentry(dentry);
- fscrypt_set_d_op(dentry);
- if (res && res != -ENOKEY)
- return ERR_PTR(res);
- }
+ err = fscrypt_prepare_lookup(dir, dentry, flags);
+ if (err)
+ return ERR_PTR(err);
- if (dentry->d_name.len > EXT4_NAME_LEN)
- return ERR_PTR(-ENAMETOOLONG);
+ if (dentry->d_name.len > EXT4_NAME_LEN)
+ return ERR_PTR(-ENAMETOOLONG);
bh = ext4_find_entry(dir, &dentry->d_name, &de, NULL);
if (IS_ERR(bh))
@@ -3222,9 +3212,10 @@ static int ext4_link(struct dentry *old_dentry,
if (inode->i_nlink >= EXT4_LINK_MAX)
return -EMLINK;
- if (ext4_encrypted_inode(dir) &&
- !fscrypt_has_permitted_context(dir, inode))
- return -EPERM;
+
+ err = fscrypt_prepare_link(old_dentry, dir, dentry);
+ if (err)
+ return err;
if ((ext4_test_inode_flag(dir, EXT4_INODE_PROJINHERIT)) &&
(!projid_eq(EXT4_I(dir)->i_projid,
@@ -3516,12 +3507,6 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
EXT4_I(old_dentry->d_inode)->i_projid)))
return -EXDEV;
- if ((ext4_encrypted_inode(old_dir) &&
- !fscrypt_has_encryption_key(old_dir)) ||
- (ext4_encrypted_inode(new_dir) &&
- !fscrypt_has_encryption_key(new_dir)))
- return -ENOKEY;
-
retval = dquot_initialize(old.dir);
if (retval)
return retval;
@@ -3550,13 +3535,6 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
if (!old.bh || le32_to_cpu(old.de->inode) != old.inode->i_ino)
goto end_rename;
- if ((old.dir != new.dir) &&
- ext4_encrypted_inode(new.dir) &&
- !fscrypt_has_permitted_context(new.dir, old.inode)) {
- retval = -EPERM;
- goto end_rename;
- }
-
new.bh = ext4_find_entry(new.dir, &new.dentry->d_name,
&new.de, &new.inlined);
if (IS_ERR(new.bh)) {
@@ -3722,19 +3700,6 @@ static int ext4_cross_rename(struct inode *old_dir, struct dentry *old_dentry,
int retval;
struct timespec ctime;
- if ((ext4_encrypted_inode(old_dir) &&
- !fscrypt_has_encryption_key(old_dir)) ||
- (ext4_encrypted_inode(new_dir) &&
- !fscrypt_has_encryption_key(new_dir)))
- return -ENOKEY;
-
- if ((ext4_encrypted_inode(old_dir) ||
- ext4_encrypted_inode(new_dir)) &&
- (old_dir != new_dir) &&
- (!fscrypt_has_permitted_context(new_dir, old.inode) ||
- !fscrypt_has_permitted_context(old_dir, new.inode)))
- return -EPERM;
-
if ((ext4_test_inode_flag(new_dir, EXT4_INODE_PROJINHERIT) &&
!projid_eq(EXT4_I(new_dir)->i_projid,
EXT4_I(old_dentry->d_inode)->i_projid)) ||
@@ -3861,12 +3826,19 @@ static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
struct inode *new_dir, struct dentry *new_dentry,
unsigned int flags)
{
+ int err;
+
if (unlikely(ext4_forced_shutdown(EXT4_SB(old_dir->i_sb))))
return -EIO;
if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
return -EINVAL;
+ err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
+ flags);
+ if (err)
+ return err;
+
if (flags & RENAME_EXCHANGE) {
return ext4_cross_rename(old_dir, old_dentry,
new_dir, new_dentry);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b0915b734a38..e2557711a11c 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1181,7 +1181,8 @@ static int ext4_set_context(struct inode *inode, const void *ctx, size_t len,
ext4_clear_inode_state(inode,
EXT4_STATE_MAY_INLINE_DATA);
/*
- * Update inode->i_flags - e.g. S_DAX may get disabled
+ * Update inode->i_flags - S_ENCRYPTED will be enabled,
+ * S_DAX may be disabled
*/
ext4_set_inode_flags(inode);
}
@@ -1206,7 +1207,10 @@ retry:
ctx, len, 0);
if (!res) {
ext4_set_inode_flag(inode, EXT4_INODE_ENCRYPT);
- /* Update inode->i_flags - e.g. S_DAX may get disabled */
+ /*
+ * Update inode->i_flags - S_ENCRYPTED will be enabled,
+ * S_DAX may be disabled
+ */
ext4_set_inode_flags(inode);
res = ext4_mark_inode_dirty(handle, inode);
if (res)
@@ -1237,14 +1241,9 @@ static const struct fscrypt_operations ext4_cryptops = {
.get_context = ext4_get_context,
.set_context = ext4_set_context,
.dummy_context = ext4_dummy_context,
- .is_encrypted = ext4_encrypted_inode,
.empty_dir = ext4_empty_dir,
.max_namelen = ext4_max_namelen,
};
-#else
-static const struct fscrypt_operations ext4_cryptops = {
- .is_encrypted = ext4_encrypted_inode,
-};
#endif
#ifdef CONFIG_QUOTA
@@ -3996,7 +3995,9 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
sb->s_op = &ext4_sops;
sb->s_export_op = &ext4_export_ops;
sb->s_xattr = ext4_xattr_handlers;
+#ifdef CONFIG_EXT4_FS_ENCRYPTION
sb->s_cop = &ext4_cryptops;
+#endif
#ifdef CONFIG_QUOTA
sb->dq_op = &ext4_quota_operations;
if (ext4_has_feature_quota(sb))
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4b4a72f392be..115204fdefcc 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -23,13 +23,11 @@
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/quotaops.h>
-#ifdef CONFIG_F2FS_FS_ENCRYPTION
-#include <linux/fscrypt_supp.h>
-#else
-#include <linux/fscrypt_notsupp.h>
-#endif
#include <crypto/hash.h>
+#define __FS_HAS_ENCRYPTION IS_ENABLED(CONFIG_F2FS_FS_ENCRYPTION)
+#include <linux/fscrypt.h>
+
#ifdef CONFIG_F2FS_CHECK_FS
#define f2fs_bug_on(sbi, condition) BUG_ON(condition)
#else
@@ -2949,6 +2947,7 @@ static inline void f2fs_set_encrypted_inode(struct inode *inode)
{
#ifdef CONFIG_F2FS_FS_ENCRYPTION
file_set_encrypt(inode);
+ inode->i_flags |= S_ENCRYPTED;
#endif
}
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 50c88e37ed66..53fb08810ee9 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -43,8 +43,11 @@ void f2fs_set_inode_flags(struct inode *inode)
new_fl |= S_NOATIME;
if (flags & FS_DIRSYNC_FL)
new_fl |= S_DIRSYNC;
+ if (f2fs_encrypted_inode(inode))
+ new_fl |= S_ENCRYPTED;
inode_set_flags(inode, new_fl,
- S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
+ S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|
+ S_ENCRYPTED);
}
static void __get_inode_rdev(struct inode *inode, struct f2fs_inode *ri)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 933c3d529e65..97e03c637e90 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1594,14 +1594,9 @@ static const struct fscrypt_operations f2fs_cryptops = {
.key_prefix = "f2fs:",
.get_context = f2fs_get_context,
.set_context = f2fs_set_context,
- .is_encrypted = f2fs_encrypted_inode,
.empty_dir = f2fs_empty_dir,
.max_namelen = f2fs_max_namelen,
};
-#else
-static const struct fscrypt_operations f2fs_cryptops = {
- .is_encrypted = f2fs_encrypted_inode,
-};
#endif
static struct inode *f2fs_nfs_get_inode(struct super_block *sb,
@@ -2320,7 +2315,9 @@ try_onemore:
#endif
sb->s_op = &f2fs_sops;
+#ifdef CONFIG_F2FS_FS_ENCRYPTION
sb->s_cop = &f2fs_cryptops;
+#endif
sb->s_xattr = f2fs_xattr_handlers;
sb->s_export_op = &f2fs_export_ops;
sb->s_magic = F2FS_SUPER_MAGIC;
diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
index 16a5d5c82073..616a688f5d8f 100644
--- a/fs/ubifs/crypto.c
+++ b/fs/ubifs/crypto.c
@@ -88,7 +88,6 @@ const struct fscrypt_operations ubifs_crypt_operations = {
.key_prefix = "ubifs:",
.get_context = ubifs_crypt_get_context,
.set_context = ubifs_crypt_set_context,
- .is_encrypted = __ubifs_crypt_is_encrypted,
.empty_dir = ubifs_crypt_empty_dir,
.max_namelen = ubifs_crypt_max_namelen,
};
diff --git a/fs/ubifs/ioctl.c b/fs/ubifs/ioctl.c
index fdc311246807..0164bcc827f8 100644
--- a/fs/ubifs/ioctl.c
+++ b/fs/ubifs/ioctl.c
@@ -38,7 +38,8 @@ void ubifs_set_inode_flags(struct inode *inode)
{
unsigned int flags = ubifs_inode(inode)->flags;
- inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_DIRSYNC);
+ inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_DIRSYNC |
+ S_ENCRYPTED);
if (flags & UBIFS_SYNC_FL)
inode->i_flags |= S_SYNC;
if (flags & UBIFS_APPEND_FL)
@@ -47,6 +48,8 @@ void ubifs_set_inode_flags(struct inode *inode)
inode->i_flags |= S_IMMUTABLE;
if (flags & UBIFS_DIRSYNC_FL)
inode->i_flags |= S_DIRSYNC;
+ if (flags & UBIFS_CRYPT_FL)
+ inode->i_flags |= S_ENCRYPTED;
}
/*
diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 5496b17b959c..7503e7cdf870 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -2007,12 +2007,6 @@ static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi)
return c;
}
-#ifndef CONFIG_UBIFS_FS_ENCRYPTION
-const struct fscrypt_operations ubifs_crypt_operations = {
- .is_encrypted = __ubifs_crypt_is_encrypted,
-};
-#endif
-
static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
{
struct ubifs_info *c = sb->s_fs_info;
@@ -2055,7 +2049,9 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
sb->s_op = &ubifs_super_operations;
sb->s_xattr = ubifs_xattr_handlers;
+#ifdef CONFIG_UBIFS_FS_ENCRYPTION
sb->s_cop = &ubifs_crypt_operations;
+#endif
mutex_lock(&c->umount_mutex);
err = mount_ubifs(c);
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index cd43651f1731..63c7468147eb 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -38,12 +38,11 @@
#include <linux/backing-dev.h>
#include <linux/security.h>
#include <linux/xattr.h>
-#ifdef CONFIG_UBIFS_FS_ENCRYPTION
-#include <linux/fscrypt_supp.h>
-#else
-#include <linux/fscrypt_notsupp.h>
-#endif
#include <linux/random.h>
+
+#define __FS_HAS_ENCRYPTION IS_ENABLED(CONFIG_UBIFS_FS_ENCRYPTION)
+#include <linux/fscrypt.h>
+
#include "ubifs-media.h"
/* Version of this UBIFS implementation */
@@ -1835,18 +1834,13 @@ int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
extern const struct fscrypt_operations ubifs_crypt_operations;
-static inline bool __ubifs_crypt_is_encrypted(struct inode *inode)
+static inline bool ubifs_crypt_is_encrypted(const struct inode *inode)
{
- struct ubifs_inode *ui = ubifs_inode(inode);
+ const struct ubifs_inode *ui = ubifs_inode(inode);
return ui->flags & UBIFS_CRYPT_FL;
}
-static inline bool ubifs_crypt_is_encrypted(const struct inode *inode)
-{
- return __ubifs_crypt_is_encrypted((struct inode *)inode);
-}
-
/* Normal UBIFS messages */
__printf(2, 3)
void ubifs_msg(const struct ubifs_info *c, const char *fmt, ...);
diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index c13eae819cbc..5ddc89d564fd 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -170,6 +170,7 @@ static int create_xattr(struct ubifs_info *c, struct inode *host,
err = ubifs_jnl_update(c, host, nm, inode, 0, 1);
if (err)
goto out_cancel;
+ ubifs_set_inode_flags(host);
mutex_unlock(&host_ui->ui_mutex);
ubifs_release_budget(c, &req);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e1f75a3b4af5..269086440071 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1854,6 +1854,7 @@ struct super_operations {
#else
#define S_DAX 0 /* Make all the DAX code disappear */
#endif
+#define S_ENCRYPTED 16384 /* Encrypted file (using fs/crypto/) */
/*
* Note that nosuid etc flags are inode-specific: setting some file-system
@@ -1893,6 +1894,7 @@ static inline bool sb_rdonly(const struct super_block *sb) { return sb->s_flags
#define IS_AUTOMOUNT(inode) ((inode)->i_flags & S_AUTOMOUNT)
#define IS_NOSEC(inode) ((inode)->i_flags & S_NOSEC)
#define IS_DAX(inode) ((inode)->i_flags & S_DAX)
+#define IS_ENCRYPTED(inode) ((inode)->i_flags & S_ENCRYPTED)
#define IS_WHITEOUT(inode) (S_ISCHR(inode->i_mode) && \
(inode)->i_rdev == WHITEOUT_DEV)
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
new file mode 100644
index 000000000000..08b4b40c5aa8
--- /dev/null
+++ b/include/linux/fscrypt.h
@@ -0,0 +1,294 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * fscrypt.h: declarations for per-file encryption
+ *
+ * Filesystems that implement per-file encryption include this header
+ * file with the __FS_HAS_ENCRYPTION set according to whether that filesystem
+ * is being built with encryption support or not.
+ *
+ * Copyright (C) 2015, Google, Inc.
+ *
+ * Written by Michael Halcrow, 2015.
+ * Modified by Jaegeuk Kim, 2015.
+ */
+#ifndef _LINUX_FSCRYPT_H
+#define _LINUX_FSCRYPT_H
+
+#include <linux/key.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/bio.h>
+#include <linux/dcache.h>
+#include <crypto/skcipher.h>
+#include <uapi/linux/fs.h>
+
+#define FS_CRYPTO_BLOCK_SIZE 16
+
+struct fscrypt_info;
+
+struct fscrypt_ctx {
+ union {
+ struct {
+ struct page *bounce_page; /* Ciphertext page */
+ struct page *control_page; /* Original page */
+ } w;
+ struct {
+ struct bio *bio;
+ struct work_struct work;
+ } r;
+ struct list_head free_list; /* Free list */
+ };
+ u8 flags; /* Flags */
+};
+
+/**
+ * For encrypted symlinks, the ciphertext length is stored at the beginning
+ * of the string in little-endian format.
+ */
+struct fscrypt_symlink_data {
+ __le16 len;
+ char encrypted_path[1];
+} __packed;
+
+struct fscrypt_str {
+ unsigned char *name;
+ u32 len;
+};
+
+struct fscrypt_name {
+ const struct qstr *usr_fname;
+ struct fscrypt_str disk_name;
+ u32 hash;
+ u32 minor_hash;
+ struct fscrypt_str crypto_buf;
+};
+
+#define FSTR_INIT(n, l) { .name = n, .len = l }
+#define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len)
+#define fname_name(p) ((p)->disk_name.name)
+#define fname_len(p) ((p)->disk_name.len)
+
+/*
+ * fscrypt superblock flags
+ */
+#define FS_CFLG_OWN_PAGES (1U << 1)
+
+/*
+ * crypto opertions for filesystems
+ */
+struct fscrypt_operations {
+ unsigned int flags;
+ const char *key_prefix;
+ int (*get_context)(struct inode *, void *, size_t);
+ int (*set_context)(struct inode *, const void *, size_t, void *);
+ bool (*dummy_context)(struct inode *);
+ bool (*empty_dir)(struct inode *);
+ unsigned (*max_namelen)(struct inode *);
+};
+
+/* Maximum value for the third parameter of fscrypt_operations.set_context(). */
+#define FSCRYPT_SET_CONTEXT_MAX_SIZE 28
+
+static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
+{
+ if (inode->i_sb->s_cop->dummy_context &&
+ inode->i_sb->s_cop->dummy_context(inode))
+ return true;
+ return false;
+}
+
+static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
+ u32 filenames_mode)
+{
+ if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
+ filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
+ return true;
+
+ if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
+ filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
+ return true;
+
+ return false;
+}
+
+static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
+{
+ if (str->len == 1 && str->name[0] == '.')
+ return true;
+
+ if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
+ return true;
+
+ return false;
+}
+
+#if __FS_HAS_ENCRYPTION
+
+static inline struct page *fscrypt_control_page(struct page *page)
+{
+ return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
+}
+
+static inline bool fscrypt_has_encryption_key(const struct inode *inode)
+{
+ return (inode->i_crypt_info != NULL);
+}
+
+#include <linux/fscrypt_supp.h>
+
+#else /* !__FS_HAS_ENCRYPTION */
+
+static inline struct page *fscrypt_control_page(struct page *page)
+{
+ WARN_ON_ONCE(1);
+ return ERR_PTR(-EINVAL);
+}
+
+static inline bool fscrypt_has_encryption_key(const struct inode *inode)
+{
+ return 0;
+}
+
+#include <linux/fscrypt_notsupp.h>
+#endif /* __FS_HAS_ENCRYPTION */
+
+/**
+ * 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
+ * @dir: the target directory
+ * @dentry: negative dentry for the target filename
+ *
+ * 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.
+ *
+ * We also verify that the link will not violate the constraint that all files
+ * in an encrypted directory tree use the same encryption policy.
+ *
+ * Return: 0 on success, -ENOKEY if the directory's encryption key is missing,
+ * -EPERM if the link would result in an inconsistent encryption policy, or
+ * another -errno code.
+ */
+static inline int fscrypt_prepare_link(struct dentry *old_dentry,
+ struct inode *dir,
+ struct dentry *dentry)
+{
+ if (IS_ENCRYPTED(dir))
+ return __fscrypt_prepare_link(d_inode(old_dentry), dir);
+ return 0;
+}
+
+/**
+ * fscrypt_prepare_rename - prepare for a rename between possibly-encrypted directories
+ * @old_dir: source directory
+ * @old_dentry: dentry for source file
+ * @new_dir: target directory
+ * @new_dentry: dentry for target location (may be negative unless exchanging)
+ * @flags: rename flags (we care at least about %RENAME_EXCHANGE)
+ *
+ * Prepare for ->rename() where the source and/or target directories may be
+ * encrypted. 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. A rename to an existing name, on the other hand,
+ * *is* cryptographically possible without the key. However, we take the more
+ * conservative approach and just forbid all no-key renames.
+ *
+ * We also verify that the rename will not violate the constraint that all files
+ * in an encrypted directory tree use the same encryption policy.
+ *
+ * Return: 0 on success, -ENOKEY if an encryption key is missing, -EPERM if the
+ * rename would cause inconsistent encryption policies, or another -errno code.
+ */
+static inline int fscrypt_prepare_rename(struct inode *old_dir,
+ struct dentry *old_dentry,
+ struct inode *new_dir,
+ struct dentry *new_dentry,
+ unsigned int flags)
+{
+ if (IS_ENCRYPTED(old_dir) || IS_ENCRYPTED(new_dir))
+ return __fscrypt_prepare_rename(old_dir, old_dentry,
+ new_dir, new_dentry, flags);
+ return 0;
+}
+
+/**
+ * fscrypt_prepare_lookup - prepare to lookup a name in a possibly-encrypted directory
+ * @dir: directory being searched
+ * @dentry: filename being looked up
+ * @flags: lookup flags
+ *
+ * Prepare for ->lookup() in a directory which may be encrypted. 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.
+ *
+ * To allow invalidating stale dentries if the directory's encryption key is
+ * added later, we also install a custom ->d_revalidate() method and use the
+ * DCACHE_ENCRYPTED_WITH_KEY flag to indicate whether a given dentry is a
+ * plaintext name (flag set) or a ciphertext name (flag cleared).
+ *
+ * Return: 0 on success, -errno if a problem occurred while setting up the
+ * encryption key
+ */
+static inline int fscrypt_prepare_lookup(struct inode *dir,
+ struct dentry *dentry,
+ unsigned int flags)
+{
+ if (IS_ENCRYPTED(dir))
+ return __fscrypt_prepare_lookup(dir, dentry);
+ return 0;
+}
+
+/**
+ * fscrypt_prepare_setattr - prepare to change a possibly-encrypted inode's attributes
+ * @dentry: dentry through which the inode is being changed
+ * @attr: attributes to change
+ *
+ * Prepare for ->setattr() on a possibly-encrypted inode. On an encrypted file,
+ * most attribute changes are allowed even without the encryption key. However,
+ * without the encryption key we do have to forbid truncates. This is needed
+ * because the size being truncated to may not be a multiple of the filesystem
+ * block size, and in that case we'd have to decrypt the final block, zero the
+ * portion past i_size, and re-encrypt it. (We *could* allow truncating to a
+ * filesystem block boundary, but it's simpler to just forbid all truncates ---
+ * and we already forbid all other contents modifications without the key.)
+ *
+ * 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_prepare_setattr(struct dentry *dentry,
+ struct iattr *attr)
+{
+ if (attr->ia_valid & ATTR_SIZE)
+ return fscrypt_require_key(d_inode(dentry));
+ return 0;
+}
+
+#endif /* _LINUX_FSCRYPT_H */
diff --git a/include/linux/fscrypt_common.h b/include/linux/fscrypt_common.h
deleted file mode 100644
index 854d724978fa..000000000000
--- a/include/linux/fscrypt_common.h
+++ /dev/null
@@ -1,142 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * fscrypt_common.h: common declarations for per-file encryption
- *
- * Copyright (C) 2015, Google, Inc.
- *
- * Written by Michael Halcrow, 2015.
- * Modified by Jaegeuk Kim, 2015.
- */
-
-#ifndef _LINUX_FSCRYPT_COMMON_H
-#define _LINUX_FSCRYPT_COMMON_H
-
-#include <linux/key.h>
-#include <linux/fs.h>
-#include <linux/mm.h>
-#include <linux/bio.h>
-#include <linux/dcache.h>
-#include <crypto/skcipher.h>
-#include <uapi/linux/fs.h>
-
-#define FS_CRYPTO_BLOCK_SIZE 16
-
-struct fscrypt_info;
-
-struct fscrypt_ctx {
- union {
- struct {
- struct page *bounce_page; /* Ciphertext page */
- struct page *control_page; /* Original page */
- } w;
- struct {
- struct bio *bio;
- struct work_struct work;
- } r;
- struct list_head free_list; /* Free list */
- };
- u8 flags; /* Flags */
-};
-
-/**
- * For encrypted symlinks, the ciphertext length is stored at the beginning
- * of the string in little-endian format.
- */
-struct fscrypt_symlink_data {
- __le16 len;
- char encrypted_path[1];
-} __packed;
-
-struct fscrypt_str {
- unsigned char *name;
- u32 len;
-};
-
-struct fscrypt_name {
- const struct qstr *usr_fname;
- struct fscrypt_str disk_name;
- u32 hash;
- u32 minor_hash;
- struct fscrypt_str crypto_buf;
-};
-
-#define FSTR_INIT(n, l) { .name = n, .len = l }
-#define FSTR_TO_QSTR(f) QSTR_INIT((f)->name, (f)->len)
-#define fname_name(p) ((p)->disk_name.name)
-#define fname_len(p) ((p)->disk_name.len)
-
-/*
- * fscrypt superblock flags
- */
-#define FS_CFLG_OWN_PAGES (1U << 1)
-
-/*
- * crypto opertions for filesystems
- */
-struct fscrypt_operations {
- unsigned int flags;
- const char *key_prefix;
- int (*get_context)(struct inode *, void *, size_t);
- int (*set_context)(struct inode *, const void *, size_t, void *);
- bool (*dummy_context)(struct inode *);
- bool (*is_encrypted)(struct inode *);
- bool (*empty_dir)(struct inode *);
- unsigned (*max_namelen)(struct inode *);
-};
-
-/* Maximum value for the third parameter of fscrypt_operations.set_context(). */
-#define FSCRYPT_SET_CONTEXT_MAX_SIZE 28
-
-static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
-{
- if (inode->i_sb->s_cop->dummy_context &&
- inode->i_sb->s_cop->dummy_context(inode))
- return true;
- return false;
-}
-
-static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
- u32 filenames_mode)
-{
- if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
- filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
- return true;
-
- if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
- filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
- return true;
-
- return false;
-}
-
-static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
-{
- if (str->len == 1 && str->name[0] == '.')
- return true;
-
- if (str->len == 2 && str->name[0] == '.' && str->name[1] == '.')
- return true;
-
- return false;
-}
-
-static inline struct page *fscrypt_control_page(struct page *page)
-{
-#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
- return ((struct fscrypt_ctx *)page_private(page))->w.control_page;
-#else
- WARN_ON_ONCE(1);
- return ERR_PTR(-EINVAL);
-#endif
-}
-
-static inline int fscrypt_has_encryption_key(const struct inode *inode)
-{
-#if IS_ENABLED(CONFIG_FS_ENCRYPTION)
- return (inode->i_crypt_info != NULL);
-#else
- return 0;
-#endif
-}
-
-#endif /* _LINUX_FSCRYPT_COMMON_H */
diff --git a/include/linux/fscrypt_notsupp.h b/include/linux/fscrypt_notsupp.h
index 19609ceea350..63e58808519a 100644
--- a/include/linux/fscrypt_notsupp.h
+++ b/include/linux/fscrypt_notsupp.h
@@ -4,13 +4,16 @@
*
* This stubs out the fscrypt functions for filesystems configured without
* encryption support.
+ *
+ * Do not include this file directly. Use fscrypt.h instead!
*/
+#ifndef _LINUX_FSCRYPT_H
+#error "Incorrect include of linux/fscrypt_notsupp.h!"
+#endif
#ifndef _LINUX_FSCRYPT_NOTSUPP_H
#define _LINUX_FSCRYPT_NOTSUPP_H
-#include <linux/fscrypt_common.h>
-
/* crypto.c */
static inline struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *inode,
gfp_t gfp_flags)
@@ -98,7 +101,7 @@ static inline int fscrypt_setup_filename(struct inode *dir,
const struct qstr *iname,
int lookup, struct fscrypt_name *fname)
{
- if (dir->i_sb->s_cop->is_encrypted(dir))
+ if (IS_ENCRYPTED(dir))
return -EOPNOTSUPP;
memset(fname, 0, sizeof(struct fscrypt_name));
@@ -175,4 +178,34 @@ static inline int fscrypt_zeroout_range(const struct inode *inode, pgoff_t lblk,
return -EOPNOTSUPP;
}
+/* hooks.c */
+
+static inline int fscrypt_file_open(struct inode *inode, struct file *filp)
+{
+ if (IS_ENCRYPTED(inode))
+ return -EOPNOTSUPP;
+ return 0;
+}
+
+static inline int __fscrypt_prepare_link(struct inode *inode,
+ struct inode *dir)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int __fscrypt_prepare_rename(struct inode *old_dir,
+ struct dentry *old_dentry,
+ struct inode *new_dir,
+ struct dentry *new_dentry,
+ unsigned int flags)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int __fscrypt_prepare_lookup(struct inode *dir,
+ struct dentry *dentry)
+{
+ return -EOPNOTSUPP;
+}
+
#endif /* _LINUX_FSCRYPT_NOTSUPP_H */
diff --git a/include/linux/fscrypt_supp.h b/include/linux/fscrypt_supp.h
index 5153dce22f09..cf9e9fc02f0a 100644
--- a/include/linux/fscrypt_supp.h
+++ b/include/linux/fscrypt_supp.h
@@ -2,14 +2,15 @@
/*
* fscrypt_supp.h
*
- * This is included by filesystems configured with encryption support.
+ * Do not include this file directly. Use fscrypt.h instead!
*/
+#ifndef _LINUX_FSCRYPT_H
+#error "Incorrect include of linux/fscrypt_supp.h!"
+#endif
#ifndef _LINUX_FSCRYPT_SUPP_H
#define _LINUX_FSCRYPT_SUPP_H
-#include <linux/fscrypt_common.h>
-
/* crypto.c */
extern struct kmem_cache *fscrypt_info_cachep;
extern struct fscrypt_ctx *fscrypt_get_ctx(const struct inode *, gfp_t);
@@ -143,4 +144,14 @@ extern void fscrypt_pullback_bio_page(struct page **, bool);
extern int fscrypt_zeroout_range(const struct inode *, pgoff_t, sector_t,
unsigned int);
+/* hooks.c */
+extern int fscrypt_file_open(struct inode *inode, struct file *filp);
+extern int __fscrypt_prepare_link(struct inode *inode, struct inode *dir);
+extern int __fscrypt_prepare_rename(struct inode *old_dir,
+ struct dentry *old_dentry,
+ struct inode *new_dir,
+ struct dentry *new_dentry,
+ unsigned int flags);
+extern int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry);
+
#endif /* _LINUX_FSCRYPT_SUPP_H */