From: Eric Biggers <ebiggers@kernel.org>
To: linux-fscrypt@vger.kernel.org
Cc: Satya Tangirala <satyat@google.com>,
Theodore Ts'o <tytso@mit.edu>,
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 <jaegeuk@kernel.org>,
linux-ext4@vger.kernel.org, Paul Crowley <paulcrowley@google.com>
Subject: [PATCH v8 02/20] fscrypt: use FSCRYPT_ prefix for uapi constants
Date: Mon, 5 Aug 2019 09:25:03 -0700 [thread overview]
Message-ID: <20190805162521.90882-3-ebiggers@kernel.org> (raw)
In-Reply-To: <20190805162521.90882-1-ebiggers@kernel.org>
From: Eric Biggers <ebiggers@google.com>
Prefix all filesystem encryption UAPI constants except the ioctl numbers
with "FSCRYPT_" rather than with "FS_". This namespaces the constants
more appropriately and makes it clear that they are related specifically
to the filesystem encryption feature, and to the 'fscrypt_*' structures.
With some of the old names like "FS_POLICY_FLAGS_VALID", it was not
immediately clear that the constant had anything to do with encryption.
This is also useful because we'll be adding more encryption-related
constants, e.g. for the policy version, and we'd otherwise have to
choose whether to use unclear names like FS_POLICY_V1 or inconsistent
names like FS_ENCRYPTION_POLICY_V1.
For source compatibility with existing userspace programs, keep the old
names defined as aliases to the new names.
Finally, as long as new names are being defined anyway, I skipped
defining new names for the fscrypt mode numbers that aren't actually
used: INVALID (0), AES_256_GCM (2), AES_256_CBC (3), SPECK128_256_XTS
(7), and SPECK128_256_CTS (8).
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
Documentation/filesystems/fscrypt.rst | 40 ++++++++---------
include/uapi/linux/fscrypt.h | 65 +++++++++++++++++----------
2 files changed, 62 insertions(+), 43 deletions(-)
diff --git a/Documentation/filesystems/fscrypt.rst b/Documentation/filesystems/fscrypt.rst
index 82efa41b0e6c02..d60b885c402401 100644
--- a/Documentation/filesystems/fscrypt.rst
+++ b/Documentation/filesystems/fscrypt.rst
@@ -225,9 +225,10 @@ a little endian number, except that:
is encrypted with AES-256 where the AES-256 key is the SHA-256 hash
of the file's data encryption key.
-- In the "direct key" configuration (FS_POLICY_FLAG_DIRECT_KEY set in
- the fscrypt_policy), the file's nonce is also appended to the IV.
- Currently this is only allowed with the Adiantum encryption mode.
+- In the "direct key" configuration (FSCRYPT_POLICY_FLAG_DIRECT_KEY
+ set in the fscrypt_policy), the file's nonce is also appended to the
+ IV. Currently this is only allowed with the Adiantum encryption
+ mode.
Filenames encryption
--------------------
@@ -274,14 +275,14 @@ 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
+ #define FSCRYPT_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];
+ __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
};
This structure must be initialized as follows:
@@ -289,19 +290,18 @@ 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``.
+ be set to constants from ``<linux/fscrypt.h>`` which identify the
+ encryption modes to use. If unsure, use FSCRYPT_MODE_AES_256_XTS
+ (1) for ``contents_encryption_mode`` and FSCRYPT_MODE_AES_256_CTS
+ (4) for ``filenames_encryption_mode``.
-- ``flags`` must contain a value from ``<linux/fs.h>`` which
+- ``flags`` must contain a value from ``<linux/fscrypt.h>`` which
identifies the amount of NUL-padding to use when encrypting
- filenames. If unsure, use FS_POLICY_FLAGS_PAD_32 (0x3).
- In addition, if the chosen encryption modes are both
- FS_ENCRYPTION_MODE_ADIANTUM, this can contain
- FS_POLICY_FLAG_DIRECT_KEY to specify that the master key should be
- used directly, without key derivation.
+ filenames. If unsure, use FSCRYPT_POLICY_FLAGS_PAD_32 (0x3). In
+ addition, if the chosen encryption modes are both
+ FSCRYPT_MODE_ADIANTUM, this can contain
+ FSCRYPT_POLICY_FLAG_DIRECT_KEY to specify that the master key should
+ be used directly, without key derivation.
- ``master_key_descriptor`` specifies how to find the master key in
the keyring; see `Adding keys`_. It is up to userspace to choose a
@@ -401,11 +401,11 @@ 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
+ #define FSCRYPT_MAX_KEY_SIZE 64
struct fscrypt_key {
u32 mode;
- u8 raw[FS_MAX_KEY_SIZE];
+ u8 raw[FSCRYPT_MAX_KEY_SIZE];
u32 size;
};
@@ -574,7 +574,7 @@ 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 FSCRYPT_KEY_DESCRIPTOR_SIZE 8
#define FS_KEY_DERIVATION_NONCE_SIZE 16
struct fscrypt_context {
@@ -582,7 +582,7 @@ as follows::
u8 contents_encryption_mode;
u8 filenames_encryption_mode;
u8 flags;
- u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+ u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
u8 nonce[FS_KEY_DERIVATION_NONCE_SIZE];
};
diff --git a/include/uapi/linux/fscrypt.h b/include/uapi/linux/fscrypt.h
index 26f6d2c19afd3f..674b0452ef5759 100644
--- a/include/uapi/linux/fscrypt.h
+++ b/include/uapi/linux/fscrypt.h
@@ -10,35 +10,30 @@
#include <linux/types.h>
-#define FS_KEY_DESCRIPTOR_SIZE 8
+#define FSCRYPT_KEY_DESCRIPTOR_SIZE 8
/* Encryption policy flags */
-#define FS_POLICY_FLAGS_PAD_4 0x00
-#define FS_POLICY_FLAGS_PAD_8 0x01
-#define FS_POLICY_FLAGS_PAD_16 0x02
-#define FS_POLICY_FLAGS_PAD_32 0x03
-#define FS_POLICY_FLAGS_PAD_MASK 0x03
-#define FS_POLICY_FLAG_DIRECT_KEY 0x04 /* use master key directly */
-#define FS_POLICY_FLAGS_VALID 0x07
+#define FSCRYPT_POLICY_FLAGS_PAD_4 0x00
+#define FSCRYPT_POLICY_FLAGS_PAD_8 0x01
+#define FSCRYPT_POLICY_FLAGS_PAD_16 0x02
+#define FSCRYPT_POLICY_FLAGS_PAD_32 0x03
+#define FSCRYPT_POLICY_FLAGS_PAD_MASK 0x03
+#define FSCRYPT_POLICY_FLAG_DIRECT_KEY 0x04 /* use master key directly */
+#define FSCRYPT_POLICY_FLAGS_VALID 0x07
/* Encryption algorithms */
-#define FS_ENCRYPTION_MODE_INVALID 0
-#define FS_ENCRYPTION_MODE_AES_256_XTS 1
-#define FS_ENCRYPTION_MODE_AES_256_GCM 2
-#define FS_ENCRYPTION_MODE_AES_256_CBC 3
-#define FS_ENCRYPTION_MODE_AES_256_CTS 4
-#define FS_ENCRYPTION_MODE_AES_128_CBC 5
-#define FS_ENCRYPTION_MODE_AES_128_CTS 6
-#define FS_ENCRYPTION_MODE_SPECK128_256_XTS 7 /* Removed, do not use. */
-#define FS_ENCRYPTION_MODE_SPECK128_256_CTS 8 /* Removed, do not use. */
-#define FS_ENCRYPTION_MODE_ADIANTUM 9
+#define FSCRYPT_MODE_AES_256_XTS 1
+#define FSCRYPT_MODE_AES_256_CTS 4
+#define FSCRYPT_MODE_AES_128_CBC 5
+#define FSCRYPT_MODE_AES_128_CTS 6
+#define FSCRYPT_MODE_ADIANTUM 9
struct fscrypt_policy {
__u8 version;
__u8 contents_encryption_mode;
__u8 filenames_encryption_mode;
__u8 flags;
- __u8 master_key_descriptor[FS_KEY_DESCRIPTOR_SIZE];
+ __u8 master_key_descriptor[FSCRYPT_KEY_DESCRIPTOR_SIZE];
};
#define FS_IOC_SET_ENCRYPTION_POLICY _IOR('f', 19, struct fscrypt_policy)
@@ -46,16 +41,40 @@ struct fscrypt_policy {
#define FS_IOC_GET_ENCRYPTION_POLICY _IOW('f', 21, struct fscrypt_policy)
/* Parameters for passing an encryption key into the kernel keyring */
-#define FS_KEY_DESC_PREFIX "fscrypt:"
-#define FS_KEY_DESC_PREFIX_SIZE 8
+#define FSCRYPT_KEY_DESC_PREFIX "fscrypt:"
+#define FSCRYPT_KEY_DESC_PREFIX_SIZE 8
/* Structure that userspace passes to the kernel keyring */
-#define FS_MAX_KEY_SIZE 64
+#define FSCRYPT_MAX_KEY_SIZE 64
struct fscrypt_key {
__u32 mode;
- __u8 raw[FS_MAX_KEY_SIZE];
+ __u8 raw[FSCRYPT_MAX_KEY_SIZE];
__u32 size;
};
+/**********************************************************************/
+
+/* old names; don't add anything new here! */
+#define FS_KEY_DESCRIPTOR_SIZE FSCRYPT_KEY_DESCRIPTOR_SIZE
+#define FS_POLICY_FLAGS_PAD_4 FSCRYPT_POLICY_FLAGS_PAD_4
+#define FS_POLICY_FLAGS_PAD_8 FSCRYPT_POLICY_FLAGS_PAD_8
+#define FS_POLICY_FLAGS_PAD_16 FSCRYPT_POLICY_FLAGS_PAD_16
+#define FS_POLICY_FLAGS_PAD_32 FSCRYPT_POLICY_FLAGS_PAD_32
+#define FS_POLICY_FLAGS_PAD_MASK FSCRYPT_POLICY_FLAGS_PAD_MASK
+#define FS_POLICY_FLAG_DIRECT_KEY FSCRYPT_POLICY_FLAG_DIRECT_KEY
+#define FS_POLICY_FLAGS_VALID FSCRYPT_POLICY_FLAGS_VALID
+#define FS_ENCRYPTION_MODE_INVALID 0 /* never used */
+#define FS_ENCRYPTION_MODE_AES_256_XTS FSCRYPT_MODE_AES_256_XTS
+#define FS_ENCRYPTION_MODE_AES_256_GCM 2 /* never used */
+#define FS_ENCRYPTION_MODE_AES_256_CBC 3 /* never used */
+#define FS_ENCRYPTION_MODE_AES_256_CTS FSCRYPT_MODE_AES_256_CTS
+#define FS_ENCRYPTION_MODE_AES_128_CBC FSCRYPT_MODE_AES_128_CBC
+#define FS_ENCRYPTION_MODE_AES_128_CTS FSCRYPT_MODE_AES_128_CTS
+#define FS_ENCRYPTION_MODE_SPECK128_256_XTS 7 /* removed */
+#define FS_ENCRYPTION_MODE_SPECK128_256_CTS 8 /* removed */
+#define FS_ENCRYPTION_MODE_ADIANTUM FSCRYPT_MODE_ADIANTUM
+#define FS_KEY_DESC_PREFIX FSCRYPT_KEY_DESC_PREFIX
+#define FS_KEY_DESC_PREFIX_SIZE FSCRYPT_KEY_DESC_PREFIX_SIZE
+#define FS_MAX_KEY_SIZE FSCRYPT_MAX_KEY_SIZE
#endif /* _UAPI_LINUX_FSCRYPT_H */
--
2.22.0.770.g0f2c4a37fd-goog
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next prev parent reply other threads:[~2019-08-05 16:30 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-05 16:25 [PATCH v8 00/20] fscrypt: key management improvements Eric Biggers
2019-08-05 16:25 ` [PATCH v8 01/20] fs, fscrypt: move uapi definitions to new header <linux/fscrypt.h> Eric Biggers
2019-08-05 16:25 ` Eric Biggers [this message]
2019-08-05 16:25 ` [PATCH v8 03/20] fscrypt: use FSCRYPT_* definitions, not FS_* Eric Biggers
2019-08-05 16:25 ` [PATCH v8 04/20] fscrypt: add ->ci_inode to fscrypt_info Eric Biggers
2019-08-05 16:25 ` [PATCH v8 05/20] fscrypt: rename fscrypt_master_key to fscrypt_direct_key Eric Biggers
2019-08-12 22:20 ` Theodore Y. Ts'o
2019-08-05 16:25 ` [PATCH v8 06/20] fscrypt: refactor key setup code in preparation for v2 policies Eric Biggers
2019-08-12 22:38 ` Theodore Y. Ts'o
2019-08-05 16:25 ` [PATCH v8 07/20] fscrypt: move v1 policy key setup to keysetup_v1.c Eric Biggers
2019-08-12 22:53 ` Theodore Y. Ts'o
2019-08-05 16:25 ` [PATCH v8 08/20] fscrypt: rename keyinfo.c to keysetup.c Eric Biggers
2019-08-12 22:53 ` Theodore Y. Ts'o
2019-08-05 16:25 ` [PATCH v8 09/20] fscrypt: add FS_IOC_ADD_ENCRYPTION_KEY ioctl Eric Biggers
2019-08-05 16:25 ` [PATCH v8 10/20] fscrypt: add FS_IOC_REMOVE_ENCRYPTION_KEY ioctl Eric Biggers
2019-08-13 0:06 ` Theodore Y. Ts'o
2019-08-14 22:35 ` Eric Biggers
2019-08-05 16:25 ` [PATCH v8 11/20] fscrypt: add FS_IOC_GET_ENCRYPTION_KEY_STATUS ioctl Eric Biggers
2019-08-05 16:25 ` [PATCH v8 12/20] fscrypt: add an HKDF-SHA512 implementation Eric Biggers
2019-08-06 20:43 ` Paul Crowley
2019-08-05 16:25 ` [PATCH v8 13/20] fscrypt: v2 encryption policy support Eric Biggers
2019-08-06 20:44 ` Paul Crowley
2019-08-13 0:39 ` Theodore Y. Ts'o
2019-08-05 16:25 ` [PATCH v8 14/20] fscrypt: allow unprivileged users to add/remove keys for v2 policies Eric Biggers
2019-08-13 0:14 ` Theodore Y. Ts'o
2019-08-05 16:25 ` [PATCH v8 15/20] fscrypt: add FS_IOC_REMOVE_ENCRYPTION_KEY_ALL_USERS ioctl Eric Biggers
2019-08-13 0:15 ` Theodore Y. Ts'o
2019-08-05 16:25 ` [PATCH v8 16/20] fscrypt: require that key be added when setting a v2 encryption policy Eric Biggers
2019-08-05 16:25 ` [PATCH v8 17/20] ext4: wire up new fscrypt ioctls Eric Biggers
2019-08-05 16:25 ` [PATCH v8 18/20] f2fs: " Eric Biggers
2019-08-05 16:25 ` [PATCH v8 19/20] ubifs: " Eric Biggers
2019-08-05 16:25 ` [PATCH v8 20/20] fscrypt: document the new ioctls and policy version Eric Biggers
2019-08-13 0:49 ` Theodore Y. Ts'o
2019-08-14 22:37 ` [PATCH v8 00/20] fscrypt: key management improvements Eric Biggers
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