mirror of
https://github.com/torvalds/linux.git
synced 2024-12-30 14:52:05 +00:00
fscrypt: use FSCRYPT_ prefix for uapi constants
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>
This commit is contained in:
Eric Biggers
parent
7af0ab0d3a
commit
2336d0deb2
@ -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];
|
||||
};
|
||||
|
||||
|
||||
@ -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 */
|
||||
|
||||
Loading…
Reference in New Issue
Block a user