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fscrypt: move non-public structures and constants to fscrypt_private.h
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Signed-off-by: Theodore Ts'o <[email protected]>
Reviewed-by: Eric Biggers <[email protected]>
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tytso committed Dec 11, 2016
1 parent b98701d commit cc4e0df
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Showing 4 changed files with 76 additions and 67 deletions.
2 changes: 1 addition & 1 deletion fs/crypto/crypto.c
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Expand Up @@ -27,7 +27,7 @@
#include <linux/bio.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/fscrypto.h>
#include "fscrypt_private.h"

static unsigned int num_prealloc_crypto_pages = 32;
static unsigned int num_prealloc_crypto_ctxs = 128;
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71 changes: 71 additions & 0 deletions fs/crypto/fscrypt_private.h
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Expand Up @@ -13,6 +13,77 @@

#include <linux/fscrypto.h>

#define FS_FNAME_CRYPTO_DIGEST_SIZE 32

/* Encryption parameters */
#define FS_XTS_TWEAK_SIZE 16
#define FS_AES_128_ECB_KEY_SIZE 16
#define FS_AES_256_GCM_KEY_SIZE 32
#define FS_AES_256_CBC_KEY_SIZE 32
#define FS_AES_256_CTS_KEY_SIZE 32
#define FS_AES_256_XTS_KEY_SIZE 64
#define FS_MAX_KEY_SIZE 64

#define FS_KEY_DESC_PREFIX "fscrypt:"
#define FS_KEY_DESC_PREFIX_SIZE 8

#define FS_KEY_DERIVATION_NONCE_SIZE 16

/**
* Encryption context for inode
*
* Protector format:
* 1 byte: Protector format (1 = this version)
* 1 byte: File contents encryption mode
* 1 byte: File names encryption mode
* 1 byte: Flags
* 8 bytes: Master Key descriptor
* 16 bytes: Encryption Key derivation nonce
*/
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];
} __packed;

#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1

/* This is passed in from userspace into the kernel keyring */
struct fscrypt_key {
u32 mode;
u8 raw[FS_MAX_KEY_SIZE];
u32 size;
} __packed;

/*
* A pointer to this structure is stored in the file system's in-core
* representation of an inode.
*/
struct fscrypt_info {
u8 ci_data_mode;
u8 ci_filename_mode;
u8 ci_flags;
struct crypto_skcipher *ci_ctfm;
struct key *ci_keyring_key;
u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
};

#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
#define FS_WRITE_PATH_FL 0x00000002

struct fscrypt_completion_result {
struct completion completion;
int res;
};

#define DECLARE_FS_COMPLETION_RESULT(ecr) \
struct fscrypt_completion_result ecr = { \
COMPLETION_INITIALIZER((ecr).completion), 0 }


/* crypto.c */
int fscrypt_initialize(void);

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2 changes: 1 addition & 1 deletion fs/crypto/policy.c
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Expand Up @@ -10,8 +10,8 @@

#include <linux/random.h>
#include <linux/string.h>
#include <linux/fscrypto.h>
#include <linux/mount.h>
#include "fscrypt_private.h"

static int inode_has_encryption_context(struct inode *inode)
{
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68 changes: 3 additions & 65 deletions include/linux/fscrypto.h
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Expand Up @@ -18,9 +18,6 @@
#include <crypto/skcipher.h>
#include <uapi/linux/fs.h>

#define FS_KEY_DERIVATION_NONCE_SIZE 16
#define FS_ENCRYPTION_CONTEXT_FORMAT_V1 1

#define FS_POLICY_FLAGS_PAD_4 0x00
#define FS_POLICY_FLAGS_PAD_8 0x01
#define FS_POLICY_FLAGS_PAD_16 0x02
Expand All @@ -35,56 +32,10 @@
#define FS_ENCRYPTION_MODE_AES_256_CBC 3
#define FS_ENCRYPTION_MODE_AES_256_CTS 4

/**
* Encryption context for inode
*
* Protector format:
* 1 byte: Protector format (1 = this version)
* 1 byte: File contents encryption mode
* 1 byte: File names encryption mode
* 1 byte: Flags
* 8 bytes: Master Key descriptor
* 16 bytes: Encryption Key derivation nonce
*/
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];
} __packed;

/* Encryption parameters */
#define FS_XTS_TWEAK_SIZE 16
#define FS_AES_128_ECB_KEY_SIZE 16
#define FS_AES_256_GCM_KEY_SIZE 32
#define FS_AES_256_CBC_KEY_SIZE 32
#define FS_AES_256_CTS_KEY_SIZE 32
#define FS_AES_256_XTS_KEY_SIZE 64
#define FS_MAX_KEY_SIZE 64

#define FS_KEY_DESC_PREFIX "fscrypt:"
#define FS_KEY_DESC_PREFIX_SIZE 8

/* This is passed in from userspace into the kernel keyring */
struct fscrypt_key {
u32 mode;
u8 raw[FS_MAX_KEY_SIZE];
u32 size;
} __packed;

struct fscrypt_info {
u8 ci_data_mode;
u8 ci_filename_mode;
u8 ci_flags;
struct crypto_skcipher *ci_ctfm;
struct key *ci_keyring_key;
u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
};
#define FS_CRYPTO_BLOCK_SIZE 16

#define FS_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
#define FS_WRITE_PATH_FL 0x00000002
struct fscrypt_info;
struct fscrypt_ctx;

struct fscrypt_ctx {
union {
Expand All @@ -102,19 +53,6 @@ struct fscrypt_ctx {
u8 mode; /* Encryption mode for tfm */
};

struct fscrypt_completion_result {
struct completion completion;
int res;
};

#define DECLARE_FS_COMPLETION_RESULT(ecr) \
struct fscrypt_completion_result ecr = { \
COMPLETION_INITIALIZER((ecr).completion), 0 }

#define FS_FNAME_NUM_SCATTER_ENTRIES 4
#define FS_CRYPTO_BLOCK_SIZE 16
#define FS_FNAME_CRYPTO_DIGEST_SIZE 32

/**
* For encrypted symlinks, the ciphertext length is stored at the beginning
* of the string in little-endian format.
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