Commit b7e7cf7a authored by Daniel Walter's avatar Daniel Walter Committed by Theodore Ts'o

fscrypt: add support for AES-128-CBC

fscrypt provides facilities to use different encryption algorithms which
are selectable by userspace when setting the encryption policy. Currently,
only AES-256-XTS for file contents and AES-256-CBC-CTS for file names are
implemented. This is a clear case of kernel offers the mechanism and
userspace selects a policy. Similar to what dm-crypt and ecryptfs have.

This patch adds support for using AES-128-CBC for file contents and
AES-128-CBC-CTS for file name encryption. To mitigate watermarking
attacks, IVs are generated using the ESSIV algorithm. While AES-CBC is
actually slightly less secure than AES-XTS from a security point of view,
there is more widespread hardware support. Using AES-CBC gives us the
acceptable performance while still providing a moderate level of security
for persistent storage.

Especially low-powered embedded devices with crypto accelerators such as
CAAM or CESA often only support AES-CBC. Since using AES-CBC over AES-XTS
is basically thought of a last resort, we use AES-128-CBC over AES-256-CBC
since it has less encryption rounds and yields noticeable better
performance starting from a file size of just a few kB.
Signed-off-by: default avatarDaniel Walter <dwalter@sigma-star.at>
[david@sigma-star.at: addressed review comments]
Signed-off-by: default avatarDavid Gstir <david@sigma-star.at>
Reviewed-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 27e47a63
...@@ -7,6 +7,7 @@ config FS_ENCRYPTION ...@@ -7,6 +7,7 @@ config FS_ENCRYPTION
select CRYPTO_XTS select CRYPTO_XTS
select CRYPTO_CTS select CRYPTO_CTS
select CRYPTO_CTR select CRYPTO_CTR
select CRYPTO_SHA256
select KEYS select KEYS
help help
Enable encryption of files and directories. This Enable encryption of files and directories. This
......
...@@ -26,6 +26,7 @@ ...@@ -26,6 +26,7 @@
#include <linux/ratelimit.h> #include <linux/ratelimit.h>
#include <linux/dcache.h> #include <linux/dcache.h>
#include <linux/namei.h> #include <linux/namei.h>
#include <crypto/aes.h>
#include "fscrypt_private.h" #include "fscrypt_private.h"
static unsigned int num_prealloc_crypto_pages = 32; static unsigned int num_prealloc_crypto_pages = 32;
...@@ -147,8 +148,8 @@ int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw, ...@@ -147,8 +148,8 @@ int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
{ {
struct { struct {
__le64 index; __le64 index;
u8 padding[FS_XTS_TWEAK_SIZE - sizeof(__le64)]; u8 padding[FS_IV_SIZE - sizeof(__le64)];
} xts_tweak; } iv;
struct skcipher_request *req = NULL; struct skcipher_request *req = NULL;
DECLARE_FS_COMPLETION_RESULT(ecr); DECLARE_FS_COMPLETION_RESULT(ecr);
struct scatterlist dst, src; struct scatterlist dst, src;
...@@ -158,6 +159,16 @@ int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw, ...@@ -158,6 +159,16 @@ int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
BUG_ON(len == 0); BUG_ON(len == 0);
BUILD_BUG_ON(sizeof(iv) != FS_IV_SIZE);
BUILD_BUG_ON(AES_BLOCK_SIZE != FS_IV_SIZE);
iv.index = cpu_to_le64(lblk_num);
memset(iv.padding, 0, sizeof(iv.padding));
if (ci->ci_essiv_tfm != NULL) {
crypto_cipher_encrypt_one(ci->ci_essiv_tfm, (u8 *)&iv,
(u8 *)&iv);
}
req = skcipher_request_alloc(tfm, gfp_flags); req = skcipher_request_alloc(tfm, gfp_flags);
if (!req) { if (!req) {
printk_ratelimited(KERN_ERR printk_ratelimited(KERN_ERR
...@@ -170,15 +181,11 @@ int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw, ...@@ -170,15 +181,11 @@ int fscrypt_do_page_crypto(const struct inode *inode, fscrypt_direction_t rw,
req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
page_crypt_complete, &ecr); page_crypt_complete, &ecr);
BUILD_BUG_ON(sizeof(xts_tweak) != FS_XTS_TWEAK_SIZE);
xts_tweak.index = cpu_to_le64(lblk_num);
memset(xts_tweak.padding, 0, sizeof(xts_tweak.padding));
sg_init_table(&dst, 1); sg_init_table(&dst, 1);
sg_set_page(&dst, dest_page, len, offs); sg_set_page(&dst, dest_page, len, offs);
sg_init_table(&src, 1); sg_init_table(&src, 1);
sg_set_page(&src, src_page, len, offs); sg_set_page(&src, src_page, len, offs);
skcipher_request_set_crypt(req, &src, &dst, len, &xts_tweak); skcipher_request_set_crypt(req, &src, &dst, len, &iv);
if (rw == FS_DECRYPT) if (rw == FS_DECRYPT)
res = crypto_skcipher_decrypt(req); res = crypto_skcipher_decrypt(req);
else else
...@@ -477,6 +484,8 @@ static void __exit fscrypt_exit(void) ...@@ -477,6 +484,8 @@ static void __exit fscrypt_exit(void)
destroy_workqueue(fscrypt_read_workqueue); destroy_workqueue(fscrypt_read_workqueue);
kmem_cache_destroy(fscrypt_ctx_cachep); kmem_cache_destroy(fscrypt_ctx_cachep);
kmem_cache_destroy(fscrypt_info_cachep); kmem_cache_destroy(fscrypt_info_cachep);
fscrypt_essiv_cleanup();
} }
module_exit(fscrypt_exit); module_exit(fscrypt_exit);
......
...@@ -12,10 +12,13 @@ ...@@ -12,10 +12,13 @@
#define _FSCRYPT_PRIVATE_H #define _FSCRYPT_PRIVATE_H
#include <linux/fscrypt_supp.h> #include <linux/fscrypt_supp.h>
#include <crypto/hash.h>
/* Encryption parameters */ /* Encryption parameters */
#define FS_XTS_TWEAK_SIZE 16 #define FS_IV_SIZE 16
#define FS_AES_128_ECB_KEY_SIZE 16 #define FS_AES_128_ECB_KEY_SIZE 16
#define FS_AES_128_CBC_KEY_SIZE 16
#define FS_AES_128_CTS_KEY_SIZE 16
#define FS_AES_256_GCM_KEY_SIZE 32 #define FS_AES_256_GCM_KEY_SIZE 32
#define FS_AES_256_CBC_KEY_SIZE 32 #define FS_AES_256_CBC_KEY_SIZE 32
#define FS_AES_256_CTS_KEY_SIZE 32 #define FS_AES_256_CTS_KEY_SIZE 32
...@@ -54,6 +57,7 @@ struct fscrypt_info { ...@@ -54,6 +57,7 @@ struct fscrypt_info {
u8 ci_filename_mode; u8 ci_filename_mode;
u8 ci_flags; u8 ci_flags;
struct crypto_skcipher *ci_ctfm; struct crypto_skcipher *ci_ctfm;
struct crypto_cipher *ci_essiv_tfm;
u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE]; u8 ci_master_key[FS_KEY_DESCRIPTOR_SIZE];
}; };
...@@ -87,4 +91,7 @@ extern int fscrypt_do_page_crypto(const struct inode *inode, ...@@ -87,4 +91,7 @@ extern int fscrypt_do_page_crypto(const struct inode *inode,
extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx, extern struct page *fscrypt_alloc_bounce_page(struct fscrypt_ctx *ctx,
gfp_t gfp_flags); gfp_t gfp_flags);
/* keyinfo.c */
extern void __exit fscrypt_essiv_cleanup(void);
#endif /* _FSCRYPT_PRIVATE_H */ #endif /* _FSCRYPT_PRIVATE_H */
...@@ -10,8 +10,13 @@ ...@@ -10,8 +10,13 @@
#include <keys/user-type.h> #include <keys/user-type.h>
#include <linux/scatterlist.h> #include <linux/scatterlist.h>
#include <linux/ratelimit.h>
#include <crypto/aes.h>
#include <crypto/sha.h>
#include "fscrypt_private.h" #include "fscrypt_private.h"
static struct crypto_shash *essiv_hash_tfm;
static void derive_crypt_complete(struct crypto_async_request *req, int rc) static void derive_crypt_complete(struct crypto_async_request *req, int rc)
{ {
struct fscrypt_completion_result *ecr = req->data; struct fscrypt_completion_result *ecr = req->data;
...@@ -27,13 +32,13 @@ static void derive_crypt_complete(struct crypto_async_request *req, int rc) ...@@ -27,13 +32,13 @@ static void derive_crypt_complete(struct crypto_async_request *req, int rc)
* derive_key_aes() - Derive a key using AES-128-ECB * derive_key_aes() - Derive a key using AES-128-ECB
* @deriving_key: Encryption key used for derivation. * @deriving_key: Encryption key used for derivation.
* @source_key: Source key to which to apply derivation. * @source_key: Source key to which to apply derivation.
* @derived_key: Derived key. * @derived_raw_key: Derived raw key.
* *
* Return: Zero on success; non-zero otherwise. * Return: Zero on success; non-zero otherwise.
*/ */
static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE], static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
u8 source_key[FS_AES_256_XTS_KEY_SIZE], const struct fscrypt_key *source_key,
u8 derived_key[FS_AES_256_XTS_KEY_SIZE]) u8 derived_raw_key[FS_MAX_KEY_SIZE])
{ {
int res = 0; int res = 0;
struct skcipher_request *req = NULL; struct skcipher_request *req = NULL;
...@@ -60,10 +65,10 @@ static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE], ...@@ -60,10 +65,10 @@ static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
if (res < 0) if (res < 0)
goto out; goto out;
sg_init_one(&src_sg, source_key, FS_AES_256_XTS_KEY_SIZE); sg_init_one(&src_sg, source_key->raw, source_key->size);
sg_init_one(&dst_sg, derived_key, FS_AES_256_XTS_KEY_SIZE); sg_init_one(&dst_sg, derived_raw_key, source_key->size);
skcipher_request_set_crypt(req, &src_sg, &dst_sg, skcipher_request_set_crypt(req, &src_sg, &dst_sg, source_key->size,
FS_AES_256_XTS_KEY_SIZE, NULL); NULL);
res = crypto_skcipher_encrypt(req); res = crypto_skcipher_encrypt(req);
if (res == -EINPROGRESS || res == -EBUSY) { if (res == -EINPROGRESS || res == -EBUSY) {
wait_for_completion(&ecr.completion); wait_for_completion(&ecr.completion);
...@@ -77,7 +82,7 @@ static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE], ...@@ -77,7 +82,7 @@ static int derive_key_aes(u8 deriving_key[FS_AES_128_ECB_KEY_SIZE],
static int validate_user_key(struct fscrypt_info *crypt_info, static int validate_user_key(struct fscrypt_info *crypt_info,
struct fscrypt_context *ctx, u8 *raw_key, struct fscrypt_context *ctx, u8 *raw_key,
const char *prefix) const char *prefix, int min_keysize)
{ {
char *description; char *description;
struct key *keyring_key; struct key *keyring_key;
...@@ -111,50 +116,60 @@ static int validate_user_key(struct fscrypt_info *crypt_info, ...@@ -111,50 +116,60 @@ static int validate_user_key(struct fscrypt_info *crypt_info,
master_key = (struct fscrypt_key *)ukp->data; master_key = (struct fscrypt_key *)ukp->data;
BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE); BUILD_BUG_ON(FS_AES_128_ECB_KEY_SIZE != FS_KEY_DERIVATION_NONCE_SIZE);
if (master_key->size != FS_AES_256_XTS_KEY_SIZE) { if (master_key->size < min_keysize || master_key->size > FS_MAX_KEY_SIZE
|| master_key->size % AES_BLOCK_SIZE != 0) {
printk_once(KERN_WARNING printk_once(KERN_WARNING
"%s: key size incorrect: %d\n", "%s: key size incorrect: %d\n",
__func__, master_key->size); __func__, master_key->size);
res = -ENOKEY; res = -ENOKEY;
goto out; goto out;
} }
res = derive_key_aes(ctx->nonce, master_key->raw, raw_key); res = derive_key_aes(ctx->nonce, master_key, raw_key);
out: out:
up_read(&keyring_key->sem); up_read(&keyring_key->sem);
key_put(keyring_key); key_put(keyring_key);
return res; return res;
} }
static const struct {
const char *cipher_str;
int keysize;
} available_modes[] = {
[FS_ENCRYPTION_MODE_AES_256_XTS] = { "xts(aes)",
FS_AES_256_XTS_KEY_SIZE },
[FS_ENCRYPTION_MODE_AES_256_CTS] = { "cts(cbc(aes))",
FS_AES_256_CTS_KEY_SIZE },
[FS_ENCRYPTION_MODE_AES_128_CBC] = { "cbc(aes)",
FS_AES_128_CBC_KEY_SIZE },
[FS_ENCRYPTION_MODE_AES_128_CTS] = { "cts(cbc(aes))",
FS_AES_128_CTS_KEY_SIZE },
};
static int determine_cipher_type(struct fscrypt_info *ci, struct inode *inode, static int determine_cipher_type(struct fscrypt_info *ci, struct inode *inode,
const char **cipher_str_ret, int *keysize_ret) const char **cipher_str_ret, int *keysize_ret)
{ {
if (S_ISREG(inode->i_mode)) { u32 mode;
if (ci->ci_data_mode == FS_ENCRYPTION_MODE_AES_256_XTS) {
*cipher_str_ret = "xts(aes)"; if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) {
*keysize_ret = FS_AES_256_XTS_KEY_SIZE; pr_warn_ratelimited("fscrypt: inode %lu uses unsupported encryption modes (contents mode %d, filenames mode %d)\n",
return 0; inode->i_ino,
} ci->ci_data_mode, ci->ci_filename_mode);
pr_warn_once("fscrypto: unsupported contents encryption mode " return -EINVAL;
"%d for inode %lu\n",
ci->ci_data_mode, inode->i_ino);
return -ENOKEY;
} }
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) { if (S_ISREG(inode->i_mode)) {
if (ci->ci_filename_mode == FS_ENCRYPTION_MODE_AES_256_CTS) { mode = ci->ci_data_mode;
*cipher_str_ret = "cts(cbc(aes))"; } else if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) {
*keysize_ret = FS_AES_256_CTS_KEY_SIZE; mode = ci->ci_filename_mode;
return 0; } else {
} WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
pr_warn_once("fscrypto: unsupported filenames encryption mode " inode->i_ino, (inode->i_mode & S_IFMT));
"%d for inode %lu\n", return -EINVAL;
ci->ci_filename_mode, inode->i_ino);
return -ENOKEY;
} }
pr_warn_once("fscrypto: unsupported file type %d for inode %lu\n", *cipher_str_ret = available_modes[mode].cipher_str;
(inode->i_mode & S_IFMT), inode->i_ino); *keysize_ret = available_modes[mode].keysize;
return -ENOKEY; return 0;
} }
static void put_crypt_info(struct fscrypt_info *ci) static void put_crypt_info(struct fscrypt_info *ci)
...@@ -163,9 +178,76 @@ static void put_crypt_info(struct fscrypt_info *ci) ...@@ -163,9 +178,76 @@ static void put_crypt_info(struct fscrypt_info *ci)
return; return;
crypto_free_skcipher(ci->ci_ctfm); crypto_free_skcipher(ci->ci_ctfm);
crypto_free_cipher(ci->ci_essiv_tfm);
kmem_cache_free(fscrypt_info_cachep, ci); kmem_cache_free(fscrypt_info_cachep, ci);
} }
static int derive_essiv_salt(const u8 *key, int keysize, u8 *salt)
{
struct crypto_shash *tfm = READ_ONCE(essiv_hash_tfm);
/* init hash transform on demand */
if (unlikely(!tfm)) {
struct crypto_shash *prev_tfm;
tfm = crypto_alloc_shash("sha256", 0, 0);
if (IS_ERR(tfm)) {
pr_warn_ratelimited("fscrypt: error allocating SHA-256 transform: %ld\n",
PTR_ERR(tfm));
return PTR_ERR(tfm);
}
prev_tfm = cmpxchg(&essiv_hash_tfm, NULL, tfm);
if (prev_tfm) {
crypto_free_shash(tfm);
tfm = prev_tfm;
}
}
{
SHASH_DESC_ON_STACK(desc, tfm);
desc->tfm = tfm;
desc->flags = 0;
return crypto_shash_digest(desc, key, keysize, salt);
}
}
static int init_essiv_generator(struct fscrypt_info *ci, const u8 *raw_key,
int keysize)
{
int err;
struct crypto_cipher *essiv_tfm;
u8 salt[SHA256_DIGEST_SIZE];
essiv_tfm = crypto_alloc_cipher("aes", 0, 0);
if (IS_ERR(essiv_tfm))
return PTR_ERR(essiv_tfm);
ci->ci_essiv_tfm = essiv_tfm;
err = derive_essiv_salt(raw_key, keysize, salt);
if (err)
goto out;
/*
* Using SHA256 to derive the salt/key will result in AES-256 being
* used for IV generation. File contents encryption will still use the
* configured keysize (AES-128) nevertheless.
*/
err = crypto_cipher_setkey(essiv_tfm, salt, sizeof(salt));
if (err)
goto out;
out:
memzero_explicit(salt, sizeof(salt));
return err;
}
void __exit fscrypt_essiv_cleanup(void)
{
crypto_free_shash(essiv_hash_tfm);
}
int fscrypt_get_encryption_info(struct inode *inode) int fscrypt_get_encryption_info(struct inode *inode)
{ {
struct fscrypt_info *crypt_info; struct fscrypt_info *crypt_info;
...@@ -212,6 +294,7 @@ int fscrypt_get_encryption_info(struct inode *inode) ...@@ -212,6 +294,7 @@ int fscrypt_get_encryption_info(struct inode *inode)
crypt_info->ci_data_mode = ctx.contents_encryption_mode; crypt_info->ci_data_mode = ctx.contents_encryption_mode;
crypt_info->ci_filename_mode = ctx.filenames_encryption_mode; crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
crypt_info->ci_ctfm = NULL; crypt_info->ci_ctfm = NULL;
crypt_info->ci_essiv_tfm = NULL;
memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor, memcpy(crypt_info->ci_master_key, ctx.master_key_descriptor,
sizeof(crypt_info->ci_master_key)); sizeof(crypt_info->ci_master_key));
...@@ -228,10 +311,12 @@ int fscrypt_get_encryption_info(struct inode *inode) ...@@ -228,10 +311,12 @@ int fscrypt_get_encryption_info(struct inode *inode)
if (!raw_key) if (!raw_key)
goto out; goto out;
res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX); res = validate_user_key(crypt_info, &ctx, raw_key, FS_KEY_DESC_PREFIX,
keysize);
if (res && inode->i_sb->s_cop->key_prefix) { if (res && inode->i_sb->s_cop->key_prefix) {
int res2 = validate_user_key(crypt_info, &ctx, raw_key, int res2 = validate_user_key(crypt_info, &ctx, raw_key,
inode->i_sb->s_cop->key_prefix); inode->i_sb->s_cop->key_prefix,
keysize);
if (res2) { if (res2) {
if (res2 == -ENOKEY) if (res2 == -ENOKEY)
res = -ENOKEY; res = -ENOKEY;
...@@ -243,18 +328,30 @@ int fscrypt_get_encryption_info(struct inode *inode) ...@@ -243,18 +328,30 @@ int fscrypt_get_encryption_info(struct inode *inode)
ctfm = crypto_alloc_skcipher(cipher_str, 0, 0); ctfm = crypto_alloc_skcipher(cipher_str, 0, 0);
if (!ctfm || IS_ERR(ctfm)) { if (!ctfm || IS_ERR(ctfm)) {
res = ctfm ? PTR_ERR(ctfm) : -ENOMEM; res = ctfm ? PTR_ERR(ctfm) : -ENOMEM;
printk(KERN_DEBUG pr_debug("%s: error %d (inode %lu) allocating crypto tfm\n",
"%s: error %d (inode %u) allocating crypto tfm\n", __func__, res, inode->i_ino);
__func__, res, (unsigned) inode->i_ino);
goto out; goto out;
} }
crypt_info->ci_ctfm = ctfm; crypt_info->ci_ctfm = ctfm;
crypto_skcipher_clear_flags(ctfm, ~0); crypto_skcipher_clear_flags(ctfm, ~0);
crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY); crypto_skcipher_set_flags(ctfm, CRYPTO_TFM_REQ_WEAK_KEY);
/*
* if the provided key is longer than keysize, we use the first
* keysize bytes of the derived key only
*/
res = crypto_skcipher_setkey(ctfm, raw_key, keysize); res = crypto_skcipher_setkey(ctfm, raw_key, keysize);
if (res) if (res)
goto out; goto out;
if (S_ISREG(inode->i_mode) &&
crypt_info->ci_data_mode == FS_ENCRYPTION_MODE_AES_128_CBC) {
res = init_essiv_generator(crypt_info, raw_key, keysize);
if (res) {
pr_debug("%s: error %d (inode %lu) allocating essiv tfm\n",
__func__, res, inode->i_ino);
goto out;
}
}
if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) == NULL) if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) == NULL)
crypt_info = NULL; crypt_info = NULL;
out: out:
......
...@@ -38,12 +38,8 @@ static int create_encryption_context_from_policy(struct inode *inode, ...@@ -38,12 +38,8 @@ static int create_encryption_context_from_policy(struct inode *inode,
memcpy(ctx.master_key_descriptor, policy->master_key_descriptor, memcpy(ctx.master_key_descriptor, policy->master_key_descriptor,
FS_KEY_DESCRIPTOR_SIZE); FS_KEY_DESCRIPTOR_SIZE);
if (!fscrypt_valid_contents_enc_mode( if (!fscrypt_valid_enc_modes(policy->contents_encryption_mode,
policy->contents_encryption_mode)) policy->filenames_encryption_mode))
return -EINVAL;
if (!fscrypt_valid_filenames_enc_mode(
policy->filenames_encryption_mode))
return -EINVAL; return -EINVAL;
if (policy->flags & ~FS_POLICY_FLAGS_VALID) if (policy->flags & ~FS_POLICY_FLAGS_VALID)
......
...@@ -91,14 +91,18 @@ static inline bool fscrypt_dummy_context_enabled(struct inode *inode) ...@@ -91,14 +91,18 @@ static inline bool fscrypt_dummy_context_enabled(struct inode *inode)
return false; return false;
} }
static inline bool fscrypt_valid_contents_enc_mode(u32 mode) static inline bool fscrypt_valid_enc_modes(u32 contents_mode,
u32 filenames_mode)
{ {
return (mode == FS_ENCRYPTION_MODE_AES_256_XTS); if (contents_mode == FS_ENCRYPTION_MODE_AES_128_CBC &&
} filenames_mode == FS_ENCRYPTION_MODE_AES_128_CTS)
return true;
static inline bool fscrypt_valid_filenames_enc_mode(u32 mode) if (contents_mode == FS_ENCRYPTION_MODE_AES_256_XTS &&
{ filenames_mode == FS_ENCRYPTION_MODE_AES_256_CTS)
return (mode == FS_ENCRYPTION_MODE_AES_256_CTS); return true;
return false;
} }
static inline bool fscrypt_is_dot_dotdot(const struct qstr *str) static inline bool fscrypt_is_dot_dotdot(const struct qstr *str)
......
...@@ -272,6 +272,8 @@ struct fsxattr { ...@@ -272,6 +272,8 @@ struct fsxattr {
#define FS_ENCRYPTION_MODE_AES_256_GCM 2 #define FS_ENCRYPTION_MODE_AES_256_GCM 2
#define FS_ENCRYPTION_MODE_AES_256_CBC 3 #define FS_ENCRYPTION_MODE_AES_256_CBC 3
#define FS_ENCRYPTION_MODE_AES_256_CTS 4 #define FS_ENCRYPTION_MODE_AES_256_CTS 4
#define FS_ENCRYPTION_MODE_AES_128_CBC 5
#define FS_ENCRYPTION_MODE_AES_128_CTS 6
struct fscrypt_policy { struct fscrypt_policy {
__u8 version; __u8 version;
......
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