mirror of
https://github.com/torvalds/linux.git
synced 2024-11-20 11:01:38 +00:00
877b5691f2
The flags field in 'struct shash_desc' never actually does anything. The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP. However, no shash algorithm ever sleeps, making this flag a no-op. With this being the case, inevitably some users who can't sleep wrongly pass MAY_SLEEP. These would all need to be fixed if any shash algorithm actually started sleeping. For example, the shash_ahash_*() functions, which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP from the ahash API to the shash API. However, the shash functions are called under kmap_atomic(), so actually they're assumed to never sleep. Even if it turns out that some users do need preemption points while hashing large buffers, we could easily provide a helper function crypto_shash_update_large() which divides the data into smaller chunks and calls crypto_shash_update() and cond_resched() for each chunk. It's not necessary to have a flag in 'struct shash_desc', nor is it necessary to make individual shash algorithms aware of this at all. Therefore, remove shash_desc::flags, and document that the crypto_shash_*() functions can be called from any context. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
592 lines
16 KiB
C
592 lines
16 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* key management facility for FS encryption support.
|
|
*
|
|
* Copyright (C) 2015, Google, Inc.
|
|
*
|
|
* This contains encryption key functions.
|
|
*
|
|
* Written by Michael Halcrow, Ildar Muslukhov, and Uday Savagaonkar, 2015.
|
|
*/
|
|
|
|
#include <keys/user-type.h>
|
|
#include <linux/hashtable.h>
|
|
#include <linux/scatterlist.h>
|
|
#include <linux/ratelimit.h>
|
|
#include <crypto/aes.h>
|
|
#include <crypto/algapi.h>
|
|
#include <crypto/sha.h>
|
|
#include <crypto/skcipher.h>
|
|
#include "fscrypt_private.h"
|
|
|
|
static struct crypto_shash *essiv_hash_tfm;
|
|
|
|
/* Table of keys referenced by FS_POLICY_FLAG_DIRECT_KEY policies */
|
|
static DEFINE_HASHTABLE(fscrypt_master_keys, 6); /* 6 bits = 64 buckets */
|
|
static DEFINE_SPINLOCK(fscrypt_master_keys_lock);
|
|
|
|
/*
|
|
* Key derivation function. This generates the derived key by encrypting the
|
|
* master key with AES-128-ECB using the inode's nonce as the AES key.
|
|
*
|
|
* The master key must be at least as long as the derived key. If the master
|
|
* key is longer, then only the first 'derived_keysize' bytes are used.
|
|
*/
|
|
static int derive_key_aes(const u8 *master_key,
|
|
const struct fscrypt_context *ctx,
|
|
u8 *derived_key, unsigned int derived_keysize)
|
|
{
|
|
int res = 0;
|
|
struct skcipher_request *req = NULL;
|
|
DECLARE_CRYPTO_WAIT(wait);
|
|
struct scatterlist src_sg, dst_sg;
|
|
struct crypto_skcipher *tfm = crypto_alloc_skcipher("ecb(aes)", 0, 0);
|
|
|
|
if (IS_ERR(tfm)) {
|
|
res = PTR_ERR(tfm);
|
|
tfm = NULL;
|
|
goto out;
|
|
}
|
|
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
|
|
req = skcipher_request_alloc(tfm, GFP_NOFS);
|
|
if (!req) {
|
|
res = -ENOMEM;
|
|
goto out;
|
|
}
|
|
skcipher_request_set_callback(req,
|
|
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
|
|
crypto_req_done, &wait);
|
|
res = crypto_skcipher_setkey(tfm, ctx->nonce, sizeof(ctx->nonce));
|
|
if (res < 0)
|
|
goto out;
|
|
|
|
sg_init_one(&src_sg, master_key, derived_keysize);
|
|
sg_init_one(&dst_sg, derived_key, derived_keysize);
|
|
skcipher_request_set_crypt(req, &src_sg, &dst_sg, derived_keysize,
|
|
NULL);
|
|
res = crypto_wait_req(crypto_skcipher_encrypt(req), &wait);
|
|
out:
|
|
skcipher_request_free(req);
|
|
crypto_free_skcipher(tfm);
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
* Search the current task's subscribed keyrings for a "logon" key with
|
|
* description prefix:descriptor, and if found acquire a read lock on it and
|
|
* return a pointer to its validated payload in *payload_ret.
|
|
*/
|
|
static struct key *
|
|
find_and_lock_process_key(const char *prefix,
|
|
const u8 descriptor[FS_KEY_DESCRIPTOR_SIZE],
|
|
unsigned int min_keysize,
|
|
const struct fscrypt_key **payload_ret)
|
|
{
|
|
char *description;
|
|
struct key *key;
|
|
const struct user_key_payload *ukp;
|
|
const struct fscrypt_key *payload;
|
|
|
|
description = kasprintf(GFP_NOFS, "%s%*phN", prefix,
|
|
FS_KEY_DESCRIPTOR_SIZE, descriptor);
|
|
if (!description)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
key = request_key(&key_type_logon, description, NULL);
|
|
kfree(description);
|
|
if (IS_ERR(key))
|
|
return key;
|
|
|
|
down_read(&key->sem);
|
|
ukp = user_key_payload_locked(key);
|
|
|
|
if (!ukp) /* was the key revoked before we acquired its semaphore? */
|
|
goto invalid;
|
|
|
|
payload = (const struct fscrypt_key *)ukp->data;
|
|
|
|
if (ukp->datalen != sizeof(struct fscrypt_key) ||
|
|
payload->size < 1 || payload->size > FS_MAX_KEY_SIZE) {
|
|
fscrypt_warn(NULL,
|
|
"key with description '%s' has invalid payload",
|
|
key->description);
|
|
goto invalid;
|
|
}
|
|
|
|
if (payload->size < min_keysize) {
|
|
fscrypt_warn(NULL,
|
|
"key with description '%s' is too short (got %u bytes, need %u+ bytes)",
|
|
key->description, payload->size, min_keysize);
|
|
goto invalid;
|
|
}
|
|
|
|
*payload_ret = payload;
|
|
return key;
|
|
|
|
invalid:
|
|
up_read(&key->sem);
|
|
key_put(key);
|
|
return ERR_PTR(-ENOKEY);
|
|
}
|
|
|
|
static struct fscrypt_mode available_modes[] = {
|
|
[FS_ENCRYPTION_MODE_AES_256_XTS] = {
|
|
.friendly_name = "AES-256-XTS",
|
|
.cipher_str = "xts(aes)",
|
|
.keysize = 64,
|
|
.ivsize = 16,
|
|
},
|
|
[FS_ENCRYPTION_MODE_AES_256_CTS] = {
|
|
.friendly_name = "AES-256-CTS-CBC",
|
|
.cipher_str = "cts(cbc(aes))",
|
|
.keysize = 32,
|
|
.ivsize = 16,
|
|
},
|
|
[FS_ENCRYPTION_MODE_AES_128_CBC] = {
|
|
.friendly_name = "AES-128-CBC",
|
|
.cipher_str = "cbc(aes)",
|
|
.keysize = 16,
|
|
.ivsize = 16,
|
|
.needs_essiv = true,
|
|
},
|
|
[FS_ENCRYPTION_MODE_AES_128_CTS] = {
|
|
.friendly_name = "AES-128-CTS-CBC",
|
|
.cipher_str = "cts(cbc(aes))",
|
|
.keysize = 16,
|
|
.ivsize = 16,
|
|
},
|
|
[FS_ENCRYPTION_MODE_ADIANTUM] = {
|
|
.friendly_name = "Adiantum",
|
|
.cipher_str = "adiantum(xchacha12,aes)",
|
|
.keysize = 32,
|
|
.ivsize = 32,
|
|
},
|
|
};
|
|
|
|
static struct fscrypt_mode *
|
|
select_encryption_mode(const struct fscrypt_info *ci, const struct inode *inode)
|
|
{
|
|
if (!fscrypt_valid_enc_modes(ci->ci_data_mode, ci->ci_filename_mode)) {
|
|
fscrypt_warn(inode->i_sb,
|
|
"inode %lu uses unsupported encryption modes (contents mode %d, filenames mode %d)",
|
|
inode->i_ino, ci->ci_data_mode,
|
|
ci->ci_filename_mode);
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (S_ISREG(inode->i_mode))
|
|
return &available_modes[ci->ci_data_mode];
|
|
|
|
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode))
|
|
return &available_modes[ci->ci_filename_mode];
|
|
|
|
WARN_ONCE(1, "fscrypt: filesystem tried to load encryption info for inode %lu, which is not encryptable (file type %d)\n",
|
|
inode->i_ino, (inode->i_mode & S_IFMT));
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
/* Find the master key, then derive the inode's actual encryption key */
|
|
static int find_and_derive_key(const struct inode *inode,
|
|
const struct fscrypt_context *ctx,
|
|
u8 *derived_key, const struct fscrypt_mode *mode)
|
|
{
|
|
struct key *key;
|
|
const struct fscrypt_key *payload;
|
|
int err;
|
|
|
|
key = find_and_lock_process_key(FS_KEY_DESC_PREFIX,
|
|
ctx->master_key_descriptor,
|
|
mode->keysize, &payload);
|
|
if (key == ERR_PTR(-ENOKEY) && inode->i_sb->s_cop->key_prefix) {
|
|
key = find_and_lock_process_key(inode->i_sb->s_cop->key_prefix,
|
|
ctx->master_key_descriptor,
|
|
mode->keysize, &payload);
|
|
}
|
|
if (IS_ERR(key))
|
|
return PTR_ERR(key);
|
|
|
|
if (ctx->flags & FS_POLICY_FLAG_DIRECT_KEY) {
|
|
if (mode->ivsize < offsetofend(union fscrypt_iv, nonce)) {
|
|
fscrypt_warn(inode->i_sb,
|
|
"direct key mode not allowed with %s",
|
|
mode->friendly_name);
|
|
err = -EINVAL;
|
|
} else if (ctx->contents_encryption_mode !=
|
|
ctx->filenames_encryption_mode) {
|
|
fscrypt_warn(inode->i_sb,
|
|
"direct key mode not allowed with different contents and filenames modes");
|
|
err = -EINVAL;
|
|
} else {
|
|
memcpy(derived_key, payload->raw, mode->keysize);
|
|
err = 0;
|
|
}
|
|
} else {
|
|
err = derive_key_aes(payload->raw, ctx, derived_key,
|
|
mode->keysize);
|
|
}
|
|
up_read(&key->sem);
|
|
key_put(key);
|
|
return err;
|
|
}
|
|
|
|
/* Allocate and key a symmetric cipher object for the given encryption mode */
|
|
static struct crypto_skcipher *
|
|
allocate_skcipher_for_mode(struct fscrypt_mode *mode, const u8 *raw_key,
|
|
const struct inode *inode)
|
|
{
|
|
struct crypto_skcipher *tfm;
|
|
int err;
|
|
|
|
tfm = crypto_alloc_skcipher(mode->cipher_str, 0, 0);
|
|
if (IS_ERR(tfm)) {
|
|
fscrypt_warn(inode->i_sb,
|
|
"error allocating '%s' transform for inode %lu: %ld",
|
|
mode->cipher_str, inode->i_ino, PTR_ERR(tfm));
|
|
return tfm;
|
|
}
|
|
if (unlikely(!mode->logged_impl_name)) {
|
|
/*
|
|
* fscrypt performance can vary greatly depending on which
|
|
* crypto algorithm implementation is used. Help people debug
|
|
* performance problems by logging the ->cra_driver_name the
|
|
* first time a mode is used. Note that multiple threads can
|
|
* race here, but it doesn't really matter.
|
|
*/
|
|
mode->logged_impl_name = true;
|
|
pr_info("fscrypt: %s using implementation \"%s\"\n",
|
|
mode->friendly_name,
|
|
crypto_skcipher_alg(tfm)->base.cra_driver_name);
|
|
}
|
|
crypto_skcipher_set_flags(tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
|
|
err = crypto_skcipher_setkey(tfm, raw_key, mode->keysize);
|
|
if (err)
|
|
goto err_free_tfm;
|
|
|
|
return tfm;
|
|
|
|
err_free_tfm:
|
|
crypto_free_skcipher(tfm);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
/* Master key referenced by FS_POLICY_FLAG_DIRECT_KEY policy */
|
|
struct fscrypt_master_key {
|
|
struct hlist_node mk_node;
|
|
refcount_t mk_refcount;
|
|
const struct fscrypt_mode *mk_mode;
|
|
struct crypto_skcipher *mk_ctfm;
|
|
u8 mk_descriptor[FS_KEY_DESCRIPTOR_SIZE];
|
|
u8 mk_raw[FS_MAX_KEY_SIZE];
|
|
};
|
|
|
|
static void free_master_key(struct fscrypt_master_key *mk)
|
|
{
|
|
if (mk) {
|
|
crypto_free_skcipher(mk->mk_ctfm);
|
|
kzfree(mk);
|
|
}
|
|
}
|
|
|
|
static void put_master_key(struct fscrypt_master_key *mk)
|
|
{
|
|
if (!refcount_dec_and_lock(&mk->mk_refcount, &fscrypt_master_keys_lock))
|
|
return;
|
|
hash_del(&mk->mk_node);
|
|
spin_unlock(&fscrypt_master_keys_lock);
|
|
|
|
free_master_key(mk);
|
|
}
|
|
|
|
/*
|
|
* Find/insert the given master key into the fscrypt_master_keys table. If
|
|
* found, it is returned with elevated refcount, and 'to_insert' is freed if
|
|
* non-NULL. If not found, 'to_insert' is inserted and returned if it's
|
|
* non-NULL; otherwise NULL is returned.
|
|
*/
|
|
static struct fscrypt_master_key *
|
|
find_or_insert_master_key(struct fscrypt_master_key *to_insert,
|
|
const u8 *raw_key, const struct fscrypt_mode *mode,
|
|
const struct fscrypt_info *ci)
|
|
{
|
|
unsigned long hash_key;
|
|
struct fscrypt_master_key *mk;
|
|
|
|
/*
|
|
* Careful: to avoid potentially leaking secret key bytes via timing
|
|
* information, we must key the hash table by descriptor rather than by
|
|
* raw key, and use crypto_memneq() when comparing raw keys.
|
|
*/
|
|
|
|
BUILD_BUG_ON(sizeof(hash_key) > FS_KEY_DESCRIPTOR_SIZE);
|
|
memcpy(&hash_key, ci->ci_master_key_descriptor, sizeof(hash_key));
|
|
|
|
spin_lock(&fscrypt_master_keys_lock);
|
|
hash_for_each_possible(fscrypt_master_keys, mk, mk_node, hash_key) {
|
|
if (memcmp(ci->ci_master_key_descriptor, mk->mk_descriptor,
|
|
FS_KEY_DESCRIPTOR_SIZE) != 0)
|
|
continue;
|
|
if (mode != mk->mk_mode)
|
|
continue;
|
|
if (crypto_memneq(raw_key, mk->mk_raw, mode->keysize))
|
|
continue;
|
|
/* using existing tfm with same (descriptor, mode, raw_key) */
|
|
refcount_inc(&mk->mk_refcount);
|
|
spin_unlock(&fscrypt_master_keys_lock);
|
|
free_master_key(to_insert);
|
|
return mk;
|
|
}
|
|
if (to_insert)
|
|
hash_add(fscrypt_master_keys, &to_insert->mk_node, hash_key);
|
|
spin_unlock(&fscrypt_master_keys_lock);
|
|
return to_insert;
|
|
}
|
|
|
|
/* Prepare to encrypt directly using the master key in the given mode */
|
|
static struct fscrypt_master_key *
|
|
fscrypt_get_master_key(const struct fscrypt_info *ci, struct fscrypt_mode *mode,
|
|
const u8 *raw_key, const struct inode *inode)
|
|
{
|
|
struct fscrypt_master_key *mk;
|
|
int err;
|
|
|
|
/* Is there already a tfm for this key? */
|
|
mk = find_or_insert_master_key(NULL, raw_key, mode, ci);
|
|
if (mk)
|
|
return mk;
|
|
|
|
/* Nope, allocate one. */
|
|
mk = kzalloc(sizeof(*mk), GFP_NOFS);
|
|
if (!mk)
|
|
return ERR_PTR(-ENOMEM);
|
|
refcount_set(&mk->mk_refcount, 1);
|
|
mk->mk_mode = mode;
|
|
mk->mk_ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
|
|
if (IS_ERR(mk->mk_ctfm)) {
|
|
err = PTR_ERR(mk->mk_ctfm);
|
|
mk->mk_ctfm = NULL;
|
|
goto err_free_mk;
|
|
}
|
|
memcpy(mk->mk_descriptor, ci->ci_master_key_descriptor,
|
|
FS_KEY_DESCRIPTOR_SIZE);
|
|
memcpy(mk->mk_raw, raw_key, mode->keysize);
|
|
|
|
return find_or_insert_master_key(mk, raw_key, mode, ci);
|
|
|
|
err_free_mk:
|
|
free_master_key(mk);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
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)) {
|
|
fscrypt_warn(NULL,
|
|
"error allocating SHA-256 transform: %ld",
|
|
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;
|
|
|
|
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);
|
|
}
|
|
|
|
/*
|
|
* Given the encryption mode and key (normally the derived key, but for
|
|
* FS_POLICY_FLAG_DIRECT_KEY mode it's the master key), set up the inode's
|
|
* symmetric cipher transform object(s).
|
|
*/
|
|
static int setup_crypto_transform(struct fscrypt_info *ci,
|
|
struct fscrypt_mode *mode,
|
|
const u8 *raw_key, const struct inode *inode)
|
|
{
|
|
struct fscrypt_master_key *mk;
|
|
struct crypto_skcipher *ctfm;
|
|
int err;
|
|
|
|
if (ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY) {
|
|
mk = fscrypt_get_master_key(ci, mode, raw_key, inode);
|
|
if (IS_ERR(mk))
|
|
return PTR_ERR(mk);
|
|
ctfm = mk->mk_ctfm;
|
|
} else {
|
|
mk = NULL;
|
|
ctfm = allocate_skcipher_for_mode(mode, raw_key, inode);
|
|
if (IS_ERR(ctfm))
|
|
return PTR_ERR(ctfm);
|
|
}
|
|
ci->ci_master_key = mk;
|
|
ci->ci_ctfm = ctfm;
|
|
|
|
if (mode->needs_essiv) {
|
|
/* ESSIV implies 16-byte IVs which implies !DIRECT_KEY */
|
|
WARN_ON(mode->ivsize != AES_BLOCK_SIZE);
|
|
WARN_ON(ci->ci_flags & FS_POLICY_FLAG_DIRECT_KEY);
|
|
|
|
err = init_essiv_generator(ci, raw_key, mode->keysize);
|
|
if (err) {
|
|
fscrypt_warn(inode->i_sb,
|
|
"error initializing ESSIV generator for inode %lu: %d",
|
|
inode->i_ino, err);
|
|
return err;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void put_crypt_info(struct fscrypt_info *ci)
|
|
{
|
|
if (!ci)
|
|
return;
|
|
|
|
if (ci->ci_master_key) {
|
|
put_master_key(ci->ci_master_key);
|
|
} else {
|
|
crypto_free_skcipher(ci->ci_ctfm);
|
|
crypto_free_cipher(ci->ci_essiv_tfm);
|
|
}
|
|
kmem_cache_free(fscrypt_info_cachep, ci);
|
|
}
|
|
|
|
int fscrypt_get_encryption_info(struct inode *inode)
|
|
{
|
|
struct fscrypt_info *crypt_info;
|
|
struct fscrypt_context ctx;
|
|
struct fscrypt_mode *mode;
|
|
u8 *raw_key = NULL;
|
|
int res;
|
|
|
|
if (inode->i_crypt_info)
|
|
return 0;
|
|
|
|
res = fscrypt_initialize(inode->i_sb->s_cop->flags);
|
|
if (res)
|
|
return res;
|
|
|
|
res = inode->i_sb->s_cop->get_context(inode, &ctx, sizeof(ctx));
|
|
if (res < 0) {
|
|
if (!fscrypt_dummy_context_enabled(inode) ||
|
|
IS_ENCRYPTED(inode))
|
|
return res;
|
|
/* Fake up a context for an unencrypted directory */
|
|
memset(&ctx, 0, sizeof(ctx));
|
|
ctx.format = FS_ENCRYPTION_CONTEXT_FORMAT_V1;
|
|
ctx.contents_encryption_mode = FS_ENCRYPTION_MODE_AES_256_XTS;
|
|
ctx.filenames_encryption_mode = FS_ENCRYPTION_MODE_AES_256_CTS;
|
|
memset(ctx.master_key_descriptor, 0x42, FS_KEY_DESCRIPTOR_SIZE);
|
|
} else if (res != sizeof(ctx)) {
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (ctx.format != FS_ENCRYPTION_CONTEXT_FORMAT_V1)
|
|
return -EINVAL;
|
|
|
|
if (ctx.flags & ~FS_POLICY_FLAGS_VALID)
|
|
return -EINVAL;
|
|
|
|
crypt_info = kmem_cache_zalloc(fscrypt_info_cachep, GFP_NOFS);
|
|
if (!crypt_info)
|
|
return -ENOMEM;
|
|
|
|
crypt_info->ci_flags = ctx.flags;
|
|
crypt_info->ci_data_mode = ctx.contents_encryption_mode;
|
|
crypt_info->ci_filename_mode = ctx.filenames_encryption_mode;
|
|
memcpy(crypt_info->ci_master_key_descriptor, ctx.master_key_descriptor,
|
|
FS_KEY_DESCRIPTOR_SIZE);
|
|
memcpy(crypt_info->ci_nonce, ctx.nonce, FS_KEY_DERIVATION_NONCE_SIZE);
|
|
|
|
mode = select_encryption_mode(crypt_info, inode);
|
|
if (IS_ERR(mode)) {
|
|
res = PTR_ERR(mode);
|
|
goto out;
|
|
}
|
|
WARN_ON(mode->ivsize > FSCRYPT_MAX_IV_SIZE);
|
|
crypt_info->ci_mode = mode;
|
|
|
|
/*
|
|
* This cannot be a stack buffer because it may be passed to the
|
|
* scatterlist crypto API as part of key derivation.
|
|
*/
|
|
res = -ENOMEM;
|
|
raw_key = kmalloc(mode->keysize, GFP_NOFS);
|
|
if (!raw_key)
|
|
goto out;
|
|
|
|
res = find_and_derive_key(inode, &ctx, raw_key, mode);
|
|
if (res)
|
|
goto out;
|
|
|
|
res = setup_crypto_transform(crypt_info, mode, raw_key, inode);
|
|
if (res)
|
|
goto out;
|
|
|
|
if (cmpxchg(&inode->i_crypt_info, NULL, crypt_info) == NULL)
|
|
crypt_info = NULL;
|
|
out:
|
|
if (res == -ENOKEY)
|
|
res = 0;
|
|
put_crypt_info(crypt_info);
|
|
kzfree(raw_key);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(fscrypt_get_encryption_info);
|
|
|
|
void fscrypt_put_encryption_info(struct inode *inode)
|
|
{
|
|
put_crypt_info(inode->i_crypt_info);
|
|
inode->i_crypt_info = NULL;
|
|
}
|
|
EXPORT_SYMBOL(fscrypt_put_encryption_info);
|