mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-25 21:24:08 +08:00
ext4 crypto: filename encryption facilities
Signed-off-by: Uday Savagaonkar <savagaon@google.com> Signed-off-by: Ildar Muslukhov <ildarm@google.com> Signed-off-by: Michael Halcrow <mhalcrow@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Michael Halcrow
Theodore Ts'o
parent
c9c7429c2e
commit
d5d0e8c720
@ -12,4 +12,5 @@ ext4-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
|
||||
|
||||
ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
|
||||
ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
|
||||
ext4-$(CONFIG_EXT4_FS_ENCRYPTION) += crypto_policy.o crypto.o crypto_key.o
|
||||
ext4-$(CONFIG_EXT4_FS_ENCRYPTION) += crypto_policy.o crypto.o \
|
||||
crypto_key.o crypto_fname.o
|
||||
|
||||
709
fs/ext4/crypto_fname.c
Normal file
709
fs/ext4/crypto_fname.c
Normal file
@ -0,0 +1,709 @@
|
||||
/*
|
||||
* linux/fs/ext4/crypto_fname.c
|
||||
*
|
||||
* Copyright (C) 2015, Google, Inc.
|
||||
*
|
||||
* This contains functions for filename crypto management in ext4
|
||||
*
|
||||
* Written by Uday Savagaonkar, 2014.
|
||||
*
|
||||
* This has not yet undergone a rigorous security audit.
|
||||
*
|
||||
*/
|
||||
|
||||
#include <crypto/hash.h>
|
||||
#include <crypto/sha.h>
|
||||
#include <keys/encrypted-type.h>
|
||||
#include <keys/user-type.h>
|
||||
#include <linux/crypto.h>
|
||||
#include <linux/gfp.h>
|
||||
#include <linux/kernel.h>
|
||||
#include <linux/key.h>
|
||||
#include <linux/key.h>
|
||||
#include <linux/list.h>
|
||||
#include <linux/mempool.h>
|
||||
#include <linux/random.h>
|
||||
#include <linux/scatterlist.h>
|
||||
#include <linux/spinlock_types.h>
|
||||
|
||||
#include "ext4.h"
|
||||
#include "ext4_crypto.h"
|
||||
#include "xattr.h"
|
||||
|
||||
/**
|
||||
* ext4_dir_crypt_complete() -
|
||||
*/
|
||||
static void ext4_dir_crypt_complete(struct crypto_async_request *req, int res)
|
||||
{
|
||||
struct ext4_completion_result *ecr = req->data;
|
||||
|
||||
if (res == -EINPROGRESS)
|
||||
return;
|
||||
ecr->res = res;
|
||||
complete(&ecr->completion);
|
||||
}
|
||||
|
||||
bool ext4_valid_filenames_enc_mode(uint32_t mode)
|
||||
{
|
||||
return (mode == EXT4_ENCRYPTION_MODE_AES_256_CTS);
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_encrypt() -
|
||||
*
|
||||
* This function encrypts the input filename, and returns the length of the
|
||||
* ciphertext. Errors are returned as negative numbers. We trust the caller to
|
||||
* allocate sufficient memory to oname string.
|
||||
*/
|
||||
static int ext4_fname_encrypt(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct qstr *iname,
|
||||
struct ext4_str *oname)
|
||||
{
|
||||
u32 ciphertext_len;
|
||||
struct ablkcipher_request *req = NULL;
|
||||
DECLARE_EXT4_COMPLETION_RESULT(ecr);
|
||||
struct crypto_ablkcipher *tfm = ctx->ctfm;
|
||||
int res = 0;
|
||||
char iv[EXT4_CRYPTO_BLOCK_SIZE];
|
||||
struct scatterlist sg[1];
|
||||
char *workbuf;
|
||||
|
||||
if (iname->len <= 0 || iname->len > ctx->lim)
|
||||
return -EIO;
|
||||
|
||||
ciphertext_len = (iname->len < EXT4_CRYPTO_BLOCK_SIZE) ?
|
||||
EXT4_CRYPTO_BLOCK_SIZE : iname->len;
|
||||
ciphertext_len = (ciphertext_len > ctx->lim)
|
||||
? ctx->lim : ciphertext_len;
|
||||
|
||||
/* Allocate request */
|
||||
req = ablkcipher_request_alloc(tfm, GFP_NOFS);
|
||||
if (!req) {
|
||||
printk_ratelimited(
|
||||
KERN_ERR "%s: crypto_request_alloc() failed\n", __func__);
|
||||
return -ENOMEM;
|
||||
}
|
||||
ablkcipher_request_set_callback(req,
|
||||
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
|
||||
ext4_dir_crypt_complete, &ecr);
|
||||
|
||||
/* Map the workpage */
|
||||
workbuf = kmap(ctx->workpage);
|
||||
|
||||
/* Copy the input */
|
||||
memcpy(workbuf, iname->name, iname->len);
|
||||
if (iname->len < ciphertext_len)
|
||||
memset(workbuf + iname->len, 0, ciphertext_len - iname->len);
|
||||
|
||||
/* Initialize IV */
|
||||
memset(iv, 0, EXT4_CRYPTO_BLOCK_SIZE);
|
||||
|
||||
/* Create encryption request */
|
||||
sg_init_table(sg, 1);
|
||||
sg_set_page(sg, ctx->workpage, PAGE_SIZE, 0);
|
||||
ablkcipher_request_set_crypt(req, sg, sg, iname->len, iv);
|
||||
res = crypto_ablkcipher_encrypt(req);
|
||||
if (res == -EINPROGRESS || res == -EBUSY) {
|
||||
BUG_ON(req->base.data != &ecr);
|
||||
wait_for_completion(&ecr.completion);
|
||||
res = ecr.res;
|
||||
}
|
||||
if (res >= 0) {
|
||||
/* Copy the result to output */
|
||||
memcpy(oname->name, workbuf, ciphertext_len);
|
||||
res = ciphertext_len;
|
||||
}
|
||||
kunmap(ctx->workpage);
|
||||
ablkcipher_request_free(req);
|
||||
if (res < 0) {
|
||||
printk_ratelimited(
|
||||
KERN_ERR "%s: Error (error code %d)\n", __func__, res);
|
||||
}
|
||||
oname->len = ciphertext_len;
|
||||
return res;
|
||||
}
|
||||
|
||||
/*
|
||||
* ext4_fname_decrypt()
|
||||
* This function decrypts the input filename, and returns
|
||||
* the length of the plaintext.
|
||||
* Errors are returned as negative numbers.
|
||||
* We trust the caller to allocate sufficient memory to oname string.
|
||||
*/
|
||||
static int ext4_fname_decrypt(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct ext4_str *iname,
|
||||
struct ext4_str *oname)
|
||||
{
|
||||
struct ext4_str tmp_in[2], tmp_out[1];
|
||||
struct ablkcipher_request *req = NULL;
|
||||
DECLARE_EXT4_COMPLETION_RESULT(ecr);
|
||||
struct scatterlist sg[1];
|
||||
struct crypto_ablkcipher *tfm = ctx->ctfm;
|
||||
int res = 0;
|
||||
char iv[EXT4_CRYPTO_BLOCK_SIZE];
|
||||
char *workbuf;
|
||||
|
||||
if (iname->len <= 0 || iname->len > ctx->lim)
|
||||
return -EIO;
|
||||
|
||||
tmp_in[0].name = iname->name;
|
||||
tmp_in[0].len = iname->len;
|
||||
tmp_out[0].name = oname->name;
|
||||
|
||||
/* Allocate request */
|
||||
req = ablkcipher_request_alloc(tfm, GFP_NOFS);
|
||||
if (!req) {
|
||||
printk_ratelimited(
|
||||
KERN_ERR "%s: crypto_request_alloc() failed\n", __func__);
|
||||
return -ENOMEM;
|
||||
}
|
||||
ablkcipher_request_set_callback(req,
|
||||
CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
|
||||
ext4_dir_crypt_complete, &ecr);
|
||||
|
||||
/* Map the workpage */
|
||||
workbuf = kmap(ctx->workpage);
|
||||
|
||||
/* Copy the input */
|
||||
memcpy(workbuf, iname->name, iname->len);
|
||||
|
||||
/* Initialize IV */
|
||||
memset(iv, 0, EXT4_CRYPTO_BLOCK_SIZE);
|
||||
|
||||
/* Create encryption request */
|
||||
sg_init_table(sg, 1);
|
||||
sg_set_page(sg, ctx->workpage, PAGE_SIZE, 0);
|
||||
ablkcipher_request_set_crypt(req, sg, sg, iname->len, iv);
|
||||
res = crypto_ablkcipher_decrypt(req);
|
||||
if (res == -EINPROGRESS || res == -EBUSY) {
|
||||
BUG_ON(req->base.data != &ecr);
|
||||
wait_for_completion(&ecr.completion);
|
||||
res = ecr.res;
|
||||
}
|
||||
if (res >= 0) {
|
||||
/* Copy the result to output */
|
||||
memcpy(oname->name, workbuf, iname->len);
|
||||
res = iname->len;
|
||||
}
|
||||
kunmap(ctx->workpage);
|
||||
ablkcipher_request_free(req);
|
||||
if (res < 0) {
|
||||
printk_ratelimited(
|
||||
KERN_ERR "%s: Error in ext4_fname_encrypt (error code %d)\n",
|
||||
__func__, res);
|
||||
return res;
|
||||
}
|
||||
|
||||
oname->len = strnlen(oname->name, iname->len);
|
||||
return oname->len;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_encode_digest() -
|
||||
*
|
||||
* Encodes the input digest using characters from the set [a-zA-Z0-9_+].
|
||||
* The encoded string is roughly 4/3 times the size of the input string.
|
||||
*/
|
||||
int ext4_fname_encode_digest(char *dst, char *src, u32 len)
|
||||
{
|
||||
static const char *lookup_table =
|
||||
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_+";
|
||||
u32 current_chunk, num_chunks, i;
|
||||
char tmp_buf[3];
|
||||
u32 c0, c1, c2, c3;
|
||||
|
||||
current_chunk = 0;
|
||||
num_chunks = len/3;
|
||||
for (i = 0; i < num_chunks; i++) {
|
||||
c0 = src[3*i] & 0x3f;
|
||||
c1 = (((src[3*i]>>6)&0x3) | ((src[3*i+1] & 0xf)<<2)) & 0x3f;
|
||||
c2 = (((src[3*i+1]>>4)&0xf) | ((src[3*i+2] & 0x3)<<4)) & 0x3f;
|
||||
c3 = (src[3*i+2]>>2) & 0x3f;
|
||||
dst[4*i] = lookup_table[c0];
|
||||
dst[4*i+1] = lookup_table[c1];
|
||||
dst[4*i+2] = lookup_table[c2];
|
||||
dst[4*i+3] = lookup_table[c3];
|
||||
}
|
||||
if (i*3 < len) {
|
||||
memset(tmp_buf, 0, 3);
|
||||
memcpy(tmp_buf, &src[3*i], len-3*i);
|
||||
c0 = tmp_buf[0] & 0x3f;
|
||||
c1 = (((tmp_buf[0]>>6)&0x3) | ((tmp_buf[1] & 0xf)<<2)) & 0x3f;
|
||||
c2 = (((tmp_buf[1]>>4)&0xf) | ((tmp_buf[2] & 0x3)<<4)) & 0x3f;
|
||||
c3 = (tmp_buf[2]>>2) & 0x3f;
|
||||
dst[4*i] = lookup_table[c0];
|
||||
dst[4*i+1] = lookup_table[c1];
|
||||
dst[4*i+2] = lookup_table[c2];
|
||||
dst[4*i+3] = lookup_table[c3];
|
||||
i++;
|
||||
}
|
||||
return (i * 4);
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_hash() -
|
||||
*
|
||||
* This function computes the hash of the input filename, and sets the output
|
||||
* buffer to the *encoded* digest. It returns the length of the digest as its
|
||||
* return value. Errors are returned as negative numbers. We trust the caller
|
||||
* to allocate sufficient memory to oname string.
|
||||
*/
|
||||
static int ext4_fname_hash(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct ext4_str *iname,
|
||||
struct ext4_str *oname)
|
||||
{
|
||||
struct scatterlist sg;
|
||||
struct hash_desc desc = {
|
||||
.tfm = (struct crypto_hash *)ctx->htfm,
|
||||
.flags = CRYPTO_TFM_REQ_MAY_SLEEP
|
||||
};
|
||||
int res = 0;
|
||||
|
||||
if (iname->len <= EXT4_FNAME_CRYPTO_DIGEST_SIZE) {
|
||||
res = ext4_fname_encode_digest(oname->name, iname->name,
|
||||
iname->len);
|
||||
oname->len = res;
|
||||
return res;
|
||||
}
|
||||
|
||||
sg_init_one(&sg, iname->name, iname->len);
|
||||
res = crypto_hash_init(&desc);
|
||||
if (res) {
|
||||
printk(KERN_ERR
|
||||
"%s: Error initializing crypto hash; res = [%d]\n",
|
||||
__func__, res);
|
||||
goto out;
|
||||
}
|
||||
res = crypto_hash_update(&desc, &sg, iname->len);
|
||||
if (res) {
|
||||
printk(KERN_ERR
|
||||
"%s: Error updating crypto hash; res = [%d]\n",
|
||||
__func__, res);
|
||||
goto out;
|
||||
}
|
||||
res = crypto_hash_final(&desc,
|
||||
&oname->name[EXT4_FNAME_CRYPTO_DIGEST_SIZE]);
|
||||
if (res) {
|
||||
printk(KERN_ERR
|
||||
"%s: Error finalizing crypto hash; res = [%d]\n",
|
||||
__func__, res);
|
||||
goto out;
|
||||
}
|
||||
/* Encode the digest as a printable string--this will increase the
|
||||
* size of the digest */
|
||||
oname->name[0] = 'I';
|
||||
res = ext4_fname_encode_digest(oname->name+1,
|
||||
&oname->name[EXT4_FNAME_CRYPTO_DIGEST_SIZE],
|
||||
EXT4_FNAME_CRYPTO_DIGEST_SIZE) + 1;
|
||||
oname->len = res;
|
||||
out:
|
||||
return res;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_free_fname_crypto_ctx() -
|
||||
*
|
||||
* Frees up a crypto context.
|
||||
*/
|
||||
void ext4_free_fname_crypto_ctx(struct ext4_fname_crypto_ctx *ctx)
|
||||
{
|
||||
if (ctx == NULL || IS_ERR(ctx))
|
||||
return;
|
||||
|
||||
if (ctx->ctfm && !IS_ERR(ctx->ctfm))
|
||||
crypto_free_ablkcipher(ctx->ctfm);
|
||||
if (ctx->htfm && !IS_ERR(ctx->htfm))
|
||||
crypto_free_hash(ctx->htfm);
|
||||
if (ctx->workpage && !IS_ERR(ctx->workpage))
|
||||
__free_page(ctx->workpage);
|
||||
kfree(ctx);
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_put_fname_crypto_ctx() -
|
||||
*
|
||||
* Return: The crypto context onto free list. If the free list is above a
|
||||
* threshold, completely frees up the context, and returns the memory.
|
||||
*
|
||||
* TODO: Currently we directly free the crypto context. Eventually we should
|
||||
* add code it to return to free list. Such an approach will increase
|
||||
* efficiency of directory lookup.
|
||||
*/
|
||||
void ext4_put_fname_crypto_ctx(struct ext4_fname_crypto_ctx **ctx)
|
||||
{
|
||||
if (*ctx == NULL || IS_ERR(*ctx))
|
||||
return;
|
||||
ext4_free_fname_crypto_ctx(*ctx);
|
||||
*ctx = NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_search_fname_crypto_ctx() -
|
||||
*/
|
||||
static struct ext4_fname_crypto_ctx *ext4_search_fname_crypto_ctx(
|
||||
const struct ext4_encryption_key *key)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_alloc_fname_crypto_ctx() -
|
||||
*/
|
||||
struct ext4_fname_crypto_ctx *ext4_alloc_fname_crypto_ctx(
|
||||
const struct ext4_encryption_key *key)
|
||||
{
|
||||
struct ext4_fname_crypto_ctx *ctx;
|
||||
|
||||
ctx = kmalloc(sizeof(struct ext4_fname_crypto_ctx), GFP_NOFS);
|
||||
if (ctx == NULL)
|
||||
return ERR_PTR(-ENOMEM);
|
||||
if (key->mode == EXT4_ENCRYPTION_MODE_INVALID) {
|
||||
/* This will automatically set key mode to invalid
|
||||
* As enum for ENCRYPTION_MODE_INVALID is zero */
|
||||
memset(&ctx->key, 0, sizeof(ctx->key));
|
||||
} else {
|
||||
memcpy(&ctx->key, key, sizeof(struct ext4_encryption_key));
|
||||
}
|
||||
ctx->has_valid_key = (EXT4_ENCRYPTION_MODE_INVALID == key->mode)
|
||||
? 0 : 1;
|
||||
ctx->ctfm_key_is_ready = 0;
|
||||
ctx->ctfm = NULL;
|
||||
ctx->htfm = NULL;
|
||||
ctx->workpage = NULL;
|
||||
return ctx;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_get_fname_crypto_ctx() -
|
||||
*
|
||||
* Allocates a free crypto context and initializes it to hold
|
||||
* the crypto material for the inode.
|
||||
*
|
||||
* Return: NULL if not encrypted. Error value on error. Valid pointer otherwise.
|
||||
*/
|
||||
struct ext4_fname_crypto_ctx *ext4_get_fname_crypto_ctx(
|
||||
struct inode *inode, u32 max_ciphertext_len)
|
||||
{
|
||||
struct ext4_fname_crypto_ctx *ctx;
|
||||
struct ext4_inode_info *ei = EXT4_I(inode);
|
||||
int res;
|
||||
|
||||
/* Check if the crypto policy is set on the inode */
|
||||
res = ext4_encrypted_inode(inode);
|
||||
if (res == 0)
|
||||
return NULL;
|
||||
|
||||
if (!ext4_has_encryption_key(inode))
|
||||
ext4_generate_encryption_key(inode);
|
||||
|
||||
/* Get a crypto context based on the key.
|
||||
* A new context is allocated if no context matches the requested key.
|
||||
*/
|
||||
ctx = ext4_search_fname_crypto_ctx(&(ei->i_encryption_key));
|
||||
if (ctx == NULL)
|
||||
ctx = ext4_alloc_fname_crypto_ctx(&(ei->i_encryption_key));
|
||||
if (IS_ERR(ctx))
|
||||
return ctx;
|
||||
|
||||
if (ctx->has_valid_key) {
|
||||
if (ctx->key.mode != EXT4_ENCRYPTION_MODE_AES_256_CTS) {
|
||||
printk_once(KERN_WARNING
|
||||
"ext4: unsupported key mode %d\n",
|
||||
ctx->key.mode);
|
||||
return ERR_PTR(-ENOKEY);
|
||||
}
|
||||
|
||||
/* As a first cut, we will allocate new tfm in every call.
|
||||
* later, we will keep the tfm around, in case the key gets
|
||||
* re-used */
|
||||
if (ctx->ctfm == NULL) {
|
||||
ctx->ctfm = crypto_alloc_ablkcipher("cts(cbc(aes))",
|
||||
0, 0);
|
||||
}
|
||||
if (IS_ERR(ctx->ctfm)) {
|
||||
res = PTR_ERR(ctx->ctfm);
|
||||
printk(
|
||||
KERN_DEBUG "%s: error (%d) allocating crypto tfm\n",
|
||||
__func__, res);
|
||||
ctx->ctfm = NULL;
|
||||
ext4_put_fname_crypto_ctx(&ctx);
|
||||
return ERR_PTR(res);
|
||||
}
|
||||
if (ctx->ctfm == NULL) {
|
||||
printk(
|
||||
KERN_DEBUG "%s: could not allocate crypto tfm\n",
|
||||
__func__);
|
||||
ext4_put_fname_crypto_ctx(&ctx);
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
if (ctx->workpage == NULL)
|
||||
ctx->workpage = alloc_page(GFP_NOFS);
|
||||
if (IS_ERR(ctx->workpage)) {
|
||||
res = PTR_ERR(ctx->workpage);
|
||||
printk(
|
||||
KERN_DEBUG "%s: error (%d) allocating work page\n",
|
||||
__func__, res);
|
||||
ctx->workpage = NULL;
|
||||
ext4_put_fname_crypto_ctx(&ctx);
|
||||
return ERR_PTR(res);
|
||||
}
|
||||
if (ctx->workpage == NULL) {
|
||||
printk(
|
||||
KERN_DEBUG "%s: could not allocate work page\n",
|
||||
__func__);
|
||||
ext4_put_fname_crypto_ctx(&ctx);
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
ctx->lim = max_ciphertext_len;
|
||||
crypto_ablkcipher_clear_flags(ctx->ctfm, ~0);
|
||||
crypto_tfm_set_flags(crypto_ablkcipher_tfm(ctx->ctfm),
|
||||
CRYPTO_TFM_REQ_WEAK_KEY);
|
||||
|
||||
/* If we are lucky, we will get a context that is already
|
||||
* set up with the right key. Else, we will have to
|
||||
* set the key */
|
||||
if (!ctx->ctfm_key_is_ready) {
|
||||
/* Since our crypto objectives for filename encryption
|
||||
* are pretty weak,
|
||||
* we directly use the inode master key */
|
||||
res = crypto_ablkcipher_setkey(ctx->ctfm,
|
||||
ctx->key.raw, ctx->key.size);
|
||||
if (res) {
|
||||
ext4_put_fname_crypto_ctx(&ctx);
|
||||
return ERR_PTR(-EIO);
|
||||
}
|
||||
ctx->ctfm_key_is_ready = 1;
|
||||
} else {
|
||||
/* In the current implementation, key should never be
|
||||
* marked "ready" for a context that has just been
|
||||
* allocated. So we should never reach here */
|
||||
BUG();
|
||||
}
|
||||
}
|
||||
if (ctx->htfm == NULL)
|
||||
ctx->htfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
|
||||
if (IS_ERR(ctx->htfm)) {
|
||||
res = PTR_ERR(ctx->htfm);
|
||||
printk(KERN_DEBUG "%s: error (%d) allocating hash tfm\n",
|
||||
__func__, res);
|
||||
ctx->htfm = NULL;
|
||||
ext4_put_fname_crypto_ctx(&ctx);
|
||||
return ERR_PTR(res);
|
||||
}
|
||||
if (ctx->htfm == NULL) {
|
||||
printk(KERN_DEBUG "%s: could not allocate hash tfm\n",
|
||||
__func__);
|
||||
ext4_put_fname_crypto_ctx(&ctx);
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
|
||||
return ctx;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_crypto_round_up() -
|
||||
*
|
||||
* Return: The next multiple of block size
|
||||
*/
|
||||
u32 ext4_fname_crypto_round_up(u32 size, u32 blksize)
|
||||
{
|
||||
return ((size+blksize-1)/blksize)*blksize;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_crypto_namelen_on_disk() -
|
||||
*/
|
||||
int ext4_fname_crypto_namelen_on_disk(struct ext4_fname_crypto_ctx *ctx,
|
||||
u32 namelen)
|
||||
{
|
||||
u32 ciphertext_len;
|
||||
|
||||
if (ctx == NULL)
|
||||
return -EIO;
|
||||
if (!(ctx->has_valid_key))
|
||||
return -EACCES;
|
||||
ciphertext_len = (namelen < EXT4_CRYPTO_BLOCK_SIZE) ?
|
||||
EXT4_CRYPTO_BLOCK_SIZE : namelen;
|
||||
ciphertext_len = (ciphertext_len > ctx->lim)
|
||||
? ctx->lim : ciphertext_len;
|
||||
return (int) ciphertext_len;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_crypto_alloc_obuff() -
|
||||
*
|
||||
* Allocates an output buffer that is sufficient for the crypto operation
|
||||
* specified by the context and the direction.
|
||||
*/
|
||||
int ext4_fname_crypto_alloc_buffer(struct ext4_fname_crypto_ctx *ctx,
|
||||
u32 ilen, struct ext4_str *crypto_str)
|
||||
{
|
||||
unsigned int olen;
|
||||
|
||||
if (!ctx)
|
||||
return -EIO;
|
||||
olen = ext4_fname_crypto_round_up(ilen, EXT4_CRYPTO_BLOCK_SIZE);
|
||||
crypto_str->len = olen;
|
||||
if (olen < EXT4_FNAME_CRYPTO_DIGEST_SIZE*2)
|
||||
olen = EXT4_FNAME_CRYPTO_DIGEST_SIZE*2;
|
||||
/* Allocated buffer can hold one more character to null-terminate the
|
||||
* string */
|
||||
crypto_str->name = kmalloc(olen+1, GFP_NOFS);
|
||||
if (!(crypto_str->name))
|
||||
return -ENOMEM;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_crypto_free_buffer() -
|
||||
*
|
||||
* Frees the buffer allocated for crypto operation.
|
||||
*/
|
||||
void ext4_fname_crypto_free_buffer(struct ext4_str *crypto_str)
|
||||
{
|
||||
if (!crypto_str)
|
||||
return;
|
||||
kfree(crypto_str->name);
|
||||
crypto_str->name = NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_disk_to_usr() - converts a filename from disk space to user space
|
||||
*/
|
||||
int _ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct ext4_str *iname,
|
||||
struct ext4_str *oname)
|
||||
{
|
||||
if (ctx == NULL)
|
||||
return -EIO;
|
||||
if (iname->len < 3) {
|
||||
/*Check for . and .. */
|
||||
if (iname->name[0] == '.' && iname->name[iname->len-1] == '.') {
|
||||
oname->name[0] = '.';
|
||||
oname->name[iname->len-1] = '.';
|
||||
oname->len = iname->len;
|
||||
return oname->len;
|
||||
}
|
||||
}
|
||||
if (ctx->has_valid_key)
|
||||
return ext4_fname_decrypt(ctx, iname, oname);
|
||||
else
|
||||
return ext4_fname_hash(ctx, iname, oname);
|
||||
}
|
||||
|
||||
int ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct ext4_dir_entry_2 *de,
|
||||
struct ext4_str *oname)
|
||||
{
|
||||
struct ext4_str iname = {.name = (unsigned char *) de->name,
|
||||
.len = de->name_len };
|
||||
|
||||
return _ext4_fname_disk_to_usr(ctx, &iname, oname);
|
||||
}
|
||||
|
||||
|
||||
/**
|
||||
* ext4_fname_usr_to_disk() - converts a filename from user space to disk space
|
||||
*/
|
||||
int ext4_fname_usr_to_disk(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct qstr *iname,
|
||||
struct ext4_str *oname)
|
||||
{
|
||||
int res;
|
||||
|
||||
if (ctx == NULL)
|
||||
return -EIO;
|
||||
if (iname->len < 3) {
|
||||
/*Check for . and .. */
|
||||
if (iname->name[0] == '.' &&
|
||||
iname->name[iname->len-1] == '.') {
|
||||
oname->name[0] = '.';
|
||||
oname->name[iname->len-1] = '.';
|
||||
oname->len = iname->len;
|
||||
return oname->len;
|
||||
}
|
||||
}
|
||||
if (ctx->has_valid_key) {
|
||||
res = ext4_fname_encrypt(ctx, iname, oname);
|
||||
return res;
|
||||
}
|
||||
/* Without a proper key, a user is not allowed to modify the filenames
|
||||
* in a directory. Consequently, a user space name cannot be mapped to
|
||||
* a disk-space name */
|
||||
return -EACCES;
|
||||
}
|
||||
|
||||
/*
|
||||
* Calculate the htree hash from a filename from user space
|
||||
*/
|
||||
int ext4_fname_usr_to_hash(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct qstr *iname,
|
||||
struct dx_hash_info *hinfo)
|
||||
{
|
||||
struct ext4_str tmp, tmp2;
|
||||
int ret = 0;
|
||||
|
||||
if (!ctx || !ctx->has_valid_key ||
|
||||
((iname->name[0] == '.') &&
|
||||
((iname->len == 1) ||
|
||||
((iname->name[1] == '.') && (iname->len == 2))))) {
|
||||
ext4fs_dirhash(iname->name, iname->len, hinfo);
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* First encrypt the plaintext name */
|
||||
ret = ext4_fname_crypto_alloc_buffer(ctx, iname->len, &tmp);
|
||||
if (ret < 0)
|
||||
return ret;
|
||||
|
||||
ret = ext4_fname_encrypt(ctx, iname, &tmp);
|
||||
if (ret < 0)
|
||||
goto out;
|
||||
|
||||
tmp2.len = (4 * ((EXT4_FNAME_CRYPTO_DIGEST_SIZE + 2) / 3)) + 1;
|
||||
tmp2.name = kmalloc(tmp2.len + 1, GFP_KERNEL);
|
||||
if (tmp2.name == NULL) {
|
||||
ret = -ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
|
||||
ret = ext4_fname_hash(ctx, &tmp, &tmp2);
|
||||
if (ret > 0)
|
||||
ext4fs_dirhash(tmp2.name, tmp2.len, hinfo);
|
||||
ext4_fname_crypto_free_buffer(&tmp2);
|
||||
out:
|
||||
ext4_fname_crypto_free_buffer(&tmp);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
* ext4_fname_disk_to_htree() - converts a filename from disk space to htree-access string
|
||||
*/
|
||||
int ext4_fname_disk_to_hash(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct ext4_dir_entry_2 *de,
|
||||
struct dx_hash_info *hinfo)
|
||||
{
|
||||
struct ext4_str iname = {.name = (unsigned char *) de->name,
|
||||
.len = de->name_len};
|
||||
struct ext4_str tmp;
|
||||
int ret;
|
||||
|
||||
if (!ctx ||
|
||||
((iname.name[0] == '.') &&
|
||||
((iname.len == 1) ||
|
||||
((iname.name[1] == '.') && (iname.len == 2))))) {
|
||||
ext4fs_dirhash(iname.name, iname.len, hinfo);
|
||||
return 0;
|
||||
}
|
||||
|
||||
tmp.len = (4 * ((EXT4_FNAME_CRYPTO_DIGEST_SIZE + 2) / 3)) + 1;
|
||||
tmp.name = kmalloc(tmp.len + 1, GFP_KERNEL);
|
||||
if (tmp.name == NULL)
|
||||
return -ENOMEM;
|
||||
|
||||
ret = ext4_fname_hash(ctx, &iname, &tmp);
|
||||
if (ret > 0)
|
||||
ext4fs_dirhash(tmp.name, tmp.len, hinfo);
|
||||
ext4_fname_crypto_free_buffer(&tmp);
|
||||
return ret;
|
||||
}
|
||||
@ -59,6 +59,13 @@ static int ext4_create_encryption_context_from_policy(
|
||||
res = -EINVAL;
|
||||
goto out;
|
||||
}
|
||||
if (!ext4_valid_filenames_enc_mode(policy->filenames_encryption_mode)) {
|
||||
printk(KERN_WARNING
|
||||
"%s: Invalid filenames encryption mode %d\n", __func__,
|
||||
policy->filenames_encryption_mode);
|
||||
res = -EINVAL;
|
||||
goto out;
|
||||
}
|
||||
ctx.contents_encryption_mode = policy->contents_encryption_mode;
|
||||
ctx.filenames_encryption_mode = policy->filenames_encryption_mode;
|
||||
BUILD_BUG_ON(sizeof(ctx.nonce) != EXT4_KEY_DERIVATION_NONCE_SIZE);
|
||||
|
||||
@ -2078,6 +2078,47 @@ static inline int ext4_sb_has_crypto(struct super_block *sb)
|
||||
}
|
||||
#endif
|
||||
|
||||
/* crypto_fname.c */
|
||||
bool ext4_valid_filenames_enc_mode(uint32_t mode);
|
||||
u32 ext4_fname_crypto_round_up(u32 size, u32 blksize);
|
||||
int ext4_fname_crypto_alloc_buffer(struct ext4_fname_crypto_ctx *ctx,
|
||||
u32 ilen, struct ext4_str *crypto_str);
|
||||
int _ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct ext4_str *iname,
|
||||
struct ext4_str *oname);
|
||||
int ext4_fname_disk_to_usr(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct ext4_dir_entry_2 *de,
|
||||
struct ext4_str *oname);
|
||||
int ext4_fname_usr_to_disk(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct qstr *iname,
|
||||
struct ext4_str *oname);
|
||||
int ext4_fname_usr_to_hash(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct qstr *iname,
|
||||
struct dx_hash_info *hinfo);
|
||||
int ext4_fname_disk_to_hash(struct ext4_fname_crypto_ctx *ctx,
|
||||
const struct ext4_dir_entry_2 *de,
|
||||
struct dx_hash_info *hinfo);
|
||||
int ext4_fname_crypto_namelen_on_disk(struct ext4_fname_crypto_ctx *ctx,
|
||||
u32 namelen);
|
||||
|
||||
#ifdef CONFIG_EXT4_FS_ENCRYPTION
|
||||
void ext4_put_fname_crypto_ctx(struct ext4_fname_crypto_ctx **ctx);
|
||||
struct ext4_fname_crypto_ctx *ext4_get_fname_crypto_ctx(struct inode *inode,
|
||||
u32 max_len);
|
||||
void ext4_fname_crypto_free_buffer(struct ext4_str *crypto_str);
|
||||
#else
|
||||
static inline
|
||||
void ext4_put_fname_crypto_ctx(struct ext4_fname_crypto_ctx **ctx) { }
|
||||
static inline
|
||||
struct ext4_fname_crypto_ctx *ext4_get_fname_crypto_ctx(struct inode *inode,
|
||||
u32 max_len)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
static inline void ext4_fname_crypto_free_buffer(struct ext4_str *p) { }
|
||||
#endif
|
||||
|
||||
|
||||
/* crypto_key.c */
|
||||
int ext4_generate_encryption_key(struct inode *inode);
|
||||
|
||||
|
||||
@ -104,4 +104,24 @@ static inline int ext4_encryption_key_size(int mode)
|
||||
return 0;
|
||||
}
|
||||
|
||||
#define EXT4_FNAME_NUM_SCATTER_ENTRIES 4
|
||||
#define EXT4_CRYPTO_BLOCK_SIZE 16
|
||||
#define EXT4_FNAME_CRYPTO_DIGEST_SIZE 32
|
||||
|
||||
struct ext4_str {
|
||||
unsigned char *name;
|
||||
u32 len;
|
||||
};
|
||||
|
||||
struct ext4_fname_crypto_ctx {
|
||||
u32 lim;
|
||||
char tmp_buf[EXT4_CRYPTO_BLOCK_SIZE];
|
||||
struct crypto_ablkcipher *ctfm;
|
||||
struct crypto_hash *htfm;
|
||||
struct page *workpage;
|
||||
struct ext4_encryption_key key;
|
||||
unsigned has_valid_key : 1;
|
||||
unsigned ctfm_key_is_ready : 1;
|
||||
};
|
||||
|
||||
#endif /* _EXT4_CRYPTO_H */
|
||||
|
||||
Loading…
Reference in New Issue
Block a user