![Dmitry Kasatkin](/assets/img/avatar_default.png)
The asynchronous hash API allows initiating a hash calculation and then performing other tasks, while waiting for the hash calculation to complete. This patch introduces usage of double buffering for simultaneous hashing and reading of the next chunk of data from storage. Changes in v3: - better comments Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
607 lines
14 KiB
C
607 lines
14 KiB
C
/*
|
|
* Copyright (C) 2005,2006,2007,2008 IBM Corporation
|
|
*
|
|
* Authors:
|
|
* Mimi Zohar <zohar@us.ibm.com>
|
|
* Kylene Hall <kjhall@us.ibm.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, version 2 of the License.
|
|
*
|
|
* File: ima_crypto.c
|
|
* Calculates md5/sha1 file hash, template hash, boot-aggreate hash
|
|
*/
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/ratelimit.h>
|
|
#include <linux/file.h>
|
|
#include <linux/crypto.h>
|
|
#include <linux/scatterlist.h>
|
|
#include <linux/err.h>
|
|
#include <linux/slab.h>
|
|
#include <crypto/hash.h>
|
|
#include <crypto/hash_info.h>
|
|
#include "ima.h"
|
|
|
|
struct ahash_completion {
|
|
struct completion completion;
|
|
int err;
|
|
};
|
|
|
|
/* minimum file size for ahash use */
|
|
static unsigned long ima_ahash_minsize;
|
|
module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644);
|
|
MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use");
|
|
|
|
/* default is 0 - 1 page. */
|
|
static int ima_maxorder;
|
|
static unsigned int ima_bufsize = PAGE_SIZE;
|
|
|
|
static int param_set_bufsize(const char *val, const struct kernel_param *kp)
|
|
{
|
|
unsigned long long size;
|
|
int order;
|
|
|
|
size = memparse(val, NULL);
|
|
order = get_order(size);
|
|
if (order >= MAX_ORDER)
|
|
return -EINVAL;
|
|
ima_maxorder = order;
|
|
ima_bufsize = PAGE_SIZE << order;
|
|
return 0;
|
|
}
|
|
|
|
static struct kernel_param_ops param_ops_bufsize = {
|
|
.set = param_set_bufsize,
|
|
.get = param_get_uint,
|
|
};
|
|
#define param_check_bufsize(name, p) __param_check(name, p, unsigned int)
|
|
|
|
module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644);
|
|
MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size");
|
|
|
|
static struct crypto_shash *ima_shash_tfm;
|
|
static struct crypto_ahash *ima_ahash_tfm;
|
|
|
|
/**
|
|
* ima_kernel_read - read file content
|
|
*
|
|
* This is a function for reading file content instead of kernel_read().
|
|
* It does not perform locking checks to ensure it cannot be blocked.
|
|
* It does not perform security checks because it is irrelevant for IMA.
|
|
*
|
|
*/
|
|
static int ima_kernel_read(struct file *file, loff_t offset,
|
|
char *addr, unsigned long count)
|
|
{
|
|
mm_segment_t old_fs;
|
|
char __user *buf = addr;
|
|
ssize_t ret;
|
|
|
|
if (!(file->f_mode & FMODE_READ))
|
|
return -EBADF;
|
|
if (!file->f_op->read && !file->f_op->aio_read)
|
|
return -EINVAL;
|
|
|
|
old_fs = get_fs();
|
|
set_fs(get_ds());
|
|
if (file->f_op->read)
|
|
ret = file->f_op->read(file, buf, count, &offset);
|
|
else
|
|
ret = do_sync_read(file, buf, count, &offset);
|
|
set_fs(old_fs);
|
|
return ret;
|
|
}
|
|
|
|
int ima_init_crypto(void)
|
|
{
|
|
long rc;
|
|
|
|
ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0);
|
|
if (IS_ERR(ima_shash_tfm)) {
|
|
rc = PTR_ERR(ima_shash_tfm);
|
|
pr_err("Can not allocate %s (reason: %ld)\n",
|
|
hash_algo_name[ima_hash_algo], rc);
|
|
return rc;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo)
|
|
{
|
|
struct crypto_shash *tfm = ima_shash_tfm;
|
|
int rc;
|
|
|
|
if (algo != ima_hash_algo && algo < HASH_ALGO__LAST) {
|
|
tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0);
|
|
if (IS_ERR(tfm)) {
|
|
rc = PTR_ERR(tfm);
|
|
pr_err("Can not allocate %s (reason: %d)\n",
|
|
hash_algo_name[algo], rc);
|
|
}
|
|
}
|
|
return tfm;
|
|
}
|
|
|
|
static void ima_free_tfm(struct crypto_shash *tfm)
|
|
{
|
|
if (tfm != ima_shash_tfm)
|
|
crypto_free_shash(tfm);
|
|
}
|
|
|
|
/**
|
|
* ima_alloc_pages() - Allocate contiguous pages.
|
|
* @max_size: Maximum amount of memory to allocate.
|
|
* @allocated_size: Returned size of actual allocation.
|
|
* @last_warn: Should the min_size allocation warn or not.
|
|
*
|
|
* Tries to do opportunistic allocation for memory first trying to allocate
|
|
* max_size amount of memory and then splitting that until zero order is
|
|
* reached. Allocation is tried without generating allocation warnings unless
|
|
* last_warn is set. Last_warn set affects only last allocation of zero order.
|
|
*
|
|
* By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL)
|
|
*
|
|
* Return pointer to allocated memory, or NULL on failure.
|
|
*/
|
|
static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size,
|
|
int last_warn)
|
|
{
|
|
void *ptr;
|
|
int order = ima_maxorder;
|
|
gfp_t gfp_mask = __GFP_WAIT | __GFP_NOWARN | __GFP_NORETRY;
|
|
|
|
if (order)
|
|
order = min(get_order(max_size), order);
|
|
|
|
for (; order; order--) {
|
|
ptr = (void *)__get_free_pages(gfp_mask, order);
|
|
if (ptr) {
|
|
*allocated_size = PAGE_SIZE << order;
|
|
return ptr;
|
|
}
|
|
}
|
|
|
|
/* order is zero - one page */
|
|
|
|
gfp_mask = GFP_KERNEL;
|
|
|
|
if (!last_warn)
|
|
gfp_mask |= __GFP_NOWARN;
|
|
|
|
ptr = (void *)__get_free_pages(gfp_mask, 0);
|
|
if (ptr) {
|
|
*allocated_size = PAGE_SIZE;
|
|
return ptr;
|
|
}
|
|
|
|
*allocated_size = 0;
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* ima_free_pages() - Free pages allocated by ima_alloc_pages().
|
|
* @ptr: Pointer to allocated pages.
|
|
* @size: Size of allocated buffer.
|
|
*/
|
|
static void ima_free_pages(void *ptr, size_t size)
|
|
{
|
|
if (!ptr)
|
|
return;
|
|
free_pages((unsigned long)ptr, get_order(size));
|
|
}
|
|
|
|
static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo)
|
|
{
|
|
struct crypto_ahash *tfm = ima_ahash_tfm;
|
|
int rc;
|
|
|
|
if ((algo != ima_hash_algo && algo < HASH_ALGO__LAST) || !tfm) {
|
|
tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0);
|
|
if (!IS_ERR(tfm)) {
|
|
if (algo == ima_hash_algo)
|
|
ima_ahash_tfm = tfm;
|
|
} else {
|
|
rc = PTR_ERR(tfm);
|
|
pr_err("Can not allocate %s (reason: %d)\n",
|
|
hash_algo_name[algo], rc);
|
|
}
|
|
}
|
|
return tfm;
|
|
}
|
|
|
|
static void ima_free_atfm(struct crypto_ahash *tfm)
|
|
{
|
|
if (tfm != ima_ahash_tfm)
|
|
crypto_free_ahash(tfm);
|
|
}
|
|
|
|
static void ahash_complete(struct crypto_async_request *req, int err)
|
|
{
|
|
struct ahash_completion *res = req->data;
|
|
|
|
if (err == -EINPROGRESS)
|
|
return;
|
|
res->err = err;
|
|
complete(&res->completion);
|
|
}
|
|
|
|
static int ahash_wait(int err, struct ahash_completion *res)
|
|
{
|
|
switch (err) {
|
|
case 0:
|
|
break;
|
|
case -EINPROGRESS:
|
|
case -EBUSY:
|
|
wait_for_completion(&res->completion);
|
|
reinit_completion(&res->completion);
|
|
err = res->err;
|
|
/* fall through */
|
|
default:
|
|
pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int ima_calc_file_hash_atfm(struct file *file,
|
|
struct ima_digest_data *hash,
|
|
struct crypto_ahash *tfm)
|
|
{
|
|
loff_t i_size, offset;
|
|
char *rbuf[2] = { NULL, };
|
|
int rc, read = 0, rbuf_len, active = 0, ahash_rc = 0;
|
|
struct ahash_request *req;
|
|
struct scatterlist sg[1];
|
|
struct ahash_completion res;
|
|
size_t rbuf_size[2];
|
|
|
|
hash->length = crypto_ahash_digestsize(tfm);
|
|
|
|
req = ahash_request_alloc(tfm, GFP_KERNEL);
|
|
if (!req)
|
|
return -ENOMEM;
|
|
|
|
init_completion(&res.completion);
|
|
ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
|
|
CRYPTO_TFM_REQ_MAY_SLEEP,
|
|
ahash_complete, &res);
|
|
|
|
rc = ahash_wait(crypto_ahash_init(req), &res);
|
|
if (rc)
|
|
goto out1;
|
|
|
|
i_size = i_size_read(file_inode(file));
|
|
|
|
if (i_size == 0)
|
|
goto out2;
|
|
|
|
/*
|
|
* Try to allocate maximum size of memory.
|
|
* Fail if even a single page cannot be allocated.
|
|
*/
|
|
rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1);
|
|
if (!rbuf[0]) {
|
|
rc = -ENOMEM;
|
|
goto out1;
|
|
}
|
|
|
|
/* Only allocate one buffer if that is enough. */
|
|
if (i_size > rbuf_size[0]) {
|
|
/*
|
|
* Try to allocate secondary buffer. If that fails fallback to
|
|
* using single buffering. Use previous memory allocation size
|
|
* as baseline for possible allocation size.
|
|
*/
|
|
rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0],
|
|
&rbuf_size[1], 0);
|
|
}
|
|
|
|
if (!(file->f_mode & FMODE_READ)) {
|
|
file->f_mode |= FMODE_READ;
|
|
read = 1;
|
|
}
|
|
|
|
for (offset = 0; offset < i_size; offset += rbuf_len) {
|
|
if (!rbuf[1] && offset) {
|
|
/* Not using two buffers, and it is not the first
|
|
* read/request, wait for the completion of the
|
|
* previous ahash_update() request.
|
|
*/
|
|
rc = ahash_wait(ahash_rc, &res);
|
|
if (rc)
|
|
goto out3;
|
|
}
|
|
/* read buffer */
|
|
rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]);
|
|
rc = ima_kernel_read(file, offset, rbuf[active], rbuf_len);
|
|
if (rc != rbuf_len)
|
|
goto out3;
|
|
|
|
if (rbuf[1] && offset) {
|
|
/* Using two buffers, and it is not the first
|
|
* read/request, wait for the completion of the
|
|
* previous ahash_update() request.
|
|
*/
|
|
rc = ahash_wait(ahash_rc, &res);
|
|
if (rc)
|
|
goto out3;
|
|
}
|
|
|
|
sg_init_one(&sg[0], rbuf[active], rbuf_len);
|
|
ahash_request_set_crypt(req, sg, NULL, rbuf_len);
|
|
|
|
ahash_rc = crypto_ahash_update(req);
|
|
|
|
if (rbuf[1])
|
|
active = !active; /* swap buffers, if we use two */
|
|
}
|
|
/* wait for the last update request to complete */
|
|
rc = ahash_wait(ahash_rc, &res);
|
|
out3:
|
|
if (read)
|
|
file->f_mode &= ~FMODE_READ;
|
|
ima_free_pages(rbuf[0], rbuf_size[0]);
|
|
ima_free_pages(rbuf[1], rbuf_size[1]);
|
|
out2:
|
|
if (!rc) {
|
|
ahash_request_set_crypt(req, NULL, hash->digest, 0);
|
|
rc = ahash_wait(crypto_ahash_final(req), &res);
|
|
}
|
|
out1:
|
|
ahash_request_free(req);
|
|
return rc;
|
|
}
|
|
|
|
static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash)
|
|
{
|
|
struct crypto_ahash *tfm;
|
|
int rc;
|
|
|
|
tfm = ima_alloc_atfm(hash->algo);
|
|
if (IS_ERR(tfm))
|
|
return PTR_ERR(tfm);
|
|
|
|
rc = ima_calc_file_hash_atfm(file, hash, tfm);
|
|
|
|
ima_free_atfm(tfm);
|
|
|
|
return rc;
|
|
}
|
|
|
|
static int ima_calc_file_hash_tfm(struct file *file,
|
|
struct ima_digest_data *hash,
|
|
struct crypto_shash *tfm)
|
|
{
|
|
loff_t i_size, offset = 0;
|
|
char *rbuf;
|
|
int rc, read = 0;
|
|
struct {
|
|
struct shash_desc shash;
|
|
char ctx[crypto_shash_descsize(tfm)];
|
|
} desc;
|
|
|
|
desc.shash.tfm = tfm;
|
|
desc.shash.flags = 0;
|
|
|
|
hash->length = crypto_shash_digestsize(tfm);
|
|
|
|
rc = crypto_shash_init(&desc.shash);
|
|
if (rc != 0)
|
|
return rc;
|
|
|
|
i_size = i_size_read(file_inode(file));
|
|
|
|
if (i_size == 0)
|
|
goto out;
|
|
|
|
rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
|
|
if (!rbuf)
|
|
return -ENOMEM;
|
|
|
|
if (!(file->f_mode & FMODE_READ)) {
|
|
file->f_mode |= FMODE_READ;
|
|
read = 1;
|
|
}
|
|
|
|
while (offset < i_size) {
|
|
int rbuf_len;
|
|
|
|
rbuf_len = ima_kernel_read(file, offset, rbuf, PAGE_SIZE);
|
|
if (rbuf_len < 0) {
|
|
rc = rbuf_len;
|
|
break;
|
|
}
|
|
if (rbuf_len == 0)
|
|
break;
|
|
offset += rbuf_len;
|
|
|
|
rc = crypto_shash_update(&desc.shash, rbuf, rbuf_len);
|
|
if (rc)
|
|
break;
|
|
}
|
|
if (read)
|
|
file->f_mode &= ~FMODE_READ;
|
|
kfree(rbuf);
|
|
out:
|
|
if (!rc)
|
|
rc = crypto_shash_final(&desc.shash, hash->digest);
|
|
return rc;
|
|
}
|
|
|
|
static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash)
|
|
{
|
|
struct crypto_shash *tfm;
|
|
int rc;
|
|
|
|
tfm = ima_alloc_tfm(hash->algo);
|
|
if (IS_ERR(tfm))
|
|
return PTR_ERR(tfm);
|
|
|
|
rc = ima_calc_file_hash_tfm(file, hash, tfm);
|
|
|
|
ima_free_tfm(tfm);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* ima_calc_file_hash - calculate file hash
|
|
*
|
|
* Asynchronous hash (ahash) allows using HW acceleration for calculating
|
|
* a hash. ahash performance varies for different data sizes on different
|
|
* crypto accelerators. shash performance might be better for smaller files.
|
|
* The 'ima.ahash_minsize' module parameter allows specifying the best
|
|
* minimum file size for using ahash on the system.
|
|
*
|
|
* If the ima.ahash_minsize parameter is not specified, this function uses
|
|
* shash for the hash calculation. If ahash fails, it falls back to using
|
|
* shash.
|
|
*/
|
|
int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash)
|
|
{
|
|
loff_t i_size;
|
|
int rc;
|
|
|
|
i_size = i_size_read(file_inode(file));
|
|
|
|
if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
|
|
rc = ima_calc_file_ahash(file, hash);
|
|
if (!rc)
|
|
return 0;
|
|
}
|
|
|
|
return ima_calc_file_shash(file, hash);
|
|
}
|
|
|
|
/*
|
|
* Calculate the hash of template data
|
|
*/
|
|
static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
|
|
struct ima_template_desc *td,
|
|
int num_fields,
|
|
struct ima_digest_data *hash,
|
|
struct crypto_shash *tfm)
|
|
{
|
|
struct {
|
|
struct shash_desc shash;
|
|
char ctx[crypto_shash_descsize(tfm)];
|
|
} desc;
|
|
int rc, i;
|
|
|
|
desc.shash.tfm = tfm;
|
|
desc.shash.flags = 0;
|
|
|
|
hash->length = crypto_shash_digestsize(tfm);
|
|
|
|
rc = crypto_shash_init(&desc.shash);
|
|
if (rc != 0)
|
|
return rc;
|
|
|
|
for (i = 0; i < num_fields; i++) {
|
|
u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
|
|
u8 *data_to_hash = field_data[i].data;
|
|
u32 datalen = field_data[i].len;
|
|
|
|
if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
|
|
rc = crypto_shash_update(&desc.shash,
|
|
(const u8 *) &field_data[i].len,
|
|
sizeof(field_data[i].len));
|
|
if (rc)
|
|
break;
|
|
} else if (strcmp(td->fields[i]->field_id, "n") == 0) {
|
|
memcpy(buffer, data_to_hash, datalen);
|
|
data_to_hash = buffer;
|
|
datalen = IMA_EVENT_NAME_LEN_MAX + 1;
|
|
}
|
|
rc = crypto_shash_update(&desc.shash, data_to_hash, datalen);
|
|
if (rc)
|
|
break;
|
|
}
|
|
|
|
if (!rc)
|
|
rc = crypto_shash_final(&desc.shash, hash->digest);
|
|
|
|
return rc;
|
|
}
|
|
|
|
int ima_calc_field_array_hash(struct ima_field_data *field_data,
|
|
struct ima_template_desc *desc, int num_fields,
|
|
struct ima_digest_data *hash)
|
|
{
|
|
struct crypto_shash *tfm;
|
|
int rc;
|
|
|
|
tfm = ima_alloc_tfm(hash->algo);
|
|
if (IS_ERR(tfm))
|
|
return PTR_ERR(tfm);
|
|
|
|
rc = ima_calc_field_array_hash_tfm(field_data, desc, num_fields,
|
|
hash, tfm);
|
|
|
|
ima_free_tfm(tfm);
|
|
|
|
return rc;
|
|
}
|
|
|
|
static void __init ima_pcrread(int idx, u8 *pcr)
|
|
{
|
|
if (!ima_used_chip)
|
|
return;
|
|
|
|
if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
|
|
pr_err("Error Communicating to TPM chip\n");
|
|
}
|
|
|
|
/*
|
|
* Calculate the boot aggregate hash
|
|
*/
|
|
static int __init ima_calc_boot_aggregate_tfm(char *digest,
|
|
struct crypto_shash *tfm)
|
|
{
|
|
u8 pcr_i[TPM_DIGEST_SIZE];
|
|
int rc, i;
|
|
struct {
|
|
struct shash_desc shash;
|
|
char ctx[crypto_shash_descsize(tfm)];
|
|
} desc;
|
|
|
|
desc.shash.tfm = tfm;
|
|
desc.shash.flags = 0;
|
|
|
|
rc = crypto_shash_init(&desc.shash);
|
|
if (rc != 0)
|
|
return rc;
|
|
|
|
/* cumulative sha1 over tpm registers 0-7 */
|
|
for (i = TPM_PCR0; i < TPM_PCR8; i++) {
|
|
ima_pcrread(i, pcr_i);
|
|
/* now accumulate with current aggregate */
|
|
rc = crypto_shash_update(&desc.shash, pcr_i, TPM_DIGEST_SIZE);
|
|
}
|
|
if (!rc)
|
|
crypto_shash_final(&desc.shash, digest);
|
|
return rc;
|
|
}
|
|
|
|
int __init ima_calc_boot_aggregate(struct ima_digest_data *hash)
|
|
{
|
|
struct crypto_shash *tfm;
|
|
int rc;
|
|
|
|
tfm = ima_alloc_tfm(hash->algo);
|
|
if (IS_ERR(tfm))
|
|
return PTR_ERR(tfm);
|
|
|
|
hash->length = crypto_shash_digestsize(tfm);
|
|
rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm);
|
|
|
|
ima_free_tfm(tfm);
|
|
|
|
return rc;
|
|
}
|