149 lines
3.0 KiB
C
149 lines
3.0 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
|
|
*/
|
|
|
|
#include <linux/kernel.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 "ima.h"
|
|
|
|
static struct crypto_shash *ima_shash_tfm;
|
|
|
|
int ima_init_crypto(void)
|
|
{
|
|
long rc;
|
|
|
|
ima_shash_tfm = crypto_alloc_shash(ima_hash, 0, 0);
|
|
if (IS_ERR(ima_shash_tfm)) {
|
|
rc = PTR_ERR(ima_shash_tfm);
|
|
pr_err("Can not allocate %s (reason: %ld)\n", ima_hash, rc);
|
|
return rc;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Calculate the MD5/SHA1 file digest
|
|
*/
|
|
int ima_calc_file_hash(struct file *file, char *digest)
|
|
{
|
|
loff_t i_size, offset = 0;
|
|
char *rbuf;
|
|
int rc, read = 0;
|
|
struct {
|
|
struct shash_desc shash;
|
|
char ctx[crypto_shash_descsize(ima_shash_tfm)];
|
|
} desc;
|
|
|
|
desc.shash.tfm = ima_shash_tfm;
|
|
desc.shash.flags = 0;
|
|
|
|
rc = crypto_shash_init(&desc.shash);
|
|
if (rc != 0)
|
|
return rc;
|
|
|
|
rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
|
|
if (!rbuf) {
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
if (!(file->f_mode & FMODE_READ)) {
|
|
file->f_mode |= FMODE_READ;
|
|
read = 1;
|
|
}
|
|
i_size = i_size_read(file_inode(file));
|
|
while (offset < i_size) {
|
|
int rbuf_len;
|
|
|
|
rbuf_len = 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;
|
|
}
|
|
kfree(rbuf);
|
|
if (!rc)
|
|
rc = crypto_shash_final(&desc.shash, digest);
|
|
if (read)
|
|
file->f_mode &= ~FMODE_READ;
|
|
out:
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* Calculate the hash of a given buffer
|
|
*/
|
|
int ima_calc_buffer_hash(const void *data, int len, char *digest)
|
|
{
|
|
struct {
|
|
struct shash_desc shash;
|
|
char ctx[crypto_shash_descsize(ima_shash_tfm)];
|
|
} desc;
|
|
|
|
desc.shash.tfm = ima_shash_tfm;
|
|
desc.shash.flags = 0;
|
|
|
|
return crypto_shash_digest(&desc.shash, data, len, digest);
|
|
}
|
|
|
|
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("IMA: Error Communicating to TPM chip\n");
|
|
}
|
|
|
|
/*
|
|
* Calculate the boot aggregate hash
|
|
*/
|
|
int __init ima_calc_boot_aggregate(char *digest)
|
|
{
|
|
u8 pcr_i[IMA_DIGEST_SIZE];
|
|
int rc, i;
|
|
struct {
|
|
struct shash_desc shash;
|
|
char ctx[crypto_shash_descsize(ima_shash_tfm)];
|
|
} desc;
|
|
|
|
desc.shash.tfm = ima_shash_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, IMA_DIGEST_SIZE);
|
|
}
|
|
if (!rc)
|
|
crypto_shash_final(&desc.shash, digest);
|
|
return rc;
|
|
}
|