[net-next-2.6.git] / security / integrity / ima / ima_crypto.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 "ima.h"

static int init_desc(struct hash_desc *desc)
{
	int rc;

	desc->tfm = crypto_alloc_hash(ima_hash, 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(desc->tfm)) {
		pr_info("failed to load %s transform: %ld\n",
			ima_hash, PTR_ERR(desc->tfm));
		rc = PTR_ERR(desc->tfm);
		return rc;
	}
	desc->flags = 0;
	rc = crypto_hash_init(desc);
	if (rc)
		crypto_free_hash(desc->tfm);
	return rc;
}

/*
 * Calculate the MD5/SHA1 file digest
 */
int ima_calc_hash(struct file *file, char *digest)
{
	struct hash_desc desc;
	struct scatterlist sg[1];
	loff_t i_size, offset = 0;
	char *rbuf;
	int rc;

	rc = init_desc(&desc);
	if (rc != 0)
		return rc;

	rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	if (!rbuf) {
		rc = -ENOMEM;
		goto out;
	}
	i_size = i_size_read(file->f_dentry->d_inode);
	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;
		sg_init_one(sg, rbuf, rbuf_len);

		rc = crypto_hash_update(&desc, sg, rbuf_len);
		if (rc)
			break;
	}
	kfree(rbuf);
	if (!rc)
		rc = crypto_hash_final(&desc, digest);
out:
	crypto_free_hash(desc.tfm);
	return rc;
}

/*
 * Calculate the hash of a given template
 */
int ima_calc_template_hash(int template_len, void *template, char *digest)
{
	struct hash_desc desc;
	struct scatterlist sg[1];
	int rc;

	rc = init_desc(&desc);
	if (rc != 0)
		return rc;

	sg_init_one(sg, template, template_len);
	rc = crypto_hash_update(&desc, sg, template_len);
	if (!rc)
		rc = crypto_hash_final(&desc, digest);
	crypto_free_hash(desc.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
 */
int __init ima_calc_boot_aggregate(char *digest)
{
	struct hash_desc desc;
	struct scatterlist sg;
	u8 pcr_i[IMA_DIGEST_SIZE];
	int rc, i;

	rc = init_desc(&desc);
	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 */
		sg_init_one(&sg, pcr_i, IMA_DIGEST_SIZE);
		rc = crypto_hash_update(&desc, &sg, IMA_DIGEST_SIZE);
	}
	if (!rc)
		crypto_hash_final(&desc, digest);
	crypto_free_hash(desc.tfm);
	return rc;
}
Commit	Line	Data
3323eec9 MZ	1	/*
	2	* Copyright (C) 2005,2006,2007,2008 IBM Corporation
	3	*
	4	* Authors:
	5	* Mimi Zohar <zohar@us.ibm.com>
	6	* Kylene Hall <kjhall@us.ibm.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License as published by
	10	* the Free Software Foundation, version 2 of the License.
	11	*
	12	* File: ima_crypto.c
	13	* Calculates md5/sha1 file hash, template hash, boot-aggreate hash
	14	*/
	15
	16	#include <linux/kernel.h>
	17	#include <linux/file.h>
	18	#include <linux/crypto.h>
	19	#include <linux/scatterlist.h>
	20	#include <linux/err.h>
5a0e3ad6	21	#include <linux/slab.h>
3323eec9 MZ	22	#include "ima.h"
	23
	24	static int init_desc(struct hash_desc *desc)
	25	{
	26	int rc;
	27
	28	desc->tfm = crypto_alloc_hash(ima_hash, 0, CRYPTO_ALG_ASYNC);
	29	if (IS_ERR(desc->tfm)) {
	30	pr_info("failed to load %s transform: %ld\n",
	31	ima_hash, PTR_ERR(desc->tfm));
	32	rc = PTR_ERR(desc->tfm);
	33	return rc;
	34	}
	35	desc->flags = 0;
	36	rc = crypto_hash_init(desc);
	37	if (rc)
	38	crypto_free_hash(desc->tfm);
	39	return rc;
	40	}
	41
	42	/*
	43	* Calculate the MD5/SHA1 file digest
	44	*/
	45	int ima_calc_hash(struct file file, char digest)
	46	{
	47	struct hash_desc desc;
	48	struct scatterlist sg[1];
16bfa38b	49	loff_t i_size, offset = 0;
3323eec9	50	char *rbuf;
16bfa38b	51	int rc;
3323eec9 MZ	52
	53	rc = init_desc(&desc);
	54	if (rc != 0)
	55	return rc;
	56
	57	rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
	58	if (!rbuf) {
	59	rc = -ENOMEM;
	60	goto out;
	61	}
	62	i_size = i_size_read(file->f_dentry->d_inode);
	63	while (offset < i_size) {
	64	int rbuf_len;
	65
	66	rbuf_len = kernel_read(file, offset, rbuf, PAGE_SIZE);
	67	if (rbuf_len < 0) {
	68	rc = rbuf_len;
	69	break;
	70	}
16bfa38b MZ	71	if (rbuf_len == 0)
16bfa38b MZ	72	break;
3323eec9	73	offset += rbuf_len;
0da0a420	74	sg_init_one(sg, rbuf, rbuf_len);
3323eec9 MZ	75
	76	rc = crypto_hash_update(&desc, sg, rbuf_len);
	77	if (rc)
	78	break;
	79	}
	80	kfree(rbuf);
	81	if (!rc)
	82	rc = crypto_hash_final(&desc, digest);
	83	out:
	84	crypto_free_hash(desc.tfm);
	85	return rc;
	86	}
	87
	88	/*
	89	* Calculate the hash of a given template
	90	*/
	91	int ima_calc_template_hash(int template_len, void template, char digest)
	92	{
	93	struct hash_desc desc;
	94	struct scatterlist sg[1];
	95	int rc;
	96
	97	rc = init_desc(&desc);
	98	if (rc != 0)
	99	return rc;
	100
0da0a420	101	sg_init_one(sg, template, template_len);
3323eec9 MZ	102	rc = crypto_hash_update(&desc, sg, template_len);
	103	if (!rc)
	104	rc = crypto_hash_final(&desc, digest);
	105	crypto_free_hash(desc.tfm);
	106	return rc;
	107	}
	108
932995f0	109	static void __init ima_pcrread(int idx, u8 *pcr)
3323eec9 MZ	110	{
	111	if (!ima_used_chip)
	112	return;
	113
	114	if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
	115	pr_err("Error Communicating to TPM chip\n");
	116	}
	117
	118	/*
	119	* Calculate the boot aggregate hash
	120	*/
932995f0	121	int __init ima_calc_boot_aggregate(char *digest)
3323eec9 MZ	122	{
	123	struct hash_desc desc;
	124	struct scatterlist sg;
	125	u8 pcr_i[IMA_DIGEST_SIZE];
	126	int rc, i;
	127
	128	rc = init_desc(&desc);
	129	if (rc != 0)
	130	return rc;
	131
	132	/* cumulative sha1 over tpm registers 0-7 */
	133	for (i = TPM_PCR0; i < TPM_PCR8; i++) {
	134	ima_pcrread(i, pcr_i);
	135	/* now accumulate with current aggregate */
	136	sg_init_one(&sg, pcr_i, IMA_DIGEST_SIZE);
	137	rc = crypto_hash_update(&desc, &sg, IMA_DIGEST_SIZE);
	138	}
	139	if (!rc)
	140	crypto_hash_final(&desc, digest);
	141	crypto_free_hash(desc.tfm);
	142	return rc;
	143	}