path: root/security/keys/trusted-keys/trusted_tpm1.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2010 IBM Corporation
 * Copyright (c) 2019-2021, Linaro Limited
 *
 * See Documentation/security/keys/trusted-encrypted.rst
 */

#include <crypto/hash_info.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/parser.h>
#include <linux/string.h>
#include <linux/err.h>
#include <keys/trusted-type.h>
#include <linux/key-type.h>
#include <linux/crypto.h>
#include <crypto/hash.h>
#include <crypto/sha1.h>
#include <linux/tpm.h>
#include <linux/tpm_command.h>

#include <keys/trusted_tpm.h>

static const char hmac_alg[] = "hmac(sha1)";
static const char hash_alg[] = "sha1";
static struct tpm_chip *chip;
static struct tpm_digest *digests;

struct sdesc {
	struct shash_desc shash;
	char ctx[];
};

static struct crypto_shash *hashalg;
static struct crypto_shash *hmacalg;

static struct sdesc *init_sdesc(struct crypto_shash *alg)
{
	struct sdesc *sdesc;
	int size;

	size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
	sdesc = kmalloc(size, GFP_KERNEL);
	if (!sdesc)
		return ERR_PTR(-ENOMEM);
	sdesc->shash.tfm = alg;
	return sdesc;
}

static int TSS_sha1(const unsigned char *data, unsigned int datalen,
		    unsigned char *digest)
{
	struct sdesc *sdesc;
	int ret;

	sdesc = init_sdesc(hashalg);
	if (IS_ERR(sdesc)) {
		pr_info("can't alloc %s\n", hash_alg);
		return PTR_ERR(sdesc);
	}

	ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
	kfree_sensitive(sdesc);
	return ret;
}

static int TSS_rawhmac(unsigned char *digest, const unsigned char *key,
		       unsigned int keylen, ...)
{
	struct sdesc *sdesc;
	va_list argp;
	unsigned int dlen;
	unsigned char *data;
	int ret;

	sdesc = init_sdesc(hmacalg);
	if (IS_ERR(sdesc)) {
		pr_info("can't alloc %s\n", hmac_alg);
		return PTR_ERR(sdesc);
	}

	ret = crypto_shash_setkey(hmacalg, key, keylen);
	if (ret < 0)
		goto out;
	ret = crypto_shash_init(&sdesc->shash);
	if (ret < 0)
		goto out;

	va_start(argp, keylen);
	for (;;) {
		dlen = va_arg(argp, unsigned int);
		if (dlen == 0)
			break;
		data = va_arg(argp, unsigned char *);
		if (data == NULL) {
			ret = -EINVAL;
			break;
		}
		ret = crypto_shash_update(&sdesc->shash, data, dlen);
		if (ret < 0)
			break;
	}
	va_end(argp);
	if (!ret)
		ret = crypto_shash_final(&sdesc->shash, digest);
out:
	kfree_sensitive(sdesc);
	return ret;
}

/*
 * calculate authorization info fields to send to TPM
 */
int TSS_authhmac(unsigned char *digest, const unsigned char *key,
			unsigned int keylen, unsigned char *h1,
			unsigned char *h2, unsigned int h3, ...)
{
	unsigned char paramdigest[SHA1_DIGEST_SIZE];
	struct sdesc *sdesc;
	unsigned int dlen;
	unsigned char *data;
	unsigned char c;
	int ret;
	va_list argp;

	if (!chip)
		return -ENODEV;

	sdesc = init_sdesc(hashalg);
	if (IS_ERR(sdesc)) {
		pr_info("can't alloc %s\n", hash_alg);
		return PTR_ERR(sdesc);
	}

	c = !!h3;
	ret = crypto_shash_init(&sdesc->shash);
	if (ret < 0)
		goto out;
	va_start(argp, h3);
	for (;;) {
		dlen = va_arg(argp, unsigned int);
		if (dlen == 0)
			break;
		data = va_arg(argp, unsigned char *);
		if (!data) {
			ret = -EINVAL;
			break;
		}
		ret = crypto_shash_update(&sdesc->shash, data, dlen);
		if (ret < 0)
			break;
	}
	va_end(argp);
	if (!ret)
		ret = crypto_shash_final(&sdesc->shash, paramdigest);
	if (!ret)
		ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
				  paramdigest, TPM_NONCE_SIZE, h1,
				  TPM_NONCE_SIZE, h2, 1,