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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright(c) 2024-2005 Intel Corporation. All rights reserved. */
#define pr_fmt(x) KBUILD_MODNAME ": " x
#include <linux/module.h>
#include <linux/tsm-mr.h>
#include <linux/miscdevice.h>
#include <crypto/sha2.h>
static struct {
u8 static_mr[SHA384_DIGEST_SIZE];
u8 config_mr[SHA512_DIGEST_SIZE];
u8 rtmr0[SHA256_DIGEST_SIZE];
u8 rtmr1[SHA384_DIGEST_SIZE];
u8 report_digest[SHA512_DIGEST_SIZE];
} sample_report = {
.static_mr = "static_mr",
.config_mr = "config_mr",
.rtmr0 = "rtmr0",
.rtmr1 = "rtmr1",
};
static int sample_report_refresh(const struct tsm_measurements *tm)
{
sha512((const u8 *)&sample_report,
offsetof(typeof(sample_report), report_digest),
sample_report.report_digest);
return 0;
}
static int sample_report_extend_mr(const struct tsm_measurements *tm,
const struct tsm_measurement_register *mr,
const u8 *data)
{
union {
struct sha256_ctx sha256;
struct sha384_ctx sha384;
struct sha512_ctx sha512;
} ctx;
switch (mr->mr_hash) {
case HASH_ALGO_SHA256:
sha256_init(&ctx.sha256);
sha256_update(&ctx.sha256, mr->mr_value, mr->mr_size);
sha256_update(&ctx.sha256, data, mr->mr_size);
sha256_final(&ctx.sha256, mr->mr_value);
return 0;
case HASH_ALGO_SHA384:
sha384_init(&ctx.sha384);
sha384_update(&ctx.sha384, mr->mr_value, mr->mr_size);
sha384_update(&ctx.sha384, data, mr->mr_size);
sha384_final(&ctx.sha384, mr->mr_value);
return 0;
case HASH_ALGO_SHA512:
sha512_init(&ctx.sha512);
sha512_update(&ctx.sha512, mr->mr_value, mr->mr_size);
sha512_update(&ctx.sha512, data, mr->mr_size);
sha512_final(&ctx.sha512, mr->mr_value);
return 0;
default:
pr_err("Unsupported hash algorithm: %d\n", mr->mr_hash);
return -EOPNOTSUPP;
}
}
#define MR_(mr, hash) .mr_value = &sample_report.mr, TSM_MR_(mr, hash)
static const struct tsm_measurement_register sample_mrs[] = {
/* static MR, read-only */
{ MR_(static_mr, SHA384) },
/* config MR, read-only */
{ MR_(config_mr, SHA512) | TSM_MR_F_NOHASH },
/* RTMR, direct extension prohibited */
{ MR_(rtmr0, SHA256) | TSM_MR_F_LIVE },
/* RTMR, direct extension allowed */
{ MR_(rtmr1, SHA384) | TSM_MR_F_RTMR },
/* RTMR, crypto agile, alaised to rtmr0 and rtmr1, respectively */
{ .mr_value = &sample_report.rtmr0,
TSM_MR_(rtmr_crypto_agile, SHA256) | TSM_MR_F_RTMR },
{ .mr_value = &sample_report.rtmr1,
TSM_MR_(rtmr_crypto_agile, SHA384) | TSM_MR_F_RTMR },
/* sha512 digest of the whole structure */
{ MR_(report_digest, SHA512) | TSM_MR_F_LIVE },
};
#undef MR_
static struct tsm_measurements sample_tm = {
.mrs = sample_mrs,
.nr_mrs = ARRAY_SIZE(sample_mrs),
.refresh = sample_report_refresh,
.write = sample_report_extend_mr,
};
static const struct attribute_group *sample_groups[] = {
NULL,
NULL,
};
static struct miscdevice sample_misc_dev = {
.name = KBUILD_MODNAME,
.minor = MISC_DYNAMIC_MINOR,
.groups = sample_groups,
};
static int __init tsm_mr_sample_init(void)
{
int rc;
sample_groups[0] = tsm_mr_create_attribute_group(&sample_tm);
if (IS_ERR(sample_groups[0]))
return PTR_ERR(sample_groups[0]);
rc = misc_register(&sample_misc_dev);
if (rc)
tsm_mr_free_attribute_group(sample_groups[0]);
return rc;
}
static void __exit tsm_mr_sample_exit(void)
{
misc_deregister(&sample_misc_dev);
tsm_mr_free_attribute_group(sample_groups[0]);
}
module_init(tsm_mr_sample_init);
module_exit(tsm_mr_sample_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Sample module using tsm-mr to expose emulated MRs");
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