[linux-2.6-block.git] / security / keys / trusted-keys / trusted_tpm2.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2004 IBM Corporation
 * Copyright (C) 2014 Intel Corporation
 */

#include <linux/asn1_encoder.h>
#include <linux/oid_registry.h>
#include <linux/string.h>
#include <linux/err.h>
#include <linux/tpm.h>
#include <linux/tpm_command.h>

#include <keys/trusted-type.h>
#include <keys/trusted_tpm.h>

#include <linux/unaligned.h>

#include "tpm2key.asn1.h"

static struct tpm2_hash tpm2_hash_map[] = {
	{HASH_ALGO_SHA1, TPM_ALG_SHA1},
	{HASH_ALGO_SHA256, TPM_ALG_SHA256},
	{HASH_ALGO_SHA384, TPM_ALG_SHA384},
	{HASH_ALGO_SHA512, TPM_ALG_SHA512},
	{HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
};

static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 };

static int tpm2_key_encode(struct trusted_key_payload *payload,
			   struct trusted_key_options *options,
			   u8 *src, u32 len)
{
	const int SCRATCH_SIZE = PAGE_SIZE;
	u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
	u8 *work = scratch, *work1;
	u8 *end_work = scratch + SCRATCH_SIZE;
	u8 *priv, *pub;
	u16 priv_len, pub_len;
	int ret;

	priv_len = get_unaligned_be16(src) + 2;
	priv = src;

	src += priv_len;

	pub_len = get_unaligned_be16(src) + 2;
	pub = src;

	if (!scratch)
		return -ENOMEM;

	work = asn1_encode_oid(work, end_work, tpm2key_oid,
			       asn1_oid_len(tpm2key_oid));

	if (options->blobauth_len == 0) {
		unsigned char bool[3], *w = bool;
		/* tag 0 is emptyAuth */
		w = asn1_encode_boolean(w, w + sizeof(bool), true);
		if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) {
			ret = PTR_ERR(w);
			goto err;
		}
		work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
	}

	/*
	 * Assume both octet strings will encode to a 2 byte definite length
	 *
	 * Note: For a well behaved TPM, this warning should never
	 * trigger, so if it does there's something nefarious going on
	 */
	if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
		 "BUG: scratch buffer is too small")) {
		ret = -EINVAL;
		goto err;
	}

	work = asn1_encode_integer(work, end_work, options->keyhandle);
	work = asn1_encode_octet_string(work, end_work, pub, pub_len);
	work = asn1_encode_octet_string(work, end_work, priv, priv_len);

	work1 = payload->blob;
	work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
				     scratch, work - scratch);
	if (IS_ERR(work1)) {
		ret = PTR_ERR(work1);
		pr_err("BUG: ASN.1 encoder failed with %d\n", ret);
		goto err;
	}

	kfree(scratch);
	return work1 - payload->blob;

err:
	kfree(scratch);
	return ret;
}

struct tpm2_key_context {
	u32 parent;
	const u8 *pub;
	u32 pub_len;
	const u8 *priv;
	u32 priv_len;
};

static int tpm2_key_decode(struct trusted_key_payload *payload,
			   struct trusted_key_options *options,
			   u8 **buf)
{
	int ret;
	struct tpm2_key_context ctx;
	u8 *blob;

	memset(&ctx, 0, sizeof(ctx));

	ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob,
			       payload->blob_len);
	if (ret < 0)
		return ret;

	if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE)
		return -EINVAL;

	blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL);
	if (!blob)
		return -ENOMEM;

	*buf = blob;
	options->keyhandle = ctx.parent;

	memcpy(blob, ctx.priv, ctx.priv_len);
	blob += ctx.priv_len;

	memcpy(blob, ctx.pub, ctx.pub_len);

	return 0;
}

int tpm2_key_parent(void *context, size_t hdrlen,
		  unsigned char tag,
		  const void *value, size_t vlen)
{
	struct tpm2_key_context *ctx = context;
	const u8 *v = value;
	int i;

	ctx->parent = 0;
	for (i = 0; i < vlen; i++) {
		ctx->parent <<= 8;
		ctx->parent |= v[i];
	}

	return 0;
}

int tpm2_key_type(void *context, size_t hdrlen,
		unsigned char tag,
		const void *value, size_t vlen)
{
	enum OID oid = look_up_OID(value, vlen);

	if (oid != OID_TPMSealedData) {
		char buffer[50];

		sprint_oid(value, vlen, buffer, sizeof(buffer));
		pr_debug("OID is \"%s\" which is not TPMSealedData\n",
			 buffer);
		return -EINVAL;
	}

	return 0;
}

int tpm2_key_pub(void *context, size_t hdrlen,
	       unsigned char tag,
	       const void *value, size_t vlen)
{
	struct tpm2_key_context *ctx = context;

	ctx->pub = value;
	ctx->pub_len = vlen;

	return 0;
}

int tpm2_key_priv(void *context, size_t hdrlen,
		unsigned char tag,
		const void *value, size_t vlen)
{
	struct tpm2_key_context *ctx = context;

	ctx->priv = value;
	ctx->priv_len = vlen;

	return 0;
}

/**
 * tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
 *
 * @buf: an allocated tpm_buf instance
 * @session_handle: session handle
 * @nonce: the session nonce, may be NULL if not used
 * @nonce_len: the session nonce length, may be 0 if not used
 * @attributes: the session attributes
 * @hmac: the session HMAC or password, may be NULL if not used
 * @hmac_len: the session HMAC or password length, maybe 0 if not used
 */
static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
				 const u8 *nonce, u16 nonce_len,
				 u8 attributes,
				 const u8 *hmac, u16 hmac_len)
{
	tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
	tpm_buf_append_u32(buf, session_handle);
	tpm_buf_append_u16(buf, nonce_len);

	if (nonce && nonce_len)
		tpm_buf_append(buf, nonce, nonce_len);

	tpm_buf_append_u8(buf, attributes);
	tpm_buf_append_u16(buf, hmac_len);

	if (hmac && hmac_len)
		tpm_buf_append(buf, hmac, hmac_len);
}

/**
 * tpm2_seal_trusted() - seal the payload of a trusted key
 *
 * @chip: TPM chip to use
 * @payload: the key data in clear and encrypted form
 * @options: authentication values and other options
 *
 * Return: < 0 on error and 0 on success.
 */
int tpm2_seal_trusted(struct tpm_chip *chip,
		      struct trusted_key_payload *payload,
		      struct trusted_key_options *options)
{
	off_t offset = TPM_HEADER_SIZE;
	struct tpm_buf buf, sized;
	int blob_len = 0;
	u32 hash;
	u32 flags;
	int i;
	int rc;

	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
		if (options->hash == tpm2_hash_map[i].crypto_id) {
			hash = tpm2_hash_map[i].tpm_id;
			break;
		}
	}

	if (i == ARRAY_SIZE(tpm2_hash_map))
		return -EINVAL;

	if (!options->keyhandle)
		return -EINVAL;

	rc = tpm_try_get_ops(chip);
	if (rc)
		return rc;

	rc = tpm2_start_auth_session(chip);
	if (rc)
		goto out_put;

	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
	if (rc) {
		tpm2_end_auth_session(chip);
		goto out_put;
	}

	rc = tpm_buf_init_sized(&sized);
	if (rc) {
		tpm_buf_destroy(&buf);
		tpm2_end_auth_session(chip);
		goto out_put;
	}

	tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
	tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT,
				    options->keyauth, TPM_DIGEST_SIZE);

	/* sensitive */
	tpm_buf_append_u16(&sized, options->blobauth_len);

	if (options->blobauth_len)
		tpm_buf_append(&sized, options->blobauth, options->blobauth_len);

	tpm_buf_append_u16(&sized, payload->key_len);
	tpm_buf_append(&sized, payload->key, payload->key_len);
	tpm_buf_append(&buf, sized.data, sized.length);

	/* public */
	tpm_buf_reset_sized(&sized);
	tpm_buf_append_u16(&sized, TPM_ALG_KEYEDHASH);
	tpm_buf_append_u16(&sized, hash);

	/* key properties */
	flags = 0;
	flags |= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH;
	flags |= payload->migratable ? 0 : (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT);
	tpm_buf_append_u32(&sized, flags);

	/* policy */
	tpm_buf_append_u16(&sized, options->policydigest_len);
	if (options->policydigest_len)
		tpm_buf_append(&sized, options->policydigest, options->policydigest_len);

	/* public parameters */
	tpm_buf_append_u16(&sized, TPM_ALG_NULL);
	tpm_buf_append_u16(&sized, 0);

	tpm_buf_append(&buf, sized.data, sized.length);

	/* outside info */
	tpm_buf_append_u16(&buf, 0);

	/* creation PCR */
	tpm_buf_append_u32(&buf, 0);

	if (buf.flags & TPM_BUF_OVERFLOW) {
		rc = -E2BIG;
		tpm2_end_auth_session(chip);
		goto out;
	}

	tpm_buf_fill_hmac_session(chip, &buf);
	rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
	if (rc)
		goto out;

	blob_len = tpm_buf_read_u32(&buf, &offset);
	if (blob_len > MAX_BLOB_SIZE || buf.flags & TPM_BUF_BOUNDARY_ERROR) {
		rc = -E2BIG;
		goto out;
	}
	if (buf.length - offset < blob_len) {
		rc = -EFAULT;
		goto out;
	}

	blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);

out:
	tpm_buf_destroy(&sized);
	tpm_buf_destroy(&buf);

	if (rc > 0) {
		if (tpm2_rc_value(rc) == TPM2_RC_HASH)
			rc = -EINVAL;
		else
			rc = -EPERM;
	}
	if (blob_len < 0)
		rc = blob_len;
	else
		payload->blob_len = blob_len;

out_put:
	tpm_put_ops(chip);
	return rc;
}

/**
 * tpm2_load_cmd() - execute a TPM2_Load command
 *
 * @chip: TPM chip to use
 * @payload: the key data in clear and encrypted form
 * @options: authentication values and other options
 * @blob_handle: returned blob handle
 *
 * Return: 0 on success.
 *        -E2BIG on wrong payload size.
 *        -EPERM on tpm error status.
 *        < 0 error from tpm_send.
 */
static int tpm2_load_cmd(struct tpm_chip *chip,
			 struct trusted_key_payload *payload,
			 struct trusted_key_options *options,
			 u32 *blob_handle)
{
	struct tpm_buf buf;
	unsigned int private_len;
	unsigned int public_len;
	unsigned int blob_len;
	u8 *blob, *pub;
	int rc;
	u32 attrs;

	rc = tpm2_key_decode(payload, options, &blob);
	if (rc) {
		/* old form */
		blob = payload->blob;
		payload->old_format = 1;
	}

	/* new format carries keyhandle but old format doesn't */
	if (!options->keyhandle)
		return -EINVAL;

	/* must be big enough for at least the two be16 size counts */
	if (payload->blob_len < 4)
		return -EINVAL;

	private_len = get_unaligned_be16(blob);

	/* must be big enough for following public_len */
	if (private_len + 2 + 2 > (payload->blob_len))
		return -E2BIG;

	public_len = get_unaligned_be16(blob + 2 + private_len);
	if (private_len + 2 + public_len + 2 > payload->blob_len)
		return -E2BIG;

	pub = blob + 2 + private_len + 2;
	/* key attributes are always at offset 4 */
	attrs = get_unaligned_be32(pub + 4);

	if ((attrs & (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT)) ==
	    (TPM2_OA_FIXED_TPM | TPM2_OA_FIXED_PARENT))
		payload->migratable = 0;
	else
		payload->migratable = 1;

	blob_len = private_len + public_len + 4;
	if (blob_len > payload->blob_len)
		return -E2BIG;

	rc = tpm2_start_auth_session(chip);
	if (rc)
		return rc;

	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
	if (rc) {
		tpm2_end_auth_session(chip);
		return rc;
	}

	tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
	tpm_buf_append_hmac_session(chip, &buf, 0, options->keyauth,
				    TPM_DIGEST_SIZE);

	tpm_buf_append(&buf, blob, blob_len);

	if (buf.flags & TPM_BUF_OVERFLOW) {
		rc = -E2BIG;
		tpm2_end_auth_session(chip);
		goto out;
	}

	tpm_buf_fill_hmac_session(chip, &buf);
	rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
	if (!rc)
		*blob_handle = be32_to_cpup(
			(__be32 *) &buf.data[TPM_HEADER_SIZE]);

out:
	if (blob != payload->blob)
		kfree(blob);
	tpm_buf_destroy(&buf);

	if (rc > 0)
		rc = -EPERM;

	return rc;
}

/**
 * tpm2_unseal_cmd() - execute a TPM2_Unload command
 *
 * @chip: TPM chip to use
 * @payload: the key data in clear and encrypted form
 * @options: authentication values and other options
 * @blob_handle: blob handle
 *
 * Return: 0 on success
 *         -EPERM on tpm error status
 *         < 0 error from tpm_send
 */
static int tpm2_unseal_cmd(struct tpm_chip *chip,
			   struct trusted_key_payload *payload,
			   struct trusted_key_options *options,
			   u32 blob_handle)
{
	struct tpm_buf buf;
	u16 data_len;
	u8 *data;
	int rc;

	rc = tpm2_start_auth_session(chip);
	if (rc)
		return rc;

	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
	if (rc) {
		tpm2_end_auth_session(chip);
		return rc;
	}

	tpm_buf_append_name(chip, &buf, blob_handle, NULL);

	if (!options->policyhandle) {
		tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT,
					    options->blobauth,
					    options->blobauth_len);
	} else {
		/*
		 * FIXME: The policy session was generated outside the
		 * kernel so we don't known the nonce and thus can't
		 * calculate a HMAC on it.  Therefore, the user can
		 * only really use TPM2_PolicyPassword and we must
		 * send down the plain text password, which could be
		 * intercepted.  We can still encrypt the returned
		 * key, but that's small comfort since the interposer
		 * could repeat our actions with the exfiltrated
		 * password.
		 */
		tpm2_buf_append_auth(&buf, options->policyhandle,
				     NULL /* nonce */, 0, 0,
				     options->blobauth, options->blobauth_len);
		tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT,
						NULL, 0);
	}

	tpm_buf_fill_hmac_session(chip, &buf);
	rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
	if (rc > 0)
		rc = -EPERM;

	if (!rc) {
		data_len = be16_to_cpup(
			(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
		if (data_len < MIN_KEY_SIZE ||  data_len > MAX_KEY_SIZE) {
			rc = -EFAULT;
			goto out;
		}

		if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
			rc = -EFAULT;
			goto out;
		}
		data = &buf.data[TPM_HEADER_SIZE + 6];

		if (payload->old_format) {
			/* migratable flag is at the end of the key */
			memcpy(payload->key, data, data_len - 1);
			payload->key_len = data_len - 1;
			payload->migratable = data[data_len - 1];
		} else {
			/*
			 * migratable flag already collected from key
			 * attributes
			 */
			memcpy(payload->key, data, data_len);
			payload->key_len = data_len;
		}
	}

out:
	tpm_buf_destroy(&buf);
	return rc;
}

/**
 * tpm2_unseal_trusted() - unseal the payload of a trusted key
 *
 * @chip: TPM chip to use
 * @payload: the key data in clear and encrypted form
 * @options: authentication values and other options
 *
 * Return: Same as with tpm_send.
 */
int tpm2_unseal_trusted(struct tpm_chip *chip,
			struct trusted_key_payload *payload,
			struct trusted_key_options *options)
{
	u32 blob_handle;
	int rc;

	rc = tpm_try_get_ops(chip);
	if (rc)
		return rc;

	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
	if (rc)
		goto out;

	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
	tpm2_flush_context(chip, blob_handle);

out:
	tpm_put_ops(chip);

	return rc;
}
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/*
	3	* Copyright (C) 2004 IBM Corporation
	4	* Copyright (C) 2014 Intel Corporation
	5	*/
	6
	7	#include <linux/asn1_encoder.h>
	8	#include <linux/oid_registry.h>
	9	#include <linux/string.h>
	10	#include <linux/err.h>
	11	#include <linux/tpm.h>
	12	#include <linux/tpm_command.h>
	13
	14	#include <keys/trusted-type.h>
	15	#include <keys/trusted_tpm.h>
	16
	17	#include <linux/unaligned.h>
	18
	19	#include "tpm2key.asn1.h"
	20
	21	static struct tpm2_hash tpm2_hash_map[] = {
	22	{HASH_ALGO_SHA1, TPM_ALG_SHA1},
	23	{HASH_ALGO_SHA256, TPM_ALG_SHA256},
	24	{HASH_ALGO_SHA384, TPM_ALG_SHA384},
	25	{HASH_ALGO_SHA512, TPM_ALG_SHA512},
	26	{HASH_ALGO_SM3_256, TPM_ALG_SM3_256},
	27	};
	28
	29	static u32 tpm2key_oid[] = { 2, 23, 133, 10, 1, 5 };
	30
	31	static int tpm2_key_encode(struct trusted_key_payload *payload,
	32	struct trusted_key_options *options,
	33	u8 *src, u32 len)
	34	{
	35	const int SCRATCH_SIZE = PAGE_SIZE;
	36	u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL);
	37	u8 work = scratch, work1;
	38	u8 *end_work = scratch + SCRATCH_SIZE;
	39	u8 priv, pub;
	40	u16 priv_len, pub_len;
	41	int ret;
	42
	43	priv_len = get_unaligned_be16(src) + 2;
	44	priv = src;
	45
	46	src += priv_len;
	47
	48	pub_len = get_unaligned_be16(src) + 2;
	49	pub = src;
	50
	51	if (!scratch)
	52	return -ENOMEM;
	53
	54	work = asn1_encode_oid(work, end_work, tpm2key_oid,
	55	asn1_oid_len(tpm2key_oid));
	56
	57	if (options->blobauth_len == 0) {
	58	unsigned char bool[3], *w = bool;
	59	/* tag 0 is emptyAuth */
	60	w = asn1_encode_boolean(w, w + sizeof(bool), true);
	61	if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) {
	62	ret = PTR_ERR(w);
	63	goto err;
	64	}
	65	work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
	66	}
	67
	68	/*
	69	* Assume both octet strings will encode to a 2 byte definite length
	70	*
	71	* Note: For a well behaved TPM, this warning should never
	72	* trigger, so if it does there's something nefarious going on
	73	*/
	74	if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
	75	"BUG: scratch buffer is too small")) {
	76	ret = -EINVAL;
	77	goto err;
	78	}
	79
	80	work = asn1_encode_integer(work, end_work, options->keyhandle);
	81	work = asn1_encode_octet_string(work, end_work, pub, pub_len);
	82	work = asn1_encode_octet_string(work, end_work, priv, priv_len);
	83
	84	work1 = payload->blob;
	85	work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
	86	scratch, work - scratch);
	87	if (IS_ERR(work1)) {
	88	ret = PTR_ERR(work1);
	89	pr_err("BUG: ASN.1 encoder failed with %d\n", ret);
	90	goto err;
	91	}
	92
	93	kfree(scratch);
	94	return work1 - payload->blob;
	95
	96	err:
	97	kfree(scratch);
	98	return ret;
	99	}
	100
	101	struct tpm2_key_context {
	102	u32 parent;
	103	const u8 *pub;
	104	u32 pub_len;
	105	const u8 *priv;
	106	u32 priv_len;
	107	};
	108
	109	static int tpm2_key_decode(struct trusted_key_payload *payload,
	110	struct trusted_key_options *options,
	111	u8 **buf)
	112	{
	113	int ret;
	114	struct tpm2_key_context ctx;
	115	u8 *blob;
	116
	117	memset(&ctx, 0, sizeof(ctx));
	118
	119	ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob,
	120	payload->blob_len);
	121	if (ret < 0)
	122	return ret;
	123
	124	if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE)
	125	return -EINVAL;
	126
	127	blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL);
	128	if (!blob)
	129	return -ENOMEM;
	130
	131	*buf = blob;
	132	options->keyhandle = ctx.parent;
	133
	134	memcpy(blob, ctx.priv, ctx.priv_len);
	135	blob += ctx.priv_len;
	136
	137	memcpy(blob, ctx.pub, ctx.pub_len);
	138
	139	return 0;
	140	}
	141
	142	int tpm2_key_parent(void *context, size_t hdrlen,
	143	unsigned char tag,
	144	const void *value, size_t vlen)
	145	{
	146	struct tpm2_key_context *ctx = context;
	147	const u8 *v = value;
	148	int i;
	149
	150	ctx->parent = 0;
	151	for (i = 0; i < vlen; i++) {
	152	ctx->parent <<= 8;
	153	ctx->parent \|= v[i];
	154	}
	155
	156	return 0;
	157	}
	158
	159	int tpm2_key_type(void *context, size_t hdrlen,
	160	unsigned char tag,
	161	const void *value, size_t vlen)
	162	{
	163	enum OID oid = look_up_OID(value, vlen);
	164
	165	if (oid != OID_TPMSealedData) {
	166	char buffer[50];
	167
	168	sprint_oid(value, vlen, buffer, sizeof(buffer));
	169	pr_debug("OID is \"%s\" which is not TPMSealedData\n",
	170	buffer);
	171	return -EINVAL;
	172	}
	173
	174	return 0;
	175	}
	176
	177	int tpm2_key_pub(void *context, size_t hdrlen,
	178	unsigned char tag,
	179	const void *value, size_t vlen)
	180	{
	181	struct tpm2_key_context *ctx = context;
	182
	183	ctx->pub = value;
	184	ctx->pub_len = vlen;
	185
	186	return 0;
	187	}
	188
	189	int tpm2_key_priv(void *context, size_t hdrlen,
	190	unsigned char tag,
	191	const void *value, size_t vlen)
	192	{
	193	struct tpm2_key_context *ctx = context;
	194
	195	ctx->priv = value;
	196	ctx->priv_len = vlen;
	197
	198	return 0;
	199	}
	200
	201	/**
	202	* tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
	203	*
	204	* @buf: an allocated tpm_buf instance
	205	* @session_handle: session handle
	206	* @nonce: the session nonce, may be NULL if not used
	207	* @nonce_len: the session nonce length, may be 0 if not used
	208	* @attributes: the session attributes
	209	* @hmac: the session HMAC or password, may be NULL if not used
	210	* @hmac_len: the session HMAC or password length, maybe 0 if not used
	211	*/
	212	static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
	213	const u8 *nonce, u16 nonce_len,
	214	u8 attributes,
	215	const u8 *hmac, u16 hmac_len)
	216	{
	217	tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
	218	tpm_buf_append_u32(buf, session_handle);
	219	tpm_buf_append_u16(buf, nonce_len);
	220
	221	if (nonce && nonce_len)
	222	tpm_buf_append(buf, nonce, nonce_len);
	223
	224	tpm_buf_append_u8(buf, attributes);
	225	tpm_buf_append_u16(buf, hmac_len);
	226
	227	if (hmac && hmac_len)
	228	tpm_buf_append(buf, hmac, hmac_len);
	229	}
	230
	231	/**
	232	* tpm2_seal_trusted() - seal the payload of a trusted key
	233	*
	234	* @chip: TPM chip to use
	235	* @payload: the key data in clear and encrypted form
	236	* @options: authentication values and other options
	237	*
	238	* Return: < 0 on error and 0 on success.
	239	*/
	240	int tpm2_seal_trusted(struct tpm_chip *chip,
	241	struct trusted_key_payload *payload,
	242	struct trusted_key_options *options)
	243	{
	244	off_t offset = TPM_HEADER_SIZE;
	245	struct tpm_buf buf, sized;
	246	int blob_len = 0;
	247	u32 hash;
	248	u32 flags;
	249	int i;
	250	int rc;
	251
	252	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
	253	if (options->hash == tpm2_hash_map[i].crypto_id) {
	254	hash = tpm2_hash_map[i].tpm_id;
	255	break;
	256	}
	257	}
	258
	259	if (i == ARRAY_SIZE(tpm2_hash_map))
	260	return -EINVAL;
	261
	262	if (!options->keyhandle)
	263	return -EINVAL;
	264
	265	rc = tpm_try_get_ops(chip);
	266	if (rc)
	267	return rc;
	268
	269	rc = tpm2_start_auth_session(chip);
	270	if (rc)
	271	goto out_put;
	272
	273	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
	274	if (rc) {
	275	tpm2_end_auth_session(chip);
	276	goto out_put;
	277	}
	278
	279	rc = tpm_buf_init_sized(&sized);
	280	if (rc) {
	281	tpm_buf_destroy(&buf);
	282	tpm2_end_auth_session(chip);
	283	goto out_put;
	284	}
	285
	286	tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
	287	tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT,
	288	options->keyauth, TPM_DIGEST_SIZE);
	289
	290	/* sensitive */
	291	tpm_buf_append_u16(&sized, options->blobauth_len);
	292
	293	if (options->blobauth_len)
	294	tpm_buf_append(&sized, options->blobauth, options->blobauth_len);
	295
	296	tpm_buf_append_u16(&sized, payload->key_len);
	297	tpm_buf_append(&sized, payload->key, payload->key_len);
	298	tpm_buf_append(&buf, sized.data, sized.length);
	299
	300	/* public */
	301	tpm_buf_reset_sized(&sized);
	302	tpm_buf_append_u16(&sized, TPM_ALG_KEYEDHASH);
	303	tpm_buf_append_u16(&sized, hash);
	304
	305	/* key properties */
	306	flags = 0;
	307	flags \|= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH;
	308	flags \|= payload->migratable ? 0 : (TPM2_OA_FIXED_TPM \| TPM2_OA_FIXED_PARENT);
	309	tpm_buf_append_u32(&sized, flags);
	310
	311	/* policy */
	312	tpm_buf_append_u16(&sized, options->policydigest_len);
	313	if (options->policydigest_len)
	314	tpm_buf_append(&sized, options->policydigest, options->policydigest_len);
	315
	316	/* public parameters */
	317	tpm_buf_append_u16(&sized, TPM_ALG_NULL);
	318	tpm_buf_append_u16(&sized, 0);
	319
	320	tpm_buf_append(&buf, sized.data, sized.length);
	321
	322	/* outside info */
	323	tpm_buf_append_u16(&buf, 0);
	324
	325	/* creation PCR */
	326	tpm_buf_append_u32(&buf, 0);
	327
	328	if (buf.flags & TPM_BUF_OVERFLOW) {
	329	rc = -E2BIG;
	330	tpm2_end_auth_session(chip);
	331	goto out;
	332	}
	333
	334	tpm_buf_fill_hmac_session(chip, &buf);
	335	rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
	336	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
	337	if (rc)
	338	goto out;
	339
	340	blob_len = tpm_buf_read_u32(&buf, &offset);
	341	if (blob_len > MAX_BLOB_SIZE \|\| buf.flags & TPM_BUF_BOUNDARY_ERROR) {
	342	rc = -E2BIG;
	343	goto out;
	344	}
	345	if (buf.length - offset < blob_len) {
	346	rc = -EFAULT;
	347	goto out;
	348	}
	349
	350	blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
	351
	352	out:
	353	tpm_buf_destroy(&sized);
	354	tpm_buf_destroy(&buf);
	355
	356	if (rc > 0) {
	357	if (tpm2_rc_value(rc) == TPM2_RC_HASH)
	358	rc = -EINVAL;
	359	else
	360	rc = -EPERM;
	361	}
	362	if (blob_len < 0)
	363	rc = blob_len;
	364	else
	365	payload->blob_len = blob_len;
	366
	367	out_put:
	368	tpm_put_ops(chip);
	369	return rc;
	370	}
	371
	372	/**
	373	* tpm2_load_cmd() - execute a TPM2_Load command
	374	*
	375	* @chip: TPM chip to use
	376	* @payload: the key data in clear and encrypted form
	377	* @options: authentication values and other options
	378	* @blob_handle: returned blob handle
	379	*
	380	* Return: 0 on success.
	381	* -E2BIG on wrong payload size.
	382	* -EPERM on tpm error status.
	383	* < 0 error from tpm_send.
	384	*/
	385	static int tpm2_load_cmd(struct tpm_chip *chip,
	386	struct trusted_key_payload *payload,
	387	struct trusted_key_options *options,
	388	u32 *blob_handle)
	389	{
	390	struct tpm_buf buf;
	391	unsigned int private_len;
	392	unsigned int public_len;
	393	unsigned int blob_len;
	394	u8 blob, pub;
	395	int rc;
	396	u32 attrs;
	397
	398	rc = tpm2_key_decode(payload, options, &blob);
	399	if (rc) {
	400	/* old form */
	401	blob = payload->blob;
	402	payload->old_format = 1;
	403	}
	404
	405	/* new format carries keyhandle but old format doesn't */
	406	if (!options->keyhandle)
	407	return -EINVAL;
	408
	409	/* must be big enough for at least the two be16 size counts */
	410	if (payload->blob_len < 4)
	411	return -EINVAL;
	412
	413	private_len = get_unaligned_be16(blob);
	414
	415	/* must be big enough for following public_len */
	416	if (private_len + 2 + 2 > (payload->blob_len))
	417	return -E2BIG;
	418
	419	public_len = get_unaligned_be16(blob + 2 + private_len);
	420	if (private_len + 2 + public_len + 2 > payload->blob_len)
	421	return -E2BIG;
	422
	423	pub = blob + 2 + private_len + 2;
	424	/* key attributes are always at offset 4 */
	425	attrs = get_unaligned_be32(pub + 4);
	426
	427	if ((attrs & (TPM2_OA_FIXED_TPM \| TPM2_OA_FIXED_PARENT)) ==
	428	(TPM2_OA_FIXED_TPM \| TPM2_OA_FIXED_PARENT))
	429	payload->migratable = 0;
	430	else
	431	payload->migratable = 1;
	432
	433	blob_len = private_len + public_len + 4;
	434	if (blob_len > payload->blob_len)
	435	return -E2BIG;
	436
	437	rc = tpm2_start_auth_session(chip);
	438	if (rc)
	439	return rc;
	440
	441	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
	442	if (rc) {
	443	tpm2_end_auth_session(chip);
	444	return rc;
	445	}
	446
	447	tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
	448	tpm_buf_append_hmac_session(chip, &buf, 0, options->keyauth,
	449	TPM_DIGEST_SIZE);
	450
	451	tpm_buf_append(&buf, blob, blob_len);
	452
	453	if (buf.flags & TPM_BUF_OVERFLOW) {
	454	rc = -E2BIG;
	455	tpm2_end_auth_session(chip);
	456	goto out;
	457	}
	458
	459	tpm_buf_fill_hmac_session(chip, &buf);
	460	rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
	461	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
	462	if (!rc)
	463	*blob_handle = be32_to_cpup(
	464	(__be32 *) &buf.data[TPM_HEADER_SIZE]);
	465
	466	out:
	467	if (blob != payload->blob)
	468	kfree(blob);
	469	tpm_buf_destroy(&buf);
	470
	471	if (rc > 0)
	472	rc = -EPERM;
	473
	474	return rc;
	475	}
	476
	477	/**
	478	* tpm2_unseal_cmd() - execute a TPM2_Unload command
	479	*
	480	* @chip: TPM chip to use
	481	* @payload: the key data in clear and encrypted form
	482	* @options: authentication values and other options
	483	* @blob_handle: blob handle
	484	*
	485	* Return: 0 on success
	486	* -EPERM on tpm error status
	487	* < 0 error from tpm_send
	488	*/
	489	static int tpm2_unseal_cmd(struct tpm_chip *chip,
	490	struct trusted_key_payload *payload,
	491	struct trusted_key_options *options,
	492	u32 blob_handle)
	493	{
	494	struct tpm_buf buf;
	495	u16 data_len;
	496	u8 *data;
	497	int rc;
	498
	499	rc = tpm2_start_auth_session(chip);
	500	if (rc)
	501	return rc;
	502
	503	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
	504	if (rc) {
	505	tpm2_end_auth_session(chip);
	506	return rc;
	507	}
	508
	509	tpm_buf_append_name(chip, &buf, blob_handle, NULL);
	510
	511	if (!options->policyhandle) {
	512	tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT,
	513	options->blobauth,
	514	options->blobauth_len);
	515	} else {
	516	/*
	517	* FIXME: The policy session was generated outside the
	518	* kernel so we don't known the nonce and thus can't
	519	* calculate a HMAC on it. Therefore, the user can
	520	* only really use TPM2_PolicyPassword and we must
	521	* send down the plain text password, which could be
	522	* intercepted. We can still encrypt the returned
	523	* key, but that's small comfort since the interposer
	524	* could repeat our actions with the exfiltrated
	525	* password.
	526	*/
	527	tpm2_buf_append_auth(&buf, options->policyhandle,
	528	NULL /* nonce */, 0, 0,
	529	options->blobauth, options->blobauth_len);
	530	tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT,
	531	NULL, 0);
	532	}
	533
	534	tpm_buf_fill_hmac_session(chip, &buf);
	535	rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
	536	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
	537	if (rc > 0)
	538	rc = -EPERM;
	539
	540	if (!rc) {
	541	data_len = be16_to_cpup(
	542	(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
	543	if (data_len < MIN_KEY_SIZE \|\| data_len > MAX_KEY_SIZE) {
	544	rc = -EFAULT;
	545	goto out;
	546	}
	547
	548	if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
	549	rc = -EFAULT;
	550	goto out;
	551	}
	552	data = &buf.data[TPM_HEADER_SIZE + 6];
	553
	554	if (payload->old_format) {
	555	/* migratable flag is at the end of the key */
	556	memcpy(payload->key, data, data_len - 1);
	557	payload->key_len = data_len - 1;
	558	payload->migratable = data[data_len - 1];
	559	} else {
	560	/*
	561	* migratable flag already collected from key
	562	* attributes
	563	*/
	564	memcpy(payload->key, data, data_len);
	565	payload->key_len = data_len;
	566	}
	567	}
	568
	569	out:
	570	tpm_buf_destroy(&buf);
	571	return rc;
	572	}
	573
	574	/**
	575	* tpm2_unseal_trusted() - unseal the payload of a trusted key
	576	*
	577	* @chip: TPM chip to use
	578	* @payload: the key data in clear and encrypted form
	579	* @options: authentication values and other options
	580	*
	581	* Return: Same as with tpm_send.
	582	*/
	583	int tpm2_unseal_trusted(struct tpm_chip *chip,
	584	struct trusted_key_payload *payload,
	585	struct trusted_key_options *options)
	586	{
	587	u32 blob_handle;
	588	int rc;
	589
	590	rc = tpm_try_get_ops(chip);
	591	if (rc)
	592	return rc;
	593
	594	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
	595	if (rc)
	596	goto out;
	597
	598	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
	599	tpm2_flush_context(chip, blob_handle);
	600
	601	out:
	602	tpm_put_ops(chip);
	603
	604	return rc;
	605	}