[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 <asm/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;

	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"))
			return PTR_ERR(w);
		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"))
		return -EINVAL;

	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 (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed"))
		return PTR_ERR(work1);

	return work1 - payload->blob;
}

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
2e19e101 SG	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/*
	3	* Copyright (C) 2004 IBM Corporation
	4	* Copyright (C) 2014 Intel Corporation
	5	*/
	6
f2219745 JB	7	#include <linux/asn1_encoder.h>
f2219745 JB	8	#include <linux/oid_registry.h>
2e19e101 SG	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
f2219745 JB	17	#include <asm/unaligned.h>
	18
	19	#include "tpm2key.asn1.h"
	20
2e19e101 SG	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
f2219745 JB	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
	42	priv_len = get_unaligned_be16(src) + 2;
	43	priv = src;
	44
	45	src += priv_len;
	46
	47	pub_len = get_unaligned_be16(src) + 2;
	48	pub = src;
	49
	50	if (!scratch)
	51	return -ENOMEM;
	52
	53	work = asn1_encode_oid(work, end_work, tpm2key_oid,
	54	asn1_oid_len(tpm2key_oid));
	55
	56	if (options->blobauth_len == 0) {
	57	unsigned char bool[3], *w = bool;
	58	/* tag 0 is emptyAuth */
	59	w = asn1_encode_boolean(w, w + sizeof(bool), true);
	60	if (WARN(IS_ERR(w), "BUG: Boolean failed to encode"))
	61	return PTR_ERR(w);
	62	work = asn1_encode_tag(work, end_work, 0, bool, w - bool);
	63	}
	64
	65	/*
	66	* Assume both octet strings will encode to a 2 byte definite length
	67	*
	68	* Note: For a well behaved TPM, this warning should never
	69	* trigger, so if it does there's something nefarious going on
	70	*/
	71	if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE,
	72	"BUG: scratch buffer is too small"))
	73	return -EINVAL;
	74
	75	work = asn1_encode_integer(work, end_work, options->keyhandle);
	76	work = asn1_encode_octet_string(work, end_work, pub, pub_len);
	77	work = asn1_encode_octet_string(work, end_work, priv, priv_len);
	78
	79	work1 = payload->blob;
	80	work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob),
	81	scratch, work - scratch);
	82	if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed"))
	83	return PTR_ERR(work1);
	84
	85	return work1 - payload->blob;
	86	}
	87
	88	struct tpm2_key_context {
	89	u32 parent;
	90	const u8 *pub;
	91	u32 pub_len;
	92	const u8 *priv;
93	u32 priv_len;
94	};
95
96	static int tpm2_key_decode(struct trusted_key_payload *payload,
97	struct trusted_key_options *options,
98	u8 **buf)
99	{
100	int ret;
101	struct tpm2_key_context ctx;
102	u8 *blob;
103
104	memset(&ctx, 0, sizeof(ctx));
105
106	ret = asn1_ber_decoder(&tpm2key_decoder, &ctx, payload->blob,
107	payload->blob_len);
108	if (ret < 0)
109	return ret;
110
111	if (ctx.priv_len + ctx.pub_len > MAX_BLOB_SIZE)
112	return -EINVAL;
113
114	blob = kmalloc(ctx.priv_len + ctx.pub_len + 4, GFP_KERNEL);
115	if (!blob)
116	return -ENOMEM;
117
118	*buf = blob;
119	options->keyhandle = ctx.parent;
120
121	memcpy(blob, ctx.priv, ctx.priv_len);
122	blob += ctx.priv_len;
123
124	memcpy(blob, ctx.pub, ctx.pub_len);
125
126	return 0;
127	}
128
129	int tpm2_key_parent(void *context, size_t hdrlen,
130	unsigned char tag,
131	const void *value, size_t vlen)
132	{
133	struct tpm2_key_context *ctx = context;
134	const u8 *v = value;
135	int i;
136
137	ctx->parent = 0;
138	for (i = 0; i < vlen; i++) {
139	ctx->parent <<= 8;
140	ctx->parent \|= v[i];
141	}
142
143	return 0;
144	}
145
146	int tpm2_key_type(void *context, size_t hdrlen,
147	unsigned char tag,
148	const void *value, size_t vlen)
149	{
150	enum OID oid = look_up_OID(value, vlen);
151
152	if (oid != OID_TPMSealedData) {
153	char buffer[50];
154
155	sprint_oid(value, vlen, buffer, sizeof(buffer));
156	pr_debug("OID is \"%s\" which is not TPMSealedData\n",
157	buffer);
158	return -EINVAL;
159	}
160
161	return 0;
162	}
163
164	int tpm2_key_pub(void *context, size_t hdrlen,
165	unsigned char tag,
166	const void *value, size_t vlen)
167	{
168	struct tpm2_key_context *ctx = context;
169
170	ctx->pub = value;
171	ctx->pub_len = vlen;
172
173	return 0;
174	}
175
176	int tpm2_key_priv(void *context, size_t hdrlen,
177	unsigned char tag,
178	const void *value, size_t vlen)
179	{
180	struct tpm2_key_context *ctx = context;
181
182	ctx->priv = value;
183	ctx->priv_len = vlen;
184
185	return 0;
186	}
187
2e19e101	188	/**
2a415274	189	* tpm2_buf_append_auth() - append TPMS_AUTH_COMMAND to the buffer.
2e19e101 SG	190	*
	191	* @buf: an allocated tpm_buf instance
	192	* @session_handle: session handle
	193	* @nonce: the session nonce, may be NULL if not used
	194	* @nonce_len: the session nonce length, may be 0 if not used
	195	* @attributes: the session attributes
	196	* @hmac: the session HMAC or password, may be NULL if not used
	197	* @hmac_len: the session HMAC or password length, maybe 0 if not used
	198	*/
	199	static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle,
	200	const u8 *nonce, u16 nonce_len,
	201	u8 attributes,
	202	const u8 *hmac, u16 hmac_len)
	203	{
	204	tpm_buf_append_u32(buf, 9 + nonce_len + hmac_len);
	205	tpm_buf_append_u32(buf, session_handle);
	206	tpm_buf_append_u16(buf, nonce_len);
	207
	208	if (nonce && nonce_len)
	209	tpm_buf_append(buf, nonce, nonce_len);
	210
	211	tpm_buf_append_u8(buf, attributes);
	212	tpm_buf_append_u16(buf, hmac_len);
	213
	214	if (hmac && hmac_len)
	215	tpm_buf_append(buf, hmac, hmac_len);
	216	}
	217
	218	/**
	219	* tpm2_seal_trusted() - seal the payload of a trusted key
	220	*
	221	* @chip: TPM chip to use
	222	* @payload: the key data in clear and encrypted form
	223	* @options: authentication values and other options
	224	*
	225	* Return: < 0 on error and 0 on success.
	226	*/
	227	int tpm2_seal_trusted(struct tpm_chip *chip,
	228	struct trusted_key_payload *payload,
	229	struct trusted_key_options *options)
	230	{
40813f18 JS	231	off_t offset = TPM_HEADER_SIZE;
40813f18 JS	232	struct tpm_buf buf, sized;
f2219745	233	int blob_len = 0;
2e19e101	234	u32 hash;
e5fb5d2c	235	u32 flags;
2e19e101 SG	236	int i;
	237	int rc;
	238
	239	for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
	240	if (options->hash == tpm2_hash_map[i].crypto_id) {
	241	hash = tpm2_hash_map[i].tpm_id;
	242	break;
	243	}
	244	}
	245
	246	if (i == ARRAY_SIZE(tpm2_hash_map))
	247	return -EINVAL;
	248
f2219745 JB	249	if (!options->keyhandle)
	250	return -EINVAL;
	251
9d5171ea	252	rc = tpm_try_get_ops(chip);
2e19e101 SG	253	if (rc)
	254	return rc;
	255
52ce7d97 JB	256	rc = tpm2_start_auth_session(chip);
	257	if (rc)
	258	goto out_put;
	259
8c657a05 JS	260	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
8c657a05 JS	261	if (rc) {
52ce7d97 JB	262	tpm2_end_auth_session(chip);
52ce7d97 JB	263	goto out_put;
8c657a05 JS	264	}
8c657a05 JS	265
40813f18 JS	266	rc = tpm_buf_init_sized(&sized);
	267	if (rc) {
	268	tpm_buf_destroy(&buf);
52ce7d97 JB	269	tpm2_end_auth_session(chip);
52ce7d97 JB	270	goto out_put;
40813f18 JS	271	}
40813f18 JS	272
52ce7d97 JB	273	tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
	274	tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_DECRYPT,
	275	options->keyauth, TPM_DIGEST_SIZE);
2e19e101 SG	276
2e19e101 SG	277	/* sensitive */
40813f18	278	tpm_buf_append_u16(&sized, options->blobauth_len);
de66514d	279
de66514d	280	if (options->blobauth_len)
40813f18	281	tpm_buf_append(&sized, options->blobauth, options->blobauth_len);
2e19e101	282
40813f18 JS	283	tpm_buf_append_u16(&sized, payload->key_len);
	284	tpm_buf_append(&sized, payload->key, payload->key_len);
	285	tpm_buf_append(&buf, sized.data, sized.length);
2e19e101 SG	286
2e19e101 SG	287	/* public */
40813f18 JS	288	tpm_buf_reset_sized(&sized);
	289	tpm_buf_append_u16(&sized, TPM_ALG_KEYEDHASH);
	290	tpm_buf_append_u16(&sized, hash);
2e19e101	291
e5fb5d2c JB	292	/* key properties */
	293	flags = 0;
	294	flags \|= options->policydigest_len ? 0 : TPM2_OA_USER_WITH_AUTH;
40813f18 JS	295	flags \|= payload->migratable ? 0 : (TPM2_OA_FIXED_TPM \| TPM2_OA_FIXED_PARENT);
40813f18 JS	296	tpm_buf_append_u32(&sized, flags);
e5fb5d2c	297
2e19e101	298	/* policy */
40813f18	299	tpm_buf_append_u16(&sized, options->policydigest_len);
e5fb5d2c	300	if (options->policydigest_len)
40813f18	301	tpm_buf_append(&sized, options->policydigest, options->policydigest_len);
2e19e101 SG	302
2e19e101 SG	303	/* public parameters */
40813f18 JS	304	tpm_buf_append_u16(&sized, TPM_ALG_NULL);
	305	tpm_buf_append_u16(&sized, 0);
	306
	307	tpm_buf_append(&buf, sized.data, sized.length);
2e19e101 SG	308
	309	/* outside info */
	310	tpm_buf_append_u16(&buf, 0);
	311
	312	/* creation PCR */
	313	tpm_buf_append_u32(&buf, 0);
	314
	315	if (buf.flags & TPM_BUF_OVERFLOW) {
	316	rc = -E2BIG;
52ce7d97	317	tpm2_end_auth_session(chip);
2e19e101 SG	318	goto out;
	319	}
	320
52ce7d97	321	tpm_buf_fill_hmac_session(chip, &buf);
8c657a05	322	rc = tpm_transmit_cmd(chip, &buf, 4, "sealing data");
52ce7d97	323	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
2e19e101 SG	324	if (rc)
	325	goto out;
	326
40813f18 JS	327	blob_len = tpm_buf_read_u32(&buf, &offset);
40813f18 JS	328	if (blob_len > MAX_BLOB_SIZE \|\| buf.flags & TPM_BUF_BOUNDARY_ERROR) {
2e19e101 SG	329	rc = -E2BIG;
	330	goto out;
	331	}
40813f18	332	if (buf.length - offset < blob_len) {
2e19e101 SG	333	rc = -EFAULT;
	334	goto out;
	335	}
	336
40813f18	337	blob_len = tpm2_key_encode(payload, options, &buf.data[offset], blob_len);
2e19e101 SG	338
2e19e101 SG	339	out:
40813f18	340	tpm_buf_destroy(&sized);
2e19e101 SG	341	tpm_buf_destroy(&buf);
	342
	343	if (rc > 0) {
	344	if (tpm2_rc_value(rc) == TPM2_RC_HASH)
	345	rc = -EINVAL;
	346	else
	347	rc = -EPERM;
	348	}
f2219745	349	if (blob_len < 0)
b3ad7855 BB	350	rc = blob_len;
	351	else
	352	payload->blob_len = blob_len;
2e19e101	353
52ce7d97	354	out_put:
8c657a05	355	tpm_put_ops(chip);
2e19e101 SG	356	return rc;
	357	}
	358
	359	/**
	360	* tpm2_load_cmd() - execute a TPM2_Load command
	361	*
	362	* @chip: TPM chip to use
	363	* @payload: the key data in clear and encrypted form
	364	* @options: authentication values and other options
	365	* @blob_handle: returned blob handle
	366	*
	367	* Return: 0 on success.
	368	* -E2BIG on wrong payload size.
	369	* -EPERM on tpm error status.
	370	* < 0 error from tpm_send.
	371	*/
	372	static int tpm2_load_cmd(struct tpm_chip *chip,
	373	struct trusted_key_payload *payload,
	374	struct trusted_key_options *options,
	375	u32 *blob_handle)
	376	{
	377	struct tpm_buf buf;
	378	unsigned int private_len;
	379	unsigned int public_len;
	380	unsigned int blob_len;
e5fb5d2c	381	u8 blob, pub;
2e19e101	382	int rc;
e5fb5d2c	383	u32 attrs;
2e19e101	384
f2219745 JB	385	rc = tpm2_key_decode(payload, options, &blob);
	386	if (rc) {
	387	/* old form */
	388	blob = payload->blob;
	389	payload->old_format = 1;
	390	}
	391
	392	/* new format carries keyhandle but old format doesn't */
	393	if (!options->keyhandle)
	394	return -EINVAL;
2e19e101	395
f2219745 JB	396	/* must be big enough for at least the two be16 size counts */
	397	if (payload->blob_len < 4)
	398	return -EINVAL;
	399
	400	private_len = get_unaligned_be16(blob);
	401
	402	/* must be big enough for following public_len */
	403	if (private_len + 2 + 2 > (payload->blob_len))
	404	return -E2BIG;
	405
	406	public_len = get_unaligned_be16(blob + 2 + private_len);
	407	if (private_len + 2 + public_len + 2 > payload->blob_len)
2e19e101 SG	408	return -E2BIG;
2e19e101 SG	409
e5fb5d2c JB	410	pub = blob + 2 + private_len + 2;
	411	/* key attributes are always at offset 4 */
	412	attrs = get_unaligned_be32(pub + 4);
	413
	414	if ((attrs & (TPM2_OA_FIXED_TPM \| TPM2_OA_FIXED_PARENT)) ==
	415	(TPM2_OA_FIXED_TPM \| TPM2_OA_FIXED_PARENT))
	416	payload->migratable = 0;
	417	else
	418	payload->migratable = 1;
	419
2e19e101 SG	420	blob_len = private_len + public_len + 4;
	421	if (blob_len > payload->blob_len)
	422	return -E2BIG;
	423
52ce7d97	424	rc = tpm2_start_auth_session(chip);
2e19e101 SG	425	if (rc)
	426	return rc;
	427
52ce7d97 JB	428	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
	429	if (rc) {
	430	tpm2_end_auth_session(chip);
	431	return rc;
	432	}
	433
	434	tpm_buf_append_name(chip, &buf, options->keyhandle, NULL);
	435	tpm_buf_append_hmac_session(chip, &buf, 0, options->keyauth,
	436	TPM_DIGEST_SIZE);
2e19e101	437
f2219745	438	tpm_buf_append(&buf, blob, blob_len);
2e19e101 SG	439
	440	if (buf.flags & TPM_BUF_OVERFLOW) {
	441	rc = -E2BIG;
52ce7d97	442	tpm2_end_auth_session(chip);
2e19e101 SG	443	goto out;
	444	}
	445
52ce7d97	446	tpm_buf_fill_hmac_session(chip, &buf);
8c657a05	447	rc = tpm_transmit_cmd(chip, &buf, 4, "loading blob");
52ce7d97	448	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
2e19e101 SG	449	if (!rc)
	450	*blob_handle = be32_to_cpup(
	451	(__be32 *) &buf.data[TPM_HEADER_SIZE]);
	452
	453	out:
f2219745 JB	454	if (blob != payload->blob)
f2219745 JB	455	kfree(blob);
2e19e101 SG	456	tpm_buf_destroy(&buf);
	457
	458	if (rc > 0)
	459	rc = -EPERM;
	460
	461	return rc;
	462	}
	463
	464	/**
	465	* tpm2_unseal_cmd() - execute a TPM2_Unload command
	466	*
	467	* @chip: TPM chip to use
	468	* @payload: the key data in clear and encrypted form
	469	* @options: authentication values and other options
	470	* @blob_handle: blob handle
	471	*
	472	* Return: 0 on success
	473	* -EPERM on tpm error status
	474	* < 0 error from tpm_send
	475	*/
	476	static int tpm2_unseal_cmd(struct tpm_chip *chip,
	477	struct trusted_key_payload *payload,
	478	struct trusted_key_options *options,
	479	u32 blob_handle)
	480	{
	481	struct tpm_buf buf;
	482	u16 data_len;
	483	u8 *data;
	484	int rc;
	485
52ce7d97	486	rc = tpm2_start_auth_session(chip);
2e19e101 SG	487	if (rc)
	488	return rc;
	489
52ce7d97 JB	490	rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
	491	if (rc) {
	492	tpm2_end_auth_session(chip);
	493	return rc;
	494	}
	495
	496	tpm_buf_append_name(chip, &buf, blob_handle, NULL);
	497
	498	if (!options->policyhandle) {
	499	tpm_buf_append_hmac_session(chip, &buf, TPM2_SA_ENCRYPT,
	500	options->blobauth,
	501	options->blobauth_len);
	502	} else {
	503	/*
	504	* FIXME: The policy session was generated outside the
	505	* kernel so we don't known the nonce and thus can't
	506	* calculate a HMAC on it. Therefore, the user can
	507	* only really use TPM2_PolicyPassword and we must
	508	* send down the plain text password, which could be
	509	* intercepted. We can still encrypt the returned
	510	* key, but that's small comfort since the interposer
	511	* could repeat our actions with the exfiltrated
	512	* password.
	513	*/
	514	tpm2_buf_append_auth(&buf, options->policyhandle,
	515	NULL /* nonce */, 0, 0,
	516	options->blobauth, options->blobauth_len);
	517	tpm_buf_append_hmac_session_opt(chip, &buf, TPM2_SA_ENCRYPT,
	518	NULL, 0);
	519	}
2e19e101	520
52ce7d97	521	tpm_buf_fill_hmac_session(chip, &buf);
8c657a05	522	rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
52ce7d97	523	rc = tpm_buf_check_hmac_response(chip, &buf, rc);
2e19e101 SG	524	if (rc > 0)
	525	rc = -EPERM;
	526
	527	if (!rc) {
	528	data_len = be16_to_cpup(
	529	(__be16 *) &buf.data[TPM_HEADER_SIZE + 4]);
e5fb5d2c	530	if (data_len < MIN_KEY_SIZE \|\| data_len > MAX_KEY_SIZE) {
2e19e101 SG	531	rc = -EFAULT;
	532	goto out;
	533	}
	534
	535	if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 6 + data_len) {
	536	rc = -EFAULT;
	537	goto out;
	538	}
	539	data = &buf.data[TPM_HEADER_SIZE + 6];
	540
e5fb5d2c JB	541	if (payload->old_format) {
	542	/* migratable flag is at the end of the key */
	543	memcpy(payload->key, data, data_len - 1);
	544	payload->key_len = data_len - 1;
	545	payload->migratable = data[data_len - 1];
	546	} else {
	547	/*
	548	* migratable flag already collected from key
	549	* attributes
	550	*/
	551	memcpy(payload->key, data, data_len);
	552	payload->key_len = data_len;
	553	}
2e19e101 SG	554	}
	555
	556	out:
	557	tpm_buf_destroy(&buf);
	558	return rc;
	559	}
	560
	561	/**
	562	* tpm2_unseal_trusted() - unseal the payload of a trusted key
	563	*
	564	* @chip: TPM chip to use
	565	* @payload: the key data in clear and encrypted form
	566	* @options: authentication values and other options
	567	*
	568	* Return: Same as with tpm_send.
	569	*/
	570	int tpm2_unseal_trusted(struct tpm_chip *chip,
	571	struct trusted_key_payload *payload,
	572	struct trusted_key_options *options)
	573	{
	574	u32 blob_handle;
	575	int rc;
	576
8c657a05	577	rc = tpm_try_get_ops(chip);
2e19e101 SG	578	if (rc)
	579	return rc;
	580
8c657a05 JS	581	rc = tpm2_load_cmd(chip, payload, options, &blob_handle);
	582	if (rc)
	583	goto out;
	584
2e19e101	585	rc = tpm2_unseal_cmd(chip, payload, options, blob_handle);
45477b3f	586	tpm2_flush_context(chip, blob_handle);
2e19e101	587
8c657a05 JS	588	out:
	589	tpm_put_ops(chip);
	590
2e19e101 SG	591	return rc;
2e19e101 SG	592	}