/*
   * Copyright (C) 2010 IBM Corporation
   *
   * Author:
   * David Safford <safford@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.
   *

   * See Documentation/security/keys-trusted-encrypted.txt

   */
  
  #include <linux/uaccess.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/parser.h>
  #include <linux/string.h>

  #include <linux/err.h>

  #include <keys/user-type.h>
  #include <keys/trusted-type.h>
  #include <linux/key-type.h>
  #include <linux/rcupdate.h>
  #include <linux/crypto.h>
  #include <crypto/hash.h>
  #include <crypto/sha.h>
  #include <linux/capability.h>
  #include <linux/tpm.h>
  #include <linux/tpm_command.h>

  #include "trusted.h"

  
  static const char hmac_alg[] = "hmac(sha1)";
  static const char hash_alg[] = "sha1";
  
  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;
  	sdesc->shash.flags = 0x0;
  	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("trusted_key: can't alloc %s
  ", hash_alg);
  		return PTR_ERR(sdesc);
  	}
  
  	ret = crypto_shash_digest(&sdesc->shash, data, datalen, digest);
  	kfree(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("trusted_key: can't alloc %s
  ", 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(sdesc);
  	return ret;
  }
  
  /*
   * calculate authorization info fields to send to TPM
   */

  static int TSS_authhmac(unsigned char *digest, const unsigned char *key,

  			unsigned int keylen, unsigned char *h1,

  			unsigned char *h2, unsigned char h3, ...)

  {
  	unsigned char paramdigest[SHA1_DIGEST_SIZE];
  	struct sdesc *sdesc;
  	unsigned int dlen;
  	unsigned char *data;
  	unsigned char c;
  	int ret;
  	va_list argp;
  
  	sdesc = init_sdesc(hashalg);
  	if (IS_ERR(sdesc)) {
  		pr_info("trusted_key: can't alloc %s
  ", 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, &c, 0, 0);

  out:
  	kfree(sdesc);
  	return ret;
  }
  
  /*
   * verify the AUTH1_COMMAND (Seal) result from TPM
   */

  static int TSS_checkhmac1(unsigned char *buffer,
  			  const uint32_t command,
  			  const unsigned char *ononce,
  			  const unsigned char *key,

  			  unsigned int keylen, ...)

  {
  	uint32_t bufsize;
  	uint16_t tag;
  	uint32_t ordinal;
  	uint32_t result;
  	unsigned char *enonce;
  	unsigned char *continueflag;
  	unsigned char *authdata;
  	unsigned char testhmac[SHA1_DIGEST_SIZE];
  	unsigned char paramdigest[SHA1_DIGEST_SIZE];
  	struct sdesc *sdesc;
  	unsigned int dlen;
  	unsigned int dpos;
  	va_list argp;
  	int ret;
  
  	bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
  	tag = LOAD16(buffer, 0);
  	ordinal = command;
  	result = LOAD32N(buffer, TPM_RETURN_OFFSET);
  	if (tag == TPM_TAG_RSP_COMMAND)
  		return 0;
  	if (tag != TPM_TAG_RSP_AUTH1_COMMAND)
  		return -EINVAL;
  	authdata = buffer + bufsize - SHA1_DIGEST_SIZE;
  	continueflag = authdata - 1;
  	enonce = continueflag - TPM_NONCE_SIZE;
  
  	sdesc = init_sdesc(hashalg);
  	if (IS_ERR(sdesc)) {
  		pr_info("trusted_key: can't alloc %s
  ", hash_alg);
  		return PTR_ERR(sdesc);
  	}
  	ret = crypto_shash_init(&sdesc->shash);
  	if (ret < 0)
  		goto out;
  	ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
  				  sizeof result);
  	if (ret < 0)
  		goto out;
  	ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
  				  sizeof ordinal);
  	if (ret < 0)
  		goto out;
  	va_start(argp, keylen);
  	for (;;) {
  		dlen = va_arg(argp, unsigned int);
  		if (dlen == 0)
  			break;
  		dpos = va_arg(argp, unsigned int);
  		ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);

  		if (ret < 0)
  			break;

  	}
  	va_end(argp);

  	if (!ret)
  		ret = crypto_shash_final(&sdesc->shash, paramdigest);

  	if (ret < 0)
  		goto out;

  	ret = TSS_rawhmac(testhmac, key, keylen, SHA1_DIGEST_SIZE, paramdigest,
  			  TPM_NONCE_SIZE, enonce, TPM_NONCE_SIZE, ononce,
  			  1, continueflag, 0, 0);
  	if (ret < 0)
  		goto out;

  	if (memcmp(testhmac, authdata, SHA1_DIGEST_SIZE))
  		ret = -EINVAL;
  out:
  	kfree(sdesc);
  	return ret;
  }
  
  /*
   * verify the AUTH2_COMMAND (unseal) result from TPM
   */

  static int TSS_checkhmac2(unsigned char *buffer,
  			  const uint32_t command,
  			  const unsigned char *ononce,
  			  const unsigned char *key1,

  			  unsigned int keylen1,

  			  const unsigned char *key2,

  			  unsigned int keylen2, ...)

  {
  	uint32_t bufsize;
  	uint16_t tag;
  	uint32_t ordinal;
  	uint32_t result;
  	unsigned char *enonce1;
  	unsigned char *continueflag1;
  	unsigned char *authdata1;
  	unsigned char *enonce2;
  	unsigned char *continueflag2;
  	unsigned char *authdata2;
  	unsigned char testhmac1[SHA1_DIGEST_SIZE];
  	unsigned char testhmac2[SHA1_DIGEST_SIZE];
  	unsigned char paramdigest[SHA1_DIGEST_SIZE];
  	struct sdesc *sdesc;
  	unsigned int dlen;
  	unsigned int dpos;
  	va_list argp;
  	int ret;
  
  	bufsize = LOAD32(buffer, TPM_SIZE_OFFSET);
  	tag = LOAD16(buffer, 0);
  	ordinal = command;
  	result = LOAD32N(buffer, TPM_RETURN_OFFSET);
  
  	if (tag == TPM_TAG_RSP_COMMAND)
  		return 0;
  	if (tag != TPM_TAG_RSP_AUTH2_COMMAND)
  		return -EINVAL;
  	authdata1 = buffer + bufsize - (SHA1_DIGEST_SIZE + 1
  			+ SHA1_DIGEST_SIZE + SHA1_DIGEST_SIZE);
  	authdata2 = buffer + bufsize - (SHA1_DIGEST_SIZE);
  	continueflag1 = authdata1 - 1;
  	continueflag2 = authdata2 - 1;
  	enonce1 = continueflag1 - TPM_NONCE_SIZE;
  	enonce2 = continueflag2 - TPM_NONCE_SIZE;
  
  	sdesc = init_sdesc(hashalg);
  	if (IS_ERR(sdesc)) {
  		pr_info("trusted_key: can't alloc %s
  ", hash_alg);
  		return PTR_ERR(sdesc);
  	}
  	ret = crypto_shash_init(&sdesc->shash);
  	if (ret < 0)
  		goto out;
  	ret = crypto_shash_update(&sdesc->shash, (const u8 *)&result,
  				  sizeof result);
  	if (ret < 0)
  		goto out;
  	ret = crypto_shash_update(&sdesc->shash, (const u8 *)&ordinal,
  				  sizeof ordinal);
  	if (ret < 0)
  		goto out;
  
  	va_start(argp, keylen2);
  	for (;;) {
  		dlen = va_arg(argp, unsigned int);
  		if (dlen == 0)
  			break;
  		dpos = va_arg(argp, unsigned int);
  		ret = crypto_shash_update(&sdesc->shash, buffer + dpos, dlen);

  		if (ret < 0)
  			break;

  	}

  	va_end(argp);

  	if (!ret)
  		ret = crypto_shash_final(&sdesc->shash, paramdigest);

  	if (ret < 0)
  		goto out;
  
  	ret = TSS_rawhmac(testhmac1, key1, keylen1, SHA1_DIGEST_SIZE,
  			  paramdigest, TPM_NONCE_SIZE, enonce1,
  			  TPM_NONCE_SIZE, ononce, 1, continueflag1, 0, 0);

  	if (ret < 0)
  		goto out;

  	if (memcmp(testhmac1, authdata1, SHA1_DIGEST_SIZE)) {
  		ret = -EINVAL;
  		goto out;
  	}
  	ret = TSS_rawhmac(testhmac2, key2, keylen2, SHA1_DIGEST_SIZE,
  			  paramdigest, TPM_NONCE_SIZE, enonce2,
  			  TPM_NONCE_SIZE, ononce, 1, continueflag2, 0, 0);

  	if (ret < 0)
  		goto out;

  	if (memcmp(testhmac2, authdata2, SHA1_DIGEST_SIZE))
  		ret = -EINVAL;
  out:
  	kfree(sdesc);
  	return ret;
  }
  
  /*
   * For key specific tpm requests, we will generate and send our
   * own TPM command packets using the drivers send function.
   */
  static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd,
  			    size_t buflen)
  {
  	int rc;
  
  	dump_tpm_buf(cmd);
  	rc = tpm_send(chip_num, cmd, buflen);
  	dump_tpm_buf(cmd);
  	if (rc > 0)
  		/* Can't return positive return codes values to keyctl */
  		rc = -EPERM;
  	return rc;
  }
  
  /*
   * get a random value from TPM
   */
  static int tpm_get_random(struct tpm_buf *tb, unsigned char *buf, uint32_t len)
  {
  	int ret;
  
  	INIT_BUF(tb);
  	store16(tb, TPM_TAG_RQU_COMMAND);
  	store32(tb, TPM_GETRANDOM_SIZE);
  	store32(tb, TPM_ORD_GETRANDOM);
  	store32(tb, len);
  	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, sizeof tb->data);

  	if (!ret)
  		memcpy(buf, tb->data + TPM_GETRANDOM_SIZE, len);

  	return ret;
  }
  
  static int my_get_random(unsigned char *buf, int len)
  {
  	struct tpm_buf *tb;
  	int ret;

  	tb = kmalloc(sizeof *tb, GFP_KERNEL);

  	if (!tb)
  		return -ENOMEM;
  	ret = tpm_get_random(tb, buf, len);
  
  	kfree(tb);
  	return ret;
  }
  
  /*
   * Lock a trusted key, by extending a selected PCR.
   *
   * Prevents a trusted key that is sealed to PCRs from being accessed.
   * This uses the tpm driver's extend function.
   */
  static int pcrlock(const int pcrnum)
  {
  	unsigned char hash[SHA1_DIGEST_SIZE];

  	int ret;

  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EPERM;

  	ret = my_get_random(hash, SHA1_DIGEST_SIZE);
  	if (ret < 0)
  		return ret;

  	return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
  }
  
  /*
   * Create an object specific authorisation protocol (OSAP) session
   */
  static int osap(struct tpm_buf *tb, struct osapsess *s,

  		const unsigned char *key, uint16_t type, uint32_t handle)

  {
  	unsigned char enonce[TPM_NONCE_SIZE];
  	unsigned char ononce[TPM_NONCE_SIZE];
  	int ret;
  
  	ret = tpm_get_random(tb, ononce, TPM_NONCE_SIZE);
  	if (ret < 0)
  		return ret;
  
  	INIT_BUF(tb);
  	store16(tb, TPM_TAG_RQU_COMMAND);
  	store32(tb, TPM_OSAP_SIZE);
  	store32(tb, TPM_ORD_OSAP);
  	store16(tb, type);
  	store32(tb, handle);
  	storebytes(tb, ononce, TPM_NONCE_SIZE);
  
  	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
  	if (ret < 0)
  		return ret;
  
  	s->handle = LOAD32(tb->data, TPM_DATA_OFFSET);
  	memcpy(s->enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)]),
  	       TPM_NONCE_SIZE);
  	memcpy(enonce, &(tb->data[TPM_DATA_OFFSET + sizeof(uint32_t) +
  				  TPM_NONCE_SIZE]), TPM_NONCE_SIZE);

  	return TSS_rawhmac(s->secret, key, SHA1_DIGEST_SIZE, TPM_NONCE_SIZE,
  			   enonce, TPM_NONCE_SIZE, ononce, 0, 0);

  }
  
  /*
   * Create an object independent authorisation protocol (oiap) session
   */
  static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
  {
  	int ret;
  
  	INIT_BUF(tb);
  	store16(tb, TPM_TAG_RQU_COMMAND);
  	store32(tb, TPM_OIAP_SIZE);
  	store32(tb, TPM_ORD_OIAP);
  	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
  	if (ret < 0)
  		return ret;
  
  	*handle = LOAD32(tb->data, TPM_DATA_OFFSET);
  	memcpy(nonce, &tb->data[TPM_DATA_OFFSET + sizeof(uint32_t)],
  	       TPM_NONCE_SIZE);

  	return 0;

  }
  
  struct tpm_digests {
  	unsigned char encauth[SHA1_DIGEST_SIZE];
  	unsigned char pubauth[SHA1_DIGEST_SIZE];
  	unsigned char xorwork[SHA1_DIGEST_SIZE * 2];
  	unsigned char xorhash[SHA1_DIGEST_SIZE];
  	unsigned char nonceodd[TPM_NONCE_SIZE];
  };
  
  /*
   * Have the TPM seal(encrypt) the trusted key, possibly based on
   * Platform Configuration Registers (PCRs). AUTH1 for sealing key.
   */

  static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
  		    uint32_t keyhandle, const unsigned char *keyauth,
  		    const unsigned char *data, uint32_t datalen,

  		    unsigned char *blob, uint32_t *bloblen,
  		    const unsigned char *blobauth,

  		    const unsigned char *pcrinfo, uint32_t pcrinfosize)

  {
  	struct osapsess sess;
  	struct tpm_digests *td;
  	unsigned char cont;
  	uint32_t ordinal;
  	uint32_t pcrsize;
  	uint32_t datsize;
  	int sealinfosize;
  	int encdatasize;
  	int storedsize;
  	int ret;
  	int i;
  
  	/* alloc some work space for all the hashes */
  	td = kmalloc(sizeof *td, GFP_KERNEL);
  	if (!td)
  		return -ENOMEM;
  
  	/* get session for sealing key */
  	ret = osap(tb, &sess, keyauth, keytype, keyhandle);
  	if (ret < 0)

  		goto out;

  	dump_sess(&sess);
  
  	/* calculate encrypted authorization value */
  	memcpy(td->xorwork, sess.secret, SHA1_DIGEST_SIZE);
  	memcpy(td->xorwork + SHA1_DIGEST_SIZE, sess.enonce, SHA1_DIGEST_SIZE);
  	ret = TSS_sha1(td->xorwork, SHA1_DIGEST_SIZE * 2, td->xorhash);
  	if (ret < 0)

  		goto out;

  
  	ret = tpm_get_random(tb, td->nonceodd, TPM_NONCE_SIZE);
  	if (ret < 0)

  		goto out;

  	ordinal = htonl(TPM_ORD_SEAL);
  	datsize = htonl(datalen);
  	pcrsize = htonl(pcrinfosize);
  	cont = 0;
  
  	/* encrypt data authorization key */
  	for (i = 0; i < SHA1_DIGEST_SIZE; ++i)
  		td->encauth[i] = td->xorhash[i] ^ blobauth[i];
  
  	/* calculate authorization HMAC value */
  	if (pcrinfosize == 0) {
  		/* no pcr info specified */

  		ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
  				   sess.enonce, td->nonceodd, cont,
  				   sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
  				   td->encauth, sizeof(uint32_t), &pcrsize,
  				   sizeof(uint32_t), &datsize, datalen, data, 0,
  				   0);

  	} else {
  		/* pcr info specified */

  		ret = TSS_authhmac(td->pubauth, sess.secret, SHA1_DIGEST_SIZE,
  				   sess.enonce, td->nonceodd, cont,
  				   sizeof(uint32_t), &ordinal, SHA1_DIGEST_SIZE,
  				   td->encauth, sizeof(uint32_t), &pcrsize,
  				   pcrinfosize, pcrinfo, sizeof(uint32_t),
  				   &datsize, datalen, data, 0, 0);

  	}

  	if (ret < 0)

  		goto out;

  
  	/* build and send the TPM request packet */
  	INIT_BUF(tb);
  	store16(tb, TPM_TAG_RQU_AUTH1_COMMAND);
  	store32(tb, TPM_SEAL_SIZE + pcrinfosize + datalen);
  	store32(tb, TPM_ORD_SEAL);
  	store32(tb, keyhandle);
  	storebytes(tb, td->encauth, SHA1_DIGEST_SIZE);
  	store32(tb, pcrinfosize);
  	storebytes(tb, pcrinfo, pcrinfosize);
  	store32(tb, datalen);
  	storebytes(tb, data, datalen);
  	store32(tb, sess.handle);
  	storebytes(tb, td->nonceodd, TPM_NONCE_SIZE);
  	store8(tb, cont);
  	storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
  
  	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
  	if (ret < 0)

  		goto out;

  
  	/* calculate the size of the returned Blob */
  	sealinfosize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t));
  	encdatasize = LOAD32(tb->data, TPM_DATA_OFFSET + sizeof(uint32_t) +
  			     sizeof(uint32_t) + sealinfosize);
  	storedsize = sizeof(uint32_t) + sizeof(uint32_t) + sealinfosize +
  	    sizeof(uint32_t) + encdatasize;
  
  	/* check the HMAC in the response */
  	ret = TSS_checkhmac1(tb->data, ordinal, td->nonceodd, sess.secret,
  			     SHA1_DIGEST_SIZE, storedsize, TPM_DATA_OFFSET, 0,
  			     0);
  
  	/* copy the returned blob to caller */

  	if (!ret) {
  		memcpy(blob, tb->data + TPM_DATA_OFFSET, storedsize);
  		*bloblen = storedsize;
  	}

  out:
  	kfree(td);

  	return ret;
  }
  
  /*
   * use the AUTH2_COMMAND form of unseal, to authorize both key and blob
   */
  static int tpm_unseal(struct tpm_buf *tb,

  		      uint32_t keyhandle, const unsigned char *keyauth,
  		      const unsigned char *blob, int bloblen,

  		      const unsigned char *blobauth,
  		      unsigned char *data, unsigned int *datalen)
  {
  	unsigned char nonceodd[TPM_NONCE_SIZE];
  	unsigned char enonce1[TPM_NONCE_SIZE];
  	unsigned char enonce2[TPM_NONCE_SIZE];
  	unsigned char authdata1[SHA1_DIGEST_SIZE];
  	unsigned char authdata2[SHA1_DIGEST_SIZE];
  	uint32_t authhandle1 = 0;
  	uint32_t authhandle2 = 0;
  	unsigned char cont = 0;
  	uint32_t ordinal;
  	uint32_t keyhndl;
  	int ret;
  
  	/* sessions for unsealing key and data */
  	ret = oiap(tb, &authhandle1, enonce1);
  	if (ret < 0) {
  		pr_info("trusted_key: oiap failed (%d)
  ", ret);
  		return ret;
  	}
  	ret = oiap(tb, &authhandle2, enonce2);
  	if (ret < 0) {
  		pr_info("trusted_key: oiap failed (%d)
  ", ret);
  		return ret;
  	}
  
  	ordinal = htonl(TPM_ORD_UNSEAL);
  	keyhndl = htonl(SRKHANDLE);
  	ret = tpm_get_random(tb, nonceodd, TPM_NONCE_SIZE);
  	if (ret < 0) {
  		pr_info("trusted_key: tpm_get_random failed (%d)
  ", ret);
  		return ret;
  	}

  	ret = TSS_authhmac(authdata1, keyauth, TPM_NONCE_SIZE,
  			   enonce1, nonceodd, cont, sizeof(uint32_t),
  			   &ordinal, bloblen, blob, 0, 0);
  	if (ret < 0)
  		return ret;
  	ret = TSS_authhmac(authdata2, blobauth, TPM_NONCE_SIZE,
  			   enonce2, nonceodd, cont, sizeof(uint32_t),
  			   &ordinal, bloblen, blob, 0, 0);
  	if (ret < 0)
  		return ret;

  
  	/* build and send TPM request packet */
  	INIT_BUF(tb);
  	store16(tb, TPM_TAG_RQU_AUTH2_COMMAND);
  	store32(tb, TPM_UNSEAL_SIZE + bloblen);
  	store32(tb, TPM_ORD_UNSEAL);
  	store32(tb, keyhandle);
  	storebytes(tb, blob, bloblen);
  	store32(tb, authhandle1);
  	storebytes(tb, nonceodd, TPM_NONCE_SIZE);
  	store8(tb, cont);
  	storebytes(tb, authdata1, SHA1_DIGEST_SIZE);
  	store32(tb, authhandle2);
  	storebytes(tb, nonceodd, TPM_NONCE_SIZE);
  	store8(tb, cont);
  	storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
  
  	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
  	if (ret < 0) {
  		pr_info("trusted_key: authhmac failed (%d)
  ", ret);
  		return ret;
  	}
  
  	*datalen = LOAD32(tb->data, TPM_DATA_OFFSET);
  	ret = TSS_checkhmac2(tb->data, ordinal, nonceodd,
  			     keyauth, SHA1_DIGEST_SIZE,
  			     blobauth, SHA1_DIGEST_SIZE,
  			     sizeof(uint32_t), TPM_DATA_OFFSET,
  			     *datalen, TPM_DATA_OFFSET + sizeof(uint32_t), 0,
  			     0);

  	if (ret < 0) {

  		pr_info("trusted_key: TSS_checkhmac2 failed (%d)
  ", ret);

  		return ret;
  	}

  	memcpy(data, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), *datalen);

  	return 0;

  }
  
  /*
   * Have the TPM seal(encrypt) the symmetric key
   */
  static int key_seal(struct trusted_key_payload *p,
  		    struct trusted_key_options *o)
  {
  	struct tpm_buf *tb;
  	int ret;
  
  	tb = kzalloc(sizeof *tb, GFP_KERNEL);
  	if (!tb)
  		return -ENOMEM;
  
  	/* include migratable flag at end of sealed key */
  	p->key[p->key_len] = p->migratable;
  
  	ret = tpm_seal(tb, o->keytype, o->keyhandle, o->keyauth,
  		       p->key, p->key_len + 1, p->blob, &p->blob_len,
  		       o->blobauth, o->pcrinfo, o->pcrinfo_len);
  	if (ret < 0)
  		pr_info("trusted_key: srkseal failed (%d)
  ", ret);
  
  	kfree(tb);
  	return ret;
  }
  
  /*
   * Have the TPM unseal(decrypt) the symmetric key
   */
  static int key_unseal(struct trusted_key_payload *p,
  		      struct trusted_key_options *o)
  {
  	struct tpm_buf *tb;
  	int ret;
  
  	tb = kzalloc(sizeof *tb, GFP_KERNEL);
  	if (!tb)
  		return -ENOMEM;
  
  	ret = tpm_unseal(tb, o->keyhandle, o->keyauth, p->blob, p->blob_len,
  			 o->blobauth, p->key, &p->key_len);

  	if (ret < 0)
  		pr_info("trusted_key: srkunseal failed (%d)
  ", ret);

  	else
  		/* pull migratable flag out of sealed key */
  		p->migratable = p->key[--p->key_len];

  
  	kfree(tb);
  	return ret;
  }
  
  enum {
  	Opt_err = -1,
  	Opt_new, Opt_load, Opt_update,
  	Opt_keyhandle, Opt_keyauth, Opt_blobauth,
  	Opt_pcrinfo, Opt_pcrlock, Opt_migratable
  };
  
  static const match_table_t key_tokens = {
  	{Opt_new, "new"},
  	{Opt_load, "load"},
  	{Opt_update, "update"},
  	{Opt_keyhandle, "keyhandle=%s"},
  	{Opt_keyauth, "keyauth=%s"},
  	{Opt_blobauth, "blobauth=%s"},
  	{Opt_pcrinfo, "pcrinfo=%s"},
  	{Opt_pcrlock, "pcrlock=%s"},
  	{Opt_migratable, "migratable=%s"},
  	{Opt_err, NULL}
  };
  
  /* can have zero or more token= options */
  static int getoptions(char *c, struct trusted_key_payload *pay,
  		      struct trusted_key_options *opt)
  {
  	substring_t args[MAX_OPT_ARGS];
  	char *p = c;
  	int token;
  	int res;
  	unsigned long handle;
  	unsigned long lock;
  
  	while ((p = strsep(&c, " \t"))) {
  		if (*p == '\0' || *p == ' ' || *p == '\t')
  			continue;
  		token = match_token(p, key_tokens, args);
  
  		switch (token) {
  		case Opt_pcrinfo:
  			opt->pcrinfo_len = strlen(args[0].from) / 2;
  			if (opt->pcrinfo_len > MAX_PCRINFO_SIZE)
  				return -EINVAL;

  			res = hex2bin(opt->pcrinfo, args[0].from,
  				      opt->pcrinfo_len);
  			if (res < 0)
  				return -EINVAL;

  			break;
  		case Opt_keyhandle:
  			res = strict_strtoul(args[0].from, 16, &handle);
  			if (res < 0)
  				return -EINVAL;
  			opt->keytype = SEAL_keytype;
  			opt->keyhandle = handle;
  			break;
  		case Opt_keyauth:
  			if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
  				return -EINVAL;

  			res = hex2bin(opt->keyauth, args[0].from,
  				      SHA1_DIGEST_SIZE);
  			if (res < 0)
  				return -EINVAL;

  			break;
  		case Opt_blobauth:
  			if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
  				return -EINVAL;

  			res = hex2bin(opt->blobauth, args[0].from,
  				      SHA1_DIGEST_SIZE);
  			if (res < 0)
  				return -EINVAL;

  			break;
  		case Opt_migratable:
  			if (*args[0].from == '0')
  				pay->migratable = 0;
  			else
  				return -EINVAL;
  			break;
  		case Opt_pcrlock:
  			res = strict_strtoul(args[0].from, 10, &lock);
  			if (res < 0)
  				return -EINVAL;
  			opt->pcrlock = lock;
  			break;
  		default:
  			return -EINVAL;
  		}
  	}
  	return 0;
  }
  
  /*
   * datablob_parse - parse the keyctl data and fill in the
   * 		    payload and options structures
   *
   * On success returns 0, otherwise -EINVAL.
   */
  static int datablob_parse(char *datablob, struct trusted_key_payload *p,
  			  struct trusted_key_options *o)
  {
  	substring_t args[MAX_OPT_ARGS];
  	long keylen;
  	int ret = -EINVAL;
  	int key_cmd;
  	char *c;
  
  	/* main command */
  	c = strsep(&datablob, " \t");
  	if (!c)
  		return -EINVAL;
  	key_cmd = match_token(c, key_tokens, args);
  	switch (key_cmd) {
  	case Opt_new:
  		/* first argument is key size */
  		c = strsep(&datablob, " \t");
  		if (!c)
  			return -EINVAL;
  		ret = strict_strtol(c, 10, &keylen);
  		if (ret < 0 || keylen < MIN_KEY_SIZE || keylen > MAX_KEY_SIZE)
  			return -EINVAL;
  		p->key_len = keylen;
  		ret = getoptions(datablob, p, o);
  		if (ret < 0)
  			return ret;
  		ret = Opt_new;
  		break;
  	case Opt_load:
  		/* first argument is sealed blob */
  		c = strsep(&datablob, " \t");
  		if (!c)
  			return -EINVAL;
  		p->blob_len = strlen(c) / 2;
  		if (p->blob_len > MAX_BLOB_SIZE)
  			return -EINVAL;

  		ret = hex2bin(p->blob, c, p->blob_len);
  		if (ret < 0)
  			return -EINVAL;

  		ret = getoptions(datablob, p, o);
  		if (ret < 0)
  			return ret;
  		ret = Opt_load;
  		break;
  	case Opt_update:
  		/* all arguments are options */
  		ret = getoptions(datablob, p, o);
  		if (ret < 0)
  			return ret;
  		ret = Opt_update;
  		break;
  	case Opt_err:
  		return -EINVAL;
  		break;
  	}
  	return ret;
  }
  
  static struct trusted_key_options *trusted_options_alloc(void)
  {
  	struct trusted_key_options *options;
  
  	options = kzalloc(sizeof *options, GFP_KERNEL);

  	if (options) {
  		/* set any non-zero defaults */
  		options->keytype = SRK_keytype;
  		options->keyhandle = SRKHANDLE;
  	}

  	return options;
  }
  
  static struct trusted_key_payload *trusted_payload_alloc(struct key *key)
  {
  	struct trusted_key_payload *p = NULL;
  	int ret;
  
  	ret = key_payload_reserve(key, sizeof *p);
  	if (ret < 0)
  		return p;
  	p = kzalloc(sizeof *p, GFP_KERNEL);

  	if (p)
  		p->migratable = 1; /* migratable by default */

  	return p;
  }
  
  /*
   * trusted_instantiate - create a new trusted key
   *
   * Unseal an existing trusted blob or, for a new key, get a
   * random key, then seal and create a trusted key-type key,
   * adding it to the specified keyring.
   *
   * On success, return 0. Otherwise return errno.
   */
  static int trusted_instantiate(struct key *key, const void *data,

  			       size_t datalen)

  {
  	struct trusted_key_payload *payload = NULL;
  	struct trusted_key_options *options = NULL;
  	char *datablob;
  	int ret = 0;
  	int key_cmd;
  
  	if (datalen <= 0 || datalen > 32767 || !data)
  		return -EINVAL;
  
  	datablob = kmalloc(datalen + 1, GFP_KERNEL);
  	if (!datablob)
  		return -ENOMEM;
  	memcpy(datablob, data, datalen);
  	datablob[datalen] = '\0';
  
  	options = trusted_options_alloc();
  	if (!options) {
  		ret = -ENOMEM;
  		goto out;
  	}
  	payload = trusted_payload_alloc(key);
  	if (!payload) {
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	key_cmd = datablob_parse(datablob, payload, options);
  	if (key_cmd < 0) {
  		ret = key_cmd;
  		goto out;
  	}
  
  	dump_payload(payload);
  	dump_options(options);
  
  	switch (key_cmd) {
  	case Opt_load:
  		ret = key_unseal(payload, options);
  		dump_payload(payload);
  		dump_options(options);
  		if (ret < 0)
  			pr_info("trusted_key: key_unseal failed (%d)
  ", ret);
  		break;
  	case Opt_new:
  		ret = my_get_random(payload->key, payload->key_len);
  		if (ret < 0) {
  			pr_info("trusted_key: key_create failed (%d)
  ", ret);
  			goto out;
  		}
  		ret = key_seal(payload, options);
  		if (ret < 0)
  			pr_info("trusted_key: key_seal failed (%d)
  ", ret);
  		break;
  	default:
  		ret = -EINVAL;
  		goto out;
  	}
  	if (!ret && options->pcrlock)
  		ret = pcrlock(options->pcrlock);
  out:
  	kfree(datablob);
  	kfree(options);
  	if (!ret)
  		rcu_assign_pointer(key->payload.data, payload);
  	else
  		kfree(payload);
  	return ret;
  }
  
  static void trusted_rcu_free(struct rcu_head *rcu)
  {
  	struct trusted_key_payload *p;
  
  	p = container_of(rcu, struct trusted_key_payload, rcu);
  	memset(p->key, 0, p->key_len);
  	kfree(p);
  }
  
  /*
   * trusted_update - reseal an existing key with new PCR values
   */

  static int trusted_update(struct key *key, const void *data, size_t datalen)

  {
  	struct trusted_key_payload *p = key->payload.data;
  	struct trusted_key_payload *new_p;
  	struct trusted_key_options *new_o;
  	char *datablob;
  	int ret = 0;
  
  	if (!p->migratable)
  		return -EPERM;
  	if (datalen <= 0 || datalen > 32767 || !data)
  		return -EINVAL;
  
  	datablob = kmalloc(datalen + 1, GFP_KERNEL);
  	if (!datablob)
  		return -ENOMEM;
  	new_o = trusted_options_alloc();
  	if (!new_o) {
  		ret = -ENOMEM;
  		goto out;
  	}
  	new_p = trusted_payload_alloc(key);
  	if (!new_p) {
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	memcpy(datablob, data, datalen);
  	datablob[datalen] = '\0';
  	ret = datablob_parse(datablob, new_p, new_o);
  	if (ret != Opt_update) {
  		ret = -EINVAL;

  		kfree(new_p);

  		goto out;
  	}
  	/* copy old key values, and reseal with new pcrs */
  	new_p->migratable = p->migratable;
  	new_p->key_len = p->key_len;
  	memcpy(new_p->key, p->key, p->key_len);
  	dump_payload(p);
  	dump_payload(new_p);
  
  	ret = key_seal(new_p, new_o);
  	if (ret < 0) {
  		pr_info("trusted_key: key_seal failed (%d)
  ", ret);
  		kfree(new_p);
  		goto out;
  	}
  	if (new_o->pcrlock) {
  		ret = pcrlock(new_o->pcrlock);
  		if (ret < 0) {
  			pr_info("trusted_key: pcrlock failed (%d)
  ", ret);
  			kfree(new_p);
  			goto out;
  		}
  	}
  	rcu_assign_pointer(key->payload.data, new_p);
  	call_rcu(&p->rcu, trusted_rcu_free);
  out:
  	kfree(datablob);
  	kfree(new_o);
  	return ret;
  }
  
  /*
   * trusted_read - copy the sealed blob data to userspace in hex.
   * On success, return to userspace the trusted key datablob size.
   */
  static long trusted_read(const struct key *key, char __user *buffer,
  			 size_t buflen)
  {
  	struct trusted_key_payload *p;
  	char *ascii_buf;
  	char *bufp;
  	int i;

  	p = rcu_dereference_key(key);

  	if (!p)
  		return -EINVAL;
  	if (!buffer || buflen <= 0)
  		return 2 * p->blob_len;
  	ascii_buf = kmalloc(2 * p->blob_len, GFP_KERNEL);
  	if (!ascii_buf)
  		return -ENOMEM;
  
  	bufp = ascii_buf;
  	for (i = 0; i < p->blob_len; i++)

  		bufp = hex_byte_pack(bufp, p->blob[i]);

  	if ((copy_to_user(buffer, ascii_buf, 2 * p->blob_len)) != 0) {
  		kfree(ascii_buf);
  		return -EFAULT;
  	}
  	kfree(ascii_buf);
  	return 2 * p->blob_len;
  }
  
  /*
   * trusted_destroy - before freeing the key, clear the decrypted data
   */
  static void trusted_destroy(struct key *key)
  {
  	struct trusted_key_payload *p = key->payload.data;
  
  	if (!p)
  		return;
  	memset(p->key, 0, p->key_len);
  	kfree(key->payload.data);
  }
  
  struct key_type key_type_trusted = {
  	.name = "trusted",
  	.instantiate = trusted_instantiate,
  	.update = trusted_update,
  	.match = user_match,
  	.destroy = trusted_destroy,
  	.describe = user_describe,
  	.read = trusted_read,
  };
  
  EXPORT_SYMBOL_GPL(key_type_trusted);
  
  static void trusted_shash_release(void)
  {
  	if (hashalg)
  		crypto_free_shash(hashalg);
  	if (hmacalg)
  		crypto_free_shash(hmacalg);
  }
  
  static int __init trusted_shash_alloc(void)
  {
  	int ret;
  
  	hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
  	if (IS_ERR(hmacalg)) {
  		pr_info("trusted_key: could not allocate crypto %s
  ",
  			hmac_alg);
  		return PTR_ERR(hmacalg);
  	}
  
  	hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
  	if (IS_ERR(hashalg)) {
  		pr_info("trusted_key: could not allocate crypto %s
  ",
  			hash_alg);
  		ret = PTR_ERR(hashalg);
  		goto hashalg_fail;
  	}
  
  	return 0;
  
  hashalg_fail:
  	crypto_free_shash(hmacalg);
  	return ret;
  }
  
  static int __init init_trusted(void)
  {
  	int ret;
  
  	ret = trusted_shash_alloc();
  	if (ret < 0)
  		return ret;
  	ret = register_key_type(&key_type_trusted);
  	if (ret < 0)
  		trusted_shash_release();
  	return ret;
  }
  
  static void __exit cleanup_trusted(void)
  {
  	trusted_shash_release();
  	unregister_key_type(&key_type_trusted);
  }
  
  late_initcall(init_trusted);
  module_exit(cleanup_trusted);
  
  MODULE_LICENSE("GPL");