/*
 * 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/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\n", 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\n", hmac_alg);
                return PTR_ERR(sdesc);
        }

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

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

        c = h3;
        ret = crypto_shash_init(&sdesc->shash);
        if (ret < 0)
                goto out;
        va_start(argp, h3);
        for (;;) {
                dlen = va_arg(argp, unsigned int);
                if (dlen == 0)
                        break;
                data = va_arg(argp, unsigned char *);
                if (!data) {
                        ret = -EINVAL;
                        break;
                }
                ret = crypto_shash_update(&sdesc->shash, data, dlen);
                if (ret < 0)
                        break;
        }
        va_end(argp);
        if (!ret)
                ret = crypto_shash_final(&sdesc->shash, paramdigest);
        if (!ret)
                ret = TSS_rawhmac(digest, key, keylen, SHA1_DIGEST_SIZE,
                                  paramdigest, TPM_NONCE_SIZE, h1,
                                  TPM_NONCE_SIZE, h2, 1, &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\n", 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\n", 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)\n", ret);
                return ret;
        }
        ret = oiap(tb, &authhandle2, enonce2);
        if (ret < 0) {
                pr_info("trusted_key: oiap failed (%d)\n", 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)\n", 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)\n", 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)\n", 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)\n", 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)\n", 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;
                        hex2bin(opt->pcrinfo, args[0].from, opt->pcrinfo_len);
                        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;
                        hex2bin(opt->keyauth, args[0].from, SHA1_DIGEST_SIZE);
                        break;
                case Opt_blobauth:
                        if (strlen(args[0].from) != 2 * SHA1_DIGEST_SIZE)
                                return -EINVAL;
                        hex2bin(opt->blobauth, args[0].from, SHA1_DIGEST_SIZE);
                        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;
                hex2bin(p->blob, c, p->blob_len);
                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)\n", 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)\n", ret);
                        goto out;
                }
                ret = key_seal(payload, options);
                if (ret < 0)
                        pr_info("trusted_key: key_seal failed (%d)\n", 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)\n", 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)\n", 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_protected(key->payload.data,
                        rwsem_is_locked(&((struct key *)key)->sem));
        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 = pack_hex_byte(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\n",
                        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\n",
                        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");