// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2014, 2015 Intel Corporation
 *
 * Authors:
 * Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
 *
 * Maintained by: <tpmdd-devel@lists.sourceforge.net>
 *
 * This file contains TPM2 protocol implementations of the commands
 * used by the kernel internally.
 */

#include "tpm.h"
#include <crypto/hash_info.h>
#include <keys/trusted-type.h>

enum tpm2_object_attributes {
        TPM2_OA_USER_WITH_AUTH          = BIT(6),
};

enum tpm2_session_attributes {
        TPM2_SA_CONTINUE_SESSION        = BIT(0),
};

struct tpm2_hash {
        unsigned int crypto_id;
        unsigned int tpm_id;
};

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},
};

int tpm2_get_timeouts(struct tpm_chip *chip)
{
        /* Fixed timeouts for TPM2 */
        chip->timeout_a = msecs_to_jiffies(TPM2_TIMEOUT_A);
        chip->timeout_b = msecs_to_jiffies(TPM2_TIMEOUT_B);
        chip->timeout_c = msecs_to_jiffies(TPM2_TIMEOUT_C);
        chip->timeout_d = msecs_to_jiffies(TPM2_TIMEOUT_D);

        /* PTP spec timeouts */
        chip->duration[TPM_SHORT] = msecs_to_jiffies(TPM2_DURATION_SHORT);
        chip->duration[TPM_MEDIUM] = msecs_to_jiffies(TPM2_DURATION_MEDIUM);
        chip->duration[TPM_LONG] = msecs_to_jiffies(TPM2_DURATION_LONG);

        /* Key creation commands long timeouts */
        chip->duration[TPM_LONG_LONG] =
                msecs_to_jiffies(TPM2_DURATION_LONG_LONG);

        chip->flags |= TPM_CHIP_FLAG_HAVE_TIMEOUTS;

        return 0;
}

/**
 * tpm2_ordinal_duration_index() - returns an index to the chip duration table
 * @ordinal: TPM command ordinal.
 *
 * The function returns an index to the chip duration table
 * (enum tpm_duration), that describes the maximum amount of
 * time the chip could take to return the result for a  particular ordinal.
 *
 * The values of the MEDIUM, and LONG durations are taken
 * from the PC Client Profile (PTP) specification (750, 2000 msec)
 *
 * LONG_LONG is for commands that generates keys which empirically takes
 * a longer time on some systems.
 *
 * Return:
 * * TPM_MEDIUM
 * * TPM_LONG
 * * TPM_LONG_LONG
 * * TPM_UNDEFINED
 */
static u8 tpm2_ordinal_duration_index(u32 ordinal)
{
        switch (ordinal) {
        /* Startup */
        case TPM2_CC_STARTUP:                 /* 144 */
                return TPM_MEDIUM;

        case TPM2_CC_SELF_TEST:               /* 143 */
                return TPM_LONG;

        case TPM2_CC_GET_RANDOM:              /* 17B */
                return TPM_LONG;

        case TPM2_CC_SEQUENCE_UPDATE:         /* 15C */
                return TPM_MEDIUM;
        case TPM2_CC_SEQUENCE_COMPLETE:       /* 13E */
                return TPM_MEDIUM;
        case TPM2_CC_EVENT_SEQUENCE_COMPLETE: /* 185 */
                return TPM_MEDIUM;
        case TPM2_CC_HASH_SEQUENCE_START:     /* 186 */
                return TPM_MEDIUM;

        case TPM2_CC_VERIFY_SIGNATURE:        /* 177 */
                return TPM_LONG;

        case TPM2_CC_PCR_EXTEND:              /* 182 */
                return TPM_MEDIUM;

        case TPM2_CC_HIERARCHY_CONTROL:       /* 121 */
                return TPM_LONG;
        case TPM2_CC_HIERARCHY_CHANGE_AUTH:   /* 129 */
                return TPM_LONG;

        case TPM2_CC_GET_CAPABILITY:          /* 17A */
                return TPM_MEDIUM;

        case TPM2_CC_NV_READ:                 /* 14E */
                return TPM_LONG;

        case TPM2_CC_CREATE_PRIMARY:          /* 131 */
                return TPM_LONG_LONG;
        case TPM2_CC_CREATE:                  /* 153 */
                return TPM_LONG_LONG;
        case TPM2_CC_CREATE_LOADED:           /* 191 */
                return TPM_LONG_LONG;

        default:
                return TPM_UNDEFINED;
        }
}

/**
 * tpm2_calc_ordinal_duration() - calculate the maximum command duration
 * @chip:    TPM chip to use.
 * @ordinal: TPM command ordinal.
 *
 * The function returns the maximum amount of time the chip could take
 * to return the result for a particular ordinal in jiffies.
 *
 * Return: A maximal duration time for an ordinal in jiffies.
 */
unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
{
        unsigned int index;

        index = tpm2_ordinal_duration_index(ordinal);

        if (index != TPM_UNDEFINED)
                return chip->duration[index];
        else
                return msecs_to_jiffies(TPM2_DURATION_DEFAULT);
}


struct tpm2_pcr_read_out {
        __be32  update_cnt;
        __be32  pcr_selects_cnt;
        __be16  hash_alg;
        u8      pcr_select_size;
        u8      pcr_select[TPM2_PCR_SELECT_MIN];
        __be32  digests_cnt;
        __be16  digest_size;
        u8      digest[];
} __packed;

/**
 * tpm2_pcr_read() - read a PCR value
 * @chip:       TPM chip to use.
 * @pcr_idx:    index of the PCR to read.
 * @digest:     PCR bank and buffer current PCR value is written to.
 * @digest_size_ptr:    pointer to variable that stores the digest size.
 *
 * Return: Same as with tpm_transmit_cmd.
 */
int tpm2_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
                  struct tpm_digest *digest, u16 *digest_size_ptr)
{
        int i;
        int rc;
        struct tpm_buf buf;
        struct tpm2_pcr_read_out *out;
        u8 pcr_select[TPM2_PCR_SELECT_MIN] = {0};
        u16 digest_size;
        u16 expected_digest_size = 0;

        if (pcr_idx >= TPM2_PLATFORM_PCR)
                return -EINVAL;

        if (!digest_size_ptr) {
                for (i = 0; i < chip->nr_allocated_banks &&
                     chip->allocated_banks[i].alg_id != digest->alg_id; i++)
                        ;

                if (i == chip->nr_allocated_banks)
                        return -EINVAL;

                expected_digest_size = chip->allocated_banks[i].digest_size;
        }

        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
        if (rc)
                return rc;

        pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);

        tpm_buf_append_u32(&buf, 1);
        tpm_buf_append_u16(&buf, digest->alg_id);
        tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN);
        tpm_buf_append(&buf, (const unsigned char *)pcr_select,
                       sizeof(pcr_select));

        rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to read a pcr value");
        if (rc)
                goto out;

        out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
        digest_size = be16_to_cpu(out->digest_size);
        if (digest_size > sizeof(digest->digest) ||
            (!digest_size_ptr && digest_size != expected_digest_size)) {
                rc = -EINVAL;
                goto out;
        }

        if (digest_size_ptr)
                *digest_size_ptr = digest_size;

        memcpy(digest->digest, out->digest, digest_size);
out:
        tpm_buf_destroy(&buf);
        return rc;
}

struct tpm2_null_auth_area {
        __be32  handle;
        __be16  nonce_size;
        u8  attributes;
        __be16  auth_size;
} __packed;

/**
 * tpm2_pcr_extend() - extend a PCR value
 *
 * @chip:       TPM chip to use.
 * @pcr_idx:    index of the PCR.
 * @digests:    list of pcr banks and corresponding digest values to extend.
 *
 * Return: Same as with tpm_transmit_cmd.
 */
int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
                    struct tpm_digest *digests)
{
        struct tpm_buf buf;
        struct tpm2_null_auth_area auth_area;
        int rc;
        int i;

        rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
        if (rc)
                return rc;

        tpm_buf_append_u32(&buf, pcr_idx);

        auth_area.handle = cpu_to_be32(TPM2_RS_PW);
        auth_area.nonce_size = 0;
        auth_area.attributes = 0;
        auth_area.auth_size = 0;

        tpm_buf_append_u32(&buf, sizeof(struct tpm2_null_auth_area));
        tpm_buf_append(&buf, (const unsigned char *)&auth_area,
                       sizeof(auth_area));
        tpm_buf_append_u32(&buf, chip->nr_allocated_banks);

        for (i = 0; i < chip->nr_allocated_banks; i++) {
                tpm_buf_append_u16(&buf, digests[i].alg_id);
                tpm_buf_append(&buf, (const unsigned char *)&digests[i].digest,
                               chip->allocated_banks[i].digest_size);
        }

        rc = tpm_transmit_cmd(chip, &buf, 0, "attempting extend a PCR value");

        tpm_buf_destroy(&buf);

        return rc;
}

struct tpm2_get_random_out {
        __be16 size;
        u8 buffer[TPM_MAX_RNG_DATA];
} __packed;

/**
 * tpm2_get_random() - get random bytes from the TPM RNG
 *
 * @chip:       a &tpm_chip instance
 * @dest:       destination buffer
 * @max:        the max number of random bytes to pull
 *
 * Return:
 *   size of the buffer on success,
 *   -errno otherwise (positive TPM return codes are masked to -EIO)
 */
int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max)
{
        struct tpm2_get_random_out *out;
        struct tpm_buf buf;
        u32 recd;
        u32 num_bytes = max;
        int err;
        int total = 0;
        int retries = 5;
        u8 *dest_ptr = dest;

        if (!num_bytes || max > TPM_MAX_RNG_DATA)
                return -EINVAL;

        err = tpm_buf_init(&buf, 0, 0);
        if (err)
                return err;

        do {
                tpm_buf_reset(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_RANDOM);
                tpm_buf_append_u16(&buf, num_bytes);
                err = tpm_transmit_cmd(chip, &buf,
                                       offsetof(struct tpm2_get_random_out,
                                                buffer),
                                       "attempting get random");
                if (err) {
                        if (err > 0)
                                err = -EIO;
                        goto out;
                }

                out = (struct tpm2_get_random_out *)
                        &buf.data[TPM_HEADER_SIZE];
                recd = min_t(u32, be16_to_cpu(out->size), num_bytes);
                if (tpm_buf_length(&buf) <
                    TPM_HEADER_SIZE +
                    offsetof(struct tpm2_get_random_out, buffer) +
                    recd) {
                        err = -EFAULT;
                        goto out;
                }
                memcpy(dest_ptr, out->buffer, recd);

                dest_ptr += recd;
                total += recd;
                num_bytes -= recd;
        } while (retries-- && total < max);

        tpm_buf_destroy(&buf);
        return total ? total : -EIO;
out:
        tpm_buf_destroy(&buf);
        return err;
}

/**
 * tpm2_flush_context() - execute a TPM2_FlushContext command
 * @chip:       TPM chip to use
 * @handle:     context handle
 */
void tpm2_flush_context(struct tpm_chip *chip, u32 handle)
{
        struct tpm_buf buf;
        int rc;

        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_FLUSH_CONTEXT);
        if (rc) {
                dev_warn(&chip->dev, "0x%08x was not flushed, out of memory\n",
                         handle);
                return;
        }

        tpm_buf_append_u32(&buf, handle);

        tpm_transmit_cmd(chip, &buf, 0, "flushing context");
        tpm_buf_destroy(&buf);
}

/**
 * tpm_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)
{
        unsigned int blob_len;
        struct tpm_buf buf;
        u32 hash;
        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;

        rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_CREATE);
        if (rc)
                return rc;

        tpm_buf_append_u32(&buf, options->keyhandle);
        tpm2_buf_append_auth(&buf, TPM2_RS_PW,
                             NULL /* nonce */, 0,
                             0 /* session_attributes */,
                             options->keyauth /* hmac */,
                             TPM_DIGEST_SIZE);

        /* sensitive */
        tpm_buf_append_u16(&buf, 4 + TPM_DIGEST_SIZE + payload->key_len + 1);

        tpm_buf_append_u16(&buf, TPM_DIGEST_SIZE);
        tpm_buf_append(&buf, options->blobauth, TPM_DIGEST_SIZE);
        tpm_buf_append_u16(&buf, payload->key_len + 1);
        tpm_buf_append(&buf, payload->key, payload->key_len);
        tpm_buf_append_u8(&buf, payload->migratable);

        /* public */
        tpm_buf_append_u16(&buf, 14 + options->policydigest_len);
        tpm_buf_append_u16(&buf, TPM_ALG_KEYEDHASH);
        tpm_buf_append_u16(&buf, hash);

        /* policy */
        if (options->policydigest_len) {
                tpm_buf_append_u32(&buf, 0);
                tpm_buf_append_u16(&buf, options->policydigest_len);
                tpm_buf_append(&buf, options->policydigest,
                               options->policydigest_len);
        } else {
                tpm_buf_append_u32(&buf, TPM2_OA_USER_WITH_AUTH);
                tpm_buf_append_u16(&buf, 0);
        }

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

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

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

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

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

        blob_len = be32_to_cpup((__be32 *) &buf.data[TPM_HEADER_SIZE]);
        if (blob_len > MAX_BLOB_SIZE) {
                rc = -E2BIG;
                goto out;
        }
        if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) {
                rc = -EFAULT;
                goto out;
        }

        memcpy(payload->blob, &buf.data[TPM_HEADER_SIZE + 4], blob_len);
        payload->blob_len = blob_len;

out:
        tpm_buf_destroy(&buf);

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

        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_transmit_cmd.
 */
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;
        int rc;

        private_len = be16_to_cpup((__be16 *) &payload->blob[0]);
        if (private_len > (payload->blob_len - 2))
                return -E2BIG;

        public_len = be16_to_cpup((__be16 *) &payload->blob[2 + private_len]);
        blob_len = private_len + public_len + 4;
        if (blob_len > payload->blob_len)
                return -E2BIG;

        rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_LOAD);
        if (rc)
                return rc;

        tpm_buf_append_u32(&buf, options->keyhandle);
        tpm2_buf_append_auth(&buf, TPM2_RS_PW,
                             NULL /* nonce */, 0,
                             0 /* session_attributes */,
                             options->keyauth /* hmac */,
                             TPM_DIGEST_SIZE);

        tpm_buf_append(&buf, payload->blob, blob_len);

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

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

out:
        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_transmit_cmd
 */
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 = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_UNSEAL);
        if (rc)
                return rc;

        tpm_buf_append_u32(&buf, blob_handle);
        tpm2_buf_append_auth(&buf,
                             options->policyhandle ?
                             options->policyhandle : TPM2_RS_PW,
                             NULL /* nonce */, 0,
                             TPM2_SA_CONTINUE_SESSION,
                             options->blobauth /* hmac */,
                             TPM_DIGEST_SIZE);

        rc = tpm_transmit_cmd(chip, &buf, 6, "unsealing");
        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 + 1) {
                        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];

                memcpy(payload->key, data, data_len - 1);
                payload->key_len = data_len - 1;
                payload->migratable = data[data_len - 1];
        }

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_transmit_cmd.
 */
int tpm2_unseal_trusted(struct tpm_chip *chip,
                        struct trusted_key_payload *payload,
                        struct trusted_key_options *options)
{
        u32 blob_handle;
        int rc;

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

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

struct tpm2_get_cap_out {
        u8 more_data;
        __be32 subcap_id;
        __be32 property_cnt;
        __be32 property_id;
        __be32 value;
} __packed;

/**
 * tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
 * @chip:               a &tpm_chip instance
 * @property_id:        property ID.
 * @value:              output variable.
 * @desc:               passed to tpm_transmit_cmd()
 *
 * Return:
 *   0 on success,
 *   -errno or a TPM return code otherwise
 */
ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,  u32 *value,
                        const char *desc)
{
        struct tpm2_get_cap_out *out;
        struct tpm_buf buf;
        int rc;

        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
        if (rc)
                return rc;
        tpm_buf_append_u32(&buf, TPM2_CAP_TPM_PROPERTIES);
        tpm_buf_append_u32(&buf, property_id);
        tpm_buf_append_u32(&buf, 1);
        rc = tpm_transmit_cmd(chip, &buf, 0, NULL);
        if (!rc) {
                out = (struct tpm2_get_cap_out *)
                        &buf.data[TPM_HEADER_SIZE];
                *value = be32_to_cpu(out->value);
        }
        tpm_buf_destroy(&buf);
        return rc;
}
EXPORT_SYMBOL_GPL(tpm2_get_tpm_pt);

/**
 * tpm2_shutdown() - send a TPM shutdown command
 *
 * Sends a TPM shutdown command. The shutdown command is used in call
 * sites where the system is going down. If it fails, there is not much
 * that can be done except print an error message.
 *
 * @chip:               a &tpm_chip instance
 * @shutdown_type:      TPM_SU_CLEAR or TPM_SU_STATE.
 */
void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
{
        struct tpm_buf buf;
        int rc;

        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SHUTDOWN);
        if (rc)
                return;
        tpm_buf_append_u16(&buf, shutdown_type);
        tpm_transmit_cmd(chip, &buf, 0, "stopping the TPM");
        tpm_buf_destroy(&buf);
}

/**
 * tpm2_do_selftest() - ensure that all self tests have passed
 *
 * @chip: TPM chip to use
 *
 * Return: Same as with tpm_transmit_cmd.
 *
 * The TPM can either run all self tests synchronously and then return
 * RC_SUCCESS once all tests were successful. Or it can choose to run the tests
 * asynchronously and return RC_TESTING immediately while the self tests still
 * execute in the background. This function handles both cases and waits until
 * all tests have completed.
 */
static int tpm2_do_selftest(struct tpm_chip *chip)
{
        struct tpm_buf buf;
        int full;
        int rc;

        for (full = 0; full < 2; full++) {
                rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_SELF_TEST);
                if (rc)
                        return rc;

                tpm_buf_append_u8(&buf, full);
                rc = tpm_transmit_cmd(chip, &buf, 0,
                                      "attempting the self test");
                tpm_buf_destroy(&buf);

                if (rc == TPM2_RC_TESTING)
                        rc = TPM2_RC_SUCCESS;
                if (rc == TPM2_RC_INITIALIZE || rc == TPM2_RC_SUCCESS)
                        return rc;
        }

        return rc;
}

/**
 * tpm2_probe() - probe for the TPM 2.0 protocol
 * @chip:       a &tpm_chip instance
 *
 * Send an idempotent TPM 2.0 command and see whether there is TPM2 chip in the
 * other end based on the response tag. The flag TPM_CHIP_FLAG_TPM2 is set by
 * this function if this is the case.
 *
 * Return:
 *   0 on success,
 *   -errno otherwise
 */
int tpm2_probe(struct tpm_chip *chip)
{
        struct tpm_header *out;
        struct tpm_buf buf;
        int rc;

        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
        if (rc)
                return rc;
        tpm_buf_append_u32(&buf, TPM2_CAP_TPM_PROPERTIES);
        tpm_buf_append_u32(&buf, TPM_PT_TOTAL_COMMANDS);
        tpm_buf_append_u32(&buf, 1);
        rc = tpm_transmit_cmd(chip, &buf, 0, NULL);
        /* We ignore TPM return codes on purpose. */
        if (rc >=  0) {
                out = (struct tpm_header *)buf.data;
                if (be16_to_cpu(out->tag) == TPM2_ST_NO_SESSIONS)
                        chip->flags |= TPM_CHIP_FLAG_TPM2;
        }
        tpm_buf_destroy(&buf);
        return 0;
}
EXPORT_SYMBOL_GPL(tpm2_probe);

static int tpm2_init_bank_info(struct tpm_chip *chip, u32 bank_index)
{
        struct tpm_bank_info *bank = chip->allocated_banks + bank_index;
        struct tpm_digest digest = { .alg_id = bank->alg_id };
        int i;

        /*
         * Avoid unnecessary PCR read operations to reduce overhead
         * and obtain identifiers of the crypto subsystem.
         */
        for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
                enum hash_algo crypto_algo = tpm2_hash_map[i].crypto_id;

                if (bank->alg_id != tpm2_hash_map[i].tpm_id)
                        continue;

                bank->digest_size = hash_digest_size[crypto_algo];
                bank->crypto_id = crypto_algo;
                return 0;
        }

        return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
}

struct tpm2_pcr_selection {
        __be16  hash_alg;
        u8  size_of_select;
        u8  pcr_select[3];
} __packed;

ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
{
        struct tpm2_pcr_selection pcr_selection;
        struct tpm_buf buf;
        void *marker;
        void *end;
        void *pcr_select_offset;
        u32 sizeof_pcr_selection;
        u32 nr_possible_banks;
        u32 nr_alloc_banks = 0;
        u16 hash_alg;
        u32 rsp_len;
        int rc;
        int i = 0;

        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
        if (rc)
                return rc;

        tpm_buf_append_u32(&buf, TPM2_CAP_PCRS);
        tpm_buf_append_u32(&buf, 0);
        tpm_buf_append_u32(&buf, 1);

        rc = tpm_transmit_cmd(chip, &buf, 9, "get tpm pcr allocation");
        if (rc)
                goto out;

        nr_possible_banks = be32_to_cpup(
                (__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);

        chip->allocated_banks = kcalloc(nr_possible_banks,
                                        sizeof(*chip->allocated_banks),
                                        GFP_KERNEL);
        if (!chip->allocated_banks) {
                rc = -ENOMEM;
                goto out;
        }

        marker = &buf.data[TPM_HEADER_SIZE + 9];

        rsp_len = be32_to_cpup((__be32 *)&buf.data[2]);
        end = &buf.data[rsp_len];

        for (i = 0; i < nr_possible_banks; i++) {
                pcr_select_offset = marker +
                        offsetof(struct tpm2_pcr_selection, size_of_select);
                if (pcr_select_offset >= end) {
                        rc = -EFAULT;
                        break;
                }

                memcpy(&pcr_selection, marker, sizeof(pcr_selection));
                hash_alg = be16_to_cpu(pcr_selection.hash_alg);

                pcr_select_offset = memchr_inv(pcr_selection.pcr_select, 0,
                                               pcr_selection.size_of_select);
                if (pcr_select_offset) {
                        chip->allocated_banks[nr_alloc_banks].alg_id = hash_alg;

                        rc = tpm2_init_bank_info(chip, nr_alloc_banks);
                        if (rc < 0)
                                break;

                        nr_alloc_banks++;
                }

                sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +
                        sizeof(pcr_selection.size_of_select) +
                        pcr_selection.size_of_select;
                marker = marker + sizeof_pcr_selection;
        }

        chip->nr_allocated_banks = nr_alloc_banks;
out:
        tpm_buf_destroy(&buf);

        return rc;
}

static int tpm2_get_cc_attrs_tbl(struct tpm_chip *chip)
{
        struct tpm_buf buf;
        u32 nr_commands;
        __be32 *attrs;
        u32 cc;
        int i;
        int rc;

        rc = tpm2_get_tpm_pt(chip, TPM_PT_TOTAL_COMMANDS, &nr_commands, NULL);
        if (rc)
                goto out;

        if (nr_commands > 0xFFFFF) {
                rc = -EFAULT;
                goto out;
        }

        chip->cc_attrs_tbl = devm_kcalloc(&chip->dev, 4, nr_commands,
                                          GFP_KERNEL);

        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
        if (rc)
                goto out;

        tpm_buf_append_u32(&buf, TPM2_CAP_COMMANDS);
        tpm_buf_append_u32(&buf, TPM2_CC_FIRST);
        tpm_buf_append_u32(&buf, nr_commands);

        rc = tpm_transmit_cmd(chip, &buf, 9 + 4 * nr_commands, NULL);
        if (rc) {
                tpm_buf_destroy(&buf);
                goto out;
        }

        if (nr_commands !=
            be32_to_cpup((__be32 *)&buf.data[TPM_HEADER_SIZE + 5])) {
                tpm_buf_destroy(&buf);
                goto out;
        }

        chip->nr_commands = nr_commands;

        attrs = (__be32 *)&buf.data[TPM_HEADER_SIZE + 9];
        for (i = 0; i < nr_commands; i++, attrs++) {
                chip->cc_attrs_tbl[i] = be32_to_cpup(attrs);
                cc = chip->cc_attrs_tbl[i] & 0xFFFF;

                if (cc == TPM2_CC_CONTEXT_SAVE || cc == TPM2_CC_FLUSH_CONTEXT) {
                        chip->cc_attrs_tbl[i] &=
                                ~(GENMASK(2, 0) << TPM2_CC_ATTR_CHANDLES);
                        chip->cc_attrs_tbl[i] |= 1 << TPM2_CC_ATTR_CHANDLES;
                }
        }

        tpm_buf_destroy(&buf);

out:
        if (rc > 0)
                rc = -ENODEV;
        return rc;
}

/**
 * tpm2_startup - turn on the TPM
 * @chip: TPM chip to use
 *
 * Normally the firmware should start the TPM. This function is provided as a
 * workaround if this does not happen. A legal case for this could be for
 * example when a TPM emulator is used.
 *
 * Return: same as tpm_transmit_cmd()
 */

static int tpm2_startup(struct tpm_chip *chip)
{
        struct tpm_buf buf;
        int rc;

        dev_info(&chip->dev, "starting up the TPM manually\n");

        rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_STARTUP);
        if (rc < 0)
                return rc;

        tpm_buf_append_u16(&buf, TPM2_SU_CLEAR);
        rc = tpm_transmit_cmd(chip, &buf, 0, "attempting to start the TPM");
        tpm_buf_destroy(&buf);

        return rc;
}

/**
 * tpm2_auto_startup - Perform the standard automatic TPM initialization
 *                     sequence
 * @chip: TPM chip to use
 *
 * Returns 0 on success, < 0 in case of fatal error.
 */
int tpm2_auto_startup(struct tpm_chip *chip)
{
        int rc;

        rc = tpm2_get_timeouts(chip);
        if (rc)
                goto out;

        rc = tpm2_do_selftest(chip);
        if (rc && rc != TPM2_RC_INITIALIZE)
                goto out;

        if (rc == TPM2_RC_INITIALIZE) {
                rc = tpm2_startup(chip);
                if (rc)
                        goto out;

                rc = tpm2_do_selftest(chip);
                if (rc)
                        goto out;
        }

        rc = tpm2_get_cc_attrs_tbl(chip);

out:
        if (rc > 0)
                rc = -ENODEV;
        return rc;
}

int tpm2_find_cc(struct tpm_chip *chip, u32 cc)
{
        int i;

        for (i = 0; i < chip->nr_commands; i++)
                if (cc == (chip->cc_attrs_tbl[i] & GENMASK(15, 0)))
                        return i;

        return -1;
}