/* * Copyright (C) 2004 IBM Corporation * Copyright (C) 2014 Intel Corporation * * Authors: * Leendert van Doorn * Dave Safford * Reiner Sailer * Kylene Hall * * Maintained by: * * Device driver for TCG/TCPA TPM (trusted platform module). * Specifications at www.trustedcomputinggroup.org * * 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. * * Note, the TPM chip is not interrupt driven (only polling) * and can have very long timeouts (minutes!). Hence the unusual * calls to msleep. * */ #include #include #include #include #include #include #include "tpm.h" /* * Bug workaround - some TPM's don't flush the most * recently changed pcr on suspend, so force the flush * with an extend to the selected _unused_ non-volatile pcr. */ static u32 tpm_suspend_pcr; module_param_named(suspend_pcr, tpm_suspend_pcr, uint, 0644); MODULE_PARM_DESC(suspend_pcr, "PCR to use for dummy writes to facilitate flush on suspend."); /** * tpm_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 tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal) { if (chip->flags & TPM_CHIP_FLAG_TPM2) return tpm2_calc_ordinal_duration(chip, ordinal); else return tpm1_calc_ordinal_duration(chip, ordinal); } EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration); static int tpm_validate_command(struct tpm_chip *chip, struct tpm_space *space, const u8 *cmd, size_t len) { const struct tpm_input_header *header = (const void *)cmd; int i; u32 cc; u32 attrs; unsigned int nr_handles; if (len < TPM_HEADER_SIZE) return -EINVAL; if (!space) return 0; if (chip->flags & TPM_CHIP_FLAG_TPM2 && chip->nr_commands) { cc = be32_to_cpu(header->ordinal); i = tpm2_find_cc(chip, cc); if (i < 0) { dev_dbg(&chip->dev, "0x%04X is an invalid command\n", cc); return -EOPNOTSUPP; } attrs = chip->cc_attrs_tbl[i]; nr_handles = 4 * ((attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0)); if (len < TPM_HEADER_SIZE + 4 * nr_handles) goto err_len; } return 0; err_len: dev_dbg(&chip->dev, "%s: insufficient command length %zu", __func__, len); return -EINVAL; } static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags) { int rc; if (flags & TPM_TRANSMIT_NESTED) return 0; if (!chip->ops->request_locality) return 0; rc = chip->ops->request_locality(chip, 0); if (rc < 0) return rc; chip->locality = rc; return 0; } static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags) { int rc; if (flags & TPM_TRANSMIT_NESTED) return; if (!chip->ops->relinquish_locality) return; rc = chip->ops->relinquish_locality(chip, chip->locality); if (rc) dev_err(&chip->dev, "%s: : error %d\n", __func__, rc); chip->locality = -1; } static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags) { if (flags & TPM_TRANSMIT_NESTED) return 0; if (!chip->ops->cmd_ready) return 0; return chip->ops->cmd_ready(chip); } static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags) { if (flags & TPM_TRANSMIT_NESTED) return 0; if (!chip->ops->go_idle) return 0; return chip->ops->go_idle(chip); } static ssize_t tpm_try_transmit(struct tpm_chip *chip, struct tpm_space *space, u8 *buf, size_t bufsiz, unsigned int flags) { struct tpm_output_header *header = (void *)buf; int rc; ssize_t len = 0; u32 count, ordinal; unsigned long stop; bool need_locality; rc = tpm_validate_command(chip, space, buf, bufsiz); if (rc == -EINVAL) return rc; /* * If the command is not implemented by the TPM, synthesize a * response with a TPM2_RC_COMMAND_CODE return for user-space. */ if (rc == -EOPNOTSUPP) { header->length = cpu_to_be32(sizeof(*header)); header->tag = cpu_to_be16(TPM2_ST_NO_SESSIONS); header->return_code = cpu_to_be32(TPM2_RC_COMMAND_CODE | TSS2_RESMGR_TPM_RC_LAYER); return sizeof(*header); } if (bufsiz > TPM_BUFSIZE) bufsiz = TPM_BUFSIZE; count = be32_to_cpu(*((__be32 *) (buf + 2))); ordinal = be32_to_cpu(*((__be32 *) (buf + 6))); if (count == 0) return -ENODATA; if (count > bufsiz) { dev_err(&chip->dev, "invalid count value %x %zx\n", count, bufsiz); return -E2BIG; } if (!(flags & TPM_TRANSMIT_UNLOCKED) && !(flags & TPM_TRANSMIT_NESTED)) mutex_lock(&chip->tpm_mutex); if (chip->ops->clk_enable != NULL) chip->ops->clk_enable(chip, true); /* Store the decision as chip->locality will be changed. */ need_locality = chip->locality == -1; if (need_locality) { rc = tpm_request_locality(chip, flags); if (rc < 0) { need_locality = false; goto out_locality; } } rc = tpm_cmd_ready(chip, flags); if (rc) goto out_locality; rc = tpm2_prepare_space(chip, space, ordinal, buf); if (rc) goto out; rc = chip->ops->send(chip, buf, count); if (rc < 0) { if (rc != -EPIPE) dev_err(&chip->dev, "%s: tpm_send: error %d\n", __func__, rc); goto out; } if (chip->flags & TPM_CHIP_FLAG_IRQ) goto out_recv; stop = jiffies + tpm_calc_ordinal_duration(chip, ordinal); do { u8 status = chip->ops->status(chip); if ((status & chip->ops->req_complete_mask) == chip->ops->req_complete_val) goto out_recv; if (chip->ops->req_canceled(chip, status)) { dev_err(&chip->dev, "Operation Canceled\n"); rc = -ECANCELED; goto out; } tpm_msleep(TPM_TIMEOUT_POLL); rmb(); } while (time_before(jiffies, stop)); chip->ops->cancel(chip); dev_err(&chip->dev, "Operation Timed out\n"); rc = -ETIME; goto out; out_recv: len = chip->ops->recv(chip, buf, bufsiz); if (len < 0) { rc = len; dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc); goto out; } else if (len < TPM_HEADER_SIZE) { rc = -EFAULT; goto out; } if (len != be32_to_cpu(header->length)) { rc = -EFAULT; goto out; } rc = tpm2_commit_space(chip, space, ordinal, buf, &len); if (rc) dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc); out: /* may fail but do not override previous error value in rc */ tpm_go_idle(chip, flags); out_locality: if (need_locality) tpm_relinquish_locality(chip, flags); if (chip->ops->clk_enable != NULL) chip->ops->clk_enable(chip, false); if (!(flags & TPM_TRANSMIT_UNLOCKED) && !(flags & TPM_TRANSMIT_NESTED)) mutex_unlock(&chip->tpm_mutex); return rc ? rc : len; } /** * tpm_transmit - Internal kernel interface to transmit TPM commands. * * @chip: TPM chip to use * @space: tpm space * @buf: TPM command buffer * @bufsiz: length of the TPM command buffer * @flags: tpm transmit flags - bitmap * * A wrapper around tpm_try_transmit that handles TPM2_RC_RETRY * returns from the TPM and retransmits the command after a delay up * to a maximum wait of TPM2_DURATION_LONG. * * Note: TPM1 never returns TPM2_RC_RETRY so the retry logic is TPM2 * only * * Return: * the length of the return when the operation is successful. * A negative number for system errors (errno). */ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, u8 *buf, size_t bufsiz, unsigned int flags) { struct tpm_output_header *header = (struct tpm_output_header *)buf; /* space for header and handles */ u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)]; unsigned int delay_msec = TPM2_DURATION_SHORT; u32 rc = 0; ssize_t ret; const size_t save_size = min(space ? sizeof(save) : TPM_HEADER_SIZE, bufsiz); /* the command code is where the return code will be */ u32 cc = be32_to_cpu(header->return_code); /* * Subtlety here: if we have a space, the handles will be * transformed, so when we restore the header we also have to * restore the handles. */ memcpy(save, buf, save_size); for (;;) { ret = tpm_try_transmit(chip, space, buf, bufsiz, flags); if (ret < 0) break; rc = be32_to_cpu(header->return_code); if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING) break; /* * return immediately if self test returns test * still running to shorten boot time. */ if (rc == TPM2_RC_TESTING && cc == TPM2_CC_SELF_TEST) break; if (delay_msec > TPM2_DURATION_LONG) { if (rc == TPM2_RC_RETRY) dev_err(&chip->dev, "in retry loop\n"); else dev_err(&chip->dev, "self test is still running\n"); break; } tpm_msleep(delay_msec); delay_msec *= 2; memcpy(buf, save, save_size); } return ret; } /** * tpm_transmit_cmd - send a tpm command to the device * The function extracts tpm out header return code * * @chip: TPM chip to use * @space: tpm space * @buf: TPM command buffer * @bufsiz: length of the buffer * @min_rsp_body_length: minimum expected length of response body * @flags: tpm transmit flags - bitmap * @desc: command description used in the error message * * Return: * 0 when the operation is successful. * A negative number for system errors (errno). * A positive number for a TPM error. */ ssize_t tpm_transmit_cmd(struct tpm_chip *chip, struct tpm_space *space, void *buf, size_t bufsiz, size_t min_rsp_body_length, unsigned int flags, const char *desc) { const struct tpm_output_header *header = buf; int err; ssize_t len; len = tpm_transmit(chip, space, buf, bufsiz, flags); if (len < 0) return len; err = be32_to_cpu(header->return_code); if (err != 0 && err != TPM_ERR_DISABLED && err != TPM_ERR_DEACTIVATED && desc) dev_err(&chip->dev, "A TPM error (%d) occurred %s\n", err, desc); if (err) return err; if (len < min_rsp_body_length + TPM_HEADER_SIZE) return -EFAULT; return 0; } EXPORT_SYMBOL_GPL(tpm_transmit_cmd); int tpm_get_timeouts(struct tpm_chip *chip) { if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS) return 0; if (chip->flags & TPM_CHIP_FLAG_TPM2) return tpm2_get_timeouts(chip); else return tpm1_get_timeouts(chip); } EXPORT_SYMBOL_GPL(tpm_get_timeouts); /** * tpm_is_tpm2 - do we a have a TPM2 chip? * @chip: a &struct tpm_chip instance, %NULL for the default chip * * Return: * 1 if we have a TPM2 chip. * 0 if we don't have a TPM2 chip. * A negative number for system errors (errno). */ int tpm_is_tpm2(struct tpm_chip *chip) { int rc; chip = tpm_find_get_ops(chip); if (!chip) return -ENODEV; rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0; tpm_put_ops(chip); return rc; } EXPORT_SYMBOL_GPL(tpm_is_tpm2); /** * tpm_pcr_read - read a PCR value from SHA1 bank * @chip: a &struct tpm_chip instance, %NULL for the default chip * @pcr_idx: the PCR to be retrieved * @res_buf: the value of the PCR * * Return: same as with tpm_transmit_cmd() */ int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx, u8 *res_buf) { int rc; chip = tpm_find_get_ops(chip); if (!chip) return -ENODEV; if (chip->flags & TPM_CHIP_FLAG_TPM2) rc = tpm2_pcr_read(chip, pcr_idx, res_buf); else rc = tpm1_pcr_read(chip, pcr_idx, res_buf); tpm_put_ops(chip); return rc; } EXPORT_SYMBOL_GPL(tpm_pcr_read); /** * tpm_pcr_extend - extend a PCR value in SHA1 bank. * @chip: a &struct tpm_chip instance, %NULL for the default chip * @pcr_idx: the PCR to be retrieved * @hash: the hash value used to extend the PCR value * * Note: with TPM 2.0 extends also those banks with a known digest size to the * cryto subsystem in order to prevent malicious use of those PCR banks. In the * future we should dynamically determine digest sizes. * * Return: same as with tpm_transmit_cmd() */ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, const u8 *hash) { int rc; struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)]; u32 count = 0; int i; chip = tpm_find_get_ops(chip); if (!chip) return -ENODEV; if (chip->flags & TPM_CHIP_FLAG_TPM2) { memset(digest_list, 0, sizeof(digest_list)); for (i = 0; i < ARRAY_SIZE(chip->active_banks) && chip->active_banks[i] != TPM2_ALG_ERROR; i++) { digest_list[i].alg_id = chip->active_banks[i]; memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE); count++; } rc = tpm2_pcr_extend(chip, pcr_idx, count, digest_list); tpm_put_ops(chip); return rc; } rc = tpm1_pcr_extend(chip, pcr_idx, hash, "attempting extend a PCR value"); tpm_put_ops(chip); return rc; } EXPORT_SYMBOL_GPL(tpm_pcr_extend); /** * tpm_send - send a TPM command * @chip: a &struct tpm_chip instance, %NULL for the default chip * @cmd: a TPM command buffer * @buflen: the length of the TPM command buffer * * Return: same as with tpm_transmit_cmd() */ int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen) { int rc; chip = tpm_find_get_ops(chip); if (!chip) return -ENODEV; rc = tpm_transmit_cmd(chip, NULL, cmd, buflen, 0, 0, "attempting to a send a command"); tpm_put_ops(chip); return rc; } EXPORT_SYMBOL_GPL(tpm_send); int tpm_auto_startup(struct tpm_chip *chip) { int rc; if (!(chip->ops->flags & TPM_OPS_AUTO_STARTUP)) return 0; if (chip->flags & TPM_CHIP_FLAG_TPM2) rc = tpm2_auto_startup(chip); else rc = tpm1_auto_startup(chip); return rc; } /* * We are about to suspend. Save the TPM state * so that it can be restored. */ int tpm_pm_suspend(struct device *dev) { struct tpm_chip *chip = dev_get_drvdata(dev); int rc = 0; if (!chip) return -ENODEV; if (chip->flags & TPM_CHIP_FLAG_ALWAYS_POWERED) return 0; if (chip->flags & TPM_CHIP_FLAG_TPM2) tpm2_shutdown(chip, TPM2_SU_STATE); else rc = tpm1_pm_suspend(chip, tpm_suspend_pcr); return rc; } EXPORT_SYMBOL_GPL(tpm_pm_suspend); /* * Resume from a power safe. The BIOS already restored * the TPM state. */ int tpm_pm_resume(struct device *dev) { struct tpm_chip *chip = dev_get_drvdata(dev); if (chip == NULL) return -ENODEV; return 0; } EXPORT_SYMBOL_GPL(tpm_pm_resume); /** * tpm_get_random() - get random bytes from the TPM's RNG * @chip: a &struct tpm_chip instance, %NULL for the default chip * @out: destination buffer for the random bytes * @max: the max number of bytes to write to @out * * Return: number of random bytes read or a negative error value. */ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max) { int rc; if (!out || max > TPM_MAX_RNG_DATA) return -EINVAL; chip = tpm_find_get_ops(chip); if (!chip) return -ENODEV; if (chip->flags & TPM_CHIP_FLAG_TPM2) rc = tpm2_get_random(chip, out, max); else rc = tpm1_get_random(chip, out, max); tpm_put_ops(chip); return rc; } EXPORT_SYMBOL_GPL(tpm_get_random); /** * tpm_seal_trusted() - seal a trusted key payload * @chip: a &struct tpm_chip instance, %NULL for the default chip * @options: authentication values and other options * @payload: the key data in clear and encrypted form * * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in * the keyring subsystem. * * Return: same as with tpm_transmit_cmd() */ int tpm_seal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload, struct trusted_key_options *options) { int rc; chip = tpm_find_get_ops(chip); if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2)) return -ENODEV; rc = tpm2_seal_trusted(chip, payload, options); tpm_put_ops(chip); return rc; } EXPORT_SYMBOL_GPL(tpm_seal_trusted); /** * tpm_unseal_trusted() - unseal a trusted key * @chip: a &struct tpm_chip instance, %NULL for the default chip * @options: authentication values and other options * @payload: the key data in clear and encrypted form * * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in * the keyring subsystem. * * Return: same as with tpm_transmit_cmd() */ int tpm_unseal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload, struct trusted_key_options *options) { int rc; chip = tpm_find_get_ops(chip); if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2)) return -ENODEV; rc = tpm2_unseal_trusted(chip, payload, options); tpm_put_ops(chip); return rc; } EXPORT_SYMBOL_GPL(tpm_unseal_trusted); static int __init tpm_init(void) { int rc; tpm_class = class_create(THIS_MODULE, "tpm"); if (IS_ERR(tpm_class)) { pr_err("couldn't create tpm class\n"); return PTR_ERR(tpm_class); } tpmrm_class = class_create(THIS_MODULE, "tpmrm"); if (IS_ERR(tpmrm_class)) { pr_err("couldn't create tpmrm class\n"); rc = PTR_ERR(tpmrm_class); goto out_destroy_tpm_class; } rc = alloc_chrdev_region(&tpm_devt, 0, 2*TPM_NUM_DEVICES, "tpm"); if (rc < 0) { pr_err("tpm: failed to allocate char dev region\n"); goto out_destroy_tpmrm_class; } rc = tpm_dev_common_init(); if (rc) { pr_err("tpm: failed to allocate char dev region\n"); goto out_unreg_chrdev; } return 0; out_unreg_chrdev: unregister_chrdev_region(tpm_devt, 2 * TPM_NUM_DEVICES); out_destroy_tpmrm_class: class_destroy(tpmrm_class); out_destroy_tpm_class: class_destroy(tpm_class); return rc; } static void __exit tpm_exit(void) { idr_destroy(&dev_nums_idr); class_destroy(tpm_class); class_destroy(tpmrm_class); unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES); tpm_dev_common_exit(); } subsys_initcall(tpm_init); module_exit(tpm_exit); MODULE_AUTHOR("Leendert van Doorn (leendert@watson.ibm.com)"); MODULE_DESCRIPTION("TPM Driver"); MODULE_VERSION("2.0"); MODULE_LICENSE("GPL");