diff options
Diffstat (limited to 'drivers/char/tpm/tpm-interface.c')
| -rw-r--r-- | drivers/char/tpm/tpm-interface.c | 1056 |
1 files changed, 1056 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c new file mode 100644 index 000000000..e85d3416d --- /dev/null +++ b/drivers/char/tpm/tpm-interface.c @@ -0,0 +1,1056 @@ +/* + * Copyright (C) 2004 IBM Corporation + * Copyright (C) 2014 Intel Corporation + * + * Authors: + * Leendert van Doorn <leendert@watson.ibm.com> + * Dave Safford <safford@watson.ibm.com> + * Reiner Sailer <sailer@watson.ibm.com> + * Kylene Hall <kjhall@us.ibm.com> + * + * Maintained by: <tpmdd-devel@lists.sourceforge.net> + * + * 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 <linux/poll.h> +#include <linux/slab.h> +#include <linux/mutex.h> +#include <linux/spinlock.h> +#include <linux/freezer.h> + +#include "tpm.h" +#include "tpm_eventlog.h" + +#define TPM_MAX_ORDINAL 243 +#define TSC_MAX_ORDINAL 12 +#define TPM_PROTECTED_COMMAND 0x00 +#define TPM_CONNECTION_COMMAND 0x40 + +/* + * 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 int 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 faciltate flush on suspend."); + +/* + * Array with one entry per ordinal defining the maximum amount + * of time the chip could take to return the result. The ordinal + * designation of short, medium or long is defined in a table in + * TCG Specification TPM Main Part 2 TPM Structures Section 17. The + * values of the SHORT, MEDIUM, and LONG durations are retrieved + * from the chip during initialization with a call to tpm_get_timeouts. + */ +static const u8 tpm_ordinal_duration[TPM_MAX_ORDINAL] = { + TPM_UNDEFINED, /* 0 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 5 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 10 */ + TPM_SHORT, + TPM_MEDIUM, + TPM_LONG, + TPM_LONG, + TPM_MEDIUM, /* 15 */ + TPM_SHORT, + TPM_SHORT, + TPM_MEDIUM, + TPM_LONG, + TPM_SHORT, /* 20 */ + TPM_SHORT, + TPM_MEDIUM, + TPM_MEDIUM, + TPM_MEDIUM, + TPM_SHORT, /* 25 */ + TPM_SHORT, + TPM_MEDIUM, + TPM_SHORT, + TPM_SHORT, + TPM_MEDIUM, /* 30 */ + TPM_LONG, + TPM_MEDIUM, + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, /* 35 */ + TPM_MEDIUM, + TPM_MEDIUM, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_MEDIUM, /* 40 */ + TPM_LONG, + TPM_MEDIUM, + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, /* 45 */ + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_LONG, + TPM_MEDIUM, /* 50 */ + TPM_MEDIUM, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 55 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_MEDIUM, /* 60 */ + TPM_MEDIUM, + TPM_MEDIUM, + TPM_SHORT, + TPM_SHORT, + TPM_MEDIUM, /* 65 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 70 */ + TPM_SHORT, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 75 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_LONG, /* 80 */ + TPM_UNDEFINED, + TPM_MEDIUM, + TPM_LONG, + TPM_SHORT, + TPM_UNDEFINED, /* 85 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 90 */ + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_UNDEFINED, /* 95 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_MEDIUM, /* 100 */ + TPM_SHORT, + TPM_SHORT, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 105 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 110 */ + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, /* 115 */ + TPM_SHORT, + TPM_SHORT, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_LONG, /* 120 */ + TPM_LONG, + TPM_MEDIUM, + TPM_UNDEFINED, + TPM_SHORT, + TPM_SHORT, /* 125 */ + TPM_SHORT, + TPM_LONG, + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, /* 130 */ + TPM_MEDIUM, + TPM_UNDEFINED, + TPM_SHORT, + TPM_MEDIUM, + TPM_UNDEFINED, /* 135 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 140 */ + TPM_SHORT, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 145 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 150 */ + TPM_MEDIUM, + TPM_MEDIUM, + TPM_SHORT, + TPM_SHORT, + TPM_UNDEFINED, /* 155 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 160 */ + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 165 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_LONG, /* 170 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 175 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_MEDIUM, /* 180 */ + TPM_SHORT, + TPM_MEDIUM, + TPM_MEDIUM, + TPM_MEDIUM, + TPM_MEDIUM, /* 185 */ + TPM_SHORT, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 190 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 195 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 200 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, + TPM_SHORT, /* 205 */ + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_MEDIUM, /* 210 */ + TPM_UNDEFINED, + TPM_MEDIUM, + TPM_MEDIUM, + TPM_MEDIUM, + TPM_UNDEFINED, /* 215 */ + TPM_MEDIUM, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, + TPM_SHORT, /* 220 */ + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_SHORT, + TPM_UNDEFINED, /* 225 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 230 */ + TPM_LONG, + TPM_MEDIUM, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, /* 235 */ + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_UNDEFINED, + TPM_SHORT, /* 240 */ + TPM_UNDEFINED, + TPM_MEDIUM, +}; + +/* + * Returns max number of jiffies to wait + */ +unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, + u32 ordinal) +{ + int duration_idx = TPM_UNDEFINED; + int duration = 0; + u8 category = (ordinal >> 24) & 0xFF; + + if ((category == TPM_PROTECTED_COMMAND && ordinal < TPM_MAX_ORDINAL) || + (category == TPM_CONNECTION_COMMAND && ordinal < TSC_MAX_ORDINAL)) + duration_idx = tpm_ordinal_duration[ordinal]; + + if (duration_idx != TPM_UNDEFINED) + duration = chip->vendor.duration[duration_idx]; + if (duration <= 0) + return 2 * 60 * HZ; + else + return duration; +} +EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration); + +/* + * Internal kernel interface to transmit TPM commands + */ +ssize_t tpm_transmit(struct tpm_chip *chip, const char *buf, + size_t bufsiz) +{ + ssize_t rc; + u32 count, ordinal; + unsigned long stop; + + 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->pdev, + "invalid count value %x %zx\n", count, bufsiz); + return -E2BIG; + } + + mutex_lock(&chip->tpm_mutex); + + rc = chip->ops->send(chip, (u8 *) buf, count); + if (rc < 0) { + dev_err(chip->pdev, + "tpm_transmit: tpm_send: error %zd\n", rc); + goto out; + } + + if (chip->vendor.irq) + goto out_recv; + + if (chip->flags & TPM_CHIP_FLAG_TPM2) + stop = jiffies + tpm2_calc_ordinal_duration(chip, ordinal); + else + 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->pdev, "Operation Canceled\n"); + rc = -ECANCELED; + goto out; + } + + msleep(TPM_TIMEOUT); /* CHECK */ + rmb(); + } while (time_before(jiffies, stop)); + + chip->ops->cancel(chip); + dev_err(chip->pdev, "Operation Timed out\n"); + rc = -ETIME; + goto out; + +out_recv: + rc = chip->ops->recv(chip, (u8 *) buf, bufsiz); + if (rc < 0) + dev_err(chip->pdev, + "tpm_transmit: tpm_recv: error %zd\n", rc); +out: + mutex_unlock(&chip->tpm_mutex); + return rc; +} + +#define TPM_DIGEST_SIZE 20 +#define TPM_RET_CODE_IDX 6 + +ssize_t tpm_transmit_cmd(struct tpm_chip *chip, void *cmd, + int len, const char *desc) +{ + struct tpm_output_header *header; + int err; + + len = tpm_transmit(chip, (u8 *) cmd, len); + if (len < 0) + return len; + else if (len < TPM_HEADER_SIZE) + return -EFAULT; + + header = cmd; + + err = be32_to_cpu(header->return_code); + if (err != 0 && desc) + dev_err(chip->pdev, "A TPM error (%d) occurred %s\n", err, + desc); + + return err; +} + +#define TPM_INTERNAL_RESULT_SIZE 200 +#define TPM_ORD_GET_CAP cpu_to_be32(101) +#define TPM_ORD_GET_RANDOM cpu_to_be32(70) + +static const struct tpm_input_header tpm_getcap_header = { + .tag = TPM_TAG_RQU_COMMAND, + .length = cpu_to_be32(22), + .ordinal = TPM_ORD_GET_CAP +}; + +ssize_t tpm_getcap(struct device *dev, __be32 subcap_id, cap_t *cap, + const char *desc) +{ + struct tpm_cmd_t tpm_cmd; + int rc; + struct tpm_chip *chip = dev_get_drvdata(dev); + + tpm_cmd.header.in = tpm_getcap_header; + if (subcap_id == CAP_VERSION_1_1 || subcap_id == CAP_VERSION_1_2) { + tpm_cmd.params.getcap_in.cap = subcap_id; + /*subcap field not necessary */ + tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(0); + tpm_cmd.header.in.length -= cpu_to_be32(sizeof(__be32)); + } else { + if (subcap_id == TPM_CAP_FLAG_PERM || + subcap_id == TPM_CAP_FLAG_VOL) + tpm_cmd.params.getcap_in.cap = TPM_CAP_FLAG; + else + tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP; + tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4); + tpm_cmd.params.getcap_in.subcap = subcap_id; + } + rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, desc); + if (!rc) + *cap = tpm_cmd.params.getcap_out.cap; + return rc; +} + +void tpm_gen_interrupt(struct tpm_chip *chip) +{ + struct tpm_cmd_t tpm_cmd; + ssize_t rc; + + tpm_cmd.header.in = tpm_getcap_header; + tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP; + tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4); + tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT; + + rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, + "attempting to determine the timeouts"); +} +EXPORT_SYMBOL_GPL(tpm_gen_interrupt); + +#define TPM_ORD_STARTUP cpu_to_be32(153) +#define TPM_ST_CLEAR cpu_to_be16(1) +#define TPM_ST_STATE cpu_to_be16(2) +#define TPM_ST_DEACTIVATED cpu_to_be16(3) +static const struct tpm_input_header tpm_startup_header = { + .tag = TPM_TAG_RQU_COMMAND, + .length = cpu_to_be32(12), + .ordinal = TPM_ORD_STARTUP +}; + +static int tpm_startup(struct tpm_chip *chip, __be16 startup_type) +{ + struct tpm_cmd_t start_cmd; + start_cmd.header.in = tpm_startup_header; + + start_cmd.params.startup_in.startup_type = startup_type; + return tpm_transmit_cmd(chip, &start_cmd, TPM_INTERNAL_RESULT_SIZE, + "attempting to start the TPM"); +} + +int tpm_get_timeouts(struct tpm_chip *chip) +{ + struct tpm_cmd_t tpm_cmd; + unsigned long new_timeout[4]; + unsigned long old_timeout[4]; + struct duration_t *duration_cap; + ssize_t rc; + + tpm_cmd.header.in = tpm_getcap_header; + tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP; + tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4); + tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT; + rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, NULL); + + if (rc == TPM_ERR_INVALID_POSTINIT) { + /* The TPM is not started, we are the first to talk to it. + Execute a startup command. */ + dev_info(chip->pdev, "Issuing TPM_STARTUP"); + if (tpm_startup(chip, TPM_ST_CLEAR)) + return rc; + + tpm_cmd.header.in = tpm_getcap_header; + tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP; + tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4); + tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT; + rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, + NULL); + } + if (rc) { + dev_err(chip->pdev, + "A TPM error (%zd) occurred attempting to determine the timeouts\n", + rc); + goto duration; + } + + if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 || + be32_to_cpu(tpm_cmd.header.out.length) + != sizeof(tpm_cmd.header.out) + sizeof(u32) + 4 * sizeof(u32)) + return -EINVAL; + + old_timeout[0] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.a); + old_timeout[1] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.b); + old_timeout[2] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.c); + old_timeout[3] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.d); + memcpy(new_timeout, old_timeout, sizeof(new_timeout)); + + /* + * Provide ability for vendor overrides of timeout values in case + * of misreporting. + */ + if (chip->ops->update_timeouts != NULL) + chip->vendor.timeout_adjusted = + chip->ops->update_timeouts(chip, new_timeout); + + if (!chip->vendor.timeout_adjusted) { + /* Don't overwrite default if value is 0 */ + if (new_timeout[0] != 0 && new_timeout[0] < 1000) { + int i; + + /* timeouts in msec rather usec */ + for (i = 0; i != ARRAY_SIZE(new_timeout); i++) + new_timeout[i] *= 1000; + chip->vendor.timeout_adjusted = true; + } + } + + /* Report adjusted timeouts */ + if (chip->vendor.timeout_adjusted) { + dev_info(chip->pdev, + HW_ERR "Adjusting reported timeouts: A %lu->%luus B %lu->%luus C %lu->%luus D %lu->%luus\n", + old_timeout[0], new_timeout[0], + old_timeout[1], new_timeout[1], + old_timeout[2], new_timeout[2], + old_timeout[3], new_timeout[3]); + } + + chip->vendor.timeout_a = usecs_to_jiffies(new_timeout[0]); + chip->vendor.timeout_b = usecs_to_jiffies(new_timeout[1]); + chip->vendor.timeout_c = usecs_to_jiffies(new_timeout[2]); + chip->vendor.timeout_d = usecs_to_jiffies(new_timeout[3]); + +duration: + tpm_cmd.header.in = tpm_getcap_header; + tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP; + tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4); + tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_DURATION; + + rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, + "attempting to determine the durations"); + if (rc) + return rc; + + if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 || + be32_to_cpu(tpm_cmd.header.out.length) + != sizeof(tpm_cmd.header.out) + sizeof(u32) + 3 * sizeof(u32)) + return -EINVAL; + + duration_cap = &tpm_cmd.params.getcap_out.cap.duration; + chip->vendor.duration[TPM_SHORT] = + usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_short)); + chip->vendor.duration[TPM_MEDIUM] = + usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_medium)); + chip->vendor.duration[TPM_LONG] = + usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_long)); + + /* The Broadcom BCM0102 chipset in a Dell Latitude D820 gets the above + * value wrong and apparently reports msecs rather than usecs. So we + * fix up the resulting too-small TPM_SHORT value to make things work. + * We also scale the TPM_MEDIUM and -_LONG values by 1000. + */ + if (chip->vendor.duration[TPM_SHORT] < (HZ / 100)) { + chip->vendor.duration[TPM_SHORT] = HZ; + chip->vendor.duration[TPM_MEDIUM] *= 1000; + chip->vendor.duration[TPM_LONG] *= 1000; + chip->vendor.duration_adjusted = true; + dev_info(chip->pdev, "Adjusting TPM timeout parameters."); + } + return 0; +} +EXPORT_SYMBOL_GPL(tpm_get_timeouts); + +#define TPM_ORD_CONTINUE_SELFTEST 83 +#define CONTINUE_SELFTEST_RESULT_SIZE 10 + +static struct tpm_input_header continue_selftest_header = { + .tag = TPM_TAG_RQU_COMMAND, + .length = cpu_to_be32(10), + .ordinal = cpu_to_be32(TPM_ORD_CONTINUE_SELFTEST), +}; + +/** + * tpm_continue_selftest -- run TPM's selftest + * @chip: TPM chip to use + * + * Returns 0 on success, < 0 in case of fatal error or a value > 0 representing + * a TPM error code. + */ +static int tpm_continue_selftest(struct tpm_chip *chip) +{ + int rc; + struct tpm_cmd_t cmd; + + cmd.header.in = continue_selftest_header; + rc = tpm_transmit_cmd(chip, &cmd, CONTINUE_SELFTEST_RESULT_SIZE, + "continue selftest"); + return rc; +} + +#define TPM_ORDINAL_PCRREAD cpu_to_be32(21) +#define READ_PCR_RESULT_SIZE 30 +static struct tpm_input_header pcrread_header = { + .tag = TPM_TAG_RQU_COMMAND, + .length = cpu_to_be32(14), + .ordinal = TPM_ORDINAL_PCRREAD +}; + +int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf) +{ + int rc; + struct tpm_cmd_t cmd; + + cmd.header.in = pcrread_header; + cmd.params.pcrread_in.pcr_idx = cpu_to_be32(pcr_idx); + rc = tpm_transmit_cmd(chip, &cmd, READ_PCR_RESULT_SIZE, + "attempting to read a pcr value"); + + if (rc == 0) + memcpy(res_buf, cmd.params.pcrread_out.pcr_result, + TPM_DIGEST_SIZE); + return rc; +} + +/** + * tpm_pcr_read - read a pcr value + * @chip_num: tpm idx # or ANY + * @pcr_idx: pcr idx to retrieve + * @res_buf: TPM_PCR value + * size of res_buf is 20 bytes (or NULL if you don't care) + * + * The TPM driver should be built-in, but for whatever reason it + * isn't, protect against the chip disappearing, by incrementing + * the module usage count. + */ +int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf) +{ + struct tpm_chip *chip; + int rc; + + chip = tpm_chip_find_get(chip_num); + if (chip == NULL) + return -ENODEV; + if (chip->flags & TPM_CHIP_FLAG_TPM2) + rc = tpm2_pcr_read(chip, pcr_idx, res_buf); + else + rc = tpm_pcr_read_dev(chip, pcr_idx, res_buf); + tpm_chip_put(chip); + return rc; +} +EXPORT_SYMBOL_GPL(tpm_pcr_read); + +/** + * tpm_pcr_extend - extend pcr value with hash + * @chip_num: tpm idx # or AN& + * @pcr_idx: pcr idx to extend + * @hash: hash value used to extend pcr value + * + * The TPM driver should be built-in, but for whatever reason it + * isn't, protect against the chip disappearing, by incrementing + * the module usage count. + */ +#define TPM_ORD_PCR_EXTEND cpu_to_be32(20) +#define EXTEND_PCR_RESULT_SIZE 34 +static struct tpm_input_header pcrextend_header = { + .tag = TPM_TAG_RQU_COMMAND, + .length = cpu_to_be32(34), + .ordinal = TPM_ORD_PCR_EXTEND +}; + +int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash) +{ + struct tpm_cmd_t cmd; + int rc; + struct tpm_chip *chip; + + chip = tpm_chip_find_get(chip_num); + if (chip == NULL) + return -ENODEV; + + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + rc = tpm2_pcr_extend(chip, pcr_idx, hash); + tpm_chip_put(chip); + return rc; + } + + cmd.header.in = pcrextend_header; + cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(pcr_idx); + memcpy(cmd.params.pcrextend_in.hash, hash, TPM_DIGEST_SIZE); + rc = tpm_transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE, + "attempting extend a PCR value"); + + tpm_chip_put(chip); + return rc; +} +EXPORT_SYMBOL_GPL(tpm_pcr_extend); + +/** + * tpm_do_selftest - have the TPM continue its selftest and wait until it + * can receive further commands + * @chip: TPM chip to use + * + * Returns 0 on success, < 0 in case of fatal error or a value > 0 representing + * a TPM error code. + */ +int tpm_do_selftest(struct tpm_chip *chip) +{ + int rc; + unsigned int loops; + unsigned int delay_msec = 100; + unsigned long duration; + struct tpm_cmd_t cmd; + + duration = tpm_calc_ordinal_duration(chip, TPM_ORD_CONTINUE_SELFTEST); + + loops = jiffies_to_msecs(duration) / delay_msec; + + rc = tpm_continue_selftest(chip); + /* This may fail if there was no TPM driver during a suspend/resume + * cycle; some may return 10 (BAD_ORDINAL), others 28 (FAILEDSELFTEST) + */ + if (rc) + return rc; + + do { + /* Attempt to read a PCR value */ + cmd.header.in = pcrread_header; + cmd.params.pcrread_in.pcr_idx = cpu_to_be32(0); + rc = tpm_transmit(chip, (u8 *) &cmd, READ_PCR_RESULT_SIZE); + /* Some buggy TPMs will not respond to tpm_tis_ready() for + * around 300ms while the self test is ongoing, keep trying + * until the self test duration expires. */ + if (rc == -ETIME) { + dev_info(chip->pdev, HW_ERR "TPM command timed out during continue self test"); + msleep(delay_msec); + continue; + } + + if (rc < TPM_HEADER_SIZE) + return -EFAULT; + + rc = be32_to_cpu(cmd.header.out.return_code); + if (rc == TPM_ERR_DISABLED || rc == TPM_ERR_DEACTIVATED) { + dev_info(chip->pdev, + "TPM is disabled/deactivated (0x%X)\n", rc); + /* TPM is disabled and/or deactivated; driver can + * proceed and TPM does handle commands for + * suspend/resume correctly + */ + return 0; + } + if (rc != TPM_WARN_DOING_SELFTEST) + return rc; + msleep(delay_msec); + } while (--loops > 0); + + return rc; +} +EXPORT_SYMBOL_GPL(tpm_do_selftest); + +int tpm_send(u32 chip_num, void *cmd, size_t buflen) +{ + struct tpm_chip *chip; + int rc; + + chip = tpm_chip_find_get(chip_num); + if (chip == NULL) + return -ENODEV; + + rc = tpm_transmit_cmd(chip, cmd, buflen, "attempting tpm_cmd"); + + tpm_chip_put(chip); + return rc; +} +EXPORT_SYMBOL_GPL(tpm_send); + +static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask, + bool check_cancel, bool *canceled) +{ + u8 status = chip->ops->status(chip); + + *canceled = false; + if ((status & mask) == mask) + return true; + if (check_cancel && chip->ops->req_canceled(chip, status)) { + *canceled = true; + return true; + } + return false; +} + +int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout, + wait_queue_head_t *queue, bool check_cancel) +{ + unsigned long stop; + long rc; + u8 status; + bool canceled = false; + + /* check current status */ + status = chip->ops->status(chip); + if ((status & mask) == mask) + return 0; + + stop = jiffies + timeout; + + if (chip->vendor.irq) { +again: + timeout = stop - jiffies; + if ((long)timeout <= 0) + return -ETIME; + rc = wait_event_interruptible_timeout(*queue, + wait_for_tpm_stat_cond(chip, mask, check_cancel, + &canceled), + timeout); + if (rc > 0) { + if (canceled) + return -ECANCELED; + return 0; + } + if (rc == -ERESTARTSYS && freezing(current)) { + clear_thread_flag(TIF_SIGPENDING); + goto again; + } + } else { + do { + msleep(TPM_TIMEOUT); + status = chip->ops->status(chip); + if ((status & mask) == mask) + return 0; + } while (time_before(jiffies, stop)); + } + return -ETIME; +} +EXPORT_SYMBOL_GPL(wait_for_tpm_stat); + +#define TPM_ORD_SAVESTATE cpu_to_be32(152) +#define SAVESTATE_RESULT_SIZE 10 + +static struct tpm_input_header savestate_header = { + .tag = TPM_TAG_RQU_COMMAND, + .length = cpu_to_be32(10), + .ordinal = TPM_ORD_SAVESTATE +}; + +/* + * 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); + struct tpm_cmd_t cmd; + int rc, try; + + u8 dummy_hash[TPM_DIGEST_SIZE] = { 0 }; + + if (chip == NULL) + return -ENODEV; + + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + tpm2_shutdown(chip, TPM2_SU_STATE); + return 0; + } + + /* for buggy tpm, flush pcrs with extend to selected dummy */ + if (tpm_suspend_pcr) { + cmd.header.in = pcrextend_header; + cmd.params.pcrextend_in.pcr_idx = cpu_to_be32(tpm_suspend_pcr); + memcpy(cmd.params.pcrextend_in.hash, dummy_hash, + TPM_DIGEST_SIZE); + rc = tpm_transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE, + "extending dummy pcr before suspend"); + } + + /* now do the actual savestate */ + for (try = 0; try < TPM_RETRY; try++) { + cmd.header.in = savestate_header; + rc = tpm_transmit_cmd(chip, &cmd, SAVESTATE_RESULT_SIZE, NULL); + + /* + * If the TPM indicates that it is too busy to respond to + * this command then retry before giving up. It can take + * several seconds for this TPM to be ready. + * + * This can happen if the TPM has already been sent the + * SaveState command before the driver has loaded. TCG 1.2 + * specification states that any communication after SaveState + * may cause the TPM to invalidate previously saved state. + */ + if (rc != TPM_WARN_RETRY) + break; + msleep(TPM_TIMEOUT_RETRY); + } + + if (rc) + dev_err(chip->pdev, + "Error (%d) sending savestate before suspend\n", rc); + else if (try > 0) + dev_warn(chip->pdev, "TPM savestate took %dms\n", + try * TPM_TIMEOUT_RETRY); + + 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); + +#define TPM_GETRANDOM_RESULT_SIZE 18 +static struct tpm_input_header tpm_getrandom_header = { + .tag = TPM_TAG_RQU_COMMAND, + .length = cpu_to_be32(14), + .ordinal = TPM_ORD_GET_RANDOM +}; + +/** + * tpm_get_random() - Get random bytes from the tpm's RNG + * @chip_num: A specific chip number for the request or TPM_ANY_NUM + * @out: destination buffer for the random bytes + * @max: the max number of bytes to write to @out + * + * Returns < 0 on error and the number of bytes read on success + */ +int tpm_get_random(u32 chip_num, u8 *out, size_t max) +{ + struct tpm_chip *chip; + struct tpm_cmd_t tpm_cmd; + u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA); + int err, total = 0, retries = 5; + u8 *dest = out; + + if (!out || !num_bytes || max > TPM_MAX_RNG_DATA) + return -EINVAL; + + chip = tpm_chip_find_get(chip_num); + if (chip == NULL) + return -ENODEV; + + if (chip->flags & TPM_CHIP_FLAG_TPM2) { + err = tpm2_get_random(chip, out, max); + tpm_chip_put(chip); + return err; + } + + do { + tpm_cmd.header.in = tpm_getrandom_header; + tpm_cmd.params.getrandom_in.num_bytes = cpu_to_be32(num_bytes); + + err = tpm_transmit_cmd(chip, &tpm_cmd, + TPM_GETRANDOM_RESULT_SIZE + num_bytes, + "attempting get random"); + if (err) + break; + + recd = be32_to_cpu(tpm_cmd.params.getrandom_out.rng_data_len); + memcpy(dest, tpm_cmd.params.getrandom_out.rng_data, recd); + + dest += recd; + total += recd; + num_bytes -= recd; + } while (retries-- && total < max); + + tpm_chip_put(chip); + return total ? total : -EIO; +} +EXPORT_SYMBOL_GPL(tpm_get_random); + +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); + } + + rc = alloc_chrdev_region(&tpm_devt, 0, TPM_NUM_DEVICES, "tpm"); + if (rc < 0) { + pr_err("tpm: failed to allocate char dev region\n"); + class_destroy(tpm_class); + return rc; + } + + return 0; +} + +static void __exit tpm_exit(void) +{ + class_destroy(tpm_class); + unregister_chrdev_region(tpm_devt, TPM_NUM_DEVICES); +} + +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"); |