530 lines
12 KiB
C
530 lines
12 KiB
C
/*
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* Copyright (C) 2016 Intel Corporation
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*
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* Authors:
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* Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
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*
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* Maintained by: <tpmdd-devel@lists.sourceforge.net>
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*
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* This file contains TPM2 protocol implementations of the commands
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* used by the kernel internally.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*/
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#include <linux/gfp.h>
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#include <asm/unaligned.h>
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#include "tpm.h"
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enum tpm2_handle_types {
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TPM2_HT_HMAC_SESSION = 0x02000000,
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TPM2_HT_POLICY_SESSION = 0x03000000,
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TPM2_HT_TRANSIENT = 0x80000000,
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};
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struct tpm2_context {
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__be64 sequence;
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__be32 saved_handle;
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__be32 hierarchy;
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__be16 blob_size;
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} __packed;
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static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
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if (space->session_tbl[i])
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tpm2_flush_context_cmd(chip, space->session_tbl[i],
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TPM_TRANSMIT_NESTED);
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}
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}
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int tpm2_init_space(struct tpm_space *space)
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{
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space->context_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
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if (!space->context_buf)
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return -ENOMEM;
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space->session_buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
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if (space->session_buf == NULL) {
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kfree(space->context_buf);
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return -ENOMEM;
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}
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return 0;
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}
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void tpm2_del_space(struct tpm_chip *chip, struct tpm_space *space)
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{
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mutex_lock(&chip->tpm_mutex);
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tpm2_flush_sessions(chip, space);
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mutex_unlock(&chip->tpm_mutex);
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kfree(space->context_buf);
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kfree(space->session_buf);
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}
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static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
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unsigned int *offset, u32 *handle)
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{
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struct tpm_buf tbuf;
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struct tpm2_context *ctx;
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unsigned int body_size;
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int rc;
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rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_LOAD);
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if (rc)
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return rc;
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ctx = (struct tpm2_context *)&buf[*offset];
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body_size = sizeof(*ctx) + be16_to_cpu(ctx->blob_size);
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tpm_buf_append(&tbuf, &buf[*offset], body_size);
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rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 4,
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TPM_TRANSMIT_NESTED, NULL);
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if (rc < 0) {
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dev_warn(&chip->dev, "%s: failed with a system error %d\n",
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__func__, rc);
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tpm_buf_destroy(&tbuf);
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return -EFAULT;
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} else if (tpm2_rc_value(rc) == TPM2_RC_HANDLE ||
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rc == TPM2_RC_REFERENCE_H0) {
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/*
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* TPM_RC_HANDLE means that the session context can't
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* be loaded because of an internal counter mismatch
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* that makes the TPM think there might have been a
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* replay. This might happen if the context was saved
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* and loaded outside the space.
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*
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* TPM_RC_REFERENCE_H0 means the session has been
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* flushed outside the space
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*/
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*handle = 0;
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tpm_buf_destroy(&tbuf);
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return -ENOENT;
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} else if (rc > 0) {
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dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
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__func__, rc);
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tpm_buf_destroy(&tbuf);
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return -EFAULT;
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}
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*handle = be32_to_cpup((__be32 *)&tbuf.data[TPM_HEADER_SIZE]);
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*offset += body_size;
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tpm_buf_destroy(&tbuf);
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return 0;
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}
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static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
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unsigned int buf_size, unsigned int *offset)
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{
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struct tpm_buf tbuf;
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unsigned int body_size;
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int rc;
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rc = tpm_buf_init(&tbuf, TPM2_ST_NO_SESSIONS, TPM2_CC_CONTEXT_SAVE);
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if (rc)
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return rc;
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tpm_buf_append_u32(&tbuf, handle);
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rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 0,
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TPM_TRANSMIT_NESTED, NULL);
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if (rc < 0) {
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dev_warn(&chip->dev, "%s: failed with a system error %d\n",
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__func__, rc);
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tpm_buf_destroy(&tbuf);
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return -EFAULT;
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} else if (tpm2_rc_value(rc) == TPM2_RC_REFERENCE_H0) {
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tpm_buf_destroy(&tbuf);
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return -ENOENT;
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} else if (rc) {
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dev_warn(&chip->dev, "%s: failed with a TPM error 0x%04X\n",
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__func__, rc);
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tpm_buf_destroy(&tbuf);
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return -EFAULT;
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}
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body_size = tpm_buf_length(&tbuf) - TPM_HEADER_SIZE;
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if ((*offset + body_size) > buf_size) {
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dev_warn(&chip->dev, "%s: out of backing storage\n", __func__);
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tpm_buf_destroy(&tbuf);
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return -ENOMEM;
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}
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memcpy(&buf[*offset], &tbuf.data[TPM_HEADER_SIZE], body_size);
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*offset += body_size;
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tpm_buf_destroy(&tbuf);
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return 0;
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}
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static void tpm2_flush_space(struct tpm_chip *chip)
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{
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struct tpm_space *space = &chip->work_space;
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int i;
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for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++)
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if (space->context_tbl[i] && ~space->context_tbl[i])
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tpm2_flush_context_cmd(chip, space->context_tbl[i],
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TPM_TRANSMIT_NESTED);
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tpm2_flush_sessions(chip, space);
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}
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static int tpm2_load_space(struct tpm_chip *chip)
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{
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struct tpm_space *space = &chip->work_space;
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unsigned int offset;
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int i;
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int rc;
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for (i = 0, offset = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
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if (!space->context_tbl[i])
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continue;
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/* sanity check, should never happen */
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if (~space->context_tbl[i]) {
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dev_err(&chip->dev, "context table is inconsistent");
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return -EFAULT;
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}
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rc = tpm2_load_context(chip, space->context_buf, &offset,
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&space->context_tbl[i]);
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if (rc)
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return rc;
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}
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for (i = 0, offset = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
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u32 handle;
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if (!space->session_tbl[i])
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continue;
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rc = tpm2_load_context(chip, space->session_buf,
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&offset, &handle);
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if (rc == -ENOENT) {
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/* load failed, just forget session */
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space->session_tbl[i] = 0;
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} else if (rc) {
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tpm2_flush_space(chip);
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return rc;
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}
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if (handle != space->session_tbl[i]) {
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dev_warn(&chip->dev, "session restored to wrong handle\n");
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tpm2_flush_space(chip);
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return -EFAULT;
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}
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}
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return 0;
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}
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static bool tpm2_map_to_phandle(struct tpm_space *space, void *handle)
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{
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u32 vhandle = be32_to_cpup((__be32 *)handle);
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u32 phandle;
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int i;
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i = 0xFFFFFF - (vhandle & 0xFFFFFF);
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if (i >= ARRAY_SIZE(space->context_tbl) || !space->context_tbl[i])
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return false;
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phandle = space->context_tbl[i];
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*((__be32 *)handle) = cpu_to_be32(phandle);
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return true;
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}
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static int tpm2_map_command(struct tpm_chip *chip, u32 cc, u8 *cmd)
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{
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struct tpm_space *space = &chip->work_space;
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unsigned int nr_handles;
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u32 attrs;
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__be32 *handle;
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int i;
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i = tpm2_find_cc(chip, cc);
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if (i < 0)
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return -EINVAL;
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attrs = chip->cc_attrs_tbl[i];
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nr_handles = (attrs >> TPM2_CC_ATTR_CHANDLES) & GENMASK(2, 0);
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handle = (__be32 *)&cmd[TPM_HEADER_SIZE];
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for (i = 0; i < nr_handles; i++, handle++) {
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if ((be32_to_cpu(*handle) & 0xFF000000) == TPM2_HT_TRANSIENT) {
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if (!tpm2_map_to_phandle(space, handle))
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return -EINVAL;
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}
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}
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return 0;
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}
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int tpm2_prepare_space(struct tpm_chip *chip, struct tpm_space *space, u32 cc,
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u8 *cmd)
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{
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int rc;
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if (!space)
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return 0;
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memcpy(&chip->work_space.context_tbl, &space->context_tbl,
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sizeof(space->context_tbl));
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memcpy(&chip->work_space.session_tbl, &space->session_tbl,
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sizeof(space->session_tbl));
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memcpy(chip->work_space.context_buf, space->context_buf, PAGE_SIZE);
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memcpy(chip->work_space.session_buf, space->session_buf, PAGE_SIZE);
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rc = tpm2_load_space(chip);
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if (rc) {
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tpm2_flush_space(chip);
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return rc;
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}
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rc = tpm2_map_command(chip, cc, cmd);
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if (rc) {
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tpm2_flush_space(chip);
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return rc;
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}
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return 0;
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}
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static bool tpm2_add_session(struct tpm_chip *chip, u32 handle)
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{
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struct tpm_space *space = &chip->work_space;
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int i;
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for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++)
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if (space->session_tbl[i] == 0)
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break;
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if (i == ARRAY_SIZE(space->session_tbl))
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return false;
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space->session_tbl[i] = handle;
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return true;
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}
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static u32 tpm2_map_to_vhandle(struct tpm_space *space, u32 phandle, bool alloc)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
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if (alloc) {
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if (!space->context_tbl[i]) {
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space->context_tbl[i] = phandle;
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break;
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}
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} else if (space->context_tbl[i] == phandle)
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break;
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}
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if (i == ARRAY_SIZE(space->context_tbl))
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return 0;
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return TPM2_HT_TRANSIENT | (0xFFFFFF - i);
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}
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static int tpm2_map_response_header(struct tpm_chip *chip, u32 cc, u8 *rsp,
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size_t len)
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{
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struct tpm_space *space = &chip->work_space;
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struct tpm_output_header *header = (void *)rsp;
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u32 phandle;
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u32 phandle_type;
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u32 vhandle;
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u32 attrs;
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int i;
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if (be32_to_cpu(header->return_code) != TPM2_RC_SUCCESS)
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return 0;
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i = tpm2_find_cc(chip, cc);
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/* sanity check, should never happen */
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if (i < 0)
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return -EFAULT;
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attrs = chip->cc_attrs_tbl[i];
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if (!((attrs >> TPM2_CC_ATTR_RHANDLE) & 1))
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return 0;
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phandle = be32_to_cpup((__be32 *)&rsp[TPM_HEADER_SIZE]);
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phandle_type = phandle & 0xFF000000;
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switch (phandle_type) {
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case TPM2_HT_TRANSIENT:
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vhandle = tpm2_map_to_vhandle(space, phandle, true);
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if (!vhandle)
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goto out_no_slots;
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*(__be32 *)&rsp[TPM_HEADER_SIZE] = cpu_to_be32(vhandle);
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break;
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case TPM2_HT_HMAC_SESSION:
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case TPM2_HT_POLICY_SESSION:
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if (!tpm2_add_session(chip, phandle))
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goto out_no_slots;
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break;
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default:
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dev_err(&chip->dev, "%s: unknown handle 0x%08X\n",
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__func__, phandle);
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break;
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}
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return 0;
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out_no_slots:
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tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_NESTED);
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dev_warn(&chip->dev, "%s: out of slots for 0x%08X\n", __func__,
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phandle);
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return -ENOMEM;
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}
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struct tpm2_cap_handles {
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u8 more_data;
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__be32 capability;
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__be32 count;
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__be32 handles[];
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} __packed;
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static int tpm2_map_response_body(struct tpm_chip *chip, u32 cc, u8 *rsp,
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size_t len)
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{
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struct tpm_space *space = &chip->work_space;
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struct tpm_output_header *header = (void *)rsp;
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struct tpm2_cap_handles *data;
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u32 phandle;
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u32 phandle_type;
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u32 vhandle;
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int i;
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int j;
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if (cc != TPM2_CC_GET_CAPABILITY ||
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be32_to_cpu(header->return_code) != TPM2_RC_SUCCESS) {
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return 0;
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}
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if (len < TPM_HEADER_SIZE + 9)
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return -EFAULT;
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data = (void *)&rsp[TPM_HEADER_SIZE];
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if (be32_to_cpu(data->capability) != TPM2_CAP_HANDLES)
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return 0;
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if (len != TPM_HEADER_SIZE + 9 + 4 * be32_to_cpu(data->count))
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return -EFAULT;
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for (i = 0, j = 0; i < be32_to_cpu(data->count); i++) {
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phandle = be32_to_cpup((__be32 *)&data->handles[i]);
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phandle_type = phandle & 0xFF000000;
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switch (phandle_type) {
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case TPM2_HT_TRANSIENT:
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vhandle = tpm2_map_to_vhandle(space, phandle, false);
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if (!vhandle)
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break;
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data->handles[j] = cpu_to_be32(vhandle);
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j++;
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break;
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default:
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data->handles[j] = cpu_to_be32(phandle);
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j++;
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break;
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}
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}
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header->length = cpu_to_be32(TPM_HEADER_SIZE + 9 + 4 * j);
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data->count = cpu_to_be32(j);
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return 0;
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}
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static int tpm2_save_space(struct tpm_chip *chip)
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{
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struct tpm_space *space = &chip->work_space;
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unsigned int offset;
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int i;
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int rc;
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for (i = 0, offset = 0; i < ARRAY_SIZE(space->context_tbl); i++) {
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if (!(space->context_tbl[i] && ~space->context_tbl[i]))
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continue;
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rc = tpm2_save_context(chip, space->context_tbl[i],
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space->context_buf, PAGE_SIZE,
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&offset);
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if (rc == -ENOENT) {
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space->context_tbl[i] = 0;
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continue;
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} else if (rc)
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return rc;
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tpm2_flush_context_cmd(chip, space->context_tbl[i],
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TPM_TRANSMIT_NESTED);
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space->context_tbl[i] = ~0;
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}
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for (i = 0, offset = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
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if (!space->session_tbl[i])
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continue;
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rc = tpm2_save_context(chip, space->session_tbl[i],
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space->session_buf, PAGE_SIZE,
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&offset);
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if (rc == -ENOENT) {
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/* handle error saving session, just forget it */
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space->session_tbl[i] = 0;
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} else if (rc < 0) {
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tpm2_flush_space(chip);
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return rc;
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}
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}
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return 0;
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}
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int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
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u32 cc, u8 *buf, size_t *bufsiz)
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{
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struct tpm_output_header *header = (void *)buf;
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int rc;
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if (!space)
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return 0;
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rc = tpm2_map_response_header(chip, cc, buf, *bufsiz);
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if (rc) {
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tpm2_flush_space(chip);
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return rc;
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}
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rc = tpm2_map_response_body(chip, cc, buf, *bufsiz);
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if (rc) {
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tpm2_flush_space(chip);
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return rc;
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}
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rc = tpm2_save_space(chip);
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if (rc) {
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tpm2_flush_space(chip);
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return rc;
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}
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*bufsiz = be32_to_cpu(header->length);
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memcpy(&space->context_tbl, &chip->work_space.context_tbl,
|
|
sizeof(space->context_tbl));
|
|
memcpy(&space->session_tbl, &chip->work_space.session_tbl,
|
|
sizeof(space->session_tbl));
|
|
memcpy(space->context_buf, chip->work_space.context_buf, PAGE_SIZE);
|
|
memcpy(space->session_buf, chip->work_space.session_buf, PAGE_SIZE);
|
|
|
|
return 0;
|
|
}
|