tcti/tcti.h

/***********************************************************************
 * Copyright (c) 2015 - 2018 Intel Corporation
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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/*
 * The context for TCTI implementations is on opaque
 * structure. There shall never be a definition of its content.
 * Implementation provide the size information to
 * applications via the initialize call.
 * This makes use of a compiler trick that allows type
 * checking of the pointer even though the type isn't
 * defined.
 *
 * The first field of a Context must be the common part
 * (see below).
 */
#ifndef TSS2_TCTI_UTIL_H
#define TSS2_TCTI_UTIL_H

#include <errno.h>
#include <stdbool.h>

#if defined(__linux__) || defined(__unix__) || defined(__APPLE__)
#include <sys/socket.h>
#define SOCKET int
#endif

#include "tpm20.h"

#define TCTI_MAGIC   0x7e18e9defa8bc9e2ULL
#define TCTI_VERSION 0x2

#define TCTI_CONTEXT ((TSS2_TCTI_CONTEXT_COMMON_CURRENT *)(SYS_CONTEXT->tctiContext))

#define TPM_HEADER_SIZE (sizeof (TPM2_ST) + sizeof (UINT32) + sizeof (UINT32))

#define TEMP_RETRY(exp) \
({  int __ret; \
    do { \
        __ret = exp; \
    } while (__ret == -1 && errno == EINTR); \
    __ret; })

typedef struct {
    TPM2_ST tag;
    UINT32 size;
    UINT32 code;
} tpm_header_t;
/*
 * The elements in this enumeration represent the possible states that the
 * TCTI can be in. The state machine is as follows:
 * An instantiated TCTI context begins in the TRANSMIT state:
 *   TRANSMIT:
 *     transmit:    success transitions the state machine to RECEIVE
 *                  failure leaves the state unchanged
 *     receive:     produces TSS2_TCTI_RC_BAD_SEQUENCE
 *     finalize:    transitions state machine to FINAL state
 *     cancel:      produces TSS2_TCTI_RC_BAD_SEQUENCE
 *     setLocality: success or failure leaves state unchanged
 *   RECEIVE:
 *     transmit:    produces TSS2_TCTI_RC_BAD_SEQUENCE
 *     receive:     success transitions the state machine to TRANSMIT
 *                  failure with the following RCs leave the state unchanged:
 *                    TRY_AGAIN, INSUFFICIENT_BUFFER, BAD_CONTEXT,
 *                    BAD_REFERENCE, BAD_VALUE, BAD_SEQUENCE
 *                  all other failures transition state machine to
 *                    TRANSMIT (not recoverable)
 *     finalize:    transitions state machine to FINAL state
 *     cancel:      success transitions state machine to TRANSMIT
 *                  failure leaves state unchanged
 *     setLocality: produces TSS2_TCTI_RC_BAD_SEQUENCE
 *   FINAL:
 *     all function calls produce TSS2_TCTI_RC_BAD_SEQUENCE
 */
typedef enum {
    TCTI_STATE_FINAL,
    TCTI_STATE_TRANSMIT,
    TCTI_STATE_RECEIVE,
} tcti_state_t;

/* current Intel version */
typedef struct {
    TSS2_TCTI_CONTEXT_COMMON_V2 v2;
    tcti_state_t state;
    tpm_header_t header;
    uint8_t locality;

    /* Flag indicating if a command has been cancelled.
     * This is a temporary flag, which will be changed into
     * a tcti state when support for asynch operation will be added */
    bool cancel;

    /* Sockets if socket interface is being used. */
    SOCKET otherSock;
    SOCKET tpmSock;

    /* File descriptor for device file if real TPM is being used. */
    int devFile;
} TSS2_TCTI_CONTEXT_INTEL;

/*
 * This function is used to "up cast" the common TCTI interface type to the
 * private type used in the implementation. This is how we control access to
 * the data below the 'setLocality' function.
 */
static inline TSS2_TCTI_CONTEXT_INTEL*
tcti_context_intel_cast (TSS2_TCTI_CONTEXT *ctx)
{
    return (TSS2_TCTI_CONTEXT_INTEL*)ctx;
}
/*
 * This funciton performs common checks on the context structure. It should
 * be used by all externally facing TCTI functions before the context is used
 * as any of the private types.
 */
TSS2_RC
tcti_common_checks (
    TSS2_TCTI_CONTEXT *tcti_context);
/*
 * This function performs common checks on the context structure and the
 * buffer passed into TCTI 'transmit' functions.
 */
TSS2_RC
tcti_transmit_checks (
    TSS2_TCTI_CONTEXT *tctiContext,
    const uint8_t *command_buffer);
/*
 * This function performs common checks on the context structure, buffer and
 * size parameter passed to the TCTI 'receive' functions.
 */
TSS2_RC
tcti_receive_checks (
    TSS2_TCTI_CONTEXT *tctiContext,
    size_t            *response_size,
    unsigned char     *response_buffer);
/*
 * Just a function with the right prototype that returns the not implemented
 * RC for the TCTI layer.
 */
TSS2_RC
tcti_make_sticky_not_implemented (
    TSS2_TCTI_CONTEXT *tctiContext,
    TPM2_HANDLE *handle,
    uint8_t sticky);
/*
 * Read 'size' bytes from file descriptor 'fd' into buffer 'buf'. Additionally
 * this function will retry calls to the 'read' function when temporary errors
 * are detected. This is currently limited to interrupted system calls and
 * short reads.
 */
ssize_t
read_all (
    int fd,
    uint8_t *data,
    size_t size);
/*
 * Write 'size' bytes from 'buf' to file descriptor 'fd'. Additionally this
 * function will retry calls to the 'write' function when recoverable errors
 * are detected. This is currently limited to interrupted system calls and
 * short writes.
 */
ssize_t write_all (
    int fd,
    const uint8_t *buf,
    size_t size);
/*
 * Utility to function to parse the first 10 bytes of a buffer and populate
 * the 'header' structure with the results. The provided buffer is assumed to
 * be at least 10 bytes long.
 */
TSS2_RC
parse_header (
    const uint8_t *buf,
    tpm_header_t *header);

#endif