tpm_tis.c

xen虚拟机源代码安装包

/*
 * tpm_tis.c - QEMU emulator for a 1.2 TPM with TIS interface
 *
 * Copyright (C) 2006 IBM Corporation
 *
 * Author: Stefan Berger <[e-mail]>
 *         David Safford <[e-mail]>
 *
 * 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.
 *
 *
 * Implementation of the TIS interface according to specs at
 * https://www.trustedcomputinggroup.org/groups/pc_client/TCG_PCClientTPMSpecification_1-20_1-00_FINAL.pdf
 *
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <fcntl.h>
#include <errno.h>
#include "vl.h"

//#define DEBUG_TPM

#define TPM_MAX_PKT	              4096

#define VTPM_BAD_INSTANCE             (uint32_t)0xffffffff

#define TIS_ADDR_BASE                 0xFED40000

/* tis registers */
#define TPM_REG_ACCESS                0x00
#define TPM_REG_INT_ENABLE            0x08
#define TPM_REG_INT_VECTOR            0x0c
#define TPM_REG_INT_STATUS            0x10
#define TPM_REG_INTF_CAPABILITY       0x14
#define TPM_REG_STS                   0x18
#define TPM_REG_DATA_FIFO             0x24
#define TPM_REG_DID_VID               0xf00
#define TPM_REG_RID                   0xf04

#define STS_VALID                    (1 << 7)
#define STS_COMMAND_READY            (1 << 6)
#define STS_TPM_GO                   (1 << 5)
#define STS_DATA_AVAILABLE           (1 << 4)
#define STS_EXPECT                   (1 << 3)
#define STS_RESPONSE_RETRY           (1 << 1)

#define ACCESS_TPM_REG_VALID_STS     (1 << 7)
#define ACCESS_ACTIVE_LOCALITY       (1 << 5)
#define ACCESS_BEEN_SEIZED           (1 << 4)
#define ACCESS_SEIZE                 (1 << 3)
#define ACCESS_PENDING_REQUEST       (1 << 2)
#define ACCESS_REQUEST_USE           (1 << 1)
#define ACCESS_TPM_ESTABLISHMENT     (1 << 0)

#define INT_ENABLED                  (1 << 31)
#define INT_DATA_AVAILABLE           (1 << 0)
#define INT_LOCALITY_CHANGED         (1 << 2)
#define INT_COMMAND_READY            (1 << 7)

#define INTERRUPTS_SUPPORTED         (INT_LOCALITY_CHANGED | \
                                      INT_DATA_AVAILABLE   | \
                                      INT_COMMAND_READY)
#define CAPABILITIES_SUPPORTED       ((1 << 4) |            \
                                      INTERRUPTS_SUPPORTED)

enum {
  STATE_IDLE = 0,
  STATE_READY,
  STATE_COMPLETION,
  STATE_EXECUTION,
  STATE_RECEPTION
};

#define NUM_LOCALITIES   5
#define NO_LOCALITY      0xff

#define IS_VALID_LOC(x) ((x) < NUM_LOCALITIES)

#define TPM_DID          0x0001
#define TPM_VID          0x0001
#define TPM_RID          0x0001

/* if the connection to the vTPM should be closed after a successfully
   received response; set to '0' to allow keeping the connection */
#define FORCE_CLOSE      0

/* local data structures */

typedef struct TPMTx {
    int fd[2];
} tpmTx;

typedef struct TPMBuffer {
    uint8_t instance[4];      /* instance number in network byte order */
    uint8_t buf[TPM_MAX_PKT];
} __attribute__((packed)) tpmBuffer;

/* locality data */
typedef struct TPMLocal {
    uint32_t state;
    uint8_t access;
    uint8_t sts;
    uint32_t inte;
    uint32_t ints;
} tpmLoc;

/* overall state of the TPM interface; 's' marks as save upon suspension */
typedef struct TPMState {
    uint32_t offset;            /* s */
    tpmBuffer buffer;           /* s */
    uint8_t active_loc;         /* s */
    uint8_t aborting_locty;
    uint8_t next_locty;
    uint8_t irq_pending;        /* s */
    tpmLoc loc[NUM_LOCALITIES]; /* s */
    QEMUTimer *poll_timer;
    SetIRQFunc *set_irq;
    void *irq_opaque;
    int irq;
    int poll_attempts;
    uint32_t vtpm_instance;  /* vtpm inst. number; determined from xenstore*/
    int Transmitlayer;
    tpmTx tpmTx;
} tpmState;


/* local prototypes */
static int TPM_Send(tpmState *s, tpmBuffer *buffer, uint8_t locty, char *msg);
static int TPM_Receive(tpmState *s, tpmBuffer *buffer);
static uint32_t vtpm_instance_from_xenstore(void);
static void tis_poll_timer(void *opaque);
static void tis_prep_next_interrupt(tpmState *s);
static void tis_raise_irq(tpmState *s, uint8_t locty, uint32_t irqmask);
static void close_vtpm_channel(tpmState *s, int force);
static void open_vtpm_channel(tpmState *s);
static void tis_attempt_receive(tpmState *s, uint8_t locty);

/* transport layer functions: local sockets */
static int create_local_socket(tpmState *s, uint32_t vtpm_instance);
static int write_local_socket(tpmState *s, const tpmBuffer *);
static int read_local_socket(tpmState *s, tpmBuffer *);
static int close_local_socket(tpmState *s, int force);
static int has_channel_local_socket(tpmState *s);
#define LOCAL_SOCKET_PATH     "/var/vtpm/socks/%d.socket" 


#define NUM_TRANSPORTS 1

struct vTPM_transmit {
    int (*open_fn) (tpmState *s, uint32_t vtpm_instance);
    int (*write_fn) (tpmState *s, const tpmBuffer *);
    int (*read_fn) (tpmState *s, tpmBuffer *);
    int (*close_fn) (tpmState *s, int);
    int (*has_channel) (tpmState *s);
} vTPMTransmit[NUM_TRANSPORTS] = {
    { .open_fn = create_local_socket,
      .write_fn = write_local_socket,
      .read_fn = read_local_socket,
      .close_fn = close_local_socket,
      .has_channel = has_channel_local_socket,
    }
};


#define IS_COMM_WITH_VTPM(s)                            \
     ((s)->Transmitlayer >= 0 &&                        \
      vTPMTransmit[(s)->Transmitlayer].has_channel(s))


/**********************************************************************
 helper functions
 *********************************************************************/

static inline uint32_t tpm_get_size_from_buffer(const uint8_t *buffer)
{
    uint32_t len = (buffer[4] << 8) + buffer[5];
    return len;
}

static inline void tpm_initialize_instance(tpmState *s, uint32_t instance)
{
    s->buffer.instance[0] = (instance >> 24) & 0xff;
    s->buffer.instance[1] = (instance >> 16) & 0xff;
    s->buffer.instance[2] = (instance >>  8) & 0xff;
    s->buffer.instance[3] = (instance >>  0) & 0xff;
}

/*
 * open communication channel with a vTPM
 */
static void open_vtpm_channel(tpmState *s)
{
    int idx;
    /* search a usable transmit layer */
    for (idx = 0; idx < NUM_TRANSPORTS; idx++) {
        if (1 == vTPMTransmit[idx].open_fn(s, s->vtpm_instance)) {
            /* found one */
            s->Transmitlayer = idx;
            break;
        }
    }
}

/*
 * close the communication channel with the vTPM
 */
static inline void close_vtpm_channel(tpmState *s, int force)
{
    if (1 == vTPMTransmit[s->Transmitlayer].close_fn(s, force)) {
        s->Transmitlayer = -1;
    }
}

static inline uint8_t locality_from_addr(target_phys_addr_t addr)
{
    return (uint8_t)((addr >> 12) & 0x7);
}


/**********************************************************************
    low-level transmission layer methods
 *********************************************************************/

/*
 * the 'open' method that creates the filedescriptor for communicating
 * only one is needed for reading and writing
 */
static int create_local_socket(tpmState *s, uint32_t vtpm_instance)
{
    int success = 1;
    if (s->tpmTx.fd[0] < 0) {
        s->tpmTx.fd[0] = socket(PF_LOCAL, SOCK_STREAM, 0);

#ifdef DEBUG_TPM
        fprintf(logfile," SOCKET FD %d errno %d \n",  s->tpmTx.fd[0], errno );
#endif
        if (has_channel_local_socket(s)) {
            int ret; 
            struct sockaddr_un addr;
            memset(&addr, 0x0, sizeof(addr));
            addr.sun_family = AF_LOCAL;
            snprintf(addr.sun_path, sizeof(addr.sun_path)-1,
		     LOCAL_SOCKET_PATH, (uint32_t) vtpm_instance);
#ifdef DEBUG_TPM
	    fprintf(logfile," SOCKET NAME %s \n",  addr.sun_path );
#endif

            if ((ret = connect(s->tpmTx.fd[0], (struct sockaddr *)&addr,
			       sizeof(addr))) != 0) {
                close_local_socket(s, 1);
#ifdef DEBUG_TPM
		fprintf(logfile," RET %d  errno %d\n", ret, errno );
#endif
                success = 0;
            } else {
                /* put filedescriptor in non-blocking mode for polling */
#ifdef DEBUG_TPM
	      fprintf(logfile," put filedescriptor in non-blocking mode "
		      "for polling \n");
#endif
                int flags = fcntl(s->tpmTx.fd[0], F_GETFL);
                fcntl(s->tpmTx.fd[0], F_SETFL, flags | O_NONBLOCK);
            }
#ifdef DEBUG_TPM
            if (success)
                fprintf(logfile," Successfully connected using local socket"
                                "%s.\n",addr.sun_path);
            else
                fprintf(logfile," Could not connect to local socket "
                                "%s.\n",addr.sun_path);
#endif
        } else {
            success = 0;
        }
    }
    return success;
}

/*
 * the 'write' method for sending requests to the vTPM
 * four bytes with the vTPM instance number are prepended to each request
 * the locality in which the command was sent is transmitted in the
 * highest 3 bits
 */
static int write_local_socket(tpmState *s, const tpmBuffer *buffer)
{
    uint32_t size = tpm_get_size_from_buffer(buffer->buf);
    int len;

    len = write(s->tpmTx.fd[0],
                buffer->instance,
                sizeof(buffer->instance) + size);
    if (len == sizeof(buffer->instance) + size) {
        return len;
    } else {
        return -1;
    }
}

/*
 * the 'read' method for receiving of responses from the TPM
 * this function expects that four bytes with the instance number
 * are received from the vTPM
 */
static int read_local_socket(tpmState *s, tpmBuffer *buffer)
{
    int off;
#ifdef DEBUG_TPM
    fprintf(logfile, "Reading from fd %d\n", s->tpmTx.fd[0]);
#endif
    off = read(s->tpmTx.fd[0],
               buffer->instance,
               sizeof(buffer->instance)+TPM_MAX_PKT);
#ifdef DEBUG_TPM
    fprintf(logfile, "Read %d bytes\n", off);
#endif
    return off;
}

/*
 * the 'close' method
 * shut down communication with the vTPM
 * 'force' = 1 indicates that the socket *must* be closed
 * 'force' = 0 indicates that a connection may be maintained
 */
static int close_local_socket(tpmState *s, int force)
{
    if (force) {
        close(s->tpmTx.fd[0]);
#ifdef DEBUG_TPM
        fprintf(logfile,"Closed connection with fd %d\n",s->tpmTx.fd[0]);
#endif
        s->tpmTx.fd[0] = -1;
        return 1; /* socket was closed */
    }
#ifdef DEBUG_TPM
    fprintf(logfile,"Keeping connection with fd %d\n",s->tpmTx.fd[0]);
#endif
    return 0;
}

/*
 * the 'has_channel' method that checks whether there's a communication
 * channel with the vTPM
 */
static int has_channel_local_socket(tpmState *s)
{
    return (s->tpmTx.fd[0] > 0);
}

/**********************************************************************/

/*
 * read a byte of response data
 */
static uint32_t tpm_data_read(tpmState *s, uint8_t locty)
{
    uint32_t ret, len;

    /* try to receive data, if none are there it is ok */
    tis_attempt_receive(s, locty);

    if (s->loc[locty].state != STATE_COMPLETION) {
        return 0xff;
    }

    len = tpm_get_size_from_buffer(s->buffer.buf);
    ret = s->buffer.buf[s->offset++];
    if (s->offset >= len) {
        s->loc[locty].sts = STS_VALID ;
        s->offset = 0;
    }
#ifdef DEBUG_TPM
    fprintf(logfile,"tpm_data_read byte x%02x   [%d]\n",ret,s->offset-1);
#endif
    return ret;
}