Commit 56a3c24f authored by Stefan Berger's avatar Stefan Berger Committed by Michael S. Tsirkin
Browse files

tpm: Probe for connected TPM 1.2 or TPM 2 



In the TPM passthrough backend driver, modify the probing code so
that we can check whether a TPM 1.2 or TPM 2 is being used
and adapt the behavior of the TPM TIS accordingly.

Move the code that tested for a TPM 1.2 into tpm_utils.c
and extend it with test for probing for TPM 2. Have the
function return the version of TPM found.

Signed-off-by: default avatarStefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 116694c3

hw/tpm/Makefile.objs

+1 −1
Original line number Diff line number Diff line 
common-obj-$(CONFIG_TPM_TIS) += tpm_tis.o

common-obj-$(CONFIG_TPM_PASSTHROUGH) += tpm_passthrough.o
 
common-obj-$(CONFIG_TPM_PASSTHROUGH) += tpm_passthrough.o tpm_util.o

hw/tpm/tpm_int.h

+6 −0
Original line number Diff line number Diff line
@@ -66,4 +66,10 @@ struct tpm_resp_hdr { 
#define TPM_ORD_ContinueSelfTest  0x53

#define TPM_ORD_GetTicks          0xf1





/* TPM2 defines */

#define TPM2_ST_NO_SESSIONS       0x8001



#define TPM2_CC_ReadClock         0x00000181



#endif /* TPM_TPM_INT_H */

hw/tpm/tpm_passthrough.c

+6 −53
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ 
#include "hw/i386/pc.h"

#include "sysemu/tpm_backend_int.h"

#include "tpm_tis.h"

#include "tpm_util.h"



#define DEBUG_TPM 0
@@ -69,6 +70,8 @@ struct TPMPassthruState { 
    bool tpm_op_canceled;

    int cancel_fd;

    bool had_startup_error;



    TPMVersion tpm_version;

};



typedef struct TPMPassthruState TPMPassthruState;
@@ -333,59 +336,9 @@ static const char *tpm_passthrough_create_desc(void) 


static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)

{

    return TPM_VERSION_1_2;

}



/*

 * A basic test of a TPM device. We expect a well formatted response header

 * (error response is fine) within one second.

 */

static int tpm_passthrough_test_tpmdev(int fd)

{

    struct tpm_req_hdr req = {

        .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),

        .len = cpu_to_be32(sizeof(req)),

        .ordinal = cpu_to_be32(TPM_ORD_GetTicks),

    };

    struct tpm_resp_hdr *resp;

    fd_set readfds;

    int n;

    struct timeval tv = {

        .tv_sec = 1,

        .tv_usec = 0,

    };

    unsigned char buf[1024];



    n = write(fd, &req, sizeof(req));

    if (n < 0) {

        return errno;

    }

    if (n != sizeof(req)) {

        return EFAULT;

    }



    FD_ZERO(&readfds);

    FD_SET(fd, &readfds);



    /* wait for a second */

    n = select(fd + 1, &readfds, NULL, NULL, &tv);

    if (n != 1) {

        return errno;

    }



    n = read(fd, &buf, sizeof(buf));

    if (n < sizeof(struct tpm_resp_hdr)) {

        return EFAULT;

    }



    resp = (struct tpm_resp_hdr *)buf;

    /* check the header */

    if (be16_to_cpu(resp->tag) != TPM_TAG_RSP_COMMAND ||

        be32_to_cpu(resp->len) != n) {

        return EBADMSG;

    }

    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);



    return 0;

    return tpm_pt->tpm_version;

}



/*
@@ -455,7 +408,7 @@ static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb) 
        goto err_free_parameters;

    }



    if (tpm_passthrough_test_tpmdev(tpm_pt->tpm_fd)) {

    if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {

        error_report("'%s' is not a TPM device.",

                     tpm_pt->tpm_dev);

        goto err_close_tpmdev;

hw/tpm/tpm_util.c

0 → 100644
+126 −0
Original line number Diff line number Diff line 
/*

 * TPM utility functions

 *

 *  Copyright (c) 2010 - 2015 IBM Corporation

 *  Authors:

 *    Stefan Berger <stefanb@us.ibm.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>

 */



#include "tpm_util.h"

#include "tpm_int.h"



/*

 * A basic test of a TPM device. We expect a well formatted response header

 * (error response is fine) within one second.

 */

static int tpm_util_test(int fd,

                         unsigned char *request,

                         size_t requestlen,

                         uint16_t *return_tag)

{

    struct tpm_resp_hdr *resp;

    fd_set readfds;

    int n;

    struct timeval tv = {

        .tv_sec = 1,

        .tv_usec = 0,

    };

    unsigned char buf[1024];



    n = write(fd, request, requestlen);

    if (n < 0) {

        return errno;

    }

    if (n != requestlen) {

        return EFAULT;

    }



    FD_ZERO(&readfds);

    FD_SET(fd, &readfds);



    /* wait for a second */

    n = select(fd + 1, &readfds, NULL, NULL, &tv);

    if (n != 1) {

        return errno;

    }



    n = read(fd, &buf, sizeof(buf));

    if (n < sizeof(struct tpm_resp_hdr)) {

        return EFAULT;

    }



    resp = (struct tpm_resp_hdr *)buf;

    /* check the header */

    if (be32_to_cpu(resp->len) != n) {

        return EBADMSG;

    }



    *return_tag = be16_to_cpu(resp->tag);



    return 0;

}



/*

 * Probe for the TPM device in the back

 * Returns 0 on success with the version of the probed TPM set, 1 on failure.

 */

int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version)

{

    /*

     * Sending a TPM1.2 command to a TPM2 should return a TPM1.2

     * header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e)

     *

     * Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the

     * header.

     * Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag

     * in the header and an error code.

     */

    const struct tpm_req_hdr test_req = {

        .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),

        .len = cpu_to_be32(sizeof(test_req)),

        .ordinal = cpu_to_be32(TPM_ORD_GetTicks),

    };



    const struct tpm_req_hdr test_req_tpm2 = {

        .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),

        .len = cpu_to_be32(sizeof(test_req_tpm2)),

        .ordinal = cpu_to_be32(TPM2_CC_ReadClock),

    };

    uint16_t return_tag;

    int ret;



    /* Send TPM 2 command */

    ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req_tpm2,

                        sizeof(test_req_tpm2), &return_tag);

    /* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */

    if (!ret && return_tag == TPM2_ST_NO_SESSIONS) {

        *tpm_version = TPM_VERSION_2_0;

        return 0;

    }



    /* Send TPM 1.2 command */

    ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req,

                        sizeof(test_req), &return_tag);

    if (!ret && return_tag == TPM_TAG_RSP_COMMAND) {

        *tpm_version = TPM_VERSION_1_2;

        /* this is a TPM 1.2 */

        return 0;

    }



    *tpm_version = TPM_VERSION_UNSPEC;



    return 1;

}

hw/tpm/tpm_util.h

0 → 100644
+28 −0
Original line number Diff line number Diff line 
/*

 * TPM utility functions

 *

 *  Copyright (c) 2010 - 2015 IBM Corporation

 *  Authors:

 *    Stefan Berger <stefanb@us.ibm.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>

 */

#ifndef TPM_TPM_UTILS_H

#define TPM_TPM_UTILS_H



#include "sysemu/tpm_backend.h"



int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version);



#endif /* TPM_TPM_UTILS_H */