[qemu.git] / hw / tpm / tpm_util.c

/*
 * 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 "qemu/osdep.h"
#include "qemu/error-report.h"
#include "qapi/error.h"
#include "qapi/visitor.h"
#include "tpm_util.h"
#include "tpm_int.h"
#include "exec/memory.h"
#include "sysemu/tpm_backend.h"
#include "hw/qdev.h"

#define DEBUG_TPM 0

#define DPRINTF(fmt, ...) do { \
    if (DEBUG_TPM) { \
        fprintf(stderr, "tpm-util:"fmt"\n", ## __VA_ARGS__); \
    } \
} while (0)

/* tpm backend property */

static void get_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
                    Error **errp)
{
    DeviceState *dev = DEVICE(obj);
    TPMBackend **be = qdev_get_prop_ptr(dev, opaque);
    char *p;

    p = g_strdup(*be ? (*be)->id : "");
    visit_type_str(v, name, &p, errp);
    g_free(p);
}

static void set_tpm(Object *obj, Visitor *v, const char *name, void *opaque,
                    Error **errp)
{
    DeviceState *dev = DEVICE(obj);
    Error *local_err = NULL;
    Property *prop = opaque;
    TPMBackend *s, **be = qdev_get_prop_ptr(dev, prop);
    char *str;

    if (dev->realized) {
        qdev_prop_set_after_realize(dev, name, errp);
        return;
    }

    visit_type_str(v, name, &str, &local_err);
    if (local_err) {
        error_propagate(errp, local_err);
        return;
    }

    s = qemu_find_tpm_be(str);
    if (s == NULL) {
        error_setg(errp, "Property '%s.%s' can't find value '%s'",
                   object_get_typename(obj), prop->name, str);
    } else if (tpm_backend_init(s, TPM_IF(obj), errp) == 0) {
        *be = s; /* weak reference, avoid cyclic ref */
    }
    g_free(str);
}

static void release_tpm(Object *obj, const char *name, void *opaque)
{
    DeviceState *dev = DEVICE(obj);
    Property *prop = opaque;
    TPMBackend **be = qdev_get_prop_ptr(dev, prop);

    if (*be) {
        tpm_backend_reset(*be);
    }
}

const PropertyInfo qdev_prop_tpm = {
    .name  = "str",
    .description = "ID of a tpm to use as a backend",
    .get   = get_tpm,
    .set   = set_tpm,
    .release = release_tpm,
};

/*
 * Write an error message in the given output buffer.
 */
void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len)
{
    if (out_len >= sizeof(struct tpm_resp_hdr)) {
        tpm_cmd_set_tag(out, TPM_TAG_RSP_COMMAND);
        tpm_cmd_set_size(out, sizeof(struct tpm_resp_hdr));
        tpm_cmd_set_error(out, TPM_FAIL);
    }
}

bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len)
{
    if (in_len >= sizeof(struct tpm_req_hdr)) {
        return tpm_cmd_get_ordinal(in) == TPM_ORD_ContinueSelfTest;
    }

    return false;
}

/*
 * Send request to a TPM device. We expect a response within one second.
 */
static int tpm_util_request(int fd,
                            const void *request,
                            size_t requestlen,
                            void *response,
                            size_t responselen)
{
    fd_set readfds;
    int n;
    struct timeval tv = {
        .tv_sec = 1,
        .tv_usec = 0,
    };

    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, response, responselen);
    if (n < sizeof(struct tpm_resp_hdr)) {
        return -EFAULT;
    }

    /* check the header */
    if (tpm_cmd_get_size(response) != n) {
        return -EMSGSIZE;
    }

    return 0;
}

/*
 * A basic test of a TPM device. We expect a well formatted response header
 * (error response is fine).
 */
static int tpm_util_test(int fd,
                         const void *request,
                         size_t requestlen,
                         uint16_t *return_tag)
{
    char buf[1024];
    ssize_t ret;

    ret = tpm_util_request(fd, request, requestlen,
                           buf, sizeof(buf));
    if (ret < 0) {
        return ret;
    }

    *return_tag = tpm_cmd_get_tag(buf);

    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, &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, &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;
}

int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version,
                             size_t *buffersize)
{
    int ret;

    switch (tpm_version) {
    case TPM_VERSION_1_2: {
        const struct tpm_req_get_buffer_size {
            struct tpm_req_hdr hdr;
            uint32_t capability;
            uint32_t len;
            uint32_t subcap;
        } QEMU_PACKED tpm_get_buffer_size = {
            .hdr = {
                .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
                .len = cpu_to_be32(sizeof(tpm_get_buffer_size)),
                .ordinal = cpu_to_be32(TPM_ORD_GetCapability),
            },
            .capability = cpu_to_be32(TPM_CAP_PROPERTY),
            .len = cpu_to_be32(sizeof(uint32_t)),
            .subcap = cpu_to_be32(TPM_CAP_PROP_INPUT_BUFFER),
        };
        struct tpm_resp_get_buffer_size {
            struct tpm_resp_hdr hdr;
            uint32_t len;
            uint32_t buffersize;
        } QEMU_PACKED tpm_resp;

        ret = tpm_util_request(tpm_fd, &tpm_get_buffer_size,
                               sizeof(tpm_get_buffer_size),
                               &tpm_resp, sizeof(tpm_resp));
        if (ret < 0) {
            return ret;
        }

        if (be32_to_cpu(tpm_resp.hdr.len) != sizeof(tpm_resp) ||
            be32_to_cpu(tpm_resp.len) != sizeof(uint32_t)) {
            DPRINTF("tpm_resp->hdr.len = %u, expected = %zu\n",
                    be32_to_cpu(tpm_resp.hdr.len), sizeof(tpm_resp));
            DPRINTF("tpm_resp->len = %u, expected = %zu\n",
                    be32_to_cpu(tpm_resp.len), sizeof(uint32_t));
            error_report("tpm_util: Got unexpected response to "
                         "TPM_GetCapability; errcode: 0x%x",
                         be32_to_cpu(tpm_resp.hdr.errcode));
            return -EFAULT;
        }
        *buffersize = be32_to_cpu(tpm_resp.buffersize);
        break;
    }
    case TPM_VERSION_2_0: {
        const struct tpm2_req_get_buffer_size {
            struct tpm_req_hdr hdr;
            uint32_t capability;
            uint32_t property;
            uint32_t count;
        } QEMU_PACKED tpm2_get_buffer_size = {
            .hdr = {
                .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
                .len = cpu_to_be32(sizeof(tpm2_get_buffer_size)),
                .ordinal = cpu_to_be32(TPM2_CC_GetCapability),
            },
            .capability = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES),
            .property = cpu_to_be32(TPM2_PT_MAX_COMMAND_SIZE),
            .count = cpu_to_be32(2), /* also get TPM2_PT_MAX_RESPONSE_SIZE */
        };
        struct tpm2_resp_get_buffer_size {
            struct tpm_resp_hdr hdr;
            uint8_t more;
            uint32_t capability;
            uint32_t count;
            uint32_t property1;
            uint32_t value1;
            uint32_t property2;
            uint32_t value2;
        } QEMU_PACKED tpm2_resp;

        ret = tpm_util_request(tpm_fd, &tpm2_get_buffer_size,
                               sizeof(tpm2_get_buffer_size),
                               &tpm2_resp, sizeof(tpm2_resp));
        if (ret < 0) {
            return ret;
        }

        if (be32_to_cpu(tpm2_resp.hdr.len) != sizeof(tpm2_resp) ||
            be32_to_cpu(tpm2_resp.count) != 2) {
            DPRINTF("tpm2_resp->hdr.len = %u, expected = %zu\n",
                    be32_to_cpu(tpm2_resp.hdr.len), sizeof(tpm2_resp));
            DPRINTF("tpm2_resp->len = %u, expected = %u\n",
                    be32_to_cpu(tpm2_resp.count), 2);
            error_report("tpm_util: Got unexpected response to "
                         "TPM2_GetCapability; errcode: 0x%x",
                         be32_to_cpu(tpm2_resp.hdr.errcode));
            return -EFAULT;
        }
        *buffersize = MAX(be32_to_cpu(tpm2_resp.value1),
                          be32_to_cpu(tpm2_resp.value2));
        break;
    }
    case TPM_VERSION_UNSPEC:
        return -EFAULT;
    }

    DPRINTF("buffersize of device: %zu\n", *buffersize);

    return 0;
}

void tpm_sized_buffer_reset(TPMSizedBuffer *tsb)
{
    g_free(tsb->buffer);
    tsb->buffer = NULL;
    tsb->size = 0;
}
Commit	Line	Data
56a3c24f SB	1	/*
	2	* TPM utility functions
	3	*
	4	* Copyright (c) 2010 - 2015 IBM Corporation
	5	* Authors:
	6	* Stefan Berger <stefanb@us.ibm.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; either
	11	* version 2 of the License, or (at your option) any later version.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, see <http://www.gnu.org/licenses/>
	20	*/
	21
0430891c	22	#include "qemu/osdep.h"
abc5cda0	23	#include "qemu/error-report.h"
89be9e99 CH	24	#include "qapi/error.h"
89be9e99 CH	25	#include "qapi/visitor.h"
56a3c24f SB	26	#include "tpm_util.h"
56a3c24f SB	27	#include "tpm_int.h"
5086bf97	28	#include "exec/memory.h"
89be9e99 CH	29	#include "sysemu/tpm_backend.h"
89be9e99 CH	30	#include "hw/qdev.h"
56a3c24f	31
abc5cda0 SB	32	#define DEBUG_TPM 0
	33
	34	#define DPRINTF(fmt, ...) do { \
	35	if (DEBUG_TPM) { \
	36	fprintf(stderr, "tpm-util:"fmt"\n", ## __VA_ARGS__); \
	37	} \
	38	} while (0)
	39
89be9e99 CH	40	/* tpm backend property */
	41
	42	static void get_tpm(Object obj, Visitor v, const char name, void opaque,
	43	Error **errp)
	44	{
	45	DeviceState *dev = DEVICE(obj);
	46	TPMBackend **be = qdev_get_prop_ptr(dev, opaque);
	47	char *p;
	48
	49	p = g_strdup(be ? (be)->id : "");
	50	visit_type_str(v, name, &p, errp);
	51	g_free(p);
	52	}
	53
	54	static void set_tpm(Object obj, Visitor v, const char name, void opaque,
	55	Error **errp)
	56	{
	57	DeviceState *dev = DEVICE(obj);
	58	Error *local_err = NULL;
	59	Property *prop = opaque;
	60	TPMBackend s, *be = qdev_get_prop_ptr(dev, prop);
	61	char *str;
	62
	63	if (dev->realized) {
	64	qdev_prop_set_after_realize(dev, name, errp);
	65	return;
	66	}
	67
	68	visit_type_str(v, name, &str, &local_err);
	69	if (local_err) {
	70	error_propagate(errp, local_err);
	71	return;
	72	}
	73
	74	s = qemu_find_tpm_be(str);
	75	if (s == NULL) {
	76	error_setg(errp, "Property '%s.%s' can't find value '%s'",
	77	object_get_typename(obj), prop->name, str);
	78	} else if (tpm_backend_init(s, TPM_IF(obj), errp) == 0) {
	79	be = s; / weak reference, avoid cyclic ref */
	80	}
	81	g_free(str);
	82	}
	83
	84	static void release_tpm(Object obj, const char name, void *opaque)
	85	{
	86	DeviceState *dev = DEVICE(obj);
	87	Property *prop = opaque;
	88	TPMBackend **be = qdev_get_prop_ptr(dev, prop);
	89
	90	if (*be) {
	91	tpm_backend_reset(*be);
	92	}
	93	}
	94
	95	const PropertyInfo qdev_prop_tpm = {
	96	.name = "str",
	97	.description = "ID of a tpm to use as a backend",
	98	.get = get_tpm,
	99	.set = set_tpm,
	100	.release = release_tpm,
	101	};
	102
4a3d8098 AV	103	/*
	104	* Write an error message in the given output buffer.
	105	*/
	106	void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len)
	107	{
	108	if (out_len >= sizeof(struct tpm_resp_hdr)) {
a35e15dc SB	109	tpm_cmd_set_tag(out, TPM_TAG_RSP_COMMAND);
	110	tpm_cmd_set_size(out, sizeof(struct tpm_resp_hdr));
	111	tpm_cmd_set_error(out, TPM_FAIL);
4a3d8098 AV	112	}
	113	}
	114
	115	bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len)
	116	{
cc1b6c55 MAL	117	if (in_len >= sizeof(struct tpm_req_hdr)) {
cc1b6c55 MAL	118	return tpm_cmd_get_ordinal(in) == TPM_ORD_ContinueSelfTest;
4a3d8098 AV	119	}
	120
	121	return false;
	122	}
	123
56a3c24f	124	/*
56388eee	125	* Send request to a TPM device. We expect a response within one second.
56a3c24f	126	*/
56388eee	127	static int tpm_util_request(int fd,
cc1b6c55	128	const void *request,
56388eee	129	size_t requestlen,
cc1b6c55	130	void *response,
56388eee	131	size_t responselen)
56a3c24f	132	{
56a3c24f SB	133	fd_set readfds;
	134	int n;
	135	struct timeval tv = {
	136	.tv_sec = 1,
	137	.tv_usec = 0,
	138	};
56a3c24f SB	139
	140	n = write(fd, request, requestlen);
	141	if (n < 0) {
98979cdc	142	return -errno;
56a3c24f SB	143	}
56a3c24f SB	144	if (n != requestlen) {
98979cdc	145	return -EFAULT;
56a3c24f SB	146	}
	147
	148	FD_ZERO(&readfds);
	149	FD_SET(fd, &readfds);
	150
	151	/* wait for a second */
	152	n = select(fd + 1, &readfds, NULL, NULL, &tv);
	153	if (n != 1) {
98979cdc	154	return -errno;
56a3c24f SB	155	}
56a3c24f SB	156
56388eee	157	n = read(fd, response, responselen);
56a3c24f	158	if (n < sizeof(struct tpm_resp_hdr)) {
98979cdc	159	return -EFAULT;
56a3c24f SB	160	}
56a3c24f SB	161
56a3c24f	162	/* check the header */
cc1b6c55	163	if (tpm_cmd_get_size(response) != n) {
98979cdc	164	return -EMSGSIZE;
56a3c24f SB	165	}
56a3c24f SB	166
56388eee SB	167	return 0;
	168	}
	169
	170	/*
	171	* A basic test of a TPM device. We expect a well formatted response header
	172	* (error response is fine).
	173	*/
	174	static int tpm_util_test(int fd,
cc1b6c55	175	const void *request,
56388eee SB	176	size_t requestlen,
	177	uint16_t *return_tag)
	178	{
cc1b6c55	179	char buf[1024];
56388eee SB	180	ssize_t ret;
	181
	182	ret = tpm_util_request(fd, request, requestlen,
	183	buf, sizeof(buf));
	184	if (ret < 0) {
	185	return ret;
	186	}
	187
cc1b6c55	188	*return_tag = tpm_cmd_get_tag(buf);
56a3c24f SB	189
	190	return 0;
	191	}
	192
	193	/*
	194	* Probe for the TPM device in the back
	195	* Returns 0 on success with the version of the probed TPM set, 1 on failure.
	196	*/
	197	int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version)
	198	{
	199	/*
	200	* Sending a TPM1.2 command to a TPM2 should return a TPM1.2
	201	* header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e)
	202	*
	203	* Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the
	204	* header.
	205	* Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag
	206	* in the header and an error code.
	207	*/
	208	const struct tpm_req_hdr test_req = {
	209	.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
	210	.len = cpu_to_be32(sizeof(test_req)),
	211	.ordinal = cpu_to_be32(TPM_ORD_GetTicks),
	212	};
	213
	214	const struct tpm_req_hdr test_req_tpm2 = {
	215	.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
	216	.len = cpu_to_be32(sizeof(test_req_tpm2)),
	217	.ordinal = cpu_to_be32(TPM2_CC_ReadClock),
	218	};
	219	uint16_t return_tag;
	220	int ret;
	221
	222	/* Send TPM 2 command */
cc1b6c55	223	ret = tpm_util_test(tpm_fd, &test_req_tpm2,
56a3c24f SB	224	sizeof(test_req_tpm2), &return_tag);
	225	/* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */
	226	if (!ret && return_tag == TPM2_ST_NO_SESSIONS) {
	227	*tpm_version = TPM_VERSION_2_0;
	228	return 0;
	229	}
	230
	231	/* Send TPM 1.2 command */
cc1b6c55	232	ret = tpm_util_test(tpm_fd, &test_req,
56a3c24f SB	233	sizeof(test_req), &return_tag);
	234	if (!ret && return_tag == TPM_TAG_RSP_COMMAND) {
	235	*tpm_version = TPM_VERSION_1_2;
	236	/* this is a TPM 1.2 */
	237	return 0;
	238	}
	239
	240	*tpm_version = TPM_VERSION_UNSPEC;
	241
	242	return 1;
	243	}
abc5cda0 SB	244
	245	int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version,
	246	size_t *buffersize)
	247	{
abc5cda0 SB	248	int ret;
	249
	250	switch (tpm_version) {
	251	case TPM_VERSION_1_2: {
	252	const struct tpm_req_get_buffer_size {
	253	struct tpm_req_hdr hdr;
	254	uint32_t capability;
	255	uint32_t len;
	256	uint32_t subcap;
	257	} QEMU_PACKED tpm_get_buffer_size = {
	258	.hdr = {
	259	.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
	260	.len = cpu_to_be32(sizeof(tpm_get_buffer_size)),
	261	.ordinal = cpu_to_be32(TPM_ORD_GetCapability),
	262	},
	263	.capability = cpu_to_be32(TPM_CAP_PROPERTY),
	264	.len = cpu_to_be32(sizeof(uint32_t)),
	265	.subcap = cpu_to_be32(TPM_CAP_PROP_INPUT_BUFFER),
	266	};
	267	struct tpm_resp_get_buffer_size {
	268	struct tpm_resp_hdr hdr;
	269	uint32_t len;
	270	uint32_t buffersize;
cc1b6c55	271	} QEMU_PACKED tpm_resp;
abc5cda0	272
cc1b6c55 MAL	273	ret = tpm_util_request(tpm_fd, &tpm_get_buffer_size,
	274	sizeof(tpm_get_buffer_size),
	275	&tpm_resp, sizeof(tpm_resp));
abc5cda0 SB	276	if (ret < 0) {
	277	return ret;
	278	}
	279
cc1b6c55 MAL	280	if (be32_to_cpu(tpm_resp.hdr.len) != sizeof(tpm_resp) \|\|
cc1b6c55 MAL	281	be32_to_cpu(tpm_resp.len) != sizeof(uint32_t)) {
abc5cda0	282	DPRINTF("tpm_resp->hdr.len = %u, expected = %zu\n",
cc1b6c55	283	be32_to_cpu(tpm_resp.hdr.len), sizeof(tpm_resp));
abc5cda0	284	DPRINTF("tpm_resp->len = %u, expected = %zu\n",
cc1b6c55	285	be32_to_cpu(tpm_resp.len), sizeof(uint32_t));
abc5cda0 SB	286	error_report("tpm_util: Got unexpected response to "
abc5cda0 SB	287	"TPM_GetCapability; errcode: 0x%x",
cc1b6c55	288	be32_to_cpu(tpm_resp.hdr.errcode));
abc5cda0 SB	289	return -EFAULT;
abc5cda0 SB	290	}
cc1b6c55	291	*buffersize = be32_to_cpu(tpm_resp.buffersize);
abc5cda0 SB	292	break;
	293	}
	294	case TPM_VERSION_2_0: {
	295	const struct tpm2_req_get_buffer_size {
	296	struct tpm_req_hdr hdr;
	297	uint32_t capability;
	298	uint32_t property;
	299	uint32_t count;
	300	} QEMU_PACKED tpm2_get_buffer_size = {
	301	.hdr = {
	302	.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
	303	.len = cpu_to_be32(sizeof(tpm2_get_buffer_size)),
	304	.ordinal = cpu_to_be32(TPM2_CC_GetCapability),
	305	},
	306	.capability = cpu_to_be32(TPM2_CAP_TPM_PROPERTIES),
	307	.property = cpu_to_be32(TPM2_PT_MAX_COMMAND_SIZE),
	308	.count = cpu_to_be32(2), /* also get TPM2_PT_MAX_RESPONSE_SIZE */
	309	};
	310	struct tpm2_resp_get_buffer_size {
	311	struct tpm_resp_hdr hdr;
	312	uint8_t more;
	313	uint32_t capability;
	314	uint32_t count;
	315	uint32_t property1;
	316	uint32_t value1;
	317	uint32_t property2;
	318	uint32_t value2;
cc1b6c55	319	} QEMU_PACKED tpm2_resp;
abc5cda0	320
cc1b6c55 MAL	321	ret = tpm_util_request(tpm_fd, &tpm2_get_buffer_size,
	322	sizeof(tpm2_get_buffer_size),
	323	&tpm2_resp, sizeof(tpm2_resp));
abc5cda0 SB	324	if (ret < 0) {
	325	return ret;
	326	}
	327
cc1b6c55 MAL	328	if (be32_to_cpu(tpm2_resp.hdr.len) != sizeof(tpm2_resp) \|\|
cc1b6c55 MAL	329	be32_to_cpu(tpm2_resp.count) != 2) {
abc5cda0	330	DPRINTF("tpm2_resp->hdr.len = %u, expected = %zu\n",
cc1b6c55	331	be32_to_cpu(tpm2_resp.hdr.len), sizeof(tpm2_resp));
abc5cda0	332	DPRINTF("tpm2_resp->len = %u, expected = %u\n",
cc1b6c55	333	be32_to_cpu(tpm2_resp.count), 2);
abc5cda0 SB	334	error_report("tpm_util: Got unexpected response to "
abc5cda0 SB	335	"TPM2_GetCapability; errcode: 0x%x",
cc1b6c55	336	be32_to_cpu(tpm2_resp.hdr.errcode));
abc5cda0 SB	337	return -EFAULT;
abc5cda0 SB	338	}
cc1b6c55 MAL	339	*buffersize = MAX(be32_to_cpu(tpm2_resp.value1),
cc1b6c55 MAL	340	be32_to_cpu(tpm2_resp.value2));
abc5cda0 SB	341	break;
	342	}
	343	case TPM_VERSION_UNSPEC:
	344	return -EFAULT;
	345	}
	346
	347	DPRINTF("buffersize of device: %zu\n", *buffersize);
	348
	349	return 0;
	350	}
b86da7dd SB	351
	352	void tpm_sized_buffer_reset(TPMSizedBuffer *tsb)
	353	{
	354	g_free(tsb->buffer);
	355	tsb->buffer = NULL;
	356	tsb->size = 0;
	357	}