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tpm: tpm_passthrough: Read the buffer size from the host device

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Rather than hard coding the buffer size in the tpm_passthrough
backend read the TPM I/O buffer size from the host device.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
This commit is contained in:
Stefan Berger 2017-11-03 22:49:23 -04:00
parent 56388eee01
commit abc5cda097
4 changed files with 137 additions and 1 deletions
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9
hw/tpm/tpm_int.h
View File

@ -45,11 +45,20 @@ struct tpm_resp_hdr {
#define TPM_ORD_ContinueSelfTest 0x53
#define TPM_ORD_GetTicks 0xf1
#define TPM_ORD_GetCapability 0x65
#define TPM_CAP_PROPERTY 0x05
#define TPM_CAP_PROP_INPUT_BUFFER 0x124
/* TPM2 defines */
#define TPM2_ST_NO_SESSIONS 0x8001
#define TPM2_CC_ReadClock 0x00000181
#define TPM2_CC_GetCapability 0x0000017a
#define TPM2_CAP_TPM_PROPERTIES 0x6
#define TPM2_PT_MAX_COMMAND_SIZE 0x11e
#endif /* TPM_TPM_INT_H */

11
hw/tpm/tpm_passthrough.c
View File

@ -57,6 +57,7 @@ struct TPMPassthruState {
int cancel_fd;
TPMVersion tpm_version;
size_t tpm_buffersize;
};
typedef struct TPMPassthruState TPMPassthruState;
@ -201,7 +202,15 @@ static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
static size_t tpm_passthrough_get_buffer_size(TPMBackend *tb)
{
return 4096;
TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
int ret;
ret = tpm_util_get_buffer_size(tpm_pt->tpm_fd, tpm_pt->tpm_version,
&tpm_pt->tpm_buffersize);
if (ret < 0) {
tpm_pt->tpm_buffersize = 4096;
}
return tpm_pt->tpm_buffersize;
}
/*

115
hw/tpm/tpm_util.c
View File

@ -20,10 +20,19 @@
*/
#include "qemu/osdep.h"
#include "qemu/error-report.h"
#include "tpm_util.h"
#include "tpm_int.h"
#include "exec/memory.h"
#define DEBUG_TPM 0
#define DPRINTF(fmt, ...) do { \
if (DEBUG_TPM) { \
fprintf(stderr, "tpm-util:"fmt"\n", ## __VA_ARGS__); \
} \
} while (0)
/*
* Write an error message in the given output buffer.
*/
@ -173,3 +182,109 @@ int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version)
return 1;
}
int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version,
size_t *buffersize)
{
unsigned char buf[1024];
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 = (struct tpm_resp_get_buffer_size *)buf;
ret = tpm_util_request(tpm_fd, (unsigned char *)&tpm_get_buffer_size,
sizeof(tpm_get_buffer_size), buf, sizeof(buf));
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 = (struct tpm2_resp_get_buffer_size *)buf;
ret = tpm_util_request(tpm_fd, (unsigned char *)&tpm2_get_buffer_size,
sizeof(tpm2_get_buffer_size), buf, sizeof(buf));
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;
}

3
hw/tpm/tpm_util.h
View File

@ -36,4 +36,7 @@ static inline uint32_t tpm_cmd_get_size(const void *b)
return be32_to_cpu(*(const uint32_t *)(b + 2));
}
int tpm_util_get_buffer_size(int tpm_fd, TPMVersion tpm_version,
size_t *buffersize);
#endif /* TPM_TPM_UTIL_H */