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Re: [Qemu-devel] [PATCH 3/5] tpm: tpm_passthrough: Read the buffer size
From: |
Marc-André Lureau |
Subject: |
Re: [Qemu-devel] [PATCH 3/5] tpm: tpm_passthrough: Read the buffer size from the host device |
Date: |
Wed, 8 Nov 2017 17:18:08 +0100 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
Hi Stefan,
On Mon, Nov 06, 2017 at 07:58:54PM -0500, Stefan Berger wrote:
> 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 <address@hidden>
> ---
> hw/tpm/tpm_int.h | 9 ++++
> hw/tpm/tpm_passthrough.c | 11 ++++-
> hw/tpm/tpm_util.c | 116
> +++++++++++++++++++++++++++++++++++++++++++++++
> hw/tpm/tpm_util.h | 3 ++
> 4 files changed, 138 insertions(+), 1 deletion(-)
>
> diff --git a/hw/tpm/tpm_int.h b/hw/tpm/tpm_int.h
> index 1df5883..f838535 100644
> --- a/hw/tpm/tpm_int.h
> +++ b/hw/tpm/tpm_int.h
> @@ -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_INPUT_BUFFER 0x10d
>
> #endif /* TPM_TPM_INT_H */
> diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
> index 7ff9249..ec755fe 100644
> --- a/hw/tpm/tpm_passthrough.c
> +++ b/hw/tpm/tpm_passthrough.c
> @@ -57,6 +57,7 @@ struct TPMPassthruState {
> int cancel_fd;
>
> TPMVersion tpm_version;
> + uint32_t tpm_buffersize;
> };
>
> typedef struct TPMPassthruState TPMPassthruState;
> @@ -201,7 +202,15 @@ static TPMVersion
> tpm_passthrough_get_tpm_version(TPMBackend *tb)
>
> static uint32_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;
> }
>
> /*
> diff --git a/hw/tpm/tpm_util.c b/hw/tpm/tpm_util.c
> index 396e793..3c861ab 100644
> --- a/hw/tpm/tpm_util.c
> +++ b/hw/tpm/tpm_util.c
> @@ -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.
> */
> @@ -170,3 +179,110 @@ 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,
> + uint32_t *buffersize)
> +{
> + unsigned char buf[1024];
> + 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),
> + };
> + 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_INPUT_BUFFER),
> + .count = cpu_to_be32(1),
> + };
> + 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;
> + struct tpm2_resp_get_buffer_size {
> + struct tpm_resp_hdr hdr;
> + uint8_t more;
> + uint32_t capability;
> + uint32_t count;
> + uint32_t property;
> + uint32_t value;
> + } QEMU_PACKED *tpm2_resp = (struct tpm2_resp_get_buffer_size *)buf;
> + unsigned char *request = NULL;
> + size_t requestlen;
> + int ret;
> +
> + switch (tpm_version) {
It may be more readable to split the function in 2 halfs, v1 & v2 versions.
> + case TPM_VERSION_1_2:
> + request = (unsigned char *)&tpm_get_buffer_size;
> + requestlen = sizeof(tpm_get_buffer_size);
> + break;
> + case TPM_VERSION_2_0:
> + request = (unsigned char *)&tpm2_get_buffer_size;
> + requestlen = sizeof(tpm2_get_buffer_size);
> + break;
> + case TPM_VERSION_UNSPEC:
> + return -EFAULT;
> + }
> +
> + ret = tpm_util_tx(tpm_fd, request, requestlen, buf, sizeof(buf));
> + if (ret < 0) {
> + return ret;
> + }
> +
> + switch (tpm_version) {
> + case TPM_VERSION_1_2:
> + 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 malformed 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:
> + if (be32_to_cpu(tpm2_resp->hdr.len) != sizeof(*tpm2_resp) ||
> + be32_to_cpu(tpm2_resp->count) != 1) {
> + 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), 1);
> + error_report("tpm_util: Got malformed response to "
> + "TPM2_GetCapability; errcode: 0x%x",
> + be32_to_cpu(tpm2_resp->hdr.errcode));
> + return -EFAULT;
> + }
> + *buffersize = be32_to_cpu(tpm2_resp->value);
> + break;
> + case TPM_VERSION_UNSPEC:
> + break;
> + }
> +
> + DPRINTF("buffersize of device: %u\n", *buffersize);
> +
> + return 0;
> +}
> diff --git a/hw/tpm/tpm_util.h b/hw/tpm/tpm_util.h
> index aca10c9..e4fba32 100644
> --- a/hw/tpm/tpm_util.h
> +++ b/hw/tpm/tpm_util.h
> @@ -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,
> + uint32_t *buffersize);
> +
> #endif /* TPM_TPM_UTIL_H */
> --
> 2.5.5
>
>
Since you pointed out some issues with this patch, I'll review the
next iteration.
- [Qemu-devel] [PATCH 0/5] tpm: Match frontend and backend buffer sizes (not 2.11), Stefan Berger, 2017/11/06
- [Qemu-devel] [PATCH 1/5] tpm: Move getting TPM buffer size to backends, Stefan Berger, 2017/11/06
- [Qemu-devel] [PATCH 2/5] tpm: pull tpm_util_send() out of tpm_util_test(), Stefan Berger, 2017/11/06
- [Qemu-devel] [PATCH 3/5] tpm: tpm_passthrough: Read the buffer size from the host device, Stefan Berger, 2017/11/06
- [Qemu-devel] [PATCH 5/5] tpm: tpm_passthrough: Fail startup if FE buffer size < BE buffer size, Stefan Berger, 2017/11/06
- [Qemu-devel] [PATCH 4/5] tpm: tpm_emulator: get and set buffer size of device, Stefan Berger, 2017/11/06
- Re: [Qemu-devel] [PATCH 0/5] tpm: Match frontend and backend buffer sizes (not 2.11), Marc-André Lureau, 2017/11/08