diff options
Diffstat (limited to 'backends/tpm/tpm_util.c')
| -rw-r--r-- | backends/tpm/tpm_util.c | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/backends/tpm/tpm_util.c b/backends/tpm/tpm_util.c new file mode 100644 index 000000000..a6e6d3e72 --- /dev/null +++ b/backends/tpm/tpm_util.c @@ -0,0 +1,369 @@ +/* + * 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 2.1 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_int.h" +#include "exec/memory.h" +#include "hw/qdev-properties.h" +#include "sysemu/tpm_backend.h" +#include "sysemu/tpm_util.h" +#include "trace.h" + +/* tpm backend property */ + +static void get_tpm(Object *obj, Visitor *v, const char *name, void *opaque, + Error **errp) +{ + TPMBackend **be = object_field_prop_ptr(obj, 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) +{ + Property *prop = opaque; + TPMBackend *s, **be = object_field_prop_ptr(obj, prop); + char *str; + + if (!visit_type_str(v, name, &str, errp)) { + 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), 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) +{ + Property *prop = opaque; + TPMBackend **be = object_field_prop_ptr(obj, 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)) { + trace_tpm_util_get_buffer_size_hdr_len( + be32_to_cpu(tpm_resp.hdr.len), + sizeof(tpm_resp)); + trace_tpm_util_get_buffer_size_len(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) { + trace_tpm_util_get_buffer_size_hdr_len2( + be32_to_cpu(tpm2_resp.hdr.len), + sizeof(tpm2_resp)); + trace_tpm_util_get_buffer_size_len2( + 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; + } + + trace_tpm_util_get_buffer_size(*buffersize); + + return 0; +} + +void tpm_sized_buffer_reset(TPMSizedBuffer *tsb) +{ + g_free(tsb->buffer); + tsb->buffer = NULL; + tsb->size = 0; +} + +void tpm_util_show_buffer(const unsigned char *buffer, + size_t buffer_size, const char *string) +{ + size_t len, i; + char *line_buffer, *p; + + if (!trace_event_get_state_backends(TRACE_TPM_UTIL_SHOW_BUFFER)) { + return; + } + len = MIN(tpm_cmd_get_size(buffer), buffer_size); + + /* + * allocate enough room for 3 chars per buffer entry plus a + * newline after every 16 chars and a final null terminator. + */ + line_buffer = g_malloc(len * 3 + (len / 16) + 1); + + for (i = 0, p = line_buffer; i < len; i++) { + if (i && !(i % 16)) { + p += sprintf(p, "\n"); + } + p += sprintf(p, "%.2X ", buffer[i]); + } + trace_tpm_util_show_buffer(string, len, line_buffer); + + g_free(line_buffer); +} |