Stefan Berger | 56a3c24 | 2015-05-26 16:51:06 -0400 | [diff] [blame] | 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 | |
Peter Maydell | 0430891 | 2016-01-26 18:17:30 +0000 | [diff] [blame] | 22 | #include "qemu/osdep.h" |
Stefan Berger | 56a3c24 | 2015-05-26 16:51:06 -0400 | [diff] [blame] | 23 | #include "tpm_util.h" |
| 24 | #include "tpm_int.h" |
| 25 | |
| 26 | /* |
Amarnath Valluri | 4a3d809 | 2017-09-29 14:10:19 +0300 | [diff] [blame] | 27 | * Write an error message in the given output buffer. |
| 28 | */ |
| 29 | void tpm_util_write_fatal_error_response(uint8_t *out, uint32_t out_len) |
| 30 | { |
| 31 | if (out_len >= sizeof(struct tpm_resp_hdr)) { |
| 32 | struct tpm_resp_hdr *resp = (struct tpm_resp_hdr *)out; |
| 33 | |
| 34 | resp->tag = cpu_to_be16(TPM_TAG_RSP_COMMAND); |
| 35 | resp->len = cpu_to_be32(sizeof(struct tpm_resp_hdr)); |
| 36 | resp->errcode = cpu_to_be32(TPM_FAIL); |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | bool tpm_util_is_selftest(const uint8_t *in, uint32_t in_len) |
| 41 | { |
| 42 | struct tpm_req_hdr *hdr = (struct tpm_req_hdr *)in; |
| 43 | |
| 44 | if (in_len >= sizeof(*hdr)) { |
| 45 | return (be32_to_cpu(hdr->ordinal) == TPM_ORD_ContinueSelfTest); |
| 46 | } |
| 47 | |
| 48 | return false; |
| 49 | } |
| 50 | |
| 51 | /* |
Stefan Berger | 56a3c24 | 2015-05-26 16:51:06 -0400 | [diff] [blame] | 52 | * A basic test of a TPM device. We expect a well formatted response header |
| 53 | * (error response is fine) within one second. |
| 54 | */ |
| 55 | static int tpm_util_test(int fd, |
| 56 | unsigned char *request, |
| 57 | size_t requestlen, |
| 58 | uint16_t *return_tag) |
| 59 | { |
| 60 | struct tpm_resp_hdr *resp; |
| 61 | fd_set readfds; |
| 62 | int n; |
| 63 | struct timeval tv = { |
| 64 | .tv_sec = 1, |
| 65 | .tv_usec = 0, |
| 66 | }; |
| 67 | unsigned char buf[1024]; |
| 68 | |
| 69 | n = write(fd, request, requestlen); |
| 70 | if (n < 0) { |
Stefan Berger | 98979cd | 2017-10-11 08:52:43 -0400 | [diff] [blame] | 71 | return -errno; |
Stefan Berger | 56a3c24 | 2015-05-26 16:51:06 -0400 | [diff] [blame] | 72 | } |
| 73 | if (n != requestlen) { |
Stefan Berger | 98979cd | 2017-10-11 08:52:43 -0400 | [diff] [blame] | 74 | return -EFAULT; |
Stefan Berger | 56a3c24 | 2015-05-26 16:51:06 -0400 | [diff] [blame] | 75 | } |
| 76 | |
| 77 | FD_ZERO(&readfds); |
| 78 | FD_SET(fd, &readfds); |
| 79 | |
| 80 | /* wait for a second */ |
| 81 | n = select(fd + 1, &readfds, NULL, NULL, &tv); |
| 82 | if (n != 1) { |
Stefan Berger | 98979cd | 2017-10-11 08:52:43 -0400 | [diff] [blame] | 83 | return -errno; |
Stefan Berger | 56a3c24 | 2015-05-26 16:51:06 -0400 | [diff] [blame] | 84 | } |
| 85 | |
| 86 | n = read(fd, &buf, sizeof(buf)); |
| 87 | if (n < sizeof(struct tpm_resp_hdr)) { |
Stefan Berger | 98979cd | 2017-10-11 08:52:43 -0400 | [diff] [blame] | 88 | return -EFAULT; |
Stefan Berger | 56a3c24 | 2015-05-26 16:51:06 -0400 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | resp = (struct tpm_resp_hdr *)buf; |
| 92 | /* check the header */ |
| 93 | if (be32_to_cpu(resp->len) != n) { |
Stefan Berger | 98979cd | 2017-10-11 08:52:43 -0400 | [diff] [blame] | 94 | return -EMSGSIZE; |
Stefan Berger | 56a3c24 | 2015-05-26 16:51:06 -0400 | [diff] [blame] | 95 | } |
| 96 | |
| 97 | *return_tag = be16_to_cpu(resp->tag); |
| 98 | |
| 99 | return 0; |
| 100 | } |
| 101 | |
| 102 | /* |
| 103 | * Probe for the TPM device in the back |
| 104 | * Returns 0 on success with the version of the probed TPM set, 1 on failure. |
| 105 | */ |
| 106 | int tpm_util_test_tpmdev(int tpm_fd, TPMVersion *tpm_version) |
| 107 | { |
| 108 | /* |
| 109 | * Sending a TPM1.2 command to a TPM2 should return a TPM1.2 |
| 110 | * header (tag = 0xc4) and error code (TPM_BADTAG = 0x1e) |
| 111 | * |
| 112 | * Sending a TPM2 command to a TPM 2 will give a TPM 2 tag in the |
| 113 | * header. |
| 114 | * Sending a TPM2 command to a TPM 1.2 will give a TPM 1.2 tag |
| 115 | * in the header and an error code. |
| 116 | */ |
| 117 | const struct tpm_req_hdr test_req = { |
| 118 | .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND), |
| 119 | .len = cpu_to_be32(sizeof(test_req)), |
| 120 | .ordinal = cpu_to_be32(TPM_ORD_GetTicks), |
| 121 | }; |
| 122 | |
| 123 | const struct tpm_req_hdr test_req_tpm2 = { |
| 124 | .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS), |
| 125 | .len = cpu_to_be32(sizeof(test_req_tpm2)), |
| 126 | .ordinal = cpu_to_be32(TPM2_CC_ReadClock), |
| 127 | }; |
| 128 | uint16_t return_tag; |
| 129 | int ret; |
| 130 | |
| 131 | /* Send TPM 2 command */ |
| 132 | ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req_tpm2, |
| 133 | sizeof(test_req_tpm2), &return_tag); |
| 134 | /* TPM 2 would respond with a tag of TPM2_ST_NO_SESSIONS */ |
| 135 | if (!ret && return_tag == TPM2_ST_NO_SESSIONS) { |
| 136 | *tpm_version = TPM_VERSION_2_0; |
| 137 | return 0; |
| 138 | } |
| 139 | |
| 140 | /* Send TPM 1.2 command */ |
| 141 | ret = tpm_util_test(tpm_fd, (unsigned char *)&test_req, |
| 142 | sizeof(test_req), &return_tag); |
| 143 | if (!ret && return_tag == TPM_TAG_RSP_COMMAND) { |
| 144 | *tpm_version = TPM_VERSION_1_2; |
| 145 | /* this is a TPM 1.2 */ |
| 146 | return 0; |
| 147 | } |
| 148 | |
| 149 | *tpm_version = TPM_VERSION_UNSPEC; |
| 150 | |
| 151 | return 1; |
| 152 | } |