include/linux/tpm_eventlog.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2
   3 #ifndef __LINUX_TPM_EVENTLOG_H__
   4 #define __LINUX_TPM_EVENTLOG_H__
   5
   6 #include <linux/tpm.h>
   7
   8 #define TCG_EVENT_NAME_LEN_MAX  255
   9 #define MAX_TEXT_EVENT          1000    /* Max event string length */
  10 #define ACPI_TCPA_SIG           "TCPA"  /* 0x41504354 /'TCPA' */
  11
  12 #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_1_2 0x1
  13 #define EFI_TCG2_EVENT_LOG_FORMAT_TCG_2   0x2
  14
  15 #ifdef CONFIG_PPC64
  16 #define do_endian_conversion(x) be32_to_cpu(x)
  17 #else
  18 #define do_endian_conversion(x) x
  19 #endif
  20
  21 enum bios_platform_class {
  22         BIOS_CLIENT = 0x00,
  23         BIOS_SERVER = 0x01,
  24 };
  25
  26 struct tcpa_event {
  27         u32 pcr_index;
  28         u32 event_type;
  29         u8 pcr_value[20];       /* SHA1 */
  30         u32 event_size;
  31         u8 event_data[0];
  32 };
  33
  34 enum tcpa_event_types {
  35         PREBOOT = 0,
  36         POST_CODE,
  37         UNUSED,
  38         NO_ACTION,
  39         SEPARATOR,
  40         ACTION,
  41         EVENT_TAG,
  42         SCRTM_CONTENTS,
  43         SCRTM_VERSION,
  44         CPU_MICROCODE,
  45         PLATFORM_CONFIG_FLAGS,
  46         TABLE_OF_DEVICES,
  47         COMPACT_HASH,
  48         IPL,
  49         IPL_PARTITION_DATA,
  50         NONHOST_CODE,
  51         NONHOST_CONFIG,
  52         NONHOST_INFO,
  53 };
  54
  55 struct tcpa_pc_event {
  56         u32 event_id;
  57         u32 event_size;
  58         u8 event_data[0];
  59 };
  60
  61 enum tcpa_pc_event_ids {
  62         SMBIOS = 1,
  63         BIS_CERT,
  64         POST_BIOS_ROM,
  65         ESCD,
  66         CMOS,
  67         NVRAM,
  68         OPTION_ROM_EXEC,
  69         OPTION_ROM_CONFIG,
  70         OPTION_ROM_MICROCODE = 10,
  71         S_CRTM_VERSION,
  72         S_CRTM_CONTENTS,
  73         POST_CONTENTS,
  74         HOST_TABLE_OF_DEVICES,
  75 };
  76
  77 /* http://www.trustedcomputinggroup.org/tcg-efi-protocol-specification/ */
  78
  79 struct tcg_efi_specid_event_algs {
  80         u16 alg_id;
  81         u16 digest_size;
  82 } __packed;
  83
  84 struct tcg_efi_specid_event_head {
  85         u8 signature[16];
  86         u32 platform_class;
  87         u8 spec_version_minor;
  88         u8 spec_version_major;
  89         u8 spec_errata;
  90         u8 uintnsize;
  91         u32 num_algs;
  92         struct tcg_efi_specid_event_algs digest_sizes[];
  93 } __packed;
  94
  95 struct tcg_pcr_event {
  96         u32 pcr_idx;
  97         u32 event_type;
  98         u8 digest[20];
  99         u32 event_size;
 100         u8 event[0];
 101 } __packed;
 102
 103 struct tcg_event_field {
 104         u32 event_size;
 105         u8 event[0];
 106 } __packed;
 107
 108 struct tcg_pcr_event2_head {
 109         u32 pcr_idx;
 110         u32 event_type;
 111         u32 count;
 112         struct tpm_digest digests[];
 113 } __packed;
 114
 115 struct tcg_algorithm_size {
 116         u16 algorithm_id;
 117         u16 algorithm_size;
 118 };
 119
 120 struct tcg_algorithm_info {
 121         u8 signature[16];
 122         u32 platform_class;
 123         u8 spec_version_minor;
 124         u8 spec_version_major;
 125         u8 spec_errata;
 126         u8 uintn_size;
 127         u32 number_of_algorithms;
 128         struct tcg_algorithm_size digest_sizes[];
 129 };
 130
 131 #ifndef TPM_MEMREMAP
 132 #define TPM_MEMREMAP(start, size) NULL
 133 #endif
 134
 135 #ifndef TPM_MEMUNMAP
 136 #define TPM_MEMUNMAP(start, size) do{} while(0)
 137 #endif
 138
 139 /**
 140  * __calc_tpm2_event_size - calculate the size of a TPM2 event log entry
 141  * @event:        Pointer to the event whose size should be calculated
 142  * @event_header: Pointer to the initial event containing the digest lengths
 143  * @do_mapping:   Whether or not the event needs to be mapped
 144  *
 145  * The TPM2 event log format can contain multiple digests corresponding to
 146  * separate PCR banks, and also contains a variable length of the data that
 147  * was measured. This requires knowledge of how long each digest type is,
 148  * and this information is contained within the first event in the log.
 149  *
 150  * We calculate the length by examining the number of events, and then looking
 151  * at each event in turn to determine how much space is used for events in
 152  * total. Once we've done this we know the offset of the data length field,
 153  * and can calculate the total size of the event.
 154  *
 155  * Return: size of the event on success, 0 on failure
 156  */
 157
 158 static inline int __calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
 159                                          struct tcg_pcr_event *event_header,
 160                                          bool do_mapping)
 161 {
 162         struct tcg_efi_specid_event_head *efispecid;
 163         struct tcg_event_field *event_field;
 164         void *mapping = NULL;
 165         int mapping_size;
 166         void *marker;
 167         void *marker_start;
 168         u32 halg_size;
 169         size_t size;
 170         u16 halg;
 171         int i;
 172         int j;
 173         u32 count, event_type;
 174
 175         marker = event;
 176         marker_start = marker;
 177         marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
 178                 + sizeof(event->count);
 179
 180         /* Map the event header */
 181         if (do_mapping) {
 182                 mapping_size = marker - marker_start;
 183                 mapping = TPM_MEMREMAP((unsigned long)marker_start,
 184                                        mapping_size);
 185                 if (!mapping) {
 186                         size = 0;
 187                         goto out;
 188                 }
 189         } else {
 190                 mapping = marker_start;
 191         }
 192
 193         event = (struct tcg_pcr_event2_head *)mapping;
 194         /*
 195          * The loop below will unmap these fields if the log is larger than
 196          * one page, so save them here for reference:
 197          */
 198         count = READ_ONCE(event->count);
 199         event_type = READ_ONCE(event->event_type);
 200
 201         efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
 202
 203         /* Check if event is malformed. */
 204         if (count > efispecid->num_algs) {
 205                 size = 0;
 206                 goto out;
 207         }
 208
 209         for (i = 0; i < count; i++) {
 210                 halg_size = sizeof(event->digests[i].alg_id);
 211
 212                 /* Map the digest's algorithm identifier */
 213                 if (do_mapping) {
 214                         TPM_MEMUNMAP(mapping, mapping_size);
 215                         mapping_size = halg_size;
 216                         mapping = TPM_MEMREMAP((unsigned long)marker,
 217                                              mapping_size);
 218                         if (!mapping) {
 219                                 size = 0;
 220                                 goto out;
 221                         }
 222                 } else {
 223                         mapping = marker;
 224                 }
 225
 226                 memcpy(&halg, mapping, halg_size);
 227                 marker = marker + halg_size;
 228
 229                 for (j = 0; j < efispecid->num_algs; j++) {
 230                         if (halg == efispecid->digest_sizes[j].alg_id) {
 231                                 marker +=
 232                                         efispecid->digest_sizes[j].digest_size;
 233                                 break;
 234                         }
 235                 }
 236                 /* Algorithm without known length. Such event is unparseable. */
 237                 if (j == efispecid->num_algs) {
 238                         size = 0;
 239                         goto out;
 240                 }
 241         }
 242
 243         /*
 244          * Map the event size - we don't read from the event itself, so
 245          * we don't need to map it
 246          */
 247         if (do_mapping) {
 248                 TPM_MEMUNMAP(mapping, mapping_size);
 249                 mapping_size += sizeof(event_field->event_size);
 250                 mapping = TPM_MEMREMAP((unsigned long)marker,
 251                                        mapping_size);
 252                 if (!mapping) {
 253                         size = 0;
 254                         goto out;
 255                 }
 256         } else {
 257                 mapping = marker;
 258         }
 259
 260         event_field = (struct tcg_event_field *)mapping;
 261
 262         marker = marker + sizeof(event_field->event_size)
 263                 + event_field->event_size;
 264         size = marker - marker_start;
 265
 266         if (event_type == 0 && event_field->event_size == 0)
 267                 size = 0;
 268
 269 out:
 270         if (do_mapping)
 271                 TPM_MEMUNMAP(mapping, mapping_size);
 272         return size;
 273 }
 274
 275 #endif