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[];
  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[];
  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 #define TCG_SPECID_SIG "Spec ID Event03"
  85
  86 struct tcg_efi_specid_event_head {
  87         u8 signature[16];
  88         u32 platform_class;
  89         u8 spec_version_minor;
  90         u8 spec_version_major;
  91         u8 spec_errata;
  92         u8 uintnsize;
  93         u32 num_algs;
  94         struct tcg_efi_specid_event_algs digest_sizes[];
  95 } __packed;
  96
  97 struct tcg_pcr_event {
  98         u32 pcr_idx;
  99         u32 event_type;
 100         u8 digest[20];
 101         u32 event_size;
 102         u8 event[];
 103 } __packed;
 104
 105 struct tcg_event_field {
 106         u32 event_size;
 107         u8 event[];
 108 } __packed;
 109
 110 struct tcg_pcr_event2_head {
 111         u32 pcr_idx;
 112         u32 event_type;
 113         u32 count;
 114         struct tpm_digest digests[];
 115 } __packed;
 116
 117 struct tcg_algorithm_size {
 118         u16 algorithm_id;
 119         u16 algorithm_size;
 120 };
 121
 122 struct tcg_algorithm_info {
 123         u8 signature[16];
 124         u32 platform_class;
 125         u8 spec_version_minor;
 126         u8 spec_version_major;
 127         u8 spec_errata;
 128         u8 uintn_size;
 129         u32 number_of_algorithms;
 130         struct tcg_algorithm_size digest_sizes[];
 131 };
 132
 133 #ifndef TPM_MEMREMAP
 134 #define TPM_MEMREMAP(start, size) NULL
 135 #endif
 136
 137 #ifndef TPM_MEMUNMAP
 138 #define TPM_MEMUNMAP(start, size) do{} while(0)
 139 #endif
 140
 141 /**
 142  * __calc_tpm2_event_size - calculate the size of a TPM2 event log entry
 143  * @event:        Pointer to the event whose size should be calculated
 144  * @event_header: Pointer to the initial event containing the digest lengths
 145  * @do_mapping:   Whether or not the event needs to be mapped
 146  *
 147  * The TPM2 event log format can contain multiple digests corresponding to
 148  * separate PCR banks, and also contains a variable length of the data that
 149  * was measured. This requires knowledge of how long each digest type is,
 150  * and this information is contained within the first event in the log.
 151  *
 152  * We calculate the length by examining the number of events, and then looking
 153  * at each event in turn to determine how much space is used for events in
 154  * total. Once we've done this we know the offset of the data length field,
 155  * and can calculate the total size of the event.
 156  *
 157  * Return: size of the event on success, 0 on failure
 158  */
 159
 160 static __always_inline u32 __calc_tpm2_event_size(struct tcg_pcr_event2_head *event,
 161                                          struct tcg_pcr_event *event_header,
 162                                          bool do_mapping)
 163 {
 164         struct tcg_efi_specid_event_head *efispecid;
 165         struct tcg_event_field *event_field;
 166         void *mapping = NULL;
 167         int mapping_size;
 168         void *marker;
 169         void *marker_start;
 170         u32 halg_size;
 171         size_t size;
 172         u16 halg;
 173         int i;
 174         int j;
 175         u32 count, event_type;
 176         const u8 zero_digest[sizeof(event_header->digest)] = {0};
 177
 178         marker = event;
 179         marker_start = marker;
 180         marker = marker + sizeof(event->pcr_idx) + sizeof(event->event_type)
 181                 + sizeof(event->count);
 182
 183         /* Map the event header */
 184         if (do_mapping) {
 185                 mapping_size = marker - marker_start;
 186                 mapping = TPM_MEMREMAP((unsigned long)marker_start,
 187                                        mapping_size);
 188                 if (!mapping) {
 189                         size = 0;
 190                         goto out;
 191                 }
 192         } else {
 193                 mapping = marker_start;
 194         }
 195
 196         event = (struct tcg_pcr_event2_head *)mapping;
 197         /*
 198          * The loop below will unmap these fields if the log is larger than
 199          * one page, so save them here for reference:
 200          */
 201         count = event->count;
 202         event_type = event->event_type;
 203
 204         /* Verify that it's the log header */
 205         if (event_header->pcr_idx != 0 ||
 206             event_header->event_type != NO_ACTION ||
 207             memcmp(event_header->digest, zero_digest, sizeof(zero_digest))) {
 208                 size = 0;
 209                 goto out;
 210         }
 211
 212         efispecid = (struct tcg_efi_specid_event_head *)event_header->event;
 213
 214         /*
 215          * Perform validation of the event in order to identify malformed
 216          * events. This function may be asked to parse arbitrary byte sequences
 217          * immediately following a valid event log. The caller expects this
 218          * function to recognize that the byte sequence is not a valid event
 219          * and to return an event size of 0.
 220          */
 221         if (memcmp(efispecid->signature, TCG_SPECID_SIG,
 222                    sizeof(TCG_SPECID_SIG)) ||
 223             !efispecid->num_algs || count != efispecid->num_algs) {
 224                 size = 0;
 225                 goto out;
 226         }
 227
 228         for (i = 0; i < count; i++) {
 229                 halg_size = sizeof(event->digests[i].alg_id);
 230
 231                 /* Map the digest's algorithm identifier */
 232                 if (do_mapping) {
 233                         TPM_MEMUNMAP(mapping, mapping_size);
 234                         mapping_size = halg_size;
 235                         mapping = TPM_MEMREMAP((unsigned long)marker,
 236                                              mapping_size);
 237                         if (!mapping) {
 238                                 size = 0;
 239                                 goto out;
 240                         }
 241                 } else {
 242                         mapping = marker;
 243                 }
 244
 245                 memcpy(&halg, mapping, halg_size);
 246                 marker = marker + halg_size;
 247
 248                 for (j = 0; j < efispecid->num_algs; j++) {
 249                         if (halg == efispecid->digest_sizes[j].alg_id) {
 250                                 marker +=
 251                                         efispecid->digest_sizes[j].digest_size;
 252                                 break;
 253                         }
 254                 }
 255                 /* Algorithm without known length. Such event is unparseable. */
 256                 if (j == efispecid->num_algs) {
 257                         size = 0;
 258                         goto out;
 259                 }
 260         }
 261
 262         /*
 263          * Map the event size - we don't read from the event itself, so
 264          * we don't need to map it
 265          */
 266         if (do_mapping) {
 267                 TPM_MEMUNMAP(mapping, mapping_size);
 268                 mapping_size += sizeof(event_field->event_size);
 269                 mapping = TPM_MEMREMAP((unsigned long)marker,
 270                                        mapping_size);
 271                 if (!mapping) {
 272                         size = 0;
 273                         goto out;
 274                 }
 275         } else {
 276                 mapping = marker;
 277         }
 278
 279         event_field = (struct tcg_event_field *)mapping;
 280
 281         marker = marker + sizeof(event_field->event_size)
 282                 + event_field->event_size;
 283         size = marker - marker_start;
 284
 285         if (event_type == 0 && event_field->event_size == 0)
 286                 size = 0;
 287
 288 out:
 289         if (do_mapping)
 290                 TPM_MEMUNMAP(mapping, mapping_size);
 291         return size;
 292 }
 293
 294 #endif