drivers/char/tpm/tpm1_eventlog.c

   1 /*
   2  * Copyright (C) 2005, 2012 IBM Corporation
   3  *
   4  * Authors:
   5  *      Kent Yoder <key@linux.vnet.ibm.com>
   6  *      Seiji Munetoh <munetoh@jp.ibm.com>
   7  *      Stefan Berger <stefanb@us.ibm.com>
   8  *      Reiner Sailer <sailer@watson.ibm.com>
   9  *      Kylene Hall <kjhall@us.ibm.com>
  10  *      Nayna Jain <nayna@linux.vnet.ibm.com>
  11  *
  12  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  13  *
  14  * Access to the event log created by a system's firmware / BIOS
  15  *
  16  * This program is free software; you can redistribute it and/or
  17  * modify it under the terms of the GNU General Public License
  18  * as published by the Free Software Foundation; either version
  19  * 2 of the License, or (at your option) any later version.
  20  *
  21  */
  22
  23 #include <linux/seq_file.h>
  24 #include <linux/efi.h>
  25 #include <linux/fs.h>
  26 #include <linux/security.h>
  27 #include <linux/module.h>
  28 #include <linux/slab.h>
  29 #include <linux/tpm_eventlog.h>
  30
  31 #include "tpm.h"
  32
  33
  34 static const char* tcpa_event_type_strings[] = {
  35         "PREBOOT",
  36         "POST CODE",
  37         "",
  38         "NO ACTION",
  39         "SEPARATOR",
  40         "ACTION",
  41         "EVENT TAG",
  42         "S-CRTM Contents",
  43         "S-CRTM Version",
  44         "CPU Microcode",
  45         "Platform Config Flags",
  46         "Table of Devices",
  47         "Compact Hash",
  48         "IPL",
  49         "IPL Partition Data",
  50         "Non-Host Code",
  51         "Non-Host Config",
  52         "Non-Host Info"
  53 };
  54
  55 static const char* tcpa_pc_event_id_strings[] = {
  56         "",
  57         "SMBIOS",
  58         "BIS Certificate",
  59         "POST BIOS ",
  60         "ESCD ",
  61         "CMOS",
  62         "NVRAM",
  63         "Option ROM",
  64         "Option ROM config",
  65         "",
  66         "Option ROM microcode ",
  67         "S-CRTM Version",
  68         "S-CRTM Contents ",
  69         "POST Contents ",
  70         "Table of Devices",
  71 };
  72
  73 /* returns pointer to start of pos. entry of tcg log */
  74 static void *tpm_bios_measurements_start(struct seq_file *m, loff_t *pos)
  75 {
  76         loff_t i;
  77         struct tpm_chip *chip = m->private;
  78         struct tpm_bios_log *log = &chip->log;
  79         void *addr = log->bios_event_log;
  80         void *limit = log->bios_event_log_end;
  81         struct tcpa_event *event;
  82         u32 converted_event_size;
  83         u32 converted_event_type;
  84
  85
  86         /* read over *pos measurements */
  87         for (i = 0; i < *pos; i++) {
  88                 event = addr;
  89
  90                 converted_event_size =
  91                     do_endian_conversion(event->event_size);
  92                 converted_event_type =
  93                     do_endian_conversion(event->event_type);
  94
  95                 if ((addr + sizeof(struct tcpa_event)) < limit) {
  96                         if ((converted_event_type == 0) &&
  97                             (converted_event_size == 0))
  98                                 return NULL;
  99                         addr += (sizeof(struct tcpa_event) +
 100                                  converted_event_size);
 101                 }
 102         }
 103
 104         /* now check if current entry is valid */
 105         if ((addr + sizeof(struct tcpa_event)) >= limit)
 106                 return NULL;
 107
 108         event = addr;
 109
 110         converted_event_size = do_endian_conversion(event->event_size);
 111         converted_event_type = do_endian_conversion(event->event_type);
 112
 113         if (((converted_event_type == 0) && (converted_event_size == 0))
 114             || ((addr + sizeof(struct tcpa_event) + converted_event_size)
 115                 >= limit))
 116                 return NULL;
 117
 118         return addr;
 119 }
 120
 121 static void *tpm_bios_measurements_next(struct seq_file *m, void *v,
 122                                         loff_t *pos)
 123 {
 124         struct tcpa_event *event = v;
 125         struct tpm_chip *chip = m->private;
 126         struct tpm_bios_log *log = &chip->log;
 127         void *limit = log->bios_event_log_end;
 128         u32 converted_event_size;
 129         u32 converted_event_type;
 130
 131         converted_event_size = do_endian_conversion(event->event_size);
 132
 133         v += sizeof(struct tcpa_event) + converted_event_size;
 134
 135         /* now check if current entry is valid */
 136         if ((v + sizeof(struct tcpa_event)) >= limit)
 137                 return NULL;
 138
 139         event = v;
 140
 141         converted_event_size = do_endian_conversion(event->event_size);
 142         converted_event_type = do_endian_conversion(event->event_type);
 143
 144         if (((converted_event_type == 0) && (converted_event_size == 0)) ||
 145             ((v + sizeof(struct tcpa_event) + converted_event_size) >= limit))
 146                 return NULL;
 147
 148         (*pos)++;
 149         return v;
 150 }
 151
 152 static void tpm_bios_measurements_stop(struct seq_file *m, void *v)
 153 {
 154 }
 155
 156 static int get_event_name(char *dest, struct tcpa_event *event,
 157                         unsigned char * event_entry)
 158 {
 159         const char *name = "";
 160         /* 41 so there is room for 40 data and 1 nul */
 161         char data[41] = "";
 162         int i, n_len = 0, d_len = 0;
 163         struct tcpa_pc_event *pc_event;
 164
 165         switch (do_endian_conversion(event->event_type)) {
 166         case PREBOOT:
 167         case POST_CODE:
 168         case UNUSED:
 169         case NO_ACTION:
 170         case SCRTM_CONTENTS:
 171         case SCRTM_VERSION:
 172         case CPU_MICROCODE:
 173         case PLATFORM_CONFIG_FLAGS:
 174         case TABLE_OF_DEVICES:
 175         case COMPACT_HASH:
 176         case IPL:
 177         case IPL_PARTITION_DATA:
 178         case NONHOST_CODE:
 179         case NONHOST_CONFIG:
 180         case NONHOST_INFO:
 181                 name = tcpa_event_type_strings[do_endian_conversion
 182                                                 (event->event_type)];
 183                 n_len = strlen(name);
 184                 break;
 185         case SEPARATOR:
 186         case ACTION:
 187                 if (MAX_TEXT_EVENT >
 188                     do_endian_conversion(event->event_size)) {
 189                         name = event_entry;
 190                         n_len = do_endian_conversion(event->event_size);
 191                 }
 192                 break;
 193         case EVENT_TAG:
 194                 pc_event = (struct tcpa_pc_event *)event_entry;
 195
 196                 /* ToDo Row data -> Base64 */
 197
 198                 switch (do_endian_conversion(pc_event->event_id)) {
 199                 case SMBIOS:
 200                 case BIS_CERT:
 201                 case CMOS:
 202                 case NVRAM:
 203                 case OPTION_ROM_EXEC:
 204                 case OPTION_ROM_CONFIG:
 205                 case S_CRTM_VERSION:
 206                         name = tcpa_pc_event_id_strings[do_endian_conversion
 207                                                         (pc_event->event_id)];
 208                         n_len = strlen(name);
 209                         break;
 210                 /* hash data */
 211                 case POST_BIOS_ROM:
 212                 case ESCD:
 213                 case OPTION_ROM_MICROCODE:
 214                 case S_CRTM_CONTENTS:
 215                 case POST_CONTENTS:
 216                         name = tcpa_pc_event_id_strings[do_endian_conversion
 217                                                         (pc_event->event_id)];
 218                         n_len = strlen(name);
 219                         for (i = 0; i < 20; i++)
 220                                 d_len += sprintf(&data[2*i], "%02x",
 221                                                 pc_event->event_data[i]);
 222                         break;
 223                 default:
 224                         break;
 225                 }
 226         default:
 227                 break;
 228         }
 229
 230         return snprintf(dest, MAX_TEXT_EVENT, "[%.*s%.*s]",
 231                         n_len, name, d_len, data);
 232
 233 }
 234
 235 static int tpm_binary_bios_measurements_show(struct seq_file *m, void *v)
 236 {
 237         struct tcpa_event *event = v;
 238         struct tcpa_event temp_event;
 239         char *temp_ptr;
 240         int i;
 241
 242         memcpy(&temp_event, event, sizeof(struct tcpa_event));
 243
 244         /* convert raw integers for endianness */
 245         temp_event.pcr_index = do_endian_conversion(event->pcr_index);
 246         temp_event.event_type = do_endian_conversion(event->event_type);
 247         temp_event.event_size = do_endian_conversion(event->event_size);
 248
 249         temp_ptr = (char *) &temp_event;
 250
 251         for (i = 0; i < (sizeof(struct tcpa_event) - 1) ; i++)
 252                 seq_putc(m, temp_ptr[i]);
 253
 254         temp_ptr = (char *) v;
 255
 256         for (i = (sizeof(struct tcpa_event) - 1);
 257              i < (sizeof(struct tcpa_event) + temp_event.event_size); i++)
 258                 seq_putc(m, temp_ptr[i]);
 259
 260         return 0;
 261
 262 }
 263
 264 static int tpm_bios_measurements_release(struct inode *inode,
 265                                          struct file *file)
 266 {
 267         struct seq_file *seq = (struct seq_file *)file->private_data;
 268         struct tpm_chip *chip = (struct tpm_chip *)seq->private;
 269
 270         put_device(&chip->dev);
 271
 272         return seq_release(inode, file);
 273 }
 274
 275 static int tpm_ascii_bios_measurements_show(struct seq_file *m, void *v)
 276 {
 277         int len = 0;
 278         char *eventname;
 279         struct tcpa_event *event = v;
 280         unsigned char *event_entry =
 281             (unsigned char *)(v + sizeof(struct tcpa_event));
 282
 283         eventname = kmalloc(MAX_TEXT_EVENT, GFP_KERNEL);
 284         if (!eventname) {
 285                 printk(KERN_ERR "%s: ERROR - No Memory for event name\n ",
 286                        __func__);
 287                 return -EFAULT;
 288         }
 289
 290         /* 1st: PCR */
 291         seq_printf(m, "%2d ", do_endian_conversion(event->pcr_index));
 292
 293         /* 2nd: SHA1 */
 294         seq_printf(m, "%20phN", event->pcr_value);
 295
 296         /* 3rd: event type identifier */
 297         seq_printf(m, " %02x", do_endian_conversion(event->event_type));
 298
 299         len += get_event_name(eventname, event, event_entry);
 300
 301         /* 4th: eventname <= max + \'0' delimiter */
 302         seq_printf(m, " %s\n", eventname);
 303
 304         kfree(eventname);
 305         return 0;
 306 }
 307
 308 static const struct seq_operations tpm_ascii_b_measurements_seqops = {
 309         .start = tpm_bios_measurements_start,
 310         .next = tpm_bios_measurements_next,
 311         .stop = tpm_bios_measurements_stop,
 312         .show = tpm_ascii_bios_measurements_show,
 313 };
 314
 315 static const struct seq_operations tpm_binary_b_measurements_seqops = {
 316         .start = tpm_bios_measurements_start,
 317         .next = tpm_bios_measurements_next,
 318         .stop = tpm_bios_measurements_stop,
 319         .show = tpm_binary_bios_measurements_show,
 320 };
 321
 322 static int tpm_bios_measurements_open(struct inode *inode,
 323                                             struct file *file)
 324 {
 325         int err;
 326         struct seq_file *seq;
 327         struct tpm_chip_seqops *chip_seqops;
 328         const struct seq_operations *seqops;
 329         struct tpm_chip *chip;
 330
 331         inode_lock(inode);
 332         if (!inode->i_private) {
 333                 inode_unlock(inode);
 334                 return -ENODEV;
 335         }
 336         chip_seqops = (struct tpm_chip_seqops *)inode->i_private;
 337         seqops = chip_seqops->seqops;
 338         chip = chip_seqops->chip;
 339         get_device(&chip->dev);
 340         inode_unlock(inode);
 341
 342         /* now register seq file */
 343         err = seq_open(file, seqops);
 344         if (!err) {
 345                 seq = file->private_data;
 346                 seq->private = chip;
 347         }
 348
 349         return err;
 350 }
 351
 352 static const struct file_operations tpm_bios_measurements_ops = {
 353         .owner = THIS_MODULE,
 354         .open = tpm_bios_measurements_open,
 355         .read = seq_read,
 356         .llseek = seq_lseek,
 357         .release = tpm_bios_measurements_release,
 358 };
 359
 360 static int tpm_read_log(struct tpm_chip *chip)
 361 {
 362         int rc;
 363
 364         if (chip->log.bios_event_log != NULL) {
 365                 dev_dbg(&chip->dev,
 366                         "%s: ERROR - event log already initialized\n",
 367                         __func__);
 368                 return -EFAULT;
 369         }
 370
 371         rc = tpm_read_log_acpi(chip);
 372         if (rc != -ENODEV)
 373                 return rc;
 374
 375         rc = tpm_read_log_efi(chip);
 376         if (rc != -ENODEV)
 377                 return rc;
 378
 379         return tpm_read_log_of(chip);
 380 }
 381
 382 /*
 383  * tpm_bios_log_setup() - Read the event log from the firmware
 384  * @chip: TPM chip to use.
 385  *
 386  * If an event log is found then the securityfs files are setup to
 387  * export it to userspace, otherwise nothing is done.
 388  *
 389  * Returns -ENODEV if the firmware has no event log or securityfs is not
 390  * supported.
 391  */
 392 int tpm_bios_log_setup(struct tpm_chip *chip)
 393 {
 394         const char *name = dev_name(&chip->dev);
 395         unsigned int cnt;
 396         int log_version;
 397         int rc = 0;
 398
 399         rc = tpm_read_log(chip);
 400         if (rc < 0)
 401                 return rc;
 402         log_version = rc;
 403
 404         cnt = 0;
 405         chip->bios_dir[cnt] = securityfs_create_dir(name, NULL);
 406         /* NOTE: securityfs_create_dir can return ENODEV if securityfs is
 407          * compiled out. The caller should ignore the ENODEV return code.
 408          */
 409         if (IS_ERR(chip->bios_dir[cnt]))
 410                 goto err;
 411         cnt++;
 412
 413         chip->bin_log_seqops.chip = chip;
 414         if (log_version == EFI_TCG2_EVENT_LOG_FORMAT_TCG_2)
 415                 chip->bin_log_seqops.seqops =
 416                         &tpm2_binary_b_measurements_seqops;
 417         else
 418                 chip->bin_log_seqops.seqops =
 419                         &tpm_binary_b_measurements_seqops;
 420
 421
 422         chip->bios_dir[cnt] =
 423             securityfs_create_file("binary_bios_measurements",
 424                                    0440, chip->bios_dir[0],
 425                                    (void *)&chip->bin_log_seqops,
 426                                    &tpm_bios_measurements_ops);
 427         if (IS_ERR(chip->bios_dir[cnt]))
 428                 goto err;
 429         cnt++;
 430
 431         if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
 432
 433                 chip->ascii_log_seqops.chip = chip;
 434                 chip->ascii_log_seqops.seqops =
 435                         &tpm_ascii_b_measurements_seqops;
 436
 437                 chip->bios_dir[cnt] =
 438                         securityfs_create_file("ascii_bios_measurements",
 439                                                0440, chip->bios_dir[0],
 440                                                (void *)&chip->ascii_log_seqops,
 441                                                &tpm_bios_measurements_ops);
 442                 if (IS_ERR(chip->bios_dir[cnt]))
 443                         goto err;
 444                 cnt++;
 445         }
 446
 447         return 0;
 448
 449 err:
 450         rc = PTR_ERR(chip->bios_dir[cnt]);
 451         chip->bios_dir[cnt] = NULL;
 452         tpm_bios_log_teardown(chip);
 453         return rc;
 454 }
 455
 456 void tpm_bios_log_teardown(struct tpm_chip *chip)
 457 {
 458         int i;
 459         struct inode *inode;
 460
 461         /* securityfs_remove currently doesn't take care of handling sync
 462          * between removal and opening of pseudo files. To handle this, a
 463          * workaround is added by making i_private = NULL here during removal
 464          * and to check it during open(), both within inode_lock()/unlock().
 465          * This design ensures that open() either safely gets kref or fails.
 466          */
 467         for (i = (TPM_NUM_EVENT_LOG_FILES - 1); i >= 0; i--) {
 468                 if (chip->bios_dir[i]) {
 469                         inode = d_inode(chip->bios_dir[i]);
 470                         inode_lock(inode);
 471                         inode->i_private = NULL;
 472                         inode_unlock(inode);
 473                         securityfs_remove(chip->bios_dir[i]);
 474                 }
 475         }
 476 }