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