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  *
  11  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
  12  *
  13  * Access to the eventlog created by a system's firmware / BIOS
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version
  18  * 2 of the License, or (at your option) any later version.
  19  *
  20  */
  21
  22 #include <linux/seq_file.h>
  23 #include <linux/fs.h>
  24 #include <linux/security.h>
  25 #include <linux/module.h>
  26 #include <linux/slab.h>
  27
  28 #include "tpm.h"
  29 #include "tpm_eventlog.h"
  30
  31
  32 static const char* tcpa_event_type_strings[] = {
  33         "PREBOOT",
  34         "POST CODE",
  35         "",
  36         "NO ACTION",
  37         "SEPARATOR",
  38         "ACTION",
  39         "EVENT TAG",
  40         "S-CRTM Contents",
  41         "S-CRTM Version",
  42         "CPU Microcode",
  43         "Platform Config Flags",
  44         "Table of Devices",
  45         "Compact Hash",
  46         "IPL",
  47         "IPL Partition Data",
  48         "Non-Host Code",
  49         "Non-Host Config",
  50         "Non-Host Info"
  51 };
  52
  53 static const char* tcpa_pc_event_id_strings[] = {
  54         "",
  55         "SMBIOS",
  56         "BIS Certificate",
  57         "POST BIOS ",
  58         "ESCD ",
  59         "CMOS",
  60         "NVRAM",
  61         "Option ROM",
  62         "Option ROM config",
  63         "",
  64         "Option ROM microcode ",
  65         "S-CRTM Version",
  66         "S-CRTM Contents ",
  67         "POST Contents ",
  68         "Table of Devices",
  69 };
  70
  71 /* returns pointer to start of pos. entry of tcg log */
  72 static void *tpm_bios_measurements_start(struct seq_file *m, loff_t *pos)
  73 {
  74         loff_t i;
  75         struct tpm_bios_log *log = m->private;
  76         void *addr = log->bios_event_log;
  77         void *limit = log->bios_event_log_end;
  78         struct tcpa_event *event;
  79         u32 converted_event_size;
  80         u32 converted_event_type;
  81
  82
  83         /* read over *pos measurements */
  84         for (i = 0; i < *pos; i++) {
  85                 event = addr;
  86
  87                 converted_event_size =
  88                     do_endian_conversion(event->event_size);
  89                 converted_event_type =
  90                     do_endian_conversion(event->event_type);
  91
  92                 if ((addr + sizeof(struct tcpa_event)) < limit) {
  93                         if ((converted_event_type == 0) &&
  94                             (converted_event_size == 0))
  95                                 return NULL;
  96                         addr += (sizeof(struct tcpa_event) +
  97                                  converted_event_size);
  98                 }
  99         }
 100
 101         /* now check if current entry is valid */
 102         if ((addr + sizeof(struct tcpa_event)) >= limit)
 103                 return NULL;
 104
 105         event = addr;
 106
 107         converted_event_size = do_endian_conversion(event->event_size);
 108         converted_event_type = do_endian_conversion(event->event_type);
 109
 110         if (((converted_event_type == 0) && (converted_event_size == 0))
 111             || ((addr + sizeof(struct tcpa_event) + converted_event_size)
 112                 >= limit))
 113                 return NULL;
 114
 115         return addr;
 116 }
 117
 118 static void *tpm_bios_measurements_next(struct seq_file *m, void *v,
 119                                         loff_t *pos)
 120 {
 121         struct tcpa_event *event = v;
 122         struct tpm_bios_log *log = m->private;
 123         void *limit = log->bios_event_log_end;
 124         u32 converted_event_size;
 125         u32 converted_event_type;
 126
 127         converted_event_size = do_endian_conversion(event->event_size);
 128
 129         v += sizeof(struct tcpa_event) + converted_event_size;
 130
 131         /* now check if current entry is valid */
 132         if ((v + sizeof(struct tcpa_event)) >= limit)
 133                 return NULL;
 134
 135         event = v;
 136
 137         converted_event_size = do_endian_conversion(event->event_size);
 138         converted_event_type = do_endian_conversion(event->event_type);
 139
 140         if (((converted_event_type == 0) && (converted_event_size == 0)) ||
 141             ((v + sizeof(struct tcpa_event) + converted_event_size) >= limit))
 142                 return NULL;
 143
 144         (*pos)++;
 145         return v;
 146 }
 147
 148 static void tpm_bios_measurements_stop(struct seq_file *m, void *v)
 149 {
 150 }
 151
 152 static int get_event_name(char *dest, struct tcpa_event *event,
 153                         unsigned char * event_entry)
 154 {
 155         const char *name = "";
 156         /* 41 so there is room for 40 data and 1 nul */
 157         char data[41] = "";
 158         int i, n_len = 0, d_len = 0;
 159         struct tcpa_pc_event *pc_event;
 160
 161         switch (do_endian_conversion(event->event_type)) {
 162         case PREBOOT:
 163         case POST_CODE:
 164         case UNUSED:
 165         case NO_ACTION:
 166         case SCRTM_CONTENTS:
 167         case SCRTM_VERSION:
 168         case CPU_MICROCODE:
 169         case PLATFORM_CONFIG_FLAGS:
 170         case TABLE_OF_DEVICES:
 171         case COMPACT_HASH:
 172         case IPL:
 173         case IPL_PARTITION_DATA:
 174         case NONHOST_CODE:
 175         case NONHOST_CONFIG:
 176         case NONHOST_INFO:
 177                 name = tcpa_event_type_strings[do_endian_conversion
 178                                                 (event->event_type)];
 179                 n_len = strlen(name);
 180                 break;
 181         case SEPARATOR:
 182         case ACTION:
 183                 if (MAX_TEXT_EVENT >
 184                     do_endian_conversion(event->event_size)) {
 185                         name = event_entry;
 186                         n_len = do_endian_conversion(event->event_size);
 187                 }
 188                 break;
 189         case EVENT_TAG:
 190                 pc_event = (struct tcpa_pc_event *)event_entry;
 191
 192                 /* ToDo Row data -> Base64 */
 193
 194                 switch (do_endian_conversion(pc_event->event_id)) {
 195                 case SMBIOS:
 196                 case BIS_CERT:
 197                 case CMOS:
 198                 case NVRAM:
 199                 case OPTION_ROM_EXEC:
 200                 case OPTION_ROM_CONFIG:
 201                 case S_CRTM_VERSION:
 202                         name = tcpa_pc_event_id_strings[do_endian_conversion
 203                                                         (pc_event->event_id)];
 204                         n_len = strlen(name);
 205                         break;
 206                 /* hash data */
 207                 case POST_BIOS_ROM:
 208                 case ESCD:
 209                 case OPTION_ROM_MICROCODE:
 210                 case S_CRTM_CONTENTS:
 211                 case POST_CONTENTS:
 212                         name = tcpa_pc_event_id_strings[do_endian_conversion
 213                                                         (pc_event->event_id)];
 214                         n_len = strlen(name);
 215                         for (i = 0; i < 20; i++)
 216                                 d_len += sprintf(&data[2*i], "%02x",
 217                                                 pc_event->event_data[i]);
 218                         break;
 219                 default:
 220                         break;
 221                 }
 222         default:
 223                 break;
 224         }
 225
 226         return snprintf(dest, MAX_TEXT_EVENT, "[%.*s%.*s]",
 227                         n_len, name, d_len, data);
 228
 229 }
 230
 231 static int tpm_binary_bios_measurements_show(struct seq_file *m, void *v)
 232 {
 233         struct tcpa_event *event = v;
 234         struct tcpa_event temp_event;
 235         char *temp_ptr;
 236         int i;
 237
 238         memcpy(&temp_event, event, sizeof(struct tcpa_event));
 239
 240         /* convert raw integers for endianness */
 241         temp_event.pcr_index = do_endian_conversion(event->pcr_index);
 242         temp_event.event_type = do_endian_conversion(event->event_type);
 243         temp_event.event_size = do_endian_conversion(event->event_size);
 244
 245         temp_ptr = (char *) &temp_event;
 246
 247         for (i = 0; i < (sizeof(struct tcpa_event) - 1) ; i++)
 248                 seq_putc(m, temp_ptr[i]);
 249
 250         temp_ptr = (char *) v;
 251
 252         for (i = (sizeof(struct tcpa_event) - 1);
 253              i < (sizeof(struct tcpa_event) + temp_event.event_size); i++)
 254                 seq_putc(m, temp_ptr[i]);
 255
 256         return 0;
 257
 258 }
 259
 260 static int tpm_bios_measurements_release(struct inode *inode,
 261                                          struct file *file)
 262 {
 263         struct seq_file *seq = file->private_data;
 264         struct tpm_bios_log *log = seq->private;
 265
 266         if (log) {
 267                 kfree(log->bios_event_log);
 268                 kfree(log);
 269         }
 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_measurments_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_measurments_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_ascii_bios_measurements_open(struct inode *inode,
 322                                             struct file *file)
 323 {
 324         int err;
 325         struct tpm_bios_log *log;
 326         struct seq_file *seq;
 327
 328         log = kzalloc(sizeof(struct tpm_bios_log), GFP_KERNEL);
 329         if (!log)
 330                 return -ENOMEM;
 331
 332         if ((err = read_log(log)))
 333                 goto out_free;
 334
 335         /* now register seq file */
 336         err = seq_open(file, &tpm_ascii_b_measurments_seqops);
 337         if (!err) {
 338                 seq = file->private_data;
 339                 seq->private = log;
 340         } else {
 341                 goto out_free;
 342         }
 343
 344 out:
 345         return err;
 346 out_free:
 347         kfree(log->bios_event_log);
 348         kfree(log);
 349         goto out;
 350 }
 351
 352 static const struct file_operations tpm_ascii_bios_measurements_ops = {
 353         .open = tpm_ascii_bios_measurements_open,
 354         .read = seq_read,
 355         .llseek = seq_lseek,
 356         .release = tpm_bios_measurements_release,
 357 };
 358
 359 static int tpm_binary_bios_measurements_open(struct inode *inode,
 360                                              struct file *file)
 361 {
 362         int err;
 363         struct tpm_bios_log *log;
 364         struct seq_file *seq;
 365
 366         log = kzalloc(sizeof(struct tpm_bios_log), GFP_KERNEL);
 367         if (!log)
 368                 return -ENOMEM;
 369
 370         if ((err = read_log(log)))
 371                 goto out_free;
 372
 373         /* now register seq file */
 374         err = seq_open(file, &tpm_binary_b_measurments_seqops);
 375         if (!err) {
 376                 seq = file->private_data;
 377                 seq->private = log;
 378         } else {
 379                 goto out_free;
 380         }
 381
 382 out:
 383         return err;
 384 out_free:
 385         kfree(log->bios_event_log);
 386         kfree(log);
 387         goto out;
 388 }
 389
 390 static const struct file_operations tpm_binary_bios_measurements_ops = {
 391         .open = tpm_binary_bios_measurements_open,
 392         .read = seq_read,
 393         .llseek = seq_lseek,
 394         .release = tpm_bios_measurements_release,
 395 };
 396
 397 static int is_bad(void *p)
 398 {
 399         if (!p)
 400                 return 1;
 401         if (IS_ERR(p) && (PTR_ERR(p) != -ENODEV))
 402                 return 1;
 403         return 0;
 404 }
 405
 406 struct dentry **tpm_bios_log_setup(const char *name)
 407 {
 408         struct dentry **ret = NULL, *tpm_dir, *bin_file, *ascii_file;
 409
 410         tpm_dir = securityfs_create_dir(name, NULL);
 411         if (is_bad(tpm_dir))
 412                 goto out;
 413
 414         bin_file =
 415             securityfs_create_file("binary_bios_measurements",
 416                                    S_IRUSR | S_IRGRP, tpm_dir, NULL,
 417                                    &tpm_binary_bios_measurements_ops);
 418         if (is_bad(bin_file))
 419                 goto out_tpm;
 420
 421         ascii_file =
 422             securityfs_create_file("ascii_bios_measurements",
 423                                    S_IRUSR | S_IRGRP, tpm_dir, NULL,
 424                                    &tpm_ascii_bios_measurements_ops);
 425         if (is_bad(ascii_file))
 426                 goto out_bin;
 427
 428         ret = kmalloc(3 * sizeof(struct dentry *), GFP_KERNEL);
 429         if (!ret)
 430                 goto out_ascii;
 431
 432         ret[0] = ascii_file;
 433         ret[1] = bin_file;
 434         ret[2] = tpm_dir;
 435
 436         return ret;
 437
 438 out_ascii:
 439         securityfs_remove(ascii_file);
 440 out_bin:
 441         securityfs_remove(bin_file);
 442 out_tpm:
 443         securityfs_remove(tpm_dir);
 444 out:
 445         return NULL;
 446 }
 447
 448 void tpm_bios_log_teardown(struct dentry **lst)
 449 {
 450         int i;
 451
 452         for (i = 0; i < 3; i++)
 453                 securityfs_remove(lst[i]);
 454 }