drivers/char/tpm/tpm_eventlog.c

   1 /*
   2  * Copyright (C) 2005, 2012 IBM Corporation
   3  *
   4  * Authors:
   5  *      Kent Yoder <[email protected]>
   6  *      Seiji Munetoh <[email protected]>
   7  *      Stefan Berger <[email protected]>
   8  *      Reiner Sailer <[email protected]>
   9  *      Kylene Hall <[email protected]>
  10  *
  11  * Maintained by: <[email protected]>
  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
  80         /* read over *pos measurements */
  81         for (i = 0; i < *pos; i++) {
  82                 event = addr;
  83
  84                 if ((addr + sizeof(struct tcpa_event)) < limit) {
  85                         if (event->event_type == 0 && event->event_size == 0)
  86                                 return NULL;
  87                         addr += sizeof(struct tcpa_event) + event->event_size;
  88                 }
  89         }
  90
  91         /* now check if current entry is valid */
  92         if ((addr + sizeof(struct tcpa_event)) >= limit)
  93                 return NULL;
  94
  95         event = addr;
  96
  97         if ((event->event_type == 0 && event->event_size == 0) ||
  98             ((addr + sizeof(struct tcpa_event) + event->event_size) >= limit))
  99                 return NULL;
 100
 101         return addr;
 102 }
 103
 104 static void *tpm_bios_measurements_next(struct seq_file *m, void *v,
 105                                         loff_t *pos)
 106 {
 107         struct tcpa_event *event = v;
 108         struct tpm_bios_log *log = m->private;
 109         void *limit = log->bios_event_log_end;
 110
 111         v += sizeof(struct tcpa_event) + event->event_size;
 112
 113         /* now check if current entry is valid */
 114         if ((v + sizeof(struct tcpa_event)) >= limit)
 115                 return NULL;
 116
 117         event = v;
 118
 119         if (event->event_type == 0 && event->event_size == 0)
 120                 return NULL;
 121
 122         if ((event->event_type == 0 && event->event_size == 0) ||
 123             ((v + sizeof(struct tcpa_event) + event->event_size) >= limit))
 124                 return NULL;
 125
 126         (*pos)++;
 127         return v;
 128 }
 129
 130 static void tpm_bios_measurements_stop(struct seq_file *m, void *v)
 131 {
 132 }
 133
 134 static int get_event_name(char *dest, struct tcpa_event *event,
 135                         unsigned char * event_entry)
 136 {
 137         const char *name = "";
 138         /* 41 so there is room for 40 data and 1 nul */
 139         char data[41] = "";
 140         int i, n_len = 0, d_len = 0;
 141         struct tcpa_pc_event *pc_event;
 142
 143         switch(event->event_type) {
 144         case PREBOOT:
 145         case POST_CODE:
 146         case UNUSED:
 147         case NO_ACTION:
 148         case SCRTM_CONTENTS:
 149         case SCRTM_VERSION:
 150         case CPU_MICROCODE:
 151         case PLATFORM_CONFIG_FLAGS:
 152         case TABLE_OF_DEVICES:
 153         case COMPACT_HASH:
 154         case IPL:
 155         case IPL_PARTITION_DATA:
 156         case NONHOST_CODE:
 157         case NONHOST_CONFIG:
 158         case NONHOST_INFO:
 159                 name = tcpa_event_type_strings[event->event_type];
 160                 n_len = strlen(name);
 161                 break;
 162         case SEPARATOR:
 163         case ACTION:
 164                 if (MAX_TEXT_EVENT > event->event_size) {
 165                         name = event_entry;
 166                         n_len = event->event_size;
 167                 }
 168                 break;
 169         case EVENT_TAG:
 170                 pc_event = (struct tcpa_pc_event *)event_entry;
 171
 172                 /* ToDo Row data -> Base64 */
 173
 174                 switch (pc_event->event_id) {
 175                 case SMBIOS:
 176                 case BIS_CERT:
 177                 case CMOS:
 178                 case NVRAM:
 179                 case OPTION_ROM_EXEC:
 180                 case OPTION_ROM_CONFIG:
 181                 case S_CRTM_VERSION:
 182                         name = tcpa_pc_event_id_strings[pc_event->event_id];
 183                         n_len = strlen(name);
 184                         break;
 185                 /* hash data */
 186                 case POST_BIOS_ROM:
 187                 case ESCD:
 188                 case OPTION_ROM_MICROCODE:
 189                 case S_CRTM_CONTENTS:
 190                 case POST_CONTENTS:
 191                         name = tcpa_pc_event_id_strings[pc_event->event_id];
 192                         n_len = strlen(name);
 193                         for (i = 0; i < 20; i++)
 194                                 d_len += sprintf(&data[2*i], "%02x",
 195                                                 pc_event->event_data[i]);
 196                         break;
 197                 default:
 198                         break;
 199                 }
 200         default:
 201                 break;
 202         }
 203
 204         return snprintf(dest, MAX_TEXT_EVENT, "[%.*s%.*s]",
 205                         n_len, name, d_len, data);
 206
 207 }
 208
 209 static int tpm_binary_bios_measurements_show(struct seq_file *m, void *v)
 210 {
 211         struct tcpa_event *event = v;
 212         char *data = v;
 213         int i;
 214
 215         for (i = 0; i < sizeof(struct tcpa_event) + event->event_size; i++)
 216                 seq_putc(m, data[i]);
 217
 218         return 0;
 219 }
 220
 221 static int tpm_bios_measurements_release(struct inode *inode,
 222                                          struct file *file)
 223 {
 224         struct seq_file *seq = file->private_data;
 225         struct tpm_bios_log *log = seq->private;
 226
 227         if (log) {
 228                 kfree(log->bios_event_log);
 229                 kfree(log);
 230         }
 231
 232         return seq_release(inode, file);
 233 }
 234
 235 static int tpm_ascii_bios_measurements_show(struct seq_file *m, void *v)
 236 {
 237         int len = 0;
 238         int i;
 239         char *eventname;
 240         struct tcpa_event *event = v;
 241         unsigned char *event_entry =
 242             (unsigned char *) (v + sizeof(struct tcpa_event));
 243
 244         eventname = kmalloc(MAX_TEXT_EVENT, GFP_KERNEL);
 245         if (!eventname) {
 246                 printk(KERN_ERR "%s: ERROR - No Memory for event name\n ",
 247                        __func__);
 248                 return -EFAULT;
 249         }
 250
 251         seq_printf(m, "%2d ", event->pcr_index);
 252
 253         /* 2nd: SHA1 */
 254         for (i = 0; i < 20; i++)
 255                 seq_printf(m, "%02x", event->pcr_value[i]);
 256
 257         /* 3rd: event type identifier */
 258         seq_printf(m, " %02x", event->event_type);
 259
 260         len += get_event_name(eventname, event, event_entry);
 261
 262         /* 4th: eventname <= max + \'0' delimiter */
 263         seq_printf(m, " %s\n", eventname);
 264
 265         kfree(eventname);
 266         return 0;
 267 }
 268
 269 static const struct seq_operations tpm_ascii_b_measurments_seqops = {
 270         .start = tpm_bios_measurements_start,
 271         .next = tpm_bios_measurements_next,
 272         .stop = tpm_bios_measurements_stop,
 273         .show = tpm_ascii_bios_measurements_show,
 274 };
 275
 276 static const struct seq_operations tpm_binary_b_measurments_seqops = {
 277         .start = tpm_bios_measurements_start,
 278         .next = tpm_bios_measurements_next,
 279         .stop = tpm_bios_measurements_stop,
 280         .show = tpm_binary_bios_measurements_show,
 281 };
 282
 283 static int tpm_ascii_bios_measurements_open(struct inode *inode,
 284                                             struct file *file)
 285 {
 286         int err;
 287         struct tpm_bios_log *log;
 288         struct seq_file *seq;
 289
 290         log = kzalloc(sizeof(struct tpm_bios_log), GFP_KERNEL);
 291         if (!log)
 292                 return -ENOMEM;
 293
 294         if ((err = read_log(log)))
 295                 goto out_free;
 296
 297         /* now register seq file */
 298         err = seq_open(file, &tpm_ascii_b_measurments_seqops);
 299         if (!err) {
 300                 seq = file->private_data;
 301                 seq->private = log;
 302         } else {
 303                 goto out_free;
 304         }
 305
 306 out:
 307         return err;
 308 out_free:
 309         kfree(log->bios_event_log);
 310         kfree(log);
 311         goto out;
 312 }
 313
 314 static const struct file_operations tpm_ascii_bios_measurements_ops = {
 315         .open = tpm_ascii_bios_measurements_open,
 316         .read = seq_read,
 317         .llseek = seq_lseek,
 318         .release = tpm_bios_measurements_release,
 319 };
 320
 321 static int tpm_binary_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_binary_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_binary_bios_measurements_ops = {
 353         .open = tpm_binary_bios_measurements_open,
 354         .read = seq_read,
 355         .llseek = seq_lseek,
 356         .release = tpm_bios_measurements_release,
 357 };
 358
 359 static int is_bad(void *p)
 360 {
 361         if (!p)
 362                 return 1;
 363         if (IS_ERR(p) && (PTR_ERR(p) != -ENODEV))
 364                 return 1;
 365         return 0;
 366 }
 367
 368 struct dentry **tpm_bios_log_setup(char *name)
 369 {
 370         struct dentry **ret = NULL, *tpm_dir, *bin_file, *ascii_file;
 371
 372         tpm_dir = securityfs_create_dir(name, NULL);
 373         if (is_bad(tpm_dir))
 374                 goto out;
 375
 376         bin_file =
 377             securityfs_create_file("binary_bios_measurements",
 378                                    S_IRUSR | S_IRGRP, tpm_dir, NULL,
 379                                    &tpm_binary_bios_measurements_ops);
 380         if (is_bad(bin_file))
 381                 goto out_tpm;
 382
 383         ascii_file =
 384             securityfs_create_file("ascii_bios_measurements",
 385                                    S_IRUSR | S_IRGRP, tpm_dir, NULL,
 386                                    &tpm_ascii_bios_measurements_ops);
 387         if (is_bad(ascii_file))
 388                 goto out_bin;
 389
 390         ret = kmalloc(3 * sizeof(struct dentry *), GFP_KERNEL);
 391         if (!ret)
 392                 goto out_ascii;
 393
 394         ret[0] = ascii_file;
 395         ret[1] = bin_file;
 396         ret[2] = tpm_dir;
 397
 398         return ret;
 399
 400 out_ascii:
 401         securityfs_remove(ascii_file);
 402 out_bin:
 403         securityfs_remove(bin_file);
 404 out_tpm:
 405         securityfs_remove(tpm_dir);
 406 out:
 407         return NULL;
 408 }
 409 EXPORT_SYMBOL_GPL(tpm_bios_log_setup);
 410
 411 void tpm_bios_log_teardown(struct dentry **lst)
 412 {
 413         int i;
 414
 415         for (i = 0; i < 3; i++)
 416                 securityfs_remove(lst[i]);
 417 }
 418 EXPORT_SYMBOL_GPL(tpm_bios_log_teardown);
 419 MODULE_LICENSE("GPL");