apps/plugins/keybox.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2008 Nils Wallménius
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  18  * KIND, either express or implied.
  19  *
  20  ****************************************************************************/
  21 #include "plugin.h"
  22 #include "lib/md5.h"
  23 PLUGIN_HEADER
  24
  25 #define KEYBOX_FILE PLUGIN_APPS_DIR "/keybox.dat"
  26 #define BLOCK_SIZE 8
  27 #define MAX_ENTRIES 12*BLOCK_SIZE /* keep this a multiple of BLOCK_SIZE */
  28 #define FIELD_LEN 32 /* should be enough for anyone ;) */
  29
  30 /* The header begins with the unencrypted salt (4 bytes) padded with 4 bytes of
  31    zeroes. After that comes the encrypted hash of the master password (16 bytes) */
  32
  33
  34 #define HEADER_LEN 24
  35
  36 enum
  37 {
  38     FILE_OPEN_ERROR = -1
  39 };
  40
  41 struct pw_entry
  42 {
  43     bool used;
  44     char title[FIELD_LEN];
  45     char name[FIELD_LEN];
  46     char password[FIELD_LEN];
  47     struct pw_entry *next;
  48 };
  49
  50 struct pw_list
  51 {
  52     struct pw_entry first; /* always points to the first element in the list */
  53     struct pw_entry entries[MAX_ENTRIES];
  54     int num_entries;
  55 } pw_list;
  56
  57 /* use this to access hashes in different ways, not byte order
  58    independent but does it matter? */
  59 union hash
  60 {
  61     uint8_t bytes[16];
  62     uint32_t words[4];
  63 };
  64
  65 static char buffer[sizeof(struct pw_entry)*MAX_ENTRIES];
  66 static int bytes_read = 0; /* bytes read into the buffer */
  67 static struct gui_synclist kb_list;
  68 static union hash key;
  69 static char master_pw[FIELD_LEN];
  70 static uint32_t salt;
  71 static union hash pwhash;
  72 static bool data_changed = false;
  73
  74 static void encrypt_buffer(char *buf, size_t size, uint32_t *key);
  75 static void decrypt_buffer(char *buf, size_t size, uint32_t *key);
  76
  77 /* the following two functions are the reference TEA implementation by
  78    David Wheeler and Roger Needham taken from
  79    http://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm */
  80
  81 static void encrypt(uint32_t* v, uint32_t* k)
  82 {
  83     uint32_t v0=v[0], v1=v[1], sum=0, i;           /* set up */
  84     static const uint32_t delta=0x9e3779b9;        /* a key schedule constant */
  85     uint32_t k0=k[0], k1=k[1], k2=k[2], k3=k[3];   /* cache key */
  86     for (i=0; i < 32; i++) {                            /* basic cycle start */
  87         sum += delta;
  88         v0 += ((v1<<4) + k0) ^ (v1 + sum) ^ ((v1>>5) + k1);
  89         v1 += ((v0<<4) + k2) ^ (v0 + sum) ^ ((v0>>5) + k3);  /* end cycle */
  90     }
  91     v[0]=v0; v[1]=v1;
  92 }
  93
  94 static void decrypt(uint32_t* v, uint32_t* k)
  95 {
  96     uint32_t v0=v[0], v1=v[1], sum=0xC6EF3720, i;  /* set up */
  97     static const uint32_t delta=0x9e3779b9;        /* a key schedule constant */
  98     uint32_t k0=k[0], k1=k[1], k2=k[2], k3=k[3];   /* cache key */
  99     for (i=0; i<32; i++) {                              /* basic cycle start */
 100         v1 -= ((v0<<4) + k2) ^ (v0 + sum) ^ ((v0>>5) + k3);
 101         v0 -= ((v1<<4) + k0) ^ (v1 + sum) ^ ((v1>>5) + k1);
 102         sum -= delta;                                   /* end cycle */
 103     }
 104     v[0]=v0; v[1]=v1;
 105 }
 106
 107 static int context_item_cb(int action, const struct menu_item_ex *this_item)
 108 {
 109     if (action == ACTION_REQUEST_MENUITEM
 110         && pw_list.num_entries == 0
 111         && ((intptr_t)this_item) != 0)
 112     {
 113         return ACTION_EXIT_MENUITEM;
 114     }
 115     return action;
 116 }
 117
 118 MENUITEM_STRINGLIST(context_m, "Context menu", context_item_cb,
 119                     "Add entry",
 120                     "Edit title", "Edit user name", "Edit password",
 121                     "Delete entry")
 122
 123 static char * kb_list_cb(int selected_item, void *data,
 124                          char *buffer, size_t buffer_len)
 125 {
 126     (void)data;
 127     int i;
 128     struct pw_entry *entry = pw_list.first.next;
 129     for (i = 0; i < selected_item; i++)
 130     {
 131         if (entry)
 132             entry = entry->next;
 133     }
 134     if (!entry)
 135         return NULL;
 136
 137     rb->snprintf(buffer, buffer_len, "%s", entry->title);
 138
 139     return buffer;
 140 }
 141
 142 static void init_ll(void)
 143 {
 144     pw_list.first.next = &pw_list.entries[0];
 145     pw_list.entries[0].next = NULL;
 146     pw_list.num_entries = 0;
 147 }
 148
 149 static void delete_entry(int selected_item)
 150 {
 151     int i;
 152     struct pw_entry *entry = &pw_list.first;
 153     struct pw_entry *entry2;
 154
 155     /* find the entry before the one to delete */
 156     for (i = 0; i < selected_item; i++)
 157     {
 158         if (entry->next)
 159             entry = entry->next;
 160     }
 161     entry2 = entry->next;
 162     if (!entry2)
 163         return;
 164
 165     entry->next = entry2->next;
 166
 167     entry2->used = false;
 168     entry2->name[0] = '\0';
 169     entry2->password[0] = '\0';
 170     entry2->next = NULL;
 171
 172     rb->gui_synclist_set_nb_items(&kb_list, --pw_list.num_entries);
 173     data_changed = true;
 174 }
 175
 176 static void add_entry(int selected_item)
 177 {
 178     int i, j;
 179     struct pw_entry *entry = pw_list.first.next;
 180     for (i = 0; i < MAX_ENTRIES && pw_list.entries[i].used; i++)
 181         ;
 182
 183     if (pw_list.entries[i].used)
 184     {
 185         rb->splash(HZ, "Password list full");
 186         return;
 187     }
 188
 189     rb->splash(HZ, "Enter title");
 190     pw_list.entries[i].title[0] = '\0';
 191     if (rb->kbd_input(pw_list.entries[i].title, FIELD_LEN))
 192         return;
 193
 194     rb->splash(HZ, "Enter name");
 195     pw_list.entries[i].name[0] = '\0';
 196     if (rb->kbd_input(pw_list.entries[i].name, FIELD_LEN))
 197     {
 198         pw_list.entries[i].title[0] = '\0';
 199         return;
 200     }
 201
 202     rb->splash(HZ, "Enter password");
 203     pw_list.entries[i].password[0] = '\0';
 204     if (rb->kbd_input(pw_list.entries[i].password, FIELD_LEN))
 205     {
 206         pw_list.entries[i].title[0] = '\0';
 207         pw_list.entries[i].name[0] = '\0';
 208         return;
 209     }
 210
 211     for (j = 0; j < selected_item; j++)
 212     {
 213         if (entry->next)
 214             entry = entry->next;
 215     }
 216
 217     rb->gui_synclist_set_nb_items(&kb_list, ++pw_list.num_entries);
 218
 219     pw_list.entries[i].used = true;
 220     pw_list.entries[i].next = entry->next;
 221
 222     entry->next = &pw_list.entries[i];
 223
 224     if (entry->next == entry)
 225         entry->next = NULL;
 226
 227     data_changed = true;
 228 }
 229
 230 static void edit_title(int selected_item)
 231 {
 232     int i;
 233     struct pw_entry *entry = pw_list.first.next;
 234     for (i = 0; i < selected_item; i++)
 235     {
 236         if (entry->next)
 237             entry = entry->next;
 238     }
 239     if (rb->kbd_input(entry->title, FIELD_LEN) == 0)
 240         data_changed = true;
 241 }
 242
 243 static void edit_name(int selected_item)
 244 {
 245     int i;
 246     struct pw_entry *entry = pw_list.first.next;
 247     for (i = 0; i < selected_item; i++)
 248     {
 249         if (entry->next)
 250             entry = entry->next;
 251     }
 252     if (rb->kbd_input(entry->name, FIELD_LEN) == 0)
 253         data_changed = true;
 254 }
 255
 256 static void edit_pw(int selected_item)
 257 {
 258     int i;
 259     struct pw_entry *entry = pw_list.first.next;
 260     for (i = 0; i < selected_item; i++)
 261     {
 262         if (entry->next)
 263             entry = entry->next;
 264     }
 265     if (rb->kbd_input(entry->password, FIELD_LEN) == 0)
 266         data_changed = true;
 267 }
 268
 269 static void context_menu(int selected_item)
 270 {
 271     int selection, result;
 272     bool exit = false;
 273
 274     do {
 275         result = rb->do_menu(&context_m, &selection, NULL, false);
 276         switch (result) {
 277         case 0:
 278             add_entry(selected_item);
 279             return;
 280         case 1:
 281             edit_title(selected_item);
 282             return;
 283         case 2:
 284             edit_name(selected_item);
 285             return;
 286         case 3:
 287             edit_pw(selected_item);
 288             return;
 289         case 4:
 290             delete_entry(selected_item);
 291             return;
 292         default:
 293             exit = true;
 294             break;
 295         }
 296         rb->yield();
 297     } while (!exit);
 298 }
 299
 300 static void splash_pw(int selected_item)
 301 {
 302     int i;
 303     struct pw_entry *entry = pw_list.first.next;
 304
 305     for (i = 0; i < selected_item; i++)
 306     {
 307         if (entry->next)
 308             entry = entry->next;
 309     }
 310     if (entry->name != '\0')
 311         rb->splashf(0, "%s  %s", entry->name, entry->password);
 312     else
 313         rb->splashf(0, "%s", entry->password);
 314     rb->get_action(CONTEXT_STD, TIMEOUT_BLOCK);
 315 }
 316
 317 static void hash_pw(union hash *out)
 318 {
 319     int i;
 320     struct md5_s pw_md5;
 321
 322     InitMD5(&pw_md5);
 323     AddMD5(&pw_md5, master_pw, rb->strlen(master_pw));
 324     EndMD5(&pw_md5);
 325
 326     for (i = 0; i < 4; i++)
 327         out->words[i] = htole32(pw_md5.p_digest[i]);
 328 }
 329
 330 static void make_key(void)
 331 {
 332     int i;
 333     char buf[sizeof(master_pw) + sizeof(salt) + 1];
 334     struct md5_s key_md5;
 335     size_t len = rb->strlen(master_pw);
 336
 337     rb->strncpy(buf, master_pw, sizeof(buf));
 338
 339     rb->memcpy(&buf[len], &salt, sizeof(salt));
 340
 341     InitMD5(&key_md5);
 342     AddMD5(&key_md5, buf, rb->strlen(buf));
 343     EndMD5(&key_md5);
 344
 345     for (i = 0; i < 4; i++)
 346         key.words[i] = key_md5.p_digest[i];
 347 }
 348
 349 static void decrypt_buffer(char *buf, size_t size, uint32_t *key)
 350 {
 351     unsigned int i;
 352     uint32_t block[2];
 353
 354     for (i = 0; i < size/BLOCK_SIZE; i++)
 355     {
 356         rb->memcpy(&block[0], &buf[i*BLOCK_SIZE], sizeof(block));
 357
 358         block[0] = letoh32(block[0]);
 359         block[1] = letoh32(block[1]);
 360
 361         decrypt(&block[0], key);
 362
 363         /* byte swap one block */
 364         block[0] = letoh32(block[0]);
 365         block[1] = letoh32(block[1]);
 366
 367         rb->memcpy(&buf[i*BLOCK_SIZE], &block[0], sizeof(block));
 368     }
 369 }
 370
 371 static void encrypt_buffer(char *buf, size_t size, uint32_t *key)
 372 {
 373     unsigned int i;
 374     uint32_t block[2];
 375
 376     for (i = 0; i < size/BLOCK_SIZE; i++)
 377     {
 378         rb->memcpy(&block[0], &buf[i*BLOCK_SIZE], sizeof(block));
 379
 380         /* byte swap one block */
 381         block[0] = htole32(block[0]);
 382         block[1] = htole32(block[1]);
 383
 384         encrypt(&block[0], key);
 385
 386         block[0] = htole32(block[0]);
 387         block[1] = htole32(block[1]);
 388
 389         rb->memcpy(&buf[i*BLOCK_SIZE], &block[0], sizeof(block));
 390     }
 391 }
 392
 393 static int parse_buffer(void)
 394 {
 395     int i;
 396     int len;
 397     struct pw_entry *entry = pw_list.first.next;
 398     char *start, *end;
 399     start = &buffer[HEADER_LEN];
 400
 401     rb->memcpy(&salt, &buffer[0], sizeof(salt));
 402     make_key();
 403
 404     decrypt_buffer(&buffer[8], bytes_read - 8, &key.words[0]);
 405
 406     if (rb->memcmp(&buffer[8], &pwhash, sizeof(union hash)))
 407     {
 408         rb->splash(HZ*2, "Wrong password");
 409         return -1;
 410     }
 411
 412     for (i = 0; i < MAX_ENTRIES; i++)
 413     {
 414         end = rb->strchr(start, '\0'); /* find eol */
 415         len = end - &buffer[HEADER_LEN];
 416         if ((len > bytes_read + HEADER_LEN) || start == end)
 417         {
 418             break;
 419         }
 420
 421         rb->strncpy(entry->title, start, FIELD_LEN);
 422         start = end + 1;
 423
 424         end = rb->strchr(start, '\0'); /* find eol */
 425         len = end - &buffer[HEADER_LEN];
 426         if (len > bytes_read + HEADER_LEN)
 427         {
 428             break;
 429         }
 430
 431         rb->strncpy(entry->name, start, FIELD_LEN);
 432         start = end + 1;
 433
 434         end = rb->strchr(start, '\0'); /* find eol */
 435         len = end - &buffer[HEADER_LEN];
 436         if (len > bytes_read + HEADER_LEN)
 437         {
 438             break;
 439         }
 440         rb->strncpy(entry->password, start, FIELD_LEN);
 441         start = end + 1;
 442         entry->used = true;
 443         if (i + 1 < MAX_ENTRIES - 1)
 444         {
 445             entry->next = &pw_list.entries[i+1];
 446             entry = entry->next;
 447         }
 448         else
 449         {
 450             break;
 451         }
 452     }
 453     entry->next = NULL;
 454     pw_list.num_entries = i;
 455     rb->gui_synclist_set_nb_items(&kb_list, pw_list.num_entries);
 456     return 0;
 457 }
 458
 459 static void write_output(int fd)
 460 {
 461     size_t bytes_written;
 462     int i;
 463     size_t len, size;
 464     char *p = &buffer[HEADER_LEN]; /* reserve space for salt + hash */
 465
 466     rb->memcpy(&buffer[8], &pwhash, sizeof(union hash));
 467     struct pw_entry *entry = pw_list.first.next;
 468
 469     for (i = 0; i < pw_list.num_entries; i++)
 470     {
 471         len = rb->strlen(entry->title);
 472         rb->strncpy(p, entry->title, len+1);
 473         p += len+1;
 474         len = rb->strlen(entry->name);
 475         rb->strncpy(p, entry->name, len+1);
 476         p += len+1;
 477         len = rb->strlen(entry->password);
 478         rb->strncpy(p, entry->password, len+1);
 479         p += len+1;
 480         if (entry->next)
 481             entry = entry->next;
 482     }
 483     *p++ = '\0'; /* mark the end of the list */
 484
 485     /* round up to a number divisible by BLOCK_SIZE */
 486     size = ((p - buffer + BLOCK_SIZE - 1) / BLOCK_SIZE) * BLOCK_SIZE;
 487
 488     salt = rb->rand();
 489     make_key();
 490
 491     encrypt_buffer(&buffer[8], size, &key.words[0]);
 492     rb->memcpy(&buffer[0], &salt, sizeof(salt));
 493
 494     bytes_written = rb->write(fd, &buffer, size);
 495 }
 496
 497 static int enter_pw(char *pw_buf, size_t buflen, bool new_pw)
 498 {
 499     char buf[2][sizeof(master_pw)];
 500     rb->memset(buf, 0, sizeof(buf));
 501     rb->memset(master_pw, 0, sizeof(master_pw));
 502
 503     if (new_pw)
 504     {
 505         rb->splash(HZ, "Enter new master password");
 506         if (rb->kbd_input(buf[0], sizeof(buf[0])))
 507             return -1;
 508
 509         rb->splash(HZ, "Confirm master password");
 510         if (rb->kbd_input(buf[1], sizeof(buf[1])))
 511             return -1;
 512
 513         if (rb->strcmp(buf[0], buf[1]))
 514         {
 515             rb->splash(HZ, "Password mismatch");
 516             return -1;
 517         }
 518         else
 519         {
 520             rb->strncpy(pw_buf, buf[0], buflen);
 521             hash_pw(&pwhash);
 522             return 0;
 523         }
 524     }
 525
 526     rb->splash(HZ, "Enter master password");
 527     if (rb->kbd_input(pw_buf, buflen))
 528         return -1;
 529     hash_pw(&pwhash);
 530     return 0;
 531 }
 532
 533 static int keybox(void)
 534 {
 535     int button, fd;
 536     bool new_file = !rb->file_exists(KEYBOX_FILE);
 537     bool done = false;
 538
 539     if (enter_pw(master_pw, sizeof (master_pw), new_file))
 540         return 0;
 541
 542     /* Read the existing file */
 543     if (!new_file)
 544     {
 545         fd = rb->open(KEYBOX_FILE, O_RDONLY);
 546         if (fd < 0)
 547             return FILE_OPEN_ERROR;
 548         bytes_read = rb->read(fd, &buffer, sizeof(buffer));
 549
 550         if (parse_buffer())
 551             return 0;
 552
 553         rb->close(fd);
 554     }
 555
 556     while (!done)
 557     {
 558         rb->gui_synclist_draw(&kb_list);
 559         button = rb->get_action(CONTEXT_LIST, TIMEOUT_BLOCK);
 560         if (rb->gui_synclist_do_button(&kb_list, &button, LIST_WRAP_ON))
 561             continue;
 562
 563         switch (button)
 564         {
 565             case ACTION_STD_OK:
 566                 splash_pw(rb->gui_synclist_get_sel_pos(&kb_list));
 567                 break;
 568             case ACTION_STD_CONTEXT:
 569                 context_menu(rb->gui_synclist_get_sel_pos(&kb_list));
 570                 break;
 571             case ACTION_STD_CANCEL:
 572                 done = true;
 573                 break;
 574         }
 575         rb->yield();
 576     }
 577
 578     if (data_changed)
 579     {
 580         fd = rb->open(KEYBOX_FILE, O_WRONLY | O_CREAT | O_TRUNC);
 581         if (fd < 0)
 582             return FILE_OPEN_ERROR;
 583         write_output(fd);
 584         rb->close(fd);
 585     }
 586
 587     return 0;
 588 }
 589
 590 static void reset(void)
 591 {
 592     static const char *message_lines[]=
 593         {"Do you really want", "to reset keybox?"};
 594     static const char *yes_lines[]=
 595         {"Keybox reset."};
 596     static const struct text_message message={message_lines, 2};
 597     static const struct text_message yes_message={yes_lines, 1};
 598
 599     if(rb->gui_syncyesno_run(&message, &yes_message, NULL) == YESNO_YES)
 600     {
 601         rb->remove(KEYBOX_FILE);
 602         rb->memset(&buffer, 0, sizeof(buffer));
 603         rb->memset(&pw_list, 0, sizeof(pw_list));
 604         init_ll();
 605     }
 606 }
 607
 608 static int main_menu(void)
 609 {
 610     int selection, result, ret;
 611     bool exit = false;
 612
 613     MENUITEM_STRINGLIST(menu,"Keybox", NULL, "Enter Keybox",
 614                         "Reset Keybox", "Exit");
 615
 616     do {
 617         result = rb->do_menu(&menu, &selection, NULL, false);
 618         switch (result) {
 619         case 0:
 620             ret = keybox();
 621             if (ret)
 622                 return ret;
 623             break;
 624         case 1:
 625             reset();
 626             break;
 627         case 2:
 628             exit = true;
 629             break;
 630         }
 631         rb->yield();
 632     } while (!exit);
 633
 634     return 0;
 635 }
 636
 637 enum plugin_status plugin_start(const void *parameter)
 638 {
 639     (void)parameter;
 640     int ret;
 641
 642     rb->gui_synclist_init(&kb_list, &kb_list_cb, NULL, false, 1, NULL);
 643
 644     rb->gui_synclist_set_title(&kb_list, "Keybox", NOICON);
 645     rb->gui_synclist_set_icon_callback(&kb_list, NULL);
 646     rb->gui_synclist_set_nb_items(&kb_list, 0);
 647     rb->gui_synclist_limit_scroll(&kb_list, false);
 648     rb->gui_synclist_select_item(&kb_list, 0);
 649
 650     init_ll();
 651     ret = main_menu();
 652
 653     switch (ret)
 654     {
 655         case FILE_OPEN_ERROR:
 656             rb->splash(HZ*2, "Error opening file");
 657             return PLUGIN_ERROR;
 658     }
 659
 660     return PLUGIN_OK;
 661 }
 662