ldid.cpp

   1 /* JocStrap - Java/Objective-C Bootstrap
   2  * Copyright (C) 2007  Jay Freeman (saurik)
   3 */
   4
   5 /*
   6  *        Redistribution and use in source and binary
   7  * forms, with or without modification, are permitted
   8  * provided that the following conditions are met:
   9  *
  10  * 1. Redistributions of source code must retain the
  11  *    above copyright notice, this list of conditions
  12  *    and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the
  14  *    above copyright notice, this list of conditions
  15  *    and the following disclaimer in the documentation
  16  *    and/or other materials provided with the
  17  *    distribution.
  18  * 3. The name of the author may not be used to endorse
  19  *    or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS''
  23  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
  24  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
  27  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  28  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  29  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  30  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  32  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
  33  * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  34  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  35  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36 */
  37
  38 #include "minimal/stdlib.h"
  39 #include "minimal/string.h"
  40 #include "minimal/mapping.h"
  41
  42 #include "sha1.h"
  43
  44 #include <cstring>
  45 #include <string>
  46 #include <vector>
  47
  48 #include <sys/wait.h>
  49 #include <sys/types.h>
  50 #include <sys/stat.h>
  51
  52 struct fat_header {
  53     uint32_t magic;
  54     uint32_t nfat_arch;
  55 } _packed;
  56
  57 #define FAT_MAGIC 0xcafebabe
  58 #define FAT_CIGAM 0xbebafeca
  59
  60 struct fat_arch {
  61     uint32_t cputype;
  62     uint32_t cpusubtype;
  63     uint32_t offset;
  64     uint32_t size;
  65     uint32_t align;
  66 } _packed;
  67
  68 struct mach_header {
  69     uint32_t magic;
  70     uint32_t cputype;
  71     uint32_t cpusubtype;
  72     uint32_t filetype;
  73     uint32_t ncmds;
  74     uint32_t sizeofcmds;
  75     uint32_t flags;
  76 } _packed;
  77
  78 #define MH_MAGIC 0xfeedface
  79 #define MH_CIGAM 0xcefaedfe
  80
  81 #define MH_EXECUTE    0x2
  82 #define MH_DYLIB      0x6
  83 #define MH_BUNDLE     0x8
  84 #define MH_DYLIB_STUB 0x9
  85
  86 struct load_command {
  87     uint32_t cmd;
  88     uint32_t cmdsize;
  89 } _packed;
  90
  91 #define LC_REQ_DYLD  0x80000000
  92
  93 #define LC_LOAD_DYLIB      0x0c
  94 #define LC_ID_DYLIB        0x0d
  95 #define LC_UUID            0x1b
  96 #define LC_CODE_SIGNATURE  0x1d
  97 #define LC_REEXPORT_DYLIB (0x1f | LC_REQ_DYLD)
  98
  99 struct dylib {
 100     uint32_t name;
 101     uint32_t timestamp;
 102     uint32_t current_version;
 103     uint32_t compatibility_version;
 104 } _packed;
 105
 106 struct dylib_command {
 107     uint32_t cmd;
 108     uint32_t cmdsize;
 109     struct dylib dylib;
 110 } _packed;
 111
 112 struct uuid_command {
 113     uint32_t cmd;
 114     uint32_t cmdsize;
 115     uint8_t uuid[16];
 116 } _packed;
 117
 118 struct linkedit_data_command {
 119     uint32_t cmd;
 120     uint32_t cmdsize;
 121     uint32_t dataoff;
 122     uint32_t datasize;
 123 } _packed;
 124
 125 uint16_t Swap_(uint16_t value) {
 126     return
 127         ((value >>  8) & 0x00ff) |
 128         ((value <<  8) & 0xff00);
 129 }
 130
 131 uint32_t Swap_(uint32_t value) {
 132     value = ((value >>  8) & 0x00ff00ff) |
 133             ((value <<  8) & 0xff00ff00);
 134     value = ((value >> 16) & 0x0000ffff) |
 135             ((value << 16) & 0xffff0000);
 136     return value;
 137 }
 138
 139 int16_t Swap_(int16_t value) {
 140     return Swap_(static_cast<uint16_t>(value));
 141 }
 142
 143 int32_t Swap_(int32_t value) {
 144     return Swap_(static_cast<uint32_t>(value));
 145 }
 146
 147 uint16_t Swap(uint16_t value) {
 148     return true ? Swap_(value) : value;
 149 }
 150
 151 uint32_t Swap(uint32_t value) {
 152     return true ? Swap_(value) : value;
 153 }
 154
 155 int16_t Swap(int16_t value) {
 156     return Swap(static_cast<uint16_t>(value));
 157 }
 158
 159 int32_t Swap(int32_t value) {
 160     return Swap(static_cast<uint32_t>(value));
 161 }
 162
 163 class Framework {
 164   private:
 165     void *base_;
 166     size_t size_;
 167     mach_header *mach_header_;
 168     bool swapped_;
 169
 170   public:
 171     uint16_t Swap(uint16_t value) const {
 172         return swapped_ ? Swap_(value) : value;
 173     }
 174
 175     uint32_t Swap(uint32_t value) const {
 176         return swapped_ ? Swap_(value) : value;
 177     }
 178
 179     int16_t Swap(int16_t value) const {
 180         return Swap(static_cast<uint16_t>(value));
 181     }
 182
 183     int32_t Swap(int32_t value) const {
 184         return Swap(static_cast<uint32_t>(value));
 185     }
 186
 187     Framework(const char *framework_path) :
 188         swapped_(false)
 189     {
 190         base_ = map(framework_path, 0, _not(size_t), &size_, false);
 191         fat_header *fat_header = reinterpret_cast<struct fat_header *>(base_);
 192
 193         if (Swap(fat_header->magic) == FAT_CIGAM) {
 194             swapped_ = !swapped_;
 195             goto fat;
 196         } else if (Swap(fat_header->magic) != FAT_MAGIC)
 197             mach_header_ = (mach_header *) base_;
 198         else fat: {
 199             size_t fat_narch = Swap(fat_header->nfat_arch);
 200             fat_arch *fat_arch = reinterpret_cast<struct fat_arch *>(fat_header + 1);
 201             size_t arch;
 202             for (arch = 0; arch != fat_narch; ++arch) {
 203                 uint32_t arch_offset = Swap(fat_arch->offset);
 204                 mach_header_ = (mach_header *) ((uint8_t *) base_ + arch_offset);
 205                 goto found;
 206                 ++fat_arch;
 207             }
 208
 209             _assert(false);
 210         }
 211
 212       found:
 213         if (Swap(mach_header_->magic) == MH_CIGAM)
 214             swapped_ = !swapped_;
 215         else _assert(Swap(mach_header_->magic) == MH_MAGIC);
 216
 217         _assert(
 218             Swap(mach_header_->filetype) == MH_EXECUTE ||
 219             Swap(mach_header_->filetype) == MH_DYLIB ||
 220             Swap(mach_header_->filetype) == MH_BUNDLE
 221         );
 222     }
 223
 224     struct mach_header *operator ->() const {
 225         return mach_header_;
 226     }
 227
 228     void *GetBase() {
 229         return base_;
 230     }
 231
 232     size_t GetSize() {
 233         return size_;
 234     }
 235
 236     std::vector<struct load_command *> GetLoadCommands() {
 237         std::vector<struct load_command *> load_commands;
 238
 239         struct load_command *load_command = reinterpret_cast<struct load_command *>(mach_header_ + 1);
 240         for (uint32_t cmd = 0; cmd != Swap(mach_header_->ncmds); ++cmd) {
 241             load_commands.push_back(load_command);
 242             load_command = (struct load_command *) ((uint8_t *) load_command + Swap(load_command->cmdsize));
 243         }
 244
 245         return load_commands;
 246     }
 247 };
 248
 249 #define CSMAGIC_CODEDIRECTORY      0xfade0c02
 250 #define CSMAGIC_EMBEDDED_SIGNATURE 0xfade0cc0
 251 #define CSMAGIC_ENTITLEMENTS       0xfade7171
 252
 253 #define CSSLOT_CODEDIRECTORY 0
 254 #define CSSLOT_REQUIREMENTS  2
 255 #define CSSLOT_ENTITLEMENTS  5
 256
 257 struct BlobIndex {
 258     uint32_t type;
 259     uint32_t offset;
 260 } _packed;
 261
 262 struct Blob {
 263     uint32_t magic;
 264     uint32_t length;
 265 } _packed;
 266
 267 struct SuperBlob {
 268     struct Blob blob;
 269     uint32_t count;
 270     struct BlobIndex index[];
 271 } _packed;
 272
 273 struct CodeDirectory {
 274     struct Blob blob;
 275     uint32_t version;
 276     uint32_t flags;
 277     uint32_t hashOffset;
 278     uint32_t identOffset;
 279     uint32_t nSpecialSlots;
 280     uint32_t nCodeSlots;
 281     uint32_t codeLimit;
 282     uint8_t hashSize;
 283     uint8_t hashType;
 284     uint8_t spare1;
 285     uint8_t pageSize;
 286     uint32_t spare2;
 287 } _packed;
 288
 289 extern "C" uint32_t hash(uint8_t *k, uint32_t length, uint32_t initval);
 290
 291 #define CODESIGN_ALLOCATE "arm-apple-darwin9-codesign_allocate"
 292
 293 void sha1(uint8_t *hash, uint8_t *data, size_t size) {
 294     SHA1Context context;
 295     SHA1Reset(&context);
 296     SHA1Input(&context, data, size);
 297     SHA1Result(&context, hash);
 298 }
 299
 300 int main(int argc, const char *argv[]) {
 301     bool flag_R(false);
 302     bool flag_t(false);
 303     bool flag_p(false);
 304     bool flag_u(false);
 305
 306     bool flag_T(false);
 307
 308     bool flag_S(false);
 309     bool flag_s(false);
 310
 311     bool timeh(false);
 312     uint32_t timev(0);
 313
 314     const void *xmld(NULL);
 315     size_t xmls(0);
 316
 317     std::vector<std::string> files;
 318
 319     if (argc == 1) {
 320         fprintf(stderr, "usage: %s -S[entitlements.xml] <binary>\n", argv[0]);
 321         fprintf(stderr, "   %s -S cat\n", argv[0]);
 322         fprintf(stderr, "   %s -Stfp.xml gdb\n", argv[0]);
 323         exit(0);
 324     }
 325
 326     for (int argi(1); argi != argc; ++argi)
 327         if (argv[argi][0] != '-')
 328             files.push_back(argv[argi]);
 329         else switch (argv[argi][1]) {
 330             case 'R': flag_R = true; break;
 331             case 't': flag_t = true; break;
 332             case 'u': flag_u = true; break;
 333             case 'p': flag_p = true; break;
 334
 335             case 's':
 336                 _assert(!flag_S);
 337                 flag_s = true;
 338             break;
 339
 340             case 'S':
 341                 _assert(!flag_s);
 342                 flag_S = true;
 343                 if (argv[argi][2] != '\0') {
 344                     const char *xml = argv[argi] + 2;
 345                     xmld = map(xml, 0, _not(size_t), &xmls, true);
 346                 }
 347             break;
 348
 349             case 'T': {
 350                 flag_T = true;
 351                 if (argv[argi][2] == '-')
 352                     timeh = true;
 353                 else {
 354                     char *arge;
 355                     timev = strtoul(argv[argi] + 2, &arge, 0);
 356                     _assert(arge == argv[argi] + strlen(argv[argi]));
 357                 }
 358             } break;
 359
 360             default:
 361                 goto usage;
 362             break;
 363         }
 364
 365     if (files.empty()) usage: {
 366         exit(0);
 367     }
 368
 369     size_t filei(0), filee(0);
 370     _foreach (file, files) try {
 371         const char *path(file->c_str());
 372         const char *base = strrchr(path, '/');
 373         char *temp(NULL), *dir;
 374         mode_t mode = 0;
 375
 376         if (base != NULL)
 377             dir = strndup_(path, base++ - path + 1);
 378         else {
 379             dir = strdup("");
 380             base = path;
 381         }
 382
 383         if (flag_S) {
 384             asprintf(&temp, "%s.%s.cs", dir, base);
 385             const char *allocate = getenv("CODESIGN_ALLOCATE");
 386             if (allocate == NULL)
 387                 allocate = "codesign_allocate";
 388
 389             size_t size = _not(size_t);
 390             const char *arch; {
 391                 Framework framework(path);
 392                 _foreach (load_command, framework.GetLoadCommands()) {
 393                     uint32_t cmd(framework.Swap((*load_command)->cmd));
 394                     if (cmd == LC_CODE_SIGNATURE) {
 395                         struct linkedit_data_command *signature = reinterpret_cast<struct linkedit_data_command *>(*load_command);
 396                         size = framework.Swap(signature->dataoff);
 397                         _assert(size < framework.GetSize());
 398                         break;
 399                     }
 400                 }
 401
 402                 if (size == _not(size_t))
 403                     size = framework.GetSize();
 404
 405                 switch (framework->cputype) {
 406                     case 12: switch (framework->cpusubtype) {
 407                         case 0: arch = "arm"; break;
 408                         case 6: arch = "armv6"; break;
 409                         default: arch = NULL; break;
 410                     } break;
 411
 412                     default: arch = NULL; break;
 413                 }
 414             }
 415
 416             _assert(arch != NULL);
 417
 418             pid_t pid = fork();
 419             _syscall(pid);
 420             if (pid == 0) {
 421                 char *ssize;
 422                 asprintf(&ssize, "%u", (sizeof(struct SuperBlob) + 2 * sizeof(struct BlobIndex) + sizeof(struct CodeDirectory) + strlen(base) + 1 + ((xmld == NULL ? CSSLOT_REQUIREMENTS : CSSLOT_ENTITLEMENTS) + (size + 0x1000 - 1) / 0x1000) * 0x14 + 0xc + (xmld == NULL ? 0 : 0x10 + xmls) + 15) / 16 * 16);
 423                 //printf("%s -i %s -a %s %s -o %s\n", allocate, path, arch, ssize, temp);
 424                 execlp(allocate, allocate, "-i", path, "-a", arch, ssize, "-o", temp, NULL);
 425                 _assert(false);
 426             }
 427
 428             int status;
 429             _syscall(waitpid(pid, &status, 0));
 430             _assert(WIFEXITED(status));
 431             _assert(WEXITSTATUS(status) == 0);
 432         }
 433
 434         Framework framework(temp == NULL ? path : temp);
 435         struct linkedit_data_command *signature(NULL);
 436
 437         if (flag_p)
 438             printf("path%zu='%s'\n", filei, file->c_str());
 439
 440         _foreach (load_command, framework.GetLoadCommands()) {
 441             uint32_t cmd(framework.Swap((*load_command)->cmd));
 442
 443             if (flag_R && cmd == LC_REEXPORT_DYLIB)
 444                 (*load_command)->cmd = framework.Swap(LC_LOAD_DYLIB);
 445             else if (cmd == LC_CODE_SIGNATURE)
 446                 signature = reinterpret_cast<struct linkedit_data_command *>(*load_command);
 447             else if (cmd == LC_UUID) {
 448                 volatile struct uuid_command *uuid_command(reinterpret_cast<struct uuid_command *>(*load_command));
 449
 450                 if (flag_u) {
 451                     printf("uuid%zu=%.2x%.2x%.2x%.2x-%.2x%.2x-%.2x%.2x-%.2x%.2x-%.2x%.2x%.2x%.2x%.2x%.2x\n", filei,
 452                         uuid_command->uuid[ 0], uuid_command->uuid[ 1], uuid_command->uuid[ 2], uuid_command->uuid[ 3],
 453                         uuid_command->uuid[ 4], uuid_command->uuid[ 5], uuid_command->uuid[ 6], uuid_command->uuid[ 7],
 454                         uuid_command->uuid[ 8], uuid_command->uuid[ 9], uuid_command->uuid[10], uuid_command->uuid[11],
 455                         uuid_command->uuid[12], uuid_command->uuid[13], uuid_command->uuid[14], uuid_command->uuid[15]
 456                     );
 457                 }
 458             } else if (cmd == LC_ID_DYLIB) {
 459                 volatile struct dylib_command *dylib_command(reinterpret_cast<struct dylib_command *>(*load_command));
 460
 461                 if (flag_t)
 462                     printf("time%zu=0x%.8x\n", filei, framework.Swap(dylib_command->dylib.timestamp));
 463
 464                 if (flag_T) {
 465                     uint32_t timed;
 466
 467                     if (!timeh)
 468                         timed = timev;
 469                     else {
 470                         dylib_command->dylib.timestamp = 0;
 471                         timed = hash(reinterpret_cast<uint8_t *>(framework.GetBase()), framework.GetSize(), timev);
 472                     }
 473
 474                     dylib_command->dylib.timestamp = framework.Swap(timed);
 475                 }
 476             }
 477         }
 478
 479         if (flag_s) {
 480             _assert(signature != NULL);
 481
 482             uint32_t data = framework.Swap(signature->dataoff);
 483             uint32_t size = framework.Swap(signature->datasize);
 484
 485             uint8_t *top = reinterpret_cast<uint8_t *>(framework.GetBase());
 486             uint8_t *blob = top + data;
 487             struct SuperBlob *super = reinterpret_cast<struct SuperBlob *>(blob);
 488
 489             for (size_t index(0); index != Swap(super->count); ++index)
 490                 if (Swap(super->index[index].type) == CSSLOT_CODEDIRECTORY) {
 491                     uint32_t begin = Swap(super->index[index].offset);
 492                     struct CodeDirectory *directory = reinterpret_cast<struct CodeDirectory *>(blob + begin);
 493
 494                     uint8_t (*hashes)[20] = reinterpret_cast<uint8_t (*)[20]>(blob + begin + Swap(directory->hashOffset));
 495                     uint32_t pages = Swap(directory->nCodeSlots);
 496
 497                     if (pages != 1)
 498                         for (size_t i = 0; i != pages - 1; ++i)
 499                             sha1(hashes[i], top + 0x1000 * i, 0x1000);
 500                     if (pages != 0)
 501                         sha1(hashes[pages - 1], top + 0x1000 * (pages - 1), data % 0x1000);
 502                 }
 503         }
 504
 505         if (flag_S) {
 506             _assert(signature != NULL);
 507
 508             uint32_t data = framework.Swap(signature->dataoff);
 509             uint32_t size = framework.Swap(signature->datasize);
 510
 511             uint8_t *top = reinterpret_cast<uint8_t *>(framework.GetBase());
 512             uint8_t *blob = top + data;
 513             struct SuperBlob *super = reinterpret_cast<struct SuperBlob *>(blob);
 514             super->blob.magic = Swap(CSMAGIC_EMBEDDED_SIGNATURE);
 515
 516             uint32_t count = xmld == NULL ? 2 : 3;
 517             uint32_t offset = sizeof(struct SuperBlob) + count * sizeof(struct BlobIndex);
 518
 519             super->index[0].type = Swap(CSSLOT_CODEDIRECTORY);
 520             super->index[0].offset = Swap(offset);
 521
 522             uint32_t begin = offset;
 523             struct CodeDirectory *directory = reinterpret_cast<struct CodeDirectory *>(blob + begin);
 524             offset += sizeof(struct CodeDirectory);
 525
 526             directory->blob.magic = Swap(CSMAGIC_CODEDIRECTORY);
 527             directory->version = Swap(0x00020001);
 528             directory->flags = Swap(0);
 529             directory->codeLimit = Swap(data);
 530             directory->hashSize = 0x14;
 531             directory->hashType = 0x01;
 532             directory->spare1 = 0x00;
 533             directory->pageSize = 0x0c;
 534             directory->spare2 = Swap(0);
 535
 536             directory->identOffset = Swap(offset - begin);
 537             strcpy(reinterpret_cast<char *>(blob + offset), base);
 538             offset += strlen(base) + 1;
 539
 540             uint32_t special = xmld == NULL ? CSSLOT_REQUIREMENTS : CSSLOT_ENTITLEMENTS;
 541             directory->nSpecialSlots = Swap(special);
 542
 543             uint8_t (*hashes)[20] = reinterpret_cast<uint8_t (*)[20]>(blob + offset);
 544             memset(hashes, 0, sizeof(*hashes) * special);
 545
 546             offset += sizeof(*hashes) * special;
 547             hashes += special;
 548
 549             uint32_t pages = (data + 0x1000 - 1) / 0x1000;
 550             directory->nCodeSlots = Swap(pages);
 551
 552             if (pages != 1)
 553                 for (size_t i = 0; i != pages - 1; ++i)
 554                     sha1(hashes[i], top + 0x1000 * i, 0x1000);
 555             if (pages != 0)
 556                 sha1(hashes[pages - 1], top + 0x1000 * (pages - 1), data % 0x1000);
 557
 558             directory->hashOffset = Swap(offset - begin);
 559             offset += sizeof(*hashes) * pages;
 560             directory->blob.length = Swap(offset - begin);
 561
 562             super->index[1].type = Swap(CSSLOT_REQUIREMENTS);
 563             super->index[1].offset = Swap(offset);
 564
 565             memcpy(blob + offset, "\xfa\xde\x0c\x01\x00\x00\x00\x0c\x00\x00\x00\x00", 0xc);
 566             offset += 0xc;
 567
 568             if (xmld != NULL) {
 569                 super->index[2].type = Swap(CSSLOT_ENTITLEMENTS);
 570                 super->index[2].offset = Swap(offset);
 571
 572                 uint32_t begin = offset;
 573                 struct Blob *entitlements = reinterpret_cast<struct Blob *>(blob + begin);
 574                 offset += sizeof(struct Blob);
 575
 576                 memcpy(blob + offset, xmld, xmls);
 577                 offset += xmls;
 578
 579                 entitlements->magic = Swap(CSMAGIC_ENTITLEMENTS);
 580                 entitlements->length = Swap(offset - begin);
 581             }
 582
 583             for (size_t index(0); index != count; ++index) {
 584                 uint32_t type = Swap(super->index[index].type);
 585                 if (type != 0 && type <= special) {
 586                     uint32_t offset = Swap(super->index[index].offset);
 587                     struct Blob *local = (struct Blob *) (blob + offset);
 588                     sha1((uint8_t *) (hashes - type), (uint8_t *) local, Swap(local->length));
 589                 }
 590             }
 591
 592             super->count = Swap(count);
 593             super->blob.length = Swap(offset);
 594
 595             if (offset > size) {
 596                 fprintf(stderr, "offset (%zu) > size (%zu)\n", offset, size);
 597                 _assert(false);
 598             } //else fprintf(stderr, "offset (%zu) <= size (%zu)\n", offset, size);
 599
 600             memset(blob + offset, 0, size - offset);
 601         }
 602
 603         if (temp) {
 604             struct stat info;
 605             _syscall(stat(path, &info));
 606             _syscall(chown(temp, info.st_uid, info.st_gid));
 607             _syscall(chmod(temp, info.st_mode));
 608             _syscall(unlink(path));
 609             _syscall(rename(temp, path));
 610             free(temp);
 611         }
 612
 613         free(dir);
 614         ++filei;
 615     } catch (const char *) {
 616         ++filee;
 617         ++filei;
 618     }
 619
 620     return filee;
 621 }