| 1 | #include <stdio.h> |
| 2 | #include <stdlib.h> |
| 3 | #include <string.h> |
| 4 | #include <linux/coff.h> |
| 5 | #include <assert.h> |
| 6 | #include <stdint.h> |
| 7 | |
| 8 | #include "my_assert.h" |
| 9 | |
| 10 | /* http://www.delorie.com/djgpp/doc/coff/ */ |
| 11 | |
| 12 | typedef struct { |
| 13 | unsigned short f_magic; /* magic number */ |
| 14 | unsigned short f_nscns; /* number of sections */ |
| 15 | unsigned int f_timdat; /* time & date stamp */ |
| 16 | unsigned int f_symptr; /* file pointer to symtab */ |
| 17 | unsigned int f_nsyms; /* number of symtab entries */ |
| 18 | unsigned short f_opthdr; /* sizeof(optional hdr) */ |
| 19 | unsigned short f_flags; /* flags */ |
| 20 | } FILHDR; |
| 21 | |
| 22 | typedef struct { |
| 23 | unsigned short magic; /* type of file */ |
| 24 | unsigned short vstamp; /* version stamp */ |
| 25 | unsigned int tsize; /* text size in bytes, padded to FW bdry*/ |
| 26 | unsigned int dsize; /* initialized data " " */ |
| 27 | unsigned int bsize; /* uninitialized data " " */ |
| 28 | unsigned int entry; /* entry pt. */ |
| 29 | unsigned int text_start; /* base of text used for this file */ |
| 30 | unsigned int data_start; /* base of data used for this file */ |
| 31 | } AOUTHDR; |
| 32 | |
| 33 | typedef struct { |
| 34 | char s_name[8]; /* section name */ |
| 35 | unsigned int s_paddr; /* physical address, aliased s_nlib */ |
| 36 | unsigned int s_vaddr; /* virtual address */ |
| 37 | unsigned int s_size; /* section size */ |
| 38 | unsigned int s_scnptr; /* file ptr to raw data for section */ |
| 39 | unsigned int s_relptr; /* file ptr to relocation */ |
| 40 | unsigned int s_lnnoptr; /* file ptr to line numbers */ |
| 41 | unsigned short s_nreloc; /* number of relocation entries */ |
| 42 | unsigned short s_nlnno; /* number of line number entries */ |
| 43 | unsigned int s_flags; /* flags */ |
| 44 | } SCNHDR; |
| 45 | |
| 46 | typedef struct { |
| 47 | unsigned int r_vaddr; /* address of relocation */ |
| 48 | unsigned int r_symndx; /* symbol we're adjusting for */ |
| 49 | unsigned short r_type; /* type of relocation */ |
| 50 | } __attribute__((packed)) RELOC; |
| 51 | |
| 52 | typedef struct { |
| 53 | union { |
| 54 | char e_name[E_SYMNMLEN]; |
| 55 | struct { |
| 56 | unsigned int e_zeroes; |
| 57 | unsigned int e_offset; |
| 58 | } e; |
| 59 | } e; |
| 60 | unsigned int e_value; |
| 61 | short e_scnum; |
| 62 | unsigned short e_type; |
| 63 | unsigned char e_sclass; |
| 64 | unsigned char e_numaux; |
| 65 | } __attribute__((packed)) SYMENT; |
| 66 | |
| 67 | #define C_EXT 2 |
| 68 | |
| 69 | struct my_symtab { |
| 70 | unsigned int addr; |
| 71 | //unsigned int fpos; // for patching |
| 72 | unsigned int is_text:1; |
| 73 | char *name; |
| 74 | }; |
| 75 | |
| 76 | struct my_sect_info { |
| 77 | long scnhdr_fofs; |
| 78 | long sect_fofs; |
| 79 | long reloc_fofs; |
| 80 | uint8_t *data; |
| 81 | long size; |
| 82 | RELOC *relocs; |
| 83 | long reloc_cnt; |
| 84 | }; |
| 85 | |
| 86 | static int symt_cmp(const void *p1_, const void *p2_) |
| 87 | { |
| 88 | const struct my_symtab *p1 = p1_, *p2 = p2_; |
| 89 | return p1->addr - p2->addr; |
| 90 | } |
| 91 | |
| 92 | void parse_headers(FILE *f, unsigned int *base_out, |
| 93 | struct my_sect_info *sect_i, |
| 94 | struct my_symtab **symtab_out, long *sym_cnt, |
| 95 | struct my_symtab **raw_symtab_out, long *raw_sym_cnt) |
| 96 | { |
| 97 | struct my_symtab *symt_txt = NULL; |
| 98 | struct my_symtab *symt_all = NULL; |
| 99 | char *stringtab = NULL; |
| 100 | unsigned int base = 0; |
| 101 | int text_scnum = 0; |
| 102 | long filesize; |
| 103 | char symname[9]; |
| 104 | long opthdr_pos; |
| 105 | long reloc_size; |
| 106 | FILHDR hdr; |
| 107 | AOUTHDR opthdr; |
| 108 | SCNHDR scnhdr; |
| 109 | SYMENT syment; |
| 110 | int i, s, val; |
| 111 | int ret; |
| 112 | |
| 113 | ret = fseek(f, 0, SEEK_END); |
| 114 | my_assert(ret, 0); |
| 115 | |
| 116 | filesize = ftell(f); |
| 117 | |
| 118 | ret = fseek(f, 0, SEEK_SET); |
| 119 | my_assert(ret, 0); |
| 120 | |
| 121 | ret = fread(&hdr, 1, sizeof(hdr), f); |
| 122 | my_assert(ret, sizeof(hdr)); |
| 123 | |
| 124 | if (hdr.f_magic == 0x5a4d) // MZ |
| 125 | { |
| 126 | ret = fseek(f, 0x3c, SEEK_SET); |
| 127 | my_assert(ret, 0); |
| 128 | ret = fread(&val, 1, sizeof(val), f); |
| 129 | my_assert(ret, sizeof(val)); |
| 130 | |
| 131 | ret = fseek(f, val, SEEK_SET); |
| 132 | my_assert(ret, 0); |
| 133 | ret = fread(&val, 1, sizeof(val), f); |
| 134 | my_assert(ret, sizeof(val)); |
| 135 | my_assert(val, 0x4550); // PE |
| 136 | |
| 137 | // should be COFF now |
| 138 | ret = fread(&hdr, 1, sizeof(hdr), f); |
| 139 | my_assert(ret, sizeof(hdr)); |
| 140 | } |
| 141 | |
| 142 | my_assert(hdr.f_magic, COFF_I386MAGIC); |
| 143 | |
| 144 | if (hdr.f_opthdr != 0) |
| 145 | { |
| 146 | opthdr_pos = ftell(f); |
| 147 | |
| 148 | if (hdr.f_opthdr < sizeof(opthdr)) |
| 149 | my_assert(1, 0); |
| 150 | |
| 151 | ret = fread(&opthdr, 1, sizeof(opthdr), f); |
| 152 | my_assert(ret, sizeof(opthdr)); |
| 153 | my_assert(opthdr.magic, COFF_ZMAGIC); |
| 154 | |
| 155 | //printf("text_start: %x\n", opthdr.text_start); |
| 156 | |
| 157 | if (hdr.f_opthdr > sizeof(opthdr)) { |
| 158 | ret = fread(&base, 1, sizeof(base), f); |
| 159 | my_assert(ret, sizeof(base)); |
| 160 | //printf("base: %x\n", base); |
| 161 | } |
| 162 | ret = fseek(f, opthdr_pos + hdr.f_opthdr, SEEK_SET); |
| 163 | my_assert(ret, 0); |
| 164 | } |
| 165 | |
| 166 | // note: assuming first non-empty one is .text .. |
| 167 | for (s = 0; s < hdr.f_nscns; s++) { |
| 168 | sect_i->scnhdr_fofs = ftell(f); |
| 169 | |
| 170 | ret = fread(&scnhdr, 1, sizeof(scnhdr), f); |
| 171 | my_assert(ret, sizeof(scnhdr)); |
| 172 | |
| 173 | if (scnhdr.s_size != 0) { |
| 174 | text_scnum = s + 1; |
| 175 | break; |
| 176 | } |
| 177 | } |
| 178 | my_assert(s < hdr.f_nscns, 1); |
| 179 | |
| 180 | #if 0 |
| 181 | printf("f_nsyms: %x\n", hdr.f_nsyms); |
| 182 | printf("s_name: '%s'\n", scnhdr.s_name); |
| 183 | printf("s_vaddr: %x\n", scnhdr.s_vaddr); |
| 184 | printf("s_size: %x\n", scnhdr.s_size); |
| 185 | //printf("s_scnptr: %x\n", scnhdr.s_scnptr); |
| 186 | printf("s_nreloc: %x\n", scnhdr.s_nreloc); |
| 187 | printf("--\n"); |
| 188 | #endif |
| 189 | |
| 190 | ret = fseek(f, scnhdr.s_scnptr, SEEK_SET); |
| 191 | my_assert(ret, 0); |
| 192 | |
| 193 | sect_i->data = malloc(scnhdr.s_size); |
| 194 | my_assert_not(sect_i->data, NULL); |
| 195 | ret = fread(sect_i->data, 1, scnhdr.s_size, f); |
| 196 | my_assert(ret, scnhdr.s_size); |
| 197 | |
| 198 | sect_i->sect_fofs = scnhdr.s_scnptr; |
| 199 | sect_i->size = scnhdr.s_size; |
| 200 | |
| 201 | // relocs |
| 202 | ret = fseek(f, scnhdr.s_relptr, SEEK_SET); |
| 203 | my_assert(ret, 0); |
| 204 | |
| 205 | reloc_size = scnhdr.s_nreloc * sizeof(sect_i->relocs[0]); |
| 206 | sect_i->relocs = malloc(reloc_size + 1); |
| 207 | my_assert_not(sect_i->relocs, NULL); |
| 208 | ret = fread(sect_i->relocs, 1, reloc_size, f); |
| 209 | my_assert(ret, reloc_size); |
| 210 | |
| 211 | sect_i->reloc_cnt = scnhdr.s_nreloc; |
| 212 | sect_i->reloc_fofs = scnhdr.s_relptr; |
| 213 | |
| 214 | if (base != 0 && base_out != NULL) |
| 215 | *base_out = base + scnhdr.s_vaddr; |
| 216 | |
| 217 | if (symtab_out == NULL || sym_cnt == NULL) |
| 218 | return; |
| 219 | |
| 220 | // symtab |
| 221 | if (hdr.f_nsyms != 0) { |
| 222 | symname[8] = 0; |
| 223 | |
| 224 | symt_txt = malloc(hdr.f_nsyms * sizeof(symt_txt[0]) + 1); |
| 225 | my_assert_not(symt_txt, NULL); |
| 226 | symt_all = malloc(hdr.f_nsyms * sizeof(symt_all[0]) + 1); |
| 227 | my_assert_not(symt_all, NULL); |
| 228 | |
| 229 | ret = fseek(f, hdr.f_symptr |
| 230 | + hdr.f_nsyms * sizeof(syment), SEEK_SET); |
| 231 | my_assert(ret, 0); |
| 232 | ret = fread(&i, 1, sizeof(i), f); |
| 233 | my_assert(ret, sizeof(i)); |
| 234 | my_assert((unsigned int)i < filesize, 1); |
| 235 | |
| 236 | stringtab = malloc(i); |
| 237 | my_assert_not(stringtab, NULL); |
| 238 | memset(stringtab, 0, 4); |
| 239 | ret = fread(stringtab + 4, 1, i - 4, f); |
| 240 | my_assert(ret, i - 4); |
| 241 | |
| 242 | ret = fseek(f, hdr.f_symptr, SEEK_SET); |
| 243 | my_assert(ret, 0); |
| 244 | } |
| 245 | |
| 246 | for (i = s = 0; i < hdr.f_nsyms; i++) { |
| 247 | //long pos = ftell(f); |
| 248 | |
| 249 | ret = fread(&syment, 1, sizeof(syment), f); |
| 250 | my_assert(ret, sizeof(syment)); |
| 251 | |
| 252 | strncpy(symname, syment.e.e_name, 8); |
| 253 | //printf("%3d %2d %08x '%s'\n", syment.e_sclass, |
| 254 | // syment.e_scnum, syment.e_value, symname); |
| 255 | |
| 256 | symt_all[i].addr = syment.e_value; |
| 257 | //symt_all[i].fpos = pos; |
| 258 | if (syment.e.e.e_zeroes == 0) |
| 259 | symt_all[i].name = stringtab + syment.e.e.e_offset; |
| 260 | else |
| 261 | symt_all[i].name = strdup(symname); |
| 262 | |
| 263 | symt_all[i].is_text = (syment.e_scnum == text_scnum); |
| 264 | if (symt_all[i].is_text && syment.e_sclass == C_EXT) { |
| 265 | symt_txt[s] = symt_all[i]; |
| 266 | s++; |
| 267 | } |
| 268 | |
| 269 | if (syment.e_numaux) { |
| 270 | ret = fseek(f, syment.e_numaux * sizeof(syment), |
| 271 | SEEK_CUR); |
| 272 | my_assert(ret, 0); |
| 273 | i += syment.e_numaux; |
| 274 | } |
| 275 | } |
| 276 | |
| 277 | if (symt_txt != NULL) |
| 278 | qsort(symt_txt, s, sizeof(symt_txt[0]), symt_cmp); |
| 279 | |
| 280 | *sym_cnt = s; |
| 281 | *symtab_out = symt_txt; |
| 282 | *raw_sym_cnt = i; |
| 283 | *raw_symtab_out = symt_all; |
| 284 | } |
| 285 | |
| 286 | static int handle_pad(uint8_t *d_obj, uint8_t *d_exe, int maxlen) |
| 287 | { |
| 288 | static const uint8_t p7[7] = { 0x8d, 0xa4, 0x24, 0x00, 0x00, 0x00, 0x00 }; |
| 289 | static const uint8_t p6[6] = { 0x8d, 0x9b, 0x00, 0x00, 0x00, 0x00 }; |
| 290 | static const uint8_t p5[5] = { 0x05, 0x00, 0x00, 0x00, 0x00 }; // add eax, 0 |
| 291 | static const uint8_t p4[4] = { 0x8d, 0x64, 0x24, 0x00 }; // lea |
| 292 | static const uint8_t p3[3] = { 0x8d, 0x49, 0x00 }; // lea ecx, [ecx] |
| 293 | static const uint8_t p2[2] = { 0x8b, 0xff }; // mov edi, edi |
| 294 | static const uint8_t p1[1] = { 0x90 }; // nop |
| 295 | int len; |
| 296 | int i; |
| 297 | |
| 298 | for (i = 0; i < maxlen; i++) |
| 299 | if (d_exe[i] != 0xcc) |
| 300 | break; |
| 301 | |
| 302 | for (len = i; len > 0; ) |
| 303 | { |
| 304 | i = len; |
| 305 | if (i > 7) |
| 306 | i = 7; |
| 307 | |
| 308 | switch (i) { |
| 309 | #define CASE(x) \ |
| 310 | case sizeof(p ## x): \ |
| 311 | if (memcmp(d_obj, p ## x, sizeof(p ## x))) \ |
| 312 | return 0; \ |
| 313 | memset(d_obj, 0xcc, sizeof(p ## x)); \ |
| 314 | break; |
| 315 | CASE(7) |
| 316 | CASE(6) |
| 317 | CASE(5) |
| 318 | CASE(4) |
| 319 | CASE(3) |
| 320 | CASE(2) |
| 321 | CASE(1) |
| 322 | default: |
| 323 | printf("%s: unhandled len: %d\n", __func__, len); |
| 324 | return 0; |
| 325 | #undef CASE |
| 326 | } |
| 327 | |
| 328 | len -= i; |
| 329 | d_obj += i; |
| 330 | } |
| 331 | |
| 332 | return 1; |
| 333 | } |
| 334 | |
| 335 | struct equiv_opcode { |
| 336 | signed char len; |
| 337 | signed char ofs; |
| 338 | short cmp_rm; |
| 339 | uint8_t v_masm[8]; |
| 340 | uint8_t v_masm_mask[8]; |
| 341 | uint8_t v_msvc[8]; |
| 342 | uint8_t v_msvc_mask[8]; |
| 343 | } equiv_ops[] = { |
| 344 | // cmp $0x11,%ax |
| 345 | { 4, -1, 0, |
| 346 | { 0x66,0x83,0xf8,0x03 }, { 0xff,0xff,0xff,0x00 }, |
| 347 | { 0x66,0x3d,0x03,0x00 }, { 0xff,0xff,0x00,0xff }, }, |
| 348 | // lea -0x1(%ebx,%eax,1),%esi // op mod/rm sib offs |
| 349 | // mov, test, imm grp 1 |
| 350 | { 3, -2, 1, |
| 351 | { 0x8d,0x74,0x03 }, { 0xf0,0x07,0xc0 }, |
| 352 | { 0x8d,0x74,0x18 }, { 0xf0,0x07,0xc0 }, }, |
| 353 | // movzbl 0x58f24a(%eax,%ecx,1),%eax |
| 354 | { 4, -3, 1, |
| 355 | { 0x0f,0xb6,0x84,0x08 }, { 0xff,0xff,0x07,0xc0 }, |
| 356 | { 0x0f,0xb6,0x84,0x01 }, { 0xff,0xff,0x07,0xc0 }, }, |
| 357 | // inc/dec |
| 358 | { 3, -2, 1, |
| 359 | { 0xfe,0x4c,0x03 }, { 0xfe,0xff,0xc0 }, |
| 360 | { 0xfe,0x4c,0x18 }, { 0xfe,0xff,0xc0 }, }, |
| 361 | // cmp |
| 362 | { 3, -2, 1, |
| 363 | { 0x38,0x0c,0x0c }, { 0xff,0xff,0xc0 }, |
| 364 | { 0x38,0x0c,0x30 }, { 0xff,0xff,0xc0 }, }, |
| 365 | // test %dl,%bl |
| 366 | { 2, -1, 1, |
| 367 | { 0x84,0xd3 }, { 0xfe,0xc0 }, |
| 368 | { 0x84,0xda }, { 0xfe,0xc0 }, }, |
| 369 | // cmp r,r/m vs rm/r |
| 370 | { 2, 0, 1, |
| 371 | { 0x3a,0xca }, { 0xff,0xc0 }, |
| 372 | { 0x38,0xd1 }, { 0xff,0xc0 }, }, |
| 373 | // rep + 66 prefix |
| 374 | { 2, 0, 0, |
| 375 | { 0xf3,0x66 }, { 0xfe,0xff }, |
| 376 | { 0x66,0xf3 }, { 0xff,0xfe }, }, |
| 377 | // fadd st, st(0) vs st(0), st |
| 378 | { 2, 0, 0, |
| 379 | { 0xd8,0xc0 }, { 0xff,0xf7 }, |
| 380 | { 0xdc,0xc0 }, { 0xff,0xf7 }, }, |
| 381 | |
| 382 | // broad filters (may take too much..) |
| 383 | // testb $0x4,0x1d(%esi,%eax,1) |
| 384 | // movb, push, .. |
| 385 | { 3, -2, 1, |
| 386 | { 0xf6,0x44,0x06 }, { 0x00,0x07,0xc0 }, |
| 387 | { 0xf6,0x44,0x30 }, { 0x00,0x07,0xc0 }, }, |
| 388 | }; |
| 389 | |
| 390 | static int cmp_mask(uint8_t *d, uint8_t *expect, uint8_t *mask, int len) |
| 391 | { |
| 392 | int i; |
| 393 | |
| 394 | for (i = 0; i < len; i++) |
| 395 | if ((d[i] & mask[i]) != (expect[i] & mask[i])) |
| 396 | return 1; |
| 397 | |
| 398 | return 0; |
| 399 | } |
| 400 | |
| 401 | static int check_equiv(uint8_t *d_obj, uint8_t *d_exe, int maxlen) |
| 402 | { |
| 403 | uint8_t vo, ve, vo2, ve2; |
| 404 | int i, jo, je; |
| 405 | int len, ofs; |
| 406 | |
| 407 | for (i = 0; i < sizeof(equiv_ops) / sizeof(equiv_ops[0]); i++) |
| 408 | { |
| 409 | struct equiv_opcode *op = &equiv_ops[i]; |
| 410 | |
| 411 | len = op->len; |
| 412 | if (maxlen < len) |
| 413 | continue; |
| 414 | |
| 415 | ofs = op->ofs; |
| 416 | if (cmp_mask(d_obj + ofs, op->v_masm, |
| 417 | op->v_masm_mask, len)) |
| 418 | continue; |
| 419 | if (cmp_mask(d_exe + ofs, op->v_msvc, |
| 420 | op->v_msvc_mask, len)) |
| 421 | continue; |
| 422 | |
| 423 | jo = je = 0; |
| 424 | d_obj += ofs; |
| 425 | d_exe += ofs; |
| 426 | while (1) |
| 427 | { |
| 428 | for (; jo < len; jo++) |
| 429 | if (op->v_masm_mask[jo] != 0xff) |
| 430 | break; |
| 431 | for (; je < len; je++) |
| 432 | if (op->v_msvc_mask[je] != 0xff) |
| 433 | break; |
| 434 | |
| 435 | if ((jo == len && je != len) || (jo != len && je == len)) { |
| 436 | printf("invalid equiv_ops\n"); |
| 437 | return -1; |
| 438 | } |
| 439 | if (jo == len) |
| 440 | return len + ofs - 1; // matched |
| 441 | |
| 442 | // var byte |
| 443 | vo = d_obj[jo] & ~op->v_masm_mask[jo]; |
| 444 | ve = d_exe[je] & ~op->v_msvc_mask[je]; |
| 445 | if (op->cmp_rm && op->v_masm_mask[jo] == 0xc0) { |
| 446 | vo2 = vo >> 3; |
| 447 | vo &= 7; |
| 448 | ve2 = ve & 7; |
| 449 | ve >>= 3; |
| 450 | if (vo != ve || vo2 != ve2) |
| 451 | return -1; |
| 452 | } |
| 453 | else { |
| 454 | if (vo != ve) |
| 455 | return -1; |
| 456 | } |
| 457 | |
| 458 | jo++; |
| 459 | je++; |
| 460 | } |
| 461 | } |
| 462 | |
| 463 | return -1; |
| 464 | } |
| 465 | |
| 466 | static void fill_int3(unsigned char *d, int len) |
| 467 | { |
| 468 | while (len-- > 0) { |
| 469 | if (d[0] == 0xcc && d[1] == 0xcc) |
| 470 | break; |
| 471 | *d++ = 0xcc; |
| 472 | } |
| 473 | } |
| 474 | |
| 475 | int main(int argc, char *argv[]) |
| 476 | { |
| 477 | unsigned int base = 0, addr, end, sym, *t; |
| 478 | struct my_sect_info s_text_obj, s_text_exe; |
| 479 | struct my_symtab *raw_syms_obj = NULL; |
| 480 | struct my_symtab *syms_obj = NULL; |
| 481 | long sym_cnt_obj, raw_sym_cnt_obj; |
| 482 | FILE *f_obj, *f_exe; |
| 483 | SCNHDR tmphdr; |
| 484 | long sztext_cmn; |
| 485 | int do_cmp = 1; |
| 486 | int retval = 1; |
| 487 | int left; |
| 488 | int arg; |
| 489 | int ret; |
| 490 | int i; |
| 491 | |
| 492 | for (arg = 1; arg < argc; arg++) { |
| 493 | if (!strcmp(argv[arg], "-n")) |
| 494 | do_cmp = 0; |
| 495 | else |
| 496 | break; |
| 497 | } |
| 498 | |
| 499 | if (argc != arg + 2) { |
| 500 | printf("usage:\n%s [-n] <a_obj> <exe>\n", argv[0]); |
| 501 | return 1; |
| 502 | } |
| 503 | |
| 504 | f_obj = fopen(argv[arg++], "r+b"); |
| 505 | if (f_obj == NULL) { |
| 506 | fprintf(stderr, "%s: ", argv[1]); |
| 507 | perror(""); |
| 508 | return 1; |
| 509 | } |
| 510 | |
| 511 | f_exe = fopen(argv[arg++], "r"); |
| 512 | if (f_exe == NULL) { |
| 513 | fprintf(stderr, "%s: ", argv[2]); |
| 514 | perror(""); |
| 515 | return 1; |
| 516 | } |
| 517 | |
| 518 | parse_headers(f_obj, NULL, &s_text_obj, &syms_obj, &sym_cnt_obj, |
| 519 | &raw_syms_obj, &raw_sym_cnt_obj); |
| 520 | parse_headers(f_exe, &base, &s_text_exe, NULL, NULL, NULL, NULL); |
| 521 | |
| 522 | sztext_cmn = s_text_obj.size; |
| 523 | if (sztext_cmn > s_text_exe.size) |
| 524 | sztext_cmn = s_text_exe.size; |
| 525 | |
| 526 | if (sztext_cmn == 0) { |
| 527 | printf("bad .text size(s): %ld, %ld\n", |
| 528 | s_text_obj.size, s_text_exe.size); |
| 529 | return 1; |
| 530 | } |
| 531 | |
| 532 | for (i = 0; i < s_text_obj.reloc_cnt; i++) |
| 533 | { |
| 534 | unsigned int a = s_text_obj.relocs[i].r_vaddr; |
| 535 | //printf("%04x %08x\n", s_text_obj.relocs[i].r_type, a); |
| 536 | |
| 537 | switch (s_text_obj.relocs[i].r_type) { |
| 538 | case 0x06: // RELOC_ADDR32 |
| 539 | case 0x14: // RELOC_REL32 |
| 540 | // must preserve stored val, |
| 541 | // so trash exe so that cmp passes |
| 542 | memcpy(s_text_exe.data + a, s_text_obj.data + a, 4); |
| 543 | break; |
| 544 | default: |
| 545 | printf("unknown reloc %x @%08x/%08x\n", |
| 546 | s_text_obj.relocs[i].r_type, a, base + a); |
| 547 | return 1; |
| 548 | } |
| 549 | } |
| 550 | |
| 551 | if (do_cmp) |
| 552 | for (i = 0; i < sztext_cmn; i++) |
| 553 | { |
| 554 | if (s_text_obj.data[i] == s_text_exe.data[i]) |
| 555 | continue; |
| 556 | |
| 557 | left = sztext_cmn - i; |
| 558 | |
| 559 | if (s_text_exe.data[i] == 0xcc) { // padding |
| 560 | if (handle_pad(s_text_obj.data + i, |
| 561 | s_text_exe.data + i, left)) |
| 562 | continue; |
| 563 | } |
| 564 | |
| 565 | ret = check_equiv(s_text_obj.data + i, s_text_exe.data + i, left); |
| 566 | if (ret >= 0) { |
| 567 | i += ret; |
| 568 | continue; |
| 569 | } |
| 570 | |
| 571 | printf("%x: %02x vs %02x\n", base + i, |
| 572 | s_text_obj.data[i], s_text_exe.data[i]); |
| 573 | goto out; |
| 574 | } |
| 575 | |
| 576 | // fill removed funcs with 'int3' |
| 577 | for (i = 0; i < sym_cnt_obj; i++) { |
| 578 | if (strncmp(syms_obj[i].name, "rm_", 3)) |
| 579 | continue; |
| 580 | |
| 581 | addr = syms_obj[i].addr; |
| 582 | end = (i < sym_cnt_obj - 1) |
| 583 | ? syms_obj[i + 1].addr : s_text_obj.size; |
| 584 | if (addr >= s_text_obj.size || end > s_text_obj.size) { |
| 585 | printf("addr OOR: %x-%x '%s'\n", addr, end, |
| 586 | syms_obj[i].name); |
| 587 | goto out; |
| 588 | } |
| 589 | fill_int3(s_text_obj.data + addr, end - addr); |
| 590 | } |
| 591 | |
| 592 | // remove relocs |
| 593 | for (i = 0; i < s_text_obj.reloc_cnt; i++) { |
| 594 | addr = s_text_obj.relocs[i].r_vaddr; |
| 595 | sym = s_text_obj.relocs[i].r_symndx; |
| 596 | if (addr > s_text_obj.size - 4) { |
| 597 | printf("reloc addr OOR: %x\n", addr); |
| 598 | goto out; |
| 599 | } |
| 600 | if (sym >= raw_sym_cnt_obj) { |
| 601 | printf("reloc sym OOR: %d/%ld\n", |
| 602 | sym, raw_sym_cnt_obj); |
| 603 | goto out; |
| 604 | } |
| 605 | #if 0 |
| 606 | printf("r %08x -> %08x %s\n", base + addr, |
| 607 | raw_syms_obj[sym].addr, |
| 608 | raw_syms_obj[sym].name); |
| 609 | #endif |
| 610 | t = (unsigned int *)(s_text_obj.data + addr); |
| 611 | if (t[0] == 0xcccccccc |
| 612 | || t[-1] == 0xcccccccc) { // jumptab of a func? |
| 613 | t[0] = 0xcccccccc; |
| 614 | memmove(&s_text_obj.relocs[i], |
| 615 | &s_text_obj.relocs[i + 1], |
| 616 | (s_text_obj.reloc_cnt - i - 1) |
| 617 | * sizeof(s_text_obj.relocs[0])); |
| 618 | i--; |
| 619 | s_text_obj.reloc_cnt--; |
| 620 | } |
| 621 | #if 0 |
| 622 | // note: branches/calls already linked, |
| 623 | // so only useful for dd refs |
| 624 | // XXX: rm'd because of switch tables |
| 625 | else if (raw_syms_obj[sym].is_text) { |
| 626 | unsigned int addr2 = raw_syms_obj[sym].addr; |
| 627 | if (s_text_obj.data[addr2] == 0xcc) { |
| 628 | printf("warning: reloc %08x -> %08x " |
| 629 | "points to rm'd target '%s'\n", |
| 630 | base + addr, base + addr2, |
| 631 | raw_syms_obj[sym].name); |
| 632 | } |
| 633 | } |
| 634 | #endif |
| 635 | } |
| 636 | |
| 637 | // patch .text |
| 638 | ret = fseek(f_obj, s_text_obj.sect_fofs, SEEK_SET); |
| 639 | my_assert(ret, 0); |
| 640 | ret = fwrite(s_text_obj.data, 1, s_text_obj.size, f_obj); |
| 641 | my_assert(ret, s_text_obj.size); |
| 642 | |
| 643 | // patch relocs |
| 644 | ret = fseek(f_obj, s_text_obj.reloc_fofs, SEEK_SET); |
| 645 | my_assert(ret, 0); |
| 646 | ret = fwrite(s_text_obj.relocs, sizeof(s_text_obj.relocs[0]), |
| 647 | s_text_obj.reloc_cnt, f_obj); |
| 648 | my_assert(ret, s_text_obj.reloc_cnt); |
| 649 | |
| 650 | ret = fseek(f_obj, s_text_obj.scnhdr_fofs, SEEK_SET); |
| 651 | my_assert(ret, 0); |
| 652 | ret = fread(&tmphdr, 1, sizeof(tmphdr), f_obj); |
| 653 | my_assert(ret, sizeof(tmphdr)); |
| 654 | |
| 655 | tmphdr.s_nreloc = s_text_obj.reloc_cnt; |
| 656 | |
| 657 | ret = fseek(f_obj, s_text_obj.scnhdr_fofs, SEEK_SET); |
| 658 | my_assert(ret, 0); |
| 659 | ret = fwrite(&tmphdr, 1, sizeof(tmphdr), f_obj); |
| 660 | my_assert(ret, sizeof(tmphdr)); |
| 661 | |
| 662 | fclose(f_obj); |
| 663 | fclose(f_exe); |
| 664 | |
| 665 | retval = 0; |
| 666 | out: |
| 667 | return retval; |
| 668 | } |