| 1 | /* ELF program property support. |
| 2 | Copyright (C) 2017 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of BFD, the Binary File Descriptor library. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 3 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program; if not, write to the Free Software |
| 18 | Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, |
| 19 | MA 02110-1301, USA. */ |
| 20 | |
| 21 | /* GNU program property draft is at: |
| 22 | |
| 23 | https://github.com/hjl-tools/linux-abi/wiki/property-draft.pdf |
| 24 | */ |
| 25 | |
| 26 | #include "sysdep.h" |
| 27 | #include "bfd.h" |
| 28 | #include "libbfd.h" |
| 29 | #include "elf-bfd.h" |
| 30 | |
| 31 | /* Get a property, allocate a new one if needed. */ |
| 32 | |
| 33 | elf_property * |
| 34 | _bfd_elf_get_property (bfd *abfd, unsigned int type, unsigned int datasz) |
| 35 | { |
| 36 | elf_property_list *p, **lastp; |
| 37 | |
| 38 | if (bfd_get_flavour (abfd) != bfd_target_elf_flavour) |
| 39 | { |
| 40 | /* Never should happen. */ |
| 41 | abort (); |
| 42 | } |
| 43 | |
| 44 | /* Keep the property list in order of type. */ |
| 45 | lastp = &elf_properties (abfd); |
| 46 | for (p = *lastp; p; p = p->next) |
| 47 | { |
| 48 | /* Reuse the existing entry. */ |
| 49 | if (type == p->property.pr_type) |
| 50 | { |
| 51 | if (datasz > p->property.pr_datasz) |
| 52 | { |
| 53 | /* This can happen when mixing 32-bit and 64-bit objects. */ |
| 54 | p->property.pr_datasz = datasz; |
| 55 | } |
| 56 | return &p->property; |
| 57 | } |
| 58 | else if (type < p->property.pr_type) |
| 59 | break; |
| 60 | lastp = &p->next; |
| 61 | } |
| 62 | p = (elf_property_list *) bfd_alloc (abfd, sizeof (*p)); |
| 63 | if (p == NULL) |
| 64 | { |
| 65 | _bfd_error_handler (_("%B: out of memory in _bfd_elf_get_property"), |
| 66 | abfd); |
| 67 | _exit (EXIT_FAILURE); |
| 68 | } |
| 69 | memset (p, 0, sizeof (*p)); |
| 70 | p->property.pr_type = type; |
| 71 | p->property.pr_datasz = datasz; |
| 72 | p->next = *lastp; |
| 73 | *lastp = p; |
| 74 | return &p->property; |
| 75 | } |
| 76 | |
| 77 | /* Parse GNU properties. */ |
| 78 | |
| 79 | bfd_boolean |
| 80 | _bfd_elf_parse_gnu_properties (bfd *abfd, Elf_Internal_Note *note) |
| 81 | { |
| 82 | const struct elf_backend_data *bed = get_elf_backend_data (abfd); |
| 83 | unsigned int align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4; |
| 84 | bfd_byte *ptr = (bfd_byte *) note->descdata; |
| 85 | bfd_byte *ptr_end = ptr + note->descsz; |
| 86 | |
| 87 | if (note->descsz < 8 || (note->descsz % align_size) != 0) |
| 88 | { |
| 89 | bad_size: |
| 90 | _bfd_error_handler |
| 91 | (_("warning: %B: corrupt GNU_PROPERTY_TYPE (%ld) size: %#lx\n"), |
| 92 | abfd, note->type, note->descsz); |
| 93 | return FALSE; |
| 94 | } |
| 95 | |
| 96 | while (1) |
| 97 | { |
| 98 | unsigned int type = bfd_h_get_32 (abfd, ptr); |
| 99 | unsigned int datasz = bfd_h_get_32 (abfd, ptr + 4); |
| 100 | elf_property *prop; |
| 101 | |
| 102 | ptr += 8; |
| 103 | |
| 104 | if ((ptr + datasz) > ptr_end) |
| 105 | { |
| 106 | _bfd_error_handler |
| 107 | (_("warning: %B: corrupt GNU_PROPERTY_TYPE (%ld) type (0x%x) datasz: 0x%x\n"), |
| 108 | abfd, note->type, type, datasz); |
| 109 | /* Clear all properties. */ |
| 110 | elf_properties (abfd) = NULL; |
| 111 | return FALSE; |
| 112 | } |
| 113 | |
| 114 | if (type >= GNU_PROPERTY_LOPROC) |
| 115 | { |
| 116 | if (type < GNU_PROPERTY_LOUSER && bed->parse_gnu_properties) |
| 117 | { |
| 118 | enum elf_property_kind kind |
| 119 | = bed->parse_gnu_properties (abfd, type, ptr, datasz); |
| 120 | if (kind == property_corrupt) |
| 121 | { |
| 122 | /* Clear all properties. */ |
| 123 | elf_properties (abfd) = NULL; |
| 124 | return FALSE; |
| 125 | } |
| 126 | else if (kind != property_ignored) |
| 127 | goto next; |
| 128 | } |
| 129 | } |
| 130 | else |
| 131 | { |
| 132 | switch (type) |
| 133 | { |
| 134 | case GNU_PROPERTY_STACK_SIZE: |
| 135 | if (datasz != align_size) |
| 136 | { |
| 137 | _bfd_error_handler |
| 138 | (_("warning: %B: corrupt stack size: 0x%x\n"), |
| 139 | abfd, datasz); |
| 140 | /* Clear all properties. */ |
| 141 | elf_properties (abfd) = NULL; |
| 142 | return FALSE; |
| 143 | } |
| 144 | prop = _bfd_elf_get_property (abfd, type, datasz); |
| 145 | if (datasz == 8) |
| 146 | prop->u.number = bfd_h_get_64 (abfd, ptr); |
| 147 | else |
| 148 | prop->u.number = bfd_h_get_32 (abfd, ptr); |
| 149 | prop->pr_kind = property_number; |
| 150 | goto next; |
| 151 | |
| 152 | case GNU_PROPERTY_NO_COPY_ON_PROTECTED: |
| 153 | if (datasz != 0) |
| 154 | { |
| 155 | _bfd_error_handler |
| 156 | (_("warning: %B: corrupt no copy on protected size: 0x%x\n"), |
| 157 | abfd, datasz); |
| 158 | /* Clear all properties. */ |
| 159 | elf_properties (abfd) = NULL; |
| 160 | return FALSE; |
| 161 | } |
| 162 | prop = _bfd_elf_get_property (abfd, type, datasz); |
| 163 | prop->pr_kind = property_number; |
| 164 | goto next; |
| 165 | |
| 166 | default: |
| 167 | break; |
| 168 | } |
| 169 | } |
| 170 | |
| 171 | _bfd_error_handler |
| 172 | (_("warning: %B: unsupported GNU_PROPERTY_TYPE (%ld) type: 0x%x\n"), |
| 173 | abfd, note->type, type); |
| 174 | |
| 175 | next: |
| 176 | ptr += (datasz + (align_size - 1)) & ~ (align_size - 1); |
| 177 | if (ptr == ptr_end) |
| 178 | break; |
| 179 | |
| 180 | if (ptr > (ptr_end - 8)) |
| 181 | goto bad_size; |
| 182 | } |
| 183 | |
| 184 | return TRUE; |
| 185 | } |
| 186 | |
| 187 | /* Merge GNU property BPROP with APROP. If APROP isn't NULL, return TRUE |
| 188 | if APROP is updated. Otherwise, return TRUE if BPROP should be merged |
| 189 | with ABFD. */ |
| 190 | |
| 191 | static bfd_boolean |
| 192 | elf_merge_gnu_properties (bfd *abfd, elf_property *aprop, |
| 193 | elf_property *bprop) |
| 194 | { |
| 195 | const struct elf_backend_data *bed = get_elf_backend_data (abfd); |
| 196 | unsigned int pr_type = aprop != NULL ? aprop->pr_type : bprop->pr_type; |
| 197 | |
| 198 | if (bed->merge_gnu_properties != NULL |
| 199 | && pr_type >= GNU_PROPERTY_LOPROC |
| 200 | && pr_type < GNU_PROPERTY_LOUSER) |
| 201 | return bed->merge_gnu_properties (abfd, aprop, bprop); |
| 202 | |
| 203 | switch (pr_type) |
| 204 | { |
| 205 | case GNU_PROPERTY_STACK_SIZE: |
| 206 | if (aprop != NULL && bprop != NULL) |
| 207 | { |
| 208 | if (bprop->u.number > aprop->u.number) |
| 209 | { |
| 210 | aprop->u.number = bprop->u.number; |
| 211 | return TRUE; |
| 212 | } |
| 213 | break; |
| 214 | } |
| 215 | /* FALLTHROUGH */ |
| 216 | |
| 217 | case GNU_PROPERTY_NO_COPY_ON_PROTECTED: |
| 218 | /* Return TRUE if APROP is NULL to indicate that BPROP should |
| 219 | be added to ABFD. */ |
| 220 | return aprop == NULL; |
| 221 | |
| 222 | default: |
| 223 | /* Never should happen. */ |
| 224 | abort (); |
| 225 | } |
| 226 | |
| 227 | return FALSE; |
| 228 | } |
| 229 | |
| 230 | /* Return the property of TYPE on *LISTP and remove it from *LISTP. |
| 231 | Return NULL if not found. */ |
| 232 | |
| 233 | static elf_property * |
| 234 | elf_find_and_remove_property (elf_property_list **listp, |
| 235 | unsigned int type) |
| 236 | { |
| 237 | elf_property_list *list; |
| 238 | |
| 239 | for (list = *listp; list; list = list->next) |
| 240 | { |
| 241 | if (type == list->property.pr_type) |
| 242 | { |
| 243 | /* Remove this property. */ |
| 244 | *listp = list->next; |
| 245 | return &list->property; |
| 246 | } |
| 247 | else if (type < list->property.pr_type) |
| 248 | break; |
| 249 | listp = &list->next; |
| 250 | } |
| 251 | |
| 252 | return NULL; |
| 253 | } |
| 254 | |
| 255 | /* Merge GNU property list *LISTP with ABFD. */ |
| 256 | |
| 257 | static void |
| 258 | elf_merge_gnu_property_list (bfd *abfd, elf_property_list **listp) |
| 259 | { |
| 260 | elf_property_list *p, **lastp; |
| 261 | elf_property *pr; |
| 262 | |
| 263 | /* Merge each GNU property in ABFD with the one on *LISTP. */ |
| 264 | lastp = &elf_properties (abfd); |
| 265 | for (p = *lastp; p; p = p->next) |
| 266 | { |
| 267 | pr = elf_find_and_remove_property (listp, p->property.pr_type); |
| 268 | /* Pass NULL to elf_merge_gnu_properties for the property which |
| 269 | isn't on *LISTP. */ |
| 270 | elf_merge_gnu_properties (abfd, &p->property, pr); |
| 271 | if (p->property.pr_kind == property_remove) |
| 272 | { |
| 273 | /* Remove this property. */ |
| 274 | *lastp = p->next; |
| 275 | continue; |
| 276 | } |
| 277 | lastp = &p->next; |
| 278 | } |
| 279 | |
| 280 | /* Merge the remaining properties on *LISTP with ABFD. */ |
| 281 | for (p = *listp; p != NULL; p = p->next) |
| 282 | if (elf_merge_gnu_properties (abfd, NULL, &p->property)) |
| 283 | { |
| 284 | pr = _bfd_elf_get_property (abfd, p->property.pr_type, |
| 285 | p->property.pr_datasz); |
| 286 | /* It must be a new property. */ |
| 287 | if (pr->pr_kind != property_unknown) |
| 288 | abort (); |
| 289 | /* Add a new property. */ |
| 290 | *pr = p->property; |
| 291 | } |
| 292 | } |
| 293 | |
| 294 | /* Set up GNU properties. */ |
| 295 | |
| 296 | void |
| 297 | _bfd_elf_link_setup_gnu_properties (struct bfd_link_info *info) |
| 298 | { |
| 299 | bfd *abfd, *first_pbfd = NULL; |
| 300 | elf_property_list *list; |
| 301 | asection *sec; |
| 302 | bfd_boolean has_properties = FALSE; |
| 303 | const struct elf_backend_data *bed |
| 304 | = get_elf_backend_data (info->output_bfd); |
| 305 | unsigned int elfclass = bed->s->elfclass; |
| 306 | int elf_machine_code = bed->elf_machine_code; |
| 307 | |
| 308 | /* Find the first relocatable ELF input with GNU properties. */ |
| 309 | for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next) |
| 310 | if (bfd_get_flavour (abfd) == bfd_target_elf_flavour |
| 311 | && bfd_count_sections (abfd) != 0 |
| 312 | && elf_properties (abfd) != NULL) |
| 313 | { |
| 314 | has_properties = TRUE; |
| 315 | |
| 316 | /* Ignore GNU properties from ELF objects with different machine |
| 317 | code or class. */ |
| 318 | if ((elf_machine_code |
| 319 | == get_elf_backend_data (abfd)->elf_machine_code) |
| 320 | && (elfclass |
| 321 | == get_elf_backend_data (abfd)->s->elfclass)) |
| 322 | { |
| 323 | /* Keep .note.gnu.property section in FIRST_PBFD. */ |
| 324 | first_pbfd = abfd; |
| 325 | break; |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | /* Do nothing if there is no .note.gnu.property section. */ |
| 330 | if (!has_properties) |
| 331 | return; |
| 332 | |
| 333 | /* Merge .note.gnu.property sections. */ |
| 334 | for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next) |
| 335 | if (abfd != first_pbfd && bfd_count_sections (abfd) != 0) |
| 336 | { |
| 337 | elf_property_list *null_ptr = NULL; |
| 338 | elf_property_list **listp = &null_ptr; |
| 339 | |
| 340 | /* Merge .note.gnu.property section in relocatable ELF input. */ |
| 341 | if (bfd_get_flavour (abfd) == bfd_target_elf_flavour) |
| 342 | { |
| 343 | list = elf_properties (abfd); |
| 344 | |
| 345 | /* Ignore GNU properties from ELF objects with different |
| 346 | machine code. */ |
| 347 | if (list != NULL |
| 348 | && (elf_machine_code |
| 349 | == get_elf_backend_data (abfd)->elf_machine_code)) |
| 350 | listp = &elf_properties (abfd); |
| 351 | } |
| 352 | else |
| 353 | list = NULL; |
| 354 | |
| 355 | /* Merge properties with FIRST_PBFD. FIRST_PBFD can be NULL |
| 356 | when all properties are from ELF objects with different |
| 357 | machine code or class. */ |
| 358 | if (first_pbfd != NULL) |
| 359 | elf_merge_gnu_property_list (first_pbfd, listp); |
| 360 | |
| 361 | if (list != NULL) |
| 362 | { |
| 363 | /* Discard .note.gnu.property section in the rest inputs. */ |
| 364 | sec = bfd_get_section_by_name (abfd, |
| 365 | NOTE_GNU_PROPERTY_SECTION_NAME); |
| 366 | sec->output_section = bfd_abs_section_ptr; |
| 367 | } |
| 368 | } |
| 369 | |
| 370 | /* Rewrite .note.gnu.property section so that GNU properties are |
| 371 | always sorted by type even if input GNU properties aren't sorted. */ |
| 372 | if (first_pbfd != NULL) |
| 373 | { |
| 374 | unsigned int size; |
| 375 | unsigned int descsz; |
| 376 | bfd_byte *contents; |
| 377 | Elf_External_Note *e_note; |
| 378 | unsigned int align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4; |
| 379 | |
| 380 | sec = bfd_get_section_by_name (first_pbfd, |
| 381 | NOTE_GNU_PROPERTY_SECTION_NAME); |
| 382 | |
| 383 | /* Update stack size in .note.gnu.property with -z stack-size=N |
| 384 | if N > 0. */ |
| 385 | if (info->stacksize > 0) |
| 386 | { |
| 387 | elf_property *p; |
| 388 | bfd_vma stacksize = info->stacksize; |
| 389 | |
| 390 | p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_STACK_SIZE, |
| 391 | align_size); |
| 392 | if (p->pr_kind == property_unknown) |
| 393 | { |
| 394 | /* Create GNU_PROPERTY_STACK_SIZE. */ |
| 395 | p->u.number = stacksize; |
| 396 | p->pr_kind = property_number; |
| 397 | } |
| 398 | else if (stacksize > p->u.number) |
| 399 | p->u.number = stacksize; |
| 400 | } |
| 401 | else if (elf_properties (first_pbfd) == NULL) |
| 402 | { |
| 403 | /* Discard .note.gnu.property section if all properties have |
| 404 | been removed. */ |
| 405 | sec->output_section = bfd_abs_section_ptr; |
| 406 | return; |
| 407 | } |
| 408 | |
| 409 | /* Compute the section size. */ |
| 410 | descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]); |
| 411 | descsz = (descsz + 3) & -(unsigned int) 4; |
| 412 | size = descsz; |
| 413 | for (list = elf_properties (first_pbfd); |
| 414 | list != NULL; |
| 415 | list = list->next) |
| 416 | { |
| 417 | /* There are 4 byte type + 4 byte datasz for each property. */ |
| 418 | size += 4 + 4 + list->property.pr_datasz; |
| 419 | /* Align each property. */ |
| 420 | size = (size + (align_size - 1)) & ~(align_size - 1); |
| 421 | } |
| 422 | |
| 423 | /* Update .note.gnu.property section now. */ |
| 424 | sec->size = size; |
| 425 | contents = (bfd_byte *) bfd_zalloc (first_pbfd, size); |
| 426 | |
| 427 | e_note = (Elf_External_Note *) contents; |
| 428 | bfd_h_put_32 (first_pbfd, sizeof "GNU", &e_note->namesz); |
| 429 | bfd_h_put_32 (first_pbfd, size - descsz, &e_note->descsz); |
| 430 | bfd_h_put_32 (first_pbfd, NT_GNU_PROPERTY_TYPE_0, &e_note->type); |
| 431 | memcpy (e_note->name, "GNU", sizeof "GNU"); |
| 432 | |
| 433 | size = descsz; |
| 434 | for (list = elf_properties (first_pbfd); |
| 435 | list != NULL; |
| 436 | list = list->next) |
| 437 | { |
| 438 | /* There are 4 byte type + 4 byte datasz for each property. */ |
| 439 | bfd_h_put_32 (first_pbfd, list->property.pr_type, |
| 440 | contents + size); |
| 441 | bfd_h_put_32 (first_pbfd, list->property.pr_datasz, |
| 442 | contents + size + 4); |
| 443 | size += 4 + 4; |
| 444 | |
| 445 | /* Write out property value. */ |
| 446 | switch (list->property.pr_kind) |
| 447 | { |
| 448 | case property_number: |
| 449 | switch (list->property.pr_datasz) |
| 450 | { |
| 451 | default: |
| 452 | /* Never should happen. */ |
| 453 | abort (); |
| 454 | |
| 455 | case 0: |
| 456 | break; |
| 457 | |
| 458 | case 4: |
| 459 | bfd_h_put_32 (first_pbfd, list->property.u.number, |
| 460 | contents + size); |
| 461 | break; |
| 462 | |
| 463 | case 8: |
| 464 | bfd_h_put_64 (first_pbfd, list->property.u.number, |
| 465 | contents + size); |
| 466 | break; |
| 467 | } |
| 468 | break; |
| 469 | |
| 470 | default: |
| 471 | /* Never should happen. */ |
| 472 | abort (); |
| 473 | } |
| 474 | size += list->property.pr_datasz; |
| 475 | |
| 476 | /* Align each property. */ |
| 477 | size = (size + (align_size - 1)) & ~ (align_size - 1); |
| 478 | } |
| 479 | |
| 480 | /* Cache the section contents for elf_link_input_bfd. */ |
| 481 | elf_section_data (sec)->this_hdr.contents = contents; |
| 482 | } |
| 483 | } |