bfd/elf-properties.c

   1 /* ELF program property support.
   2    Copyright (C) 2017-2025 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 (_("%pB: 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 bool
  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: %pB: corrupt GNU_PROPERTY_TYPE (%ld) size: %#lx"),
  92          abfd, note->type, note->descsz);
  93       return false;
  94     }
  95
  96   while (ptr != ptr_end)
  97     {
  98       unsigned int type;
  99       unsigned int datasz;
 100       elf_property *prop;
 101
 102       if ((size_t) (ptr_end - ptr) < 8)
 103         goto bad_size;
 104
 105       type = bfd_h_get_32 (abfd, ptr);
 106       datasz = bfd_h_get_32 (abfd, ptr + 4);
 107       ptr += 8;
 108
 109       if (datasz > (size_t) (ptr_end - ptr))
 110         {
 111           _bfd_error_handler
 112             (_("warning: %pB: corrupt GNU_PROPERTY_TYPE (%ld) type (0x%x) datasz: 0x%x"),
 113              abfd, note->type, type, datasz);
 114           /* Clear all properties.  */
 115           elf_properties (abfd) = NULL;
 116           return false;
 117         }
 118
 119       if (type >= GNU_PROPERTY_LOPROC)
 120         {
 121           if (bed->elf_machine_code == EM_NONE)
 122             {
 123               /* Ignore processor-specific properties with generic ELF
 124                  target vector.  They should be handled by the matching
 125                  ELF target vector.  */
 126               goto next;
 127             }
 128           else if (type < GNU_PROPERTY_LOUSER
 129                    && bed->parse_gnu_properties)
 130             {
 131               enum elf_property_kind kind
 132                 = bed->parse_gnu_properties (abfd, type, ptr, datasz);
 133               if (kind == property_corrupt)
 134                 {
 135                   /* Clear all properties.  */
 136                   elf_properties (abfd) = NULL;
 137                   return false;
 138                 }
 139               else if (kind != property_ignored)
 140                 goto next;
 141             }
 142         }
 143       else
 144         {
 145           switch (type)
 146             {
 147             case GNU_PROPERTY_STACK_SIZE:
 148               if (datasz != align_size)
 149                 {
 150                   _bfd_error_handler
 151                     (_("warning: %pB: corrupt stack size: 0x%x"),
 152                      abfd, datasz);
 153                   /* Clear all properties.  */
 154                   elf_properties (abfd) = NULL;
 155                   return false;
 156                 }
 157               prop = _bfd_elf_get_property (abfd, type, datasz);
 158               if (datasz == 8)
 159                 prop->u.number = bfd_h_get_64 (abfd, ptr);
 160               else
 161                 prop->u.number = bfd_h_get_32 (abfd, ptr);
 162               prop->pr_kind = property_number;
 163               goto next;
 164
 165             case GNU_PROPERTY_NO_COPY_ON_PROTECTED:
 166               if (datasz != 0)
 167                 {
 168                   _bfd_error_handler
 169                     (_("warning: %pB: corrupt no copy on protected size: 0x%x"),
 170                      abfd, datasz);
 171                   /* Clear all properties.  */
 172                   elf_properties (abfd) = NULL;
 173                   return false;
 174                 }
 175               prop = _bfd_elf_get_property (abfd, type, datasz);
 176               elf_has_no_copy_on_protected (abfd) = true;
 177               prop->pr_kind = property_number;
 178               goto next;
 179
 180             case GNU_PROPERTY_MEMORY_SEAL:
 181               if (datasz != 0)
 182                 {
 183                   _bfd_error_handler
 184                     (_("warning: %pB: corrupt memory sealing size: 0x%x"),
 185                      abfd, datasz);
 186                   /* Clear all properties.  */
 187                   elf_properties (abfd) = NULL;
 188                   return false;
 189                 }
 190               prop = _bfd_elf_get_property (abfd, type, datasz);
 191               prop->pr_kind = property_number;
 192               goto next;
 193
 194             default:
 195               if ((type >= GNU_PROPERTY_UINT32_AND_LO
 196                    && type <= GNU_PROPERTY_UINT32_AND_HI)
 197                   || (type >= GNU_PROPERTY_UINT32_OR_LO
 198                       && type <= GNU_PROPERTY_UINT32_OR_HI))
 199                 {
 200                   if (datasz != 4)
 201                     {
 202                       _bfd_error_handler
 203                         (_("error: %pB: <corrupt property (0x%x) size: 0x%x>"),
 204                          abfd, type, datasz);
 205                       /* Clear all properties.  */
 206                       elf_properties (abfd) = NULL;
 207                       return false;
 208                     }
 209                   prop = _bfd_elf_get_property (abfd, type, datasz);
 210                   prop->u.number |= bfd_h_get_32 (abfd, ptr);
 211                   prop->pr_kind = property_number;
 212                   if (type == GNU_PROPERTY_1_NEEDED
 213                       && ((prop->u.number
 214                            & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)
 215                           != 0))
 216                     {
 217                       elf_has_indirect_extern_access (abfd) = true;
 218                       /* GNU_PROPERTY_NO_COPY_ON_PROTECTED is implied.  */
 219                       elf_has_no_copy_on_protected (abfd) = true;
 220                     }
 221                   goto next;
 222                 }
 223               break;
 224             }
 225         }
 226
 227       _bfd_error_handler
 228         (_("warning: %pB: unsupported GNU_PROPERTY_TYPE (%ld) type: 0x%x"),
 229          abfd, note->type, type);
 230
 231     next:
 232       ptr += (datasz + (align_size - 1)) & ~ (align_size - 1);
 233     }
 234
 235   return true;
 236 }
 237
 238 /* Merge GNU property BPROP with APROP.  If APROP isn't NULL, return TRUE
 239    if APROP is updated.  Otherwise, return TRUE if BPROP should be merged
 240    with ABFD.  */
 241
 242 static bool
 243 elf_merge_gnu_properties (struct bfd_link_info *info, bfd *abfd, bfd *bbfd,
 244                           elf_property *aprop, elf_property *bprop)
 245 {
 246   const struct elf_backend_data *bed = get_elf_backend_data (abfd);
 247   unsigned int pr_type = aprop != NULL ? aprop->pr_type : bprop->pr_type;
 248   unsigned int number;
 249   bool updated;
 250
 251   if (bed->merge_gnu_properties != NULL
 252       && pr_type >= GNU_PROPERTY_LOPROC
 253       && pr_type < GNU_PROPERTY_LOUSER)
 254     return bed->merge_gnu_properties (info, abfd, bbfd, aprop, bprop);
 255
 256   switch (pr_type)
 257     {
 258     case GNU_PROPERTY_STACK_SIZE:
 259       if (aprop != NULL && bprop != NULL)
 260         {
 261           if (bprop->u.number > aprop->u.number)
 262             {
 263               aprop->u.number = bprop->u.number;
 264               return true;
 265             }
 266           break;
 267         }
 268       /* FALLTHROUGH */
 269
 270     case GNU_PROPERTY_NO_COPY_ON_PROTECTED:
 271     case GNU_PROPERTY_MEMORY_SEAL:
 272       /* Return TRUE if APROP is NULL to indicate that BPROP should
 273          be added to ABFD.  */
 274       return aprop == NULL;
 275
 276     default:
 277       updated = false;
 278       if (pr_type >= GNU_PROPERTY_UINT32_OR_LO
 279           && pr_type <= GNU_PROPERTY_UINT32_OR_HI)
 280         {
 281           if (aprop != NULL && bprop != NULL)
 282             {
 283               number = aprop->u.number;
 284               aprop->u.number = number | bprop->u.number;
 285               /* Remove the property if all bits are empty.  */
 286               if (aprop->u.number == 0)
 287                 {
 288                   aprop->pr_kind = property_remove;
 289                   updated = true;
 290                 }
 291               else
 292                 updated = number != (unsigned int) aprop->u.number;
 293             }
 294           else
 295             {
 296               /* Only one of APROP and BPROP can be NULL.  */
 297               if (aprop != NULL)
 298                 {
 299                   if (aprop->u.number == 0)
 300                     {
 301                       /* Remove APROP if all bits are empty.  */
 302                       aprop->pr_kind = property_remove;
 303                       updated = true;
 304                     }
 305                 }
 306               else
 307                 {
 308                   /* Return TRUE if APROP is NULL and all bits of BPROP
 309                      aren't empty to indicate that BPROP should be added
 310                      to ABFD.  */
 311                   updated = bprop->u.number != 0;
 312                 }
 313             }
 314           return updated;
 315         }
 316       else if (pr_type >= GNU_PROPERTY_UINT32_AND_LO
 317                && pr_type <= GNU_PROPERTY_UINT32_AND_HI)
 318         {
 319           /* Only one of APROP and BPROP can be NULL:
 320              1. APROP & BPROP when both APROP and BPROP aren't NULL.
 321              2. If APROP is NULL, remove x86 feature.
 322              3. Otherwise, do nothing.
 323              */
 324           if (aprop != NULL && bprop != NULL)
 325             {
 326               number = aprop->u.number;
 327               aprop->u.number = number & bprop->u.number;
 328               updated = number != (unsigned int) aprop->u.number;
 329               /* Remove the property if all feature bits are cleared.  */
 330               if (aprop->u.number == 0)
 331                 aprop->pr_kind = property_remove;
 332             }
 333           else
 334             {
 335               /* There should be no AND properties since some input
 336                  doesn't have them.   */
 337               if (aprop != NULL)
 338                 {
 339                   aprop->pr_kind = property_remove;
 340                   updated = true;
 341                 }
 342             }
 343           return updated;
 344         }
 345
 346       /* Never should happen.  */
 347       abort ();
 348     }
 349
 350   return false;
 351 }
 352
 353 /* Return the property of TYPE on *LISTP and remove it from *LISTP if RM is
 354    true.  Return NULL if not found.  */
 355
 356 static elf_property *
 357 elf_find_and_remove_property (elf_property_list **listp,
 358                               unsigned int type, bool rm)
 359 {
 360   elf_property_list *list;
 361
 362   for (list = *listp; list; list = list->next)
 363     {
 364       if (type == list->property.pr_type)
 365         {
 366           /* Remove this property.  */
 367           if (rm)
 368             *listp = list->next;
 369           return &list->property;
 370         }
 371       else if (type < list->property.pr_type)
 372         break;
 373       listp = &list->next;
 374     }
 375
 376   return NULL;
 377 }
 378
 379 /* Merge GNU property list *LISTP in ABFD with FIRST_PBFD.  */
 380
 381 static void
 382 elf_merge_gnu_property_list (struct bfd_link_info *info, bfd *first_pbfd,
 383                              bfd *abfd, elf_property_list **listp)
 384 {
 385   elf_property_list *p, **lastp;
 386   elf_property *pr;
 387   bool number_p;
 388   bfd_vma number = 0;
 389
 390   /* Merge each GNU property in FIRST_PBFD with the one on *LISTP.  */
 391   lastp = &elf_properties (first_pbfd);
 392   for (p = *lastp; p; p = p->next)
 393     if (p->property.pr_kind != property_remove)
 394       {
 395         if (p->property.pr_kind == property_number)
 396           {
 397             number_p = true;
 398             number = p->property.u.number;
 399           }
 400         else
 401           number_p = false;
 402         pr = elf_find_and_remove_property (listp, p->property.pr_type,
 403                                            true);
 404         /* Pass NULL to elf_merge_gnu_properties for the property which
 405            isn't on *LISTP.  */
 406         elf_merge_gnu_properties (info, first_pbfd, abfd, &p->property, pr);
 407         if (p->property.pr_kind == property_remove)
 408           {
 409             if (info->has_map_file)
 410               {
 411                 if (number_p)
 412                   {
 413                     if (pr != NULL)
 414                       info->callbacks->minfo
 415                         (_("Removed property %W to merge %pB (0x%v) "
 416                            "and %pB (0x%v)\n"),
 417                          (bfd_vma) p->property.pr_type, first_pbfd,
 418                          number, abfd, pr->u.number);
 419                     else
 420                       info->callbacks->minfo
 421                         (_("Removed property %W to merge %pB (0x%v) "
 422                            "and %pB (not found)\n"),
 423                          (bfd_vma) p->property.pr_type, first_pbfd,
 424                          number, abfd);
 425                   }
 426                 else
 427                   {
 428                     if (pr != NULL)
 429                       info->callbacks->minfo
 430                         (_("Removed property %W to merge %pB and %pB\n"),
 431                          (bfd_vma) p->property.pr_type, first_pbfd, abfd);
 432                     else
 433                       info->callbacks->minfo
 434                         (_("Removed property %W to merge %pB and %pB "
 435                            "(not found)\n"),
 436                          (bfd_vma) p->property.pr_type, first_pbfd, abfd);
 437                   }
 438               }
 439
 440             /* Remove this property.  */
 441             *lastp = p->next;
 442             continue;
 443           }
 444         else if (number_p)
 445           {
 446             if (pr != NULL)
 447               {
 448                 if (p->property.u.number != number
 449                     || p->property.u.number != pr->u.number)
 450                   info->callbacks->minfo
 451                     (_("Updated property %W (0x%v) to merge %pB (0x%v) "
 452                        "and %pB (0x%v)\n"),
 453                      (bfd_vma) p->property.pr_type, p->property.u.number,
 454                      first_pbfd, number, abfd, pr->u.number);
 455               }
 456             else
 457               {
 458                 if (p->property.u.number != number)
 459                   info->callbacks->minfo
 460                     (_("Updated property %W (%v) to merge %pB (0x%v) "
 461                        "and %pB (not found)\n"),
 462                      (bfd_vma) p->property.pr_type, p->property.u.number,
 463                      first_pbfd, number, abfd);
 464               }
 465           }
 466         lastp = &p->next;
 467       }
 468
 469   /* Merge the remaining properties on *LISTP with FIRST_PBFD.  */
 470   for (p = *listp; p != NULL; p = p->next)
 471     {
 472       if (p->property.pr_kind == property_number)
 473         {
 474           number_p = true;
 475           number = p->property.u.number;
 476         }
 477       else
 478         number_p = false;
 479
 480       if (elf_merge_gnu_properties (info, first_pbfd, abfd, NULL, &p->property))
 481         {
 482           if (p->property.pr_type == GNU_PROPERTY_NO_COPY_ON_PROTECTED)
 483             elf_has_no_copy_on_protected (first_pbfd) = true;
 484
 485           pr = _bfd_elf_get_property (first_pbfd, p->property.pr_type,
 486                                       p->property.pr_datasz);
 487           /* It must be a new property.  */
 488           if (pr->pr_kind != property_unknown)
 489             abort ();
 490           /* Add a new property.  */
 491           *pr = p->property;
 492         }
 493       else
 494         {
 495           pr = elf_find_and_remove_property (&elf_properties (first_pbfd),
 496                                              p->property.pr_type,
 497                                              false);
 498           if (pr == NULL)
 499             {
 500               if (number_p)
 501                 info->callbacks->minfo
 502                   (_("Removed property %W to merge %pB (not found) and "
 503                      "%pB (0x%v)\n"),
 504                    (bfd_vma) p->property.pr_type, first_pbfd, abfd,
 505                    number);
 506               else
 507                 info->callbacks->minfo
 508                   (_("Removed property %W to merge %pB and %pB\n"),
 509                    (bfd_vma) p->property.pr_type, first_pbfd, abfd);
 510             }
 511           else if (pr->pr_kind != property_remove)
 512             abort ();
 513         }
 514     }
 515 }
 516
 517 /* Get GNU property section size.  */
 518
 519 static bfd_size_type
 520 elf_get_gnu_property_section_size (elf_property_list *list,
 521                                    unsigned int align_size)
 522 {
 523   bfd_size_type size;
 524   unsigned int descsz;
 525
 526   /* Compute the output section size.  */
 527   descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]);
 528   descsz = (descsz + 3) & -(unsigned int) 4;
 529   size = descsz;
 530   for (; list != NULL; list = list->next)
 531     {
 532       unsigned int datasz;
 533       /* Check if this property should be skipped.  */
 534       if (list->property.pr_kind == property_remove)
 535         continue;
 536       /* There are 4 byte type + 4 byte datasz for each property.  */
 537       if (list->property.pr_type == GNU_PROPERTY_STACK_SIZE)
 538         datasz = align_size;
 539       else
 540         datasz = list->property.pr_datasz;
 541       size += 4 + 4 + datasz;
 542       /* Align each property.  */
 543       size = (size + (align_size - 1)) & ~(align_size - 1);
 544     }
 545
 546   return size;
 547 }
 548
 549 /* Write GNU properties.  */
 550
 551 static void
 552 elf_write_gnu_properties (struct bfd_link_info *info,
 553                           bfd *abfd, bfd_byte *contents,
 554                           elf_property_list *list, unsigned int size,
 555                           unsigned int align_size)
 556 {
 557   unsigned int descsz;
 558   unsigned int datasz;
 559   Elf_External_Note *e_note;
 560
 561   e_note = (Elf_External_Note *) contents;
 562   descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]);
 563   descsz = (descsz + 3) & -(unsigned int) 4;
 564   bfd_h_put_32 (abfd, sizeof "GNU", &e_note->namesz);
 565   bfd_h_put_32 (abfd, size - descsz, &e_note->descsz);
 566   bfd_h_put_32 (abfd, NT_GNU_PROPERTY_TYPE_0, &e_note->type);
 567   memcpy (e_note->name, "GNU", sizeof "GNU");
 568
 569   size = descsz;
 570   for (; list != NULL; list = list->next)
 571     {
 572       /* Check if this property should be skipped.  */
 573       if (list->property.pr_kind == property_remove)
 574         continue;
 575       /* There are 4 byte type + 4 byte datasz for each property.  */
 576       if (list->property.pr_type == GNU_PROPERTY_STACK_SIZE)
 577         datasz = align_size;
 578       else
 579         datasz = list->property.pr_datasz;
 580       bfd_h_put_32 (abfd, list->property.pr_type, contents + size);
 581       bfd_h_put_32 (abfd, datasz, contents + size + 4);
 582       size += 4 + 4;
 583
 584       /* Write out property value.  */
 585       switch (list->property.pr_kind)
 586         {
 587         case property_number:
 588           switch (datasz)
 589             {
 590             default:
 591               /* Never should happen.  */
 592               abort ();
 593
 594             case 0:
 595               break;
 596
 597             case 4:
 598               /* Save the pointer to GNU_PROPERTY_1_NEEDED so that it
 599                  can be updated later if needed.  */
 600               if (info != NULL
 601                   && list->property.pr_type == GNU_PROPERTY_1_NEEDED)
 602                 info->needed_1_p = contents + size;
 603               bfd_h_put_32 (abfd, list->property.u.number,
 604                             contents + size);
 605               break;
 606
 607             case 8:
 608               bfd_h_put_64 (abfd, list->property.u.number,
 609                             contents + size);
 610               break;
 611             }
 612           break;
 613
 614         default:
 615           /* Never should happen.  */
 616           abort ();
 617         }
 618       size += datasz;
 619
 620       /* Align each property.  */
 621       size = (size + (align_size - 1)) & ~ (align_size - 1);
 622     }
 623 }
 624
 625 static asection *
 626 _bfd_elf_link_create_gnu_property_sec (struct bfd_link_info *info, bfd *elf_bfd,
 627                                        unsigned int elfclass)
 628 {
 629   asection *sec;
 630
 631   sec = bfd_make_section_with_flags (elf_bfd,
 632                                      NOTE_GNU_PROPERTY_SECTION_NAME,
 633                                      (SEC_ALLOC
 634                                       | SEC_LOAD
 635                                       | SEC_IN_MEMORY
 636                                       | SEC_READONLY
 637                                       | SEC_HAS_CONTENTS
 638                                       | SEC_DATA));
 639   if (sec == NULL)
 640     info->callbacks->einfo (_("%F%P: failed to create GNU property section\n"));
 641
 642   if (!bfd_set_section_alignment (sec,
 643                                   elfclass == ELFCLASS64 ? 3 : 2))
 644     info->callbacks->einfo (_("%F%pA: failed to align section\n"),
 645                             sec);
 646
 647   elf_section_type (sec) = SHT_NOTE;
 648   return sec;
 649 }
 650
 651
 652 /* Set up GNU properties.  Return the first relocatable ELF input with
 653    GNU properties if found.  Otherwise, return NULL.  */
 654
 655 bfd *
 656 _bfd_elf_link_setup_gnu_properties (struct bfd_link_info *info)
 657 {
 658   bfd *abfd, *first_pbfd = NULL, *elf_bfd = NULL;
 659   elf_property_list *list;
 660   asection *sec;
 661   bool has_properties = false;
 662   const struct elf_backend_data *bed
 663     = get_elf_backend_data (info->output_bfd);
 664   unsigned int elfclass = bed->s->elfclass;
 665   int elf_machine_code = bed->elf_machine_code;
 666   elf_property *p;
 667
 668   /* Find the first relocatable ELF input with GNU properties.  */
 669   for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
 670     if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
 671         && (abfd->flags & DYNAMIC) == 0
 672         && (elf_machine_code
 673             == get_elf_backend_data (abfd)->elf_machine_code)
 674         && (elfclass == get_elf_backend_data (abfd)->s->elfclass))
 675       {
 676         /* Ignore GNU properties from ELF objects with different machine
 677            code or class.  Also skip objects without a GNU_PROPERTY note
 678            section.  */
 679         elf_bfd = abfd;
 680
 681         if (elf_properties (abfd) != NULL)
 682           {
 683             has_properties = true;
 684
 685             if (bfd_get_section_by_name (abfd,
 686                                          NOTE_GNU_PROPERTY_SECTION_NAME)
 687                 != NULL)
 688               {
 689                 /* Keep .note.gnu.property section in FIRST_PBFD.  */
 690                 first_pbfd = abfd;
 691                 break;
 692               }
 693           }
 694       }
 695
 696   if (info->indirect_extern_access > 0 && elf_bfd != NULL)
 697     {
 698       /* Support -z indirect-extern-access.  */
 699       if (first_pbfd == NULL)
 700         {
 701           sec = _bfd_elf_link_create_gnu_property_sec (info, elf_bfd, elfclass);
 702           first_pbfd = elf_bfd;
 703           has_properties = true;
 704         }
 705
 706       p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_1_NEEDED, 4);
 707       if (p->pr_kind == property_unknown)
 708         {
 709           /* Create GNU_PROPERTY_1_NEEDED.  */
 710           p->u.number
 711             = GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
 712           p->pr_kind = property_number;
 713         }
 714       else
 715         p->u.number
 716           |= GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
 717     }
 718
 719   if (elf_bfd != NULL)
 720     {
 721       if (info->memory_seal)
 722         {
 723           /* Support -z no-memory-seal.  */
 724           if (first_pbfd == NULL)
 725             {
 726               sec = _bfd_elf_link_create_gnu_property_sec (info, elf_bfd, elfclass);
 727               first_pbfd = elf_bfd;
 728               has_properties = true;
 729             }
 730
 731           p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_MEMORY_SEAL, 0);
 732           if (p->pr_kind == property_unknown)
 733             {
 734               /* Create GNU_PROPERTY_NO_MEMORY_SEAL.  */
 735               p->u.number = GNU_PROPERTY_MEMORY_SEAL;
 736               p->pr_kind = property_number;
 737             }
 738         }
 739       else
 740         elf_find_and_remove_property (&elf_properties (elf_bfd),
 741                                       GNU_PROPERTY_MEMORY_SEAL, true);
 742     }
 743
 744   /* Do nothing if there is no .note.gnu.property section.  */
 745   if (!has_properties)
 746     return NULL;
 747
 748   /* Merge .note.gnu.property sections.  */
 749   info->callbacks->minfo (_("\n"));
 750   info->callbacks->minfo (_("Merging program properties\n"));
 751   info->callbacks->minfo (_("\n"));
 752
 753   for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next)
 754     if (abfd != first_pbfd
 755         && (abfd->flags & (DYNAMIC | BFD_PLUGIN | BFD_LINKER_CREATED)) == 0)
 756       {
 757         elf_property_list *null_ptr = NULL;
 758         elf_property_list **listp = &null_ptr;
 759
 760         /* Merge .note.gnu.property section in relocatable ELF input.  */
 761         if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
 762           {
 763             list = elf_properties (abfd);
 764
 765             /* Ignore GNU properties from ELF objects with different
 766                machine code.  */
 767             if (list != NULL
 768                 && (elf_machine_code
 769                     == get_elf_backend_data (abfd)->elf_machine_code))
 770               listp = &elf_properties (abfd);
 771           }
 772         else
 773           list = NULL;
 774
 775         /* Merge properties with FIRST_PBFD.  FIRST_PBFD can be NULL
 776            when all properties are from ELF objects with different
 777            machine code or class.  */
 778         if (first_pbfd != NULL)
 779           elf_merge_gnu_property_list (info, first_pbfd, abfd, listp);
 780
 781         if (list != NULL)
 782           {
 783             /* Discard the .note.gnu.property section in this bfd.  */
 784             sec = bfd_get_section_by_name (abfd,
 785                                            NOTE_GNU_PROPERTY_SECTION_NAME);
 786             if (sec != NULL)
 787               sec->output_section = bfd_abs_section_ptr;
 788           }
 789       }
 790
 791   /* Rewrite .note.gnu.property section so that GNU properties are
 792      always sorted by type even if input GNU properties aren't sorted.  */
 793   if (first_pbfd != NULL)
 794     {
 795       bfd_size_type size;
 796       bfd_byte *contents;
 797       unsigned int align_size = elfclass == ELFCLASS64 ? 8 : 4;
 798
 799       sec = bfd_get_section_by_name (first_pbfd,
 800                                      NOTE_GNU_PROPERTY_SECTION_NAME);
 801       BFD_ASSERT (sec != NULL);
 802
 803       /* Update stack size in .note.gnu.property with -z stack-size=N
 804          if N > 0.  */
 805       if (info->stacksize > 0)
 806         {
 807           bfd_vma stacksize = info->stacksize;
 808
 809           p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_STACK_SIZE,
 810                                      align_size);
 811           if (p->pr_kind == property_unknown)
 812             {
 813               /* Create GNU_PROPERTY_STACK_SIZE.  */
 814               p->u.number = stacksize;
 815               p->pr_kind = property_number;
 816             }
 817           else if (stacksize > p->u.number)
 818             p->u.number = stacksize;
 819         }
 820       else if (elf_properties (first_pbfd) == NULL)
 821         {
 822           /* Discard .note.gnu.property section if all properties have
 823              been removed.  */
 824           sec->output_section = bfd_abs_section_ptr;
 825           return NULL;
 826         }
 827
 828       /* Fix up GNU properties.  */
 829       if (bed->fixup_gnu_properties)
 830         bed->fixup_gnu_properties (info, &elf_properties (first_pbfd));
 831
 832       if (elf_properties (first_pbfd) == NULL)
 833         {
 834           /* Discard .note.gnu.property section if all properties have
 835              been removed.  */
 836           sec->output_section = bfd_abs_section_ptr;
 837           return NULL;
 838         }
 839
 840       /* Compute the section size.  */
 841       list = elf_properties (first_pbfd);
 842       size = elf_get_gnu_property_section_size (list, align_size);
 843
 844       /* Update .note.gnu.property section now.  */
 845       sec->size = size;
 846       contents = (bfd_byte *) bfd_zalloc (first_pbfd, size);
 847
 848       if (info->indirect_extern_access <= 0)
 849         {
 850           /* Get GNU_PROPERTY_1_NEEDED properties.  */
 851           p = elf_find_and_remove_property (&elf_properties (first_pbfd),
 852                                             GNU_PROPERTY_1_NEEDED, false);
 853           if (p != NULL)
 854             {
 855               if (info->indirect_extern_access < 0)
 856                 {
 857                   /* Set indirect_extern_access to 1 to indicate that
 858                      it is turned on by input properties.  */
 859                   if ((p->u.number
 860                        & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)
 861                       != 0)
 862                     info->indirect_extern_access = 1;
 863                 }
 864               else
 865                 /* Turn off indirect external access.  */
 866                 p->u.number
 867                   &= ~GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS;
 868             }
 869         }
 870
 871       elf_write_gnu_properties (info, first_pbfd, contents, list, size,
 872                                 align_size);
 873
 874       /* Cache the section contents for elf_link_input_bfd.  */
 875       sec->alloced = 1;
 876       elf_section_data (sec)->this_hdr.contents = contents;
 877
 878       /* If GNU_PROPERTY_NO_COPY_ON_PROTECTED is set, protected data
 879          symbol is defined in the shared object.  */
 880       if (elf_has_no_copy_on_protected (first_pbfd))
 881         info->extern_protected_data = false;
 882
 883       if (info->indirect_extern_access > 0)
 884         {
 885           /* For indirect external access, don't generate copy
 886              relocations.  NB: Set to nocopyreloc to 2 to indicate
 887              that it is implied by indirect_extern_access.  */
 888           info->nocopyreloc = 2;
 889           info->extern_protected_data = false;
 890         }
 891     }
 892
 893   return first_pbfd;
 894 }
 895
 896 /* Convert GNU property size.  */
 897
 898 bfd_size_type
 899 _bfd_elf_convert_gnu_property_size (bfd *ibfd, bfd *obfd)
 900 {
 901   unsigned int align_size;
 902   const struct elf_backend_data *bed;
 903   elf_property_list *list = elf_properties (ibfd);
 904
 905   bed = get_elf_backend_data (obfd);
 906   align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4;
 907
 908   /* Get the output .note.gnu.property section size.  */
 909   return elf_get_gnu_property_section_size (list, align_size);
 910 }
 911
 912 /* Convert GNU properties.  */
 913
 914 bool
 915 _bfd_elf_convert_gnu_properties (bfd *ibfd, asection *isec,
 916                                  bfd *obfd, bfd_byte **ptr,
 917                                  bfd_size_type *ptr_size)
 918 {
 919   unsigned int size;
 920   bfd_byte *contents;
 921   unsigned int align_shift;
 922   const struct elf_backend_data *bed;
 923   elf_property_list *list = elf_properties (ibfd);
 924
 925   bed = get_elf_backend_data (obfd);
 926   align_shift = bed->s->elfclass == ELFCLASS64 ? 3 : 2;
 927
 928   /* Get the output .note.gnu.property section size.  */
 929   size = bfd_section_size (isec->output_section);
 930
 931   /* Update the output .note.gnu.property section alignment.  */
 932   bfd_set_section_alignment (isec->output_section, align_shift);
 933
 934   if (size > bfd_section_size (isec))
 935     {
 936       contents = (bfd_byte *) bfd_malloc (size);
 937       if (contents == NULL)
 938         return false;
 939       free (*ptr);
 940       *ptr = contents;
 941     }
 942   else
 943     contents = *ptr;
 944
 945   *ptr_size = size;
 946
 947   /* Generate the output .note.gnu.property section.  */
 948   elf_write_gnu_properties (NULL, ibfd, contents, list, size,
 949                             1 << align_shift);
 950
 951   return true;
 952 }