Commit | Line | Data |
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46bed679 | 1 | /* ELF program property support. |
219d1afa | 2 | Copyright (C) 2017-2018 Free Software Foundation, Inc. |
46bed679 L |
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 | { | |
871b3ab2 | 65 | _bfd_error_handler (_("%pB: out of memory in _bfd_elf_get_property"), |
46bed679 L |
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 | |
871b3ab2 | 91 | (_("warning: %pB: corrupt GNU_PROPERTY_TYPE (%ld) size: %#lx"), |
46bed679 L |
92 | abfd, note->type, note->descsz); |
93 | return FALSE; | |
94 | } | |
95 | ||
cf54ebff | 96 | while (ptr != ptr_end) |
46bed679 | 97 | { |
cf54ebff AM |
98 | unsigned int type; |
99 | unsigned int datasz; | |
46bed679 L |
100 | elf_property *prop; |
101 | ||
cf54ebff AM |
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); | |
46bed679 L |
107 | ptr += 8; |
108 | ||
cf54ebff | 109 | if (datasz > (size_t) (ptr_end - ptr)) |
46bed679 L |
110 | { |
111 | _bfd_error_handler | |
871b3ab2 | 112 | (_("warning: %pB: corrupt GNU_PROPERTY_TYPE (%ld) type (0x%x) datasz: 0x%x"), |
46bed679 L |
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 | { | |
537616aa L |
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) | |
46bed679 L |
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 | |
871b3ab2 | 151 | (_("warning: %pB: corrupt stack size: 0x%x"), |
46bed679 L |
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 | |
871b3ab2 | 169 | (_("warning: %pB: corrupt no copy on protected size: 0x%x"), |
46bed679 L |
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); | |
a5b4ee94 | 176 | elf_has_no_copy_on_protected (abfd) = TRUE; |
46bed679 L |
177 | prop->pr_kind = property_number; |
178 | goto next; | |
179 | ||
180 | default: | |
181 | break; | |
182 | } | |
183 | } | |
184 | ||
185 | _bfd_error_handler | |
871b3ab2 | 186 | (_("warning: %pB: unsupported GNU_PROPERTY_TYPE (%ld) type: 0x%x"), |
46bed679 L |
187 | abfd, note->type, type); |
188 | ||
189 | next: | |
190 | ptr += (datasz + (align_size - 1)) & ~ (align_size - 1); | |
46bed679 L |
191 | } |
192 | ||
193 | return TRUE; | |
194 | } | |
195 | ||
196 | /* Merge GNU property BPROP with APROP. If APROP isn't NULL, return TRUE | |
197 | if APROP is updated. Otherwise, return TRUE if BPROP should be merged | |
198 | with ABFD. */ | |
199 | ||
200 | static bfd_boolean | |
5c3ce2bc L |
201 | elf_merge_gnu_properties (struct bfd_link_info *info, bfd *abfd, |
202 | elf_property *aprop, elf_property *bprop) | |
46bed679 L |
203 | { |
204 | const struct elf_backend_data *bed = get_elf_backend_data (abfd); | |
205 | unsigned int pr_type = aprop != NULL ? aprop->pr_type : bprop->pr_type; | |
206 | ||
207 | if (bed->merge_gnu_properties != NULL | |
208 | && pr_type >= GNU_PROPERTY_LOPROC | |
209 | && pr_type < GNU_PROPERTY_LOUSER) | |
5c3ce2bc | 210 | return bed->merge_gnu_properties (info, abfd, aprop, bprop); |
46bed679 L |
211 | |
212 | switch (pr_type) | |
213 | { | |
214 | case GNU_PROPERTY_STACK_SIZE: | |
215 | if (aprop != NULL && bprop != NULL) | |
216 | { | |
217 | if (bprop->u.number > aprop->u.number) | |
218 | { | |
219 | aprop->u.number = bprop->u.number; | |
220 | return TRUE; | |
221 | } | |
222 | break; | |
223 | } | |
224 | /* FALLTHROUGH */ | |
225 | ||
226 | case GNU_PROPERTY_NO_COPY_ON_PROTECTED: | |
227 | /* Return TRUE if APROP is NULL to indicate that BPROP should | |
228 | be added to ABFD. */ | |
229 | return aprop == NULL; | |
230 | ||
231 | default: | |
232 | /* Never should happen. */ | |
233 | abort (); | |
234 | } | |
235 | ||
236 | return FALSE; | |
237 | } | |
238 | ||
239 | /* Return the property of TYPE on *LISTP and remove it from *LISTP. | |
240 | Return NULL if not found. */ | |
241 | ||
242 | static elf_property * | |
243 | elf_find_and_remove_property (elf_property_list **listp, | |
244 | unsigned int type) | |
245 | { | |
246 | elf_property_list *list; | |
247 | ||
248 | for (list = *listp; list; list = list->next) | |
249 | { | |
250 | if (type == list->property.pr_type) | |
251 | { | |
252 | /* Remove this property. */ | |
253 | *listp = list->next; | |
254 | return &list->property; | |
255 | } | |
256 | else if (type < list->property.pr_type) | |
257 | break; | |
258 | listp = &list->next; | |
259 | } | |
260 | ||
261 | return NULL; | |
262 | } | |
263 | ||
264 | /* Merge GNU property list *LISTP with ABFD. */ | |
265 | ||
266 | static void | |
5c3ce2bc L |
267 | elf_merge_gnu_property_list (struct bfd_link_info *info, bfd *abfd, |
268 | elf_property_list **listp) | |
46bed679 L |
269 | { |
270 | elf_property_list *p, **lastp; | |
271 | elf_property *pr; | |
272 | ||
273 | /* Merge each GNU property in ABFD with the one on *LISTP. */ | |
274 | lastp = &elf_properties (abfd); | |
275 | for (p = *lastp; p; p = p->next) | |
276 | { | |
277 | pr = elf_find_and_remove_property (listp, p->property.pr_type); | |
278 | /* Pass NULL to elf_merge_gnu_properties for the property which | |
279 | isn't on *LISTP. */ | |
5c3ce2bc | 280 | elf_merge_gnu_properties (info, abfd, &p->property, pr); |
46bed679 L |
281 | if (p->property.pr_kind == property_remove) |
282 | { | |
283 | /* Remove this property. */ | |
284 | *lastp = p->next; | |
285 | continue; | |
286 | } | |
287 | lastp = &p->next; | |
288 | } | |
289 | ||
290 | /* Merge the remaining properties on *LISTP with ABFD. */ | |
291 | for (p = *listp; p != NULL; p = p->next) | |
5c3ce2bc | 292 | if (elf_merge_gnu_properties (info, abfd, NULL, &p->property)) |
46bed679 | 293 | { |
a5b4ee94 L |
294 | if (p->property.pr_type == GNU_PROPERTY_NO_COPY_ON_PROTECTED) |
295 | elf_has_no_copy_on_protected (abfd) = TRUE; | |
296 | ||
46bed679 L |
297 | pr = _bfd_elf_get_property (abfd, p->property.pr_type, |
298 | p->property.pr_datasz); | |
299 | /* It must be a new property. */ | |
300 | if (pr->pr_kind != property_unknown) | |
301 | abort (); | |
302 | /* Add a new property. */ | |
303 | *pr = p->property; | |
304 | } | |
305 | } | |
306 | ||
fba37edd L |
307 | /* Set up GNU properties. Return the first relocatable ELF input with |
308 | GNU properties if found. Otherwise, return NULL. */ | |
46bed679 | 309 | |
fba37edd | 310 | bfd * |
46bed679 L |
311 | _bfd_elf_link_setup_gnu_properties (struct bfd_link_info *info) |
312 | { | |
313 | bfd *abfd, *first_pbfd = NULL; | |
314 | elf_property_list *list; | |
315 | asection *sec; | |
316 | bfd_boolean has_properties = FALSE; | |
317 | const struct elf_backend_data *bed | |
318 | = get_elf_backend_data (info->output_bfd); | |
319 | unsigned int elfclass = bed->s->elfclass; | |
320 | int elf_machine_code = bed->elf_machine_code; | |
321 | ||
322 | /* Find the first relocatable ELF input with GNU properties. */ | |
323 | for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next) | |
324 | if (bfd_get_flavour (abfd) == bfd_target_elf_flavour | |
abfa390d | 325 | && (abfd->flags & DYNAMIC) == 0 |
46bed679 L |
326 | && elf_properties (abfd) != NULL) |
327 | { | |
328 | has_properties = TRUE; | |
329 | ||
330 | /* Ignore GNU properties from ELF objects with different machine | |
b77db948 NC |
331 | code or class. Also skip objects without a GNU_PROPERTY note |
332 | section. */ | |
46bed679 L |
333 | if ((elf_machine_code |
334 | == get_elf_backend_data (abfd)->elf_machine_code) | |
335 | && (elfclass | |
b77db948 NC |
336 | == get_elf_backend_data (abfd)->s->elfclass) |
337 | && bfd_get_section_by_name (abfd, | |
338 | NOTE_GNU_PROPERTY_SECTION_NAME) != NULL | |
339 | ) | |
46bed679 L |
340 | { |
341 | /* Keep .note.gnu.property section in FIRST_PBFD. */ | |
342 | first_pbfd = abfd; | |
343 | break; | |
344 | } | |
345 | } | |
346 | ||
347 | /* Do nothing if there is no .note.gnu.property section. */ | |
348 | if (!has_properties) | |
fba37edd | 349 | return NULL; |
46bed679 L |
350 | |
351 | /* Merge .note.gnu.property sections. */ | |
352 | for (abfd = info->input_bfds; abfd != NULL; abfd = abfd->link.next) | |
abfa390d | 353 | if (abfd != first_pbfd && (abfd->flags & DYNAMIC) == 0) |
46bed679 L |
354 | { |
355 | elf_property_list *null_ptr = NULL; | |
356 | elf_property_list **listp = &null_ptr; | |
357 | ||
358 | /* Merge .note.gnu.property section in relocatable ELF input. */ | |
359 | if (bfd_get_flavour (abfd) == bfd_target_elf_flavour) | |
360 | { | |
361 | list = elf_properties (abfd); | |
362 | ||
363 | /* Ignore GNU properties from ELF objects with different | |
364 | machine code. */ | |
365 | if (list != NULL | |
366 | && (elf_machine_code | |
367 | == get_elf_backend_data (abfd)->elf_machine_code)) | |
368 | listp = &elf_properties (abfd); | |
369 | } | |
370 | else | |
371 | list = NULL; | |
372 | ||
373 | /* Merge properties with FIRST_PBFD. FIRST_PBFD can be NULL | |
374 | when all properties are from ELF objects with different | |
375 | machine code or class. */ | |
376 | if (first_pbfd != NULL) | |
5c3ce2bc | 377 | elf_merge_gnu_property_list (info, first_pbfd, listp); |
46bed679 L |
378 | |
379 | if (list != NULL) | |
380 | { | |
b77db948 | 381 | /* Discard the .note.gnu.property section in this bfd. */ |
46bed679 L |
382 | sec = bfd_get_section_by_name (abfd, |
383 | NOTE_GNU_PROPERTY_SECTION_NAME); | |
b77db948 NC |
384 | if (sec != NULL) |
385 | sec->output_section = bfd_abs_section_ptr; | |
46bed679 L |
386 | } |
387 | } | |
388 | ||
389 | /* Rewrite .note.gnu.property section so that GNU properties are | |
390 | always sorted by type even if input GNU properties aren't sorted. */ | |
391 | if (first_pbfd != NULL) | |
392 | { | |
393 | unsigned int size; | |
394 | unsigned int descsz; | |
395 | bfd_byte *contents; | |
396 | Elf_External_Note *e_note; | |
397 | unsigned int align_size = bed->s->elfclass == ELFCLASS64 ? 8 : 4; | |
398 | ||
399 | sec = bfd_get_section_by_name (first_pbfd, | |
400 | NOTE_GNU_PROPERTY_SECTION_NAME); | |
b77db948 | 401 | BFD_ASSERT (sec != NULL); |
46bed679 L |
402 | |
403 | /* Update stack size in .note.gnu.property with -z stack-size=N | |
404 | if N > 0. */ | |
405 | if (info->stacksize > 0) | |
406 | { | |
407 | elf_property *p; | |
408 | bfd_vma stacksize = info->stacksize; | |
409 | ||
410 | p = _bfd_elf_get_property (first_pbfd, GNU_PROPERTY_STACK_SIZE, | |
411 | align_size); | |
412 | if (p->pr_kind == property_unknown) | |
413 | { | |
414 | /* Create GNU_PROPERTY_STACK_SIZE. */ | |
415 | p->u.number = stacksize; | |
416 | p->pr_kind = property_number; | |
417 | } | |
418 | else if (stacksize > p->u.number) | |
419 | p->u.number = stacksize; | |
420 | } | |
421 | else if (elf_properties (first_pbfd) == NULL) | |
422 | { | |
423 | /* Discard .note.gnu.property section if all properties have | |
424 | been removed. */ | |
425 | sec->output_section = bfd_abs_section_ptr; | |
fba37edd | 426 | return NULL; |
46bed679 L |
427 | } |
428 | ||
429 | /* Compute the section size. */ | |
430 | descsz = offsetof (Elf_External_Note, name[sizeof "GNU"]); | |
431 | descsz = (descsz + 3) & -(unsigned int) 4; | |
432 | size = descsz; | |
433 | for (list = elf_properties (first_pbfd); | |
434 | list != NULL; | |
435 | list = list->next) | |
436 | { | |
437 | /* There are 4 byte type + 4 byte datasz for each property. */ | |
438 | size += 4 + 4 + list->property.pr_datasz; | |
439 | /* Align each property. */ | |
440 | size = (size + (align_size - 1)) & ~(align_size - 1); | |
441 | } | |
442 | ||
443 | /* Update .note.gnu.property section now. */ | |
444 | sec->size = size; | |
445 | contents = (bfd_byte *) bfd_zalloc (first_pbfd, size); | |
446 | ||
447 | e_note = (Elf_External_Note *) contents; | |
448 | bfd_h_put_32 (first_pbfd, sizeof "GNU", &e_note->namesz); | |
449 | bfd_h_put_32 (first_pbfd, size - descsz, &e_note->descsz); | |
450 | bfd_h_put_32 (first_pbfd, NT_GNU_PROPERTY_TYPE_0, &e_note->type); | |
451 | memcpy (e_note->name, "GNU", sizeof "GNU"); | |
452 | ||
453 | size = descsz; | |
454 | for (list = elf_properties (first_pbfd); | |
455 | list != NULL; | |
456 | list = list->next) | |
457 | { | |
458 | /* There are 4 byte type + 4 byte datasz for each property. */ | |
459 | bfd_h_put_32 (first_pbfd, list->property.pr_type, | |
460 | contents + size); | |
461 | bfd_h_put_32 (first_pbfd, list->property.pr_datasz, | |
462 | contents + size + 4); | |
463 | size += 4 + 4; | |
464 | ||
465 | /* Write out property value. */ | |
466 | switch (list->property.pr_kind) | |
467 | { | |
468 | case property_number: | |
469 | switch (list->property.pr_datasz) | |
470 | { | |
471 | default: | |
472 | /* Never should happen. */ | |
473 | abort (); | |
474 | ||
475 | case 0: | |
476 | break; | |
477 | ||
478 | case 4: | |
479 | bfd_h_put_32 (first_pbfd, list->property.u.number, | |
480 | contents + size); | |
481 | break; | |
482 | ||
483 | case 8: | |
484 | bfd_h_put_64 (first_pbfd, list->property.u.number, | |
485 | contents + size); | |
486 | break; | |
487 | } | |
488 | break; | |
489 | ||
490 | default: | |
491 | /* Never should happen. */ | |
492 | abort (); | |
493 | } | |
494 | size += list->property.pr_datasz; | |
495 | ||
496 | /* Align each property. */ | |
497 | size = (size + (align_size - 1)) & ~ (align_size - 1); | |
498 | } | |
499 | ||
500 | /* Cache the section contents for elf_link_input_bfd. */ | |
501 | elf_section_data (sec)->this_hdr.contents = contents; | |
a5b4ee94 L |
502 | |
503 | /* If GNU_PROPERTY_NO_COPY_ON_PROTECTED is set, protected data | |
504 | symbol is defined in the shared object. */ | |
505 | if (elf_has_no_copy_on_protected (first_pbfd)) | |
506 | info->extern_protected_data = FALSE; | |
46bed679 | 507 | } |
fba37edd L |
508 | |
509 | return first_pbfd; | |
46bed679 | 510 | } |