Line data Source code
1 : /* Sniff out modules from ELF headers visible in memory segments.
2 : Copyright (C) 2008-2012, 2014, 2015, 2018 Red Hat, Inc.
3 : This file is part of elfutils.
4 :
5 : This file is free software; you can redistribute it and/or modify
6 : it under the terms of either
7 :
8 : * the GNU Lesser General Public License as published by the Free
9 : Software Foundation; either version 3 of the License, or (at
10 : your option) any later version
11 :
12 : or
13 :
14 : * the GNU General Public License as published by the Free
15 : Software Foundation; either version 2 of the License, or (at
16 : your option) any later version
17 :
18 : or both in parallel, as here.
19 :
20 : elfutils is distributed in the hope that it will be useful, but
21 : WITHOUT ANY WARRANTY; without even the implied warranty of
22 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 : General Public License for more details.
24 :
25 : You should have received copies of the GNU General Public License and
26 : the GNU Lesser General Public License along with this program. If
27 : not, see <http://www.gnu.org/licenses/>. */
28 :
29 : #include <config.h>
30 : #include "../libelf/libelfP.h" /* For NOTE_ALIGN4 and NOTE_ALIGN8. */
31 : #undef _
32 : #include "libdwflP.h"
33 : #include "common.h"
34 :
35 : #include <elf.h>
36 : #include <gelf.h>
37 : #include <inttypes.h>
38 : #include <endian.h>
39 : #include <unistd.h>
40 : #include <fcntl.h>
41 :
42 : #include <system.h>
43 :
44 :
45 : /* A good size for the initial read from memory, if it's not too costly.
46 : This more than covers the phdrs and note segment in the average 64-bit
47 : binary. */
48 :
49 : #define INITIAL_READ 1024
50 :
51 : #if __BYTE_ORDER == __LITTLE_ENDIAN
52 : # define MY_ELFDATA ELFDATA2LSB
53 : #else
54 : # define MY_ELFDATA ELFDATA2MSB
55 : #endif
56 :
57 :
58 : /* Return user segment index closest to ADDR but not above it.
59 : If NEXT, return the closest to ADDR but not below it. */
60 : static int
61 192 : addr_segndx (Dwfl *dwfl, size_t segment, GElf_Addr addr, bool next)
62 : {
63 192 : int ndx = -1;
64 : do
65 : {
66 595 : if (dwfl->lookup_segndx[segment] >= 0)
67 557 : ndx = dwfl->lookup_segndx[segment];
68 595 : if (++segment >= dwfl->lookup_elts - 1)
69 2 : return next ? ndx + 1 : ndx;
70 : }
71 593 : while (dwfl->lookup_addr[segment] < addr);
72 :
73 190 : if (next)
74 : {
75 219 : while (dwfl->lookup_segndx[segment] < 0)
76 103 : if (++segment >= dwfl->lookup_elts - 1)
77 0 : return ndx + 1;
78 : ndx = dwfl->lookup_segndx[segment];
79 : }
80 :
81 : return ndx;
82 : }
83 :
84 : /* Return whether there is SZ bytes available at PTR till END. */
85 :
86 : static bool
87 : buf_has_data (const void *ptr, const void *end, size_t sz)
88 : {
89 3752 : return ptr < end && (size_t) (end - ptr) >= sz;
90 : }
91 :
92 : /* Read SZ bytes into *RETP from *PTRP (limited by END) in format EI_DATA.
93 : Function comes from src/readelf.c . */
94 :
95 : static bool
96 3661 : buf_read_ulong (unsigned char ei_data, size_t sz,
97 : const void **ptrp, const void *end, uint64_t *retp)
98 : {
99 7504 : if (! buf_has_data (*ptrp, end, sz))
100 : return false;
101 :
102 : union
103 : {
104 : uint64_t u64;
105 : uint32_t u32;
106 : } u;
107 :
108 7504 : memcpy (&u, *ptrp, sz);
109 3752 : (*ptrp) += sz;
110 :
111 3661 : if (retp == NULL)
112 : return true;
113 :
114 3661 : if (MY_ELFDATA != ei_data)
115 : {
116 11 : if (sz == 4)
117 22 : CONVERT (u.u32);
118 : else
119 0 : CONVERT (u.u64);
120 : }
121 3661 : if (sz == 4)
122 91 : *retp = u.u32;
123 : else
124 3570 : *retp = u.u64;
125 : return true;
126 : }
127 :
128 : /* Try to find matching entry for module from address MODULE_START to
129 : MODULE_END in NT_FILE note located at NOTE_FILE of NOTE_FILE_SIZE
130 : bytes in format EI_CLASS and EI_DATA. */
131 :
132 : static const char *
133 118 : handle_file_note (GElf_Addr module_start, GElf_Addr module_end,
134 : unsigned char ei_class, unsigned char ei_data,
135 : const void *note_file, size_t note_file_size)
136 : {
137 118 : if (note_file == NULL)
138 : return NULL;
139 :
140 : size_t sz;
141 91 : switch (ei_class)
142 : {
143 : case ELFCLASS32:
144 : sz = 4;
145 : break;
146 84 : case ELFCLASS64:
147 84 : sz = 8;
148 84 : break;
149 : default:
150 : return NULL;
151 : }
152 :
153 91 : const void *ptr = note_file;
154 91 : const void *end = note_file + note_file_size;
155 : uint64_t count;
156 91 : if (! buf_read_ulong (ei_data, sz, &ptr, end, &count))
157 : return NULL;
158 91 : if (! buf_read_ulong (ei_data, sz, &ptr, end, NULL)) // page_size
159 : return NULL;
160 :
161 91 : uint64_t maxcount = (size_t) (end - ptr) / (3 * sz);
162 91 : if (count > maxcount)
163 : return NULL;
164 :
165 : /* Where file names are stored. */
166 91 : const char *fptr = ptr + 3 * count * sz;
167 :
168 91 : ssize_t firstix = -1;
169 91 : ssize_t lastix = -1;
170 1229 : for (size_t mix = 0; mix < count; mix++)
171 : {
172 : uint64_t mstart, mend, moffset;
173 1190 : if (! buf_read_ulong (ei_data, sz, &ptr, fptr, &mstart)
174 1190 : || ! buf_read_ulong (ei_data, sz, &ptr, fptr, &mend)
175 1190 : || ! buf_read_ulong (ei_data, sz, &ptr, fptr, &moffset))
176 0 : return NULL;
177 1190 : if (mstart == module_start && moffset == 0)
178 67 : firstix = lastix = mix;
179 1190 : if (firstix != -1 && mstart < module_end)
180 240 : lastix = mix;
181 1190 : if (mend >= module_end)
182 : break;
183 : }
184 91 : if (firstix == -1)
185 : return NULL;
186 :
187 : const char *retval = NULL;
188 830 : for (ssize_t mix = 0; mix <= lastix; mix++)
189 : {
190 830 : const char *fnext = memchr (fptr, 0, (const char *) end - fptr);
191 830 : if (fnext == NULL)
192 : return NULL;
193 830 : if (mix == firstix)
194 67 : retval = fptr;
195 830 : if (firstix < mix && mix <= lastix && strcmp (fptr, retval) != 0)
196 : return NULL;
197 830 : fptr = fnext + 1;
198 : }
199 : return retval;
200 : }
201 :
202 : /* Return true iff we are certain ELF cannot match BUILD_ID of
203 : BUILD_ID_LEN bytes. Pass DISK_FILE_HAS_BUILD_ID as false if it is
204 : certain ELF does not contain build-id (it is only a performance hit
205 : to pass it always as true). */
206 :
207 : static bool
208 67 : invalid_elf (Elf *elf, bool disk_file_has_build_id,
209 : const void *build_id, size_t build_id_len)
210 : {
211 67 : if (! disk_file_has_build_id && build_id_len > 0)
212 : {
213 : /* Module found in segments with build-id is more reliable
214 : than a module found via DT_DEBUG on disk without any
215 : build-id. */
216 : return true;
217 : }
218 67 : if (disk_file_has_build_id && build_id_len > 0)
219 : {
220 : const void *elf_build_id;
221 : ssize_t elf_build_id_len;
222 :
223 : /* If there is a build id in the elf file, check it. */
224 66 : elf_build_id_len = INTUSE(dwelf_elf_gnu_build_id) (elf, &elf_build_id);
225 66 : if (elf_build_id_len > 0)
226 : {
227 66 : if (build_id_len != (size_t) elf_build_id_len
228 66 : || memcmp (build_id, elf_build_id, build_id_len) != 0)
229 12 : return true;
230 : }
231 : }
232 : return false;
233 : }
234 :
235 : int
236 459 : dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name,
237 : Dwfl_Memory_Callback *memory_callback,
238 : void *memory_callback_arg,
239 : Dwfl_Module_Callback *read_eagerly,
240 : void *read_eagerly_arg,
241 : const void *note_file, size_t note_file_size,
242 : const struct r_debug_info *r_debug_info)
243 : {
244 459 : size_t segment = ndx;
245 :
246 459 : if (segment >= dwfl->lookup_elts)
247 0 : segment = dwfl->lookup_elts - 1;
248 :
249 598 : while (segment > 0
250 542 : && (dwfl->lookup_segndx[segment] > ndx
251 523 : || dwfl->lookup_segndx[segment] == -1))
252 139 : --segment;
253 :
254 1986 : while (dwfl->lookup_segndx[segment] < ndx)
255 1527 : if (++segment == dwfl->lookup_elts)
256 : return 0;
257 :
258 459 : GElf_Addr start = dwfl->lookup_addr[segment];
259 :
260 : inline bool segment_read (int segndx,
261 : void **buffer, size_t *buffer_available,
262 : GElf_Addr addr, size_t minread)
263 : {
264 986 : return ! (*memory_callback) (dwfl, segndx, buffer, buffer_available,
265 70 : addr, minread, memory_callback_arg);
266 : }
267 :
268 : inline void release_buffer (void **buffer, size_t *buffer_available)
269 : {
270 529 : if (*buffer != NULL)
271 : (void) segment_read (-1, buffer, buffer_available, 0, 0);
272 : }
273 :
274 : /* First read in the file header and check its sanity. */
275 :
276 459 : void *buffer = NULL;
277 459 : size_t buffer_available = INITIAL_READ;
278 459 : Elf *elf = NULL;
279 459 : int fd = -1;
280 :
281 : /* We might have to reserve some memory for the phdrs. Set to NULL
282 : here so we can always safely free it. */
283 459 : void *phdrsp = NULL;
284 :
285 459 : inline int finish (void)
286 : {
287 459 : free (phdrsp);
288 918 : release_buffer (&buffer, &buffer_available);
289 459 : if (elf != NULL)
290 0 : elf_end (elf);
291 459 : if (fd != -1)
292 0 : close (fd);
293 459 : return ndx;
294 : }
295 :
296 918 : if (segment_read (ndx, &buffer, &buffer_available,
297 : start, sizeof (Elf64_Ehdr))
298 419 : || memcmp (buffer, ELFMAG, SELFMAG) != 0)
299 287 : return finish ();
300 :
301 478 : inline bool read_portion (void **data, size_t *data_size,
302 : GElf_Addr vaddr, size_t filesz)
303 : {
304 : /* Check whether we will have to read the segment data, or if it
305 : can be returned from the existing buffer. */
306 478 : if (filesz > buffer_available
307 478 : || vaddr - start > buffer_available - filesz
308 : /* If we're in string mode, then don't consider the buffer we have
309 : sufficient unless it contains the terminator of the string. */
310 439 : || (filesz == 0 && memchr (vaddr - start + buffer, '\0',
311 31 : buffer_available - (vaddr - start)) == NULL))
312 : {
313 70 : *data = NULL;
314 70 : *data_size = filesz;
315 140 : return segment_read (addr_segndx (dwfl, segment, vaddr, false),
316 : data, data_size, vaddr, filesz);
317 : }
318 :
319 : /* We already have this whole note segment from our initial read. */
320 408 : *data = vaddr - start + buffer;
321 408 : *data_size = 0;
322 408 : return false;
323 : }
324 :
325 : inline void finish_portion (void **data, size_t *data_size)
326 : {
327 578 : if (*data_size != 0)
328 : release_buffer (data, data_size);
329 : }
330 :
331 : /* Extract the information we need from the file header. */
332 : const unsigned char *e_ident;
333 : unsigned char ei_class;
334 : unsigned char ei_data;
335 : uint16_t e_type;
336 : union
337 : {
338 : Elf32_Ehdr e32;
339 : Elf64_Ehdr e64;
340 : } ehdr;
341 : GElf_Off phoff;
342 : uint_fast16_t phnum;
343 : uint_fast16_t phentsize;
344 : GElf_Off shdrs_end;
345 172 : Elf_Data xlatefrom =
346 : {
347 : .d_type = ELF_T_EHDR,
348 : .d_buf = (void *) buffer,
349 : .d_version = EV_CURRENT,
350 : };
351 172 : Elf_Data xlateto =
352 : {
353 : .d_type = ELF_T_EHDR,
354 : .d_buf = &ehdr,
355 : .d_size = sizeof ehdr,
356 : .d_version = EV_CURRENT,
357 : };
358 172 : e_ident = ((const unsigned char *) buffer);
359 172 : ei_class = e_ident[EI_CLASS];
360 172 : ei_data = e_ident[EI_DATA];
361 172 : switch (ei_class)
362 : {
363 27 : case ELFCLASS32:
364 27 : xlatefrom.d_size = sizeof (Elf32_Ehdr);
365 27 : if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
366 0 : return finish ();
367 27 : e_type = ehdr.e32.e_type;
368 27 : phoff = ehdr.e32.e_phoff;
369 27 : phnum = ehdr.e32.e_phnum;
370 27 : phentsize = ehdr.e32.e_phentsize;
371 27 : if (phentsize != sizeof (Elf32_Phdr))
372 0 : return finish ();
373 : /* NOTE if the number of sections is > 0xff00 then e_shnum
374 : is zero and the actual number would come from the section
375 : zero sh_size field. We ignore this here because getting shdrs
376 : is just a nice bonus (see below in consider_phdr PT_LOAD
377 : where we trim the last segment). */
378 27 : shdrs_end = ehdr.e32.e_shoff + ehdr.e32.e_shnum * ehdr.e32.e_shentsize;
379 27 : break;
380 :
381 145 : case ELFCLASS64:
382 145 : xlatefrom.d_size = sizeof (Elf64_Ehdr);
383 145 : if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
384 0 : return finish ();
385 145 : e_type = ehdr.e64.e_type;
386 145 : phoff = ehdr.e64.e_phoff;
387 145 : phnum = ehdr.e64.e_phnum;
388 145 : phentsize = ehdr.e64.e_phentsize;
389 145 : if (phentsize != sizeof (Elf64_Phdr))
390 0 : return finish ();
391 : /* See the NOTE above for shdrs_end and ehdr.e32.e_shnum. */
392 145 : shdrs_end = ehdr.e64.e_shoff + ehdr.e64.e_shnum * ehdr.e64.e_shentsize;
393 145 : break;
394 :
395 0 : default:
396 0 : return finish ();
397 : }
398 :
399 : /* The file header tells where to find the program headers.
400 : These are what we need to find the boundaries of the module.
401 : Without them, we don't have a module to report. */
402 :
403 172 : if (phnum == 0)
404 0 : return finish ();
405 :
406 172 : xlatefrom.d_type = xlateto.d_type = ELF_T_PHDR;
407 172 : xlatefrom.d_size = phnum * phentsize;
408 :
409 172 : void *ph_buffer = NULL;
410 172 : size_t ph_buffer_size = 0;
411 172 : if (read_portion (&ph_buffer, &ph_buffer_size,
412 : start + phoff, xlatefrom.d_size))
413 0 : return finish ();
414 :
415 172 : xlatefrom.d_buf = ph_buffer;
416 :
417 172 : bool class32 = ei_class == ELFCLASS32;
418 172 : size_t phdr_size = class32 ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr);
419 172 : if (unlikely (phnum > SIZE_MAX / phdr_size))
420 0 : return finish ();
421 172 : const size_t phdrsp_bytes = phnum * phdr_size;
422 172 : phdrsp = malloc (phdrsp_bytes);
423 172 : if (unlikely (phdrsp == NULL))
424 0 : return finish ();
425 :
426 172 : xlateto.d_buf = phdrsp;
427 172 : xlateto.d_size = phdrsp_bytes;
428 :
429 : /* Track the bounds of the file visible in memory. */
430 172 : GElf_Off file_trimmed_end = 0; /* Proper p_vaddr + p_filesz end. */
431 172 : GElf_Off file_end = 0; /* Rounded up to effective page size. */
432 172 : GElf_Off contiguous = 0; /* Visible as contiguous file from START. */
433 172 : GElf_Off total_filesz = 0; /* Total size of data to read. */
434 :
435 : /* Collect the bias between START and the containing PT_LOAD's p_vaddr. */
436 172 : GElf_Addr bias = 0;
437 172 : bool found_bias = false;
438 :
439 : /* Collect the unbiased bounds of the module here. */
440 172 : GElf_Addr module_start = -1l;
441 172 : GElf_Addr module_end = 0;
442 172 : GElf_Addr module_address_sync = 0;
443 :
444 : /* If we see PT_DYNAMIC, record it here. */
445 172 : GElf_Addr dyn_vaddr = 0;
446 172 : GElf_Xword dyn_filesz = 0;
447 :
448 : /* Collect the build ID bits here. */
449 172 : void *build_id = NULL;
450 172 : size_t build_id_len = 0;
451 172 : GElf_Addr build_id_vaddr = 0;
452 :
453 : /* Consider a PT_NOTE we've found in the image. */
454 170 : inline void consider_notes (GElf_Addr vaddr, GElf_Xword filesz,
455 : GElf_Xword align)
456 : {
457 : /* If we have already seen a build ID, we don't care any more. */
458 170 : if (build_id != NULL || filesz == 0)
459 0 : return;
460 :
461 : void *data;
462 : size_t data_size;
463 170 : if (read_portion (&data, &data_size, vaddr, filesz))
464 : return;
465 :
466 : /* data_size will be zero if we got everything from the initial
467 : buffer, otherwise it will be the size of the new buffer that
468 : could be read. */
469 170 : if (data_size != 0)
470 0 : filesz = data_size;
471 :
472 : assert (sizeof (Elf32_Nhdr) == sizeof (Elf64_Nhdr));
473 :
474 : void *notes;
475 170 : if (ei_data == MY_ELFDATA)
476 148 : notes = data;
477 : else
478 : {
479 22 : notes = malloc (filesz);
480 22 : if (unlikely (notes == NULL))
481 : return;
482 22 : xlatefrom.d_type = xlateto.d_type = (align == 8
483 22 : ? ELF_T_NHDR8 : ELF_T_NHDR);
484 22 : xlatefrom.d_buf = (void *) data;
485 22 : xlatefrom.d_size = filesz;
486 22 : xlateto.d_buf = notes;
487 22 : xlateto.d_size = filesz;
488 22 : if (elf32_xlatetom (&xlateto, &xlatefrom,
489 22 : ehdr.e32.e_ident[EI_DATA]) == NULL)
490 : goto done;
491 : }
492 :
493 170 : const GElf_Nhdr *nh = notes;
494 170 : size_t len = 0;
495 424 : while (filesz > len + sizeof (*nh))
496 : {
497 : const void *note_name;
498 : const void *note_desc;
499 :
500 254 : len += sizeof (*nh);
501 254 : note_name = notes + len;
502 :
503 254 : len += nh->n_namesz;
504 254 : len = align == 8 ? NOTE_ALIGN8 (len) : NOTE_ALIGN4 (len);
505 254 : note_desc = notes + len;
506 :
507 254 : if (unlikely (filesz < len + nh->n_descsz))
508 : break;
509 :
510 254 : if (nh->n_type == NT_GNU_BUILD_ID
511 170 : && nh->n_descsz > 0
512 170 : && nh->n_namesz == sizeof "GNU"
513 170 : && !memcmp (note_name, "GNU", sizeof "GNU"))
514 : {
515 170 : build_id_vaddr = note_desc - (const void *) notes + vaddr;
516 170 : build_id_len = nh->n_descsz;
517 170 : build_id = malloc (nh->n_descsz);
518 170 : if (likely (build_id != NULL))
519 170 : memcpy (build_id, note_desc, build_id_len);
520 : break;
521 : }
522 :
523 84 : len += nh->n_descsz;
524 84 : len = align == 8 ? NOTE_ALIGN8 (len) : NOTE_ALIGN4 (len);
525 84 : nh = (void *) notes + len;
526 : }
527 :
528 0 : done:
529 170 : if (notes != data)
530 22 : free (notes);
531 170 : finish_portion (&data, &data_size);
532 : }
533 :
534 : /* Consider each of the program headers we've read from the image. */
535 1274 : inline void consider_phdr (GElf_Word type,
536 : GElf_Addr vaddr, GElf_Xword memsz,
537 : GElf_Off offset, GElf_Xword filesz,
538 : GElf_Xword align)
539 : {
540 1274 : switch (type)
541 : {
542 159 : case PT_DYNAMIC:
543 159 : dyn_vaddr = vaddr;
544 159 : dyn_filesz = filesz;
545 159 : break;
546 :
547 170 : case PT_NOTE:
548 : /* We calculate from the p_offset of the note segment,
549 : because we don't yet know the bias for its p_vaddr. */
550 170 : consider_notes (start + offset, filesz, align);
551 170 : break;
552 :
553 332 : case PT_LOAD:
554 332 : align = dwfl->segment_align > 1 ? dwfl->segment_align : align ?: 1;
555 :
556 332 : GElf_Addr vaddr_end = (vaddr + memsz + align - 1) & -align;
557 332 : GElf_Addr filesz_vaddr = filesz < memsz ? vaddr + filesz : vaddr_end;
558 332 : GElf_Off filesz_offset = filesz_vaddr - vaddr + offset;
559 :
560 332 : if (file_trimmed_end < offset + filesz)
561 : {
562 324 : file_trimmed_end = offset + filesz;
563 :
564 : /* Trim the last segment so we don't bother with zeros
565 : in the last page that are off the end of the file.
566 : However, if the extra bit in that page includes the
567 : section headers, keep them. */
568 324 : if (shdrs_end <= filesz_offset && shdrs_end > file_trimmed_end)
569 : {
570 24 : filesz += shdrs_end - file_trimmed_end;
571 24 : file_trimmed_end = shdrs_end;
572 : }
573 : }
574 :
575 332 : total_filesz += filesz;
576 :
577 332 : if (file_end < filesz_offset)
578 : {
579 318 : file_end = filesz_offset;
580 318 : if (filesz_vaddr - start == filesz_offset)
581 115 : contiguous = file_end;
582 : }
583 :
584 332 : if (!found_bias && (offset & -align) == 0
585 172 : && likely (filesz_offset >= phoff + phnum * phentsize))
586 : {
587 172 : bias = start - vaddr;
588 172 : found_bias = true;
589 : }
590 :
591 332 : if ((vaddr & -align) < module_start)
592 : {
593 172 : module_start = vaddr & -align;
594 172 : module_address_sync = vaddr + memsz;
595 : }
596 :
597 332 : if (module_end < vaddr_end)
598 332 : module_end = vaddr_end;
599 : break;
600 : }
601 1274 : }
602 :
603 172 : Elf32_Phdr (*p32)[phnum] = phdrsp;
604 172 : Elf64_Phdr (*p64)[phnum] = phdrsp;
605 172 : if (ei_class == ELFCLASS32)
606 : {
607 27 : if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
608 0 : found_bias = false; /* Trigger error check. */
609 : else
610 195 : for (uint_fast16_t i = 0; i < phnum; ++i)
611 975 : consider_phdr ((*p32)[i].p_type,
612 390 : (*p32)[i].p_vaddr, (*p32)[i].p_memsz,
613 390 : (*p32)[i].p_offset, (*p32)[i].p_filesz,
614 195 : (*p32)[i].p_align);
615 : }
616 : else
617 : {
618 145 : if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) == NULL)
619 0 : found_bias = false; /* Trigger error check. */
620 : else
621 1079 : for (uint_fast16_t i = 0; i < phnum; ++i)
622 1079 : consider_phdr ((*p64)[i].p_type,
623 : (*p64)[i].p_vaddr, (*p64)[i].p_memsz,
624 : (*p64)[i].p_offset, (*p64)[i].p_filesz,
625 : (*p64)[i].p_align);
626 : }
627 :
628 172 : finish_portion (&ph_buffer, &ph_buffer_size);
629 :
630 : /* We must have seen the segment covering offset 0, or else the ELF
631 : header we read at START was not produced by these program headers. */
632 172 : if (unlikely (!found_bias))
633 : {
634 0 : free (build_id);
635 0 : return finish ();
636 : }
637 :
638 : /* Now we know enough to report a module for sure: its bounds. */
639 172 : module_start += bias;
640 172 : module_end += bias;
641 :
642 172 : dyn_vaddr += bias;
643 :
644 : /* NAME found from link map has precedence over DT_SONAME possibly read
645 : below. */
646 172 : bool name_is_final = false;
647 :
648 : /* Try to match up DYN_VADDR against L_LD as found in link map.
649 : Segments sniffing may guess invalid address as the first read-only memory
650 : mapping may not be dumped to the core file (if ELF headers are not dumped)
651 : and the ELF header is dumped first with the read/write mapping of the same
652 : file at higher addresses. */
653 172 : if (r_debug_info != NULL)
654 796 : for (const struct r_debug_info_module *module = r_debug_info->module;
655 452 : module != NULL; module = module->next)
656 593 : if (module_start <= module->l_ld && module->l_ld < module_end)
657 : {
658 : /* L_LD read from link map must be right while DYN_VADDR is unsafe.
659 : Therefore subtract DYN_VADDR and add L_LD to get a possibly
660 : corrective displacement for all addresses computed so far. */
661 141 : GElf_Addr fixup = module->l_ld - dyn_vaddr;
662 141 : if ((fixup & (dwfl->segment_align - 1)) == 0
663 141 : && module_start + fixup <= module->l_ld
664 141 : && module->l_ld < module_end + fixup)
665 : {
666 141 : module_start += fixup;
667 141 : module_end += fixup;
668 141 : dyn_vaddr += fixup;
669 141 : bias += fixup;
670 141 : if (module->name[0] != '\0')
671 : {
672 120 : name = basename (module->name);
673 120 : name_is_final = true;
674 : }
675 : break;
676 : }
677 : }
678 :
679 172 : if (r_debug_info != NULL)
680 : {
681 172 : bool skip_this_module = false;
682 1229 : for (struct r_debug_info_module *module = r_debug_info->module;
683 885 : module != NULL; module = module->next)
684 885 : if ((module_end > module->start && module_start < module->end)
685 818 : || dyn_vaddr == module->l_ld)
686 : {
687 142 : if (module->elf != NULL
688 66 : && invalid_elf (module->elf, module->disk_file_has_build_id,
689 : build_id, build_id_len))
690 : {
691 12 : elf_end (module->elf);
692 12 : close (module->fd);
693 12 : module->elf = NULL;
694 12 : module->fd = -1;
695 : }
696 142 : if (module->elf != NULL)
697 : {
698 : /* Ignore this found module if it would conflict in address
699 : space with any already existing module of DWFL. */
700 54 : skip_this_module = true;
701 : }
702 : }
703 172 : if (skip_this_module)
704 : {
705 54 : free (build_id);
706 54 : return finish ();
707 : }
708 : }
709 :
710 118 : const char *file_note_name = handle_file_note (module_start, module_end,
711 : ei_class, ei_data,
712 : note_file, note_file_size);
713 118 : if (file_note_name)
714 : {
715 67 : name = file_note_name;
716 67 : name_is_final = true;
717 67 : bool invalid = false;
718 67 : fd = open (name, O_RDONLY);
719 67 : if (fd >= 0)
720 : {
721 1 : Dwfl_Error error = __libdw_open_file (&fd, &elf, true, false);
722 1 : if (error == DWFL_E_NOERROR)
723 1 : invalid = invalid_elf (elf, true /* disk_file_has_build_id */,
724 : build_id, build_id_len);
725 : }
726 1 : if (invalid)
727 : {
728 : /* The file was there, but the build_id didn't match. We
729 : still want to report the module, but need to get the ELF
730 : some other way if possible. */
731 0 : close (fd);
732 0 : fd = -1;
733 0 : elf_end (elf);
734 0 : elf = NULL;
735 : }
736 : }
737 :
738 : /* Our return value now says to skip the segments contained
739 : within the module. */
740 118 : ndx = addr_segndx (dwfl, segment, module_end, true);
741 :
742 : /* Examine its .dynamic section to get more interesting details.
743 : If it has DT_SONAME, we'll use that as the module name.
744 : If it has a DT_DEBUG, then it's actually a PIE rather than a DSO.
745 : We need its DT_STRTAB and DT_STRSZ to decipher DT_SONAME,
746 : and they also tell us the essential portion of the file
747 : for fetching symbols. */
748 118 : GElf_Addr soname_stroff = 0;
749 118 : GElf_Addr dynstr_vaddr = 0;
750 118 : GElf_Xword dynstrsz = 0;
751 118 : bool execlike = false;
752 1089 : inline bool consider_dyn (GElf_Sxword tag, GElf_Xword val)
753 : {
754 1089 : switch (tag)
755 : {
756 : default:
757 : return false;
758 :
759 5 : case DT_DEBUG:
760 5 : execlike = true;
761 5 : break;
762 :
763 98 : case DT_SONAME:
764 98 : soname_stroff = val;
765 98 : break;
766 :
767 105 : case DT_STRTAB:
768 105 : dynstr_vaddr = val;
769 105 : break;
770 :
771 105 : case DT_STRSZ:
772 105 : dynstrsz = val;
773 105 : break;
774 : }
775 :
776 313 : return soname_stroff != 0 && dynstr_vaddr != 0 && dynstrsz != 0;
777 : }
778 :
779 118 : const size_t dyn_entsize = (ei_class == ELFCLASS32
780 118 : ? sizeof (Elf32_Dyn) : sizeof (Elf64_Dyn));
781 118 : void *dyn_data = NULL;
782 118 : size_t dyn_data_size = 0;
783 118 : if (dyn_filesz != 0 && dyn_filesz % dyn_entsize == 0
784 105 : && ! read_portion (&dyn_data, &dyn_data_size, dyn_vaddr, dyn_filesz))
785 : {
786 105 : void *dyns = malloc (dyn_filesz);
787 105 : Elf32_Dyn (*d32)[dyn_filesz / sizeof (Elf32_Dyn)] = dyns;
788 105 : Elf64_Dyn (*d64)[dyn_filesz / sizeof (Elf64_Dyn)] = dyns;
789 105 : if (unlikely (dyns == NULL))
790 0 : return finish ();
791 :
792 105 : xlatefrom.d_type = xlateto.d_type = ELF_T_DYN;
793 105 : xlatefrom.d_buf = (void *) dyn_data;
794 105 : xlatefrom.d_size = dyn_filesz;
795 105 : xlateto.d_buf = dyns;
796 105 : xlateto.d_size = dyn_filesz;
797 :
798 105 : if (ei_class == ELFCLASS32)
799 : {
800 17 : if (elf32_xlatetom (&xlateto, &xlatefrom, ei_data) != NULL)
801 174 : for (size_t i = 0; i < dyn_filesz / sizeof (Elf32_Dyn); ++i)
802 189 : if (consider_dyn ((*d32)[i].d_tag, (*d32)[i].d_un.d_val))
803 : break;
804 : }
805 : else
806 : {
807 88 : if (elf64_xlatetom (&xlateto, &xlatefrom, ei_data) != NULL)
808 817 : for (size_t i = 0; i < dyn_filesz / sizeof (Elf64_Dyn); ++i)
809 900 : if (consider_dyn ((*d64)[i].d_tag, (*d64)[i].d_un.d_val))
810 : break;
811 : }
812 105 : free (dyns);
813 : }
814 118 : finish_portion (&dyn_data, &dyn_data_size);
815 :
816 : /* We'll use the name passed in or a stupid default if not DT_SONAME. */
817 118 : if (name == NULL)
818 41 : name = e_type == ET_EXEC ? "[exe]" : execlike ? "[pie]" : "[dso]";
819 :
820 118 : void *soname = NULL;
821 118 : size_t soname_size = 0;
822 118 : if (! name_is_final && dynstrsz != 0 && dynstr_vaddr != 0)
823 : {
824 : /* We know the bounds of the .dynstr section.
825 :
826 : The DYNSTR_VADDR pointer comes from the .dynamic section
827 : (DT_STRTAB, detected above). Ordinarily the dynamic linker
828 : will have adjusted this pointer in place so it's now an
829 : absolute address. But sometimes .dynamic is read-only (in
830 : vDSOs and odd architectures), and sometimes the adjustment
831 : just hasn't happened yet in the memory image we looked at.
832 : So treat DYNSTR_VADDR as an absolute address if it falls
833 : within the module bounds, or try applying the phdr bias
834 : when that adjusts it to fall within the module bounds. */
835 :
836 36 : if ((dynstr_vaddr < module_start || dynstr_vaddr >= module_end)
837 28 : && dynstr_vaddr + bias >= module_start
838 28 : && dynstr_vaddr + bias < module_end)
839 28 : dynstr_vaddr += bias;
840 :
841 36 : if (unlikely (dynstr_vaddr + dynstrsz > module_end))
842 0 : dynstrsz = 0;
843 :
844 : /* Try to get the DT_SONAME string. */
845 36 : if (soname_stroff != 0 && soname_stroff + 1 < dynstrsz
846 31 : && ! read_portion (&soname, &soname_size,
847 : dynstr_vaddr + soname_stroff, 0))
848 31 : name = soname;
849 : }
850 :
851 : /* Now that we have chosen the module's name and bounds, report it.
852 : If we found a build ID, report that too. */
853 :
854 118 : Dwfl_Module *mod = INTUSE(dwfl_report_module) (dwfl, name,
855 : module_start, module_end);
856 :
857 : // !execlike && ET_EXEC is PIE.
858 : // execlike && !ET_EXEC is a static executable.
859 118 : if (mod != NULL && (execlike || ehdr.e32.e_type == ET_EXEC))
860 18 : mod->is_executable = true;
861 :
862 118 : if (likely (mod != NULL) && build_id != NULL
863 117 : && unlikely (INTUSE(dwfl_module_report_build_id) (mod,
864 : build_id,
865 : build_id_len,
866 : build_id_vaddr)))
867 : {
868 0 : mod->gc = true;
869 0 : mod = NULL;
870 : }
871 :
872 : /* At this point we do not need BUILD_ID or NAME any more.
873 : They have been copied. */
874 118 : free (build_id);
875 118 : finish_portion (&soname, &soname_size);
876 :
877 118 : if (unlikely (mod == NULL))
878 : {
879 0 : ndx = -1;
880 0 : return finish ();
881 : }
882 :
883 : /* We have reported the module. Now let the caller decide whether we
884 : should read the whole thing in right now. */
885 :
886 118 : const GElf_Off cost = (contiguous < file_trimmed_end ? total_filesz
887 228 : : buffer_available >= contiguous ? 0
888 8 : : contiguous - buffer_available);
889 223 : const GElf_Off worthwhile = ((dynstr_vaddr == 0 || dynstrsz == 0) ? 0
890 223 : : dynstr_vaddr + dynstrsz - start);
891 118 : const GElf_Off whole = MAX (file_trimmed_end, shdrs_end);
892 :
893 118 : if (elf == NULL
894 117 : && (*read_eagerly) (MODCB_ARGS (mod), &buffer, &buffer_available,
895 : cost, worthwhile, whole, contiguous,
896 : read_eagerly_arg, &elf)
897 39 : && elf == NULL)
898 : {
899 : /* The caller wants to read the whole file in right now, but hasn't
900 : done it for us. Fill in a local image of the virtual file. */
901 :
902 3 : void *contents = calloc (1, file_trimmed_end);
903 3 : if (unlikely (contents == NULL))
904 0 : return finish ();
905 :
906 4 : inline void final_read (size_t offset, GElf_Addr vaddr, size_t size)
907 : {
908 4 : void *into = contents + offset;
909 4 : size_t read_size = size;
910 8 : (void) segment_read (addr_segndx (dwfl, segment, vaddr, false),
911 : &into, &read_size, vaddr, size);
912 4 : }
913 :
914 3 : if (contiguous < file_trimmed_end)
915 : {
916 : /* We can't use the memory image verbatim as the file image.
917 : So we'll be reading into a local image of the virtual file. */
918 :
919 : inline void read_phdr (GElf_Word type, GElf_Addr vaddr,
920 : GElf_Off offset, GElf_Xword filesz)
921 : {
922 16 : if (type == PT_LOAD)
923 4 : final_read (offset, vaddr + bias, filesz);
924 : }
925 :
926 2 : if (ei_class == ELFCLASS32)
927 0 : for (uint_fast16_t i = 0; i < phnum; ++i)
928 0 : read_phdr ((*p32)[i].p_type, (*p32)[i].p_vaddr,
929 0 : (*p32)[i].p_offset, (*p32)[i].p_filesz);
930 : else
931 16 : for (uint_fast16_t i = 0; i < phnum; ++i)
932 32 : read_phdr ((*p64)[i].p_type, (*p64)[i].p_vaddr,
933 : (*p64)[i].p_offset, (*p64)[i].p_filesz);
934 : }
935 : else
936 : {
937 : /* The whole file sits contiguous in memory,
938 : but the caller didn't want to just do it. */
939 :
940 1 : const size_t have = MIN (buffer_available, file_trimmed_end);
941 2 : memcpy (contents, buffer, have);
942 :
943 1 : if (have < file_trimmed_end)
944 0 : final_read (have, start + have, file_trimmed_end - have);
945 : }
946 :
947 3 : elf = elf_memory (contents, file_trimmed_end);
948 3 : if (unlikely (elf == NULL))
949 0 : free (contents);
950 : else
951 3 : elf->flags |= ELF_F_MALLOCED;
952 : }
953 :
954 118 : if (elf != NULL)
955 : {
956 : /* Install the file in the module. */
957 40 : mod->main.elf = elf;
958 40 : elf = NULL;
959 40 : fd = -1;
960 40 : mod->main.vaddr = module_start - bias;
961 40 : mod->main.address_sync = module_address_sync;
962 40 : mod->main_bias = bias;
963 : }
964 :
965 118 : return finish ();
966 : }
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