-
Notifications
You must be signed in to change notification settings - Fork 24
/
scanelf.c
2347 lines (2155 loc) · 67.7 KB
/
scanelf.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
* Copyright 2003-2024 Gentoo Foundation
* Distributed under the terms of the GNU General Public License v2
*
* Copyright 2003-2012 Ned Ludd - <[email protected]>
* Copyright 2004-2024 Mike Frysinger - <[email protected]>
*/
const char argv0[] = "scanelf";
#include "paxinc.h"
#define IS_MODIFIER(c) (c == '%' || c == '#' || c == '+')
/* prototypes */
static int file_matches_list(const char *filename, char **matchlist);
/* variables to control behavior */
static array_t _match_etypes = array_init_decl, *match_etypes = &_match_etypes;
static char scan_ldpath = 0;
static char scan_envpath = 0;
static char scan_symlink = 1;
static char scan_archives = 0;
static char dir_recurse = 0;
static char dir_crossmount = 1;
static char show_pax = 0;
static char show_perms = 0;
static char show_size = 0;
static char show_phdr = 0;
static char show_textrel = 0;
static char show_rpath = 0;
static char show_needed = 0;
static char show_interp = 0;
static char show_bind = 0;
static char show_soname = 0;
static char show_textrels = 0;
static char show_banner = 1;
static char show_endian = 0;
static char show_osabi = 0;
static char show_eabi = 0;
static char be_quiet = 0;
static char be_verbose = 0;
static char be_wewy_wewy_quiet = 0;
static char be_semi_verbose = 0;
static char *find_sym = NULL;
static array_t _find_sym_arr = array_init_decl, *find_sym_arr = &_find_sym_arr;
static array_t _find_sym_regex_arr = array_init_decl, *find_sym_regex_arr = &_find_sym_regex_arr;
static char *find_lib = NULL;
static array_t _find_lib_arr = array_init_decl, *find_lib_arr = &_find_lib_arr;
static char *find_section = NULL;
static array_t _find_section_arr = array_init_decl, *find_section_arr = &_find_section_arr;
static char *out_format = NULL;
static char *search_path = NULL;
static char fix_elf = 0;
static char g_match = 0;
static char use_ldcache = 0;
static char use_ldpath = 0;
static char **qa_textrels = NULL;
static char **qa_execstack = NULL;
static char **qa_wx_load = NULL;
static int match_bits = 0;
static unsigned int match_perms = 0;
static unsigned long setpax = 0UL;
static const char *objdump;
/* Boiler plate wrapper for expanding ELF macros for specific ELF sizes. */
#define _SCANELF_IF_ELF_SIZE(B, x) \
do { \
if (elf->elf_class == ELFCLASS ## B) { \
x(B); \
} \
} while (0)
#define SCANELF_ELF_SIZED(x) \
do { \
_SCANELF_IF_ELF_SIZE(32, x); \
_SCANELF_IF_ELF_SIZE(64, x); \
} while (0)
/* Find the path to a file by name. Note: we do not currently handle the
* empty path element correctly (should behave by searching $PWD). */
static const char *which(const char *fname, const char *envvar)
{
size_t path_len, fname_len;
const char *env_path;
char *path, *p, *ep;
p = getenv(envvar);
if (p)
return p;
env_path = getenv("PATH");
if (!env_path)
return NULL;
/* Create a copy of the $PATH that we can safely modify.
* Make it a little bigger so we can append "/fname".
* We do this twice -- once for a perm copy, and once for
* room at the end of the last element. */
path_len = strlen(env_path);
fname_len = strlen(fname);
path = xmalloc(path_len + (fname_len * 2) + 2 + 2);
memcpy(path, env_path, path_len + 1);
p = path + path_len + 1 + fname_len + 1;
*p = '/';
memcpy(p + 1, fname, fname_len + 1);
/* Repoint fname to the copy in the env string as it has
* the leading slash which we can include in a single memcpy.
* Increase the fname len to include the '/' and '\0'. */
fname = p;
fname_len += 2;
p = path;
while (p) {
ep = strchr(p, ':');
/* Append the /foo path to the current element. */
if (ep)
memcpy(ep, fname, fname_len);
else
memcpy(path + path_len, fname, fname_len);
if (access(p, R_OK) != -1)
return p;
p = ep;
if (ep) {
/* If not the last element, restore the chunk we clobbered. */
size_t offset = ep - path;
size_t restore = min(path_len - offset, fname_len);
memcpy(ep, env_path + offset, restore);
++p;
}
}
free(path);
return NULL;
}
/*
* Return the index into the program header table for the |p_type| segment.
* Useful only when there is one instance of a particular type.
*/
static ssize_t scanelf_file_find_phdr(elfobj *elf, uint32_t p_type)
{
ssize_t ret = -1;
#define FIND_PT_TYPE(B) \
size_t i; \
const Elf##B##_Ehdr *ehdr = EHDR ## B (elf->ehdr); \
const Elf##B##_Phdr *phdr = PHDR ## B (elf->phdr); \
\
for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
if (EGET(phdr[i].p_type) != p_type) \
continue; \
\
if (ret == -1) \
ret = i; \
else \
warnf("ELF has more than one %s segment !?", get_elfptype(p_type)); \
}
if (elf->phdr)
SCANELF_ELF_SIZED(FIND_PT_TYPE);
return ret;
}
static const void *scanelf_file_get_pt_dynamic(elfobj *elf)
{
ssize_t i = scanelf_file_find_phdr(elf, PT_DYNAMIC);
if (i == -1)
return NULL;
#define CHECK_PT_DYNAMIC(B) \
const Elf##B##_Phdr *phdr = &PHDR##B(elf->phdr)[i]; \
Elf##B##_Off offset; \
\
if (EGET(phdr->p_filesz) == 0) \
break; \
offset = EGET(phdr->p_offset); \
if (!VALID_RANGE(elf, offset, sizeof(Elf##B##_Dyn))) \
break; \
return phdr;
SCANELF_ELF_SIZED(CHECK_PT_DYNAMIC);
return NULL;
}
#define scanelf_dt_for_each(B, elf, dyn) \
{ \
const Elf##B##_Phdr *_phdr = scanelf_file_get_pt_dynamic(elf); \
dyn = (_phdr == NULL) ? elf->data_end : DYN##B(elf->vdata + EGET(_phdr->p_offset)); \
} \
--dyn; \
while ((void *)++dyn < elf->data_end - sizeof(*dyn) && EGET(dyn->d_tag) != DT_NULL)
/* sub-funcs for scanelf_fileat() */
static void scanelf_file_get_symtabs(elfobj *elf, const void **sym, const void **str)
{
/* find the best SHT_DYNSYM and SHT_STRTAB sections */
/* debug sections */
const void *symtab = elf_findsecbyname(elf, ".symtab");
const void *strtab = elf_findsecbyname(elf, ".strtab");
/* runtime sections */
const void *dynsym = elf_findsecbyname(elf, ".dynsym");
const void *dynstr = elf_findsecbyname(elf, ".dynstr");
/*
* If the sections are marked NOBITS, then they don't exist, so we just
* skip them. This let's us work sanely with splitdebug ELFs (rather
* than spewing a lot of "corrupt ELF" messages later on). In malformed
* ELFs, the section might be wrongly set to NOBITS, but screw em.
*
* We need to make sure the debug/runtime sym/str sets are used together
* as they are generated in sync. Trying to mix them won't work.
*/
#define GET_SYMTABS(B) \
const Elf ## B ## _Shdr *esymtab = symtab; \
const Elf ## B ## _Shdr *estrtab = strtab; \
const Elf ## B ## _Shdr *edynsym = dynsym; \
const Elf ## B ## _Shdr *edynstr = dynstr; \
\
if (!VALID_SHDR(elf, esymtab)) \
symtab = NULL; \
if (!VALID_SHDR(elf, edynsym)) \
dynsym = NULL; \
if (!VALID_SHDR(elf, estrtab)) \
strtab = NULL; \
if (!VALID_SHDR(elf, edynstr)) \
dynstr = NULL; \
\
/* Use the set with more symbols if both exist. */ \
if (symtab && dynsym && strtab && dynstr) { \
if (EGET(esymtab->sh_size) > EGET(edynsym->sh_size)) \
goto debug##B; \
else \
goto runtime##B; \
} else if (symtab && strtab) { \
debug##B: \
*sym = symtab; \
*str = strtab; \
return; \
} else if (dynsym && dynstr) { \
runtime##B: \
*sym = dynsym; \
*str = dynstr; \
return; \
} else { \
*sym = *str = NULL; \
}
SCANELF_ELF_SIZED(GET_SYMTABS);
if (*sym && *str)
return;
/*
* damn, they're really going to make us work for it huh?
* reconstruct the section header info out of the dynamic
* tags so we can see what symbols this guy uses at runtime.
*/
#define GET_SYMTABS_DT(B) \
size_t i; \
static Elf ## B ## _Shdr sym_shdr, str_shdr; \
const Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
const Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
Elf ## B ## _Addr vsym, vstr, vhash, vgnu_hash; \
const Elf ## B ## _Dyn *dyn; \
\
/* lookup symbols used at runtime with DT_SYMTAB / DT_STRTAB */ \
vsym = vstr = vhash = vgnu_hash = 0; \
memset(&sym_shdr, 0, sizeof(sym_shdr)); \
memset(&str_shdr, 0, sizeof(str_shdr)); \
\
/* Find the dynamic headers */ \
scanelf_dt_for_each(B, elf, dyn) { \
switch (EGET(dyn->d_tag)) { \
case DT_SYMTAB: vsym = EGET(dyn->d_un.d_val); break; \
case DT_SYMENT: sym_shdr.sh_entsize = dyn->d_un.d_val; break; \
case DT_STRTAB: vstr = EGET(dyn->d_un.d_val); break; \
case DT_STRSZ: str_shdr.sh_size = dyn->d_un.d_val; break; \
case DT_HASH: vhash = EGET(dyn->d_un.d_val); break; \
/*case DT_GNU_HASH: vgnu_hash = EGET(dyn->d_un.d_val); break;*/ \
} \
} \
if (!vsym || !vstr || !(vhash || vgnu_hash)) \
return; \
\
/* calc offset into the ELF by finding the load addr of the syms */ \
for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
Elf ## B ## _Addr vaddr = EGET(phdr[i].p_vaddr); \
Elf ## B ## _Addr filesz = EGET(phdr[i].p_filesz); \
Elf ## B ## _Off offset = EGET(phdr[i].p_offset); \
Elf ## B ## _Off hash_offset = offset + (vhash - vaddr); \
\
if (EGET(phdr[i].p_type) != PT_LOAD) \
continue; \
\
if (!VALID_RANGE(elf, offset, filesz)) \
goto corrupt_hash; \
if (!VALID_RANGE(elf, hash_offset, sizeof(Elf32_Word) * 4)) \
goto corrupt_hash; \
\
if (vhash >= vaddr && vhash < vaddr + filesz) { \
/* Scan the hash table to see how many entries we have */ \
Elf32_Word max_sym_idx = 0; \
const Elf32_Word *hashtbl = elf->vdata + hash_offset; \
Elf32_Word b, nbuckets = EGET(hashtbl[0]); \
Elf32_Word nchains = EGET(hashtbl[1]); \
const Elf32_Word *buckets = &hashtbl[2]; \
const Elf32_Word *chains = &buckets[nbuckets]; \
Elf32_Word sym_idx; \
Elf32_Word chained; \
\
if (!VALID_RANGE(elf, hash_offset, nbuckets * (uint64_t)4)) \
goto corrupt_hash; \
if (!VALID_RANGE(elf, hash_offset, nchains * (uint64_t)4)) \
goto corrupt_hash; \
\
for (b = 0; b < nbuckets; ++b) { \
if (!buckets[b]) \
continue; \
for (sym_idx = buckets[b], chained = 0; \
(sym_idx < nchains && sym_idx && chained <= nchains && \
(void *)&chains[sym_idx] + sizeof(*chains) < elf->data_end); \
sym_idx = chains[sym_idx], ++chained) { \
if (max_sym_idx < sym_idx) \
max_sym_idx = sym_idx; \
} \
if (chained > nchains) \
goto corrupt_hash; \
} \
ESET(sym_shdr.sh_size, sym_shdr.sh_entsize * max_sym_idx); \
} \
\
if (vsym >= vaddr && vsym < vaddr + filesz) { \
const Elf##B##_Shdr *shdr = &sym_shdr; \
ESET(sym_shdr.sh_offset, offset + (vsym - vaddr)); \
if (VALID_SHDR(elf, shdr)) \
*sym = shdr; \
} \
\
if (vstr >= vaddr && vstr < vaddr + filesz) { \
const Elf##B##_Shdr *shdr = &str_shdr; \
ESET(str_shdr.sh_offset, offset + (vstr - vaddr)); \
if (VALID_SHDR(elf, shdr)) \
*str = shdr; \
} \
}
if (elf->phdr)
SCANELF_ELF_SIZED(GET_SYMTABS_DT);
return;
corrupt_hash:
warn("%s: ELF hash table is corrupt", elf->filename);
}
static const char *scanelf_file_pax(elfobj *elf, char *found_pax)
{
static char ret[7];
unsigned long i, shown;
if (!show_pax) return NULL;
shown = 0;
memset(&ret, 0, sizeof(ret));
#define SHOW_PAX(B) \
const Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
const Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
for (i = 0; i < EGET(ehdr->e_phnum); i++) { \
if (EGET(phdr[i].p_type) != PT_PAX_FLAGS) \
continue; \
if (fix_elf && setpax) { \
/* set the paxctl flags */ \
Elf ## B ## _Phdr *wphdr = (void *)&phdr[i]; \
ESET(wphdr->p_flags, setpax); \
} \
if (be_quiet && (EGET(phdr[i].p_flags) == (PF_NOEMUTRAMP | PF_NORANDEXEC))) \
continue; \
memcpy(ret, pax_short_pf_flags(EGET(phdr[i].p_flags)), 6); \
*found_pax = 1; \
++shown; \
break; \
}
if (elf->phdr)
SCANELF_ELF_SIZED(SHOW_PAX);
/* Note: We do not support setting EI_PAX if not PT_PAX_FLAGS
* was found. This is known to break ELFs on glibc systems,
* and mainline PaX has deprecated use of this for a long time.
* We could support changing PT_GNU_STACK, but that doesn't
* seem like it's worth the effort. #411919
*/
/* fall back to EI_PAX if no PT_PAX was found */
if (!*ret) {
const char *paxflags = pax_short_hf_flags(EI_PAX_FLAGS(elf));
if (!be_quiet || (be_quiet && EI_PAX_FLAGS(elf))) {
*found_pax = 1;
return (be_wewy_wewy_quiet ? NULL : paxflags);
}
strcpy(ret, paxflags);
}
if (be_wewy_wewy_quiet || (be_quiet && !shown))
return NULL;
else
return ret;
}
static const char *scanelf_file_phdr(elfobj *elf, char *found_phdr, char *found_relro, char *found_load)
{
static char ret[12];
char *found;
unsigned long i, shown, multi_stack, multi_relro, multi_load;
if (!show_phdr) return NULL;
memcpy(ret, "--- --- ---\0", 12);
shown = 0;
multi_stack = multi_relro = multi_load = 0;
#define NOTE_GNU_STACK ".note.GNU-stack"
#define SHOW_PHDR(B) \
const Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
Elf ## B ## _Off offset; \
uint32_t flags, check_flags; \
if (elf->phdr != NULL) { \
const Elf ## B ## _Phdr *phdr = PHDR ## B (elf->phdr); \
for (i = 0; i < EGET(ehdr->e_phnum); ++i) { \
if (EGET(phdr[i].p_type) == PT_GNU_STACK) { \
if (multi_stack++) \
warnf("%s: multiple PT_GNU_STACK's !?", elf->filename); \
if (file_matches_list(elf->filename, qa_execstack)) \
continue; \
found = found_phdr; \
offset = 0; \
check_flags = PF_X; \
} else if (EGET(phdr[i].p_type) == PT_GNU_RELRO) { \
if (multi_relro++) \
warnf("%s: multiple PT_GNU_RELRO's !?", elf->filename); \
found = found_relro; \
offset = 4; \
check_flags = PF_X; \
} else if (EGET(phdr[i].p_type) == PT_LOAD) { \
if (file_matches_list(elf->filename, qa_wx_load)) \
continue; \
found = found_load; \
offset = 8; \
check_flags = PF_W|PF_X; \
} else \
continue; \
flags = EGET(phdr[i].p_flags); \
if (be_quiet && ((flags & check_flags) != check_flags)) \
continue; \
if ((EGET(phdr[i].p_type) != PT_LOAD) && (fix_elf && ((flags & PF_X) != flags))) { \
Elf ## B ## _Phdr *wphdr = (void *)&phdr[i]; \
ESET(wphdr->p_flags, flags & (PF_X ^ (size_t)-1)); \
ret[3] = ret[7] = '!'; \
flags = EGET(phdr[i].p_flags); \
} \
memcpy(ret+offset, gnu_short_stack_flags(flags), 3); \
*found = 1; \
++shown; \
} \
} else if (elf->shdr != NULL) { \
/* no program headers which means this is prob an object file */ \
const Elf ## B ## _Shdr *shdr = SHDR ## B (elf->shdr); \
uint16_t shstrndx = EGET(ehdr->e_shstrndx); \
const Elf ## B ## _Shdr *strtbl = shdr + shstrndx; \
uint16_t shnum = EGET(ehdr->e_shnum); \
if (shstrndx >= shnum || !VALID_SHDR(elf, strtbl)) \
goto corrupt_shdr; \
/* let's flag -w/+x object files since the final ELF will most likely \
* need write access to the stack (who doesn't !?). so the combined \
* output will bring in +w automatically and that's bad. \
*/ \
check_flags = /*SHF_WRITE|*/SHF_EXECINSTR; \
for (i = 0; i < shnum; ++i) { \
if (EGET(shdr[i].sh_type) != SHT_PROGBITS) continue; \
offset = EGET(strtbl->sh_offset) + EGET(shdr[i].sh_name); \
if (!VALID_RANGE(elf, offset, sizeof(NOTE_GNU_STACK))) \
continue; \
if (!strcmp(elf->data + offset, NOTE_GNU_STACK)) { \
if (multi_stack++) warnf("%s: multiple .note.GNU-stack's !?", elf->filename); \
if (file_matches_list(elf->filename, qa_execstack)) \
continue; \
flags = EGET(shdr[i].sh_flags); \
if (be_quiet && ((flags & check_flags) != check_flags)) \
continue; \
++*found_phdr; \
shown = 1; \
if (flags & SHF_WRITE) ret[0] = 'W'; \
if (flags & SHF_ALLOC) ret[1] = 'A'; \
if (flags & SHF_EXECINSTR) ret[2] = 'X'; \
if (flags & 0xFFFFFFF8) warn("Invalid section flags for GNU-stack"); \
break; \
} \
} \
if (!multi_stack) { \
if (file_matches_list(elf->filename, qa_execstack)) \
return NULL; \
*found_phdr = 1; \
shown = 1; \
memcpy(ret, "!WX", 3); \
} \
}
SCANELF_ELF_SIZED(SHOW_PHDR);
if (be_wewy_wewy_quiet || (be_quiet && !shown))
return NULL;
else
return ret;
corrupt_shdr:
warnf("%s: section table is corrupt", elf->filename);
return NULL;
}
/*
* See if this ELF contains a DT_TEXTREL tag in any of its
* PT_DYNAMIC sections.
*/
static const char *scanelf_file_textrel(elfobj *elf, char *found_textrel)
{
static const char *ret = "TEXTREL";
if (!show_textrel && !show_textrels) return NULL;
if (file_matches_list(elf->filename, qa_textrels)) return NULL;
#define SHOW_TEXTREL(B) \
const Elf ## B ## _Dyn *dyn; \
\
scanelf_dt_for_each(B, elf, dyn) { \
if (EGET(dyn->d_tag) == DT_TEXTREL) { /*dyn->d_tag != DT_FLAGS)*/ \
*found_textrel = 1; \
/*if (dyn->d_un.d_val & DF_TEXTREL)*/ \
return (be_wewy_wewy_quiet ? NULL : ret); \
} \
}
if (elf->phdr)
SCANELF_ELF_SIZED(SHOW_TEXTREL);
if (be_quiet || be_wewy_wewy_quiet)
return NULL;
else
return " - ";
}
/*
* Scan the .text section to see if there are any relocations in it.
* Should rewrite this to check PT_LOAD sections that are marked
* Executable rather than the section named '.text'.
*/
static const char *scanelf_file_textrels(elfobj *elf, char *found_textrels, char *found_textrel)
{
unsigned long r, rmax;
const void *symtab_void, *strtab_void;
if (!show_textrels) return NULL;
/* don't search for TEXTREL's if the ELF doesn't have any */
if (!*found_textrel) scanelf_file_textrel(elf, found_textrel);
if (!*found_textrel) return NULL;
scanelf_file_get_symtabs(elf, &symtab_void, &strtab_void);
#define SHOW_TEXTRELS(B) \
size_t i; \
const Elf ## B ## _Ehdr *ehdr = EHDR ## B (elf->ehdr); \
const Elf ## B ## _Phdr *phdr; \
const Elf ## B ## _Shdr *symtab = SHDR ## B (symtab_void); \
const Elf ## B ## _Shdr *strtab = SHDR ## B (strtab_void); \
const Elf ## B ## _Rel *rel; \
const Elf ## B ## _Rela *rela; \
const Elf ## B ## _Dyn *dyn, *drel, *drelsz, *drelent, *dpltrel; \
uint32_t pltrel; \
Elf ## B ## _Addr load_address = 0; \
Elf ## B ## _Addr file_offset; \
\
/* Walk all the dynamic tags to find relocation info */ \
drel = drelsz = drelent = dpltrel = NULL; \
scanelf_dt_for_each(B, elf, dyn) { \
switch (EGET(dyn->d_tag)) { \
case DT_REL: \
case DT_RELA: \
drel = dyn; \
break; \
case DT_RELSZ: \
case DT_RELASZ: \
drelsz = dyn; \
break; \
case DT_RELENT: \
case DT_RELAENT: \
drelent = dyn; \
break; \
case DT_PLTREL: \
dpltrel = dyn; \
break; \
} \
} \
if (!drel || !drelsz || !drelent || !dpltrel) { \
warnf("ELF is missing relocation information"); \
break; \
} \
phdr = PHDR ## B(elf->phdr); \
/* Lookup load base: byte 0 is mapped at load_address */ \
for (i = 0; i < EGET(ehdr->e_phnum); ++i) { \
/* Only care about loadable segments. */ \
if (EGET(phdr[i].p_type) != PT_LOAD) \
continue; \
/* We search for the first program header to map into memory */ \
if (EGET(phdr[i].p_offset) != 0) \
continue; \
load_address = EGET(phdr[i].p_vaddr); \
} \
switch (EGET(dpltrel->d_un.d_val)) { \
case DT_REL: \
file_offset = EGET(drel->d_un.d_val) - load_address; \
if (!VALID_RANGE(elf, file_offset, sizeof (drel->d_un.d_val))) { \
rel = NULL; \
rela = NULL; \
warn("%s: DT_REL is out of file range", elf->filename); \
break; \
} \
rel = REL##B(elf->vdata + file_offset); \
rela = NULL; \
pltrel = DT_REL; \
break; \
case DT_RELA: \
file_offset = EGET(drel->d_un.d_val) - load_address; \
if (!VALID_RANGE(elf, file_offset, sizeof (drel->d_un.d_val))) { \
rel = NULL; \
rela = NULL; \
warn("%s: DT_RELA is out of file range", elf->filename); \
break; \
} \
rel = NULL; \
rela = RELA##B(elf->vdata + file_offset); \
pltrel = DT_RELA; \
break; \
default: \
warn("Unknown relocation type"); \
rel = NULL; \
rela = NULL; \
break; \
} \
if (!rel && !rela) \
break; \
rmax = EGET(drelsz->d_un.d_val) / EGET(drelent->d_un.d_val); \
\
/* search the program segments for relocations */ \
for (i = 0; i < EGET(ehdr->e_phnum); ++i) { \
Elf ## B ## _Addr vaddr = EGET(phdr[i].p_vaddr); \
uint ## B ## _t memsz = EGET(phdr[i].p_memsz); \
\
/* Only care about loadable segments. */ \
if (EGET(phdr[i].p_type) != PT_LOAD) \
continue; \
/* Only care about executable segments. */ \
if ((EGET(phdr[i].p_flags) & PF_X) != PF_X) \
continue; \
\
/* now see if any of the relocs touch this segment */ \
for (r = 0; r < rmax; ++r) { \
unsigned long sym_max; \
Elf ## B ## _Addr offset_tmp; \
const Elf ## B ## _Sym *func; \
const Elf ## B ## _Sym *sym; \
Elf ## B ## _Addr r_offset; \
uint ## B ## _t r_info; \
if (pltrel == DT_REL) { \
r_offset = EGET(rel[r].r_offset); \
r_info = EGET(rel[r].r_info); \
} else { \
r_offset = EGET(rela[r].r_offset); \
r_info = EGET(rela[r].r_info); \
} \
/* make sure this relocation is inside of the .text */ \
if (r_offset < vaddr || r_offset >= vaddr + memsz) { \
if (be_verbose <= 2) continue; \
} else \
*found_textrels = 1; \
/* locate this relocation symbol name */ \
sym = SYM ## B (elf->vdata + EGET(symtab->sh_offset)); \
if ((void*)sym > elf->data_end) { \
warn("%s: corrupt ELF symbol", elf->filename); \
continue; \
} \
sym_max = ELF ## B ## _R_SYM(r_info); \
if (sym_max * EGET(symtab->sh_entsize) < symtab->sh_size) \
sym += sym_max; \
else \
sym = NULL; \
sym_max = EGET(symtab->sh_size) / EGET(symtab->sh_entsize); \
/* show the raw details about this reloc */ \
printf(" %s: ", elf->base_filename); \
if (!strtab) \
printf("(missing symbols)"); \
else if (sym && sym->st_name) \
printf("%s", elf->data + EGET(strtab->sh_offset) + EGET(sym->st_name)); \
else \
printf("(memory/data?)"); \
printf(" [r_offset=0x%lX]", (unsigned long)r_offset); \
printf(" r_type=%lu", (unsigned long)ELF ## B ## _ST_TYPE(r_info)); \
/* now try to find the closest symbol that this rel is probably in */ \
sym = SYM ## B (elf->vdata + EGET(symtab->sh_offset)); \
func = NULL; \
offset_tmp = 0; \
while (sym_max--) { \
if (EGET(sym->st_value) < r_offset && EGET(sym->st_value) > offset_tmp) { \
func = sym; \
offset_tmp = EGET(sym->st_value); \
} \
++sym; \
} \
printf(" in "); \
if (func && func->st_name) { \
if (strtab) { \
const char *func_name = elf->data + EGET(strtab->sh_offset) + EGET(func->st_name); \
if (r_offset > EGET(func->st_size)) \
printf("(optimized out: previous %s)", func_name); \
else \
printf("%s", func_name); \
} else \
printf("(missing symbols)"); \
} else \
printf("(optimized out?)"); \
printf(" [closest_prev_sym=0x%lX]\n", (unsigned long)offset_tmp); \
if (be_verbose && objdump && func) { \
Elf ## B ## _Addr end_addr = offset_tmp + EGET(func->st_size); \
char *sysbuf; \
int ret; \
if (end_addr < r_offset) \
/* not uncommon when things are optimized out */ \
end_addr = r_offset + 0x100; \
ret = asprintf( \
&sysbuf, \
"%s -r -R -d -w -l --start-address=0x%lX --stop-address=0x%lX %s | " \
"grep --color -i -C 3 '.*[[:space:]]%lX:[[:space:]]*R_.*'\n", \
objdump, \
(unsigned long)offset_tmp, \
(unsigned long)end_addr, \
elf->filename, \
(unsigned long)r_offset); \
if (ret < 0) \
errp("asprintf() failed"); \
fflush(stdout); \
if (system(sysbuf)) {/* don't care */} \
fflush(stdout); \
free(sysbuf); \
} \
} \
}
if (symtab_void && elf->phdr)
SCANELF_ELF_SIZED(SHOW_TEXTRELS);
if (!*found_textrels)
warnf("ELF %s has TEXTREL markings but doesn't appear to have any real TEXTREL's !?", elf->filename);
return NULL;
}
static void rpath_security_checks(elfobj *elf, const char *item, const char *dt_type)
{
struct stat st;
switch (*item) {
case '/': break;
case '.':
warnf("Security problem with relative %s '%s' in %s", dt_type, item, elf->filename);
break;
case ':':
case '\0':
warnf("Security problem NULL %s in %s", dt_type, elf->filename);
break;
case '$':
if (fstat(elf->fd, &st) != -1)
if ((st.st_mode & S_ISUID) || (st.st_mode & S_ISGID))
warnf("Security problem with %s='%s' in %s with mode set of %o",
dt_type, item, elf->filename, (unsigned int) st.st_mode & 07777);
break;
default:
warnf("Maybe? sec problem with %s='%s' in %s", dt_type, item, elf->filename);
break;
}
if (fix_elf)
warnf("Note: RPATH has been automatically fixed, but this should be fixed in the package itself");
}
static void scanelf_file_rpath(elfobj *elf, char *found_rpath, char **ret, size_t *ret_len)
{
const char *rpath, *runpath, **r;
const void *strtab_void;
if (!show_rpath) return;
/*
* TODO: Switch to the string table found via dynamic tags.
* Note: We can't use scanelf_file_get_symtabs as these strings are
* *only* found in dynstr and not in .strtab.
*/
strtab_void = elf_findsecbyname(elf, ".dynstr");
rpath = runpath = NULL;
#define SHOW_RPATH(B) \
const Elf ## B ## _Dyn *dyn; \
const Elf ## B ## _Shdr *strtab = SHDR ## B (strtab_void); \
Elf ## B ## _Off offset; \
Elf ## B ## _Xword word; \
\
/* Just scan dynamic RPATH/RUNPATH headers */ \
scanelf_dt_for_each(B, elf, dyn) { \
word = EGET(dyn->d_tag); \
if (word == DT_RPATH) { \
r = &rpath; \
} else if (word == DT_RUNPATH) { \
r = &runpath; \
} else { \
continue; \
} \
/* Verify the memory is somewhat sane */ \
offset = EGET(strtab->sh_offset) + EGET(dyn->d_un.d_ptr); \
if (offset < (Elf ## B ## _Off)elf->len) { \
if (*r) warn("ELF has multiple %s's !?", get_elfdtype(word)); \
*r = elf->data + offset; \
/* cache the length in case we need to nuke this section later on */ \
if (fix_elf) \
offset = strlen(*r); \
/* If quiet, don't output paths in ld.so.conf */ \
if (be_quiet) { \
size_t len; \
const char *start, *end; \
/* note that we only 'chop' off leading known paths. */ \
/* since *r is read-only memory, we can only move the ptr forward. */ \
start = *r; \
/* scan each path in : delimited list */ \
while (start) { \
rpath_security_checks(elf, start, get_elfdtype(word)); \
end = strchr(start, ':'); \
len = (end ? (size_t)(end - start) : strlen(start)); \
if (use_ldcache) { \
size_t n; \
const char *ldpath; \
array_for_each(ldpaths, n, ldpath) \
if (!strncmp(ldpath, start, len) && !ldpath[len]) { \
*r = end; \
/* corner case ... if RPATH reads "/usr/lib:", we want \
* to show ':' rather than '' */ \
if (end && end[1] != '\0') \
(*r)++; \
break; \
} \
} \
if (!*r || !end) \
break; \
else \
start = start + len + 1; \
} \
} \
if (*r) { \
if (fix_elf > 2 || (fix_elf && **r == '\0')) { \
/* just nuke it */ \
nuke_it##B: { \
/* We have to cast away the const. \
* We know we mapped the backing memory as writable. */ \
Elf ## B ## _Dyn *wdyn = (void *)dyn; \
memset((void *)*r, 0x00, offset); \
*r = NULL; \
ESET(wdyn->d_tag, DT_DEBUG); \
ESET(wdyn->d_un.d_ptr, 0); \
} \
} else if (fix_elf) { \
/* try to clean "bad" paths */ \
size_t len, tmpdir_len; \
char *start, *end; \
const char *tmpdir; \
start = (void *)*r; \
tmpdir = (getenv("TMPDIR") ? : "."); \
tmpdir_len = strlen(tmpdir); \
while (1) { \
end = strchr(start, ':'); \
if (start == end) { \
eat_this_path##B: \
len = strlen(end); \
memmove(start, end+1, len); \
start[len-1] = '\0'; \
end = start - 1; \
} else if (tmpdir && !strncmp(start, tmpdir, tmpdir_len)) { \
if (!end) { \
if (start == *r) \
goto nuke_it##B; \
*--start = '\0'; \
} else \
goto eat_this_path##B; \
} \
if (!end) \
break; \
start = end + 1; \
} \
if (**r == '\0') \
goto nuke_it##B; \
} \
if (*r) \
*found_rpath = 1; \
} \
} \
}
if (elf->phdr && strtab_void)
SCANELF_ELF_SIZED(SHOW_RPATH);
if (be_wewy_wewy_quiet) return;
if (rpath && runpath) {
if (!strcmp(rpath, runpath)) {
xstrcat(ret, runpath, ret_len);
} else {
fprintf(stderr, "RPATH [%s] != RUNPATH [%s]\n", rpath, runpath);
xchrcat(ret, '{', ret_len);
xstrcat(ret, rpath, ret_len);
xchrcat(ret, ',', ret_len);
xstrcat(ret, runpath, ret_len);
xchrcat(ret, '}', ret_len);
}
} else if (rpath || runpath)
xstrcat(ret, (runpath ? runpath : rpath), ret_len);
else if (!be_quiet)
xstrcat(ret, " - ", ret_len);
}
static char *lookup_config_lib(const char *fname)
{
static char buf[__PAX_UTILS_PATH_MAX] = "";
const char *ldpath;
size_t n;
array_for_each(ldpaths, n, ldpath) {
snprintf(buf, sizeof(buf), "%s/%s", root_rel_path(ldpath), fname);
if (faccessat(root_fd, buf, F_OK, AT_SYMLINK_NOFOLLOW) == 0)
return buf;
}
return NULL;
}
static const char *scanelf_file_needed_lib(elfobj *elf, char *found_needed, char *found_lib, int op, char **ret, size_t *ret_len)
{
const char *needed;
const void *strtab_void;
char *p;
/*
* -n -> op==0 -> print all
* -N -> op==1 -> print requested
*/
if ((op == 0 && !show_needed) || (op == 1 && !find_lib))
return NULL;
/*
* TODO: Switch to the string table found via dynamic tags.
* Note: We can't use scanelf_file_get_symtabs as these strings are
* *only* found in dynstr and not in .strtab.
*/
strtab_void = elf_findsecbyname(elf, ".dynstr");
#define SHOW_NEEDED(B) \
const Elf ## B ## _Dyn *dyn; \
const Elf ## B ## _Shdr *strtab = SHDR ## B (strtab_void); \
size_t matched = 0; \
\
/* Walk all the dynamic tags to find NEEDED entries */ \
scanelf_dt_for_each(B, elf, dyn) { \
if (EGET(dyn->d_tag) == DT_NEEDED) { \
Elf ## B ## _Off offset = EGET(strtab->sh_offset) + EGET(dyn->d_un.d_ptr); \
if (offset >= (Elf ## B ## _Off)elf->len) \
continue; \
needed = elf->data + offset; \
if (op == 0) { \
/* -n -> print all entries */ \
if (!be_wewy_wewy_quiet) { \
if (*found_needed) xchrcat(ret, ',', ret_len); \
if (use_ldpath) { \
if ((p = lookup_config_lib(needed)) != NULL) \
needed = p; \
} else if (use_ldcache) { \
if ((p = ldso_cache_lookup_lib(elf, needed)) != NULL) \
needed = p; \
} \
xstrcat(ret, needed, ret_len); \
} \
*found_needed = 1; \
} else { \
/* -N -> print matching entries */ \
size_t n; \
const char *find_lib_name; \
\
array_for_each(find_lib_arr, n, find_lib_name) { \