Commit | Line | Data |
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91007045 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
9b07e27f SE |
2 | /* |
3 | * genelf.c | |
4 | * Copyright (C) 2014, Google, Inc | |
5 | * | |
6 | * Contributed by: | |
7 | * Stephane Eranian <eranian@gmail.com> | |
9b07e27f SE |
8 | */ |
9 | ||
10 | #include <sys/types.h> | |
9b07e27f SE |
11 | #include <stddef.h> |
12 | #include <libelf.h> | |
13 | #include <string.h> | |
14 | #include <stdlib.h> | |
91854f9a | 15 | #include <unistd.h> |
9b07e27f | 16 | #include <inttypes.h> |
9b07e27f SE |
17 | #include <fcntl.h> |
18 | #include <err.h> | |
621cb4e7 | 19 | #ifdef HAVE_DWARF_SUPPORT |
9b07e27f | 20 | #include <dwarf.h> |
621cb4e7 | 21 | #endif |
9b07e27f | 22 | |
9b07e27f SE |
23 | #include "genelf.h" |
24 | #include "../util/jitdump.h" | |
91854f9a | 25 | #include <linux/compiler.h> |
9b07e27f | 26 | |
5fef5f3f ACM |
27 | #ifndef NT_GNU_BUILD_ID |
28 | #define NT_GNU_BUILD_ID 3 | |
29 | #endif | |
30 | ||
9b07e27f SE |
31 | #define BUILD_ID_URANDOM /* different uuid for each run */ |
32 | ||
91cea6be | 33 | #ifdef HAVE_LIBCRYPTO_SUPPORT |
9b07e27f SE |
34 | |
35 | #define BUILD_ID_MD5 | |
36 | #undef BUILD_ID_SHA /* does not seem to work well when linked with Java */ | |
37 | #undef BUILD_ID_URANDOM /* different uuid for each run */ | |
38 | ||
39 | #ifdef BUILD_ID_SHA | |
40 | #include <openssl/sha.h> | |
41 | #endif | |
42 | ||
43 | #ifdef BUILD_ID_MD5 | |
6ea9da51 | 44 | #include <openssl/evp.h> |
9b07e27f SE |
45 | #include <openssl/md5.h> |
46 | #endif | |
47 | #endif | |
48 | ||
49 | ||
50 | typedef struct { | |
51 | unsigned int namesz; /* Size of entry's owner string */ | |
52 | unsigned int descsz; /* Size of the note descriptor */ | |
53 | unsigned int type; /* Interpretation of the descriptor */ | |
54 | char name[0]; /* Start of the name+desc data */ | |
55 | } Elf_Note; | |
56 | ||
57 | struct options { | |
58 | char *output; | |
59 | int fd; | |
60 | }; | |
61 | ||
62 | static char shd_string_table[] = { | |
63 | 0, | |
64 | '.', 't', 'e', 'x', 't', 0, /* 1 */ | |
65 | '.', 's', 'h', 's', 't', 'r', 't', 'a', 'b', 0, /* 7 */ | |
66 | '.', 's', 'y', 'm', 't', 'a', 'b', 0, /* 17 */ | |
67 | '.', 's', 't', 'r', 't', 'a', 'b', 0, /* 25 */ | |
68 | '.', 'n', 'o', 't', 'e', '.', 'g', 'n', 'u', '.', 'b', 'u', 'i', 'l', 'd', '-', 'i', 'd', 0, /* 33 */ | |
69 | '.', 'd', 'e', 'b', 'u', 'g', '_', 'l', 'i', 'n', 'e', 0, /* 52 */ | |
70 | '.', 'd', 'e', 'b', 'u', 'g', '_', 'i', 'n', 'f', 'o', 0, /* 64 */ | |
71 | '.', 'd', 'e', 'b', 'u', 'g', '_', 'a', 'b', 'b', 'r', 'e', 'v', 0, /* 76 */ | |
086f9f3d SS |
72 | '.', 'e', 'h', '_', 'f', 'r', 'a', 'm', 'e', '_', 'h', 'd', 'r', 0, /* 90 */ |
73 | '.', 'e', 'h', '_', 'f', 'r', 'a', 'm', 'e', 0, /* 104 */ | |
9b07e27f SE |
74 | }; |
75 | ||
76 | static struct buildid_note { | |
77 | Elf_Note desc; /* descsz: size of build-id, must be multiple of 4 */ | |
78 | char name[4]; /* GNU\0 */ | |
79 | char build_id[20]; | |
80 | } bnote; | |
81 | ||
82 | static Elf_Sym symtab[]={ | |
83 | /* symbol 0 MUST be the undefined symbol */ | |
84 | { .st_name = 0, /* index in sym_string table */ | |
85 | .st_info = ELF_ST_TYPE(STT_NOTYPE), | |
86 | .st_shndx = 0, /* for now */ | |
87 | .st_value = 0x0, | |
88 | .st_other = ELF_ST_VIS(STV_DEFAULT), | |
89 | .st_size = 0, | |
90 | }, | |
91 | { .st_name = 1, /* index in sym_string table */ | |
92 | .st_info = ELF_ST_BIND(STB_LOCAL) | ELF_ST_TYPE(STT_FUNC), | |
93 | .st_shndx = 1, | |
94 | .st_value = 0, /* for now */ | |
95 | .st_other = ELF_ST_VIS(STV_DEFAULT), | |
96 | .st_size = 0, /* for now */ | |
97 | } | |
98 | }; | |
99 | ||
100 | #ifdef BUILD_ID_URANDOM | |
101 | static void | |
102 | gen_build_id(struct buildid_note *note, | |
103 | unsigned long load_addr __maybe_unused, | |
104 | const void *code __maybe_unused, | |
105 | size_t csize __maybe_unused) | |
106 | { | |
107 | int fd; | |
108 | size_t sz = sizeof(note->build_id); | |
109 | ssize_t sret; | |
110 | ||
111 | fd = open("/dev/urandom", O_RDONLY); | |
112 | if (fd == -1) | |
24690761 | 113 | err(1, "cannot access /dev/urandom for buildid"); |
9b07e27f SE |
114 | |
115 | sret = read(fd, note->build_id, sz); | |
116 | ||
117 | close(fd); | |
118 | ||
119 | if (sret != (ssize_t)sz) | |
120 | memset(note->build_id, 0, sz); | |
121 | } | |
122 | #endif | |
123 | ||
124 | #ifdef BUILD_ID_SHA | |
125 | static void | |
126 | gen_build_id(struct buildid_note *note, | |
127 | unsigned long load_addr __maybe_unused, | |
128 | const void *code, | |
129 | size_t csize) | |
130 | { | |
131 | if (sizeof(note->build_id) < SHA_DIGEST_LENGTH) | |
132 | errx(1, "build_id too small for SHA1"); | |
133 | ||
134 | SHA1(code, csize, (unsigned char *)note->build_id); | |
135 | } | |
136 | #endif | |
137 | ||
138 | #ifdef BUILD_ID_MD5 | |
139 | static void | |
140 | gen_build_id(struct buildid_note *note, unsigned long load_addr, const void *code, size_t csize) | |
141 | { | |
6ea9da51 | 142 | EVP_MD_CTX *mdctx; |
9b07e27f SE |
143 | |
144 | if (sizeof(note->build_id) < 16) | |
145 | errx(1, "build_id too small for MD5"); | |
146 | ||
6ea9da51 ZT |
147 | mdctx = EVP_MD_CTX_new(); |
148 | if (!mdctx) | |
149 | errx(2, "failed to create EVP_MD_CTX"); | |
150 | ||
151 | EVP_DigestInit_ex(mdctx, EVP_md5(), NULL); | |
152 | EVP_DigestUpdate(mdctx, &load_addr, sizeof(load_addr)); | |
153 | EVP_DigestUpdate(mdctx, code, csize); | |
154 | EVP_DigestFinal_ex(mdctx, (unsigned char *)note->build_id, NULL); | |
155 | EVP_MD_CTX_free(mdctx); | |
9b07e27f SE |
156 | } |
157 | #endif | |
158 | ||
086f9f3d SS |
159 | static int |
160 | jit_add_eh_frame_info(Elf *e, void* unwinding, uint64_t unwinding_header_size, | |
161 | uint64_t unwinding_size, uint64_t base_offset) | |
162 | { | |
163 | Elf_Data *d; | |
164 | Elf_Scn *scn; | |
165 | Elf_Shdr *shdr; | |
166 | uint64_t unwinding_table_size = unwinding_size - unwinding_header_size; | |
167 | ||
168 | /* | |
169 | * setup eh_frame section | |
170 | */ | |
171 | scn = elf_newscn(e); | |
172 | if (!scn) { | |
173 | warnx("cannot create section"); | |
174 | return -1; | |
175 | } | |
176 | ||
177 | d = elf_newdata(scn); | |
178 | if (!d) { | |
179 | warnx("cannot get new data"); | |
180 | return -1; | |
181 | } | |
182 | ||
183 | d->d_align = 8; | |
184 | d->d_off = 0LL; | |
185 | d->d_buf = unwinding; | |
186 | d->d_type = ELF_T_BYTE; | |
187 | d->d_size = unwinding_table_size; | |
188 | d->d_version = EV_CURRENT; | |
189 | ||
190 | shdr = elf_getshdr(scn); | |
191 | if (!shdr) { | |
192 | warnx("cannot get section header"); | |
193 | return -1; | |
194 | } | |
195 | ||
196 | shdr->sh_name = 104; | |
197 | shdr->sh_type = SHT_PROGBITS; | |
198 | shdr->sh_addr = base_offset; | |
199 | shdr->sh_flags = SHF_ALLOC; | |
200 | shdr->sh_entsize = 0; | |
201 | ||
202 | /* | |
203 | * setup eh_frame_hdr section | |
204 | */ | |
205 | scn = elf_newscn(e); | |
206 | if (!scn) { | |
207 | warnx("cannot create section"); | |
208 | return -1; | |
209 | } | |
210 | ||
211 | d = elf_newdata(scn); | |
212 | if (!d) { | |
213 | warnx("cannot get new data"); | |
214 | return -1; | |
215 | } | |
216 | ||
217 | d->d_align = 4; | |
218 | d->d_off = 0LL; | |
219 | d->d_buf = unwinding + unwinding_table_size; | |
220 | d->d_type = ELF_T_BYTE; | |
221 | d->d_size = unwinding_header_size; | |
222 | d->d_version = EV_CURRENT; | |
223 | ||
224 | shdr = elf_getshdr(scn); | |
225 | if (!shdr) { | |
226 | warnx("cannot get section header"); | |
227 | return -1; | |
228 | } | |
229 | ||
230 | shdr->sh_name = 90; | |
231 | shdr->sh_type = SHT_PROGBITS; | |
232 | shdr->sh_addr = base_offset + unwinding_table_size; | |
233 | shdr->sh_flags = SHF_ALLOC; | |
234 | shdr->sh_entsize = 0; | |
235 | ||
236 | return 0; | |
237 | } | |
238 | ||
9b07e27f SE |
239 | /* |
240 | * fd: file descriptor open for writing for the output file | |
241 | * load_addr: code load address (could be zero, just used for buildid) | |
242 | * sym: function name (for native code - used as the symbol) | |
243 | * code: the native code | |
244 | * csize: the code size in bytes | |
245 | */ | |
246 | int | |
247 | jit_write_elf(int fd, uint64_t load_addr, const char *sym, | |
598b7c69 | 248 | const void *code, int csize, |
086f9f3d SS |
249 | void *debug __maybe_unused, int nr_debug_entries __maybe_unused, |
250 | void *unwinding, uint64_t unwinding_header_size, uint64_t unwinding_size) | |
9b07e27f SE |
251 | { |
252 | Elf *e; | |
253 | Elf_Data *d; | |
254 | Elf_Scn *scn; | |
255 | Elf_Ehdr *ehdr; | |
babd0438 | 256 | Elf_Phdr *phdr; |
9b07e27f | 257 | Elf_Shdr *shdr; |
086f9f3d | 258 | uint64_t eh_frame_base_offset; |
9b07e27f SE |
259 | char *strsym = NULL; |
260 | int symlen; | |
261 | int retval = -1; | |
262 | ||
263 | if (elf_version(EV_CURRENT) == EV_NONE) { | |
264 | warnx("ELF initialization failed"); | |
265 | return -1; | |
266 | } | |
267 | ||
268 | e = elf_begin(fd, ELF_C_WRITE, NULL); | |
269 | if (!e) { | |
270 | warnx("elf_begin failed"); | |
271 | goto error; | |
272 | } | |
273 | ||
274 | /* | |
275 | * setup ELF header | |
276 | */ | |
277 | ehdr = elf_newehdr(e); | |
278 | if (!ehdr) { | |
279 | warnx("cannot get ehdr"); | |
280 | goto error; | |
281 | } | |
282 | ||
283 | ehdr->e_ident[EI_DATA] = GEN_ELF_ENDIAN; | |
284 | ehdr->e_ident[EI_CLASS] = GEN_ELF_CLASS; | |
285 | ehdr->e_machine = GEN_ELF_ARCH; | |
286 | ehdr->e_type = ET_DYN; | |
287 | ehdr->e_entry = GEN_ELF_TEXT_OFFSET; | |
288 | ehdr->e_version = EV_CURRENT; | |
086f9f3d | 289 | ehdr->e_shstrndx= unwinding ? 4 : 2; /* shdr index for section name */ |
9b07e27f | 290 | |
babd0438 LH |
291 | /* |
292 | * setup program header | |
293 | */ | |
294 | phdr = elf_newphdr(e, 1); | |
295 | phdr[0].p_type = PT_LOAD; | |
1af47890 NK |
296 | phdr[0].p_offset = GEN_ELF_TEXT_OFFSET; |
297 | phdr[0].p_vaddr = GEN_ELF_TEXT_OFFSET; | |
298 | phdr[0].p_paddr = GEN_ELF_TEXT_OFFSET; | |
babd0438 LH |
299 | phdr[0].p_filesz = csize; |
300 | phdr[0].p_memsz = csize; | |
301 | phdr[0].p_flags = PF_X | PF_R; | |
302 | phdr[0].p_align = 8; | |
303 | ||
9b07e27f SE |
304 | /* |
305 | * setup text section | |
306 | */ | |
307 | scn = elf_newscn(e); | |
308 | if (!scn) { | |
309 | warnx("cannot create section"); | |
310 | goto error; | |
311 | } | |
312 | ||
313 | d = elf_newdata(scn); | |
314 | if (!d) { | |
315 | warnx("cannot get new data"); | |
316 | goto error; | |
317 | } | |
318 | ||
319 | d->d_align = 16; | |
320 | d->d_off = 0LL; | |
321 | d->d_buf = (void *)code; | |
322 | d->d_type = ELF_T_BYTE; | |
323 | d->d_size = csize; | |
324 | d->d_version = EV_CURRENT; | |
325 | ||
326 | shdr = elf_getshdr(scn); | |
327 | if (!shdr) { | |
328 | warnx("cannot get section header"); | |
329 | goto error; | |
330 | } | |
331 | ||
332 | shdr->sh_name = 1; | |
333 | shdr->sh_type = SHT_PROGBITS; | |
334 | shdr->sh_addr = GEN_ELF_TEXT_OFFSET; | |
335 | shdr->sh_flags = SHF_EXECINSTR | SHF_ALLOC; | |
336 | shdr->sh_entsize = 0; | |
337 | ||
086f9f3d SS |
338 | /* |
339 | * Setup .eh_frame_hdr and .eh_frame | |
340 | */ | |
341 | if (unwinding) { | |
342 | eh_frame_base_offset = ALIGN_8(GEN_ELF_TEXT_OFFSET + csize); | |
343 | retval = jit_add_eh_frame_info(e, unwinding, | |
344 | unwinding_header_size, unwinding_size, | |
345 | eh_frame_base_offset); | |
346 | if (retval) | |
347 | goto error; | |
e8a6430f | 348 | retval = -1; |
086f9f3d SS |
349 | } |
350 | ||
9b07e27f SE |
351 | /* |
352 | * setup section headers string table | |
353 | */ | |
354 | scn = elf_newscn(e); | |
355 | if (!scn) { | |
356 | warnx("cannot create section"); | |
357 | goto error; | |
358 | } | |
359 | ||
360 | d = elf_newdata(scn); | |
361 | if (!d) { | |
362 | warnx("cannot get new data"); | |
363 | goto error; | |
364 | } | |
365 | ||
366 | d->d_align = 1; | |
367 | d->d_off = 0LL; | |
368 | d->d_buf = shd_string_table; | |
369 | d->d_type = ELF_T_BYTE; | |
370 | d->d_size = sizeof(shd_string_table); | |
371 | d->d_version = EV_CURRENT; | |
372 | ||
373 | shdr = elf_getshdr(scn); | |
374 | if (!shdr) { | |
375 | warnx("cannot get section header"); | |
376 | goto error; | |
377 | } | |
378 | ||
379 | shdr->sh_name = 7; /* offset of '.shstrtab' in shd_string_table */ | |
380 | shdr->sh_type = SHT_STRTAB; | |
381 | shdr->sh_flags = 0; | |
382 | shdr->sh_entsize = 0; | |
383 | ||
384 | /* | |
385 | * setup symtab section | |
386 | */ | |
387 | symtab[1].st_size = csize; | |
388 | symtab[1].st_value = GEN_ELF_TEXT_OFFSET; | |
389 | ||
390 | scn = elf_newscn(e); | |
391 | if (!scn) { | |
392 | warnx("cannot create section"); | |
393 | goto error; | |
394 | } | |
395 | ||
396 | d = elf_newdata(scn); | |
397 | if (!d) { | |
398 | warnx("cannot get new data"); | |
399 | goto error; | |
400 | } | |
401 | ||
402 | d->d_align = 8; | |
403 | d->d_off = 0LL; | |
404 | d->d_buf = symtab; | |
405 | d->d_type = ELF_T_SYM; | |
406 | d->d_size = sizeof(symtab); | |
407 | d->d_version = EV_CURRENT; | |
408 | ||
409 | shdr = elf_getshdr(scn); | |
410 | if (!shdr) { | |
411 | warnx("cannot get section header"); | |
412 | goto error; | |
413 | } | |
414 | ||
415 | shdr->sh_name = 17; /* offset of '.symtab' in shd_string_table */ | |
416 | shdr->sh_type = SHT_SYMTAB; | |
417 | shdr->sh_flags = 0; | |
418 | shdr->sh_entsize = sizeof(Elf_Sym); | |
086f9f3d | 419 | shdr->sh_link = unwinding ? 6 : 4; /* index of .strtab section */ |
9b07e27f SE |
420 | |
421 | /* | |
422 | * setup symbols string table | |
423 | * 2 = 1 for 0 in 1st entry, 1 for the 0 at end of symbol for 2nd entry | |
424 | */ | |
425 | symlen = 2 + strlen(sym); | |
426 | strsym = calloc(1, symlen); | |
427 | if (!strsym) { | |
428 | warnx("cannot allocate strsym"); | |
429 | goto error; | |
430 | } | |
431 | strcpy(strsym + 1, sym); | |
432 | ||
433 | scn = elf_newscn(e); | |
434 | if (!scn) { | |
435 | warnx("cannot create section"); | |
436 | goto error; | |
437 | } | |
438 | ||
439 | d = elf_newdata(scn); | |
440 | if (!d) { | |
441 | warnx("cannot get new data"); | |
442 | goto error; | |
443 | } | |
444 | ||
445 | d->d_align = 1; | |
446 | d->d_off = 0LL; | |
447 | d->d_buf = strsym; | |
448 | d->d_type = ELF_T_BYTE; | |
449 | d->d_size = symlen; | |
450 | d->d_version = EV_CURRENT; | |
451 | ||
452 | shdr = elf_getshdr(scn); | |
453 | if (!shdr) { | |
454 | warnx("cannot get section header"); | |
455 | goto error; | |
456 | } | |
457 | ||
458 | shdr->sh_name = 25; /* offset in shd_string_table */ | |
459 | shdr->sh_type = SHT_STRTAB; | |
460 | shdr->sh_flags = 0; | |
461 | shdr->sh_entsize = 0; | |
462 | ||
463 | /* | |
464 | * setup build-id section | |
465 | */ | |
466 | scn = elf_newscn(e); | |
467 | if (!scn) { | |
468 | warnx("cannot create section"); | |
469 | goto error; | |
470 | } | |
471 | ||
472 | d = elf_newdata(scn); | |
473 | if (!d) { | |
474 | warnx("cannot get new data"); | |
475 | goto error; | |
476 | } | |
477 | ||
478 | /* | |
479 | * build-id generation | |
480 | */ | |
481 | gen_build_id(&bnote, load_addr, code, csize); | |
482 | bnote.desc.namesz = sizeof(bnote.name); /* must include 0 termination */ | |
483 | bnote.desc.descsz = sizeof(bnote.build_id); | |
484 | bnote.desc.type = NT_GNU_BUILD_ID; | |
485 | strcpy(bnote.name, "GNU"); | |
486 | ||
487 | d->d_align = 4; | |
488 | d->d_off = 0LL; | |
489 | d->d_buf = &bnote; | |
490 | d->d_type = ELF_T_BYTE; | |
491 | d->d_size = sizeof(bnote); | |
492 | d->d_version = EV_CURRENT; | |
493 | ||
494 | shdr = elf_getshdr(scn); | |
495 | if (!shdr) { | |
496 | warnx("cannot get section header"); | |
497 | goto error; | |
498 | } | |
499 | ||
500 | shdr->sh_name = 33; /* offset in shd_string_table */ | |
501 | shdr->sh_type = SHT_NOTE; | |
502 | shdr->sh_addr = 0x0; | |
503 | shdr->sh_flags = SHF_ALLOC; | |
504 | shdr->sh_size = sizeof(bnote); | |
505 | shdr->sh_entsize = 0; | |
506 | ||
621cb4e7 | 507 | #ifdef HAVE_DWARF_SUPPORT |
598b7c69 SE |
508 | if (debug && nr_debug_entries) { |
509 | retval = jit_add_debug_info(e, load_addr, debug, nr_debug_entries); | |
510 | if (retval) | |
511 | goto error; | |
621cb4e7 MD |
512 | } else |
513 | #endif | |
514 | { | |
598b7c69 SE |
515 | if (elf_update(e, ELF_C_WRITE) < 0) { |
516 | warnx("elf_update 4 failed"); | |
517 | goto error; | |
518 | } | |
9b07e27f SE |
519 | } |
520 | ||
521 | retval = 0; | |
522 | error: | |
523 | (void)elf_end(e); | |
524 | ||
525 | free(strsym); | |
526 | ||
527 | ||
528 | return retval; | |
529 | } |