Bug Summary

File:util/cbfstool/elfheaders.c
Warning:line 990, column 18
The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-unknown-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name elfheaders.c -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 2 -pic-is-pie -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/home/coreboot/node-root/workspace/coreboot_scanbuild -resource-dir /opt/xgcc/lib/clang/17 -include /home/coreboot/node-root/workspace/coreboot_scanbuild/src/commonlib/bsd/include/commonlib/bsd/compiler.h -include /home/coreboot/node-root/workspace/coreboot_scanbuild/src/commonlib/bsd/include/commonlib/bsd/compiler.h -D _DEFAULT_SOURCE -D _BSD_SOURCE -D _SVID_SOURCE -D _GNU_SOURCE -I /home/coreboot/node-root/workspace/coreboot_scanbuild/util/cbfstool/flashmap -I /home/coreboot/node-root/workspace/coreboot_scanbuild/util/cbfstool -I /cb-build/coreboot_scanbuild.0/sharedutils/cbfstool -I /home/coreboot/node-root/workspace/coreboot_scanbuild/src/commonlib/include -I /home/coreboot/node-root/workspace/coreboot_scanbuild/src/commonlib/bsd/include -I 3rdparty/vboot/firmware/include -I 3rdparty/vboot/firmware/2lib/include -I 3rdparty/vboot/host/include -I 3rdparty/vboot/host/lib/include -I /home/coreboot/node-root/workspace/coreboot_scanbuild/src -I /home/coreboot/node-root/workspace/coreboot_scanbuild/src/vendorcode/intel/edk2/uefi_2.4/MdePkg/Include -internal-isystem /opt/xgcc/lib/clang/17/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/13/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -source-date-epoch 1714465709 -O2 -Wwrite-strings -std=c11 -fconst-strings -fdebug-compilation-dir=/home/coreboot/node-root/workspace/coreboot_scanbuild -ferror-limit 19 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-opt-analyze-headers -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /cb-build/coreboot_scanbuild.0/sharedutils-scanbuildtmp/2024-05-02-073004-2299942-1 -x c /home/coreboot/node-root/workspace/coreboot_scanbuild/util/cbfstool/elfheaders.c
1/* elf header parsing */
2/* SPDX-License-Identifier: GPL-2.0-only */
3
4#include <stdio.h>
5#include <stdlib.h>
6#include <string.h>
7
8#include "elfparsing.h"
9#include "common.h"
10#include "cbfs.h"
11
12/*
13 * Short form: this is complicated, but we've tried making it simple
14 * and we keep hitting problems with our ELF parsing.
15 *
16 * The ELF parsing situation has always been a bit tricky. In fact,
17 * we (and most others) have been getting it wrong in small ways for
18 * years. Recently this has caused real trouble for the ARM V8 build.
19 * In this file we attempt to finally get it right for all variations
20 * of endian-ness and word size and target architectures and
21 * architectures we might get run on. Phew!. To do this we borrow a
22 * page from the FreeBSD NFS xdr model (see elf_ehdr and elf_phdr),
23 * the Plan 9 endianness functions (see xdr.c), and Go interfaces (see
24 * how we use buffer structs in this file). This ends up being a bit
25 * wordy at the lowest level, but greatly simplifies the elf parsing
26 * code and removes a common source of bugs, namely, forgetting to
27 * flip type endianness when referencing a struct member.
28 *
29 * ELF files can have four combinations of data layout: 32/64, and
30 * big/little endian. Further, to add to the fun, depending on the
31 * word size, the size of the ELF structs varies. The coreboot SELF
32 * format is simpler in theory: it's supposed to be always BE, and the
33 * various struct members allow room for growth: the entry point is
34 * always 64 bits, for example, so the size of a SELF struct is
35 * constant, regardless of target architecture word size. Hence, we
36 * need to do some transformation of the ELF files.
37 *
38 * A given architecture, realistically, only supports one of the four
39 * combinations at a time as the 'native' format. Hence, our code has
40 * been sprinkled with every variation of [nh]to[hn][sll] over the
41 * years. We've never quite gotten it all right, however, and a quick
42 * pass over this code revealed another bug. It's all worked because,
43 * until now, all the working platforms that had CBFS were 32 LE. Even then,
44 * however, bugs crept in: we recently realized that we're not
45 * transforming the entry point to big format when we store into the
46 * SELF image.
47 *
48 * The problem is essentially an XDR operation:
49 * we have something in a foreign format and need to transform it.
50 * It's most like XDR because:
51 * 1) the byte order can be wrong
52 * 2) the word size can be wrong
53 * 3) the size of elements in the stream depends on the value
54 * of other elements in the stream
55 * it's not like XDR because:
56 * 1) the byte order can be right
57 * 2) the word size can be right
58 * 3) the struct members are all on a natural alignment
59 *
60 * Hence, this new approach. To cover word size issues, we *always*
61 * transform the two structs we care about, the file header and
62 * program header, into a native struct in the 64 bit format:
63 *
64 * [32,little] -> [Elf64_Ehdr, Elf64_Phdr]
65 * [64,little] -> [Elf64_Ehdr, Elf64_Phdr]
66 * [32,big] -> [Elf64_Ehdr, Elf64_Phdr]
67 * [64,big] -> [Elf64_Ehdr, Elf64_Phdr]
68 * Then we just use those structs, and all the need for inline ntoh* goes away,
69 * as well as all the chances for error.
70 * This works because all the SELF structs have fields large enough for
71 * the largest ELF 64 struct members, and all the Elf64 struct members
72 * are at least large enough for all ELF 32 struct members.
73 * We end up with one function to do all our ELF parsing, and two functions
74 * to transform the headers. For the put case, we also have
75 * XDR functions, and hopefully we'll never again spend 5 years with the
76 * wrong endian-ness on an output value :-)
77 * This should work for all word sizes and endianness we hope to target.
78 * I *really* don't want to be here for 128 bit addresses.
79 *
80 * The parse functions are called with a pointer to an input buffer
81 * struct. One might ask: are there enough bytes in the input buffer?
82 * We know there need to be at *least* sizeof(Elf32_Ehdr) +
83 * sizeof(Elf32_Phdr) bytes. Realistically, there has to be some data
84 * too. If we start to worry, though we have not in the past, we
85 * might apply the simple test: the input buffer needs to be at least
86 * sizeof(Elf64_Ehdr) + sizeof(Elf64_Phdr) bytes because, even if it's
87 * ELF 32, there's got to be *some* data! This is not theoretically
88 * accurate but it is actually good enough in practice. It allows the
89 * header transformation code to ignore the possibility of underrun.
90 *
91 * We also must accommodate different ELF files, and hence formats,
92 * in the same cbfs invocation. We might load a 64-bit payload
93 * on a 32-bit machine; we might even have a mixed armv7/armv8
94 * SOC or even a system with an x86/ARM!
95 *
96 * A possibly problematic (though unlikely to be so) assumption
97 * is that we expect the BIOS to remain in the lowest 32 bits
98 * of the physical address space. Since ARMV8 has standardized
99 * on that, and x86_64 also has, this seems a safe assumption.
100 *
101 * To repeat, ELF structs are different sizes because ELF struct
102 * members are different sizes, depending on values in the ELF file
103 * header. For this we use the functions defined in xdr.c, which
104 * consume bytes, convert the endianness, and advance the data pointer
105 * in the buffer struct.
106 */
107
108
109static int iself(const void *input)
110{
111 const Elf32_Ehdr *ehdr = input;
112 return !memcmp(ehdr->e_ident, ELFMAG"\177ELF", 4);
113}
114
115/* Get the ident array, so we can figure out
116 * endian-ness, word size, and in future other useful
117 * parameters
118 */
119static void
120elf_eident(struct buffer *input, Elf64_Ehdr *ehdr)
121{
122 bgets(input, ehdr->e_ident, sizeof(ehdr->e_ident));
123}
124
125
126static int
127check_size(const struct buffer *b, size_t offset, size_t size, const char *desc)
128{
129 if (size == 0)
130 return 0;
131
132 if (offset >= buffer_size(b) || (offset + size) > buffer_size(b)) {
133 ERROR("The file is not large enough for the '%s'. "fprintf(stderr, "E: " "The file is not large enough for the '%s'. "
"%zu bytes @ offset %zu, input %zu bytes.\n", desc, size, offset
, buffer_size(b))
134 "%zu bytes @ offset %zu, input %zu bytes.\n",fprintf(stderr, "E: " "The file is not large enough for the '%s'. "
"%zu bytes @ offset %zu, input %zu bytes.\n", desc, size, offset
, buffer_size(b))
135 desc, size, offset, buffer_size(b))fprintf(stderr, "E: " "The file is not large enough for the '%s'. "
"%zu bytes @ offset %zu, input %zu bytes.\n", desc, size, offset
, buffer_size(b));
136 return -1;
137 }
138 return 0;
139}
140
141static void
142elf_ehdr(struct buffer *input, Elf64_Ehdr *ehdr, struct xdr *xdr, int bit64)
143{
144 ehdr->e_type = xdr->get16(input);
145 ehdr->e_machine = xdr->get16(input);
146 ehdr->e_version = xdr->get32(input);
147 if (bit64){
148 ehdr->e_entry = xdr->get64(input);
149 ehdr->e_phoff = xdr->get64(input);
150 ehdr->e_shoff = xdr->get64(input);
151 } else {
152 ehdr->e_entry = xdr->get32(input);
153 ehdr->e_phoff = xdr->get32(input);
154 ehdr->e_shoff = xdr->get32(input);
155 }
156 ehdr->e_flags = xdr->get32(input);
157 ehdr->e_ehsize = xdr->get16(input);
158 ehdr->e_phentsize = xdr->get16(input);
159 ehdr->e_phnum = xdr->get16(input);
160 ehdr->e_shentsize = xdr->get16(input);
161 ehdr->e_shnum = xdr->get16(input);
162 ehdr->e_shstrndx = xdr->get16(input);
163}
164
165static void
166elf_phdr(struct buffer *pinput, Elf64_Phdr *phdr,
167 int entsize, struct xdr *xdr, int bit64)
168{
169 /*
170 * The entsize need not be sizeof(*phdr).
171 * Hence, it is easier to keep a copy of the input,
172 * as the xdr functions may not advance the input
173 * pointer the full entsize; rather than get tricky
174 * we just advance it below.
175 */
176 struct buffer input;
177 buffer_clone(&input, pinput);
178 if (bit64){
179 phdr->p_type = xdr->get32(&input);
180 phdr->p_flags = xdr->get32(&input);
181 phdr->p_offset = xdr->get64(&input);
182 phdr->p_vaddr = xdr->get64(&input);
183 phdr->p_paddr = xdr->get64(&input);
184 phdr->p_filesz = xdr->get64(&input);
185 phdr->p_memsz = xdr->get64(&input);
186 phdr->p_align = xdr->get64(&input);
187 } else {
188 phdr->p_type = xdr->get32(&input);
189 phdr->p_offset = xdr->get32(&input);
190 phdr->p_vaddr = xdr->get32(&input);
191 phdr->p_paddr = xdr->get32(&input);
192 phdr->p_filesz = xdr->get32(&input);
193 phdr->p_memsz = xdr->get32(&input);
194 phdr->p_flags = xdr->get32(&input);
195 phdr->p_align = xdr->get32(&input);
196 }
197 buffer_seek(pinput, entsize);
198}
199
200static void
201elf_shdr(struct buffer *pinput, Elf64_Shdr *shdr,
202 int entsize, struct xdr *xdr, int bit64)
203{
204 /*
205 * The entsize need not be sizeof(*shdr).
206 * Hence, it is easier to keep a copy of the input,
207 * as the xdr functions may not advance the input
208 * pointer the full entsize; rather than get tricky
209 * we just advance it below.
210 */
211 struct buffer input = *pinput;
212 if (bit64){
213 shdr->sh_name = xdr->get32(&input);
214 shdr->sh_type = xdr->get32(&input);
215 shdr->sh_flags = xdr->get64(&input);
216 shdr->sh_addr = xdr->get64(&input);
217 shdr->sh_offset = xdr->get64(&input);
218 shdr->sh_size= xdr->get64(&input);
219 shdr->sh_link = xdr->get32(&input);
220 shdr->sh_info = xdr->get32(&input);
221 shdr->sh_addralign = xdr->get64(&input);
222 shdr->sh_entsize = xdr->get64(&input);
223 } else {
224 shdr->sh_name = xdr->get32(&input);
225 shdr->sh_type = xdr->get32(&input);
226 shdr->sh_flags = xdr->get32(&input);
227 shdr->sh_addr = xdr->get32(&input);
228 shdr->sh_offset = xdr->get32(&input);
229 shdr->sh_size = xdr->get32(&input);
230 shdr->sh_link = xdr->get32(&input);
231 shdr->sh_info = xdr->get32(&input);
232 shdr->sh_addralign = xdr->get32(&input);
233 shdr->sh_entsize = xdr->get32(&input);
234 }
235 buffer_seek(pinput, entsize);
236}
237
238static int
239phdr_read(const struct buffer *in, struct parsed_elf *pelf,
240 struct xdr *xdr, int bit64)
241{
242 struct buffer b;
243 Elf64_Phdr *phdr;
244 Elf64_Ehdr *ehdr;
245 int i;
246
247 ehdr = &pelf->ehdr;
248 /* cons up an input buffer for the headers.
249 * Note that the program headers can be anywhere,
250 * per the ELF spec, You'd be surprised how many ELF
251 * readers miss this little detail.
252 */
253 buffer_splice(&b, in, ehdr->e_phoff,
254 (uint32_t)ehdr->e_phentsize * ehdr->e_phnum);
255 if (check_size(in, ehdr->e_phoff, buffer_size(&b), "program headers"))
256 return -1;
257
258 /* gather up all the phdrs.
259 * We do them all at once because there is more
260 * than one loop over all the phdrs.
261 */
262 phdr = calloc(ehdr->e_phnum, sizeof(*phdr));
263 for (i = 0; i < ehdr->e_phnum; i++) {
264 DEBUG("Parsing segment %d\n", i)do { if (verbose > 1) fprintf(stderr, "DEBUG: " "Parsing segment %d\n"
, i); } while (0);
265 elf_phdr(&b, &phdr[i], ehdr->e_phentsize, xdr, bit64);
266
267 /* Ensure the contents are valid within the elf file. */
268 if (check_size(in, phdr[i].p_offset, phdr[i].p_filesz,
269 "segment contents")) {
270 free(phdr);
271 return -1;
272 }
273 }
274
275 pelf->phdr = phdr;
276
277 return 0;
278}
279
280static int
281shdr_read(const struct buffer *in, struct parsed_elf *pelf,
282 struct xdr *xdr, int bit64)
283{
284 struct buffer b;
285 Elf64_Shdr *shdr;
286 Elf64_Ehdr *ehdr;
287 int i;
288
289 ehdr = &pelf->ehdr;
290
291 /* cons up an input buffer for the section headers.
292 * Note that the section headers can be anywhere,
293 * per the ELF spec, You'd be surprised how many ELF
294 * readers miss this little detail.
295 */
296 buffer_splice(&b, in, ehdr->e_shoff,
297 (uint32_t)ehdr->e_shentsize * ehdr->e_shnum);
298 if (check_size(in, ehdr->e_shoff, buffer_size(&b), "section headers"))
299 return -1;
300
301 /* gather up all the shdrs. */
302 shdr = calloc(ehdr->e_shnum, sizeof(*shdr));
303 for (i = 0; i < ehdr->e_shnum; i++) {
304 DEBUG("Parsing section %d\n", i)do { if (verbose > 1) fprintf(stderr, "DEBUG: " "Parsing section %d\n"
, i); } while (0);
305 elf_shdr(&b, &shdr[i], ehdr->e_shentsize, xdr, bit64);
306 }
307
308 pelf->shdr = shdr;
309
310 return 0;
311}
312
313static int
314reloc_read(const struct buffer *in, struct parsed_elf *pelf,
315 struct xdr *xdr, int bit64)
316{
317 struct buffer b;
318 Elf64_Word i;
319 Elf64_Ehdr *ehdr;
320
321 ehdr = &pelf->ehdr;
322 pelf->relocs = calloc(ehdr->e_shnum, sizeof(Elf64_Rela *));
323
324 /* Allocate array for each section that contains relocation entries. */
325 for (i = 0; i < ehdr->e_shnum; i++) {
326 Elf64_Shdr *shdr;
327 Elf64_Rela *rela;
328 Elf64_Xword j;
329 Elf64_Xword nrelocs;
330 int is_rela;
331
332 shdr = &pelf->shdr[i];
333
334 /* Only process REL and RELA sections. */
335 if (shdr->sh_type != SHT_REL9 && shdr->sh_type != SHT_RELA4)
336 continue;
337
338 DEBUG("Checking relocation section %u\n", i)do { if (verbose > 1) fprintf(stderr, "DEBUG: " "Checking relocation section %u\n"
, i); } while (0);
339
340 /* Ensure the section that relocations apply is a valid. */
341 if (shdr->sh_info >= ehdr->e_shnum ||
342 shdr->sh_info == SHN_UNDEF0) {
343 ERROR("Relocations apply to an invalid section: %u\n",fprintf(stderr, "E: " "Relocations apply to an invalid section: %u\n"
, shdr[i].sh_info)
344 shdr[i].sh_info)fprintf(stderr, "E: " "Relocations apply to an invalid section: %u\n"
, shdr[i].sh_info);
345 return -1;
346 }
347
348 is_rela = shdr->sh_type == SHT_RELA4;
349
350 /* Determine the number relocations in this section. */
351 nrelocs = shdr->sh_size / shdr->sh_entsize;
352
353 pelf->relocs[i] = calloc(nrelocs, sizeof(Elf64_Rela));
354
355 buffer_splice(&b, in, shdr->sh_offset, shdr->sh_size);
356 if (check_size(in, shdr->sh_offset, buffer_size(&b),
357 "relocation section")) {
358 ERROR("Relocation section %u failed.\n", i)fprintf(stderr, "E: " "Relocation section %u failed.\n", i);
359 return -1;
360 }
361
362 rela = pelf->relocs[i];
363 for (j = 0; j < nrelocs; j++) {
364 if (bit64) {
365 rela->r_offset = xdr->get64(&b);
366 rela->r_info = xdr->get64(&b);
367 if (is_rela)
368 rela->r_addend = xdr->get64(&b);
369 } else {
370 uint32_t r_info;
371
372 rela->r_offset = xdr->get32(&b);
373 r_info = xdr->get32(&b);
374 rela->r_info = ELF64_R_INFO(ELF32_R_SYM(r_info),((((Elf64_Xword) (((r_info) >> 8))) << 32) + (((r_info
) & 0xff)))
375 ELF32_R_TYPE(r_info))((((Elf64_Xword) (((r_info) >> 8))) << 32) + (((r_info
) & 0xff)));
376 if (is_rela)
377 rela->r_addend = xdr->get32(&b);
378 }
379 rela++;
380 }
381 }
382
383 return 0;
384}
385
386static int strtab_read(const struct buffer *in, struct parsed_elf *pelf)
387{
388 Elf64_Ehdr *ehdr;
389 Elf64_Word i;
390
391 ehdr = &pelf->ehdr;
392
393 if (ehdr->e_shstrndx >= ehdr->e_shnum) {
394 ERROR("Section header string table index out of range: %d\n",fprintf(stderr, "E: " "Section header string table index out of range: %d\n"
, ehdr->e_shstrndx)
395 ehdr->e_shstrndx)fprintf(stderr, "E: " "Section header string table index out of range: %d\n"
, ehdr->e_shstrndx);
396 return -1;
397 }
398
399 /* For each section of type SHT_STRTAB create a symtab buffer. */
400 pelf->strtabs = calloc(ehdr->e_shnum, sizeof(struct buffer *));
401
402 for (i = 0; i < ehdr->e_shnum; i++) {
403 struct buffer *b;
404 Elf64_Shdr *shdr = &pelf->shdr[i];
405
406 if (shdr->sh_type != SHT_STRTAB3)
407 continue;
408
409 b = calloc(1, sizeof(*b));
410 buffer_splice(b, in, shdr->sh_offset, shdr->sh_size);
411 if (check_size(in, shdr->sh_offset, buffer_size(b), "strtab")) {
412 ERROR("STRTAB section not within bounds: %d\n", i)fprintf(stderr, "E: " "STRTAB section not within bounds: %d\n"
, i);
413 free(b);
414 return -1;
415 }
416 pelf->strtabs[i] = b;
417 }
418
419 return 0;
420}
421
422static int
423symtab_read(const struct buffer *in, struct parsed_elf *pelf,
424 struct xdr *xdr, int bit64)
425{
426 Elf64_Ehdr *ehdr;
427 Elf64_Shdr *shdr;
428 Elf64_Half shnum;
429 Elf64_Xword i;
430 Elf64_Xword nsyms;
431 Elf64_Sym *sym;
432 struct buffer b;
433
434 ehdr = &pelf->ehdr;
435
436 shdr = NULL((void*)0);
437 for (shnum = 0; shnum < ehdr->e_shnum; shnum++) {
438 if (pelf->shdr[shnum].sh_type != SHT_SYMTAB2)
439 continue;
440
441 if (shdr != NULL((void*)0)) {
442 ERROR("Multiple symbol sections found. %u and %u\n",fprintf(stderr, "E: " "Multiple symbol sections found. %u and %u\n"
, (unsigned int)(shdr - pelf->shdr), shnum)
443 (unsigned int)(shdr - pelf->shdr), shnum)fprintf(stderr, "E: " "Multiple symbol sections found. %u and %u\n"
, (unsigned int)(shdr - pelf->shdr), shnum);
444 return -1;
445 }
446
447 shdr = &pelf->shdr[shnum];
448 }
449
450 if (shdr == NULL((void*)0)) {
451 ERROR("No symbol table found.\n")fprintf(stderr, "E: " "No symbol table found.\n");
452 return -1;
453 }
454
455 buffer_splice(&b, in, shdr->sh_offset, shdr->sh_size);
456 if (check_size(in, shdr->sh_offset, buffer_size(&b), "symtab"))
457 return -1;
458
459 nsyms = shdr->sh_size / shdr->sh_entsize;
460
461 pelf->syms = calloc(nsyms, sizeof(Elf64_Sym));
462
463 for (i = 0; i < nsyms; i++) {
464 sym = &pelf->syms[i];
465
466 if (bit64) {
467 sym->st_name = xdr->get32(&b);
468 sym->st_info = xdr->get8(&b);
469 sym->st_other = xdr->get8(&b);
470 sym->st_shndx = xdr->get16(&b);
471 sym->st_value = xdr->get64(&b);
472 sym->st_size = xdr->get64(&b);
473 } else {
474 sym->st_name = xdr->get32(&b);
475 sym->st_value = xdr->get32(&b);
476 sym->st_size = xdr->get32(&b);
477 sym->st_info = xdr->get8(&b);
478 sym->st_other = xdr->get8(&b);
479 sym->st_shndx = xdr->get16(&b);
480 }
481 }
482
483 return 0;
484}
485
486int parse_elf(const struct buffer *pinput, struct parsed_elf *pelf, int flags)
487{
488 struct xdr *xdr = &xdr_le;
489 int bit64 = 0;
490 struct buffer input;
491 Elf64_Ehdr *ehdr;
492
493 /* Zero out the parsed elf structure. */
494 memset(pelf, 0, sizeof(*pelf));
495
496 if (!iself(buffer_get(pinput))) {
497 DEBUG("The stage file is not in ELF format!\n")do { if (verbose > 1) fprintf(stderr, "DEBUG: " "The stage file is not in ELF format!\n"
); } while (0);
498 return -1;
499 }
500
501 buffer_clone(&input, pinput);
502 ehdr = &pelf->ehdr;
503 elf_eident(&input, ehdr);
504 bit64 = ehdr->e_ident[EI_CLASS4] == ELFCLASS642;
505 /* Assume LE unless we are sure otherwise.
506 * We're not going to take on the task of
507 * fully validating the ELF file. That way
508 * lies madness.
509 */
510 if (ehdr->e_ident[EI_DATA5] == ELFDATA2MSB2)
511 xdr = &xdr_be;
512
513 elf_ehdr(&input, ehdr, xdr, bit64);
514
515 /* Relocation processing requires section header parsing. */
516 if (flags & ELF_PARSE_RELOC(1 << 2))
517 flags |= ELF_PARSE_SHDR(1 << 1);
518
519 /* String table processing requires section header parsing. */
520 if (flags & ELF_PARSE_STRTAB(1 << 3))
521 flags |= ELF_PARSE_SHDR(1 << 1);
522
523 /* Symbole table processing requires section header parsing. */
524 if (flags & ELF_PARSE_SYMTAB(1 << 4))
525 flags |= ELF_PARSE_SHDR(1 << 1);
526
527 if ((flags & ELF_PARSE_PHDR(1 << 0)) && phdr_read(pinput, pelf, xdr, bit64))
528 goto fail;
529
530 if ((flags & ELF_PARSE_SHDR(1 << 1)) && shdr_read(pinput, pelf, xdr, bit64))
531 goto fail;
532
533 if ((flags & ELF_PARSE_RELOC(1 << 2)) && reloc_read(pinput, pelf, xdr, bit64))
534 goto fail;
535
536 if ((flags & ELF_PARSE_STRTAB(1 << 3)) && strtab_read(pinput, pelf))
537 goto fail;
538
539 if ((flags & ELF_PARSE_SYMTAB(1 << 4)) && symtab_read(pinput, pelf, xdr, bit64))
540 goto fail;
541
542 return 0;
543
544fail:
545 parsed_elf_destroy(pelf);
546 return -1;
547}
548
549void parsed_elf_destroy(struct parsed_elf *pelf)
550{
551 Elf64_Half i;
552
553 free(pelf->phdr);
554 free(pelf->shdr);
555 if (pelf->relocs != NULL((void*)0)) {
556 for (i = 0; i < pelf->ehdr.e_shnum; i++)
557 free(pelf->relocs[i]);
558 }
559 free(pelf->relocs);
560
561 if (pelf->strtabs != NULL((void*)0)) {
562 for (i = 0; i < pelf->ehdr.e_shnum; i++)
563 free(pelf->strtabs[i]);
564 }
565 free(pelf->strtabs);
566 free(pelf->syms);
567}
568
569/* Get the headers from the buffer.
570 * Return -1 in the event of an error.
571 * The section headers are optional; if NULL
572 * is passed in for pshdr they won't be parsed.
573 * We don't (yet) make payload parsing optional
574 * because we've never seen a use case.
575 */
576int
577elf_headers(const struct buffer *pinput,
578 Elf64_Ehdr *ehdr,
579 Elf64_Phdr **pphdr,
580 Elf64_Shdr **pshdr)
581{
582 struct parsed_elf pelf;
583 int flags;
584
585 flags = ELF_PARSE_PHDR(1 << 0);
586
587 if (pshdr != NULL((void*)0))
588 flags |= ELF_PARSE_SHDR(1 << 1);
589
590 if (parse_elf(pinput, &pelf, flags))
591 return -1;
592
593 /* Copy out the parsed elf header. */
594 memcpy(ehdr, &pelf.ehdr, sizeof(*ehdr));
595
596 *pphdr = calloc(ehdr->e_phnum, sizeof(Elf64_Phdr));
597 memcpy(*pphdr, pelf.phdr, ehdr->e_phnum * sizeof(Elf64_Phdr));
598
599 if (pshdr != NULL((void*)0)) {
600 *pshdr = calloc(ehdr->e_shnum, sizeof(Elf64_Shdr));
601 memcpy(*pshdr, pelf.shdr, ehdr->e_shnum * sizeof(Elf64_Shdr));
602 }
603
604 parsed_elf_destroy(&pelf);
605
606 return 0;
607}
608
609/* ELF Writing Support
610 *
611 * The ELF file is written according to the following layout:
612 * +------------------+
613 * | ELF Header |
614 * +------------------+
615 * | Section Headers |
616 * +------------------+
617 * | Program Headers |
618 * +------------------+
619 * | String table |
620 * +------------------+ <- 4KiB Aligned
621 * | Code/Data |
622 * +------------------+
623 */
624
625void elf_init_eheader(Elf64_Ehdr *ehdr, int machine, int nbits, int endian)
626{
627 memset(ehdr, 0, sizeof(*ehdr));
628 ehdr->e_ident[EI_MAG00] = ELFMAG00x7f;
629 ehdr->e_ident[EI_MAG11] = ELFMAG1'E';
630 ehdr->e_ident[EI_MAG22] = ELFMAG2'L';
631 ehdr->e_ident[EI_MAG33] = ELFMAG3'F';
632 ehdr->e_ident[EI_CLASS4] = nbits;
633 ehdr->e_ident[EI_DATA5] = endian;
634 ehdr->e_ident[EI_VERSION6] = EV_CURRENT1;
635 ehdr->e_type = ET_EXEC2;
636 ehdr->e_machine = machine;
637 ehdr->e_version = EV_CURRENT1;
638 if (nbits == ELFCLASS642) {
639 ehdr->e_ehsize = sizeof(Elf64_Ehdr);
640 ehdr->e_phentsize = sizeof(Elf64_Phdr);
641 ehdr->e_shentsize = sizeof(Elf64_Shdr);
642 } else {
643 ehdr->e_ehsize = sizeof(Elf32_Ehdr);
644 ehdr->e_phentsize = sizeof(Elf32_Phdr);
645 ehdr->e_shentsize = sizeof(Elf32_Shdr);
646 }
647}
648
649/* Arbitrary maximum number of sections. */
650#define MAX_SECTIONS16 16
651struct elf_writer_section {
652 Elf64_Shdr shdr;
653 struct buffer content;
654 const char *name;
655};
656
657struct elf_writer_string_table {
658 size_t next_offset;
659 size_t max_size;
660 char *buffer;
661};
662
663struct elf_writer_sym_table {
664 size_t max_entries;
665 size_t num_entries;
666 Elf64_Sym *syms;
667};
668
669#define MAX_REL_NAME32 32
670struct elf_writer_rel {
671 size_t num_entries;
672 size_t max_entries;
673 Elf64_Rel *rels;
674 struct elf_writer_section *sec;
675 char name[MAX_REL_NAME32];
676};
677
678struct elf_writer
679{
680 Elf64_Ehdr ehdr;
681 struct xdr *xdr;
682 size_t num_secs;
683 struct elf_writer_section sections[MAX_SECTIONS16];
684 struct elf_writer_rel rel_sections[MAX_SECTIONS16];
685 Elf64_Phdr *phdrs;
686 struct elf_writer_section *shstrtab_sec;
687 struct elf_writer_section *strtab_sec;
688 struct elf_writer_section *symtab_sec;
689 struct elf_writer_string_table strtab;
690 struct elf_writer_sym_table symtab;
691 int bit64;
692};
693
694static size_t section_index(struct elf_writer *ew,
695 struct elf_writer_section *sec)
696{
697 return sec - &ew->sections[0];
698}
699
700static struct elf_writer_section *last_section(struct elf_writer *ew)
701{
702 return &ew->sections[ew->num_secs - 1];
703}
704
705static void strtab_init(struct elf_writer *ew, size_t size)
706{
707 struct buffer b;
708 Elf64_Shdr shdr;
709
710 /* Start adding strings after the initial NUL entry. */
711 ew->strtab.next_offset = 1;
712 ew->strtab.max_size = size;
713 ew->strtab.buffer = calloc(1, ew->strtab.max_size);
714
715 buffer_init(&b, NULL((void*)0), ew->strtab.buffer, ew->strtab.max_size);
716 memset(&shdr, 0, sizeof(shdr));
717 shdr.sh_type = SHT_STRTAB3;
718 shdr.sh_addralign = 1;
719 shdr.sh_size = ew->strtab.max_size;
720 elf_writer_add_section(ew, &shdr, &b, ".strtab");
721 ew->strtab_sec = last_section(ew);
722}
723
724static void symtab_init(struct elf_writer *ew, size_t max_entries)
725{
726 struct buffer b;
727 Elf64_Shdr shdr;
728
729 memset(&shdr, 0, sizeof(shdr));
730 shdr.sh_type = SHT_SYMTAB2;
731
732 if (ew->bit64) {
733 shdr.sh_entsize = sizeof(Elf64_Sym);
734 shdr.sh_addralign = sizeof(Elf64_Addr);
735 } else {
736 shdr.sh_entsize = sizeof(Elf32_Sym);
737 shdr.sh_addralign = sizeof(Elf32_Addr);
738 }
739
740 shdr.sh_size = shdr.sh_entsize * max_entries;
741
742 ew->symtab.syms = calloc(max_entries, sizeof(Elf64_Sym));
743 ew->symtab.num_entries = 1;
744 ew->symtab.max_entries = max_entries;
745
746 buffer_init(&b, NULL((void*)0), ew->symtab.syms, shdr.sh_size);
747
748 elf_writer_add_section(ew, &shdr, &b, ".symtab");
749 ew->symtab_sec = last_section(ew);
750}
751
752struct elf_writer *elf_writer_init(const Elf64_Ehdr *ehdr)
753{
754 struct elf_writer *ew;
755 Elf64_Shdr shdr;
756 struct buffer empty_buffer;
757
758 if (!iself(ehdr))
759 return NULL((void*)0);
760
761 ew = calloc(1, sizeof(*ew));
762
763 memcpy(&ew->ehdr, ehdr, sizeof(ew->ehdr));
764
765 ew->bit64 = ew->ehdr.e_ident[EI_CLASS4] == ELFCLASS642;
766
767 /* Set the endinan ops. */
768 if (ew->ehdr.e_ident[EI_DATA5] == ELFDATA2MSB2)
769 ew->xdr = &xdr_be;
770 else
771 ew->xdr = &xdr_le;
772
773 /* Reset count and offsets */
774 ew->ehdr.e_phoff = 0;
775 ew->ehdr.e_shoff = 0;
776 ew->ehdr.e_shnum = 0;
777 ew->ehdr.e_phnum = 0;
778
779 memset(&empty_buffer, 0, sizeof(empty_buffer));
780 memset(&shdr, 0, sizeof(shdr));
781
782 /* Add SHT_NULL section header. */
783 shdr.sh_type = SHT_NULL0;
784 elf_writer_add_section(ew, &shdr, &empty_buffer, NULL((void*)0));
785
786 /* Add section header string table and maintain reference to it. */
787 shdr.sh_type = SHT_STRTAB3;
788 elf_writer_add_section(ew, &shdr, &empty_buffer, ".shstrtab");
789 ew->shstrtab_sec = last_section(ew);
790 ew->ehdr.e_shstrndx = section_index(ew, ew->shstrtab_sec);
791
792 /* Add a small string table and symbol table. */
793 strtab_init(ew, 4096);
794 symtab_init(ew, 100);
795
796 return ew;
797}
798
799/*
800 * Clean up any internal state represented by ew. Aftewards the elf_writer
801 * is invalid.
802 * It is safe to call elf_writer_destroy with ew as NULL. It returns without
803 * performing any action.
804 */
805void elf_writer_destroy(struct elf_writer *ew)
806{
807 int i;
808 if (ew == NULL((void*)0))
809 return;
810 if (ew->phdrs != NULL((void*)0))
811 free(ew->phdrs);
812 free(ew->strtab.buffer);
813 free(ew->symtab.syms);
814 for (i = 0; i < MAX_SECTIONS16; i++)
815 free(ew->rel_sections[i].rels);
816 free(ew);
817}
818
819/*
820 * Add a section to the ELF file. Section type, flags, and memsize are
821 * maintained from the passed in Elf64_Shdr. The buffer represents the
822 * content of the section while the name is the name of section itself.
823 * Returns < 0 on error, 0 on success.
824 */
825int elf_writer_add_section(struct elf_writer *ew, const Elf64_Shdr *shdr,
826 struct buffer *contents, const char *name)
827{
828 struct elf_writer_section *newsh;
829
830 if (ew->num_secs == MAX_SECTIONS16)
831 return -1;
832
833 newsh = &ew->sections[ew->num_secs];
834 ew->num_secs++;
835
836 memcpy(&newsh->shdr, shdr, sizeof(newsh->shdr));
837 newsh->shdr.sh_offset = 0;
838
839 newsh->name = name;
840 if (contents != NULL((void*)0))
841 buffer_clone(&newsh->content, contents);
842
843 return 0;
844}
845
846static void ehdr_write(struct elf_writer *ew, struct buffer *m)
847{
848 int i;
849
850 for (i = 0; i < EI_NIDENT(16); i++)
851 ew->xdr->put8(m, ew->ehdr.e_ident[i]);
852 ew->xdr->put16(m, ew->ehdr.e_type);
853 ew->xdr->put16(m, ew->ehdr.e_machine);
854 ew->xdr->put32(m, ew->ehdr.e_version);
855 if (ew->bit64) {
856 ew->xdr->put64(m, ew->ehdr.e_entry);
857 ew->xdr->put64(m, ew->ehdr.e_phoff);
858 ew->xdr->put64(m, ew->ehdr.e_shoff);
859 } else {
860 ew->xdr->put32(m, ew->ehdr.e_entry);
861 ew->xdr->put32(m, ew->ehdr.e_phoff);
862 ew->xdr->put32(m, ew->ehdr.e_shoff);
863 }
864 ew->xdr->put32(m, ew->ehdr.e_flags);
865 ew->xdr->put16(m, ew->ehdr.e_ehsize);
866 ew->xdr->put16(m, ew->ehdr.e_phentsize);
867 ew->xdr->put16(m, ew->ehdr.e_phnum);
868 ew->xdr->put16(m, ew->ehdr.e_shentsize);
869 ew->xdr->put16(m, ew->ehdr.e_shnum);
870 ew->xdr->put16(m, ew->ehdr.e_shstrndx);
871}
872
873static void shdr_write(struct elf_writer *ew, size_t n, struct buffer *m)
874{
875 struct xdr *xdr = ew->xdr;
876 int bit64 = ew->bit64;
877 struct elf_writer_section *sec = &ew->sections[n];
878 Elf64_Shdr *shdr = &sec->shdr;
879
880 xdr->put32(m, shdr->sh_name);
881 xdr->put32(m, shdr->sh_type);
882 if (bit64) {
883 xdr->put64(m, shdr->sh_flags);
884 xdr->put64(m, shdr->sh_addr);
885 xdr->put64(m, shdr->sh_offset);
886 xdr->put64(m, shdr->sh_size);
887 xdr->put32(m, shdr->sh_link);
888 xdr->put32(m, shdr->sh_info);
889 xdr->put64(m, shdr->sh_addralign);
890 xdr->put64(m, shdr->sh_entsize);
891 } else {
892 xdr->put32(m, shdr->sh_flags);
893 xdr->put32(m, shdr->sh_addr);
894 xdr->put32(m, shdr->sh_offset);
895 xdr->put32(m, shdr->sh_size);
896 xdr->put32(m, shdr->sh_link);
897 xdr->put32(m, shdr->sh_info);
898 xdr->put32(m, shdr->sh_addralign);
899 xdr->put32(m, shdr->sh_entsize);
900 }
901}
902
903static void
904phdr_write(struct elf_writer *ew, struct buffer *m, Elf64_Phdr *phdr)
905{
906 if (ew->bit64) {
907 ew->xdr->put32(m, phdr->p_type);
908 ew->xdr->put32(m, phdr->p_flags);
909 ew->xdr->put64(m, phdr->p_offset);
910 ew->xdr->put64(m, phdr->p_vaddr);
911 ew->xdr->put64(m, phdr->p_paddr);
912 ew->xdr->put64(m, phdr->p_filesz);
913 ew->xdr->put64(m, phdr->p_memsz);
914 ew->xdr->put64(m, phdr->p_align);
915 } else {
916 ew->xdr->put32(m, phdr->p_type);
917 ew->xdr->put32(m, phdr->p_offset);
918 ew->xdr->put32(m, phdr->p_vaddr);
919 ew->xdr->put32(m, phdr->p_paddr);
920 ew->xdr->put32(m, phdr->p_filesz);
921 ew->xdr->put32(m, phdr->p_memsz);
922 ew->xdr->put32(m, phdr->p_flags);
923 ew->xdr->put32(m, phdr->p_align);
924 }
925
926}
927
928static int section_consecutive(struct elf_writer *ew, Elf64_Half secidx)
929{
930 Elf64_Half i;
931 struct elf_writer_section *prev_alloc = NULL((void*)0);
932
933 if (secidx == 0)
934 return 0;
935
936 for (i = 0; i < secidx; i++) {
937 if (ew->sections[i].shdr.sh_flags & SHF_ALLOC(1 << 1))
938 prev_alloc = &ew->sections[i];
939 }
940
941 if (prev_alloc == NULL((void*)0))
942 return 0;
943
944 if (prev_alloc->shdr.sh_addr + prev_alloc->shdr.sh_size ==
945 ew->sections[secidx].shdr.sh_addr)
946 return 1;
947
948 return 0;
949}
950
951static void write_phdrs(struct elf_writer *ew, struct buffer *phdrs)
952{
953 Elf64_Half i;
954 Elf64_Phdr phdr;
955 size_t num_written = 0;
956 size_t num_needs_write = 0;
957
958 for (i = 0; i < ew->num_secs; i++) {
20
←
Loop condition is true. Entering loop body
→
959 struct elf_writer_section *sec = &ew->sections[i];
960
961 if (!(sec->shdr.sh_flags & SHF_ALLOC(1 << 1)))
21
←
Assuming the condition is false
→
22
←
Taking false branch
→
962 continue;
963
964 if (!section_consecutive(ew, i)) {
23
←
Assuming the condition is false
→
24
←
Taking false branch
→
965 /* Write out previously set phdr. */
966 if (num_needs_write != num_written) {
967 phdr_write(ew, phdrs, &phdr);
968 num_written++;
969 }
970 phdr.p_type = PT_LOAD1;
971 phdr.p_offset = sec->shdr.sh_offset;
972 phdr.p_vaddr = sec->shdr.sh_addr;
973 phdr.p_paddr = sec->shdr.sh_addr;
974 phdr.p_filesz = buffer_size(&sec->content);
975 phdr.p_memsz = sec->shdr.sh_size;
976 phdr.p_flags = 0;
977 if (sec->shdr.sh_flags & SHF_EXECINSTR(1 << 2))
978 phdr.p_flags |= PF_X(1 << 0) | PF_R(1 << 2);
979 if (sec->shdr.sh_flags & SHF_WRITE(1 << 0))
980 phdr.p_flags |= PF_W(1 << 1);
981 phdr.p_align = sec->shdr.sh_addralign;
982 num_needs_write++;
983
984 } else {
985 /* Accumulate file size and memsize. The assumption
986 * is that each section is either NOBITS or full
987 * (sh_size == file size). This is standard in that
988 * an ELF section doesn't have a file size component. */
989 if (sec->shdr.sh_flags & SHF_EXECINSTR(1 << 2))
25
←
Assuming the condition is true
→
26
←
Taking true branch
→
990 phdr.p_flags |= PF_X(1 << 0) | PF_R(1 << 2);
27
←
The left expression of the compound assignment is an uninitialized value. The computed value will also be garbage
991 if (sec->shdr.sh_flags & SHF_WRITE(1 << 0))
992 phdr.p_flags |= PF_W(1 << 1);
993 phdr.p_filesz += buffer_size(&sec->content);
994 phdr.p_memsz += sec->shdr.sh_size;
995 }
996 }
997
998 /* Write out the last phdr. */
999 if (num_needs_write != num_written) {
1000 phdr_write(ew, phdrs, &phdr);
1001 num_written++;
1002 }
1003 assert(num_written == ew->ehdr.e_phnum)((num_written == ew->ehdr.e_phnum) ? (void) (0) : __assert_fail
("num_written == ew->ehdr.e_phnum", "/home/coreboot/node-root/workspace/coreboot_scanbuild/util/cbfstool/elfheaders.c"
, 1003, __extension__ __PRETTY_FUNCTION__));
1004}
1005
1006static void fixup_symbol_table(struct elf_writer *ew)
1007{
1008 struct elf_writer_section *sec = ew->symtab_sec;
1009
1010 /* If there is only the NULL section, mark section as inactive. */
1011 if (ew->symtab.num_entries == 1) {
1012 sec->shdr.sh_type = SHT_NULL0;
1013 sec->shdr.sh_size = 0;
1014 } else {
1015 size_t i;
1016 struct buffer wr;
1017
1018 buffer_clone(&wr, &sec->content);
1019 /* To appease xdr. */
1020 buffer_set_size(&wr, 0);
1021 for (i = 0; i < ew->symtab.num_entries; i++) {
1022 /* Create local copy as were over-writing backing
1023 * store of the symbol. */
1024 Elf64_Sym sym = ew->symtab.syms[i];
1025 if (ew->bit64) {
1026 ew->xdr->put32(&wr, sym.st_name);
1027 ew->xdr->put8(&wr, sym.st_info);
1028 ew->xdr->put8(&wr, sym.st_other);
1029 ew->xdr->put16(&wr, sym.st_shndx);
1030 ew->xdr->put64(&wr, sym.st_value);
1031 ew->xdr->put64(&wr, sym.st_size);
1032 } else {
1033 ew->xdr->put32(&wr, sym.st_name);
1034 ew->xdr->put32(&wr, sym.st_value);
1035 ew->xdr->put32(&wr, sym.st_size);
1036 ew->xdr->put8(&wr, sym.st_info);
1037 ew->xdr->put8(&wr, sym.st_other);
1038 ew->xdr->put16(&wr, sym.st_shndx);
1039 }
1040 }
1041
1042 /* Update section size. */
1043 sec->shdr.sh_size = sec->shdr.sh_entsize;
1044 sec->shdr.sh_size *= ew->symtab.num_entries;
1045
1046 /* Fix up sh_link to point to string table. */
1047 sec->shdr.sh_link = section_index(ew, ew->strtab_sec);
1048 /* sh_info is supposed to be 1 greater than symbol table
1049 * index of last local binding. Just use max symbols. */
1050 sec->shdr.sh_info = ew->symtab.num_entries;
1051 }
1052
1053 buffer_set_size(&sec->content, sec->shdr.sh_size);
1054}
1055
1056static void fixup_relocations(struct elf_writer *ew)
1057{
1058 int i;
1059 Elf64_Xword type;
1060
1061 switch (ew->ehdr.e_machine) {
1062 case EM_3863:
1063 type = R_386_321;
1064 break;
1065 case EM_X86_6462:
1066 type = R_AMD64_641;
1067 break;
1068 case EM_ARM40:
1069 type = R_ARM_ABS322;
1070 break;
1071 case EM_AARCH64183:
1072 type = R_AARCH64_ABS64257;
1073 break;
1074 case EM_MIPS8:
1075 type = R_MIPS_322;
1076 break;
1077 case EM_RISCV0xF3:
1078 type = R_RISCV_322;
1079 break;
1080 case EM_PPC6421:
1081 type = R_PPC64_ADDR321;
1082 break;
1083 default:
1084 ERROR("Unable to handle relocations for e_machine %x\n",fprintf(stderr, "E: " "Unable to handle relocations for e_machine %x\n"
, ew->ehdr.e_machine)
1085 ew->ehdr.e_machine)fprintf(stderr, "E: " "Unable to handle relocations for e_machine %x\n"
, ew->ehdr.e_machine);
1086 return;
1087 }
1088
1089 for (i = 0; i < MAX_SECTIONS16; i++) {
1090 struct elf_writer_rel *rel_sec = &ew->rel_sections[i];
1091 struct elf_writer_section *sec = rel_sec->sec;
1092 struct buffer writer;
1093 size_t j;
1094
1095 if (sec == NULL((void*)0))
1096 continue;
1097
1098 /* Update section header size as well as content size. */
1099 buffer_init(&sec->content, sec->content.name, rel_sec->rels,
1100 rel_sec->num_entries * sec->shdr.sh_entsize);
1101 sec->shdr.sh_size = buffer_size(&sec->content);
1102 buffer_clone(&writer, &sec->content);
1103 /* To make xdr happy. */
1104 buffer_set_size(&writer, 0);
1105
1106 for (j = 0; j < ew->rel_sections[i].num_entries; j++) {
1107 /* Make copy as we're overwriting backing store. */
1108 Elf64_Rel rel = rel_sec->rels[j];
1109 rel.r_info = ELF64_R_INFO(ELF64_R_SYM(rel.r_info),((((Elf64_Xword) (((rel.r_info) >> 32))) << 32) +
(((type) & 0xffffffff)))
1110 ELF64_R_TYPE(type))((((Elf64_Xword) (((rel.r_info) >> 32))) << 32) +
(((type) & 0xffffffff)));
1111
1112 if (ew->bit64) {
1113 ew->xdr->put64(&writer, rel.r_offset);
1114 ew->xdr->put64(&writer, rel.r_info);
1115 } else {
1116 Elf32_Rel rel32;
1117 rel32.r_offset = rel.r_offset;
1118 rel32.r_info =
1119 ELF32_R_INFO(ELF64_R_SYM(rel.r_info),(((((rel.r_info) >> 32)) << 8) + ((((rel.r_info) &
0xffffffff)) & 0xff))
1120 ELF64_R_TYPE(rel.r_info))(((((rel.r_info) >> 32)) << 8) + ((((rel.r_info) &
0xffffffff)) & 0xff));
1121 ew->xdr->put32(&writer, rel32.r_offset);
1122 ew->xdr->put32(&writer, rel32.r_info);
1123 }
1124 }
1125 }
1126}
1127
1128/*
1129 * Serialize the ELF file to the output buffer. Return < 0 on error,
1130 * 0 on success.
1131 */
1132int elf_writer_serialize(struct elf_writer *ew, struct buffer *out)
1133{
1134 Elf64_Half i;
1135 Elf64_Xword metadata_size;
1136 Elf64_Xword program_size;
1137 Elf64_Off shstroffset;
1138 size_t shstrlen;
1139 struct buffer metadata;
1140 struct buffer phdrs;
1141 struct buffer data;
1142 struct buffer *strtab;
1143
1144 INFO("Writing %zu sections.\n", ew->num_secs)do { if (verbose > 0) fprintf(stderr, "INFO: " "Writing %zu sections.\n"
, ew->num_secs); } while (0);
1
Assuming 'verbose' is <= 0
→
2
←
Taking false branch
→
3
←
Loop condition is false. Exiting loop
→
1145
1146 /* Perform any necessary work for special sections. */
1147 fixup_symbol_table(ew);
1148 fixup_relocations(ew);
1149
1150 /* Determine size of sections to be written. */
1151 program_size = 0;
1152 /* Start with 1 byte for first byte of section header string table. */
1153 shstrlen = 1;
1154 for (i = 0; i < ew->num_secs; i++) {
4
←
Assuming 'i' is >= field 'num_secs'
→
5
←
Loop condition is false. Execution continues on line 1170
→
1155 struct elf_writer_section *sec = &ew->sections[i];
1156
1157 if (sec->shdr.sh_flags & SHF_ALLOC(1 << 1)) {
1158 if (!section_consecutive(ew, i))
1159 ew->ehdr.e_phnum++;
1160 }
1161
1162 program_size += buffer_size(&sec->content);
1163
1164 /* Keep track of the length sections' names. */
1165 if (sec->name != NULL((void*)0)) {
1166 sec->shdr.sh_name = shstrlen;
1167 shstrlen += strlen(sec->name) + 1;
1168 }
1169 }
1170 ew->ehdr.e_shnum = ew->num_secs;
1171 metadata_size = 0;
1172 metadata_size += ew->ehdr.e_ehsize;
1173 metadata_size += (Elf64_Xword)ew->ehdr.e_shnum * ew->ehdr.e_shentsize;
1174 metadata_size += (Elf64_Xword)ew->ehdr.e_phnum * ew->ehdr.e_phentsize;
1175 shstroffset = metadata_size;
1176 /* Align up section header string size and metadata size to 4KiB */
1177 metadata_size = ALIGN_UP(metadata_size + shstrlen, 4096)((((metadata_size + shstrlen))+((__typeof__((metadata_size + shstrlen
)))((4096))-1UL))&~((__typeof__((metadata_size + shstrlen
)))((4096))-1UL));
1178
1179 if (buffer_create(out, metadata_size + program_size, "elfout")) {
6
←
Assuming the condition is false
→
7
←
Taking false branch
→
1180 ERROR("Could not create output buffer for ELF.\n")fprintf(stderr, "E: " "Could not create output buffer for ELF.\n"
);
1181 return -1;
1182 }
1183
1184 INFO("Created %zu output buffer for ELF file.\n", buffer_size(out))do { if (verbose > 0) fprintf(stderr, "INFO: " "Created %zu output buffer for ELF file.\n"
, buffer_size(out)); } while (0);
8
←
Assuming 'verbose' is <= 0
→
9
←
Taking false branch
→
10
←
Loop condition is false. Exiting loop
→
1185
1186 /*
1187 * Write out ELF header. Section headers come right after ELF header
1188 * followed by the program headers. Buffers need to be created first
1189 * to do the writing.
1190 */
1191 ew->ehdr.e_shoff = ew->ehdr.e_ehsize;
1192 ew->ehdr.e_phoff = ew->ehdr.e_shoff +
1193 (Elf64_Off)ew->ehdr.e_shnum * ew->ehdr.e_shentsize;
1194
1195 buffer_splice(&metadata, out, 0, metadata_size);
1196 buffer_splice(&phdrs, out, ew->ehdr.e_phoff,
1197 (uint32_t)ew->ehdr.e_phnum * ew->ehdr.e_phentsize);
1198 buffer_splice(&data, out, metadata_size, program_size);
1199 /* Set up the section header string table contents. */
1200 strtab = &ew->shstrtab_sec->content;
1201 buffer_splice(strtab, out, shstroffset, shstrlen);
1202 ew->shstrtab_sec->shdr.sh_size = shstrlen;
1203
1204 /* Reset current locations. */
1205 buffer_set_size(&metadata, 0);
1206 buffer_set_size(&data, 0);
1207 buffer_set_size(&phdrs, 0);
1208 buffer_set_size(strtab, 0);
1209
1210 /* ELF Header */
1211 ehdr_write(ew, &metadata);
1212
1213 /* Write out section headers, section strings, section content, and
1214 * program headers. */
1215 ew->xdr->put8(strtab, 0);
1216 for (i = 0; i < ew->num_secs; i++) {
11
←
Assuming 'i' is < field 'num_secs'
→
12
←
Loop condition is true. Entering loop body
→
17
←
Assuming 'i' is >= field 'num_secs'
→
18
←
Loop condition is false. Execution continues on line 1239
→
1217 struct elf_writer_section *sec = &ew->sections[i];
1218
1219 /* Update section offsets. Be sure to not update SHN_UNDEF. */
1220 if (sec == ew->shstrtab_sec)
13
←
Assuming 'sec' is equal to field 'shstrtab_sec'
→
14
←
Taking true branch
→
1221 sec->shdr.sh_offset = shstroffset;
1222 else if (i != SHN_UNDEF0)
1223 sec->shdr.sh_offset = buffer_size(&data) +
1224 metadata_size;
1225
1226 shdr_write(ew, i, &metadata);
1227
1228 /* Add section name to string table. */
1229 if (sec->name != NULL((void*)0))
15
←
Assuming field 'name' is not equal to NULL
→
16
←
Taking true branch
→
1230 bputs(strtab, sec->name, strlen(sec->name) + 1);
1231
1232 /* Output section data for all sections but SHN_UNDEF and
1233 * section header string table. */
1234 if (i
16.1
'i' is equal to SHN_UNDEF
 != SHN_UNDEF0 && sec != ew->shstrtab_sec)
1235 bputs(&data, buffer_get(&sec->content),
1236 buffer_size(&sec->content));
1237 }
1238
1239 write_phdrs(ew, &phdrs);
19
←
Calling 'write_phdrs'
→
1240
1241 return 0;
1242}
1243
1244/* Add a string to the string table returning index on success, < 0 on error. */
1245static int elf_writer_add_string(struct elf_writer *ew, const char *new)
1246{
1247 size_t current_offset;
1248 size_t new_len;
1249
1250 for (current_offset = 0; current_offset < ew->strtab.next_offset; ) {
1251 const char *str = ew->strtab.buffer + current_offset;
1252 size_t len = strlen(str) + 1;
1253
1254 if (!strcmp(str, new))
1255 return current_offset;
1256 current_offset += len;
1257 }
1258
1259 new_len = strlen(new) + 1;
1260
1261 if (current_offset + new_len > ew->strtab.max_size) {
1262 ERROR("No space for string in .strtab.\n")fprintf(stderr, "E: " "No space for string in .strtab.\n");
1263 return -1;
1264 }
1265
1266 memcpy(ew->strtab.buffer + current_offset, new, new_len);
1267 ew->strtab.next_offset = current_offset + new_len;
1268
1269 return current_offset;
1270}
1271
1272static int elf_writer_section_index(struct elf_writer *ew, const char *name)
1273{
1274 size_t i;
1275
1276 for (i = 0; i < ew->num_secs; i++) {
1277 if (ew->sections[i].name == NULL((void*)0))
1278 continue;
1279 if (!strcmp(ew->sections[i].name, name))
1280 return i;
1281 }
1282
1283 ERROR("ELF Section not found: %s\n", name)fprintf(stderr, "E: " "ELF Section not found: %s\n", name);
1284
1285 return -1;
1286}
1287
1288int elf_writer_add_symbol(struct elf_writer *ew, const char *name,
1289 const char *section_name,
1290 Elf64_Addr value, Elf64_Word size,
1291 int binding, int type)
1292{
1293 int i;
1294 Elf64_Sym sym = {
1295 .st_value = value,
1296 .st_size = size,
1297 .st_info = ELF64_ST_INFO(binding, type)((((binding)) << 4) + (((type)) & 0xf)),
1298 };
1299
1300 if (ew->symtab.max_entries == ew->symtab.num_entries) {
1301 ERROR("No more symbol entries left.\n")fprintf(stderr, "E: " "No more symbol entries left.\n");
1302 return -1;
1303 }
1304
1305 i = elf_writer_add_string(ew, name);
1306 if (i < 0)
1307 return -1;
1308 sym.st_name = i;
1309
1310 i = elf_writer_section_index(ew, section_name);
1311 if (i < 0)
1312 return -1;
1313 sym.st_shndx = i;
1314
1315 ew->symtab.syms[ew->symtab.num_entries++] = sym;
1316
1317 return 0;
1318}
1319
1320static int elf_sym_index(struct elf_writer *ew, const char *sym)
1321{
1322 int j;
1323 size_t i;
1324 Elf64_Word st_name;
1325
1326 /* Determine index of symbol in the string table. */
1327 j = elf_writer_add_string(ew, sym);
1328 if (j < 0)
1329 return -1;
1330
1331 st_name = j;
1332
1333 for (i = 0; i < ew->symtab.num_entries; i++)
1334 if (ew->symtab.syms[i].st_name == st_name)
1335 return i;
1336
1337 return -1;
1338}
1339
1340static struct elf_writer_rel *rel_section(struct elf_writer *ew,
1341 const Elf64_Rel *r)
1342{
1343 Elf64_Sym *sym;
1344 struct elf_writer_rel *rel;
1345 Elf64_Shdr shdr;
1346 struct buffer b;
1347
1348 sym = &ew->symtab.syms[ELF64_R_SYM(r->r_info)((r->r_info) >> 32)];
1349
1350 /* Determine if section has been initialized yet. */
1351 rel = &ew->rel_sections[sym->st_shndx];
1352 if (rel->sec != NULL((void*)0))
1353 return rel;
1354
1355 memset(&shdr, 0, sizeof(shdr));
1356 shdr.sh_type = SHT_REL9;
1357 shdr.sh_link = section_index(ew, ew->symtab_sec);
1358 shdr.sh_info = sym->st_shndx;
1359
1360 if (ew->bit64) {
1361 shdr.sh_addralign = sizeof(Elf64_Addr);
1362 shdr.sh_entsize = sizeof(Elf64_Rel);
1363 } else {
1364 shdr.sh_addralign = sizeof(Elf32_Addr);
1365 shdr.sh_entsize = sizeof(Elf32_Rel);
1366 }
1367
1368 if ((strlen(".rel") + strlen(ew->sections[sym->st_shndx].name) + 1) >
1369 MAX_REL_NAME32) {
1370 ERROR("Rel Section name won't fit\n")fprintf(stderr, "E: " "Rel Section name won't fit\n");
1371 return NULL((void*)0);
1372 }
1373
1374 strcat(rel->name, ".rel");
1375 strcat(rel->name, ew->sections[sym->st_shndx].name);
1376 buffer_init(&b, rel->name, NULL((void*)0), 0);
1377
1378 elf_writer_add_section(ew, &shdr, &b, rel->name);
1379 rel->sec = last_section(ew);
1380
1381 return rel;
1382}
1383
1384static int add_rel(struct elf_writer_rel *rel_sec, const Elf64_Rel *rel)
1385{
1386 if (rel_sec->num_entries == rel_sec->max_entries) {
1387 size_t num = rel_sec->max_entries * 2;
1388 Elf64_Rel *old_rels;
1389
1390 if (num == 0)
1391 num = 128;
1392
1393 old_rels = rel_sec->rels;
1394 rel_sec->rels = calloc(num, sizeof(Elf64_Rel));
1395
1396 memcpy(rel_sec->rels, old_rels,
1397 rel_sec->num_entries * sizeof(Elf64_Rel));
1398 free(old_rels);
1399
1400 rel_sec->max_entries = num;
1401 }
1402
1403 rel_sec->rels[rel_sec->num_entries] = *rel;
1404 rel_sec->num_entries++;
1405
1406 return 0;
1407}
1408
1409int elf_writer_add_rel(struct elf_writer *ew, const char *sym, Elf64_Addr addr)
1410{
1411 Elf64_Rel rel;
1412 Elf64_Xword sym_info;
1413 int sym_index;
1414 struct elf_writer_rel *rel_sec;
1415
1416 sym_index = elf_sym_index(ew, sym);
1417
1418 if (sym_index < 0) {
1419 ERROR("Unable to locate symbol: %s\n", sym)fprintf(stderr, "E: " "Unable to locate symbol: %s\n", sym);
1420 return -1;
1421 }
1422
1423 sym_info = sym_index;
1424
1425 /* The relocation type will get fixed prior to serialization. */
1426 rel.r_offset = addr;
1427 rel.r_info = ELF64_R_INFO(sym_info, 0)((((Elf64_Xword) (sym_info)) << 32) + (0));
1428
1429 rel_sec = rel_section(ew, &rel);
1430
1431 if (rel_sec == NULL((void*)0))
1432 return -1;
1433
1434 return add_rel(rel_sec, &rel);
1435}
1436
1437int elf_program_file_size(const struct buffer *input, size_t *file_size)
1438{
1439 Elf64_Ehdr ehdr;
1440 Elf64_Phdr *phdr;
1441 int i;
1442 size_t loadable_file_size = 0;
1443
1444 if (elf_headers(input, &ehdr, &phdr, NULL((void*)0)))
1445 return -1;
1446
1447 for (i = 0; i < ehdr.e_phnum; i++) {
1448 if (phdr[i].p_type != PT_LOAD1)
1449 continue;
1450 loadable_file_size += phdr[i].p_filesz;
1451 }
1452
1453 *file_size = loadable_file_size;
1454
1455 free(phdr);
1456
1457 return 0;
1458}