static char*
_elf_item(Elf *elf, Elf_Type type, size_t n, size_t off, int *flag) {
Elf_Data src, dst;
*flag = 0;
elf_assert(n);
elf_assert(valid_type(type));
if (off > elf->e_size) {
seterr(ERROR_OUTSIDE);
return NULL;
}
src.d_type = type;
src.d_version = elf->e_version;
src.d_size = n * _fsize(elf->e_class, src.d_version, type);
elf_assert(src.d_size);
if ((elf->e_size - off) < src.d_size) {
seterr(truncerr(type));
return NULL;
}
dst.d_version = _elf_version;
dst.d_size = n * _msize(elf->e_class, dst.d_version, type);
elf_assert(dst.d_size);
elf_assert(elf->e_data);
if (elf->e_rawdata != elf->e_data && dst.d_size <= src.d_size) {
dst.d_buf = elf->e_data + off;
}
else if (!(dst.d_buf = malloc(dst.d_size))) {
seterr(memerr(type));
return NULL;
}
else {
*flag = 1;
}
if (elf->e_rawdata) {
src.d_buf = elf->e_rawdata + off;
}
else {
src.d_buf = elf->e_data + off;
}
if (_elf_xlatetom(elf, &dst, &src)) {
if (!*flag) {
elf->e_cooked = 1;
}
return (char*)dst.d_buf;
}
if (*flag) {
free(dst.d_buf);
*flag = 0;
}
return NULL;
}
static char*
_elf_item(void *buf, Elf *elf, Elf_Type type, size_t off) {
Elf_Data src, dst;
elf_assert(valid_type(type));
if (off < 0 || off > elf->e_size) {
seterr(ERROR_OUTSIDE);
return NULL;
}
src.d_type = type;
src.d_version = elf->e_version;
src.d_size = _fsize(elf->e_class, src.d_version, type);
elf_assert(src.d_size);
if ((elf->e_size - off) < src.d_size) {
seterr(truncerr(type));
return NULL;
}
dst.d_version = _elf_version;
dst.d_size = _msize(elf->e_class, dst.d_version, type);
elf_assert(dst.d_size);
if (!(dst.d_buf = buf) && !(dst.d_buf = malloc(dst.d_size))) {
seterr(memerr(type));
return NULL;
}
elf_assert(elf->e_data);
if (elf->e_rawdata) {
src.d_buf = elf->e_rawdata + off;
}
else {
src.d_buf = elf->e_data + off;
}
if (_elf_xlatetom(elf, &dst, &src)) {
return (char*)dst.d_buf;
}
if (dst.d_buf != buf) {
free(dst.d_buf);
}
return NULL;
}
static int
_elf_cook_phdr(Elf *elf) {
size_t num, off, entsz;
if (elf->e_class == ELFCLASS32) {
num = ((Elf32_Ehdr*)elf->e_ehdr)->e_phnum;
off = ((Elf32_Ehdr*)elf->e_ehdr)->e_phoff;
entsz = ((Elf32_Ehdr*)elf->e_ehdr)->e_phentsize;
}
#if __LIBELF64
else if (elf->e_class == ELFCLASS64) {
num = ((Elf64_Ehdr*)elf->e_ehdr)->e_phnum;
off = ((Elf64_Ehdr*)elf->e_ehdr)->e_phoff;
entsz = ((Elf64_Ehdr*)elf->e_ehdr)->e_phentsize;
/*
* Check for overflow on 32-bit systems
*/
if (overflow(off, ((Elf64_Ehdr*)elf->e_ehdr)->e_phoff, Elf64_Off)) {
seterr(ERROR_OUTSIDE);
return 0;
}
}
#endif /* __LIBELF64 */
else {
seterr(ERROR_UNIMPLEMENTED);
return 0;
}
if (off) {
Elf_Scn *scn;
size_t size;
unsigned i;
char *p;
if (num == PN_XNUM) {
/*
* Overflow in ehdr->e_phnum.
* Get real value from first SHDR.
*/
if (!(scn = elf->e_scn_1)) {
seterr(ERROR_NOSUCHSCN);
return 0;
}
if (elf->e_class == ELFCLASS32) {
num = scn->s_shdr32.sh_info;
}
#if __LIBELF64
else if (elf->e_class == ELFCLASS64) {
num = scn->s_shdr64.sh_info;
}
#endif /* __LIBELF64 */
/* we already had this
else {
seterr(ERROR_UNIMPLEMENTED);
return 0;
}
*/
}
size = _fsize(elf->e_class, elf->e_version, ELF_T_PHDR);
elf_assert(size);
#if ENABLE_EXTENDED_FORMAT
if (entsz < size) {
#else /* ENABLE_EXTENDED_FORMAT */
if (entsz != size) {
#endif /* ENABLE_EXTENDED_FORMAT */
seterr(ERROR_EHDR_PHENTSIZE);
return 0;
}
size = _msize(elf->e_class, _elf_version, ELF_T_PHDR);
elf_assert(size);
if (!(p = malloc(num * size))) {
seterr(memerr(ELF_T_PHDR));
return 0;
}
for (i = 0; i < num; i++) {
if (!_elf_item(p + i * size, elf, ELF_T_PHDR, off + i * entsz)) {
free(p);
return 0;
}
}
elf->e_phdr = p;
elf->e_phnum = num;
}
return 1;
}
static int
_elf_cook_shdr(Elf *elf) {
size_t num, off, entsz;
if (elf->e_class == ELFCLASS32) {
num = ((Elf32_Ehdr*)elf->e_ehdr)->e_shnum;
off = ((Elf32_Ehdr*)elf->e_ehdr)->e_shoff;
entsz = ((Elf32_Ehdr*)elf->e_ehdr)->e_shentsize;
}
#if __LIBELF64
else if (elf->e_class == ELFCLASS64) {
num = ((Elf64_Ehdr*)elf->e_ehdr)->e_shnum;
off = ((Elf64_Ehdr*)elf->e_ehdr)->e_shoff;
entsz = ((Elf64_Ehdr*)elf->e_ehdr)->e_shentsize;
/*
* Check for overflow on 32-bit systems
*/
if (overflow(off, ((Elf64_Ehdr*)elf->e_ehdr)->e_shoff, Elf64_Off)) {
seterr(ERROR_OUTSIDE);
return 0;
}
}
#endif /* __LIBELF64 */
else {
seterr(ERROR_UNIMPLEMENTED);
return 0;
}
if (off) {
struct tmp {
Elf_Scn scn;
Scn_Data data;
} *head;
Elf_Data src, dst;
Elf_Scn *scn;
Scn_Data *sd;
unsigned i;
if (off < 0 || off > elf->e_size) {
seterr(ERROR_OUTSIDE);
return 0;
}
src.d_type = ELF_T_SHDR;
src.d_version = elf->e_version;
src.d_size = _fsize(elf->e_class, src.d_version, ELF_T_SHDR);
elf_assert(src.d_size);
#if ENABLE_EXTENDED_FORMAT
if (entsz < src.d_size) {
#else /* ENABLE_EXTENDED_FORMAT */
if (entsz != src.d_size) {
#endif /* ENABLE_EXTENDED_FORMAT */
seterr(ERROR_EHDR_SHENTSIZE);
return 0;
}
dst.d_version = EV_CURRENT;
if (num == 0) {
union {
Elf32_Shdr sh32;
#if __LIBELF64
Elf64_Shdr sh64;
#endif /* __LIBELF64 */
} u;
/*
* Overflow in ehdr->e_shnum.
* Get real value from first SHDR.
*/
if (elf->e_size - off < entsz) {
seterr(ERROR_TRUNC_SHDR);
return 0;
}
if (elf->e_rawdata) {
src.d_buf = elf->e_rawdata + off;
}
else {
src.d_buf = elf->e_data + off;
}
dst.d_buf = &u;
dst.d_size = sizeof(u);
if (!_elf_xlatetom(elf, &dst, &src)) {
return 0;
}
elf_assert(dst.d_size == _msize(elf->e_class, EV_CURRENT, ELF_T_SHDR));
elf_assert(dst.d_type == ELF_T_SHDR);
if (elf->e_class == ELFCLASS32) {
num = u.sh32.sh_size;
}
#if __LIBELF64
else if (elf->e_class == ELFCLASS64) {
num = u.sh64.sh_size;
/*
* Check for overflow on 32-bit systems
*/
if (overflow(num, u.sh64.sh_size, Elf64_Xword)) {
seterr(ERROR_OUTSIDE);
return 0;
}
}
#endif /* __LIBELF64 */
}
if ((elf->e_size - off) / entsz < num) {
seterr(ERROR_TRUNC_SHDR);
return 0;
}
if (!(head = (struct tmp*)malloc(num * sizeof(struct tmp)))) {
seterr(ERROR_MEM_SCN);
return 0;
}
for (scn = NULL, i = num; i-- > 0; ) {
head[i].scn = _elf_scn_init;
head[i].data = _elf_data_init;
head[i].scn.s_link = scn;
if (!scn) {
elf->e_scn_n = &head[i].scn;
}
scn = &head[i].scn;
sd = &head[i].data;
if (elf->e_rawdata) {
src.d_buf = elf->e_rawdata + off + i * entsz;
}
else {
src.d_buf = elf->e_data + off + i * entsz;
}
dst.d_buf = &scn->s_uhdr;
dst.d_size = sizeof(scn->s_uhdr);
if (!_elf_xlatetom(elf, &dst, &src)) {
elf->e_scn_n = NULL;
free(head);
return 0;
}
elf_assert(dst.d_size == _msize(elf->e_class, EV_CURRENT, ELF_T_SHDR));
elf_assert(dst.d_type == ELF_T_SHDR);
scn->s_elf = elf;
scn->s_index = i;
scn->s_data_1 = sd;
scn->s_data_n = sd;
sd->sd_scn = scn;
if (elf->e_class == ELFCLASS32) {
Elf32_Shdr *shdr = &scn->s_shdr32;
scn->s_type = shdr->sh_type;
scn->s_size = shdr->sh_size;
scn->s_offset = shdr->sh_offset;
sd->sd_data.d_align = shdr->sh_addralign;
sd->sd_data.d_type = _elf_scn_type(scn->s_type);
}
#if __LIBELF64
else if (elf->e_class == ELFCLASS64) {
Elf64_Shdr *shdr = &scn->s_shdr64;
scn->s_type = shdr->sh_type;
scn->s_size = shdr->sh_size;
scn->s_offset = shdr->sh_offset;
sd->sd_data.d_align = shdr->sh_addralign;
/*
* Check for overflow on 32-bit systems
*/
if (overflow(scn->s_size, shdr->sh_size, Elf64_Xword)
|| overflow(scn->s_offset, shdr->sh_offset, Elf64_Off)
|| overflow(sd->sd_data.d_align, shdr->sh_addralign, Elf64_Xword)) {
seterr(ERROR_OUTSIDE);
return 0;
}
sd->sd_data.d_type = _elf_scn_type(scn->s_type);
/*
* QUIRKS MODE:
*
* Some 64-bit architectures use 64-bit entries in the
* .hash section. This violates the ELF standard, and
* should be fixed. It's mostly harmless as long as the
* binary and the machine running your program have the
* same byte order, but you're in trouble if they don't,
* and if the entry size is wrong.
*
* As a workaround, I let libelf guess the right size
* for the binary. This relies pretty much on the fact
* that the binary provides correct data in the section
* headers. If it doesn't, it's probably broken anyway.
* Therefore, libelf uses a standard conforming value
* when it's not absolutely sure.
*/
if (scn->s_type == SHT_HASH) {
int override = 0;
/*
* sh_entsize must reflect the entry size
*/
if (shdr->sh_entsize == ELF64_FSZ_ADDR) {
override++;
}
/*
* sh_size must be a multiple of sh_entsize
*/
if (shdr->sh_size % ELF64_FSZ_ADDR == 0) {
override++;
}
/*
* There must be room for at least 2 entries
*/
if (shdr->sh_size >= 2 * ELF64_FSZ_ADDR) {
override++;
}
/*
* sh_addralign must be correctly set
*/
if (shdr->sh_addralign == ELF64_FSZ_ADDR) {
override++;
}
/*
* The section must be properly aligned
*/
if (shdr->sh_offset % ELF64_FSZ_ADDR == 0) {
override++;
}
/* XXX: also look at the data? */
/*
* Make a conservative decision...
*/
if (override >= 5) {
sd->sd_data.d_type = ELF_T_ADDR;
}
}
/*
* END QUIRKS MODE.
*/
}
#endif /* __LIBELF64 */
/* we already had this
else {
seterr(ERROR_UNIMPLEMENTED);
return 0;
}
*/
sd->sd_data.d_size = scn->s_size;
sd->sd_data.d_version = _elf_version;
}
elf_assert(scn == &head[0].scn);
elf->e_scn_1 = &head[0].scn;
head[0].scn.s_freeme = 1;
}
static Elf_Data*
_elf_cook_scn(Elf *elf, Elf_Scn *scn, Scn_Data *sd) {
Elf_Data dst;
Elf_Data src;
int flag = 0;
size_t dlen;
elf_assert(elf->e_data);
/*
* Prepare source
*/
src = sd->sd_data;
src.d_version = elf->e_version;
if (elf->e_rawdata) {
src.d_buf = elf->e_rawdata + scn->s_offset;
}
else {
src.d_buf = elf->e_data + scn->s_offset;
}
/*
* Prepare destination (needs prepared source!)
*/
dst = sd->sd_data;
if (elf->e_class == ELFCLASS32) {
dlen = _elf32_xltsize(&src, dst.d_version, elf->e_encoding, 0);
}
#if __LIBELF64
else if (elf->e_class == ELFCLASS64) {
dlen = _elf64_xltsize(&src, dst.d_version, elf->e_encoding, 0);
}
#endif /* __LIBELF64 */
else {
elf_assert(valid_class(elf->e_class));
seterr(ERROR_UNIMPLEMENTED);
return NULL;
}
if (dlen == (size_t)-1) {
return NULL;
}
dst.d_size = dlen;
if (elf->e_rawdata != elf->e_data && dst.d_size <= src.d_size) {
dst.d_buf = elf->e_data + scn->s_offset;
}
else if (!(dst.d_buf = malloc(dst.d_size))) {
seterr(ERROR_MEM_SCNDATA);
return NULL;
}
else {
flag = 1;
}
/*
* Translate data
*/
if (_elf_xlatetom(elf, &dst, &src)) {
sd->sd_memdata = (char*)dst.d_buf;
sd->sd_data = dst;
if (!(sd->sd_free_data = flag)) {
elf->e_cooked = 1;
}
return &sd->sd_data;
}
if (flag) {
free(dst.d_buf);
}
return NULL;
}