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/*
* Copyright 2003-2024 Gentoo Foundation
* Distributed under the terms of the GNU General Public License v2
*
* Copyright 2005-2012 Ned Ludd - <solar@gentoo.org>
* Copyright 2005-2024 Mike Frysinger - <vapier@gentoo.org>
* 2008-2021 Fabian Groffen - <grobian@gentoo.org>
*/
#include "paxinc.h"
/* lil' static string pool */
static const char STR_BE[] = "BE";
static const char STR_LE[] = "LE";
static const char STR_PPC[] = "ppc";
static const char STR_PPC64[] = "ppc64";
static const char STR_I386[] = "i386";
static const char STR_X86_64[] = "x86_64";
static const char STR_ARM[] = "arm"; /* iPhone */
static const char STR_ARM64[] = "arm64"; /* Apple M1 */
static const char STR_UNKNOWN[] = "unknown";
#define QUERY(n) { #n, n }
typedef const struct {
const char *str;
unsigned int value;
} pairtype;
static inline const char *find_pairtype(pairtype *pt, unsigned int type)
{
size_t i;
for (i = 0; pt[i].str; ++i)
if (type == pt[i].value)
return pt[i].str;
return "UNKNOWN TYPE";
}
/* translate misc mach-o MH_ defines */
static pairtype macho_mh_type[] = {
QUERY(MH_OBJECT),
QUERY(MH_EXECUTE),
QUERY(MH_BUNDLE),
QUERY(MH_DYLIB),
QUERY(MH_PRELOAD),
QUERY(MH_CORE),
QUERY(MH_DYLINKER),
QUERY(MH_DYLIB_STUB),
QUERY(MH_DSYM),
{ 0, 0 }
};
const char *get_machomhtype(fatobj *fobj)
{
/* can use 32-bits header, since 64 and 32 are aligned here */
return find_pairtype(macho_mh_type, MOBJGET(fobj, mhdr.hdr32->filetype));
}
/* translate misc mach-o MH_ flags */
static pairtype macho_mh_flag[] = {
QUERY(MH_NOUNDEFS),
QUERY(MH_INCRLINK),
QUERY(MH_DYLDLINK),
QUERY(MH_TWOLEVEL),
QUERY(MH_BINDATLOAD),
QUERY(MH_PREBOUND),
QUERY(MH_PREBINDABLE),
QUERY(MH_NOFIXPREBINDING),
QUERY(MH_ALLMODSBOUND),
QUERY(MH_CANONICAL),
QUERY(MH_SPLIT_SEGS),
QUERY(MH_FORCE_FLAT),
QUERY(MH_SUBSECTIONS_VIA_SYMBOLS),
QUERY(MH_NOMULTIDEFS),
{ 0, 0 }
};
void get_machomhflags(fatobj *fobj, char **ret, size_t *ret_len)
{
uint32_t flags;
int i;
char first = 1;
/* can use 32-bits header, since 64 and 32 are aligned here */
flags = MOBJGET(fobj, mhdr.hdr32->flags);
for (i = 0; macho_mh_flag[i].str; ++i)
if ((flags & macho_mh_flag[i].value) == macho_mh_flag[i].value) {
if (!first)
xchrcat(ret, ',', ret_len);
xstrcat(ret, macho_mh_flag[i].str, ret_len);
first = 0;
}
}
static pairtype macho_cputype[] = {
QUERY(CPU_TYPE_POWERPC),
QUERY(CPU_TYPE_I386),
QUERY(CPU_TYPE_ARM),
QUERY(CPU_TYPE_POWERPC64),
QUERY(CPU_TYPE_X86_64),
QUERY(CPU_TYPE_ARM64),
{ 0, 0 }
};
const char *get_machocputype(fatobj *fobj)
{
/* can use 32-bits header, since 64 and 32 are aligned here */
const char *ret = find_pairtype(macho_cputype, MOBJGET(fobj, mhdr.hdr32->cputype));
return ret + sizeof("CPU_TYPE_") - 1;
}
/* translate cpusubtypes */
static pairtype macho_cpusubtypeppc[] = {
QUERY(CPU_SUBTYPE_POWERPC_ALL),
QUERY(CPU_SUBTYPE_POWERPC_601),
QUERY(CPU_SUBTYPE_POWERPC_602),
QUERY(CPU_SUBTYPE_POWERPC_603),
QUERY(CPU_SUBTYPE_POWERPC_603e),
QUERY(CPU_SUBTYPE_POWERPC_603ev),
QUERY(CPU_SUBTYPE_POWERPC_604),
QUERY(CPU_SUBTYPE_POWERPC_604e),
QUERY(CPU_SUBTYPE_POWERPC_620),
QUERY(CPU_SUBTYPE_POWERPC_750),
QUERY(CPU_SUBTYPE_POWERPC_7400),
QUERY(CPU_SUBTYPE_POWERPC_7450),
QUERY(CPU_SUBTYPE_POWERPC_970),
{ 0, 0 }
};
static pairtype macho_cpusubtypex86[] = {
QUERY(CPU_SUBTYPE_I386_ALL),
QUERY(CPU_SUBTYPE_486),
QUERY(CPU_SUBTYPE_586),
QUERY(CPU_SUBTYPE_PENTIUM_3),
QUERY(CPU_SUBTYPE_PENTIUM_M),
QUERY(CPU_SUBTYPE_PENTIUM_4),
QUERY(CPU_SUBTYPE_ITANIUM),
QUERY(CPU_SUBTYPE_XEON),
{ 0, 0 }
};
const char *get_machosubcputype(fatobj *fobj)
{
const char *ret;
/* can use 32-bits header, since 64 and 32 are aligned here */
uint32_t type = MOBJGET(fobj, mhdr.hdr32->cputype);
pairtype *pt = NULL;
if (type == CPU_TYPE_I386 || type == CPU_TYPE_X86_64)
pt = macho_cpusubtypex86;
else if (type == CPU_TYPE_POWERPC || type == CPU_TYPE_POWERPC64)
pt = macho_cpusubtypeppc;
if (pt) {
type = MOBJGET(fobj, mhdr.hdr32->cpusubtype);
ret = find_pairtype(pt, type);
return ret + sizeof("CPU_SUBTYPE_") - 1;
} else
return STR_UNKNOWN;
}
/* Determines the type of this object, and sets the right 32-bit or
* 64-bits pointer. The ismach64 flag is filled in appropriately. The
* return of this function is the read magic value, or 0 when the file
* is not recognised.
* Note: the input addr must be enough to map on struct mach_header! */
inline static uint32_t read_mach_header(fatobj *fobj, void *addr)
{
struct mach_header *mhdr = addr;
fobj->mhdata = addr;
switch (mhdr->magic) {
case MH_CIGAM:
fobj->swapped = 1;
/* fall through */
case MH_MAGIC:
/* 32-bits */
fobj->ismach64 = 0;
fobj->mhdr.hdr32 = mhdr;
fobj->isbigendian = (*fobj->mhdata == (char)(MH_MAGIC >> 24) ? 1 : 0);
return mhdr->magic;
case MH_CIGAM_64:
fobj->swapped = 1;
/* fall through */
case MH_MAGIC_64:
/* 64-bits */
fobj->ismach64 = 1;
fobj->mhdr.hdr64 = addr;
fobj->isbigendian = (*fobj->mhdata == (char)(MH_MAGIC_64 >> 24) ? 1 : 0);
return mhdr->magic;
default:
return 0; /* unrecognised file */
}
}
/* Read a macho into memory, returning a fatobj struct with at least one
* arch. */
fatobj *readmacho(const char *filename)
{
int fd;
fatobj *ret;
if ((fd = open(filename, O_RDONLY)) == -1)
return NULL;
ret = readmacho_fd(filename, fd, 0);
if (ret == NULL)
close(fd);
return ret;
}
fatobj *readmacho_fd(const char *filename, int fd, size_t len)
{
char *data;
fatobj *ret;
if (len == 0) {
struct stat st;
if (fstat(fd, &st) == -1)
return NULL;
len = st.st_size;
if (len == 0)
return NULL;
}
data = mmap(0, len, PROT_READ, MAP_PRIVATE, fd, 0);
if (data == MAP_FAILED) {
warn("mmap on '%s' of %zu bytes failed :(", filename, len);
return NULL;
}
ret = readmacho_buffer(filename, data, len);
if (ret != NULL) {
ret->fd = fd;
return ret;
}
munmap(data, len);
return NULL;
}
fatobj *readmacho_buffer(const char *filename, char *buffer, size_t buffer_len)
{
struct fat_header *fhdr;
fatobj *ret = xmalloc(sizeof(*ret));
ret->fd = -1;
ret->filename = filename;
ret->base_filename = strrchr(ret->filename, '/');
ret->base_filename =
(ret->base_filename == NULL ? ret->filename : ret->base_filename + 1);
ret->len = buffer_len;
ret->data = buffer;
ret->swapped = 0;
/* make sure we have enough bytes to scan */
if (ret->len <= sizeof(struct fat_header))
goto fail;
fhdr = ret->data;
/* Check what kind of file this is. Unfortunately we don't have
* configure, so we don't know if we're on big or little endian, so
* we cannot check if the fat_header is in bigendian like it should.
*/
if (fhdr->magic == FAT_MAGIC || fhdr->magic == FAT_CIGAM) {
/* we're indeed in a FAT file */
uint32_t i;
fatobj *fobj = ret;
struct fat_arch *farch;
void *dptr = ret->data + sizeof(struct fat_header);
uint32_t bufleft = ret->len - sizeof(struct fat_header);
char swapped = 0;
uint32_t narchs = fhdr->nfat_arch;
uint32_t offset;
/* FAT headers are always big-endian, so swap if on little
* machines... */
if (fhdr->magic == FAT_CIGAM) {
swapped = 1;
narchs = bswap_32(narchs);
}
/* can we read the headers at all?
* beware of corrupt files and Java bytecode which shares
* the same magic with us :( */
if (sizeof(struct fat_arch) * narchs > bufleft)
goto fail;
for (i = 1; i <= narchs; i++) {
farch = (struct fat_arch *)dptr;
offset = MGET(swapped, farch->offset);
if (offset + sizeof(struct mach_header) >= bufleft ||
read_mach_header(fobj, ret->data + offset) == 0)
goto fail;
if (i < narchs) {
fobj = fobj->next = xzalloc(sizeof(*fobj));
/* filename and size are necessary for printing */
fobj->filename = ret->filename;
fobj->base_filename = ret->base_filename;
fobj->len = ret->len;
} else {
fobj->next = NULL;
}
dptr += sizeof(struct fat_arch);
bufleft -= sizeof(struct fat_arch);
}
} else {
/* simple Mach-O file, treat as single arch FAT file */
if (ret->len < sizeof(struct mach_header) ||
read_mach_header(ret, ret->data) == 0)
goto fail;
ret->next = NULL;
}
return ret;
fail:
free(ret);
return NULL;
}
/* undo the readmacho() stuff */
void unreadmacho(fatobj *macho)
{
if (macho->data != NULL) {
munmap(macho->data, macho->len);
close(macho->fd);
}
/* free all arches recursively */
if (macho->next != NULL)
unreadmacho(macho->next);
free(macho);
}
/* Returns the first load_command in the file (after the mach_header)
* and allocates a loadcmd struct to store it together with some
* convenience data. The struct can be manually freed, if not traversed
* until the end of the load section. */
loadcmd *firstloadcmd(fatobj *fobj)
{
loadcmd *ret = xmalloc(sizeof(*ret));
ret->data = fobj->mhdata +
(fobj->ismach64 ? sizeof(struct mach_header_64) : sizeof(struct mach_header));
ret->lcmd = ret->data;
ret->cleft = MOBJGET(fobj, mhdr.hdr32->ncmds); /* 32 and 64 bits are aligned here */
ret->align = (fobj->ismach64 ? 8 : 4);
ret->swapped = fobj->swapped;
/* a bit useless, but a nice consistency check for ourselves now */
if (ret->lcmd->cmdsize % ret->align != 0)
warn("cmdsize isn't properly aligned on %d bytes boundary (%d)",
ret->align, ret->lcmd->cmdsize);
return ret;
}
/* Sets up the given loadcmd struct with the next load command, or frees
* it if there are no more load commands. If a new load command was
* loaded, 1 is returned, 0 otherwise. This behaviour is useful when
* looping over all load commands, since firstloadcmd will allocate the
* loadcmd struct, and nextloadcmd will free it once all load commands
* have been seen. */
int nextloadcmd(loadcmd *lcmd)
{
uint32_t size = MOBJGET(lcmd, lcmd->cmdsize);
if (--(lcmd->cleft) == 0) {
free(lcmd);
return 0;
}
if (size % lcmd->align != 0) {
/* fix alignment, this should actually never happen, but the doc
* says we have to pad if the alignment sucks */
size += lcmd->align - (size % lcmd->align);
}
lcmd->data += size;
lcmd->lcmd = lcmd->data;
return 1;
}
const char *get_machoendian(fatobj *fobj)
{
return fobj->isbigendian ? STR_BE : STR_LE;
}
const char *get_machomtype(fatobj *fobj)
{
switch (MOBJGET(fobj, mhdr.hdr32->cputype)) {
case CPU_TYPE_POWERPC: return STR_PPC;
case CPU_TYPE_I386: return STR_I386;
case CPU_TYPE_ARM: return STR_ARM;
case CPU_TYPE_POWERPC64: return STR_PPC64;
case CPU_TYPE_X86_64: return STR_X86_64;
case CPU_TYPE_ARM64: return STR_ARM64;
default: return STR_UNKNOWN;
}
}
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