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#define IB_LOG_NAME "bundle-loader"
#define IB_LOG_TO_SYSLOG
#include "ib-log.h"
#include "darwin/mach-decls.h"
#include "substituted-messages.h"
#include <dlfcn.h>
#include <mach/mach.h>
#include <mach/mig.h>
#include <objc/runtime.h>
#include <CoreFoundation/CoreFoundation.h>
#include <syslog.h>
extern char ***_NSGetArgv(void);
static int peek(const void *buf, const void *end) {
if ((size_t) (end - buf) < sizeof(struct substituted_bundle_list_op))
return -1;
return ((struct substituted_bundle_list_op *) buf)->opc;
}
static bool pop(const void **buf, const void *end,
int *opc,
const char **name) {
const struct substituted_bundle_list_op *op;
if ((size_t) (end - *buf) < sizeof(*op))
return false;
op = *buf;
*buf += sizeof(*op);
*opc = op->opc;
if ((size_t) (end - *buf) <= op->namelen ||
((const char *) buf)[op->namelen] != '\0')
return false;
*name = *buf;
*buf += op->namelen + 1;
return true;
}
static struct {
bool initialized;
typeof(CFBundleGetBundleWithIdentifier) *CFBundleGetBundleWithIdentifier;
typeof(CFStringCreateWithCStringNoCopy) *CFStringCreateWithCStringNoCopy;
typeof(CFRelease) *CFRelease;
typeof(kCFAllocatorNull) *kCFAllocatorNull;
} cf_funcs;
static struct {
bool initialized;
typeof(objc_getClass) *objc_getClass;
} objc_funcs;
#define GET(funcs, handle, name) (funcs)->name = dlsym(handle, #name)
static void *dlopen_noload(const char *path) {
void *h = dlopen(path, RTLD_LAZY | RTLD_NOLOAD);
if (!h)
return NULL;
dlclose(h);
return dlopen(path, RTLD_LAZY);
}
static bool cf_has_bundle(const char *name) {
if (!cf_funcs.initialized) {
const char *cf =
"/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation";
void *handle = dlopen_noload(cf);
if (IB_VERBOSE)
ib_log("CF handle: %p", handle);
if (handle) {
GET(&cf_funcs, handle, CFBundleGetBundleWithIdentifier);
GET(&cf_funcs, handle, CFStringCreateWithCStringNoCopy);
GET(&cf_funcs, handle, CFRelease);
GET(&cf_funcs, handle, kCFAllocatorNull);
}
cf_funcs.initialized = true;
}
if (!cf_funcs.CFBundleGetBundleWithIdentifier)
return false;
CFStringRef str = cf_funcs.CFStringCreateWithCStringNoCopy(
NULL, name, kCFStringEncodingUTF8, *cf_funcs.kCFAllocatorNull);
if (!str)
return false;
bool ret = !!cf_funcs.CFBundleGetBundleWithIdentifier(str);
cf_funcs.CFRelease(str);
return ret;
}
static bool objc_has_class(const char *name) {
if (!objc_funcs.initialized) {
void *handle = dlopen_noload("/usr/lib/libobjc.A.dylib");
if (IB_VERBOSE)
ib_log("objc handle: %p", handle);
if (handle)
GET(&objc_funcs, handle, objc_getClass);
objc_funcs.initialized = true;
}
if (!objc_funcs.objc_getClass)
return false;
return !!objc_funcs.objc_getClass(name);
}
static void use_dylib(const char *name) {
if (IB_VERBOSE)
ib_log("loading dylib %s", name);
dlopen(name, RTLD_LAZY);
}
static void load_bundle_list(const void *buf, size_t size) {
if (IB_VERBOSE) {
ib_log("load_bundle_list: %p,%zu", buf, size);
ib_log_hex(buf, size);
}
int opc;
const char *name;
const void *end = buf + size;
while (buf != end) {
if (!pop(&buf, end, &opc, &name))
goto invalid;
bool pass;
switch (opc) {
case SUBSTITUTED_TEST_BUNDLE:
pass = cf_has_bundle(name);
if (IB_VERBOSE)
ib_log("cf_has_bundle('%s'): %d", name, pass);
if (pass)
goto pass_type;
/* fail, so... */
if (peek(buf, end) != SUBSTITUTED_TEST_BUNDLE)
goto fail;
break;
case SUBSTITUTED_TEST_CLASS:
pass = objc_has_class(name);
if (IB_VERBOSE)
ib_log("objc_has_class('%s'): %d", name, pass);
if (pass)
goto pass_type;
if (peek(buf, end) != SUBSTITUTED_TEST_CLASS)
goto fail;
break;
case SUBSTITUTED_USE_DYLIB:
use_dylib(name);
break;
pass_type:
while (peek(buf, end) == opc) {
if (!pop(&buf, end, &opc, &name))
goto invalid;
}
break;
fail:
do {
if (!pop(&buf, end, &opc, &name))
goto invalid;
} while (opc != SUBSTITUTED_USE_DYLIB);
break;
}
}
return;
invalid:
ib_log("invalid bundle list IPC data (substitute bug)");
}
static kern_return_t substituted_hello(mach_port_t service, int proto_version,
const char *argv0, void **bundle_list_p,
size_t *bundle_list_size_p) {
struct {
mach_msg_header_t hdr;
union {
struct substituted_msg_body_hello req;
struct substituted_msg_body_hello_resp resp;
} u;
mach_msg_trailer_t trailer_space;
} buf;
mach_port_t reply_port = mig_get_reply_port();
buf.hdr.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND,
MACH_MSG_TYPE_MAKE_SEND_ONCE);
buf.hdr.msgh_remote_port = service;
buf.hdr.msgh_local_port = reply_port;
buf.hdr.msgh_reserved = 0;
buf.hdr.msgh_id = SUBSTITUTED_MSG_HELLO;
buf.u.req.proto_version = proto_version;
strlcpy(buf.u.req.argv0, argv0, sizeof(buf.u.req.argv0));
size_t size = sizeof(buf.hdr) +
offsetof(struct substituted_msg_body_hello, argv0) +
strlen(buf.u.req.argv0);
size_t round = round_msg(size);
memset((char *) &buf + size, 0, round - size);
buf.hdr.msgh_size = round;
kern_return_t kr = mach_msg(&buf.hdr, MACH_RCV_MSG | MACH_SEND_MSG,
buf.hdr.msgh_size, sizeof(buf), reply_port,
MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
if (kr) {
if (kr == MACH_RCV_BODY_ERROR)
mach_msg_destroy(&buf.hdr);
return kr;
}
mach_msg_ool_descriptor_t *ool = &buf.u.resp.bundle_list_ool;
if (buf.hdr.msgh_size != sizeof(buf.hdr) + sizeof(buf.u.resp) ||
!(buf.hdr.msgh_bits & MACH_MSGH_BITS_COMPLEX) ||
buf.u.resp.body.msgh_descriptor_count != 1 ||
ool->type != MACH_MSG_OOL_DESCRIPTOR) {
kr = KERN_INVALID_ARGUMENT;
goto out;
}
if (buf.u.resp.error) {
ib_log("substituted_hello returned error %x", buf.u.resp.error);
kr = KERN_FAILURE;
goto out;
}
*bundle_list_p = ool->address;
*bundle_list_size_p = ool->size;
return KERN_SUCCESS;
out:
mach_msg_destroy(&buf.hdr);
return kr;
}
/* this is DYLD_INSERT_LIBRARIES'd, not injected. */
__attribute__((constructor))
static void init() {
mach_port_t service;
kern_return_t kr = bootstrap_look_up(bootstrap_port, "com.ex.substituted",
&service);
if (kr) {
ib_log("bootstrap_look_up com.ex.substituted: %x", kr);
return;
}
const char *argv0 = (*_NSGetArgv())[0];
void *bundle_list;
size_t bundle_list_size;
kr = substituted_hello(service, SUBSTITUTED_PROTO_VERSION, argv0,
&bundle_list, &bundle_list_size);
if (kr) {
ib_log("substituted_hello: %x", kr);
return;
}
load_bundle_list(bundle_list, bundle_list_size);
vm_deallocate(mach_task_self(), (vm_address_t) bundle_list, bundle_list_size);
/* hang onto the port */
}
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