1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
#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 + 1 ||
((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;
typeof(kCFStringEncodingUTF8) *kCFStringEncodingUTF8;
} cf_funcs;
static struct {
bool initialized;
typeof(objc_getClass) *objc_getClass;
} objc_funcs;
#define GET(funcs, handle, name) (funcs)->name = dlsym(handle, "_" #name)
static bool cf_has_bundle(const char *name) {
if (!cf_funcs.initialized) {
void *handle = dlopen("/System/Library/Frameworks/CoreFoundation.framework",
RTLD_LAZY | RTLD_NOLOAD);
if (handle) {
GET(&cf_funcs, handle, CFBundleGetBundleWithIdentifier);
GET(&cf_funcs, handle, CFStringCreateWithCStringNoCopy);
GET(&cf_funcs, handle, CFRelease);
GET(&cf_funcs, handle, kCFAllocatorNull);
GET(&cf_funcs, handle, kCFStringEncodingUTF8);
}
}
if (!cf_funcs.CFBundleGetBundleWithIdentifier)
return false;
CFStringRef str = cf_funcs.CFStringCreateWithCStringNoCopy(
NULL, name, *cf_funcs.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("/usr/lib/libobjc.A.dylib",
RTLD_LAZY | RTLD_NOLOAD);
if (handle)
GET(&objc_funcs, handle, objc_getClass);
}
if (!objc_funcs.objc_getClass)
return false;
return !!objc_funcs.objc_getClass(name);
}
static void use_dylib(const char *name) {
syslog(LOG_ERR, "loading dylib %s", name);
// ..
}
static void load_bundle_list(const void *buf, size_t size) {
int opc;
const char *name;
const void *end = buf + size;
while (buf != end) {
if (!pop(&buf, end, &opc, &name))
goto invalid;
switch (opc) {
case SUBSTITUTED_TEST_BUNDLE:
if (cf_has_bundle(name))
goto pass_type;
/* fail, so... */
if (peek(buf, end) != SUBSTITUTED_TEST_BUNDLE)
goto fail;
break;
case SUBSTITUTED_TEST_CLASS:
if (objc_has_class(name))
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;
}
fail:
do {
if (!pop(&buf, end, &opc, &name))
goto invalid;
} while (opc != SUBSTITUTED_USE_DYLIB);
break;
}
}
return;
invalid:
syslog(LOG_ERR, "invalid bundle list data");
}
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));
buf.hdr.msgh_size = sizeof(buf.hdr) +
sizeof(buf.u.req) +
strlen(buf.u.req.argv0);
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) {
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) {
syslog(LOG_ERR, "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) {
syslog(LOG_ERR, "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 */
}
|
