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Proper injection entry and unloading

This commit is contained in:
topjohnwu 2021-01-06 23:59:05 -08:00
parent 2a257f327c
commit ef98eaed8f
1 changed files with 24 additions and 20 deletions
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44
native/jni/inject/entry.cpp
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@ -50,7 +50,7 @@ static void *unload_first_stage(void *) {
// Setup 1ms
timespec ts = { .tv_sec = 0, .tv_nsec = 1000000L };
while (getenv(INJECT_ENV_2))
while (getenv(INJECT_ENV_1))
nanosleep(&ts, nullptr);
// Wait another 1ms to make sure all threads left our code
@ -67,6 +67,8 @@ static void sanitize_environ() {
static string env;
for (int i = 0; environ[i]; ++i) {
if (str_starts(environ[i], INJECT_ENV_1 "="))
continue;
env += environ[i];
env += '\0';
}
@ -83,37 +85,39 @@ static void sanitize_environ() {
__attribute__((constructor))
static void inject_init() {
inject_logging();
if (char *env = getenv(INJECT_ENV_1)) {
if (getenv(INJECT_ENV_2)) {
LOGD("zygote: inject 2nd stage\n");
active_threads = 1;
unsetenv(INJECT_ENV_2);
// Get our own handle
self_handle = dlopen(INJECT_LIB_2, RTLD_LAZY);
dlclose(self_handle);
// TODO: actually inject stuffs here
// Some cleanup
sanitize_environ();
active_threads++;
new_daemon_thread(&unload_first_stage);
// Demonstrate self unloading 2nd stage
self_unload();
} else if (char *env = getenv(INJECT_ENV_1)) {
LOGD("zygote: inject 1st stage\n");
if (env[0] == '1')
unsetenv("LD_PRELOAD");
else
setenv("LD_PRELOAD", env, 1); // Restore original LD_PRELOAD
unsetenv(INJECT_ENV_1);
// Setup second stage
setenv(INJECT_ENV_2, "1", 1);
cp_afc(INJECT_LIB_1, INJECT_LIB_2);
dlopen(INJECT_LIB_2, RTLD_LAZY);
} else if (getenv(INJECT_ENV_2)) {
LOGD("zygote: inject 2nd stage\n");
active_threads = 1;
// Get our own handle
self_handle = dlopen(INJECT_LIB_2, RTLD_LAZY);
dlclose(self_handle);
// Cleanup 1st stage maps
active_threads++;
new_daemon_thread(&unload_first_stage);
unsetenv(INJECT_ENV_2);
sanitize_environ();
// TODO: actually inject stuffs, for now we demonstrate clean self unloading
self_unload();
unsetenv(INJECT_ENV_1);
}
}