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Connect to magiskd log daemon

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This commit is contained in:
topjohnwu
2021-08-21 03:52:59 -07:00
parent bade4f2c6a
commit 171d68ca72
7 changed files with 163 additions and 39 deletions
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105
native/jni/zygisk/hook.cpp
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@@ -24,10 +24,12 @@ namespace {
enum {
DENY_FLAG,
FORK_AND_SPECIALIZE,
APP_SPECIALIZE,
SERVER_SPECIALIZE,
FLAG_MAX
};
#define DCL_JNI_FUNC(name) \
#define DCL_PRE_POST(name) \
void name##_pre(); \
void name##_post();
@@ -44,15 +46,17 @@ struct HookContext {
HookContext() : pid(-1) {}
void pre_fork();
static void post_fork();
static void close_fds();
DCL_JNI_FUNC(nativeForkAndSpecialize)
DCL_JNI_FUNC(nativeSpecializeAppProcess)
DCL_JNI_FUNC(nativeForkSystemServer)
DCL_PRE_POST(fork)
DCL_PRE_POST(run_modules)
DCL_PRE_POST(nativeForkAndSpecialize)
DCL_PRE_POST(nativeSpecializeAppProcess)
DCL_PRE_POST(nativeForkSystemServer)
};
#undef DCL_JNI_FUNC
#undef DCL_PRE_POST
struct StringCmp {
using is_transparent = void;
@@ -127,15 +131,15 @@ DCL_HOOK_FUNC(int, jniRegisterNativeMethods,
return old_jniRegisterNativeMethods(env, className, newMethods.get() ?: methods, numMethods);
}
// Skip actual fork and return cached result if applicable
DCL_HOOK_FUNC(int, fork) {
return (g_ctx && g_ctx->pid >= 0) ? g_ctx->pid : old_fork();
}
// This is the latest point where we can still connect to the magiskd main socket
DCL_HOOK_FUNC(int, selinux_android_setcontext,
uid_t uid, int isSystemServer, const char *seinfo, const char *pkgname) {
if (g_ctx && g_ctx->flags[DENY_FLAG]) {
// Request magiskd to cleanup our mount namespace before switching secontext
// This is the latest point where we can still connect to the magiskd main socket
if (remote_request_unmount() == 0) {
LOGD("zygisk: mount namespace cleaned up\n");
}
@@ -143,6 +147,16 @@ DCL_HOOK_FUNC(int, selinux_android_setcontext,
return old_selinux_android_setcontext(uid, isSystemServer, seinfo, pkgname);
}
// A place to clean things up before calling into zygote::ForkCommon/SpecializeCommon
DCL_HOOK_FUNC(void, android_log_close) {
HookContext::close_fds();
if (g_ctx && g_ctx->pid <= 0) {
// In child process, no longer be able to access to magiskd
android_logging();
}
old_android_log_close();
}
// -----------------------------------------------------------------
// The original android::AppRuntime virtual table
@@ -208,8 +222,18 @@ DCL_HOOK_FUNC(void, setArgv0, void *self, const char *argv0, bool setProcName) {
// -----------------------------------------------------------------
void HookContext::run_modules_pre() { /* TODO */ }
void HookContext::run_modules_post() { /* TODO */ }
void HookContext::close_fds() {
close(logd_fd.exchange(-1));
}
// -----------------------------------------------------------------
void HookContext::nativeSpecializeAppProcess_pre() {
g_ctx = this;
flags[APP_SPECIALIZE] = true;
process = env->GetStringUTFChars(args->nice_name, nullptr);
if (flags[FORK_AND_SPECIALIZE]) {
VLOG("zygisk: pre forkAndSpecialize [%s]\n", process);
@@ -221,6 +245,8 @@ void HookContext::nativeSpecializeAppProcess_pre() {
if (args->mount_external != 0 && remote_check_denylist(args->uid, process)) {
flags[DENY_FLAG] = true;
LOGI("zygisk: [%s] is on the denylist\n", process);
} else {
run_modules_pre();
}
}
@@ -232,24 +258,49 @@ void HookContext::nativeSpecializeAppProcess_post() {
}
env->ReleaseStringUTFChars(args->nice_name, process);
if (flags[DENY_FLAG])
if (flags[DENY_FLAG]) {
self_unload();
} else {
run_modules_post();
}
g_ctx = nullptr;
}
void HookContext::nativeForkSystemServer_pre() {
pre_fork();
if (pid) return;
VLOG("zygisk: pre forkSystemServer\n");
fork_pre();
flags[SERVER_SPECIALIZE] = true;
if (pid == 0) {
VLOG("zygisk: pre forkSystemServer\n");
run_modules_pre();
close_fds();
}
}
void HookContext::nativeForkSystemServer_post() {
run_finally f([]{ post_fork(); });
if (pid) return;
VLOG("zygisk: post forkSystemServer\n");
if (pid == 0) {
android_logging();
VLOG("zygisk: post forkSystemServer\n");
run_modules_post();
}
fork_post();
}
// -----------------------------------------------------------------
void HookContext::nativeForkAndSpecialize_pre() {
fork_pre();
flags[FORK_AND_SPECIALIZE] = true;
if (pid == 0) {
nativeSpecializeAppProcess_pre();
close_fds();
}
}
void HookContext::nativeForkAndSpecialize_post() {
if (pid == 0) {
android_logging();
nativeSpecializeAppProcess_post();
}
fork_post();
}
int sigmask(int how, int signum) {
sigset_t set;
@@ -260,31 +311,18 @@ int sigmask(int how, int signum) {
// Do our own fork before loading any 3rd party code
// First block SIGCHLD, unblock after original fork is done
void HookContext::pre_fork() {
void HookContext::fork_pre() {
g_ctx = this;
sigmask(SIG_BLOCK, SIGCHLD);
pid = old_fork();
}
// Unblock SIGCHLD in case the original method didn't
void HookContext::post_fork() {
void HookContext::fork_post() {
sigmask(SIG_UNBLOCK, SIGCHLD);
g_ctx = nullptr;
}
void HookContext::nativeForkAndSpecialize_pre() {
pre_fork();
flags[FORK_AND_SPECIALIZE] = true;
if (pid == 0)
nativeSpecializeAppProcess_pre();
}
void HookContext::nativeForkAndSpecialize_post() {
if (pid == 0)
nativeSpecializeAppProcess_post();
post_fork();
}
} // namespace
static bool hook_refresh() {
@@ -315,7 +353,7 @@ static int hook_register(const char *path, const char *symbol, void *new_func, v
XHOOK_REGISTER_SYM(PATH_REGEX, #NAME, NAME)
#define ANDROID_RUNTIME ".*/libandroid_runtime.so$"
#define APP_PROCESS "^/system/bin/app_process.*"
#define APP_PROCESS "^/system/bin/app_process.*"
void hook_functions() {
#ifdef MAGISK_DEBUG
@@ -329,6 +367,7 @@ void hook_functions() {
XHOOK_REGISTER(ANDROID_RUNTIME, fork);
XHOOK_REGISTER(ANDROID_RUNTIME, selinux_android_setcontext);
XHOOK_REGISTER(ANDROID_RUNTIME, jniRegisterNativeMethods);
XHOOK_REGISTER_SYM(ANDROID_RUNTIME, "__android_log_close", android_log_close);
hook_refresh();
// Remove unhooked methods