Store hidelist in magisk database

native/jni/magiskhide/proc_monitor.cpp

@@ -0,0 +1,202 @@
+/* proc_monitor.cpp - Monitor am_proc_start events and unmount
+ *
+ * We monitor the logcat am_proc_start events. When a target starts up,
+ * we pause it ASAP, and fork a new process to join its mount namespace
+ * and do all the unmounting/mocking
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <pthread.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <sys/mount.h>
+
+#include "magisk.h"
+#include "daemon.h"
+#include "utils.hpp"
+#include "magiskhide.h"
+#include "flags.h"
+
+static int sockfd = -1;
+
+// Workaround for the lack of pthread_cancel
+static void term_thread(int) {
+	LOGD("proc_monitor: running cleanup\n");
+	destroy_list();
+	hide_enabled = 0;
+	close(sockfd);
+	sockfd = -1;
+	pthread_mutex_destroy(&list_lock);
+	LOGD("proc_monitor: terminating\n");
+	pthread_exit(NULL);
+}
+
+static int read_ns(const int pid, struct stat *st) {
+	char path[32];
+	sprintf(path, "/proc/%d/ns/mnt", pid);
+	return stat(path, st);
+}
+
+static void lazy_unmount(const char* mountpoint) {
+	if (umount2(mountpoint, MNT_DETACH) != -1)
+		LOGD("hide_daemon: Unmounted (%s)\n", mountpoint);
+}
+
+static int parse_ppid(int pid) {
+	char stat[512], path[32];
+	int fd, ppid;
+	sprintf(path, "/proc/%d/stat", pid);
+	fd = xopen(path, O_RDONLY);
+	xread(fd, stat, sizeof(stat));
+	close(fd);
+	/* PID COMM STATE PPID ..... */
+	sscanf(stat, "%*d %*s %*c %d", &ppid);
+	return ppid;
+}
+
+static void hide_daemon(int pid) {
+	LOGD("hide_daemon: start unmount for pid=[%d]\n", pid);
+
+	char buffer[PATH_MAX];
+	auto mounts = Array<char *>();
+
+	manage_selinux();
+	clean_magisk_props();
+
+	if (switch_mnt_ns(pid))
+		goto exit;
+
+	snprintf(buffer, sizeof(buffer), "/proc/%d/mounts", pid);
+	file_to_array(buffer, mounts);
+
+	// Unmount dummy skeletons and /sbin links
+	for (auto &s : mounts) {
+		if (strstr(s, "tmpfs /system/") || strstr(s, "tmpfs /vendor/") || strstr(s, "tmpfs /sbin")) {
+			sscanf(s, "%*s %4096s", buffer);
+			lazy_unmount(buffer);
+		}
+		free(s);
+	}
+	mounts.clear();
+
+	// Re-read mount infos
+	snprintf(buffer, sizeof(buffer), "/proc/%d/mounts", pid);
+	file_to_array(buffer, mounts);
+
+	// Unmount everything under /system, /vendor, and loop mounts
+	for (auto &s : mounts) {
+		if (strstr(s, "/dev/block/loop") || strstr(s, " /system/") || strstr(s, " /vendor/")) {
+			sscanf(s, "%*s %4096s", buffer);
+			lazy_unmount(buffer);
+		}
+		free(s);
+	}
+	mounts.clear();
+
+exit:
+	// Send resume signal
+	kill(pid, SIGCONT);
+	_exit(0);
+}
+
+void proc_monitor() {
+	// Unblock user signals
+	sigset_t block_set;
+	sigemptyset(&block_set);
+	sigaddset(&block_set, TERM_THREAD);
+	pthread_sigmask(SIG_UNBLOCK, &block_set, NULL);
+
+	// Register the cancel signal
+	struct sigaction act;
+	memset(&act, 0, sizeof(act));
+	act.sa_handler = term_thread;
+	sigaction(TERM_THREAD, &act, NULL);
+
+	if (access("/proc/1/ns/mnt", F_OK) != 0) {
+		LOGE("proc_monitor: Your kernel doesn't support mount namespace :(\n");
+		term_thread(TERM_THREAD);
+	}
+
+	// Connect to the log daemon
+	sockfd = connect_log_daemon();
+	if (sockfd < 0)
+		return;
+	write_int(sockfd, HIDE_CONNECT);
+
+	FILE *log_in = fdopen(sockfd, "r");
+	char buf[4096];
+	while (fgets(buf, sizeof(buf), log_in)) {
+		char *ss = strchr(buf, '[');
+		int pid, ppid, num = 0;
+		char *pos = ss, proc[256];
+		struct stat ns, pns;
+
+		while(1) {
+			pos = strchr(pos, ',');
+			if(pos == NULL)
+				break;
+			pos[0] = ' ';
+			++num;
+		}
+
+		if(sscanf(ss, num == 6 ? "[%*d %d %*d %*d %256s" : "[%*d %d %*d %256s", &pid, proc) != 2)
+			continue;
+
+		// Make sure our target is alive
+		if (kill(pid, 0))
+			continue;
+
+		// Allow hiding sub-services of applications
+		char *colon = strchr(proc, ':');
+		if (colon)
+			*colon = '\0';
+
+		bool hide = false;
+		pthread_mutex_lock(&list_lock);
+		for (auto &s : hide_list) {
+			if (strcmp(proc, s) == 0) {
+				hide = true;
+				break;
+			}
+		}
+		pthread_mutex_unlock(&list_lock);
+		if (!hide)
+			continue;
+
+		ppid = parse_ppid(pid);
+		read_ns(ppid, &pns);
+		do {
+			read_ns(pid, &ns);
+			if (ns.st_dev == pns.st_dev && ns.st_ino == pns.st_ino)
+				usleep(50);
+			else
+				break;
+		} while (1);
+
+		// Send pause signal ASAP
+		if (kill(pid, SIGSTOP) == -1)
+			continue;
+
+		// Restore the colon so we can log the actual process name
+		if (colon)
+			*colon = ':';
+#ifdef MAGISK_DEBUG
+		LOGI("proc_monitor: %s (PID=[%d] ns=%llu)(PPID=[%d] ns=%llu)\n",
+			 proc, pid, ns.st_ino, ppid, pns.st_ino);
+#else
+		LOGI("proc_monitor: %s\n", proc);
+#endif
+
+		/*
+		 * The setns system call do not support multithread processes
+		 * We have to fork a new process, setns, then do the unmounts
+		 */
+		if (fork_dont_care() == 0)
+			hide_daemon(pid);
+	}
+}