Magisk/native/jni/magiskpolicy/rules.cpp

#include <utils.hpp>
#include <magiskpolicy.hpp>

#include "sepolicy.hpp"

using namespace std;

void sepolicy::magisk_rules() {
	// Temp suppress warnings
	auto bak = log_cb.w;
	log_cb.w = nop_log;

	// This indicates API 26+
	bool new_rules = exists("untrusted_app_25");

	// Prevent anything to change sepolicy except ourselves
	deny(ALL, "kernel", "security", "load_policy");

	type(SEPOL_PROC_DOMAIN, "domain");
	permissive(SEPOL_PROC_DOMAIN);  /* Just in case something is missing */
	typeattribute(SEPOL_PROC_DOMAIN, "mlstrustedsubject");
	typeattribute(SEPOL_PROC_DOMAIN, "netdomain");
	typeattribute(SEPOL_PROC_DOMAIN, "bluetoothdomain");
	type(SEPOL_FILE_TYPE, "file_type");
	typeattribute(SEPOL_FILE_TYPE, "mlstrustedobject");

	// Make our root domain unconstrained
	allow(SEPOL_PROC_DOMAIN, ALL, ALL, ALL);
	// Allow us to do any ioctl
	if (db->policyvers >= POLICYDB_VERSION_XPERMS_IOCTL) {
		allowxperm(SEPOL_PROC_DOMAIN, ALL, "blk_file", ALL);
		allowxperm(SEPOL_PROC_DOMAIN, ALL, "fifo_file", ALL);
	}

	// Create unconstrained file type
	allow(ALL, SEPOL_FILE_TYPE, "file", ALL);
	allow(ALL, SEPOL_FILE_TYPE, "dir", ALL);
	allow(ALL, SEPOL_FILE_TYPE, "fifo_file", ALL);
	allow(ALL, SEPOL_FILE_TYPE, "chr_file", ALL);

	if (new_rules) {
		// Make client type literally untrusted_app
		type(SEPOL_CLIENT_DOMAIN, "domain");
		typeattribute(SEPOL_CLIENT_DOMAIN, "coredomain");
		typeattribute(SEPOL_CLIENT_DOMAIN, "appdomain");
		typeattribute(SEPOL_CLIENT_DOMAIN, "untrusted_app_all");
		typeattribute(SEPOL_CLIENT_DOMAIN, "netdomain");
		typeattribute(SEPOL_CLIENT_DOMAIN, "bluetoothdomain");

		type(SEPOL_EXEC_TYPE, "file_type");
		typeattribute(SEPOL_EXEC_TYPE, "exec_type");

		// Basic su client needs
		allow(SEPOL_CLIENT_DOMAIN, SEPOL_EXEC_TYPE, "file", ALL);
		allow(SEPOL_CLIENT_DOMAIN, SEPOL_CLIENT_DOMAIN, ALL, ALL);

		// Allow su client termios ioctl
		const char *pts[] {
			"devpts", "untrusted_app_devpts",
			"untrusted_app_25_devpts", "untrusted_app_all_devpts" };
		for (auto type : pts) {
			allowxperm(SEPOL_CLIENT_DOMAIN, type, "chr_file", "0x5400-0x54FF");
		}

		// Allow these processes to access MagiskSU
		vector<const char *> clients{ "init", "shell", "update_engine", "appdomain" };
		for (auto type : clients) {
			if (!exists(type))
				continue;
			// exec magisk
			allow(type, SEPOL_EXEC_TYPE, "file", "read");
			allow(type, SEPOL_EXEC_TYPE, "file", "open");
			allow(type, SEPOL_EXEC_TYPE, "file", "getattr");
			allow(type, SEPOL_EXEC_TYPE, "file", "execute");
			allow(SEPOL_CLIENT_DOMAIN, type, "process", "sigchld");

			// Auto transit to client domain
			allow(type, SEPOL_CLIENT_DOMAIN, "process", "transition");
			dontaudit(type, SEPOL_CLIENT_DOMAIN, "process", "siginh");
			dontaudit(type, SEPOL_CLIENT_DOMAIN, "process", "rlimitinh");
			dontaudit(type, SEPOL_CLIENT_DOMAIN, "process", "noatsecure");

			// Kill client process
			allow(type, SEPOL_CLIENT_DOMAIN, "process", "signal");
		}

		// type transition require actual types, not attributes
		const char *app_types[] {
			"system_app", "priv_app", "platform_app", "untrusted_app",
			"untrusted_app_25", "untrusted_app_27", "untrusted_app_29" };
		clients.pop_back();
		clients.insert(clients.end(), app_types, app_types + std::size(app_types));
		for (auto type : clients) {
			// Auto transit to client domain
			type_transition(type, SEPOL_EXEC_TYPE, "process", SEPOL_CLIENT_DOMAIN);
		}

		// Allow system_server to manage magisk_client
		allow("system_server", SEPOL_CLIENT_DOMAIN, "process", "getpgid");
		allow("system_server", SEPOL_CLIENT_DOMAIN, "process", "sigkill");

		// Don't allow pesky processes to monitor audit deny logs when poking magisk daemon socket
		dontaudit(ALL, SEPOL_PROC_DOMAIN, "unix_stream_socket", ALL);

		// Only allow client processes to connect to magisk daemon socket
		allow(SEPOL_CLIENT_DOMAIN, SEPOL_PROC_DOMAIN, "unix_stream_socket", ALL);
	} else {
		// Fallback to poking holes in sandbox as Android 4.3 to 7.1 set PR_SET_NO_NEW_PRIVS

		// Allow these processes to access MagiskSU
		const char *clients[] { "init", "shell", "appdomain" };
		for (auto type : clients) {
			if (!exists(type))
				continue;
			allow(type, SEPOL_PROC_DOMAIN, "unix_stream_socket", "connectto");
			allow(type, SEPOL_PROC_DOMAIN, "unix_stream_socket", "getopt");

			// Allow termios ioctl
			const char *pts[] { "devpts", "untrusted_app_devpts" };
			for (auto pts_type : pts) {
				allow(type, pts_type, "chr_file", "ioctl");
				if (db->policyvers >= POLICYDB_VERSION_XPERMS_IOCTL)
					allowxperm(type, pts_type, "chr_file", "0x5400-0x54FF");
			}
		}
	}

	// Let everyone access tmpfs files (for SAR sbin overlay)
	allow(ALL, "tmpfs", "file", ALL);

	// For relabelling files
	allow("rootfs", "labeledfs", "filesystem", "associate");
	allow(SEPOL_FILE_TYPE, "pipefs", "filesystem", "associate");
	allow(SEPOL_FILE_TYPE, "devpts", "filesystem", "associate");

	// Let init transit to SEPOL_PROC_DOMAIN
	allow("kernel", "kernel", "process", "setcurrent");
	allow("kernel", SEPOL_PROC_DOMAIN, "process", "dyntransition");

	// Let init run stuffs
	allow("kernel", SEPOL_PROC_DOMAIN, "fd", "use");
	allow("init", SEPOL_PROC_DOMAIN, "process", ALL);
	allow("init", "tmpfs", "file", "getattr");
	allow("init", "tmpfs", "file", "execute");

	// suRights
	allow("servicemanager", SEPOL_PROC_DOMAIN, "dir", "search");
	allow("servicemanager", SEPOL_PROC_DOMAIN, "dir", "read");
	allow("servicemanager", SEPOL_PROC_DOMAIN, "file", "open");
	allow("servicemanager", SEPOL_PROC_DOMAIN, "file", "read");
	allow("servicemanager", SEPOL_PROC_DOMAIN, "process", "getattr");
	allow("servicemanager", SEPOL_PROC_DOMAIN, "binder", "transfer");
	allow(ALL, SEPOL_PROC_DOMAIN, "process", "sigchld");

	// allowLog
	allow("logd", SEPOL_PROC_DOMAIN, "dir", "search");
	allow("logd", SEPOL_PROC_DOMAIN, "file", "read");
	allow("logd", SEPOL_PROC_DOMAIN, "file", "open");
	allow("logd", SEPOL_PROC_DOMAIN, "file", "getattr");

	// suBackL6
	allow("surfaceflinger", "app_data_file", "dir", ALL);
	allow("surfaceflinger", "app_data_file", "file", ALL);
	allow("surfaceflinger", "app_data_file", "lnk_file", ALL);
	typeattribute("surfaceflinger", "mlstrustedsubject");

	// suMiscL6
	allow("audioserver", "audioserver", "process", "execmem");

	// Liveboot
	allow("surfaceflinger", SEPOL_PROC_DOMAIN, "process", "ptrace");
	allow("surfaceflinger", SEPOL_PROC_DOMAIN, "binder", "transfer");
	allow("surfaceflinger", SEPOL_PROC_DOMAIN, "binder", "call");
	allow("surfaceflinger", SEPOL_PROC_DOMAIN, "fd", "use");
	allow("debuggerd", SEPOL_PROC_DOMAIN, "process", "ptrace");

	// dumpsys
	allow(ALL, SEPOL_PROC_DOMAIN, "fd", "use");
	allow(ALL, SEPOL_PROC_DOMAIN, "fifo_file", "write");
	allow(ALL, SEPOL_PROC_DOMAIN, "fifo_file", "read");
	allow(ALL, SEPOL_PROC_DOMAIN, "fifo_file", "open");
	allow(ALL, SEPOL_PROC_DOMAIN, "fifo_file", "getattr");

	// bootctl
	allow("hwservicemanager", SEPOL_PROC_DOMAIN, "dir", "search");
	allow("hwservicemanager", SEPOL_PROC_DOMAIN, "file", "read");
	allow("hwservicemanager", SEPOL_PROC_DOMAIN, "file", "open");
	allow("hwservicemanager", SEPOL_PROC_DOMAIN, "process", "getattr");
	allow("hwservicemanager", SEPOL_PROC_DOMAIN, "binder", "transfer");

	// For mounting loop devices, mirrors, tmpfs
	allow("kernel", ALL, "file", "read");
	allow("kernel", ALL, "file", "write");

	// Allow all binder transactions
	allow(ALL, SEPOL_PROC_DOMAIN, "binder", ALL);

	// For changing file context
	allow("rootfs", "tmpfs", "filesystem", "associate");

	// Xposed
	allow("untrusted_app", "untrusted_app", "capability", "setgid");
	allow("system_server", "dex2oat_exec", "file", ALL);

	// Support deodexed ROM on Oreo
	allow("zygote", "dalvikcache_data_file", "file", "execute");

	// Support deodexed ROM on Pie (Samsung)
	allow("system_server", "dalvikcache_data_file", "file", "write");
	allow("system_server", "dalvikcache_data_file", "file", "execute");

	// Allow update_engine/addon.d-v2 to run permissive on all ROMs
	permissive("update_engine");

#if 0
	// Remove all dontaudit in debug mode
	impl->strip_dontaudit();
#endif

	log_cb.w = bak;
}