Magisk/activity.c

/*
** Copyright 2017, John Wu (@topjohnwu)
** Copyright 2010, Adam Shanks (@ChainsDD)
** Copyright 2008, Zinx Verituse (@zinxv)
**
*/

#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stdio.h>

#include "magisk.h"
#include "su.h"

/* intent actions */
#define ACTION_REQUEST "%s/" REQUESTOR_PREFIX ".RequestActivity"
#define ACTION_RESULT  "%s/" REQUESTOR_PREFIX ".SuReceiver"

#define AM_PATH "/system/bin/app_process", "/system/bin", "com.android.commands.am.Am"

static char *get_command(const struct su_request *to) {
	if (to->command)
		return to->command;
	if (to->shell)
		return to->shell;
	return DEFAULT_SHELL;
}

static void silent_run(char* const args[]) {
	set_identity(0);
	if (fork())
		return;
	int zero = open("/dev/zero", O_RDONLY | O_CLOEXEC);
	dup2(zero, 0);
	int null = open("/dev/null", O_WRONLY | O_CLOEXEC);
	dup2(null, 1);
	dup2(null, 2);
	setenv("CLASSPATH", "/system/framework/am.jar", 1);
	execv(args[0], args);
	PLOGE("exec am");
	_exit(EXIT_FAILURE);
}

static int setup_user(struct su_context *ctx, char* user) {
	switch (ctx->info->multiuser_mode) {
	case MULTIUSER_MODE_OWNER_ONLY:   /* Should already be denied if not owner */
	case MULTIUSER_MODE_OWNER_MANAGED:
		sprintf(user, "%d", 0);
		return ctx->info->uid / 100000;
	case MULTIUSER_MODE_USER:
		sprintf(user, "%d", ctx->info->uid / 100000);
		break;
	}
	return 0;
}

void app_send_result(struct su_context *ctx, policy_t policy) {
	char fromUid[16];
	if (ctx->info->multiuser_mode == MULTIUSER_MODE_OWNER_MANAGED)
		sprintf(fromUid, "%d", ctx->info->uid % 100000);
	else
		sprintf(fromUid, "%d", ctx->info->uid);

	char toUid[16];
	sprintf(toUid, "%d", ctx->to.uid);

	char pid[16];
	sprintf(pid, "%d", ctx->pid);

	char user[16];
	int notify = setup_user(ctx, user);

	char activity[128];
	sprintf(activity, ACTION_RESULT, ctx->pkg_name);

	// Send notice to manager, enable logging
	char *result_command[] = {
		AM_PATH, "broadcast", "-n",
		activity,
		"--user", user,
		"--ei", "mode", "0",
		"--ei", "from.uid", fromUid,
		"--ei", "to.uid", toUid,
		"--ei", "pid", pid,
		"--es", "command", get_command(&ctx->to),
		"--es", "action", policy == ALLOW ? "allow" : "deny",
		NULL
	};
	silent_run(result_command);

	// Send notice to user (if needed) to create toasts
	if (notify) {
		sprintf(fromUid, "%d", ctx->info->uid);
		sprintf(user, "%d", notify);
		char *notify_command[] = {
			AM_PATH, "broadcast", "-n",
			activity,
			"--user", user,
			"--ei", "mode", "1",
			"--ei", "from.uid", fromUid,
			"--es", "action", policy == ALLOW ? "allow" : "deny",
			NULL
		};
		silent_run(notify_command);
	}
}

void app_send_request(struct su_context *ctx) {
	char user[16];
	int notify = setup_user(ctx, user);

	char activity[128];
	sprintf(activity, ACTION_REQUEST, ctx->pkg_name);

	char *request_command[] = {
		AM_PATH, "start", "-n",
		activity,
		"--user", user,
		"--es", "socket", ctx->sock_path,
		"--ez", "timeout", notify ? "false" : "true",
		NULL
	};
	silent_run(request_command);

	// Send notice to user to tell them root is managed by owner
	if (notify) {
		sprintf(user, "%d", notify);
		sprintf(activity, ACTION_RESULT, ctx->pkg_name);
		char *notify_command[] = {
			AM_PATH, "broadcast", "-n",
			activity,
			"--user", user,
			"--ei", "mode", "2",
			NULL
		};
		silent_run(notify_command);
	}
}