Magisk/native/jni/init/rootdir.cpp
2022-04-02 04:28:30 -07:00

345 lines
10 KiB
C++

#include <sys/mount.h>
#include <libgen.h>
#include <magisk.hpp>
#include <utils.hpp>
#include "init.hpp"
#include "magiskrc.inc"
using namespace std;
static vector<string> rc_list;
static void patch_init_rc(const char *src, const char *dest, const char *tmp_dir) {
FILE *rc = xfopen(dest, "we");
if (!rc) {
PLOGE("%s: open %s failed", __PRETTY_FUNCTION__, src);
return;
}
file_readline(src, [=](string_view line) -> bool {
// Do not start vaultkeeper
if (str_contains(line, "start vaultkeeper")) {
LOGD("Remove vaultkeeper\n");
return true;
}
// Do not run flash_recovery
if (str_starts(line, "service flash_recovery")) {
LOGD("Remove flash_recovery\n");
fprintf(rc, "service flash_recovery /system/bin/xxxxx\n");
return true;
}
// Samsung's persist.sys.zygote.early will start zygotes before actual post-fs-data phase
if (str_starts(line, "on property:persist.sys.zygote.early=")) {
LOGD("Invalidate persist.sys.zygote.early\n");
fprintf(rc, "on property:persist.sys.zygote.early.xxxxx=true\n");
return true;
}
// Else just write the line
fprintf(rc, "%s", line.data());
return true;
});
fprintf(rc, "\n");
// Inject custom rc scripts
for (auto &script : rc_list) {
// Replace template arguments of rc scripts with dynamic paths
replace_all(script, "${MAGISKTMP}", tmp_dir);
fprintf(rc, "\n%s\n", script.data());
}
rc_list.clear();
// Inject Magisk rc scripts
char pfd_svc[16], ls_svc[16], bc_svc[16];
gen_rand_str(pfd_svc, sizeof(pfd_svc));
gen_rand_str(ls_svc, sizeof(ls_svc));
gen_rand_str(bc_svc, sizeof(bc_svc));
LOGD("Inject magisk services: [%s] [%s] [%s]\n", pfd_svc, ls_svc, bc_svc);
fprintf(rc, MAGISK_RC, tmp_dir, pfd_svc, ls_svc, bc_svc);
fclose(rc);
clone_attr(src, dest);
}
static void load_overlay_rc(const char *overlay) {
auto dir = open_dir(overlay);
if (!dir) return;
int dfd = dirfd(dir.get());
// Do not allow overwrite init.rc
unlinkat(dfd, "init.rc", 0);
for (dirent *entry; (entry = xreaddir(dir.get()));) {
if (str_ends(entry->d_name, ".rc")) {
LOGD("Found rc script [%s]\n", entry->d_name);
int rc = xopenat(dfd, entry->d_name, O_RDONLY | O_CLOEXEC);
rc_list.push_back(fd_full_read(rc));
close(rc);
unlinkat(dfd, entry->d_name, 0);
}
}
}
static void recreate_sbin(const char *mirror, bool use_bind_mount) {
auto dp = xopen_dir(mirror);
int src = dirfd(dp.get());
char buf[4096];
for (dirent *entry; (entry = xreaddir(dp.get()));) {
string sbin_path = "/sbin/"s + entry->d_name;
struct stat st;
fstatat(src, entry->d_name, &st, AT_SYMLINK_NOFOLLOW);
if (S_ISLNK(st.st_mode)) {
xreadlinkat(src, entry->d_name, buf, sizeof(buf));
xsymlink(buf, sbin_path.data());
} else {
sprintf(buf, "%s/%s", mirror, entry->d_name);
if (use_bind_mount) {
auto mode = st.st_mode & 0777;
// Create dummy
if (S_ISDIR(st.st_mode))
xmkdir(sbin_path.data(), mode);
else
close(xopen(sbin_path.data(), O_CREAT | O_WRONLY | O_CLOEXEC, mode));
xmount(buf, sbin_path.data(), nullptr, MS_BIND, nullptr);
} else {
xsymlink(buf, sbin_path.data());
}
}
}
}
static string magic_mount_list;
static void magic_mount(const string &sdir, const string &ddir = "") {
auto dir = xopen_dir(sdir.data());
if (!dir) return;
for (dirent *entry; (entry = xreaddir(dir.get()));) {
string src = sdir + "/" + entry->d_name;
string dest = ddir + "/" + entry->d_name;
if (access(dest.data(), F_OK) == 0) {
if (entry->d_type == DT_DIR) {
// Recursive
magic_mount(src, dest);
} else {
LOGD("Mount [%s] -> [%s]\n", src.data(), dest.data());
xmount(src.data(), dest.data(), nullptr, MS_BIND, nullptr);
magic_mount_list += dest;
magic_mount_list += '\n';
}
}
}
}
static void patch_socket_name(const char *path) {
static char rstr[16] = { 0 };
if (rstr[0] == '\0')
gen_rand_str(rstr, sizeof(rstr));
auto bin = mmap_data(path, true);
bin.patch({ make_pair(MAIN_SOCKET, rstr) });
}
void SARBase::backup_files() {
if (access("/overlay.d", F_OK) == 0)
backup_folder("/overlay.d", overlays);
else if (access("/data/overlay.d", F_OK) == 0)
backup_folder("/data/overlay.d", overlays);
self = mmap_data("/proc/self/exe");
if (access("/.backup/.magisk", R_OK) == 0)
magisk_cfg = mmap_data("/.backup/.magisk");
else if (access("/data/.backup/.magisk", R_OK) == 0)
magisk_cfg = mmap_data("/data/.backup/.magisk");
}
#define ROOTMIR MIRRDIR "/system_root"
#define NEW_INITRC "/system/etc/init/hw/init.rc"
void SARBase::patch_ro_root() {
string tmp_dir;
if (access("/sbin", F_OK) == 0) {
tmp_dir = "/sbin";
} else {
char buf[8];
gen_rand_str(buf, sizeof(buf));
tmp_dir = "/dev/"s + buf;
xmkdir(tmp_dir.data(), 0);
}
setup_tmp(tmp_dir.data());
chdir(tmp_dir.data());
// Mount system_root mirror
xmkdir(ROOTMIR, 0755);
xmount("/", ROOTMIR, nullptr, MS_BIND, nullptr);
mount_list.emplace_back(tmp_dir + "/" ROOTMIR);
// Recreate original sbin structure if necessary
if (tmp_dir == "/sbin")
recreate_sbin(ROOTMIR "/sbin", true);
xmkdir(ROOTOVL, 0);
#if ENABLE_AVD_HACK
// Handle avd hack
if (avd_hack) {
int src = xopen("/init", O_RDONLY | O_CLOEXEC);
auto init = mmap_data("/init");
// Force disable early mount on original init
init.patch({ make_pair("android,fstab", "xxx") });
int dest = xopen(ROOTOVL "/init", O_CREAT | O_WRONLY | O_CLOEXEC, 0);
xwrite(dest, init.buf, init.sz);
fclone_attr(src, dest);
close(src);
close(dest);
}
#endif
// Handle overlay.d
restore_folder(ROOTOVL, overlays);
overlays.clear();
load_overlay_rc(ROOTOVL);
if (access(ROOTOVL "/sbin", F_OK) == 0) {
// Move files in overlay.d/sbin into tmp_dir
mv_path(ROOTOVL "/sbin", ".");
}
// Patch init.rc
if (access(NEW_INITRC, F_OK) == 0) {
// Android 11's new init.rc
xmkdirs(dirname(ROOTOVL NEW_INITRC), 0755);
patch_init_rc(NEW_INITRC, ROOTOVL NEW_INITRC, tmp_dir.data());
} else {
patch_init_rc("/init.rc", ROOTOVL "/init.rc", tmp_dir.data());
}
// Extract magisk
{
auto magisk = mmap_data("magisk32.xz");
unlink("magisk32.xz");
int fd = xopen("magisk32", O_WRONLY | O_CREAT, 0755);
unxz(fd, magisk.buf, magisk.sz);
close(fd);
patch_socket_name("magisk32");
if (access("magisk64.xz", F_OK) == 0) {
magisk = mmap_data("magisk64.xz");
unlink("magisk64.xz");
fd = xopen("magisk64", O_WRONLY | O_CREAT, 0755);
unxz(fd, magisk.buf, magisk.sz);
close(fd);
patch_socket_name("magisk64");
xsymlink("./magisk64", "magisk");
} else {
xsymlink("./magisk32", "magisk");
}
}
if ((access(SPLIT_PLAT_CIL, F_OK) != 0 && access("/sepolicy", F_OK) == 0) || !hijack_sepolicy()) {
patch_sepolicy(ROOTOVL "/sepolicy");
}
// Mount rootdir
magic_mount(ROOTOVL);
int dest = xopen(ROOTMNT, O_WRONLY | O_CREAT, 0);
write(dest, magic_mount_list.data(), magic_mount_list.length());
close(dest);
chdir("/");
}
void RootFSInit::prepare() {
self = mmap_data("/init");
magisk_cfg = mmap_data("/.backup/.magisk");
LOGD("Restoring /init\n");
rename(backup_init(), "/init");
}
#define PRE_TMPDIR "/magisk-tmp"
void MagiskInit::patch_rw_root() {
// Create hardlink mirror of /sbin to /root
mkdir("/root", 0777);
clone_attr("/sbin", "/root");
link_path("/sbin", "/root");
// Handle overlays
if (access("/overlay.d", F_OK) == 0) {
LOGD("Merge overlay.d\n");
load_overlay_rc("/overlay.d");
mv_path("/overlay.d", "/");
}
rm_rf("/.backup");
// Patch init.rc
patch_init_rc("/init.rc", "/init.p.rc", "/sbin");
rename("/init.p.rc", "/init.rc");
bool treble;
{
auto init = mmap_data("/init");
treble = init.contains(SPLIT_PLAT_CIL);
}
xmkdir(PRE_TMPDIR, 0);
setup_tmp(PRE_TMPDIR);
chdir(PRE_TMPDIR);
{
// Extract magisk
auto magisk = mmap_data("/sbin/magisk32.xz");
unlink("/sbin/magisk32.xz");
int fd = xopen("magisk32", O_WRONLY | O_CREAT, 0755);
unxz(fd, magisk.buf, magisk.sz);
close(fd);
patch_socket_name("magisk32");
if (access("/sbin/magisk64.xz", F_OK) == 0) {
magisk = mmap_data("/sbin/magisk64.xz");
unlink("/sbin/magisk64.xz");
fd = xopen("magisk64", O_WRONLY | O_CREAT, 0755);
unxz(fd, magisk.buf, magisk.sz);
close(fd);
patch_socket_name("magisk64");
xsymlink("./magisk64", "magisk");
} else {
xsymlink("./magisk32", "magisk");
}
}
if ((!treble && access("/sepolicy", F_OK) == 0) || !hijack_sepolicy()) {
patch_sepolicy("/sepolicy");
}
chdir("/");
// Dump magiskinit as magisk
int fd = xopen("/sbin/magisk", O_WRONLY | O_CREAT, 0755);
write(fd, self.buf, self.sz);
close(fd);
}
int magisk_proxy_main(int argc, char *argv[]) {
setup_klog();
LOGD("%s\n", __FUNCTION__);
// Mount rootfs as rw to do post-init rootfs patches
xmount(nullptr, "/", nullptr, MS_REMOUNT, nullptr);
unlink("/sbin/magisk");
// Move tmpfs to /sbin
// For some reason MS_MOVE won't work, as a workaround bind mount then unmount
xmount(PRE_TMPDIR, "/sbin", nullptr, MS_BIND | MS_REC, nullptr);
xumount2(PRE_TMPDIR, MNT_DETACH);
rmdir(PRE_TMPDIR);
// Create symlinks pointing back to /root
recreate_sbin("/root", false);
// Tell magiskd to remount rootfs
setenv("REMOUNT_ROOT", "1", 1);
execv("/sbin/magisk", argv);
return 1;
}