Modularize MagiskInit

This commit is contained in:
topjohnwu 2019-03-15 14:46:30 -04:00
parent f0240b1f06
commit 8893cbd64a

View File

@ -53,19 +53,10 @@
#define DEFAULT_DT_DIR "/proc/device-tree/firmware/android" #define DEFAULT_DT_DIR "/proc/device-tree/firmware/android"
int (*init_applet_main[]) (int, char *[]) = { magiskpolicy_main, magiskpolicy_main, nullptr }; int (*init_applet_main[])(int, char *[]) = { magiskpolicy_main, magiskpolicy_main, nullptr };
static bool mnt_system = false;
static bool mnt_vendor = false;
static bool mnt_product = false;
static bool mnt_odm = false;
static bool kirin = false;
static void *self, *config;
static size_t self_sz, config_sz;
struct cmdline { struct cmdline {
bool early_boot; bool system_as_root;
char slot[3]; char slot[3];
char dt_dir[128]; char dt_dir[128];
}; };
@ -78,192 +69,10 @@ struct device {
char path[64]; char path[64];
}; };
static void parse_cmdline(const std::function<void (std::string_view, const char *)> &fn) { struct raw_data {
char cmdline[4096]; void *buf;
int fd = open("/proc/cmdline", O_RDONLY | O_CLOEXEC); size_t sz;
cmdline[read(fd, cmdline, sizeof(cmdline))] = '\0'; };
close(fd);
char *tok, *eql, *tmp, *saveptr;
saveptr = cmdline;
while ((tok = strtok_r(nullptr, " \n", &saveptr)) != nullptr) {
eql = strchr(tok, '=');
if (eql) {
*eql = '\0';
if (eql[1] == '"') {
tmp = strchr(saveptr, '"');
if (tmp != nullptr) {
*tmp = '\0';
saveptr[-1] = ' ';
saveptr = tmp + 1;
eql++;
}
}
fn(tok, eql + 1);
} else {
fn(tok, "");
}
}
}
static void parse_cmdline(struct cmdline *cmd) {
char cmdline[4096];
int fd = open("/proc/cmdline", O_RDONLY | O_CLOEXEC);
cmdline[read(fd, cmdline, sizeof(cmdline))] = '\0';
close(fd);
bool skip_initramfs = false, enter_recovery = false;
parse_cmdline([&](auto key, auto value) -> void {
LOGD("cmdline: [%s]=[%s]\n", key.data(), value);
if (key == "androidboot.slot_suffix") {
strcpy(cmd->slot, value);
} else if (key == "androidboot.slot") {
cmd->slot[0] = '_';
strcpy(cmd->slot + 1, value);
} else if (key == "skip_initramfs") {
skip_initramfs = true;
} else if (key == "androidboot.android_dt_dir") {
strcpy(cmd->dt_dir, value);
} else if (key == "enter_recovery") {
enter_recovery = value[0] == '1';
} else if (key == "androidboot.hardware") {
kirin = strstr(value, "kirin") || strstr(value, "hi3660");
}
});
if (kirin && enter_recovery) {
// Inform that we are actually booting as recovery
if (FILE *f = fopen("/.backup/.magisk", "ae"); f) {
fprintf(f, "RECOVERYMODE=true\n");
fclose(f);
}
cmd->early_boot = true;
}
cmd->early_boot |= skip_initramfs;
if (cmd->dt_dir[0] == '\0')
strcpy(cmd->dt_dir, DEFAULT_DT_DIR);
LOGD("cmdline: early_boot[%d] slot[%s] dt_dir[%s]\n", cmd->early_boot, cmd->slot, cmd->dt_dir);
}
static void parse_device(struct device *dev, const char *uevent) {
dev->partname[0] = '\0';
FILE *fp = xfopen(uevent, "r");
char buf[64];
while (fgets(buf, sizeof(buf), fp)) {
if (strncmp(buf, "MAJOR", 5) == 0) {
sscanf(buf, "MAJOR=%ld", (long*) &dev->major);
} else if (strncmp(buf, "MINOR", 5) == 0) {
sscanf(buf, "MINOR=%ld", (long*) &dev->minor);
} else if (strncmp(buf, "DEVNAME", 7) == 0) {
sscanf(buf, "DEVNAME=%s", dev->devname);
} else if (strncmp(buf, "PARTNAME", 8) == 0) {
sscanf(buf, "PARTNAME=%s", dev->partname);
}
}
fclose(fp);
LOGD("%s [%s] (%u, %u)\n", dev->devname, dev->partname, (unsigned) dev->major, (unsigned) dev->minor);
}
static bool setup_block(struct device *dev, const char *partname) {
char path[128];
struct dirent *entry;
DIR *dir = opendir("/sys/dev/block");
if (dir == nullptr)
return false;
bool found = false;
while ((entry = readdir(dir))) {
if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue;
sprintf(path, "/sys/dev/block/%s/uevent", entry->d_name);
parse_device(dev, path);
if (strcasecmp(dev->partname, partname) == 0) {
sprintf(dev->path, "/dev/block/%s", dev->devname);
found = true;
break;
}
}
closedir(dir);
if (!found)
return false;
mkdir("/dev", 0755);
mkdir("/dev/block", 0755);
mknod(dev->path, S_IFBLK | 0600, makedev(dev->major, dev->minor));
return true;
}
static inline bool is_lnk(const char *name) {
struct stat st;
if (lstat(name, &st))
return false;
return S_ISLNK(st.st_mode);
}
static bool read_fstab_dt(const struct cmdline *cmd, const char *mnt_point, char *partname, char *partfs) {
char buf[128];
struct stat st;
sprintf(buf, "/%s", mnt_point);
if (is_lnk(buf))
return false;
int fd;
sprintf(buf, "%s/fstab/%s/dev", cmd->dt_dir, mnt_point);
if ((fd = xopen(buf, O_RDONLY | O_CLOEXEC)) >= 0) {
read(fd, buf, sizeof(buf));
close(fd);
char *name = rtrim(strrchr(buf, '/') + 1);
sprintf(partname, "%s%s", name, strend(name, cmd->slot) ? cmd->slot : "");
sprintf(buf, "%s/fstab/%s/type", cmd->dt_dir, mnt_point);
if ((fd = xopen(buf, O_RDONLY | O_CLOEXEC)) >= 0) {
lstat(buf, &st);
read(fd, partfs, st.st_size);
close(fd);
return true;
}
}
return false;
}
static bool patch_sepolicy() {
bool patch_init = false;
if (access(SPLIT_PLAT_CIL, R_OK) == 0)
patch_init = true; /* Split sepolicy */
else if (access("/sepolicy", R_OK) == 0)
load_policydb("/sepolicy"); /* Monolithic sepolicy */
else
return false; /* No SELinux */
// Mount selinuxfs to communicate with kernel
xmount("selinuxfs", SELINUX_MNT, "selinuxfs", 0, nullptr);
if (patch_init)
load_split_cil();
sepol_magisk_rules();
sepol_allow(SEPOL_PROC_DOMAIN, ALL, ALL, ALL);
dump_policydb("/sepolicy");
// Load policy to kernel so we can label rootfs
if (!kirin)
dump_policydb(SELINUX_LOAD);
// Remove OnePlus stupid debug sepolicy and use our own
if (access("/sepolicy_debug", F_OK) == 0) {
unlink("/sepolicy_debug");
link("/sepolicy", "/sepolicy_debug");
}
// Enable selinux functions
selinux_builtin_impl();
return patch_init;
}
static bool unxz(int fd, const uint8_t *buf, size_t size) { static bool unxz(int fd, const uint8_t *buf, size_t size) {
uint8_t out[8192]; uint8_t out[8192];
@ -326,157 +135,116 @@ static int dump_manager(const char *path, mode_t mode) {
return 0; return 0;
} }
static void patch_socket_name(const char *path) { class MagiskInit {
uint8_t *buf; private:
char name[sizeof(MAIN_SOCKET)]; cmdline cmd{};
size_t size; raw_data init{};
mmap_rw(path, buf, size); raw_data config{};
for (int i = 0; i < size; ++i) { int root = -1;
if (memcmp(buf + i, MAIN_SOCKET, sizeof(MAIN_SOCKET)) == 0) { bool mnt_system = false;
gen_rand_str(name, sizeof(name)); bool mnt_vendor = false;
memcpy(buf + i, name, sizeof(name)); bool mnt_product = false;
i += sizeof(name); bool mnt_odm = false;
} bool kirin = false;
if (memcmp(buf + i, LOG_SOCKET, sizeof(LOG_SOCKET)) == 0) { char **argv;
gen_rand_str(name, sizeof(name));
memcpy(buf + i, name, sizeof(name));
i += sizeof(name);
}
}
munmap(buf, size);
}
static void setup_init_rc() { void load_kernel_info();
FILE *rc = xfopen("/init.rc", "ae"); void preset();
char pfd_svc[8], ls_svc[8]; void early_mount();
gen_rand_str(pfd_svc, sizeof(pfd_svc)); void setup_rootfs();
do { bool read_dt_fstab(const char *mnt_point, char *partname, char *partfs);
gen_rand_str(ls_svc, sizeof(ls_svc)); bool patch_sepolicy();
} while (strcmp(pfd_svc, ls_svc) == 0); void cleanup();
fprintf(rc, magiskrc, pfd_svc, pfd_svc, ls_svc);
fclose(rc);
}
static void setup_overlay() { public:
char buf[128]; explicit MagiskInit(char *argv[]) : argv(argv) {}
int fd; void setup_overlay();
void re_exec_init();
void start();
void test();
};
// Wait for early-init start static inline void parse_cmdline(const std::function<void (std::string_view, const char *)> &fn) {
while (access(EARLYINIT, F_OK) != 0) char cmdline[4096];
usleep(10); int fd = open("/proc/cmdline", O_RDONLY | O_CLOEXEC);
setcon("u:r:" SEPOL_PROC_DOMAIN ":s0"); cmdline[read(fd, cmdline, sizeof(cmdline))] = '\0';
unlink(EARLYINIT);
// Mount the /sbin tmpfs overlay
xmount("tmpfs", "/sbin", "tmpfs", 0, nullptr);
chmod("/sbin", 0755);
setfilecon("/sbin", "u:object_r:rootfs:s0");
// Dump binaries
mkdir(MAGISKTMP, 0755);
fd = xopen(MAGISKTMP "/config", O_WRONLY | O_CREAT, 0000);
write(fd, config, config_sz);
close(fd);
fd = xopen("/sbin/magiskinit", O_WRONLY | O_CREAT, 0755);
write(fd, self, self_sz);
close(fd);
dump_magisk("/sbin/magisk", 0755);
patch_socket_name("/sbin/magisk");
setfilecon("/sbin/magisk", "u:object_r:" SEPOL_FILE_DOMAIN ":s0");
setfilecon("/sbin/magiskinit", "u:object_r:" SEPOL_FILE_DOMAIN ":s0");
// Create applet symlinks
for (int i = 0; applet_names[i]; ++i) {
sprintf(buf, "/sbin/%s", applet_names[i]);
xsymlink("/sbin/magisk", buf);
}
for (int i = 0; init_applet[i]; ++i) {
sprintf(buf, "/sbin/%s", init_applet[i]);
xsymlink("/sbin/magiskinit", buf);
}
// Create symlinks pointing back to /root
DIR *dir;
struct dirent *entry;
dir = xopendir("/root");
fd = xopen("/sbin", O_RDONLY);
while((entry = xreaddir(dir))) {
if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0) continue;
snprintf(buf, PATH_MAX, "/root/%s", entry->d_name);
xsymlinkat(buf, fd, entry->d_name);
}
closedir(dir);
close(fd); close(fd);
close(xopen(EARLYINITDONE, O_RDONLY | O_CREAT, 0)); char *tok, *eql, *tmp, *saveptr;
exit(0); saveptr = cmdline;
while ((tok = strtok_r(nullptr, " \n", &saveptr)) != nullptr) {
eql = strchr(tok, '=');
if (eql) {
*eql = '\0';
if (eql[1] == '"') {
tmp = strchr(saveptr, '"');
if (tmp != nullptr) {
*tmp = '\0';
saveptr[-1] = ' ';
saveptr = tmp + 1;
eql++;
}
}
fn(tok, eql + 1);
} else {
fn(tok, "");
}
}
} }
[[noreturn]] static void exec_init(char *argv[]) { void MagiskInit::load_kernel_info() {
// Clean up
umount(SELINUX_MNT);
umount("/sys");
umount("/proc");
if (mnt_system)
umount("/system");
if (mnt_vendor)
umount("/vendor");
if (mnt_product)
umount("/product");
if (mnt_odm)
umount("/odm");
execv("/init", argv);
exit(1);
}
int main(int argc, char *argv[]) {
umask(0);
no_logging();
for (int i = 0; init_applet[i]; ++i) {
if (strcmp(basename(argv[0]), init_applet[i]) == 0)
return (*init_applet_main[i])(argc, argv);
}
if (argc > 1 && strcmp(argv[1], "-x") == 0) {
if (strcmp(argv[2], "magisk") == 0)
return dump_magisk(argv[3], 0755);
else if (strcmp(argv[2], "manager") == 0)
return dump_manager(argv[3], 0644);
}
// Prevent file descriptor confusion
mknod("/null", S_IFCHR | 0666, makedev(1, 3));
int null = open("/null", O_RDWR | O_CLOEXEC);
unlink("/null");
xdup3(null, STDIN_FILENO, O_CLOEXEC);
xdup3(null, STDOUT_FILENO, O_CLOEXEC);
xdup3(null, STDERR_FILENO, O_CLOEXEC);
if (null > STDERR_FILENO)
close(null);
// Communicate with kernel using procfs and sysfs // Communicate with kernel using procfs and sysfs
mkdir("/proc", 0755); mkdir("/proc", 0755);
xmount("proc", "/proc", "proc", 0, nullptr); xmount("proc", "/proc", "proc", 0, nullptr);
mkdir("/sys", 0755); mkdir("/sys", 0755);
xmount("sysfs", "/sys", "sysfs", 0, nullptr); xmount("sysfs", "/sys", "sysfs", 0, nullptr);
struct cmdline cmd{}; char cmdline[4096];
parse_cmdline(&cmd); int fd = open("/proc/cmdline", O_RDONLY | O_CLOEXEC);
cmdline[read(fd, cmdline, sizeof(cmdline))] = '\0';
close(fd);
// Backup stuffs bool skip_initramfs = false, enter_recovery = false;
full_read("/init", &self, &self_sz);
full_read("/.backup/.magisk", &config, &config_sz);
/************* parse_cmdline([&](auto key, auto value) -> void {
* Initialize LOGD("cmdline: [%s]=[%s]\n", key.data(), value);
*************/ if (key == "androidboot.slot_suffix") {
strcpy(cmd.slot, value);
} else if (key == "androidboot.slot") {
cmd.slot[0] = '_';
strcpy(cmd.slot + 1, value);
} else if (key == "skip_initramfs") {
skip_initramfs = true;
} else if (key == "androidboot.android_dt_dir") {
strcpy(cmd.dt_dir, value);
} else if (key == "enter_recovery") {
enter_recovery = value[0] == '1';
} else if (key == "androidboot.hardware") {
kirin = strstr(value, "kirin") || strstr(value, "hi3660");
}
});
int root, sbin; if (kirin && enter_recovery) {
// Inform that we are actually booting as recovery
if (FILE *f = fopen("/.backup/.magisk", "ae"); f) {
fprintf(f, "RECOVERYMODE=true\n");
fclose(f);
}
cmd.system_as_root = true;
}
cmd.system_as_root |= skip_initramfs;
if (cmd.dt_dir[0] == '\0')
strcpy(cmd.dt_dir, DEFAULT_DT_DIR);
LOGD("system_as_root[%d] slot[%s] dt_dir[%s]\n", cmd.system_as_root, cmd.slot, cmd.dt_dir);
}
void MagiskInit::preset() {
root = open("/", O_RDONLY | O_CLOEXEC); root = open("/", O_RDONLY | O_CLOEXEC);
if (cmd.early_boot) { if (cmd.system_as_root) {
// Clear rootfs // Clear rootfs
const char *excl[] = { "overlay", "proc", "sys", nullptr }; const char *excl[] = { "overlay", "proc", "sys", nullptr };
excl_list = excl; excl_list = excl;
@ -491,18 +259,83 @@ int main(int argc, char *argv[]) {
// Do not go further if device is booting into recovery // Do not go further if device is booting into recovery
if (access("/sbin/recovery", F_OK) == 0) if (access("/sbin/recovery", F_OK) == 0)
exec_init(argv); re_exec_init();
} }
}
/************** static inline void parse_device(struct device *dev, const char *uevent) {
* Early Mount dev->partname[0] = '\0';
**************/ FILE *fp = xfopen(uevent, "r");
char buf[64];
while (fgets(buf, sizeof(buf), fp)) {
if (strncmp(buf, "MAJOR", 5) == 0) {
sscanf(buf, "MAJOR=%ld", (long*) &dev->major);
} else if (strncmp(buf, "MINOR", 5) == 0) {
sscanf(buf, "MINOR=%ld", (long*) &dev->minor);
} else if (strncmp(buf, "DEVNAME", 7) == 0) {
sscanf(buf, "DEVNAME=%s", dev->devname);
} else if (strncmp(buf, "PARTNAME", 8) == 0) {
sscanf(buf, "PARTNAME=%s", dev->partname);
}
}
fclose(fp);
LOGD("%s [%s] (%u, %u)\n", dev->devname, dev->partname, (unsigned) dev->major, (unsigned) dev->minor);
}
static bool setup_block(struct device *dev, const char *partname) {
char path[128];
struct dirent *entry;
DIR *dir = opendir("/sys/dev/block");
if (dir == nullptr)
return false;
bool found = false;
while ((entry = readdir(dir))) {
if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue;
sprintf(path, "/sys/dev/block/%s/uevent", entry->d_name);
parse_device(dev, path);
if (strcasecmp(dev->partname, partname) == 0) {
sprintf(dev->path, "/dev/block/%s", dev->devname);
found = true;
break;
}
}
closedir(dir);
if (!found)
return false;
mkdir("/dev", 0755);
mkdir("/dev/block", 0755);
mknod(dev->path, S_IFBLK | 0600, makedev(dev->major, dev->minor));
return true;
}
static inline bool is_lnk(const char *name) {
struct stat st;
if (lstat(name, &st))
return false;
return S_ISLNK(st.st_mode);
}
#define link_root(part) \
if (is_lnk("/system_root" part)) \
cp_afc("/system_root" part, part)
#define mount_root(part) \
if (!is_lnk("/" #part) && read_dt_fstab(#part, partname, fstype)) { \
setup_block(&dev, partname); \
xmkdir("/" #part, 0755); \
xmount(dev.path, "/" #part, fstype, MS_RDONLY, nullptr); \
mnt_##part = true; \
}
void MagiskInit::early_mount() {
struct device dev; struct device dev;
char partname[32]; char partname[32];
char partfs[32]; char fstype[32];
if (cmd.early_boot) { if (cmd.system_as_root) {
sprintf(partname, "system%s", cmd.slot); sprintf(partname, "system%s", cmd.slot);
setup_block(&dev, partname); setup_block(&dev, partname);
xmkdir("/system_root", 0755); xmkdir("/system_root", 0755);
@ -511,47 +344,22 @@ int main(int argc, char *argv[]) {
xmount("/system_root/system", "/system", nullptr, MS_BIND, nullptr); xmount("/system_root/system", "/system", nullptr, MS_BIND, nullptr);
// Copy if these partitions are symlinks // Copy if these partitions are symlinks
if (is_lnk("/system_root/vendor")) link_root("/vendor");
cp_afc("/system_root/vendor", "/vendor"); link_root("/product");
if (is_lnk("/system_root/product")) link_root("/odm");
cp_afc("/system_root/product", "/product"); } else {
if (is_lnk("/system_root/odm")) mount_root(system);
cp_afc("/system_root/odm", "/odm");
} else if (read_fstab_dt(&cmd, "system", partname, partfs)) {
setup_block(&dev, partname);
xmount(dev.path, "/system", partfs, MS_RDONLY, nullptr);
mnt_system = true;
} }
if (read_fstab_dt(&cmd, "vendor", partname, partfs)) { mount_root(vendor);
setup_block(&dev, partname); mount_root(product);
xmkdir("/vendor", 0755); mount_root(odm);
xmount(dev.path, "/vendor", partfs, MS_RDONLY, nullptr); }
mnt_vendor = true;
}
if (read_fstab_dt(&cmd, "product", partname, partfs)) {
setup_block(&dev, partname);
xmkdir("/product", 0755);
xmount(dev.path, "/product", partfs, MS_RDONLY, nullptr);
mnt_product = true;
}
if (read_fstab_dt(&cmd, "odm", partname, partfs)) {
setup_block(&dev, partname);
xmkdir("/odm", 0755);
xmount(dev.path, "/odm", partfs, MS_RDONLY, nullptr);
mnt_odm = true;
}
/***************
* Setup Rootfs
***************/
void MagiskInit::setup_rootfs() {
bool patch_init = patch_sepolicy(); bool patch_init = patch_sepolicy();
if (cmd.early_boot) { if (cmd.system_as_root) {
// Clone rootfs except /system // Clone rootfs except /system
int system_root = open("/system_root", O_RDONLY | O_CLOEXEC); int system_root = open("/system_root", O_RDONLY | O_CLOEXEC);
const char *excl[] = { "system", nullptr }; const char *excl[] = { "system", nullptr };
@ -594,7 +402,15 @@ int main(int argc, char *argv[]) {
rmdir("/overlay"); rmdir("/overlay");
} }
setup_init_rc(); // Patch init.rc
FILE *rc = xfopen("/init.rc", "ae");
char pfd_svc[8], ls_svc[8];
gen_rand_str(pfd_svc, sizeof(pfd_svc));
do {
gen_rand_str(ls_svc, sizeof(ls_svc));
} while (strcmp(pfd_svc, ls_svc) == 0);
fprintf(rc, magiskrc, pfd_svc, pfd_svc, ls_svc);
fclose(rc);
// Don't let init run in init yet // Don't let init run in init yet
lsetfilecon("/init", "u:object_r:rootfs:s0"); lsetfilecon("/init", "u:object_r:rootfs:s0");
@ -602,9 +418,215 @@ int main(int argc, char *argv[]) {
// Create hardlink mirror of /sbin to /root // Create hardlink mirror of /sbin to /root
mkdir("/root", 0750); mkdir("/root", 0750);
clone_attr("/sbin", "/root"); clone_attr("/sbin", "/root");
root = xopen("/root", O_RDONLY | O_CLOEXEC); int rootdir = xopen("/root", O_RDONLY | O_CLOEXEC);
sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC); int sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
link_dir(sbin, root); link_dir(sbin, rootdir);
}
bool MagiskInit::patch_sepolicy() {
bool patch_init = false;
if (access(SPLIT_PLAT_CIL, R_OK) == 0)
patch_init = true; /* Split sepolicy */
else if (access("/sepolicy", R_OK) == 0)
load_policydb("/sepolicy"); /* Monolithic sepolicy */
else
return false; /* No SELinux */
// Mount selinuxfs to communicate with kernel
xmount("selinuxfs", SELINUX_MNT, "selinuxfs", 0, nullptr);
if (patch_init)
load_split_cil();
sepol_magisk_rules();
sepol_allow(SEPOL_PROC_DOMAIN, ALL, ALL, ALL);
dump_policydb("/sepolicy");
// Load policy to kernel so we can label rootfs
if (!kirin)
dump_policydb(SELINUX_LOAD);
// Remove OnePlus stupid debug sepolicy and use our own
if (access("/sepolicy_debug", F_OK) == 0) {
unlink("/sepolicy_debug");
link("/sepolicy", "/sepolicy_debug");
}
// Enable selinux functions
selinux_builtin_impl();
return patch_init;
}
bool MagiskInit::read_dt_fstab(const char *mnt_point, char *partname, char *partfs) {
char path[128];
int fd;
sprintf(path, "%s/fstab/%s/dev", cmd.dt_dir, mnt_point);
if ((fd = xopen(path, O_RDONLY | O_CLOEXEC)) >= 0) {
read(fd, path, sizeof(path));
close(fd);
char *name = rtrim(strrchr(path, '/') + 1);
sprintf(partname, "%s%s", name, strend(name, cmd.slot) ? cmd.slot : "");
sprintf(path, "%s/fstab/%s/type", cmd.dt_dir, mnt_point);
if ((fd = xopen(path, O_RDONLY | O_CLOEXEC)) >= 0) {
read(fd, partfs, 32);
close(fd);
return true;
}
}
return false;
}
#define umount_part(part) \
if (mnt_##part) \
umount("/" #part);
void MagiskInit::cleanup() {
umount(SELINUX_MNT);
umount("/sys");
umount("/proc");
umount_part(system);
umount_part(vendor);
umount_part(product);
umount_part(odm);
}
static inline void patch_socket_name(const char *path) {
uint8_t *buf;
char name[sizeof(MAIN_SOCKET)];
size_t size;
mmap_rw(path, buf, size);
for (int i = 0; i < size; ++i) {
if (memcmp(buf + i, MAIN_SOCKET, sizeof(MAIN_SOCKET)) == 0) {
gen_rand_str(name, sizeof(name));
memcpy(buf + i, name, sizeof(name));
i += sizeof(name);
}
if (memcmp(buf + i, LOG_SOCKET, sizeof(LOG_SOCKET)) == 0) {
gen_rand_str(name, sizeof(name));
memcpy(buf + i, name, sizeof(name));
i += sizeof(name);
}
}
munmap(buf, size);
}
void MagiskInit::setup_overlay() {
char path[128];
int fd;
// Wait for early-init start
while (access(EARLYINIT, F_OK) != 0)
usleep(10);
setcon("u:r:" SEPOL_PROC_DOMAIN ":s0");
unlink(EARLYINIT);
// Mount the /sbin tmpfs overlay
xmount("tmpfs", "/sbin", "tmpfs", 0, nullptr);
chmod("/sbin", 0755);
setfilecon("/sbin", "u:object_r:rootfs:s0");
// Dump binaries
mkdir(MAGISKTMP, 0755);
fd = xopen(MAGISKTMP "/config", O_WRONLY | O_CREAT, 0000);
write(fd, config.buf, config.sz);
close(fd);
fd = xopen("/sbin/magiskinit", O_WRONLY | O_CREAT, 0755);
write(fd, init.buf, init.sz);
close(fd);
dump_magisk("/sbin/magisk", 0755);
patch_socket_name("/sbin/magisk");
setfilecon("/sbin/magisk", "u:object_r:" SEPOL_FILE_DOMAIN ":s0");
setfilecon("/sbin/magiskinit", "u:object_r:" SEPOL_FILE_DOMAIN ":s0");
// Create applet symlinks
for (int i = 0; applet_names[i]; ++i) {
sprintf(path, "/sbin/%s", applet_names[i]);
xsymlink("/sbin/magisk", path);
}
for (int i = 0; init_applet[i]; ++i) {
sprintf(path, "/sbin/%s", init_applet[i]);
xsymlink("/sbin/magiskinit", path);
}
// Create symlinks pointing back to /root
DIR *dir = xopendir("/root");
struct dirent *entry;
fd = xopen("/sbin", O_RDONLY);
while((entry = xreaddir(dir))) {
if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue;
snprintf(path, PATH_MAX, "/root/%s", entry->d_name);
xsymlinkat(path, fd, entry->d_name);
}
closedir(dir);
close(fd);
close(xopen(EARLYINITDONE, O_RDONLY | O_CREAT, 0));
exit(0);
}
void MagiskInit::re_exec_init() {
cleanup();
execv("/init", argv);
exit(1);
}
void MagiskInit::start() {
// Prevent file descriptor confusion
mknod("/null", S_IFCHR | 0666, makedev(1, 3));
int null = open("/null", O_RDWR | O_CLOEXEC);
unlink("/null");
xdup3(null, STDIN_FILENO, O_CLOEXEC);
xdup3(null, STDOUT_FILENO, O_CLOEXEC);
xdup3(null, STDERR_FILENO, O_CLOEXEC);
if (null > STDERR_FILENO)
close(null);
full_read("/init", &init.buf, &init.sz);
full_read("/.backup/.magisk", &config.buf, &config.sz);
load_kernel_info();
preset();
early_mount();
setup_rootfs();
}
void MagiskInit::test() {
cmdline_logging();
log_cb.ex = nop_ex;
chdir(argv[1]);
chroot(".");
chdir("/");
load_kernel_info();
preset();
early_mount();
setup_rootfs();
cleanup();
}
int main(int argc, char *argv[]) {
umask(0);
for (int i = 0; init_applet[i]; ++i) {
if (strcmp(basename(argv[0]), init_applet[i]) == 0)
return (*init_applet_main[i])(argc, argv);
}
if (argc > 1 && strcmp(argv[1], "-x") == 0) {
if (strcmp(argv[2], "magisk") == 0)
return dump_magisk(argv[3], 0755);
else if (strcmp(argv[2], "manager") == 0)
return dump_manager(argv[3], 0644);
}
MagiskInit init(argv);
// Run the main routine
init.start();
// Close all file descriptors // Close all file descriptors
for (int i = 0; i < 30; ++i) for (int i = 0; i < 30; ++i)
@ -612,7 +634,7 @@ int main(int argc, char *argv[]) {
// Launch daemon to setup overlay // Launch daemon to setup overlay
if (fork_dont_care() == 0) if (fork_dont_care() == 0)
setup_overlay(); init.setup_overlay();
exec_init(argv); init.re_exec_init();
} }