MarcoBuster/Magisk
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Delay mounting sbin overlay

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This commit is contained in:
topjohnwu 2019-06-22 03:14:33 -07:00
parent 120bd6cd68
commit cfec0db947
5 changed files with 131 additions and 75 deletions
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3
native/jni/core/bootstages.cpp
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@ -560,6 +560,9 @@ void post_fs_data(int client) {
write_int(client, 0);
close(client);
if (getenv("REMOUNT_ROOT"))
xmount(nullptr, "/", nullptr, MS_REMOUNT | MS_RDONLY, nullptr);
if (!check_data())
unblock_boot_process();

7
native/jni/init/early_mount.cpp
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@ -74,7 +74,7 @@ static void setup_block(const char *partname, char *block_dev) {
}
}
bool BaseInit::read_dt_fstab(const char *name, char *partname, char *fstype) {
bool MagiskInit::read_dt_fstab(const char *name, char *partname, char *fstype) {
char path[128];
int fd;
sprintf(path, "%s/fstab/%s/dev", cmd->dt_dir, name);
@ -152,10 +152,9 @@ void SARInit::early_mount() {
if (mnt_##name) \
umount("/" #name);
void BaseInit::cleanup() {
void MagiskInit::cleanup() {
BaseInit::cleanup();
umount(SELINUX_MNT);
umount("/sys");
umount("/proc");
umount_root(system);
umount_root(vendor);
umount_root(product);

26
native/jni/init/init.cpp
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@ -26,13 +26,17 @@
using namespace std;
constexpr const char *init_applet[] =
{ "magiskpolicy", "supolicy", "magisk", nullptr };
constexpr int (*init_applet_main[])(int, char *[]) =
{ magiskpolicy_main, magiskpolicy_main, magisk_proxy_main, nullptr };
#ifdef MAGISK_DEBUG
static FILE *kmsg;
static int vprintk(const char *fmt, va_list ap) {
fprintf(kmsg, "magiskinit: ");
return vfprintf(kmsg, fmt, ap);
}
static void setup_klog() {
mknod("/kmsg", S_IFCHR | 0666, makedev(1, 11));
int fd = xopen("/kmsg", O_WRONLY | O_CLOEXEC);
@ -46,11 +50,6 @@ static void setup_klog() {
#define setup_klog(...)
#endif
constexpr const char *init_applet[] =
{ "magiskpolicy", "supolicy", nullptr };
constexpr int (*init_applet_main[])(int, char *[]) =
{ magiskpolicy_main, magiskpolicy_main, nullptr };
static bool unxz(int fd, const uint8_t *buf, size_t size) {
uint8_t out[8192];
xz_crc32_init();
@ -113,6 +112,11 @@ static int dump_manager(const char *path, mode_t mode) {
return 0;
}
void BaseInit::cleanup() {
umount("/sys");
umount("/proc");
}
void BaseInit::re_exec_init() {
LOGD("Re-exec /init\n");
cleanup();
@ -121,19 +125,22 @@ void BaseInit::re_exec_init() {
}
void LegacyInit::preset() {
full_read("/init", &self.buf, &self.sz);
LOGD("Reverting /init\n");
root = open("/", O_RDONLY | O_CLOEXEC);
rename("/.backup/init", "/init");
rm_rf("/.backup");
}
void SARInit::preset() {
full_read("/init", &self.buf, &self.sz);
LOGD("Cleaning rootfs\n");
root = open("/", O_RDONLY | O_CLOEXEC);
frm_rf(root, { "overlay", "proc", "sys" });
}
void BaseInit::start() {
void MagiskInit::start() {
// Prevent file descriptor confusion
mknod("/null", S_IFCHR | 0666, makedev(1, 3));
int null = open("/null", O_RDWR | O_CLOEXEC);
@ -144,9 +151,6 @@ void BaseInit::start() {
if (null > STDERR_FILENO)
close(null);
full_read("/init", &self.buf, &self.sz);
full_read("/.backup/.magisk", &config.buf, &config.sz);
preset();
early_mount();
setup_rootfs();

35
native/jni/init/init.h
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@ -14,9 +14,18 @@ struct raw_data {
class BaseInit {
protected:
cmdline *cmd;
raw_data self{};
raw_data config{};
char **argv;
void re_exec_init();
virtual void cleanup();
public:
BaseInit(char *argv[], cmdline *cmd) : cmd(cmd), argv(argv) {}
virtual ~BaseInit() = default;
virtual void start() = 0;
};
class MagiskInit : public BaseInit {
protected:
raw_data self{};
int root = -1;
bool load_sepol = false;
bool mnt_system = false;
@ -24,34 +33,31 @@ protected:
bool mnt_product = false;
bool mnt_odm = false;
virtual void preset() {};
virtual void early_mount() {}
virtual void preset() = 0;
virtual void early_mount() = 0;
void setup_rootfs();
bool read_dt_fstab(const char *name, char *partname, char *fstype);
bool patch_sepolicy();
void cleanup();
void re_exec_init();
void cleanup() override;
public:
BaseInit(char *argv[], cmdline *cmd) : cmd(cmd), argv(argv) {}
virtual ~BaseInit() = default;
virtual void start();
MagiskInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
void start() override;
};
class LegacyInit : public BaseInit {
class LegacyInit : public MagiskInit {
protected:
void preset() override;
void early_mount() override;
public:
LegacyInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
LegacyInit(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd) {};
};
class SARInit : public BaseInit {
class SARInit : public MagiskInit {
protected:
void preset() override;
void early_mount() override;
public:
SARInit(char *argv[], cmdline *cmd) : BaseInit(argv, cmd) {};
SARInit(char *argv[], cmdline *cmd) : MagiskInit(argv, cmd) {};
};
static inline bool is_lnk(const char *name) {
@ -63,3 +69,4 @@ static inline bool is_lnk(const char *name) {
void load_kernel_info(cmdline *cmd);
int dump_magisk(const char *path, mode_t mode);
int magisk_proxy_main(int argc, char *argv[]);

135
native/jni/init/rootfs.cpp
View File

@ -1,11 +1,13 @@
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <fcntl.h>
#include <magisk.h>
#include <utils.h>
#include "init.h"
#include "flags.h"
#include "magiskrc.h"
#ifdef USE_64BIT
@ -37,7 +39,7 @@ constexpr const char wrapper[] =
"exec /sbin/magisk.bin \"$0\" \"$@\"\n"
;
void BaseInit::setup_rootfs() {
void MagiskInit::setup_rootfs() {
bool patch_init = patch_sepolicy();
if (cmd->system_as_root) {
@ -125,55 +127,13 @@ void BaseInit::setup_rootfs() {
link_dir(sbin, rootdir);
close(sbin);
LOGD("Mount /sbin tmpfs overlay\n");
xmount("tmpfs", "/sbin", "tmpfs", 0, "mode=755");
sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
char path[64];
// Create symlinks pointing back to /root
DIR *dir = xfdopendir(rootdir);
struct dirent *entry;
while((entry = xreaddir(dir))) {
if (entry->d_name == "."sv || entry->d_name == ".."sv)
continue;
sprintf(path, "/root/%s", entry->d_name);
xsymlinkat(path, sbin, entry->d_name);
}
// 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);
// Dump magiskinit as magisk
fd = xopen("/sbin/magisk", O_WRONLY | O_CREAT, 0755);
write(fd, self.buf, self.sz);
close(fd);
if (access("/system/apex", F_OK) == 0) {
LOGD("APEX detected, use wrapper\n");
dump_magisk("/sbin/magisk.bin", 0755);
patch_socket_name("/sbin/magisk.bin");
fd = xopen("/sbin/magisk", O_WRONLY | O_CREAT, 0755);
write(fd, wrapper, sizeof(wrapper) - 1);
close(fd);
} else {
dump_magisk("/sbin/magisk", 0755);
patch_socket_name("/sbin/magisk");
}
// Create applet symlinks
for (int i = 0; applet_names[i]; ++i) {
sprintf(path, "/sbin/%s", applet_names[i]);
xsymlink("/sbin/magisk", path);
}
xsymlink("/sbin/magiskinit", "/sbin/magiskpolicy");
xsymlink("/sbin/magiskinit", "/sbin/supolicy");
close(rootdir);
close(sbin);
}
bool BaseInit::patch_sepolicy() {
bool MagiskInit::patch_sepolicy() {
bool patch_init = false;
if (access(SPLIT_PLAT_CIL, R_OK) == 0) {
@ -214,3 +174,86 @@ bool BaseInit::patch_sepolicy() {
return patch_init;
}
#ifdef MAGISK_DEBUG
static FILE *kmsg;
static int vprintk(const char *fmt, va_list ap) {
fprintf(kmsg, "magiskinit: ");
return vfprintf(kmsg, fmt, ap);
}
static void setup_klog() {
int fd = xopen("/proc/kmsg", O_WRONLY | O_CLOEXEC);
kmsg = fdopen(fd, "w");
setbuf(kmsg, nullptr);
log_cb.d = log_cb.i = log_cb.w = log_cb.e = vprintk;
log_cb.ex = nop_ex;
}
#else
#define setup_klog(...)
#endif
int magisk_proxy_main(int argc, char *argv[]) {
setup_klog();
raw_data config;
raw_data self;
full_read("/sbin/magisk", &self.buf, &self.sz);
full_read("/.backup/.magisk", &config.buf, &config.sz);
xmount(nullptr, "/", nullptr, MS_REMOUNT, nullptr);
unlink("/sbin/magisk");
rm_rf("/.backup");
LOGD("Mount /sbin tmpfs overlay\n");
xmount("tmpfs", "/sbin", "tmpfs", 0, "mode=755");
int sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
char path[64];
// Create symlinks pointing back to /root
{
unique_ptr<DIR, decltype(&closedir)> dir(xopendir("/root"), &closedir);
struct dirent *entry;
while((entry = xreaddir(dir.get()))) {
if (entry->d_name == "."sv || entry->d_name == ".."sv)
continue;
sprintf(path, "/root/%s", entry->d_name);
xsymlinkat(path, sbin, entry->d_name);
}
}
// Dump binaries
mkdir(MAGISKTMP, 0755);
int 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, self.buf, self.sz);
close(fd);
if (access("/system/apex", F_OK) == 0) {
LOGD("APEX detected, use wrapper\n");
dump_magisk("/sbin/magisk.bin", 0755);
patch_socket_name("/sbin/magisk.bin");
fd = xopen("/sbin/magisk", O_WRONLY | O_CREAT, 0755);
write(fd, wrapper, sizeof(wrapper) - 1);
close(fd);
} else {
dump_magisk("/sbin/magisk", 0755);
patch_socket_name("/sbin/magisk");
}
// Create applet symlinks
for (int i = 0; applet_names[i]; ++i) {
sprintf(path, "/sbin/%s", applet_names[i]);
xsymlink("/sbin/magisk", path);
}
xsymlink("/sbin/magiskinit", "/sbin/magiskpolicy");
xsymlink("/sbin/magiskinit", "/sbin/supolicy");
setenv("REMOUNT_ROOT", "1", 1);
execv("/sbin/magisk", argv);
return 1;
}