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Move sbin overlay creation to magiskinit

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This commit is contained in:
topjohnwu 2019-02-09 01:51:46 -05:00
parent 08e3405394
commit c8491d008f
8 changed files with 214 additions and 163 deletions
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121
native/jni/core/bootstages.cpp
View File

@ -632,17 +632,24 @@ void unlock_blocks() {
pthread_exit(nullptr);
}
static const char wrapper[] =
"#!/system/bin/sh\n"
"unset LD_LIBRARY_PATH\n"
"unset LD_PRELOAD\n"
"exec /sbin/magisk.bin \"${0##*/}\" \"$@\"\n";
[[noreturn]] static inline void core_only() {
auto_start_magiskhide();
unblock_boot_process();
}
void post_fs_data(int client) {
// ack
write_int(client, 0);
close(client);
void startup() {
android_logging();
if (!check_data())
unblock_boot_process();
LOGI("** post-fs-data mode running\n");
// Unlock all blocks for rw
unlock_blocks();
if (access(SECURE_DIR, F_OK) != 0) {
/* If the folder is not automatically created by the system,
* do NOT proceed further. Manual creation of the folder
@ -673,106 +680,6 @@ void startup() {
simple_mount("/vendor");
}
// Unlock all blocks for rw
unlock_blocks();
LOGI("* Creating /sbin overlay");
DIR *dir;
struct dirent *entry;
int root, sbin, fd;
void *magisk, *init;
size_t magisk_size, init_size;
xmount(nullptr, "/", nullptr, MS_REMOUNT, nullptr);
// GSIs will have to override /sbin/adbd with /system/bin/adbd
if (access("/sbin/adbd", F_OK) == 0 && access("/system/bin/adbd", F_OK) == 0) {
umount2("/sbin/adbd", MNT_DETACH);
cp_afc("/system/bin/adbd", "/sbin/adbd");
}
// Create hardlink mirror of /sbin to /root
mkdir("/root", 0750);
clone_attr("/sbin", "/root");
full_read("/sbin/magisk", &magisk, &magisk_size);
unlink("/sbin/magisk");
full_read("/sbin/magiskinit", &init, &init_size);
unlink("/sbin/magiskinit");
root = xopen("/root", O_RDONLY | O_CLOEXEC);
sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
link_dir(sbin, root);
close(sbin);
// Mount the /sbin tmpfs overlay
xmount("tmpfs", "/sbin", "tmpfs", 0, nullptr);
chmod("/sbin", 0755);
setfilecon("/sbin", "u:object_r:rootfs:s0");
sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
// Remove some traces of Magisk
unlink(MAGISKRC);
mkdir(MAGISKTMP, 0755);
cp_afc("/.backup/.magisk", MAGISKTMP "/config");
rm_rf("/.backup");
// Create applet symlinks
for (int i = 0; applet_names[i]; ++i) {
snprintf(buf, PATH_MAX, "/sbin/%s", applet_names[i]);
xsymlink("/sbin/magisk", buf);
}
// Setup binary and wrapper
fd = creat("/sbin/magisk.bin", 0755);
xwrite(fd, magisk, magisk_size);
close(fd);
free(magisk);
unlink("/sbin/magisk");
fd = creat("/sbin/magisk", 0755);
xwrite(fd, wrapper, sizeof(wrapper) - 1);
close(fd);
setfilecon("/sbin/magisk.bin", "u:object_r:" SEPOL_FILE_DOMAIN ":s0");
setfilecon("/sbin/magisk", "u:object_r:" SEPOL_FILE_DOMAIN ":s0");
// Setup magiskinit symlinks
fd = creat("/sbin/magiskinit", 0755);
xwrite(fd, init, init_size);
close(fd);
free(init);
setfilecon("/sbin/magiskinit", "u:object_r:" SEPOL_FILE_DOMAIN ":s0");
for (int i = 0; init_applet[i]; ++i) {
snprintf(buf, PATH_MAX, "/sbin/%s", init_applet[i]);
xsymlink("/sbin/magiskinit", buf);
}
// Create symlinks pointing back to /root
dir = xfdopendir(root);
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, sbin, entry->d_name);
}
close(sbin);
close(root);
// Start post-fs-data mode
execl("/sbin/magisk.bin", "magisk", "--post-fs-data", nullptr);
}
[[noreturn]] static inline void core_only() {
auto_start_magiskhide();
unblock_boot_process();
}
void post_fs_data(int client) {
// ack
write_int(client, 0);
close(client);
xmount(nullptr, "/", nullptr, MS_REMOUNT | MS_RDONLY, nullptr);
LOGI("** post-fs-data mode running\n");
if (!magisk_env()) {
LOGE("* Magisk environment setup incomplete, abort\n");
unblock_boot_process();

159
native/jni/core/init.cpp
View File

@ -42,6 +42,7 @@
#include "magiskrc.h"
#include "magisk.h"
#include "magiskpolicy.h"
#include "selinux.h"
#include "utils.h"
#include "flags.h"
@ -49,10 +50,12 @@
int (*init_applet_main[]) (int, char *[]) = { magiskpolicy_main, magiskpolicy_main, nullptr };
static int root = -1;
static bool mnt_system = false;
static bool mnt_vendor = false;
static void *self, *config;
static size_t self_sz, config_sz;
struct cmdline {
bool early_boot;
char slot[3];
@ -344,9 +347,104 @@ static void patch_socket_name(const char *path) {
munmap(buf, size);
}
static void setup_rc() {
// Patch init.rc to load magisk scripts
bool injected = false;
char line[4096];
FILE *fp = xfopen("/init.rc", "r");
int fd = open("/init.rc.new", O_WRONLY | O_CREAT | O_CLOEXEC, 0750);
while(fgets(line, sizeof(line), fp)) {
if (!injected && strncmp(line, "import", 6) == 0) {
if (strstr(line, "init.magisk.rc")) {
injected = true;
} else {
xwrite(fd, "import /init.magisk.rc\n", 23);
injected = true;
}
} else if (strstr(line, "selinux.reload_policy")) {
// Do not allow sepolicy patch
continue;
}
xwrite(fd, line, strlen(line));
}
fclose(fp);
close(fd);
rename("/init.rc.new", "/init.rc");
dump_magiskrc(MAGISKRC, 0750);
}
static const char wrapper[] =
"#!/system/bin/sh\n"
"unset LD_LIBRARY_PATH\n"
"unset LD_PRELOAD\n"
"exec /sbin/magisk.bin \"${0##*/}\" \"$@\"\n";
static void setup_overlay() {
char buf[128];
int fd;
while (access(EARLYINIT, F_OK) != 0)
usleep(10);
selinux_builtin_impl();
setcon("u:r:" SEPOL_PROC_DOMAIN ":s0");
unlink(EARLYINIT);
fd = open("/dev/null", O_RDWR);
xdup2(fd, STDIN_FILENO);
xdup2(fd, STDOUT_FILENO);
xdup2(fd, STDERR_FILENO);
// 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 = open(MAGISKTMP "/config", O_WRONLY | O_CREAT, 0000);
write(fd, config, config_sz);
close(fd);
fd = open("/sbin/magiskinit", O_WRONLY | O_CREAT, 0755);
write(fd, self, self_sz);
close(fd);
fd = open("/sbin/magisk", O_WRONLY | O_CREAT, 0755);
write(fd, wrapper, sizeof(wrapper));
close(fd);
dump_magisk("/sbin/magisk.bin", 0755);
patch_socket_name("/sbin/magisk.bin");
setfilecon("/sbin/magisk", "u:object_r:" SEPOL_FILE_DOMAIN ":s0");
setfilecon("/sbin/magisk.bin", "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(xopen(EARLYINITDONE, O_RDONLY | O_CREAT, 0));
exit(0);
}
static void exec_init(char *argv[]) {
// Clean up
close(root);
umount("/proc");
umount("/sys");
if (mnt_system)
@ -384,8 +482,9 @@ int main(int argc, char *argv[]) {
if (null > STDERR_FILENO)
close(null);
// Backup self
rename("/init", "/init.bak");
// Backup stuffs
full_read("/init", &self, &self_sz);
full_read("/.backup/.magisk", &config, &config_sz);
// Communicate with kernel using procfs and sysfs
mkdir("/proc", 0755);
@ -400,25 +499,24 @@ int main(int argc, char *argv[]) {
* Initialize
* ***********/
int root, sbin;
root = open("/", O_RDONLY | O_CLOEXEC);
if (cmd.early_boot) {
// Clear rootfs
const char *excl[] = { "overlay", ".backup", "proc", "sys", "init.bak", nullptr };
const char *excl[] = { "overlay", "proc", "sys", nullptr };
excl_list = excl;
frm_rf(root);
excl_list = nullptr;
} else {
// Revert original init binary
link("/.backup/init", "/init");
rm_rf("/.backup");
}
// Do not go further if system_root device is booting as recovery
if (!cmd.early_boot && access("/sbin/recovery", F_OK) == 0) {
// Remove Magisk traces
rm_rf("/.backup");
if (!cmd.early_boot && access("/sbin/recovery", F_OK) == 0)
exec_init(argv);
}
/* ************
* Early Mount
@ -467,38 +565,25 @@ int main(int argc, char *argv[]) {
close(fd);
rmdir("/overlay");
}
close(root);
// Patch init.rc to load magisk scripts
bool injected = false;
char line[4096];
FILE *fp = xfopen("/init.rc", "r");
fd = creat("/init.rc.new", 0750);
while(fgets(line, sizeof(line), fp)) {
if (!injected && strncmp(line, "import", 6) == 0) {
if (strstr(line, "init.magisk.rc")) {
injected = true;
} else {
xwrite(fd, "import /init.magisk.rc\n", 23);
injected = true;
}
} else if (strstr(line, "selinux.reload_policy")) {
// Do not allow sepolicy patch
continue;
}
xwrite(fd, line, strlen(line));
}
fclose(fp);
close(fd);
rename("/init.rc.new", "/init.rc");
// Create hardlink mirror of /sbin to /root
mkdir("/root", 0750);
clone_attr("/sbin", "/root");
root = xopen("/root", O_RDONLY | O_CLOEXEC);
sbin = xopen("/sbin", O_RDONLY | O_CLOEXEC);
link_dir(sbin, root);
// Patch sepolicy
setup_rc();
patch_sepolicy();
// Dump binaries
dump_magiskrc(MAGISKRC, 0750);
dump_magisk("/sbin/magisk", 0755);
patch_socket_name("/sbin/magisk");
rename("/init.bak", "/sbin/magiskinit");
// Close all file descriptors
for (int i = 0; i < 30; ++i)
close(i);
// Launch daemon to setup overlay
if (fork_dont_care() == 0)
setup_overlay();
exec_init(argv);
}

5
native/jni/core/magisk.cpp
View File

@ -31,7 +31,7 @@
" --sqlite SQL exec SQL to Magisk database\n"
"\n"
"Supported init triggers:\n"
" startup, post-fs-data, service, boot-complete\n"
" post-fs-data, service, boot-complete\n"
"\n"
"Supported applets:\n");
@ -77,9 +77,6 @@ int magisk_main(int argc, char *argv[]) {
int fd = connect_daemon();
write_int(fd, DO_NOTHING);
return 0;
} else if (strcmp(argv[1], "--startup") == 0) {
startup();
return 0;
} else if (strcmp(argv[1], "--post-fs-data") == 0) {
int fd = connect_daemon();
write_int(fd, POST_FS_DATA);

4
native/jni/include/magisk.h
View File

@ -10,7 +10,9 @@
#define LOG_SOCKET "5864cd77f2f8c59b3882e2d35dbf51e4"
#define JAVA_PACKAGE_NAME "com.topjohnwu.magisk"
#define LOGFILE "/cache/magisk.log"
#define UNBLOCKFILE "/dev/.magisk.unblock"
#define UNBLOCKFILE "/dev/.magisk_unblock"
#define EARLYINIT "/dev/.magisk_early_init"
#define EARLYINITDONE "/dev/.magisk_early_init_done"
#define DISABLEFILE "/cache/.disable_magisk"
#define MAGISKTMP "/sbin/.magisk"
#define BLOCKDIR MAGISKTMP "/block"

8
native/jni/include/magiskrc.h
View File

@ -3,6 +3,12 @@
static const char magiskrc[] =
"on early-init\n"
" write " EARLYINIT " 1\n"
" wait " EARLYINITDONE "\n"
" rm " EARLYINITDONE "\n"
"\n"
"on post-fs-data\n"
" start logd\n"
" load_persist_props\n"
@ -12,7 +18,7 @@ static const char magiskrc[] =
" rm " UNBLOCKFILE "\n"
"\n"
"service %s /sbin/magisk --startup\n"
"service %s /sbin/magisk --post-fs-data\n"
" user root\n"
" seclabel u:r:" SEPOL_PROC_DOMAIN ":s0\n"
" oneshot\n"

4
native/jni/magiskpolicy/rules.cpp
View File

@ -46,6 +46,10 @@ void sepol_magisk_rules() {
sepol_attradd(SEPOL_PROC_DOMAIN, "bluetoothdomain");
sepol_attradd(SEPOL_FILE_DOMAIN, "mlstrustedobject");
// Let init daemon transit context
sepol_allow("kernel", "kernel", "process", "setcurrent");
sepol_allow("kernel", SEPOL_PROC_DOMAIN, "process", "dyntransition");
// Let init run stuffs
sepol_allow("kernel", SEPOL_PROC_DOMAIN, "fd", "use");
sepol_allow("init", SEPOL_PROC_DOMAIN, "process", ALL);

1
native/jni/utils/include/selinux.h
View File

@ -11,6 +11,7 @@ extern int (*lgetfilecon)(const char *path, char ** con);
extern int (*setfilecon)(const char *path, const char * con);
extern int (*lsetfilecon)(const char *path, const char * con);
void selinux_builtin_impl();
void dload_selinux();
void restorecon();

75
native/jni/utils/selinux.cpp
View File

@ -1,6 +1,9 @@
#include <dlfcn.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <syscall.h>
#include <sys/xattr.h>
#include "magisk.h"
#include "utils.h"
@ -11,27 +14,73 @@
#define ADB_CON "u:object_r:adb_data_file:s0"
#define MAGISK_CON "u:object_r:" SEPOL_FILE_DOMAIN ":s0"
// Stub implementations
// Stub implementation
static void v_s(char *s) { delete[] s; }
static int stub(const char *) { return 0; }
static int i_s(const char *) { return 0; }
static int stub(const char *, const char *) { return 0; }
static int i_ss(const char *, const char *) { return 0; }
static int i_ssp(const char *, char ** sp) {
*sp = new char[1]();
static int stub(const char *, char **ctx) {
*ctx = strdup("");
return 0;
}
// Builtin implementation
static void __freecon(char *s) {
free(s);
}
static int __setcon(const char *ctx) {
int fd = open("/proc/self/attr/current", O_WRONLY | O_CLOEXEC);
if (fd < 0)
return fd;
size_t len = strlen(ctx) + 1;
int rc = write(fd, ctx, len);
close(fd);
return rc != len;
}
static int __getfilecon(const char *path, char **ctx) {
char buf[1024];
int rc = syscall(__NR_getxattr, path, XATTR_NAME_SELINUX, buf, sizeof(buf) - 1);
if (rc > 0)
*ctx = strdup(buf);
return rc;
}
static int __lgetfilecon(const char *path, char **ctx) {
char buf[1024];
int rc = syscall(__NR_lgetxattr, path, XATTR_NAME_SELINUX, buf, sizeof(buf) - 1);
if (rc > 0)
*ctx = strdup(buf);
return rc;
}
static int __setfilecon(const char *path, const char *ctx) {
return syscall(__NR_setxattr, path, XATTR_NAME_SELINUX, ctx, strlen(ctx) + 1, 0);
}
static int __lsetfilecon(const char *path, const char *ctx) {
return syscall(__NR_lsetxattr, path, XATTR_NAME_SELINUX, ctx, strlen(ctx) + 1, 0);
}
// Function pointers
void (*freecon)(char *) = v_s;
int (*setcon)(const char *) = i_s;
int (*getfilecon)(const char *, char **) = i_ssp;
int (*lgetfilecon)(const char *, char **) = i_ssp;
int (*setfilecon)(const char *, const char *) = i_ss;
int (*lsetfilecon)(const char *, const char *) = i_ss;
void (*freecon)(char *) = __freecon;
int (*setcon)(const char *) = stub;
int (*getfilecon)(const char *, char **) = stub;
int (*lgetfilecon)(const char *, char **) = stub;
int (*setfilecon)(const char *, const char *) = stub;
int (*lsetfilecon)(const char *, const char *) = stub;
void selinux_builtin_impl() {
setcon = __setcon;
getfilecon = __getfilecon;
lgetfilecon = __lgetfilecon;
setfilecon = __setfilecon;
setfilecon = __lsetfilecon;
}
void dload_selinux() {
void *handle = dlopen("libselinux.so", RTLD_LAZY);