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MagiskHide refactor

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This commit is contained in:
topjohnwu 2017-07-10 23:39:33 +08:00
parent cccb5a3e08
commit 504a9b4746
5 changed files with 124 additions and 189 deletions
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1
jni/Android.mk
View File

@ -25,7 +25,6 @@ LOCAL_SRC_FILES := \
daemon/log_monitor.c \
daemon/bootstages.c \
magiskhide/magiskhide.c \
magiskhide/hide_daemon.c \
magiskhide/proc_monitor.c \
magiskhide/hide_utils.c \
magiskpolicy/magiskpolicy.c \

129
jni/magiskhide/hide_daemon.c
View File

@ -1,129 +0,0 @@
/* hide_daemon.c - MagiskHide daemon
*
* A dedicated process to join the target namespace,
* and hide all traces in that particular namespace
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include "magisk.h"
#include "utils.h"
#include "magiskhide.h"
static int pid;
static void lazy_unmount(const char* mountpoint) {
if (umount2(mountpoint, MNT_DETACH) != -1)
LOGI("hide_daemon: Unmounted (%s)\n", mountpoint);
else
LOGI("hide_daemon: Unmount Failed (%s)\n", mountpoint);
}
static void hide_daemon_err() {
LOGD("hide_daemon: error occured, stopping magiskhide services\n");
// Resume process if possible
kill(pid, SIGCONT);
int err = 1;
write(sv[1], &err, sizeof(err));
_exit(-1);
}
int hide_daemon() {
// Fork to a new process
hide_pid = fork();
switch(hide_pid) {
case -1:
PLOGE("fork");
return 1;
case 0:
break;
default:
return 0;
}
close(sv[0]);
// Set the process name
strcpy(argv0, "magiskhide_daemon");
LOGD("hide_daemon: listening for hide requests");
// When an error occurs, report its failure to main process
err_handler = hide_daemon_err;
char buffer[4096], cache_block[256], *line;
struct vector mount_list;
cache_block[0] = '\0';
while(1) {
xxread(sv[1], &pid, sizeof(pid));
// Termination called
if(pid == -1) {
LOGD("hide_daemon: received termination request\n");
_exit(0);
}
manage_selinux();
relink_sbin();
if (switch_mnt_ns(pid))
continue;
snprintf(buffer, sizeof(buffer), "/proc/%d/mounts", pid);
vec_init(&mount_list);
file_to_vector(buffer, &mount_list);
// Find the cache block name if not found yet
if (strlen(cache_block) == 0) {
vec_for_each(&mount_list, line) {
if (strstr(line, " /cache ")) {
sscanf(line, "%256s", cache_block);
break;
}
}
}
// First unmount dummy skeletons, /sbin links, cache mounts, and mirrors
vec_for_each(&mount_list, line) {
if (strstr(line, "tmpfs /system") || strstr(line, "tmpfs /vendor") || strstr(line, "tmpfs /sbin")
|| (strstr(line, cache_block) && (strstr(line, " /system") || strstr(line, " /vendor")))
|| strstr(line, MIRRDIR)) {
sscanf(line, "%*s %512s", buffer);
lazy_unmount(buffer);
}
free(line);
}
vec_destroy(&mount_list);
// Re-read mount infos
snprintf(buffer, sizeof(buffer), "/proc/%d/mounts", pid);
vec_init(&mount_list);
file_to_vector(buffer, &mount_list);
// Unmount any loop mounts and dummy mounts
vec_for_each(&mount_list, line) {
if (strstr(line, "/dev/block/loop") || strstr(line, DUMMDIR)) {
sscanf(line, "%*s %512s", buffer);
lazy_unmount(buffer);
}
free(line);
}
vec_destroy(&mount_list);
// All done, send resume signal
kill(pid, SIGCONT);
// Tell main process all is well
pid = 0;
xwrite(sv[1], &pid, sizeof(pid));
}
// Should never go here
}

4
jni/magiskhide/hide_utils.c
View File

@ -44,7 +44,7 @@ void manage_selinux() {
}
void hide_sensitive_props() {
LOGI("hide_pre_proc: Hiding sensitive props\n");
LOGI("hide_utils: Hiding sensitive props\n");
// Hide all sensitive props
char *value;
@ -66,7 +66,7 @@ void relink_sbin() {
struct dirent *entry;
char from[PATH_MAX], to[PATH_MAX];
LOGI("hide_pre_proc: Re-linking /sbin\n");
LOGI("hide_utils: Re-linking /sbin\n");
xmount(NULL, "/", NULL, MS_REMOUNT, NULL);
xrename("/sbin", "/sbin_orig");

7
jni/magiskhide/magiskhide.h
View File

@ -6,13 +6,10 @@
// Kill process
void kill_proc(int pid);
// Hide daemon
int hide_daemon();
// Process monitor
void proc_monitor();
// Preprocess
// Utility functions
void manage_selinux();
void hide_sensitive_props();
void relink_sbin();
@ -23,7 +20,7 @@ int rm_list(char *proc);
int init_list();
int destroy_list();
extern int sv[2], hide_pid, hideEnabled;
extern int hideEnabled;
extern struct vector *hide_list;
extern pthread_mutex_t hide_lock, file_lock;

172
jni/magiskhide/proc_monitor.c
View File

@ -1,7 +1,8 @@
/* proc_monitor.c - Monitor am_proc_start events
/* proc_monitor.c - Monitor am_proc_start events and unmount
*
* We monitor the logcat am_proc_start events, pause it,
* and send the target PID to hide daemon ASAP
* We monitor the logcat am_proc_start events. When a target starts up,
* we pause it ASAP, and fork a new process to join its mount namespace
* and do all the unmounting/mocking
*/
#include <stdlib.h>
@ -12,18 +13,17 @@
#include <pthread.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/mount.h>
#include "magisk.h"
#include "utils.h"
#include "magiskhide.h"
static int zygote_num;
static char init_ns[32], zygote_ns[2][32];
static int log_pid, log_fd;
static char init_ns[32], zygote_ns[2][32], cache_block[256];
static int log_pid, log_fd, target_pid;
static char *buffer;
int sv[2], hide_pid = -1;
// Workaround for the lack of pthread_cancel
static void quit_pthread(int sig) {
err_handler = do_nothing;
@ -32,17 +32,14 @@ static void quit_pthread(int sig) {
free(buffer);
hideEnabled = 0;
// Kill the logging if needed
if (log_pid) {
if (log_pid > 0) {
kill(log_pid, SIGTERM);
waitpid(log_pid, NULL, 0);
close(log_fd);
log_fd = log_pid = 0;
}
int kill = -1;
// If process monitor dies, kill hide daemon too
write(sv[0], &kill, sizeof(kill));
close(sv[0]);
waitpid(hide_pid, NULL, 0);
// Resume process if possible
if (target_pid > 0)
kill(target_pid, SIGCONT);
pthread_mutex_destroy(&hide_lock);
pthread_mutex_destroy(&file_lock);
LOGD("proc_monitor: terminating...\n");
@ -54,15 +51,13 @@ static void proc_monitor_err() {
quit_pthread(SIGUSR1);
}
static void read_namespace(const int pid, char* target, const size_t size) {
static int read_namespace(const int pid, char* target, const size_t size) {
char path[32];
snprintf(path, sizeof(path), "/proc/%d/ns/mnt", pid);
if (access(path, R_OK) == -1) {
LOGE("proc_monitor: Your kernel doesn't support mount namespace :(\n");
proc_monitor_err();
return;
}
if (access(path, R_OK) == -1)
return 1;
xreadlink(path, target, size);
return 0;
}
static void store_zygote_ns(int pid) {
@ -74,6 +69,76 @@ static void store_zygote_ns(int pid) {
++zygote_num;
}
static void lazy_unmount(const char* mountpoint) {
if (umount2(mountpoint, MNT_DETACH) != -1)
LOGD("hide_daemon: Unmounted (%s)\n", mountpoint);
else
LOGD("hide_daemon: Unmount Failed (%s)\n", mountpoint);
}
static void hide_daemon_err() {
LOGD("hide_daemon: error occured, stopping magiskhide services\n");
_exit(-1);
}
static void hide_daemon(int pid) {
LOGD("hide_daemon: start unmount for pid=[%d]\n", pid);
// When an error occurs, report its failure to main process
err_handler = hide_daemon_err;
char *line;
struct vector mount_list;
manage_selinux();
relink_sbin();
if (switch_mnt_ns(pid))
return;
snprintf(buffer, PATH_MAX, "/proc/%d/mounts", pid);
vec_init(&mount_list);
file_to_vector(buffer, &mount_list);
// Find the cache block name if not found yet
if (cache_block[0] == '\0') {
vec_for_each(&mount_list, line) {
if (strstr(line, " /cache ")) {
sscanf(line, "%256s", cache_block);
break;
}
}
}
// First unmount dummy skeletons, /sbin links, cache mounts, and mirrors
vec_for_each(&mount_list, line) {
if (strstr(line, "tmpfs /system") || strstr(line, "tmpfs /vendor") || strstr(line, "tmpfs /sbin")
|| (strstr(line, cache_block) && (strstr(line, " /system") || strstr(line, " /vendor")))
|| strstr(line, MIRRDIR)) {
sscanf(line, "%*s %4096s", buffer);
lazy_unmount(buffer);
}
free(line);
}
vec_destroy(&mount_list);
// Re-read mount infos
snprintf(buffer, PATH_MAX, "/proc/%d/mounts", pid);
vec_init(&mount_list);
file_to_vector(buffer, &mount_list);
// Unmount any loop mounts and dummy mounts
vec_for_each(&mount_list, line) {
if (strstr(line, "/dev/block/loop") || strstr(line, DUMMDIR)) {
sscanf(line, "%*s %4096s", buffer);
lazy_unmount(buffer);
}
free(line);
}
// Free uo memory
vec_destroy(&mount_list);
}
void proc_monitor() {
// Register the cancel signal
struct sigaction act;
@ -83,12 +148,16 @@ void proc_monitor() {
// The error handler should stop magiskhide services
err_handler = proc_monitor_err;
log_pid = target_pid = -1;
int pid;
buffer = xmalloc(PATH_MAX);
cache_block[0] = '\0';
// Get the mount namespace of init
read_namespace(1, init_ns, 32);
if (read_namespace(1, init_ns, 32)) {
LOGE("proc_monitor: Your kernel doesn't support mount namespace :(\n");
proc_monitor_err();
}
LOGI("proc_monitor: init ns=%s\n", init_ns);
// Get the mount namespace of zygote
@ -109,20 +178,8 @@ void proc_monitor() {
break;
}
if (socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, sv) == -1)
quit_pthread(SIGUSR1);
/*
* The setns system call do not support multithread processes
* We have to fork a new process, and communicate with sockets
*/
if (hide_daemon())
quit_pthread(SIGUSR1);
close(sv[1]);
while (1) {
// Clear previous buffer
// Clear previous logcat buffer
system("logcat -b events -c");
// Monitor am_proc_start
@ -134,7 +191,7 @@ void proc_monitor() {
if (kill(log_pid, 0)) continue;
while(fdgets(buffer, PATH_MAX, log_fd)) {
int ret, comma = 0;
int pid, ret, comma = 0;
char *pos = buffer, *line, processName[256];
while(1) {
@ -159,10 +216,11 @@ void proc_monitor() {
pthread_mutex_lock(&hide_lock);
vec_for_each(hide_list, line) {
if (strcmp(processName, line) == 0) {
target_pid = pid;
while(1) {
ret = 1;
for (int i = 0; i < zygote_num; ++i) {
read_namespace(pid, buffer, 32);
read_namespace(target_pid, buffer, 32);
if (strcmp(buffer, zygote_ns[i]) == 0) {
usleep(50);
ret = 0;
@ -172,29 +230,39 @@ void proc_monitor() {
if (ret) break;
}
ret = 0;
// Send pause signal ASAP
if (kill(pid, SIGSTOP) == -1) continue;
if (kill(target_pid, SIGSTOP) == -1) continue;
LOGI("proc_monitor: %s (PID=%d ns=%s)\n", processName, pid, buffer);
LOGI("proc_monitor: %s (PID=%d ns=%s)\n", processName, target_pid, buffer);
// Unmount start
xwrite(sv[0], &pid, sizeof(pid));
/*
* The setns system call do not support multithread processes
* We have to fork a new process, setns, then do the unmounts
*/
int hide_pid = fork();
switch(hide_pid) {
case -1:
PLOGE("fork");
return;
case 0:
hide_daemon(target_pid);
_exit(0);
default:
break;
}
// Get the hide daemon return code
xxread(sv[0], &ret, sizeof(ret));
LOGD("proc_monitor: hide daemon response code: %d\n", ret);
// Wait till the unmount process is done
waitpid(hide_pid, &ret, 0);
if (WEXITSTATUS(ret))
quit_pthread(SIGUSR1);
// All done, send resume signal
kill(target_pid, SIGCONT);
target_pid = -1;
break;
}
}
pthread_mutex_unlock(&hide_lock);
if (ret) {
// Wait hide process to kill itself
waitpid(hide_pid, NULL, 0);
quit_pthread(SIGUSR1);
}
}
// For some reason it went here, restart logging