mirror of
https://github.com/topjohnwu/Magisk.git
synced 2025-06-13 13:47:44 +02:00
Source reorganization
This commit is contained in:
topjohnwu
475
native/jni/misc/init.c
Normal file
475
native/jni/misc/init.c
Normal file
@ -0,0 +1,475 @@
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/* init.c - Pre-init Magisk support
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*
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* This code has to be compiled statically to work properly.
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*
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* To unify Magisk support for both legacy "normal" devices and new skip_initramfs devices,
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* magisk binary compilation is split into two parts - first part only compiles "magisk".
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* The python build script will load the magisk main binary and compress with lzma2, dumping
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* the results into "dump.h". The "magisk" binary is embedded into this binary, and will
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* get extracted to the overlay folder along with init.magisk.rc.
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*
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* This tool does all pre-init operations to setup a Magisk environment, which pathces rootfs
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* on the fly, providing fundamental support such as init, init.rc, and sepolicy patching.
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*
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* Magiskinit is also responsible for constructing a proper rootfs on skip_initramfs devices.
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* On skip_initramfs devices, it will parse kernel cmdline, mount sysfs, parse through
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* uevent files to make the system (or vendor if available) block device node, then copy
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* rootfs files from system.
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*
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* This tool will be replaced with the real init to continue the boot process, but hardlinks are
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* preserved as it also provides CLI for sepolicy patching (magiskpolicy)
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <dirent.h>
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#include <fcntl.h>
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#include <libgen.h>
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#include <sys/stat.h>
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#include <sys/types.h>
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#include <sys/mount.h>
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#include <sys/mman.h>
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#include <sys/sendfile.h>
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#include <sys/sysmacros.h>
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#include <xz.h>
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#include "binaries.h"
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#include "binaries_arch.h"
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#include "magiskrc.h"
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#include "utils.h"
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#include "daemon.h"
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#include "magisk.h"
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#include "flags.h"
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#define DEFAULT_DT_DIR "/proc/device-tree/firmware/android"
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int (*init_applet_main[]) (int, char *[]) = { magiskpolicy_main, magiskpolicy_main, NULL };
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struct cmdline {
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char skip_initramfs;
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char slot[3];
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char dt_dir[128];
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};
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struct device {
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dev_t major;
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dev_t minor;
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char devname[32];
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char partname[32];
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char path[64];
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};
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static void parse_cmdline(struct cmdline *cmd) {
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// cleanup
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memset(cmd, 0, sizeof(*cmd));
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char cmdline[4096];
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int fd = open("/proc/cmdline", O_RDONLY | O_CLOEXEC);
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cmdline[read(fd, cmdline, sizeof(cmdline))] = '\0';
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close(fd);
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for (char *tok = strtok(cmdline, " "); tok; tok = strtok(NULL, " ")) {
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if (strncmp(tok, "androidboot.slot_suffix", 23) == 0) {
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sscanf(tok, "androidboot.slot_suffix=%s", cmd->slot);
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} else if (strncmp(tok, "androidboot.slot", 16) == 0) {
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cmd->slot[0] = '_';
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sscanf(tok, "androidboot.slot=%c", cmd->slot + 1);
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} else if (strcmp(tok, "skip_initramfs") == 0) {
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cmd->skip_initramfs = 1;
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} else if (strncmp(tok, "androidboot.android_dt_dir", 26) == 0) {
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sscanf(tok, "androidboot.android_dt_dir=%s", cmd->dt_dir);
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}
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}
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if (cmd->dt_dir[0] == '\0')
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strcpy(cmd->dt_dir, DEFAULT_DT_DIR);
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LOGD("cmdline: skip_initramfs[%d] slot[%s] dt_dir[%s]\n", cmd->skip_initramfs, cmd->slot, cmd->dt_dir);
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}
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static void parse_device(struct device *dev, const char *uevent) {
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dev->partname[0] = '\0';
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FILE *fp = xfopen(uevent, "r");
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char buf[64];
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while (fgets(buf, sizeof(buf), fp)) {
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if (strncmp(buf, "MAJOR", 5) == 0) {
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sscanf(buf, "MAJOR=%ld", (long*) &dev->major);
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} else if (strncmp(buf, "MINOR", 5) == 0) {
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sscanf(buf, "MINOR=%ld", (long*) &dev->minor);
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} else if (strncmp(buf, "DEVNAME", 7) == 0) {
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sscanf(buf, "DEVNAME=%s", dev->devname);
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} else if (strncmp(buf, "PARTNAME", 8) == 0) {
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sscanf(buf, "PARTNAME=%s", dev->partname);
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}
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}
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fclose(fp);
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LOGD("%s [%s] (%u, %u)\n", dev->devname, dev->partname, (unsigned) dev->major, (unsigned) dev->minor);
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}
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static int setup_block(struct device *dev, const char *partname) {
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char path[128];
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struct dirent *entry;
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DIR *dir = opendir("/sys/dev/block");
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if (dir == NULL)
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return 1;
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int found = 0;
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while ((entry = readdir(dir))) {
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if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
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continue;
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sprintf(path, "/sys/dev/block/%s/uevent", entry->d_name);
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parse_device(dev, path);
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if (strcasecmp(dev->partname, partname) == 0) {
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sprintf(dev->path, "/dev/block/%s", dev->devname);
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found = 1;
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break;
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}
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}
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closedir(dir);
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if (!found)
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return 1;
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mkdir("/dev", 0755);
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mkdir("/dev/block", 0755);
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mknod(dev->path, S_IFBLK | 0600, makedev(dev->major, dev->minor));
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return 0;
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}
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static int read_fstab_dt(const struct cmdline *cmd, const char *mnt_point, char *partname) {
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char buf[128];
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struct stat st;
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sprintf(buf, "/%s", mnt_point);
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lstat(buf, &st);
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// Don't early mount if the mount point is symlink
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if (S_ISLNK(st.st_mode))
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return 1;
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sprintf(buf, "%s/fstab/%s/dev", cmd->dt_dir, mnt_point);
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if (access(buf, F_OK) == 0) {
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int fd = open(buf, O_RDONLY | O_CLOEXEC);
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read(fd, buf, sizeof(buf));
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close(fd);
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char *name = strrchr(buf, '/') + 1;
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sprintf(partname, "%s%s", name, strend(name, cmd->slot) ? cmd->slot : "");
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return 0;
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}
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return 1;
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}
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static int verify_precompiled() {
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DIR *dir;
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struct dirent *entry;
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int fd;
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char sys_sha[64], ven_sha[64];
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// init the strings with different value
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sys_sha[0] = 0;
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ven_sha[0] = 1;
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dir = opendir(NONPLAT_POLICY_DIR);
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while ((entry = readdir(dir))) {
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if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
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continue;
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if (strend(entry->d_name, ".sha256") == 0) {
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fd = openat(dirfd(dir), entry->d_name, O_RDONLY | O_CLOEXEC);
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read(fd, ven_sha, sizeof(ven_sha));
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close(fd);
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break;
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}
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}
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closedir(dir);
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dir = opendir(PLAT_POLICY_DIR);
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while ((entry = readdir(dir))) {
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if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
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continue;
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if (strend(entry->d_name, ".sha256") == 0) {
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fd = openat(dirfd(dir), entry->d_name, O_RDONLY | O_CLOEXEC);
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read(fd, sys_sha, sizeof(sys_sha));
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close(fd);
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break;
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}
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}
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closedir(dir);
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LOGD("sys_sha[%.*s]\nven_sha[%.*s]\n", sizeof(sys_sha), sys_sha, sizeof(ven_sha), ven_sha);
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return memcmp(sys_sha, ven_sha, sizeof(sys_sha)) == 0;
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}
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static int patch_sepolicy() {
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int init_patch = 0;
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if (access(SPLIT_PRECOMPILE, R_OK) == 0 && verify_precompiled()) {
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init_patch = 1;
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load_policydb(SPLIT_PRECOMPILE);
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} else if (access(SPLIT_PLAT_CIL, R_OK) == 0) {
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init_patch = 1;
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compile_split_cil();
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} else if (access("/sepolicy", R_OK) == 0) {
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load_policydb("/sepolicy");
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} else {
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return 1;
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}
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sepol_magisk_rules();
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sepol_allow(SEPOL_PROC_DOMAIN, ALL, ALL, ALL);
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dump_policydb("/sepolicy");
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// Remove the stupid debug sepolicy and use our own
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if (access("/sepolicy_debug", F_OK) == 0) {
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unlink("/sepolicy_debug");
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link("/sepolicy", "/sepolicy_debug");
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}
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if (init_patch) {
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// Force init to load /sepolicy
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void *addr;
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size_t size;
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mmap_rw("/init", &addr, &size);
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for (int i = 0; i < size; ++i) {
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if (memcmp(addr + i, SPLIT_PLAT_CIL, sizeof(SPLIT_PLAT_CIL) - 1) == 0) {
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memcpy(addr + i + sizeof(SPLIT_PLAT_CIL) - 4, "xxx", 3);
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break;
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||||
}
|
||||
}
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||||
munmap(addr, size);
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||||
}
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||||
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return 0;
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||||
}
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||||
|
||||
static int unxz(int fd, const void *buf, size_t size) {
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uint8_t out[8192];
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||||
xz_crc32_init();
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struct xz_dec *dec = xz_dec_init(XZ_DYNALLOC, 1 << 26);
|
||||
struct xz_buf b = {
|
||||
.in = buf,
|
||||
.in_pos = 0,
|
||||
.in_size = size,
|
||||
.out = out,
|
||||
.out_pos = 0,
|
||||
.out_size = sizeof(out)
|
||||
};
|
||||
enum xz_ret ret;
|
||||
do {
|
||||
ret = xz_dec_run(dec, &b);
|
||||
if (ret != XZ_OK && ret != XZ_STREAM_END)
|
||||
return 1;
|
||||
write(fd, out, b.out_pos);
|
||||
b.out_pos = 0;
|
||||
} while (b.in_pos != size);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int dump_magisk(const char *path, mode_t mode) {
|
||||
int fd = creat(path, mode);
|
||||
if (fd < 0)
|
||||
return 1;
|
||||
if (unxz(fd, magisk_xz, sizeof(magisk_xz)))
|
||||
return 1;
|
||||
close(fd);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int dump_manager(const char *path, mode_t mode) {
|
||||
int fd = creat(path, mode);
|
||||
if (fd < 0)
|
||||
return 1;
|
||||
if (unxz(fd, manager_xz, sizeof(manager_xz)))
|
||||
return 1;
|
||||
close(fd);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static int dump_magiskrc(const char *path, mode_t mode) {
|
||||
int fd = creat(path, mode);
|
||||
if (fd < 0)
|
||||
return 1;
|
||||
char startup_svc[8], late_start_svc[8], rc[sizeof(magiskrc) + 100];
|
||||
gen_rand_str(startup_svc, sizeof(startup_svc));
|
||||
do {
|
||||
gen_rand_str(late_start_svc, sizeof(late_start_svc));
|
||||
} while (strcmp(startup_svc, late_start_svc) == 0);
|
||||
int size = sprintf(rc, magiskrc, startup_svc, startup_svc, late_start_svc);
|
||||
xwrite(fd, rc, size);
|
||||
close(fd);
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void patch_socket_name(const char *path) {
|
||||
void *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);
|
||||
}
|
||||
|
||||
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);
|
||||
else if (strcmp(argv[2], "magiskrc") == 0)
|
||||
return dump_magiskrc(argv[3], 0755);
|
||||
}
|
||||
|
||||
#ifdef MAGISK_DEBUG
|
||||
log_cb.d = vprintf;
|
||||
#endif
|
||||
|
||||
// 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);
|
||||
|
||||
// Backup self
|
||||
rename("/init", "/init.bak");
|
||||
|
||||
// Communicate with kernel using procfs and sysfs
|
||||
mkdir("/proc", 0755);
|
||||
xmount("proc", "/proc", "proc", 0, NULL);
|
||||
mkdir("/sys", 0755);
|
||||
xmount("sysfs", "/sys", "sysfs", 0, NULL);
|
||||
|
||||
struct cmdline cmd;
|
||||
parse_cmdline(&cmd);
|
||||
|
||||
/* ***********
|
||||
* Initialize
|
||||
* ***********/
|
||||
|
||||
int root = open("/", O_RDONLY | O_CLOEXEC);
|
||||
int mnt_system = 0;
|
||||
int mnt_vendor = 0;
|
||||
|
||||
if (cmd.skip_initramfs) {
|
||||
// Clear rootfs
|
||||
excl_list = (const char *[]) { "overlay", ".backup", "proc", "sys", "init.bak", NULL };
|
||||
frm_rf(root);
|
||||
} else {
|
||||
// Revert original init binary
|
||||
link("/.backup/init", "/init");
|
||||
}
|
||||
|
||||
// Do not go further if system_root device is booting as recovery
|
||||
if (!cmd.skip_initramfs && access("/sbin/recovery", F_OK) == 0) {
|
||||
// Remove Magisk traces
|
||||
rm_rf("/.backup");
|
||||
goto exec_init;
|
||||
}
|
||||
|
||||
/* ************
|
||||
* Early Mount
|
||||
* ************/
|
||||
|
||||
struct device dev;
|
||||
char partname[32];
|
||||
|
||||
if (cmd.skip_initramfs) {
|
||||
sprintf(partname, "system%s", cmd.slot);
|
||||
setup_block(&dev, partname);
|
||||
xmkdir("/system_root", 0755);
|
||||
xmount(dev.path, "/system_root", "ext4", MS_RDONLY, NULL);
|
||||
int system_root = open("/system_root", O_RDONLY | O_CLOEXEC);
|
||||
|
||||
// Clone rootfs except /system
|
||||
excl_list = (const char *[]) { "system", NULL };
|
||||
clone_dir(system_root, root);
|
||||
close(system_root);
|
||||
|
||||
xmkdir("/system", 0755);
|
||||
xmount("/system_root/system", "/system", NULL, MS_BIND, NULL);
|
||||
} else if (read_fstab_dt(&cmd, "system", partname) == 0) {
|
||||
setup_block(&dev, partname);
|
||||
xmount(dev.path, "/system", "ext4", MS_RDONLY, NULL);
|
||||
mnt_system = 1;
|
||||
}
|
||||
|
||||
if (read_fstab_dt(&cmd, "vendor", partname) == 0) {
|
||||
setup_block(&dev, partname);
|
||||
xmount(dev.path, "/vendor", "ext4", MS_RDONLY, NULL);
|
||||
mnt_vendor = 1;
|
||||
}
|
||||
|
||||
/* ****************
|
||||
* Ramdisk Patches
|
||||
* ****************/
|
||||
|
||||
// Handle ramdisk overlays
|
||||
int fd = open("/overlay", O_RDONLY | O_CLOEXEC);
|
||||
if (fd >= 0) {
|
||||
mv_dir(fd, root);
|
||||
close(fd);
|
||||
rmdir("/overlay");
|
||||
}
|
||||
|
||||
// Patch init.rc to load magisk scripts
|
||||
int injected = 0;
|
||||
char tok[4096];
|
||||
FILE *fp = xfopen("/init.rc", "r");
|
||||
fd = creat("/init.rc.new", 0750);
|
||||
while(fgets(tok, sizeof(tok), fp)) {
|
||||
if (!injected && strncmp(tok, "import", 6) == 0) {
|
||||
if (strstr(tok, "init.magisk.rc")) {
|
||||
injected = 1;
|
||||
} else {
|
||||
xwrite(fd, "import /init.magisk.rc\n", 23);
|
||||
injected = 1;
|
||||
}
|
||||
} else if (strstr(tok, "selinux.reload_policy")) {
|
||||
// Do not allow sepolicy patch
|
||||
continue;
|
||||
}
|
||||
xwrite(fd, tok, strlen(tok));
|
||||
}
|
||||
fclose(fp);
|
||||
close(fd);
|
||||
rename("/init.rc.new", "/init.rc");
|
||||
|
||||
// Patch sepolicy
|
||||
patch_sepolicy();
|
||||
|
||||
// Dump binaries
|
||||
dump_magiskrc(MAGISKRC, 0750);
|
||||
dump_magisk("/sbin/magisk", 0755);
|
||||
patch_socket_name("/sbin/magisk");
|
||||
rename("/init.bak", "/sbin/magiskinit");
|
||||
|
||||
exec_init:
|
||||
// Clean up
|
||||
close(root);
|
||||
umount("/proc");
|
||||
umount("/sys");
|
||||
if (mnt_system)
|
||||
umount("/system");
|
||||
if (mnt_vendor)
|
||||
umount("/vendor");
|
||||
|
||||
execv("/init", argv);
|
||||
}
|
||||
Reference in New Issue
Block a user