MarcoBuster/Magisk
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Magisk/native/jni/magiskboot/bootimg.cpp

458 lines
12 KiB
C++
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#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <libfdt.h>
#include <sys/mman.h>
#include <mincrypt/sha.h>
#include <mincrypt/sha256.h>
#include "bootimg.h"
#include "magiskboot.h"
#include "utils.h"
#include "logging.h"
static void dump(void *buf, size_t size, const char *filename) {
if (size == 0)
return;
int fd = creat(filename, 0644);
xwrite(fd, buf, size);
close(fd);
}
static size_t restore(const char *filename, int fd) {
int ifd = xopen(filename, O_RDONLY);
size_t size = lseek(ifd, 0, SEEK_END);
lseek(ifd, 0, SEEK_SET);
xsendfile(fd, ifd, NULL, size);
close(ifd);
return size;
}
static void restore_buf(int fd, const void *buf, size_t size) {
xwrite(fd, buf, size);
}
boot_img::~boot_img() {
munmap(map_addr, map_size);
delete hdr;
delete k_hdr;
delete r_hdr;
delete b_hdr;
}
#define CHROMEOS_RET 2
#define ELF32_RET 3
#define ELF64_RET 4
#define pos_align() pos = align(pos, page_size())
int boot_img::parse_image(const char * image) {
mmap_ro(image, (void **) &map_addr, &map_size);
// Parse image
fprintf(stderr, "Parsing boot image: [%s]\n", image);
for (uint8_t *head = map_addr; head < map_addr + map_size; ++head) {
size_t pos = 0;
switch (check_fmt(head, map_size)) {
case CHROMEOS:
// The caller should know it's chromeos, as it needs additional signing
flags |= CHROMEOS_FLAG;
break;
case DHTB:
flags |= DHTB_FLAG;
flags |= SEANDROID_FLAG;
fprintf(stderr, "DHTB_HDR\n");
break;
case ELF32:
exit(ELF32_RET);
case ELF64:
exit(ELF64_RET);
case BLOB:
flags |= BLOB_FLAG;
fprintf(stderr, "TEGRA_BLOB\n");
b_hdr = new blob_hdr();
memcpy(b_hdr, head, sizeof(blob_hdr));
break;
case AOSP:
// Read the header
if (((boot_img_hdr*) head)->page_size >= 0x02000000) {
flags |= PXA_FLAG;
fprintf(stderr, "PXA_BOOT_HDR\n");
hdr = new boot_img_hdr_pxa();
memcpy(hdr, head, sizeof(boot_img_hdr_pxa));
} else if (memcmp(((boot_img_hdr*) head)->cmdline, NOOKHD_MAGIC, 12) == 0
|| memcmp(((boot_img_hdr*) head)->cmdline, NOOKHD_NEW_MAGIC, 26) == 0) {
flags |= NOOKHD_FLAG;
fprintf(stderr, "NOOKHD_GREEN_LOADER\n");
head += NOOKHD_PRE_HEADER_SZ - 1;
continue;
} else if (memcmp(((boot_img_hdr*) head)->name, ACCLAIM_MAGIC, 10) == 0) {
flags |= ACCLAIM_FLAG;
fprintf(stderr, "ACCLAIM_BAUWKSBOOT\n");
head += ACCLAIM_PRE_HEADER_SZ - 1;
continue;
} else {
hdr = new boot_img_hdr();
memcpy(hdr, head, sizeof(boot_img_hdr));
}
pos += page_size();
flags |= id()[SHA_DIGEST_SIZE] ? SHA256_FLAG : 0;
print_hdr();
kernel = head + pos;
pos += hdr->kernel_size;
pos_align();
ramdisk = head + pos;
pos += hdr->ramdisk_size;
pos_align();
second = head + pos;
pos += hdr->second_size;
pos_align();
extra = head + pos;
pos += extra_size();
pos_align();
recov_dtbo = head + pos;
pos += recovery_dtbo_size();
pos_align();
if (pos < map_size) {
tail = head + pos;
tail_size = map_size - (tail - map_addr);
}
// Check tail info, currently only for LG Bump and Samsung SEANDROIDENFORCE
if (tail_size >= 16 && memcmp(tail, SEANDROID_MAGIC, 16) == 0) {
flags |= SEANDROID_FLAG;
} else if (tail_size >= 16 && memcmp(tail, LG_BUMP_MAGIC, 16) == 0) {
flags |= LG_BUMP_FLAG;
}
find_dtb();
k_fmt = check_fmt(kernel, hdr->kernel_size);
r_fmt = check_fmt(ramdisk, hdr->ramdisk_size);
// Check MTK
if (k_fmt == MTK) {
fprintf(stderr, "MTK_KERNEL_HDR\n");
flags |= MTK_KERNEL;
k_hdr = new mtk_hdr();
memcpy(k_hdr, kernel, sizeof(mtk_hdr));
fprintf(stderr, "KERNEL [%u]\n", k_hdr->size);
fprintf(stderr, "NAME [%s]\n", k_hdr->name);
kernel += 512;
hdr->kernel_size -= 512;
k_fmt = check_fmt(kernel, hdr->kernel_size);
}
if (r_fmt == MTK) {
fprintf(stderr, "MTK_RAMDISK_HDR\n");
flags |= MTK_RAMDISK;
r_hdr = new mtk_hdr();
memcpy(r_hdr, ramdisk, sizeof(mtk_hdr));
fprintf(stderr, "RAMDISK [%u]\n", r_hdr->size);
fprintf(stderr, "NAME [%s]\n", r_hdr->name);
ramdisk += 512;
hdr->ramdisk_size -= 512;
r_fmt = check_fmt(ramdisk, hdr->ramdisk_size);
}
char fmt[16];
get_fmt_name(k_fmt, fmt);
fprintf(stderr, "KERNEL_FMT [%s]\n", fmt);
get_fmt_name(r_fmt, fmt);
fprintf(stderr, "RAMDISK_FMT [%s]\n", fmt);
return flags & CHROMEOS_FLAG ? CHROMEOS_RET : 0;
default:
break;
}
}
LOGE("No boot image magic found!\n");
exit(1);
}
void boot_img::find_dtb() {
for (uint32_t i = 0; i < hdr->kernel_size; ++i) {
if (memcmp(kernel + i, DTB_MAGIC, 4))
continue;
// Check that fdt_header.totalsize does not overflow kernel image size
uint32_t dt_sz = fdt32_to_cpu(*(uint32_t *)(kernel + i + 4));
if (dt_sz > hdr->kernel_size - i) {
fprintf(stderr, "Invalid DTB detection at 0x%x: size (%u) > remaining (%u)\n",
i, dt_sz, hdr->kernel_size - i);
continue;
}
// Check that fdt_header.off_dt_struct does not overflow kernel image size
uint32_t dt_struct_offset = fdt32_to_cpu(*(uint32_t *)(kernel + i + 8));
if (dt_struct_offset > hdr->kernel_size - i) {
fprintf(stderr, "Invalid DTB detection at 0x%x: "
"struct offset (%u) > remaining (%u)\n",
i, dt_struct_offset, hdr->kernel_size - i);
continue;
}
// Check that fdt_node_header.tag of first node is FDT_BEGIN_NODE
uint32_t dt_begin_node = fdt32_to_cpu(*(uint32_t *)(kernel + i + dt_struct_offset));
if (dt_begin_node != FDT_BEGIN_NODE) {
fprintf(stderr, "Invalid DTB detection at 0x%x: "
"header tag of first node != FDT_BEGIN_NODE\n", i);
continue;
}
dtb = kernel + i;
dt_size = hdr->kernel_size - i;
hdr->kernel_size = i;
fprintf(stderr, "DTB [%u]\n", dt_size);
break;
}
}
void boot_img::print_hdr() {
fprintf(stderr, "HEADER_VER [%u]\n", header_version());
fprintf(stderr, "KERNEL_SZ [%u]\n", hdr->kernel_size);
fprintf(stderr, "RAMDISK_SZ [%u]\n", hdr->ramdisk_size);
fprintf(stderr, "SECOND_SZ [%u]\n", hdr->second_size);
fprintf(stderr, "EXTRA_SZ [%u]\n", extra_size());
fprintf(stderr, "RECOV_DTBO_SZ [%u]\n", recovery_dtbo_size());
uint32_t ver = os_version();
if (ver) {
int a,b,c,y,m = 0;
int version, patch_level;
version = ver >> 11;
patch_level = ver & 0x7ff;
a = (version >> 14) & 0x7f;
b = (version >> 7) & 0x7f;
c = version & 0x7f;
fprintf(stderr, "OS_VERSION [%d.%d.%d]\n", a, b, c);
y = (patch_level >> 4) + 2000;
m = patch_level & 0xf;
fprintf(stderr, "PATCH_LEVEL [%d-%02d]\n", y, m);
}
fprintf(stderr, "PAGESIZE [%u]\n", page_size());
fprintf(stderr, "NAME [%s]\n", name());
fprintf(stderr, "CMDLINE [%.512s%.1024s]\n", cmdline(), extra_cmdline());
fprintf(stderr, "CHECKSUM [");
for (int i = 0; id()[i]; ++i)
fprintf(stderr, "%02x", id()[i]);
fprintf(stderr, "]\n");
}
int unpack(const char *image) {
boot_img boot {};
int ret = boot.parse_image(image);
int fd;
// Dump kernel
if (COMPRESSED(boot.k_fmt)) {
fd = creat(KERNEL_FILE, 0644);
decompress(boot.k_fmt, fd, boot.kernel, boot.hdr->kernel_size);
close(fd);
} else {
dump(boot.kernel, boot.hdr->kernel_size, KERNEL_FILE);
}
// Dump dtb
dump(boot.dtb, boot.dt_size, DTB_FILE);
// Dump ramdisk
if (COMPRESSED(boot.r_fmt)) {
fd = creat(RAMDISK_FILE, 0644);
decompress(boot.r_fmt, fd, boot.ramdisk, boot.hdr->ramdisk_size);
close(fd);
} else {
dump(boot.ramdisk, boot.hdr->ramdisk_size, RAMDISK_FILE);
}
// Dump second
dump(boot.second, boot.hdr->second_size, SECOND_FILE);
// Dump extra
dump(boot.extra, boot.extra_size(), EXTRA_FILE);
// Dump recovery_dtbo
dump(boot.recov_dtbo, boot.recovery_dtbo_size(), RECV_DTBO_FILE);
return ret;
}
#define file_align() write_zero(fd, align_off(lseek(fd, 0, SEEK_CUR) - header_off, boot.page_size()))
void repack(const char* orig_image, const char* out_image) {
boot_img boot {};
off_t header_off, kernel_off, ramdisk_off, second_off, extra_off;
// Parse original image
boot.parse_image(orig_image);
// Reset sizes
boot.hdr->kernel_size = 0;
boot.hdr->ramdisk_size = 0;
boot.hdr->second_size = 0;
boot.dt_size = 0;
fprintf(stderr, "Repack to boot image: [%s]\n", out_image);
// Create new image
int fd = creat(out_image, 0644);
if (boot.flags & DHTB_FLAG) {
// Skip DHTB header
write_zero(fd, 512);
} else if (boot.flags & BLOB_FLAG) {
// Skip blob header
write_zero(fd, sizeof(blob_hdr));
} else if (boot.flags & NOOKHD_FLAG) {
restore_buf(fd, boot.map_addr, NOOKHD_PRE_HEADER_SZ);
} else if (boot.flags & ACCLAIM_FLAG) {
restore_buf(fd, boot.map_addr, ACCLAIM_PRE_HEADER_SZ);
}
// Skip a page for header
header_off = lseek(fd, 0, SEEK_CUR);
write_zero(fd, boot.page_size());
// kernel
kernel_off = lseek(fd, 0, SEEK_CUR);
if (boot.flags & MTK_KERNEL) {
// Skip MTK header
write_zero(fd, 512);
}
if (access(KERNEL_FILE, R_OK) == 0) {
if (COMPRESSED(boot.k_fmt)) {
size_t raw_size;
void *kernel_raw;
mmap_ro(KERNEL_FILE, &kernel_raw, &raw_size);
boot.hdr->kernel_size = compress(boot.k_fmt, fd, kernel_raw, raw_size);
munmap(kernel_raw, raw_size);
} else {
boot.hdr->kernel_size = restore(KERNEL_FILE, fd);
}
}
// dtb
if (access(DTB_FILE, R_OK) == 0)
boot.hdr->kernel_size += restore(DTB_FILE, fd);
file_align();
// ramdisk
ramdisk_off = lseek(fd, 0, SEEK_CUR);
if (boot.flags & MTK_RAMDISK) {
// Skip MTK header
write_zero(fd, 512);
}
if (access(RAMDISK_FILE, R_OK) == 0) {
if (COMPRESSED(boot.r_fmt)) {
size_t cpio_size;
void *cpio;
mmap_ro(RAMDISK_FILE, &cpio, &cpio_size);
boot.hdr->ramdisk_size = compress(boot.r_fmt, fd, cpio, cpio_size);
munmap(cpio, cpio_size);
} else {
boot.hdr->ramdisk_size = restore(RAMDISK_FILE, fd);
}
file_align();
}
// second
second_off = lseek(fd, 0, SEEK_CUR);
if (access(SECOND_FILE, R_OK) == 0) {
boot.hdr->second_size = restore(SECOND_FILE, fd);
file_align();
}
// extra
extra_off = lseek(fd, 0, SEEK_CUR);
if (access(EXTRA_FILE, R_OK) == 0) {
boot.extra_size(restore(EXTRA_FILE, fd));
file_align();
}
// recovery_dtbo
if (access(RECV_DTBO_FILE, R_OK) == 0) {
boot.recovery_dtbo_offset(lseek(fd, 0, SEEK_CUR));
boot.recovery_dtbo_size(restore(RECV_DTBO_FILE, fd));
file_align();
}
// Append tail info
if (boot.flags & SEANDROID_FLAG) {
restore_buf(fd, SEANDROID_MAGIC "\xFF\xFF\xFF\xFF", 20);
}
if (boot.flags & LG_BUMP_FLAG) {
restore_buf(fd, LG_BUMP_MAGIC, 16);
}
close(fd);
// Map output image as rw
munmap(boot.map_addr, boot.map_size);
mmap_rw(out_image, (void **) &boot.map_addr, &boot.map_size);
// MTK headers
if (boot.flags & MTK_KERNEL) {
boot.k_hdr->size = boot.hdr->kernel_size;
boot.hdr->kernel_size += 512;
memcpy(boot.map_addr + kernel_off, boot.k_hdr, sizeof(mtk_hdr));
}
if (boot.flags & MTK_RAMDISK) {
boot.r_hdr->size = boot.hdr->ramdisk_size;
boot.hdr->ramdisk_size += 512;
memcpy(boot.map_addr + ramdisk_off, boot.r_hdr, sizeof(mtk_hdr));
}
// Update checksum
HASH_CTX ctx;
(boot.flags & SHA256_FLAG) ? SHA256_init(&ctx) : SHA_init(&ctx);
uint32_t size = boot.hdr->kernel_size;
HASH_update(&ctx, boot.map_addr + kernel_off, size);
HASH_update(&ctx, &size, sizeof(size));
size = boot.hdr->ramdisk_size;
HASH_update(&ctx, boot.map_addr + ramdisk_off, size);
HASH_update(&ctx, &size, sizeof(size));
size = boot.hdr->second_size;
HASH_update(&ctx, boot.map_addr + second_off, size);
HASH_update(&ctx, &size, sizeof(size));
size = boot.extra_size();
if (size) {
HASH_update(&ctx, boot.map_addr + extra_off, size);
HASH_update(&ctx, &size, sizeof(size));
}
if (boot.header_version()) {
size = boot.recovery_dtbo_size();
HASH_update(&ctx, boot.map_addr + boot.recovery_dtbo_offset(), size);
HASH_update(&ctx, &size, sizeof(size));
}
memset(boot.id(), 0, 32);
memcpy(boot.id(), HASH_final(&ctx),
(boot.flags & SHA256_FLAG) ? SHA256_DIGEST_SIZE : SHA_DIGEST_SIZE);
// Print new image info
boot.print_hdr();
// Main header
memcpy(boot.map_addr + header_off, boot.hdr, boot.hdr_size());
if (boot.flags & DHTB_FLAG) {
// DHTB header
dhtb_hdr *hdr = reinterpret_cast<dhtb_hdr *>(boot.map_addr);
memcpy(hdr, DHTB_MAGIC, 8);
hdr->size = boot.map_size - 512;
SHA256_hash(boot.map_addr + 512, hdr->size, hdr->checksum);
} else if (boot.flags & BLOB_FLAG) {
// Blob headers
boot.b_hdr->size = boot.map_size - sizeof(blob_hdr);
memcpy(boot.map_addr, boot.b_hdr, sizeof(blob_hdr));
}
}
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