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Magisk/native/jni/magiskboot/bootimg.c
Shaka Huang 0b3192c4d5 Check dtb even if kernel is not available 
By the flow of unpacking boot image of Chrome OS there will be no kernel file but an dtb image. In that case the dtb image won’t be added when repacking boot image.

Signed-off-by: Shaka Huang <shakalaca@gmail.com>
2018-03-03 20:57:55 +08:00

432 lines
12 KiB
C
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#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/mman.h>
#include "bootimg.h"
#include "magiskboot.h"
#include "utils.h"
#include "logging.h"
#include "mincrypt/sha.h"
#include "mincrypt/sha256.h"
#define INSUF_BLOCK_RET 2
#define CHROMEOS_RET 3
#define ELF32_RET 4
#define ELF64_RET 5
// Macros to determine header on-the-go
#define lheader(b, e, o) \
((b)->flags & PXA_FLAG) ? \
(((struct pxa_boot_img_hdr*) (b)->hdr)->e o) : \
(((struct boot_img_hdr*) (b)->hdr)->e o)
#define header(b, e) (lheader(b, e,))
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);
}
static void print_hdr(const boot_img *boot) {
fprintf(stderr, "KERNEL [%u]\n", header(boot, kernel_size));
fprintf(stderr, "RAMDISK [%u]\n", header(boot, ramdisk_size));
fprintf(stderr, "SECOND [%u]\n", header(boot, second_size));
fprintf(stderr, "EXTRA [%u]\n", header(boot, extra_size));
fprintf(stderr, "PAGESIZE [%u]\n", header(boot, page_size));
if (!(boot->flags & PXA_FLAG)) {
uint32_t os_version = ((boot_img_hdr*) boot->hdr)->os_version;
if (os_version) {
int a,b,c,y,m = 0;
int version, patch_level;
version = os_version >> 11;
patch_level = os_version & 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, "NAME [%s]\n", header(boot, name));
fprintf(stderr, "CMDLINE [%s]\n", header(boot, cmdline));
fprintf(stderr, "CHECKSUM [");
for (int i = 0; i < ((boot->flags & SHA256_FLAG) ? SHA256_DIGEST_SIZE : SHA_DIGEST_SIZE); ++i)
fprintf(stderr, "%02x", header(boot, id)[i]);
fprintf(stderr, "]\n");
}
static void clean_boot(boot_img *boot) {
munmap(boot->map_addr, boot->map_size);
free(boot->hdr);
free(boot->k_hdr);
free(boot->r_hdr);
free(boot->b_hdr);
memset(boot, 0, sizeof(*boot));
}
#define pos_align() pos = align(pos, header(boot, page_size))
int parse_img(const char *image, boot_img *boot) {
memset(boot, 0, sizeof(*boot));
int is_blk = mmap_ro(image, &boot->map_addr, &boot->map_size);
// Parse image
fprintf(stderr, "Parsing boot image: [%s]\n", image);
for (void *head = boot->map_addr; head < boot->map_addr + boot->map_size; ++head) {
size_t pos = 0;
switch (check_fmt(head, boot->map_size)) {
case CHROMEOS:
// The caller should know it's chromeos, as it needs additional signing
boot->flags |= CHROMEOS_FLAG;
continue;
case DHTB:
boot->flags |= DHTB_FLAG;
boot->flags |= SEANDROID_FLAG;
fprintf(stderr, "DHTB_HDR\n");
continue;
case ELF32:
exit(ELF32_RET);
case ELF64:
exit(ELF64_RET);
case BLOB:
boot->flags |= BLOB_FLAG;
fprintf(stderr, "TEGRA_BLOB\n");
boot->b_hdr = malloc(sizeof(blob_hdr));
memcpy(boot->b_hdr, head, sizeof(blob_hdr));
continue;
case AOSP:
// Read the header
if (((boot_img_hdr*) head)->page_size >= 0x02000000) {
boot->flags |= PXA_FLAG;
fprintf(stderr, "PXA_BOOT_HDR\n");
boot->hdr = malloc(sizeof(pxa_boot_img_hdr));
memcpy(boot->hdr, head, sizeof(pxa_boot_img_hdr));
} else if (memcmp(((boot_img_hdr*) head)->cmdline, NOOKHD_MAGIC, 12) == 0
|| memcmp(((boot_img_hdr*) head)->cmdline, NOOKHD_NEW_MAGIC, 26) == 0) {
boot->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) {
boot->flags |= ACCLAIM_FLAG;
fprintf(stderr, "ACCLAIM_BAUWKSBOOT\n");
head += ACCLAIM_PRE_HEADER_SZ - 1;
continue;
} else {
boot->hdr = malloc(sizeof(boot_img_hdr));
memcpy(boot->hdr, head, sizeof(boot_img_hdr));
}
pos += header(boot, page_size);
for (int i = SHA_DIGEST_SIZE; i < SHA256_DIGEST_SIZE; ++i) {
if (header(boot, id)[i]) {
boot->flags |= SHA256_FLAG;
break;
}
}
print_hdr(boot);
boot->kernel = head + pos;
pos += header(boot, kernel_size);
pos_align();
boot->ramdisk = head + pos;
pos += header(boot, ramdisk_size);
pos_align();
boot->second = head + pos;
pos += header(boot, second_size);
pos_align();
boot->extra = head + pos;
pos += header(boot, extra_size);
pos_align();
if (pos < boot->map_size) {
boot->tail = head + pos;
boot->tail_size = boot->map_size - pos;
}
// Check tail info, currently only for LG Bump and Samsung SEANDROIDENFORCE
if (boot->tail_size >= 16 && memcmp(boot->tail, SEANDROID_MAGIC, 16) == 0) {
boot->flags |= SEANDROID_FLAG;
} else if (boot->tail_size >= 16 && memcmp(boot->tail, LG_BUMP_MAGIC, 16) == 0) {
boot->flags |= LG_BUMP_FLAG;
}
// Search for dtb in kernel
for (uint32_t i = 0; i < header(boot, kernel_size); ++i) {
if (memcmp(boot->kernel + i, DTB_MAGIC, 4) == 0) {
boot->dtb = boot->kernel + i;
boot->dt_size = header(boot, kernel_size) - i;
lheader(boot, kernel_size, = i);
fprintf(stderr, "DTB [%u]\n", boot->dt_size);
break;
}
}
boot->k_fmt = check_fmt(boot->kernel, header(boot, kernel_size));
boot->r_fmt = check_fmt(boot->ramdisk, header(boot, ramdisk_size));
// Check MTK
if (boot->k_fmt == MTK) {
fprintf(stderr, "MTK_KERNEL_HDR\n");
boot->flags |= MTK_KERNEL;
boot->k_hdr = malloc(sizeof(mtk_hdr));
memcpy(boot->k_hdr, boot->kernel, sizeof(mtk_hdr));
fprintf(stderr, "KERNEL [%u]\n", boot->k_hdr->size);
fprintf(stderr, "NAME [%s]\n", boot->k_hdr->name);
boot->kernel += 512;
lheader(boot, kernel_size, -= 512);
boot->k_fmt = check_fmt(boot->kernel, header(boot, kernel_size));
}
if (boot->r_fmt == MTK) {
fprintf(stderr, "MTK_RAMDISK_HDR\n");
boot->flags |= MTK_RAMDISK;
boot->r_hdr = malloc(sizeof(mtk_hdr));
memcpy(boot->r_hdr, boot->ramdisk, sizeof(mtk_hdr));
fprintf(stderr, "RAMDISK [%u]\n", boot->r_hdr->size);
fprintf(stderr, "NAME [%s]\n", boot->r_hdr->name);
boot->ramdisk += 512;
lheader(boot, ramdisk_size, -= 512);
boot->r_fmt = check_fmt(boot->ramdisk, header(boot, ramdisk_size));
}
char fmt[16];
get_fmt_name(boot->k_fmt, fmt);
fprintf(stderr, "KERNEL_FMT [%s]\n", fmt);
get_fmt_name(boot->r_fmt, fmt);
fprintf(stderr, "RAMDISK_FMT [%s]\n", fmt);
return boot->flags & CHROMEOS_FLAG ? CHROMEOS_RET :
((is_blk && boot->tail_size < 500 * 1024) ? INSUF_BLOCK_RET : 0);
default:
continue;
}
}
LOGE("No boot image magic found!\n");
}
int unpack(const char *image) {
boot_img boot;
int ret = parse_img(image, &boot);
int fd;
// Dump kernel
if (COMPRESSED(boot.k_fmt)) {
fd = creat(KERNEL_FILE, 0644);
decomp(boot.k_fmt, fd, boot.kernel, header(&boot, kernel_size));
close(fd);
} else {
dump(boot.kernel, header(&boot, 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);
decomp(boot.r_fmt, fd, boot.ramdisk, header(&boot, ramdisk_size));
close(fd);
} else {
dump(boot.ramdisk, header(&boot, ramdisk_size), RAMDISK_FILE);
}
// Dump second
dump(boot.second, header(&boot, second_size), SECOND_FILE);
// Dump extra
dump(boot.extra, header(&boot, extra_size), EXTRA_FILE);
clean_boot(&boot);
return ret;
}
#define file_align() write_zero(fd, align_off(lseek(fd, 0, SEEK_CUR) - header_off, header(&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
parse_img(orig_image, &boot);
// Reset all sizes
lheader(&boot, kernel_size, = 0);
lheader(&boot, ramdisk_size, = 0);
lheader(&boot, second_size, = 0);
lheader(&boot, extra_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, header(&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);
lheader(&boot, kernel_size, = comp(boot.k_fmt, fd, kernel_raw, raw_size));
munmap(kernel_raw, raw_size);
} else {
lheader(&boot, kernel_size, = restore(KERNEL_FILE, fd));
}
}
// dtb
if (access(DTB_FILE, R_OK) == 0) {
lheader(&boot, 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);
lheader(&boot, ramdisk_size, = comp(boot.r_fmt, fd, cpio, cpio_size));
munmap(cpio, cpio_size);
} else {
lheader(&boot, ramdisk_size, = restore(RAMDISK_FILE, fd));
}
file_align();
}
// second
second_off = lseek(fd, 0, SEEK_CUR);
if (access(SECOND_FILE, R_OK) == 0) {
lheader(&boot, second_size, = restore(SECOND_FILE, fd));
file_align();
}
// extra
extra_off = lseek(fd, 0, SEEK_CUR);
if (access(EXTRA_FILE, R_OK) == 0) {
lheader(&boot, extra_size, = restore(EXTRA_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, &boot.map_addr, &boot.map_size);
// MTK headers
if (boot.flags & MTK_KERNEL) {
boot.k_hdr->size = header(&boot, kernel_size);
lheader(&boot, kernel_size, += 512);
memcpy(boot.map_addr + kernel_off, boot.k_hdr, sizeof(mtk_hdr));
}
if (boot.flags & MTK_RAMDISK) {
boot.r_hdr->size = header(&boot, ramdisk_size);
lheader(&boot, 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 = header(&boot, kernel_size);
HASH_update(&ctx, boot.map_addr + kernel_off, size);
HASH_update(&ctx, &size, sizeof(size));
size = header(&boot, ramdisk_size);
HASH_update(&ctx, boot.map_addr + ramdisk_off, size);
HASH_update(&ctx, &size, sizeof(size));
size = header(&boot, second_size);
HASH_update(&ctx, boot.map_addr + second_off, size);
HASH_update(&ctx, &size, sizeof(size));
size = header(&boot, extra_size);
if (size) {
HASH_update(&ctx, boot.map_addr + extra_off, size);
HASH_update(&ctx, &size, sizeof(size));
}
memset(header(&boot, id), 0, 32);
memcpy(header(&boot, id), HASH_final(&ctx),
(boot.flags & SHA256_FLAG) ? SHA256_DIGEST_SIZE : SHA_DIGEST_SIZE);
// Print new image info
print_hdr(&boot);
// Main header
memcpy(boot.map_addr + header_off, boot.hdr,
(boot.flags & PXA_FLAG) ? sizeof(pxa_boot_img_hdr) : sizeof(boot_img_hdr));
if (boot.flags & DHTB_FLAG) {
// DHTB header
dhtb_hdr *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));
}
clean_boot(&boot);
}
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