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Minor refactoring

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This commit is contained in:
topjohnwu 2020-10-15 00:19:11 -07:00
parent 1edc4449d5
commit aaaaa3d044
2 changed files with 36 additions and 41 deletions
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76
native/jni/magiskboot/bootimg.cpp
View File

@ -193,16 +193,42 @@ boot_img::~boot_img() {
delete hdr;
}
static format_t check_fmt_lg(uint8_t *buf, unsigned size) {
format_t fmt = check_fmt(buf, size);
static int find_dtb_offset(uint8_t *buf, unsigned sz) {
for (int off = 0; off + sizeof(fdt_header) < sz; ++off) {
auto fdt_hdr = reinterpret_cast<fdt_header *>(buf + off);
if (fdt32_to_cpu(fdt_hdr->magic) != FDT_MAGIC)
continue;
// Check that fdt_header.totalsize does not overflow kernel image size
uint32_t totalsize = fdt32_to_cpu(fdt_hdr->totalsize);
if (totalsize + off > sz)
continue;
// Check that fdt_header.off_dt_struct does not overflow kernel image size
uint32_t off_dt_struct = fdt32_to_cpu(fdt_hdr->off_dt_struct);
if (off_dt_struct + off > sz)
continue;
// Check that fdt_node_header.tag of first node is FDT_BEGIN_NODE
auto fdt_node_hdr = reinterpret_cast<fdt_node_header *>(buf + off + off_dt_struct);
if (fdt32_to_cpu(fdt_node_hdr->tag) != FDT_BEGIN_NODE)
continue;
return off;
}
return -1;
}
static format_t check_fmt_lg(uint8_t *buf, unsigned sz) {
format_t fmt = check_fmt(buf, sz);
if (fmt == LZ4_LEGACY) {
// We need to check if it is LZ4_LG
unsigned off = 4;
unsigned block_sz;
while (off + sizeof(block_sz) <= size) {
while (off + sizeof(block_sz) <= sz) {
memcpy(&block_sz, buf + off, sizeof(block_sz));
off += sizeof(block_sz);
if (off + block_sz > size)
if (off + block_sz > sz)
return LZ4_LG;
off += block_sz;
}
@ -284,7 +310,12 @@ void boot_img::parse_image(uint8_t *addr) {
flags |= LG_BUMP_FLAG;
}
find_kernel_dtb();
if (int dtb_off = find_dtb_offset(kernel, hdr->kernel_size()); dtb_off > 0) {
kernel_dtb = kernel + dtb_off;
kernel_dt_size = hdr->kernel_size() - dtb_off;
hdr->kernel_size() = dtb_off;
fprintf(stderr, "%-*s [%u]\n", PADDING, "KERNEL_DTB", kernel_dt_size);
}
if (auto size = hdr->kernel_size()) {
k_fmt = check_fmt_lg(kernel, size);
@ -320,41 +351,6 @@ void boot_img::parse_image(uint8_t *addr) {
}
}
static int find_dtb_offset(uint8_t *buf, int sz) {
for (int off = 0; off < sz - (int) sizeof(fdt_header); ++off) {
auto fdt_hdr = reinterpret_cast<fdt_header *>(buf + off);
if (fdt32_to_cpu(fdt_hdr->magic) != FDT_MAGIC)
continue;
// Check that fdt_header.totalsize does not overflow kernel image size
uint32_t totalsize = fdt32_to_cpu(fdt_hdr->totalsize);
if (totalsize + off > sz)
continue;
// Check that fdt_header.off_dt_struct does not overflow kernel image size
uint32_t off_dt_struct = fdt32_to_cpu(fdt_hdr->off_dt_struct);
if (off_dt_struct + off > sz)
continue;
// Check that fdt_node_header.tag of first node is FDT_BEGIN_NODE
auto fdt_node_hdr = reinterpret_cast<fdt_node_header *>(buf + off + off_dt_struct);
if (fdt32_to_cpu(fdt_node_hdr->tag) != FDT_BEGIN_NODE)
continue;
return off;
}
return -1;
}
void boot_img::find_kernel_dtb() {
if (int off = find_dtb_offset(kernel, hdr->kernel_size()); off > 0) {
kernel_dtb = kernel + off;
kernel_dt_size = hdr->kernel_size() - off;
hdr->kernel_size() = off;
fprintf(stderr, "%-*s [%u]\n", PADDING, "KERNEL_DTB", kernel_dt_size);
}
}
int split_image_dtb(const char *filename) {
uint8_t *buf;
size_t sz;

1
native/jni/magiskboot/bootimg.hpp
View File

@ -384,5 +384,4 @@ struct boot_img {
~boot_img();
void parse_image(uint8_t *addr);
void find_kernel_dtb();
};