120 lines
3.4 KiB
C
120 lines
3.4 KiB
C
#include <linux/fs.h>
|
|
|
|
#include "apk_sign.h"
|
|
#include "klog.h"
|
|
|
|
static int check_v2_signature(char* path, unsigned expected_size, unsigned expected_hash) {
|
|
unsigned char buffer[0x11] = {0};
|
|
u32 size4;
|
|
u64 size8, size_of_block;
|
|
|
|
loff_t pos;
|
|
|
|
int sign = -1;
|
|
struct file* fp = filp_open(path, O_RDONLY, 0);
|
|
if (IS_ERR(fp)) {
|
|
pr_err("open %s error.", path);
|
|
return PTR_ERR(fp);
|
|
}
|
|
|
|
sign = 1;
|
|
// https://en.wikipedia.org/wiki/Zip_(file_format)#End_of_central_directory_record_(EOCD)
|
|
for (int i = 0;; ++i) {
|
|
unsigned short n;
|
|
pos = generic_file_llseek(fp, -i - 2, SEEK_END);
|
|
kernel_read(fp, &n, 2, &pos);
|
|
if (n == i) {
|
|
pos -= 22;
|
|
kernel_read(fp, &size4, 4, &pos);
|
|
if ((size4 ^ 0xcafebabeu) == 0xccfbf1eeu) {
|
|
break;
|
|
}
|
|
}
|
|
if (i == 0xffff) {
|
|
pr_info("error: cannot find eocd\n");
|
|
goto clean;
|
|
}
|
|
}
|
|
|
|
pos += 12;
|
|
// offset
|
|
kernel_read(fp, &size4, 0x4, &pos);
|
|
pos = size4 - 0x18;
|
|
|
|
kernel_read(fp, &size8, 0x8, &pos);
|
|
kernel_read(fp, buffer, 0x10, &pos);
|
|
if (strcmp((char *) buffer, "APK Sig Block 42")) {
|
|
goto clean;
|
|
}
|
|
|
|
pos = size4 - (size8 + 0x8);
|
|
kernel_read(fp, &size_of_block, 0x8, &pos);
|
|
if (size_of_block != size8) {
|
|
goto clean;
|
|
}
|
|
|
|
for (;;) {
|
|
uint32_t id;
|
|
uint32_t offset;
|
|
kernel_read(fp, &size8, 0x8, &pos); // sequence length
|
|
if (size8 == size_of_block) {
|
|
break;
|
|
}
|
|
kernel_read(fp, &id, 0x4, &pos); // id
|
|
offset = 4;
|
|
pr_info("id: 0x%08x\n", id);
|
|
if ((id ^ 0xdeadbeefu) == 0xafa439f5u || (id ^ 0xdeadbeefu) == 0x2efed62f) {
|
|
kernel_read(fp, &size4, 0x4, &pos); // signer-sequence length
|
|
kernel_read(fp, &size4, 0x4, &pos); // signer length
|
|
kernel_read(fp, &size4, 0x4, &pos); // signed data length
|
|
offset += 0x4 * 3;
|
|
|
|
kernel_read(fp, &size4, 0x4, &pos); // digests-sequence length
|
|
pos += size4;
|
|
offset += 0x4 + size4;
|
|
|
|
kernel_read(fp, &size4, 0x4, &pos); // certificates length
|
|
kernel_read(fp, &size4, 0x4, &pos); // certificate length
|
|
offset += 0x4 * 2;
|
|
#if 0
|
|
int hash = 1;
|
|
signed char c;
|
|
for (unsigned i = 0; i < size4; ++i) {
|
|
kernel_read(fp, &c, 0x1, &pos);
|
|
hash = 31 * hash + c;
|
|
}
|
|
offset += size4;
|
|
pr_info(" size: 0x%04x, hash: 0x%08x\n", size4, ((unsigned) hash) ^ 0x14131211u);
|
|
#else
|
|
if (size4 == expected_size) {
|
|
int hash = 1;
|
|
signed char c;
|
|
for (unsigned i = 0; i < size4; ++i) {
|
|
kernel_read(fp, &c, 0x1, &pos);
|
|
hash = 31 * hash + c;
|
|
}
|
|
offset += size4;
|
|
if ((((unsigned) hash) ^ 0x14131211u) == expected_hash) {
|
|
sign = 0;
|
|
break;
|
|
}
|
|
}
|
|
// don't try again.
|
|
break;
|
|
#endif
|
|
}
|
|
pos += (size8 - offset);
|
|
}
|
|
|
|
clean:
|
|
filp_close(fp, 0);
|
|
|
|
return sign;
|
|
}
|
|
|
|
#define EXPECTED_SIZE 0x033b
|
|
#define EXPECTED_HASH 0xb0b91415
|
|
|
|
int is_manager_apk(char* path) {
|
|
return check_v2_signature(path, EXPECTED_SIZE, EXPECTED_HASH);
|
|
} |