static void build_header(void)
{
u32 i;
memset(hdr, 0, sizeof hdr);
memcpy(hdr, "SCEUF\0\0\0", 8);
wbe64(hdr + 0x08, 1);
wbe64(hdr + 0x10, 0xf411);
wbe64(hdr + 0x18, n_files);
wbe64(hdr + 0x20, 0x50 + n_files * 0x40);
wbe64(hdr + 0x28, data_size);
for (i = 0; i < n_files; i++) {
wbe64(hdr + 0x30 + 0x20 * i + 0x00, files[i].id);
wbe64(hdr + 0x30 + 0x20 * i + 0x08, files[i].offset);
wbe64(hdr + 0x30 + 0x20 * i + 0x10, files[i].len);
wbe64(hdr + 0x30 + 0x20 * i + 0x18, 0);
wbe64(hdr + 0x30 + 0x20 * n_files + 0x20 * i, i);
calc_hmac(files[i].ptr, files[i].len,
hdr + 0x30 + 0x20 * n_files + 0x20 * i + 0x08);
}
calc_hmac(hdr, 0x30 + 0x40 * n_files,
hdr + 0x30 + 0x40 * n_files);
}
static int datablob_hmac_append(struct encrypted_key_payload *epayload,
const u8 *master_key, size_t master_keylen)
{
u8 derived_key[HASH_SIZE];
u8 *digest;
int ret;
ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
if (ret < 0)
goto out;
digest = epayload->format + epayload->datablob_len;
ret = calc_hmac(digest, derived_key, sizeof derived_key,
epayload->format, epayload->datablob_len);
if (!ret)
dump_hmac(NULL, digest, HASH_SIZE);
out:
return ret;
}
/* test HMAC
*/
int verify_hmac(const void *data, size_t datalen,
int hid, unsigned char *hmac, char *key, int keylen)
{
unsigned char *our_hmac;
int rc;
our_hmac = malloc(gcry_md_get_algo_dlen(hid));
if (!our_hmac)
return -1;
rc = calc_hmac(data, datalen, hid, our_hmac, key, keylen);
if (rc)
goto out_free;
rc = memcmp(our_hmac, hmac, gcry_md_get_algo_dlen(hid));
out_free:
if (our_hmac)
free(our_hmac);
return rc;
}
/* verify HMAC before decrypting encrypted key */
static int datablob_hmac_verify(struct encrypted_key_payload *epayload,
const u8 *format, const u8 *master_key,
size_t master_keylen)
{
u8 derived_key[HASH_SIZE];
u8 digest[HASH_SIZE];
int ret;
char *p;
unsigned short len;
ret = get_derived_key(derived_key, AUTH_KEY, master_key, master_keylen);
if (ret < 0)
goto out;
len = epayload->datablob_len;
if (!format) {
p = epayload->master_desc;
len -= strlen(epayload->format) + 1;
} else
p = epayload->format;
ret = calc_hmac(digest, derived_key, sizeof derived_key, p, len);
if (ret < 0)
goto out;
ret = memcmp(digest, epayload->format + epayload->datablob_len,
sizeof digest);
if (ret) {
ret = -EINVAL;
dump_hmac("datablob",
epayload->format + epayload->datablob_len,
HASH_SIZE);
dump_hmac("calc", digest, HASH_SIZE);
}
out:
return ret;
}
