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Adding DEK to private keys.

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Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
This commit is contained in:
Pol Henarejos
2022-04-27 20:16:21 +02:00
parent 06745515eb
commit 193220e59e
3 changed files with 83 additions and 10 deletions
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87
src/openpgp/openpgp.c
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@@ -30,7 +30,9 @@
bool has_pw1 = false;
bool has_pw2 = false;
bool has_pw3 = false;
uint8_t session_pw1[32];
uint8_t session_pw3[32];
static uint8_t dek[IV_SIZE+32];
uint8_t openpgp_aid[] = {
6,
@@ -186,9 +188,72 @@ void scan_files() {
flash_write_data_to_file(ef, def, sizeof(def));
}
}
if ((ef = search_by_fid(EF_DEK, NULL, SPECIFY_ANY))) {
if (!ef->data) {
TU_LOG1("DEK is empty\r\n");
const uint8_t def1[6] = { 0x31,0x32,0x33,0x34,0x35,0x36 };
const uint8_t def3[8] = { 0x31,0x32,0x33,0x34,0x35,0x36,0x37,0x38 };
uint8_t def[IV_SIZE+32+32];
const uint8_t *dek = random_bytes_get(IV_SIZE+32);
memcpy(def, dek, IV_SIZE+32);
memcpy(def+IV_SIZE+32, dek+IV_SIZE, 32);
hash_multi(def1, sizeof(def1), session_pw1);
aes_encrypt_cfb_256(session_pw1, def, def+IV_SIZE, 32);
memset(session_pw1, 0, sizeof(session_pw1));
hash_multi(def3, sizeof(def3), session_pw3);
aes_encrypt_cfb_256(session_pw3, def, def+IV_SIZE+32, 32);
memset(session_pw1, 0, sizeof(session_pw1));
flash_write_data_to_file(ef, def, sizeof(def));
}
}
low_flash_available();
}
int load_dek() {
if (!has_pw1 && !has_pw2 && !has_pw3)
return CCID_NO_LOGIN;
file_t *tf = search_by_fid(EF_DEK, NULL, SPECIFY_EF);
if (!tf)
return CCID_ERR_FILE_NOT_FOUND;
int r = CCID_OK;
if (has_pw1 || has_pw2) {
memcpy(dek, file_read(tf->data+sizeof(uint16_t)), IV_SIZE+32);
r = aes_decrypt_cfb_256(session_pw1, dek, dek+IV_SIZE, 32);
}
else if (has_pw3) {
memcpy(dek, file_read(tf->data+sizeof(uint16_t)), IV_SIZE);
memcpy(dek+IV_SIZE, file_read(tf->data+sizeof(uint16_t)+IV_SIZE+32), 32);
r = aes_decrypt_cfb_256(session_pw3, dek, dek+IV_SIZE, 32);
}
if (r != 0)
return CCID_EXEC_ERROR;
return CCID_OK;
}
void release_dek() {
memset(dek, 0, sizeof(dek));
}
int dek_encrypt(uint8_t *data, size_t len) {
int r;
if ((r = load_dek()) != CCID_OK)
return r;
r = aes_encrypt_cfb_256(dek+IV_SIZE, dek, data, len);
release_dek();
return r;
}
int dek_decrypt(uint8_t *data, size_t len) {
int r;
if ((r = load_dek()) != CCID_OK)
return r;
r = aes_decrypt_cfb_256(dek+IV_SIZE, dek, data, len);
release_dek();
return r;
}
void init_openpgp() {
isUserAuthenticated = false;
has_pw1 = has_pw3 = false;
@@ -707,6 +772,7 @@ int check_pin(const file_t *pin, const uint8_t *data, size_t len) {
has_pw1 = true;
else
has_pw2 = true;
hash_multi(data, len, session_pw1);
}
else if (pin->fid == EF_PW3) {
has_pw3 = true;
@@ -869,6 +935,10 @@ int store_keys(void *key_ctx, int type, uint16_t key_id) {
key_size = 32;
memcpy(kdata, key_ctx, key_size);
}
r = dek_encrypt(kdata, key_size);
if (r != CCID_OK) {
return r;
}
//r = aes_encrypt_cfb_256(file_read(pw3->data+2), session_pw3, kdata, key_size);
//if (r != CCID_OK)
// return r;
@@ -883,15 +953,10 @@ int load_private_key_rsa(mbedtls_rsa_context *ctx, file_t *fkey) {
//wait_button();
int key_size = file_read_uint16(fkey->data);
uint8_t kdata[4096/8];
//if (!has_pw3)
// return CCID_NO_LOGIN;
//file_t *pw3 = search_by_fid(EF_PW3, NULL, SPECIFY_EF);
//if (!pw3)
// return CCID_ERR_FILE_NOT_FOUND;
memcpy(kdata, file_read(fkey->data+2), key_size);
//int r = aes_decrypt_cfb_256(file_read(pw3->data+2), session_pw3, kdata, key_size);
//if (r != CCID_OK)
// return r;
if (dek_decrypt(kdata, key_size) != 0) {
return SW_EXEC_ERROR();
}
if (mbedtls_mpi_read_binary(&ctx->P, kdata, key_size/2) != 0) {
mbedtls_rsa_free(ctx);
return CCID_WRONG_DATA;
@@ -924,6 +989,9 @@ int load_private_key_ecdsa(mbedtls_ecdsa_context *ctx, file_t *fkey) {
int key_size = file_read_uint16(fkey->data);
uint8_t kdata[67]; //Worst case, 521 bit + 1byte
memcpy(kdata, file_read(fkey->data+2), key_size);
if (dek_decrypt(kdata, key_size) != 0) {
return SW_EXEC_ERROR();
}
mbedtls_ecp_group_id gid = kdata[0];
int r = mbedtls_ecp_read_key(gid, ctx, kdata+1, key_size-1);
if (r != 0) {
@@ -1241,6 +1309,9 @@ static int cmd_pso() {
if (len != 2*key_size-1)
return SW_WRONG_LENGTH();
memcpy(kdata, file_read(ef->data+2), key_size);
if (dek_decrypt(kdata, key_size) != 0) {
return SW_EXEC_ERROR();
}
mbedtls_ecdh_init(&ctx);
mbedtls_ecp_group_id gid = kdata[0];
r = mbedtls_ecdh_setup(&ctx, gid);