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whitebox patch u2f not tested

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This commit is contained in:
Conor Patrick 2018-05-26 12:51:56 -04:00
parent aaa2257716
commit 0c9c52afc2
4 changed files with 124 additions and 67 deletions
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4
ctap_device.c
View File

@ -63,3 +63,7 @@ int ctap_generate_rng(uint8_t * dst, size_t num)
return 1; return 1;
} }

23
ctaphid.c
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@ -5,6 +5,7 @@
#include "ctaphid.h" #include "ctaphid.h"
#include "ctap.h" #include "ctap.h"
#include "u2f.h"
#include "time.h" #include "time.h"
#include "util.h" #include "util.h"
@ -447,6 +448,28 @@ start_over:
ctaphid_write(&wb, NULL, 0); ctaphid_write(&wb, NULL, 0);
break; break;
case CTAPHID_MSG:
printf("CTAPHID_CBOR\n");
if (buffer_len() == 0)
{
printf("Error,invalid 0 length field for MSG/U2F packet\n");
ctaphid_send_error(pkt->cid, ERR_INVALID_LEN);
ctaphid_init();
return;
}
ctaphid_write_buffer_init(&wb);
u2f_request(ctap_buffer);
wb.cid = active_cid;
wb.cmd = CTAPHID_CBOR;
wb.bcnt = (ctap_resp.length+1);
ctaphid_write(&wb, &status, 1);
ctaphid_write(&wb, ctap_resp.data, ctap_resp.length);
ctaphid_write(&wb, NULL, 0);
break;
default: default:
printf("error, unimplemented HID cmd: %02x\r\n", buffer_cmd()); printf("error, unimplemented HID cmd: %02x\r\n", buffer_cmd());
break; break;

154
u2f.c
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@ -1,7 +1,6 @@
#include "u2f.h" #include "u2f.h"
#include "ctap.h" #include "ctap.h"
#include "crypto.h" #include "crypto.h"
#if 0
// void u2f_response_writeback(uint8_t * buf, uint8_t len); // void u2f_response_writeback(uint8_t * buf, uint8_t len);
static int16_t u2f_register(struct u2f_register_request * req); static int16_t u2f_register(struct u2f_register_request * req);
@ -13,11 +12,9 @@ void u2f_request(struct u2f_request_apdu * req)
uint16_t * rcode = (uint16_t *)req; uint16_t * rcode = (uint16_t *)req;
uint32_t len = ((req->LC3) | ((uint32_t)req->LC2 << 8) | ((uint32_t)req->LC1 << 16)); uint32_t len = ((req->LC3) | ((uint32_t)req->LC2 << 8) | ((uint32_t)req->LC1 << 16));
u2f_response_start();
if (req->cla != 0) if (req->cla != 0)
{ {
u2f_hid_set_len(2); u2f_response_set_length(2);
*rcode = U2F_SW_CLASS_NOT_SUPPORTED; *rcode = U2F_SW_CLASS_NOT_SUPPORTED;
goto end; goto end;
} }
@ -27,7 +24,7 @@ void u2f_request(struct u2f_request_apdu * req)
case U2F_REGISTER: case U2F_REGISTER:
if (len != 64) if (len != 64)
{ {
u2f_hid_set_len(2); u2f_response_set_length(2);
*rcode = U2F_SW_WRONG_LENGTH; *rcode = U2F_SW_WRONG_LENGTH;
} }
else else
@ -41,7 +38,7 @@ void u2f_request(struct u2f_request_apdu * req)
case U2F_VERSION: case U2F_VERSION:
if (len) if (len)
{ {
u2f_hid_set_len(2); u2f_response_set_length(2);
*rcode = U2F_SW_WRONG_LENGTH; *rcode = U2F_SW_WRONG_LENGTH;
} }
else else
@ -54,7 +51,7 @@ void u2f_request(struct u2f_request_apdu * req)
*rcode = U2F_SW_NO_ERROR; *rcode = U2F_SW_NO_ERROR;
break; break;
default: default:
u2f_hid_set_len(2); u2f_response_set_length(2);
*rcode = U2F_SW_INS_NOT_SUPPORTED; *rcode = U2F_SW_INS_NOT_SUPPORTED;
break; break;
} }
@ -64,6 +61,27 @@ end:
u2f_response_flush(); u2f_response_flush();
} }
void u2f_response_writeback(const uint8_t * buf, uint16_t len)
{
}
// Set total length of U2F response. Must be done before any writebacks
extern void u2f_response_set_length(uint16_t len)
{
}
// u2f_response_flush callback when u2f finishes and will
// indicate when all buffer data, if any, should be written
extern void u2f_response_flush()
{
}
static uint8_t get_signature_length(uint8_t * sig) static uint8_t get_signature_length(uint8_t * sig)
{ {
return 0x46 + ((sig[32] & 0x80) == 0x80) + ((sig[0] & 0x80) == 0x80); return 0x46 + ((sig[32] & 0x80) == 0x80) + ((sig[0] & 0x80) == 0x80);
@ -99,41 +117,55 @@ static void dump_signature_der(uint8_t * sig)
// S value // S value
u2f_response_writeback(sig+32, 32); u2f_response_writeback(sig+32, 32);
} }
static int8_t u2f_load_key(struct u2f_key_handle * kh, uint8_t * appid)
int8_t u2f_appid_eq(struct u2f_key_handle * kh, uint8_t * appid)
{ {
crypto_ecc256_load_key((uint8_t*)kh, U2F_KEY_HANDLE_SIZE, appid, U2F_APPLICATION_SIZE);
return 0; return 0;
} }
int8_t u2f_load_key(struct u2f_key_handle * kh, uint8_t * appid) static void u2f_make_auth_tag(struct u2f_key_handle * kh, uint8_t * appid, uint8_t * tag)
{
crypto_ecc256_load_key(kh->key, U2F_KEY_HANDLE_KEY_SIZE, appid, U2F_APPLICATION_SIZE);
return 0;
}
void u2f_make_auth_tag(struct u2f_key_handle * kh, uint8_t * appid, uint8_t * tag)
{ {
uint8_t hashbuf[32]; uint8_t hashbuf[32];
crypto_sha256_hmac_init(NULL, 0, hashbuf); crypto_sha256_hmac_init(CRYPTO_MASTER_KEY, 0, hashbuf);
crypto_sha256_update(kh->key, U2F_KEY_HANDLE_KEY_SIZE); crypto_sha256_update(kh->key, U2F_KEY_HANDLE_KEY_SIZE);
crypto_sha256_update(appid, ); crypto_sha256_update(appid, U2F_APPLICATION_SIZE);
crypto_sha256_hmac_final(hashbuf); crypto_sha256_hmac_final(CRYPTO_MASTER_KEY, 0,hashbuf);
memmove(tag, hashbuf, CREDENTIAL_TAG_SIZE); memmove(tag, hashbuf, CREDENTIAL_TAG_SIZE);
} }
static int8_t u2f_appid_eq(struct u2f_key_handle * kh, uint8_t * appid)
{
uint8_t tag[U2F_KEY_HANDLE_TAG_SIZE];
u2f_make_auth_tag(kh, appid, kh->tag);
if (memcmp(kh->tag, tag, U2F_KEY_HANDLE_TAG_SIZE) == 0)
return 0;
else
return -1;
}
static int8_t u2f_new_keypair(struct u2f_key_handle * kh, uint8_t * appid, uint8_t * pubkey)
{
ctap_generate_rng(kh->key, U2F_KEY_HANDLE_KEY_SIZE);
u2f_make_auth_tag(kh, appid, kh->tag);
crypto_ecc256_derive_public_key((uint8_t*)kh, U2F_KEY_HANDLE_SIZE, pubkey, pubkey+32);
return 0;
}
static int16_t u2f_authenticate(struct u2f_authenticate_request * req, uint8_t control) static int16_t u2f_authenticate(struct u2f_authenticate_request * req, uint8_t control)
{ {
uint8_t up = 1; uint8_t up = 1;
uint32_t count; uint32_t count;
uint8_t hash[32];
uint8_t * sig = (uint8_t*)req;
if (control == U2F_AUTHENTICATE_CHECK) if (control == U2F_AUTHENTICATE_CHECK)
{ {
u2f_hid_set_len(2); u2f_response_set_length(2);
if (u2f_appid_eq(&req->kh, req->app) == 0) if (u2f_appid_eq(&req->kh, req->app) == 0)
{ {
return U2F_SW_CONDITIONS_NOT_SATISFIED; return U2F_SW_CONDITIONS_NOT_SATISFIED;
@ -151,38 +183,37 @@ static int16_t u2f_authenticate(struct u2f_authenticate_request * req, uint8_t c
) )
{ {
u2f_hid_set_len(2); u2f_response_set_length(2);
return U2F_SW_WRONG_PAYLOAD; return U2F_SW_WRONG_PAYLOAD;
} }
if (u2f_get_user_feedback()) if (ctap_user_presence_test())
{ {
u2f_hid_set_len(2); u2f_response_set_length(2);
return U2F_SW_CONDITIONS_NOT_SATISFIED; return U2F_SW_CONDITIONS_NOT_SATISFIED;
} }
count = u2f_count(); count = ctap_atomic_count(0);
u2f_sha256_start(); crypto_sha256_init();
u2f_sha256_update(req->app,32);
u2f_sha256_update(&up,1);
u2f_sha256_update((uint8_t *)&count,4);
u2f_sha256_update(req->chal,32);
u2f_sha256_finish(); crypto_sha256_update(req->app,32);
crypto_sha256_update(&up,1);
crypto_sha256_update((uint8_t *)&count,4);
crypto_sha256_update(req->chal,32);
if (u2f_ecdsa_sign((uint8_t*)req, req->kh, req->app) == -1) crypto_sha256_final(hash);
{
return U2F_SW_WRONG_DATA+0x20;
}
u2f_hid_set_len(7 + get_signature_length((uint8_t*)req)); crypto_ecc256_sign(hash, 32, sig);
u2f_response_set_length(7 + get_signature_length(sig));
u2f_response_writeback(&up,1); u2f_response_writeback(&up,1);
u2f_response_writeback((uint8_t *)&count,4); u2f_response_writeback((uint8_t *)&count,4);
dump_signature_der((uint8_t*)req); dump_signature_der(sig);
return U2F_SW_NO_ERROR; return U2F_SW_NO_ERROR;
} }
@ -191,49 +222,49 @@ static int16_t u2f_register(struct u2f_register_request * req)
{ {
uint8_t i[] = {0x0,U2F_EC_FMT_UNCOMPRESSED}; uint8_t i[] = {0x0,U2F_EC_FMT_UNCOMPRESSED};
uint8_t key_handle[U2F_KEY_HANDLE_SIZE]; struct u2f_key_handle key_handle;
uint8_t pubkey[64]; uint8_t pubkey[64];
uint8_t hash[32];
uint8_t * sig = (uint8_t*)req;
const uint16_t attest_size = u2f_attestation_cert_size(); const uint16_t attest_size = attestation_cert_der_size;
if (u2f_get_user_feedback()) if (ctap_user_presence_test())
{ {
u2f_hid_set_len(2); u2f_response_set_length(2);
return U2F_SW_CONDITIONS_NOT_SATISFIED; return U2F_SW_CONDITIONS_NOT_SATISFIED;
} }
if ( u2f_new_keypair(key_handle, req->app, pubkey) == -1) if ( u2f_new_keypair(&key_handle, req->app, pubkey) == -1)
{ {
u2f_hid_set_len(2); u2f_response_set_length(2);
return U2F_SW_INSUFFICIENT_MEMORY; return U2F_SW_INSUFFICIENT_MEMORY;
} }
u2f_sha256_start(); crypto_sha256_init();
u2f_sha256_update(i,1); crypto_sha256_update(i,1);
u2f_sha256_update(req->app,32); crypto_sha256_update(req->app,32);
u2f_sha256_update(req->chal,32); crypto_sha256_update(req->chal,32);
u2f_sha256_update(key_handle,U2F_KEY_HANDLE_SIZE); crypto_sha256_update((uint8_t*)&key_handle,U2F_KEY_HANDLE_SIZE);
u2f_sha256_update(i+1,1); crypto_sha256_update(i+1,1);
u2f_sha256_update(pubkey,64); crypto_sha256_update(pubkey,64);
u2f_sha256_finish(); crypto_sha256_final(hash);
if (u2f_ecdsa_sign((uint8_t*)req, U2F_ATTESTATION_HANDLE, req->app) == -1) crypto_ecc256_load_attestation_key();
{ crypto_ecc256_sign(hash, 32, sig);
return U2F_SW_WRONG_DATA;
}
u2f_hid_set_len(69 + get_signature_length((uint8_t*)req) + U2F_KEY_HANDLE_SIZE + u2f_attestation_cert_size()); u2f_response_set_length(69 + get_signature_length((uint8_t*)req) + U2F_KEY_HANDLE_SIZE + attest_size);
i[0] = 0x5; i[0] = 0x5;
u2f_response_writeback(i,2); u2f_response_writeback(i,2);
u2f_response_writeback(pubkey,64); u2f_response_writeback(pubkey,64);
i[0] = U2F_KEY_HANDLE_SIZE; i[0] = U2F_KEY_HANDLE_SIZE;
u2f_response_writeback(i,1); u2f_response_writeback(i,1);
u2f_response_writeback(key_handle,U2F_KEY_HANDLE_SIZE); u2f_response_writeback((uint8_t*)&key_handle,U2F_KEY_HANDLE_SIZE);
u2f_response_writeback(u2f_get_attestation_cert(),u2f_attestation_cert_size()); u2f_response_writeback(attestation_cert_der,attest_size);
dump_signature_der((uint8_t*)req); dump_signature_der((uint8_t*)req);
@ -243,9 +274,8 @@ static int16_t u2f_register(struct u2f_register_request * req)
static int16_t u2f_version() static int16_t u2f_version()
{ {
code const char version[] = "U2F_V2"; const char version[] = "U2F_V2";
u2f_hid_set_len(2 + sizeof(version)-1); u2f_response_set_length(2 + sizeof(version)-1);
u2f_response_writeback(version, sizeof(version)-1); u2f_response_writeback(version, sizeof(version)-1);
return U2F_SW_NO_ERROR; return U2F_SW_NO_ERROR;
} }
#endif

10
u2f.h
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@ -11,7 +11,7 @@
#define U2F_CHALLENGE_SIZE 32 #define U2F_CHALLENGE_SIZE 32
#define U2F_APPLICATION_SIZE 32 #define U2F_APPLICATION_SIZE 32
#define U2F_KEY_HANDLE_TAG_SIZE 16 #define U2F_KEY_HANDLE_TAG_SIZE 16
#define U2F_KEY_HANDLE_KEY_SIZE 36 #define U2F_KEY_HANDLE_KEY_SIZE 32
#define U2F_KEY_HANDLE_SIZE (U2F_KEY_HANDLE_KEY_SIZE+U2F_KEY_HANDLE_TAG_SIZE) #define U2F_KEY_HANDLE_SIZE (U2F_KEY_HANDLE_KEY_SIZE+U2F_KEY_HANDLE_TAG_SIZE)
#define U2F_REGISTER_REQUEST_SIZE (U2F_CHALLENGE_SIZE+U2F_APPLICATION_SIZE) #define U2F_REGISTER_REQUEST_SIZE (U2F_CHALLENGE_SIZE+U2F_APPLICATION_SIZE)
#define U2F_MAX_REQUEST_PAYLOAD (1 + U2F_CHALLENGE_SIZE+U2F_APPLICATION_SIZE + 1 + U2F_KEY_HANDLE_SIZE) #define U2F_MAX_REQUEST_PAYLOAD (1 + U2F_CHALLENGE_SIZE+U2F_APPLICATION_SIZE + 1 + U2F_KEY_HANDLE_SIZE)
@ -99,14 +99,14 @@ void u2f_request(struct u2f_request_apdu* req);
// u2f_response_writeback callback for u2f to send back response data // u2f_response_writeback callback for u2f to send back response data
// @buf data to write back // @buf data to write back
// @len length of buf in bytes // @len length of buf in bytes
extern void u2f_response_writeback(uint8_t * buf, uint16_t len); extern void u2f_response_writeback(const uint8_t * buf, uint16_t len);
// Set total length of U2F response. Must be done before any writebacks
extern void u2f_response_set_length(uint16_t len);
// u2f_response_flush callback when u2f finishes and will // u2f_response_flush callback when u2f finishes and will
// indicate when all buffer data, if any, should be written // indicate when all buffer data, if any, should be written
extern void u2f_response_flush(); extern void u2f_response_flush();
// set_response_length method to set the total length of the response for use by underlying layer
// @len the length of U2F response in bytes
extern void set_response_length(uint16_t len);
#endif /* U2F_H_ */ #endif /* U2F_H_ */