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add u2f shell

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This commit is contained in:
Conor Patrick 2018-05-26 11:36:41 -04:00
parent 52cc61a575
commit 7eceff2ffe
2 changed files with 363 additions and 0 deletions
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251
u2f.c Normal file
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#include "u2f.h"
#include "ctap.h"
#include "crypto.h"
#if 0
// void u2f_response_writeback(uint8_t * buf, uint8_t len);
static int16_t u2f_register(struct u2f_register_request * req);
static int16_t u2f_version();
static int16_t u2f_authenticate(struct u2f_authenticate_request * req, uint8_t control);
void u2f_request(struct u2f_request_apdu * req)
{
uint16_t * rcode = (uint16_t *)req;
uint32_t len = ((req->LC3) | ((uint32_t)req->LC2 << 8) | ((uint32_t)req->LC1 << 16));
u2f_response_start();
if (req->cla != 0)
{
u2f_hid_set_len(2);
*rcode = U2F_SW_CLASS_NOT_SUPPORTED;
goto end;
}
switch(req->ins)
{
case U2F_REGISTER:
if (len != 64)
{
u2f_hid_set_len(2);
*rcode = U2F_SW_WRONG_LENGTH;
}
else
{
*rcode = u2f_register((struct u2f_register_request*)req->payload);
}
break;
case U2F_AUTHENTICATE:
*rcode = u2f_authenticate((struct u2f_authenticate_request*)req->payload, req->p1);
break;
case U2F_VERSION:
if (len)
{
u2f_hid_set_len(2);
*rcode = U2F_SW_WRONG_LENGTH;
}
else
{
*rcode = u2f_version();
}
break;
case U2F_VENDOR_FIRST:
case U2F_VENDOR_LAST:
*rcode = U2F_SW_NO_ERROR;
break;
default:
u2f_hid_set_len(2);
*rcode = U2F_SW_INS_NOT_SUPPORTED;
break;
}
end:
u2f_response_writeback((uint8_t*)rcode,2);
u2f_response_flush();
}
static uint8_t get_signature_length(uint8_t * sig)
{
return 0x46 + ((sig[32] & 0x80) == 0x80) + ((sig[0] & 0x80) == 0x80);
}
static void dump_signature_der(uint8_t * sig)
{
uint8_t pad_s = (sig[32] & 0x80) == 0x80;
uint8_t pad_r = (sig[0] & 0x80) == 0x80;
uint8_t i[] = {0x30, 0x44};
i[1] += (pad_s + pad_r);
// DER encoded signature
// write der sequence
// has to be minimum distance and padded with 0x00 if MSB is a 1.
u2f_response_writeback(i,2);
i[1] = 0;
// length of R value plus 0x00 pad if necessary
u2f_response_writeback("\x02",1);
i[0] = 0x20 + pad_r;
u2f_response_writeback(i,1 + pad_r);
// R value
u2f_response_writeback(sig, 32);
// length of S value plus 0x00 pad if necessary
u2f_response_writeback("\x02",1);
i[0] = 0x20 + pad_s;
u2f_response_writeback(i,1 + pad_s);
// S value
u2f_response_writeback(sig+32, 32);
}
int8_t u2f_appid_eq(struct u2f_key_handle * kh, uint8_t * appid)
{
return 0;
}
int8_t u2f_load_key(struct u2f_key_handle * kh, uint8_t * appid)
{
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];
crypto_sha256_hmac_init(NULL, 0, hashbuf);
crypto_sha256_update(kh->key, U2F_KEY_HANDLE_KEY_SIZE);
crypto_sha256_update(appid, );
crypto_sha256_hmac_final(hashbuf);
memmove(tag, hashbuf, CREDENTIAL_TAG_SIZE);
}
static int16_t u2f_authenticate(struct u2f_authenticate_request * req, uint8_t control)
{
uint8_t up = 1;
uint32_t count;
if (control == U2F_AUTHENTICATE_CHECK)
{
u2f_hid_set_len(2);
if (u2f_appid_eq(&req->kh, req->app) == 0)
{
return U2F_SW_CONDITIONS_NOT_SATISFIED;
}
else
{
return U2F_SW_WRONG_DATA;
}
}
if (
control != U2F_AUTHENTICATE_SIGN ||
req->khl != U2F_KEY_HANDLE_SIZE ||
u2f_appid_eq(&req->kh, req->app) != 0 || // Order of checks is important
u2f_load_key(&req->kh, req->app) != 0
)
{
u2f_hid_set_len(2);
return U2F_SW_WRONG_PAYLOAD;
}
if (u2f_get_user_feedback())
{
u2f_hid_set_len(2);
return U2F_SW_CONDITIONS_NOT_SATISFIED;
}
count = u2f_count();
u2f_sha256_start();
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();
if (u2f_ecdsa_sign((uint8_t*)req, req->kh, req->app) == -1)
{
return U2F_SW_WRONG_DATA+0x20;
}
u2f_hid_set_len(7 + get_signature_length((uint8_t*)req));
u2f_response_writeback(&up,1);
u2f_response_writeback((uint8_t *)&count,4);
dump_signature_der((uint8_t*)req);
return U2F_SW_NO_ERROR;
}
static int16_t u2f_register(struct u2f_register_request * req)
{
uint8_t i[] = {0x0,U2F_EC_FMT_UNCOMPRESSED};
uint8_t key_handle[U2F_KEY_HANDLE_SIZE];
uint8_t pubkey[64];
const uint16_t attest_size = u2f_attestation_cert_size();
if (u2f_get_user_feedback())
{
u2f_hid_set_len(2);
return U2F_SW_CONDITIONS_NOT_SATISFIED;
}
if ( u2f_new_keypair(key_handle, req->app, pubkey) == -1)
{
u2f_hid_set_len(2);
return U2F_SW_INSUFFICIENT_MEMORY;
}
u2f_sha256_start();
u2f_sha256_update(i,1);
u2f_sha256_update(req->app,32);
u2f_sha256_update(req->chal,32);
u2f_sha256_update(key_handle,U2F_KEY_HANDLE_SIZE);
u2f_sha256_update(i+1,1);
u2f_sha256_update(pubkey,64);
u2f_sha256_finish();
if (u2f_ecdsa_sign((uint8_t*)req, U2F_ATTESTATION_HANDLE, req->app) == -1)
{
return U2F_SW_WRONG_DATA;
}
u2f_hid_set_len(69 + get_signature_length((uint8_t*)req) + U2F_KEY_HANDLE_SIZE + u2f_attestation_cert_size());
i[0] = 0x5;
u2f_response_writeback(i,2);
u2f_response_writeback(pubkey,64);
i[0] = U2F_KEY_HANDLE_SIZE;
u2f_response_writeback(i,1);
u2f_response_writeback(key_handle,U2F_KEY_HANDLE_SIZE);
u2f_response_writeback(u2f_get_attestation_cert(),u2f_attestation_cert_size());
dump_signature_der((uint8_t*)req);
return U2F_SW_NO_ERROR;
}
static int16_t u2f_version()
{
code const char version[] = "U2F_V2";
u2f_hid_set_len(2 + sizeof(version)-1);
u2f_response_writeback(version, sizeof(version)-1);
return U2F_SW_NO_ERROR;
}
#endif

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#ifndef _U2F_H_
#define _U2F_H_
#include <stdint.h>
#define U2F_EC_FMT_UNCOMPRESSED 0x04
#define U2F_EC_POINT_SIZE 32
#define U2F_EC_PUBKEY_SIZE 65
#define U2F_APDU_SIZE 7
#define U2F_CHALLENGE_SIZE 32
#define U2F_APPLICATION_SIZE 32
#define U2F_KEY_HANDLE_TAG_SIZE 16
#define U2F_KEY_HANDLE_KEY_SIZE 36
#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_MAX_REQUEST_PAYLOAD (1 + U2F_CHALLENGE_SIZE+U2F_APPLICATION_SIZE + 1 + U2F_KEY_HANDLE_SIZE)
// U2F native commands
#define U2F_REGISTER 0x01
#define U2F_AUTHENTICATE 0x02
#define U2F_VERSION 0x03
#define U2F_VENDOR_FIRST 0xc0
#define U2F_VENDOR_LAST 0xff
// U2F_CMD_REGISTER command defines
#define U2F_REGISTER_ID 0x05
#define U2F_REGISTER_HASH_ID 0x00
// U2F Authenticate
#define U2F_AUTHENTICATE_CHECK 0x7
#define U2F_AUTHENTICATE_SIGN 0x3
// Command status responses
#define U2F_SW_NO_ERROR 0x9000
#define U2F_SW_WRONG_DATA 0x6984
#define U2F_SW_CONDITIONS_NOT_SATISFIED 0x6985
#define U2F_SW_INS_NOT_SUPPORTED 0x6d00
#define U2F_SW_WRONG_LENGTH 0x6700
#define U2F_SW_CLASS_NOT_SUPPORTED 0x6E00
#define U2F_SW_WRONG_PAYLOAD 0x6a80
#define U2F_SW_INSUFFICIENT_MEMORY 0x9210
// Delay in milliseconds to wait for user input
#define U2F_MS_USER_INPUT_WAIT 3000
struct u2f_request_apdu
{
uint8_t cla;
uint8_t ins;
uint8_t p1;
uint8_t p2;
uint8_t LC1;
uint8_t LC2;
uint8_t LC3;
uint8_t payload[U2F_MAX_REQUEST_PAYLOAD];
};
struct u2f_ec_point
{
uint8_t fmt;
uint8_t x[U2F_EC_POINT_SIZE];
uint8_t y[U2F_EC_POINT_SIZE];
};
struct u2f_register_request
{
uint8_t chal[U2F_CHALLENGE_SIZE];
uint8_t app[U2F_APPLICATION_SIZE];
};
struct u2f_key_handle
{
uint8_t tag[U2F_KEY_HANDLE_TAG_SIZE];
uint8_t key[U2F_KEY_HANDLE_KEY_SIZE];
};
struct u2f_authenticate_request
{
uint8_t chal[U2F_CHALLENGE_SIZE];
uint8_t app[U2F_APPLICATION_SIZE];
uint8_t khl;
struct u2f_key_handle kh;
};
// u2f_request send a U2F message to U2F protocol
// @req U2F message
void u2f_request(struct u2f_request_apdu* req);
//////////////////////////////////////////////////////////////////
/* Platform specific functions that must be implemented by user */
//////////////////////////////////////////////////////////////////
// u2f_response_writeback callback for u2f to send back response data
// @buf data to write back
// @len length of buf in bytes
extern void u2f_response_writeback(uint8_t * buf, 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();
// 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_ */