/*
* Copyright (c) 2019 Markus Friedl
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "includes.h"
#ifdef ENABLE_SK_INTERNAL
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stddef.h>
#include <stdarg.h>
#ifdef WITH_OPENSSL
#include <openssl/opensslv.h>
#include <openssl/crypto.h>
#include <openssl/bn.h>
#include <openssl/ec.h>
#include <openssl/ecdsa.h>
#endif /* WITH_OPENSSL */
#include <fido.h>
#include <fido/credman.h>
#ifndef SK_STANDALONE
#include "log.h"
#include "xmalloc.h"
#endif
/* #define SK_DEBUG 1 */
#define MAX_FIDO_DEVICES 256
/* Compatibility with OpenSSH 1.0.x */
#if (OPENSSL_VERSION_NUMBER < 0x10100000L)
#define ECDSA_SIG_get0(sig, pr, ps) \
do { \
(*pr) = sig->r; \
(*ps) = sig->s; \
} while (0)
#endif
#define SK_VERSION_MAJOR 0x00040000 /* current API version */
/* Flags */
#define SK_USER_PRESENCE_REQD 0x01
#define SK_USER_VERIFICATION_REQD 0x04
#define SK_RESIDENT_KEY 0x20
/* Algs */
#define SK_ECDSA 0x00
#define SK_ED25519 0x01
/* Error codes */
#define SSH_SK_ERR_GENERAL -1
#define SSH_SK_ERR_UNSUPPORTED -2
#define SSH_SK_ERR_PIN_REQUIRED -3
struct sk_enroll_response {
uint8_t *public_key;
size_t public_key_len;
uint8_t *key_handle;
size_t key_handle_len;
uint8_t *signature;
size_t signature_len;
uint8_t *attestation_cert;
size_t attestation_cert_len;
};
struct sk_sign_response {
uint8_t flags;
uint32_t counter;
uint8_t *sig_r;
size_t sig_r_len;
uint8_t *sig_s;
size_t sig_s_len;
};
struct sk_resident_key {
uint32_t alg;
size_t slot;
char *application;
struct sk_enroll_response key;
};
struct sk_option {
char *name;
char *value;
uint8_t required;
};
/* If building as part of OpenSSH, then rename exported functions */
#if !defined(SK_STANDALONE)
#define sk_api_version ssh_sk_api_version
#define sk_enroll ssh_sk_enroll
#define sk_sign ssh_sk_sign
#define sk_load_resident_keys ssh_sk_load_resident_keys
#endif
/* Return the version of the middleware API */
uint32_t sk_api_version(void);
/* Enroll a U2F key (private key generation) */
int sk_enroll(uint32_t alg, const uint8_t *challenge, size_t challenge_len,
const char *application, uint8_t flags, const char *pin,
struct sk_option **options, struct sk_enroll_response **enroll_response);
/* Sign a challenge */
int sk_sign(uint32_t alg, const uint8_t *message, size_t message_len,
const char *application, const uint8_t *key_handle, size_t key_handle_len,
uint8_t flags, const char *pin, struct sk_option **options,
struct sk_sign_response **sign_response);
/* Load resident keys */
int sk_load_resident_keys(const char *pin, struct sk_option **options,
struct sk_resident_key ***rks, size_t *nrks);
static void skdebug(const char *func, const char *fmt, ...)
__attribute__((__format__ (printf, 2, 3)));
static void
skdebug(const char *func, const char *fmt, ...)
{
#if !defined(SK_STANDALONE)
char *msg;
va_list ap;
va_start(ap, fmt);
xvasprintf(&msg, fmt, ap);
va_end(ap);
debug("%s: %s", func, msg);
free(msg);
#elif defined(SK_DEBUG)
va_list ap;
va_start(ap, fmt);
fprintf(stderr, "%s: ", func);
vfprintf(stderr, fmt, ap);
fputc('\n', stderr);
va_end(ap);
#else
(void)func; /* XXX */
(void)fmt; /* XXX */
#endif
}
uint32_t
sk_api_version(void)
{
return