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openssh-portable/ssh-sk.c

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/* $OpenBSD: ssh-sk.c,v 1.29 2020/03/06 18:25:48 markus Exp $ */
/*
* Copyright (c) 2019 Google LLC
*
* 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.
*/
/* #define DEBUG_SK 1 */
#include "includes.h"
#ifdef ENABLE_SK
#include <dlfcn.h>
#include <stddef.h>
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#include <string.h>
#include <stdio.h>
#ifdef WITH_OPENSSL
#include <openssl/objects.h>
#include <openssl/ec.h>
#endif /* WITH_OPENSSL */
#include "log.h"
#include "misc.h"
#include "sshbuf.h"
#include "sshkey.h"
#include "ssherr.h"
#include "digest.h"
#include "ssh-sk.h"
#include "sk-api.h"
#include "crypto_api.h"
struct sshsk_provider {
char *path;
void *dlhandle;
/* Return the version of the middleware API */
uint32_t (*sk_api_version)(void);
/* Enroll a U2F key (private key generation) */
int (*sk_enroll)(int alg, const uint8_t *challenge,
size_t challenge_len, const char *application, uint8_t flags,
const char *pin, struct sk_option **opts,
struct sk_enroll_response **enroll_response);
/* Sign a challenge */
int (*sk_sign)(int 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 **opts,
struct sk_sign_response **sign_response);
/* Enumerate resident keys */
int (*sk_load_resident_keys)(const char *pin, struct sk_option **opts,
struct sk_resident_key ***rks, size_t *nrks);
};
/* Built-in version */
int ssh_sk_enroll(int alg, const uint8_t *challenge,
size_t challenge_len, const char *application, uint8_t flags,
const char *pin, struct sk_option **opts,
struct sk_enroll_response **enroll_response);
int ssh_sk_sign(int 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 **opts,
struct sk_sign_response **sign_response);
int ssh_sk_load_resident_keys(const char *pin, struct sk_option **opts,
struct sk_resident_key ***rks, size_t *nrks);
static void
sshsk_free(struct sshsk_provider *p)
{
if (p == NULL)
return;
free(p->path);
if (p->dlhandle != NULL)
dlclose(p->dlhandle);
free(p);
}
static struct sshsk_provider *
sshsk_open(const char *path)
{
struct sshsk_provider *ret = NULL;
uint32_t version;
if (path == NULL || *path == '\0') {
error("No FIDO SecurityKeyProvider specified");
return NULL;
}
if ((ret = calloc(1, sizeof(*ret))) == NULL) {
error("%s: calloc failed", __func__);
return NULL;
}
if ((ret->path = strdup(path)) == NULL) {
error("%s: strdup failed", __func__);
goto fail;
}
/* Skip the rest if we're using the linked in middleware */
if (strcasecmp(ret->path, "internal") == 0) {
#ifdef ENABLE_SK_INTERNAL
ret->sk_enroll = ssh_sk_enroll;
ret->sk_sign = ssh_sk_sign;
ret->sk_load_resident_keys = ssh_sk_load_resident_keys;
#else
error("internal security key support not enabled");
#endif
return ret;
}
if ((ret->dlhandle = dlopen(path, RTLD_NOW)) == NULL) {
error("Provider \"%s\" dlopen failed: %s", path, dlerror());
goto fail;
}
if ((ret->sk_api_version = dlsym(ret->dlhandle,
"sk_api_version")) == NULL) {
error("Provider \"%s\" dlsym(sk_api_version) failed: %s",
path, dlerror());
goto fail;
}
version = ret->sk_api_version();
debug("%s: provider %s implements version 0x%08lx", __func__,
ret->path, (u_long)version);
if ((version & SSH_SK_VERSION_MAJOR_MASK) != SSH_SK_VERSION_MAJOR) {
error("Provider \"%s\" implements unsupported "
"version 0x%08lx (supported: 0x%08lx)",
path, (u_long)version, (u_long)SSH_SK_VERSION_MAJOR);
goto fail;
}
if ((ret->sk_enroll = dlsym(ret->dlhandle, "sk_enroll")) == NULL) {
error("Provider %s dlsym(sk_enroll) failed: %s",
path, dlerror());
goto fail;
}
if ((ret->sk_sign = dlsym(ret->dlhandle, "sk_sign")) == NULL) {
error("Provider \"%s\" dlsym(sk_sign) failed: %s",
path, dlerror());
goto fail;
}
if ((ret->sk_load_resident_keys = dlsym(ret->dlhandle,
"sk_load_resident_keys")) == NULL) {
error("Provider \"%s\" dlsym(sk_load_resident_keys) "
"failed: %s", path, dlerror());
goto fail;
}
/* success */
return ret;
fail:
sshsk_free(ret);
return NULL;
}
static void
sshsk_free_enroll_response(struct sk_enroll_response *r)
{
if (r == NULL)
return;
freezero(r->key_handle, r->key_handle_len);
freezero(r->public_key, r->public_key_len);
freezero(r->signature, r->signature_len);
freezero(r->attestation_cert, r->attestation_cert_len);
freezero(r, sizeof(*r));
}
static void
sshsk_free_sign_response(struct sk_sign_response *r)
{
if (r == NULL)
return;
freezero(r->sig_r, r->sig_r_len);
freezero(r->sig_s, r->sig_s_len);
freezero(r, sizeof(*r));
}
#ifdef WITH_OPENSSL
/* Assemble key from response */
static int
sshsk_ecdsa_assemble(struct sk_enroll_response *resp, struct sshkey **keyp)
{
struct sshkey *key = NULL;
struct sshbuf *b = NULL;
EC_POINT *q = NULL;
int r;
*keyp = NULL;
if ((key = sshkey_new(KEY_ECDSA_SK)) == NULL) {
error("%s: sshkey_new failed", __func__);
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
key->ecdsa_nid = NID_X9_62_prime256v1;
if ((key->ecdsa = EC_KEY_new_by_curve_name(key->ecdsa_nid)) == NULL ||
(q = EC_POINT_new(EC_KEY_get0_group(key->ecdsa))) == NULL ||
(b = sshbuf_new()) == NULL) {
error("%s: allocation failed", __func__);
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_put_string(b,
resp->public_key, resp->public_key_len)) != 0) {
error("%s: buffer error: %s", __func__, ssh_err(r));
goto out;
}
if ((r = sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa))) != 0) {
error("%s: parse key: %s", __func__, ssh_err(r));
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if (sshkey_ec_validate_public(EC_KEY_get0_group(key->ecdsa), q) != 0) {
error("Authenticator returned invalid ECDSA key");
r = SSH_ERR_KEY_INVALID_EC_VALUE;
goto out;
}
if (EC_KEY_set_public_key(key->ecdsa, q) != 1) {
/* XXX assume it is a allocation error */
error("%s: allocation failed", __func__);
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
/* success */
*keyp = key;
key = NULL; /* transferred */
r = 0;
out:
EC_POINT_free(q);
sshkey_free(key);
sshbuf_free(b);
return r;
}
#endif /* WITH_OPENSSL */
static int
sshsk_ed25519_assemble(struct sk_enroll_response *resp, struct sshkey **keyp)
{
struct sshkey *key = NULL;
int r;
*keyp = NULL;
if (resp->public_key_len != ED25519_PK_SZ) {
error("%s: invalid size: %zu", __func__, resp->public_key_len);
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if ((key = sshkey_new(KEY_ED25519_SK)) == NULL) {
error("%s: sshkey_new failed", __func__);
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((key->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) {
error("%s: malloc failed", __func__);
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
memcpy(key->ed25519_pk, resp->public_key, ED25519_PK_SZ);
/* success */
*keyp = key;
key = NULL; /* transferred */
r = 0;
out:
sshkey_free(key);
return r;
}
static int
sshsk_key_from_response(int alg, const char *application, uint8_t flags,
struct sk_enroll_response *resp, struct sshkey **keyp)
{
struct sshkey *key = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
*keyp = NULL;
/* Check response validity */
if (resp->public_key == NULL || resp->key_handle == NULL) {
error("%s: sk_enroll response invalid", __func__);
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
switch (alg) {
#ifdef WITH_OPENSSL
case SSH_SK_ECDSA:
if ((r = sshsk_ecdsa_assemble(resp, &key)) != 0)
goto out;
break;
#endif /* WITH_OPENSSL */
case SSH_SK_ED25519:
if ((r = sshsk_ed25519_assemble(resp, &key)) != 0)
goto out;
break;
default:
error("%s: unsupported algorithm %d", __func__, alg);
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
key->sk_flags = flags;
if ((key->sk_key_handle = sshbuf_new()) == NULL ||
(key->sk_reserved = sshbuf_new()) == NULL) {
error("%s: allocation failed", __func__);
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((key->sk_application = strdup(application)) == NULL) {
error("%s: strdup application failed", __func__);
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_put(key->sk_key_handle, resp->key_handle,
resp->key_handle_len)) != 0) {
error("%s: buffer error: %s", __func__, ssh_err(r));
goto out;
}
/* success */
r = 0;
*keyp = key;
key = NULL;
out:
sshkey_free(key);
return r;
}
static int
skerr_to_ssherr(int skerr)
{
switch (skerr) {
case SSH_SK_ERR_UNSUPPORTED:
return SSH_ERR_FEATURE_UNSUPPORTED;
case SSH_SK_ERR_PIN_REQUIRED:
return SSH_ERR_KEY_WRONG_PASSPHRASE;
case SSH_SK_ERR_DEVICE_NOT_FOUND:
return SSH_ERR_DEVICE_NOT_FOUND;
case SSH_SK_ERR_GENERAL:
default:
return SSH_ERR_INVALID_FORMAT;
}
}
static void
sshsk_free_options(struct sk_option **opts)
{
size_t i;
if (opts == NULL)
return;
for (i = 0; opts[i] != NULL; i++) {
free(opts[i]->name);
free(opts[i]->value);
free(opts[i]);
}
free(opts);
}
static int
sshsk_add_option(struct sk_option ***optsp, size_t *noptsp,
const char *name, const char *value, uint8_t required)
{
struct sk_option **opts = *optsp;
size_t nopts = *noptsp;
if ((opts = recallocarray(opts, nopts, nopts + 2, /* extra for NULL */
sizeof(*opts))) == NULL) {
error("%s: array alloc failed", __func__);
return SSH_ERR_ALLOC_FAIL;
}
*optsp = opts;
*noptsp = nopts + 1;
if ((opts[nopts] = calloc(1, sizeof(**opts))) == NULL) {
error("%s: alloc failed", __func__);
return SSH_ERR_ALLOC_FAIL;
}
if ((opts[nopts]->name = strdup(name)) == NULL ||
(opts[nopts]->value = strdup(value)) == NULL) {
error("%s: alloc failed", __func__);
return SSH_ERR_ALLOC_FAIL;
}
opts[nopts]->required = required;
return 0;
}
static int
make_options(const char *device, const char *user_id,
struct sk_option ***optsp)
{
struct sk_option **opts = NULL;
size_t nopts = 0;
int r, ret = SSH_ERR_INTERNAL_ERROR;
if (device != NULL &&
(r = sshsk_add_option(&opts, &nopts, "device", device, 0)) != 0) {
ret = r;
goto out;
}
if (user_id != NULL &&
(r = sshsk_add_option(&opts, &nopts, "user", user_id, 0)) != 0) {
ret = r;
goto out;
}
/* success */
*optsp = opts;
opts = NULL;
nopts = 0;
ret = 0;
out:
sshsk_free_options(opts);
return ret;
}
int
sshsk_enroll(int type, const char *provider_path, const char *device,
const char *application, const char *userid, uint8_t flags,
const char *pin, struct sshbuf *challenge_buf,
struct sshkey **keyp, struct sshbuf *attest)
{
struct sshsk_provider *skp = NULL;
struct sshkey *key = NULL;
u_char randchall[32];
const u_char *challenge;
size_t challenge_len;
struct sk_enroll_response *resp = NULL;
struct sk_option **opts = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
int alg;
debug("%s: provider \"%s\", device \"%s\", application \"%s\", "
"userid \"%s\", flags 0x%02x, challenge len %zu%s", __func__,
provider_path, device, application, userid, flags,
challenge_buf == NULL ? 0 : sshbuf_len(challenge_buf),
(pin != NULL && *pin != '\0') ? " with-pin" : "");
*keyp = NULL;
if (attest)
sshbuf_reset(attest);
if ((r = make_options(device, userid, &opts)) != 0)
goto out;
switch (type) {
#ifdef WITH_OPENSSL
case KEY_ECDSA_SK:
alg = SSH_SK_ECDSA;
break;
#endif /* WITH_OPENSSL */
case KEY_ED25519_SK:
alg = SSH_SK_ED25519;
break;
default:
error("%s: unsupported key type", __func__);
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if (provider_path == NULL) {
error("%s: missing provider", __func__);
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if (application == NULL || *application == '\0') {
error("%s: missing application", __func__);
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if (challenge_buf == NULL) {
debug("%s: using random challenge", __func__);
arc4random_buf(randchall, sizeof(randchall));
challenge = randchall;
challenge_len = sizeof(randchall);
} else if (sshbuf_len(challenge_buf) == 0) {
error("Missing enrollment challenge");
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
} else {
challenge = sshbuf_ptr(challenge_buf);
challenge_len = sshbuf_len(challenge_buf);
debug3("%s: using explicit challenge len=%zd",
__func__, challenge_len);
}
if ((skp = sshsk_open(provider_path)) == NULL) {
r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */
goto out;
}
/* XXX validate flags? */
/* enroll key */
if ((r = skp->sk_enroll(alg, challenge, challenge_len, application,
flags, pin, opts, &resp)) != 0) {
debug("%s: provider \"%s\" returned failure %d", __func__,
provider_path, r);
r = skerr_to_ssherr(r);
goto out;
}
if ((r = sshsk_key_from_response(alg, application, flags,
resp, &key)) != 0)
goto out;
/* Optionally fill in the attestation information */
if (attest != NULL) {
if ((r = sshbuf_put_cstring(attest,
"ssh-sk-attest-v00")) != 0 ||
(r = sshbuf_put_string(attest,
resp->attestation_cert, resp->attestation_cert_len)) != 0 ||
(r = sshbuf_put_string(attest,
resp->signature, resp->signature_len)) != 0 ||
(r = sshbuf_put_u32(attest, 0)) != 0 || /* resvd flags */
(r = sshbuf_put_string(attest, NULL, 0)) != 0 /* resvd */) {
error("%s: buffer error: %s", __func__, ssh_err(r));
goto out;
}
}
/* success */
*keyp = key;
key = NULL; /* transferred */
r = 0;
out:
sshsk_free_options(opts);
sshsk_free(skp);
sshkey_free(key);
sshsk_free_enroll_response(resp);
explicit_bzero(randchall, sizeof(randchall));
return r;
}
#ifdef WITH_OPENSSL
static int
sshsk_ecdsa_sig(struct sk_sign_response *resp, struct sshbuf *sig)
{
struct sshbuf *inner_sig = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
/* Check response validity */
if (resp->sig_r == NULL || resp->sig_s == NULL) {
error("%s: sk_sign response invalid", __func__);
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if ((inner_sig = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
/* Prepare and append inner signature object */
if ((r = sshbuf_put_bignum2_bytes(inner_sig,
resp->sig_r, resp->sig_r_len)) != 0 ||
(r = sshbuf_put_bignum2_bytes(inner_sig,
resp->sig_s, resp->sig_s_len)) != 0) {
debug("%s: buffer error: %s", __func__, ssh_err(r));
goto out;
}
if ((r = sshbuf_put_stringb(sig, inner_sig)) != 0 ||
(r = sshbuf_put_u8(sig, resp->flags)) != 0 ||
(r = sshbuf_put_u32(sig, resp->counter)) != 0) {
debug("%s: buffer error: %s", __func__, ssh_err(r));
goto out;
}
#ifdef DEBUG_SK
fprintf(stderr, "%s: sig_r:\n", __func__);
sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr);
fprintf(stderr, "%s: sig_s:\n", __func__);
sshbuf_dump_data(resp->sig_s, resp->sig_s_len, stderr);
fprintf(stderr, "%s: inner:\n", __func__);
sshbuf_dump(inner_sig, stderr);
#endif
r = 0;
out:
sshbuf_free(inner_sig);
return r;
}
#endif /* WITH_OPENSSL */
static int
sshsk_ed25519_sig(struct sk_sign_response *resp, struct sshbuf *sig)
{
int r = SSH_ERR_INTERNAL_ERROR;
/* Check response validity */
if (resp->sig_r == NULL) {
error("%s: sk_sign response invalid", __func__);
r = SSH_ERR_INVALID_FORMAT;
goto out;
}
if ((r = sshbuf_put_string(sig,
resp->sig_r, resp->sig_r_len)) != 0 ||
(r = sshbuf_put_u8(sig, resp->flags)) != 0 ||
(r = sshbuf_put_u32(sig, resp->counter)) != 0) {
debug("%s: buffer error: %s", __func__, ssh_err(r));
goto out;
}
#ifdef DEBUG_SK
fprintf(stderr, "%s: sig_r:\n", __func__);
sshbuf_dump_data(resp->sig_r, resp->sig_r_len, stderr);
#endif
r = 0;
out:
return r;
}
int
sshsk_sign(const char *provider_path, struct sshkey *key,
u_char **sigp, size_t *lenp, const u_char *data, size_t datalen,
u_int compat, const char *pin)
{
struct sshsk_provider *skp = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
int type, alg;
struct sk_sign_response *resp = NULL;
struct sshbuf *inner_sig = NULL, *sig = NULL;
uint8_t message[32];
struct sk_option **opts = NULL;
debug("%s: provider \"%s\", key %s, flags 0x%02x%s", __func__,
provider_path, sshkey_type(key), key->sk_flags,
(pin != NULL && *pin != '\0') ? " with-pin" : "");
if (sigp != NULL)
*sigp = NULL;
if (lenp != NULL)
*lenp = 0;
type = sshkey_type_plain(key->type);
switch (type) {
#ifdef WITH_OPENSSL
case KEY_ECDSA_SK:
alg = SSH_SK_ECDSA;
break;
#endif /* WITH_OPENSSL */
case KEY_ED25519_SK:
alg = SSH_SK_ED25519;
break;
default:
return SSH_ERR_INVALID_ARGUMENT;
}
if (provider_path == NULL ||
key->sk_key_handle == NULL ||
key->sk_application == NULL || *key->sk_application == '\0') {
r = SSH_ERR_INVALID_ARGUMENT;
goto out;
}
if ((skp = sshsk_open(provider_path)) == NULL) {
r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */
goto out;
}
/* hash data to be signed before it goes to the security key */
if ((r = ssh_digest_memory(SSH_DIGEST_SHA256, data, datalen,
message, sizeof(message))) != 0) {
error("%s: hash application failed: %s", __func__, ssh_err(r));
r = SSH_ERR_INTERNAL_ERROR;
goto out;
}
if ((r = skp->sk_sign(alg, message, sizeof(message),
key->sk_application,
sshbuf_ptr(key->sk_key_handle), sshbuf_len(key->sk_key_handle),
key->sk_flags, pin, opts, &resp)) != 0) {
debug("%s: sk_sign failed with code %d", __func__, r);
r = skerr_to_ssherr(r);
goto out;
}
/* Assemble signature */
if ((sig = sshbuf_new()) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
if ((r = sshbuf_put_cstring(sig, sshkey_ssh_name_plain(key))) != 0) {
debug("%s: buffer error (outer): %s", __func__, ssh_err(r));
goto out;
}
switch (type) {
#ifdef WITH_OPENSSL
case KEY_ECDSA_SK:
if ((r = sshsk_ecdsa_sig(resp, sig)) != 0)
goto out;
break;
#endif /* WITH_OPENSSL */
case KEY_ED25519_SK:
if ((r = sshsk_ed25519_sig(resp, sig)) != 0)
goto out;
break;
}
#ifdef DEBUG_SK
fprintf(stderr, "%s: sig_flags = 0x%02x, sig_counter = %u\n",
__func__, resp->flags, resp->counter);
fprintf(stderr, "%s: hashed message:\n", __func__);
sshbuf_dump_data(message, sizeof(message), stderr);
fprintf(stderr, "%s: sigbuf:\n", __func__);
sshbuf_dump(sig, stderr);
#endif
if (sigp != NULL) {
if ((*sigp = malloc(sshbuf_len(sig))) == NULL) {
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
memcpy(*sigp, sshbuf_ptr(sig), sshbuf_len(sig));
}
if (lenp != NULL)
*lenp = sshbuf_len(sig);
/* success */
r = 0;
out:
sshsk_free_options(opts);
explicit_bzero(message, sizeof(message));
sshsk_free(skp);
sshsk_free_sign_response(resp);
sshbuf_free(sig);
sshbuf_free(inner_sig);
return r;
}
static void
sshsk_free_sk_resident_keys(struct sk_resident_key **rks, size_t nrks)
{
size_t i;
if (nrks == 0 || rks == NULL)
return;
for (i = 0; i < nrks; i++) {
free(rks[i]->application);
freezero(rks[i]->key.key_handle, rks[i]->key.key_handle_len);
freezero(rks[i]->key.public_key, rks[i]->key.public_key_len);
freezero(rks[i]->key.signature, rks[i]->key.signature_len);
freezero(rks[i]->key.attestation_cert,
rks[i]->key.attestation_cert_len);
freezero(rks[i], sizeof(**rks));
}
free(rks);
}
int
sshsk_load_resident(const char *provider_path, const char *device,
const char *pin, struct sshkey ***keysp, size_t *nkeysp)
{
struct sshsk_provider *skp = NULL;
int r = SSH_ERR_INTERNAL_ERROR;
struct sk_resident_key **rks = NULL;
size_t i, nrks = 0, nkeys = 0;
struct sshkey *key = NULL, **keys = NULL, **tmp;
uint8_t flags;
struct sk_option **opts = NULL;
debug("%s: provider \"%s\"%s", __func__, provider_path,
(pin != NULL && *pin != '\0') ? ", have-pin": "");
if (keysp == NULL || nkeysp == NULL)
return SSH_ERR_INVALID_ARGUMENT;
*keysp = NULL;
*nkeysp = 0;
if ((r = make_options(device, NULL, &opts)) != 0)
goto out;
if ((skp = sshsk_open(provider_path)) == NULL) {
r = SSH_ERR_INVALID_FORMAT; /* XXX sshsk_open return code? */
goto out;
}
if ((r = skp->sk_load_resident_keys(pin, opts, &rks, &nrks)) != 0) {
error("Provider \"%s\" returned failure %d", provider_path, r);
r = skerr_to_ssherr(r);
goto out;
}
for (i = 0; i < nrks; i++) {
debug3("%s: rk %zu: slot = %zu, alg = %d, application = \"%s\"",
__func__, i, rks[i]->slot, rks[i]->alg,
rks[i]->application);
/* XXX need better filter here */
if (strncmp(rks[i]->application, "ssh:", 4) != 0)
continue;
switch (rks[i]->alg) {
case SSH_SK_ECDSA:
case SSH_SK_ED25519:
break;
default:
continue;
}
/* XXX where to get flags? */
flags = SSH_SK_USER_PRESENCE_REQD|SSH_SK_RESIDENT_KEY;
if ((r = sshsk_key_from_response(rks[i]->alg,
rks[i]->application, flags, &rks[i]->key, &key)) != 0)
goto out;
if ((tmp = recallocarray(keys, nkeys, nkeys + 1,
sizeof(*tmp))) == NULL) {
error("%s: recallocarray failed", __func__);
r = SSH_ERR_ALLOC_FAIL;
goto out;
}
keys = tmp;
keys[nkeys++] = key;
key = NULL;
/* XXX synthesise comment */
}
/* success */
*keysp = keys;
*nkeysp = nkeys;
keys = NULL;
nkeys = 0;
r = 0;
out:
sshsk_free_options(opts);
sshsk_free(skp);
sshsk_free_sk_resident_keys(rks, nrks);
sshkey_free(key);
if (nkeys != 0) {
for (i = 0; i < nkeys; i++)
sshkey_free(keys[i]);
free(keys);
}
return r;
}
#endif /* ENABLE_SK */
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