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-rw-r--r--ssh-sk.c879
1 files changed, 879 insertions, 0 deletions
diff --git a/ssh-sk.c b/ssh-sk.c
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+++ b/ssh-sk.c
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+/* $OpenBSD: ssh-sk.c,v 1.40 2023/07/19 14:02:27 djm 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>
+
+#if defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC)
+#include <openssl/objects.h>
+#include <openssl/ec.h>
+#endif /* WITH_OPENSSL && OPENSSL_HAS_ECC */
+
+#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"
+
+/*
+ * Almost every use of OpenSSL in this file is for ECDSA-NISTP256.
+ * This is strictly a larger hammer than necessary, but it reduces changes
+ * with upstream.
+ */
+#ifndef OPENSSL_HAS_ECC
+# undef WITH_OPENSSL
+#endif
+
+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_f("calloc failed");
+ return NULL;
+ }
+ if ((ret->path = strdup(path)) == NULL) {
+ error_f("strdup failed");
+ 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;
+ return ret;
+#else
+ error("internal security key support not enabled");
+ goto fail;
+#endif
+ }
+ if (lib_contains_symbol(path, "sk_api_version") != 0) {
+ error("provider %s is not an OpenSSH FIDO library", path);
+ goto fail;
+ }
+ if ((ret->dlhandle = dlopen(path, RTLD_NOW)) == NULL)
+ fatal("Provider \"%s\" dlopen failed: %s", path, dlerror());
+ 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_f("provider %s implements version 0x%08lx", 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->authdata, r->authdata_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_f("sshkey_new failed");
+ 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_f("allocation failed");
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ if ((r = sshbuf_put_string(b,
+ resp->public_key, resp->public_key_len)) != 0) {
+ error_fr(r, "sshbuf_put_string");
+ goto out;
+ }
+ if ((r = sshbuf_get_ec(b, q, EC_KEY_get0_group(key->ecdsa))) != 0) {
+ error_fr(r, "parse");
+ 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_f("allocation failed");
+ 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_f("invalid size: %zu", resp->public_key_len);
+ r = SSH_ERR_INVALID_FORMAT;
+ goto out;
+ }
+ if ((key = sshkey_new(KEY_ED25519_SK)) == NULL) {
+ error_f("sshkey_new failed");
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ if ((key->ed25519_pk = malloc(ED25519_PK_SZ)) == NULL) {
+ error_f("malloc failed");
+ 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_f("sk_enroll response invalid");
+ 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_f("unsupported algorithm %d", 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_f("allocation failed");
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ if ((key->sk_application = strdup(application)) == NULL) {
+ error_f("strdup application failed");
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ if ((r = sshbuf_put(key->sk_key_handle, resp->key_handle,
+ resp->key_handle_len)) != 0) {
+ error_fr(r, "put key handle");
+ 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_CREDENTIAL_EXISTS:
+ return SSH_ERR_KEY_BAD_PERMISSIONS;
+ 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_f("array alloc failed");
+ return SSH_ERR_ALLOC_FAIL;
+ }
+ *optsp = opts;
+ *noptsp = nopts + 1;
+ if ((opts[nopts] = calloc(1, sizeof(**opts))) == NULL) {
+ error_f("alloc failed");
+ return SSH_ERR_ALLOC_FAIL;
+ }
+ if ((opts[nopts]->name = strdup(name)) == NULL ||
+ (opts[nopts]->value = strdup(value)) == NULL) {
+ error_f("alloc failed");
+ 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;
+}
+
+
+static int
+fill_attestation_blob(const struct sk_enroll_response *resp,
+ struct sshbuf *attest)
+{
+ int r;
+
+ if (attest == NULL)
+ return 0; /* nothing to do */
+ if ((r = sshbuf_put_cstring(attest, "ssh-sk-attest-v01")) != 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_string(attest,
+ resp->authdata, resp->authdata_len)) != 0 ||
+ (r = sshbuf_put_u32(attest, 0)) != 0 || /* resvd flags */
+ (r = sshbuf_put_string(attest, NULL, 0)) != 0 /* resvd */) {
+ error_fr(r, "compose");
+ return r;
+ }
+ /* success */
+ return 0;
+}
+
+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_f("provider \"%s\", device \"%s\", application \"%s\", "
+ "userid \"%s\", flags 0x%02x, challenge len %zu%s",
+ 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_f("unsupported key type");
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto out;
+ }
+ if (provider_path == NULL) {
+ error_f("missing provider");
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto out;
+ }
+ if (application == NULL || *application == '\0') {
+ error_f("missing application");
+ r = SSH_ERR_INVALID_ARGUMENT;
+ goto out;
+ }
+ if (challenge_buf == NULL) {
+ debug_f("using random challenge");
+ 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_f("using explicit challenge len=%zd", 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_f("provider \"%s\" failure %d", provider_path, r);
+ r = skerr_to_ssherr(r);
+ goto out;
+ }
+
+ if ((r = sshsk_key_from_response(alg, application, resp->flags,
+ resp, &key)) != 0)
+ goto out;
+
+ /* Optionally fill in the attestation information */
+ if ((r = fill_attestation_blob(resp, attest)) != 0)
+ 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_f("sk_sign response invalid");
+ 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) {
+ error_fr(r, "compose inner");
+ 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) {
+ error_fr(r, "compose");
+ 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_f("sk_sign response invalid");
+ 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) {
+ error_fr(r, "compose");
+ 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;
+ struct sk_option **opts = NULL;
+
+ debug_f("provider \"%s\", key %s, flags 0x%02x%s",
+ 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;
+ }
+#ifdef DEBUG_SK
+ fprintf(stderr, "%s: sk_flags = 0x%02x, sk_application = \"%s\"\n",
+ __func__, key->sk_flags, key->sk_application);
+ fprintf(stderr, "%s: sk_key_handle:\n", __func__);
+ sshbuf_dump(key->sk_key_handle, stderr);
+#endif
+ if ((r = skp->sk_sign(alg, data, datalen, key->sk_application,
+ sshbuf_ptr(key->sk_key_handle), sshbuf_len(key->sk_key_handle),
+ key->sk_flags, pin, opts, &resp)) != 0) {
+ debug_f("sk_sign failed with code %d", 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) {
+ error_fr(r, "compose outer");
+ 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: data to sign:\n", __func__);
+ sshbuf_dump_data(data, datalen, 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);
+ 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]->user_id, rks[i]->user_id_len);
+ 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);
+}
+
+static void
+sshsk_free_resident_key(struct sshsk_resident_key *srk)
+{
+ if (srk == NULL)
+ return;
+ sshkey_free(srk->key);
+ freezero(srk->user_id, srk->user_id_len);
+ free(srk);
+}
+
+
+void
+sshsk_free_resident_keys(struct sshsk_resident_key **srks, size_t nsrks)
+{
+ size_t i;
+
+ if (srks == NULL || nsrks == 0)
+ return;
+
+ for (i = 0; i < nsrks; i++)
+ sshsk_free_resident_key(srks[i]);
+ free(srks);
+}
+
+int
+sshsk_load_resident(const char *provider_path, const char *device,
+ const char *pin, u_int flags, struct sshsk_resident_key ***srksp,
+ size_t *nsrksp)
+{
+ struct sshsk_provider *skp = NULL;
+ int r = SSH_ERR_INTERNAL_ERROR;
+ struct sk_resident_key **rks = NULL;
+ size_t i, nrks = 0, nsrks = 0;
+ struct sshkey *key = NULL;
+ struct sshsk_resident_key *srk = NULL, **srks = NULL, **tmp;
+ uint8_t sk_flags;
+ struct sk_option **opts = NULL;
+
+ debug_f("provider \"%s\"%s", provider_path,
+ (pin != NULL && *pin != '\0') ? ", have-pin": "");
+
+ if (srksp == NULL || nsrksp == NULL)
+ return SSH_ERR_INVALID_ARGUMENT;
+ *srksp = NULL;
+ *nsrksp = 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_f("rk %zu: slot %zu, alg %d, app \"%s\", uidlen %zu",
+ i, rks[i]->slot, rks[i]->alg, rks[i]->application,
+ rks[i]->user_id_len);
+ /* 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;
+ }
+ sk_flags = SSH_SK_USER_PRESENCE_REQD|SSH_SK_RESIDENT_KEY;
+ if ((rks[i]->flags & SSH_SK_USER_VERIFICATION_REQD))
+ sk_flags |= SSH_SK_USER_VERIFICATION_REQD;
+ if ((r = sshsk_key_from_response(rks[i]->alg,
+ rks[i]->application, sk_flags, &rks[i]->key, &key)) != 0)
+ goto out;
+ if ((srk = calloc(1, sizeof(*srk))) == NULL) {
+ error_f("calloc failed");
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ srk->key = key;
+ key = NULL; /* transferred */
+ if ((srk->user_id = calloc(1, rks[i]->user_id_len)) == NULL) {
+ error_f("calloc failed");
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ memcpy(srk->user_id, rks[i]->user_id, rks[i]->user_id_len);
+ srk->user_id_len = rks[i]->user_id_len;
+ if ((tmp = recallocarray(srks, nsrks, nsrks + 1,
+ sizeof(*tmp))) == NULL) {
+ error_f("recallocarray failed");
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ srks = tmp;
+ srks[nsrks++] = srk;
+ srk = NULL;
+ /* XXX synthesise comment */
+ }
+ /* success */
+ *srksp = srks;
+ *nsrksp = nsrks;
+ srks = NULL;
+ nsrks = 0;
+ r = 0;
+ out:
+ sshsk_free_options(opts);
+ sshsk_free(skp);
+ sshsk_free_sk_resident_keys(rks, nrks);
+ sshkey_free(key);
+ sshsk_free_resident_key(srk);
+ sshsk_free_resident_keys(srks, nsrks);
+ return r;
+}
+
+#endif /* ENABLE_SK */