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gerrit.cesnet.cz / github / CESNET / libnetconf2 / 63b92d6a8dd055b6e52dede5abdf1e4e550c2cbe / . / src / session_server_tls.c
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/**
* @file session_server_tls.c
* @author Michal Vasko <mvasko@cesnet.cz>
* @author Roman Janota <janota@cesnet.cz>
* @brief libnetconf2 TLS server session manipulation functions
*
* @copyright
* Copyright (c) 2015 - 2023 CESNET, z.s.p.o.
*
* This source code is licensed under BSD 3-Clause License (the "License").
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://opensource.org/licenses/BSD-3-Clause
*/
#define _GNU_SOURCE
#include <poll.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <curl/curl.h>
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/ssl.h>
#include <openssl/x509.h>
#include <openssl/x509v3.h>
#include "compat.h"
#include "config.h"
#include "log_p.h"
#include "session.h"
#include "session_p.h"
struct nc_server_tls_opts tls_ch_opts;
extern struct nc_server_opts server_opts;
static char *
asn1time_to_str(const ASN1_TIME *t)
{
char *cp;
BIO *bio;
int n;
if (!t) {
return NULL;
}
bio = BIO_new(BIO_s_mem());
if (!bio) {
return NULL;
}
ASN1_TIME_print(bio, t);
n = BIO_pending(bio);
cp = malloc(n + 1);
if (!cp) {
ERRMEM;
BIO_free(bio);
return NULL;
}
n = BIO_read(bio, cp, n);
if (n < 0) {
BIO_free(bio);
free(cp);
return NULL;
}
cp[n] = '\0';
BIO_free(bio);
return cp;
}
static void
digest_to_str(const unsigned char *digest, unsigned int dig_len, char **str)
{
unsigned int i;
*str = malloc(dig_len * 3);
if (!*str) {
ERRMEM;
return;
}
for (i = 0; i < dig_len - 1; ++i) {
sprintf((*str) + (i * 3), "%02x:", digest[i]);
}
sprintf((*str) + (i * 3), "%02x", digest[i]);
}
/* return NULL - SSL error can be retrieved */
static X509 *
base64der_to_cert(const char *in)
{
X509 *out;
char *buf;
BIO *bio;
if (in == NULL) {
return NULL;
}
if (asprintf(&buf, "%s%s%s", "-----BEGIN CERTIFICATE-----\n", in, "\n-----END CERTIFICATE-----") == -1) {
return NULL;
}
bio = BIO_new_mem_buf(buf, strlen(buf));
if (!bio) {
free(buf);
return NULL;
}
out = PEM_read_bio_X509(bio, NULL, NULL, NULL);
if (!out) {
free(buf);
BIO_free(bio);
return NULL;
}
free(buf);
BIO_free(bio);
return out;
}
static EVP_PKEY *
base64der_to_privatekey(const char *in, const char *key_str)
{
EVP_PKEY *out;
char *buf;
BIO *bio;
if (in == NULL) {
return NULL;
}
if (!key_str) {
/* avoid writing (null) for possibly unknown key formats */
key_str = "";
}
if (asprintf(&buf, "%s%s%s%s%s%s%s", "-----BEGIN", key_str, "PRIVATE KEY-----\n", in, "\n-----END",
key_str, "PRIVATE KEY-----") == -1) {
return NULL;
}
bio = BIO_new_mem_buf(buf, strlen(buf));
if (!bio) {
free(buf);
return NULL;
}
out = PEM_read_bio_PrivateKey(bio, NULL, NULL, NULL);
if (!out) {
free(buf);
BIO_free(bio);
return NULL;
}
free(buf);
BIO_free(bio);
return out;
}
static int
cert_pubkey_match(X509 *cert1, X509 *cert2)
{
ASN1_BIT_STRING *bitstr1, *bitstr2;
bitstr1 = X509_get0_pubkey_bitstr(cert1);
bitstr2 = X509_get0_pubkey_bitstr(cert2);
if (!bitstr1 || !bitstr2 || (bitstr1->length != bitstr2->length) ||
memcmp(bitstr1->data, bitstr2->data, bitstr1->length)) {
return 0;
}
return 1;
}
static int
nc_tls_ctn_get_username_from_cert(X509 *client_cert, NC_TLS_CTN_MAPTYPE map_type, char **username)
{
STACK_OF(GENERAL_NAME) * san_names;
GENERAL_NAME *san_name;
ASN1_OCTET_STRING *ip;
int i, san_count;
char *subject, *common_name;
*username = NULL;
if (map_type == NC_TLS_CTN_COMMON_NAME) {
subject = X509_NAME_oneline(X509_get_subject_name(client_cert), NULL, 0);
common_name = strstr(subject, "CN=");
if (!common_name) {
WRN(NULL, "Certificate does not include the commonName field.");
free(subject);
return 1;
}
common_name += 3;
if (strchr(common_name, '/')) {
*strchr(common_name, '/') = '\0';
}
*username = strdup(common_name);
NC_CHECK_ERRMEM_RET(!*username, 1);
free(subject);
} else {
/* retrieve subjectAltName's rfc822Name (email), dNSName and iPAddress values */
san_names = X509_get_ext_d2i(client_cert, NID_subject_alt_name, NULL, NULL);
if (!san_names) {
WRN(NULL, "Certificate has no SANs or failed to retrieve them.");
return 1;
}
san_count = sk_GENERAL_NAME_num(san_names);
for (i = 0; i < san_count; ++i) {
san_name = sk_GENERAL_NAME_value(san_names, i);
/* rfc822Name (email) */
if (((map_type == NC_TLS_CTN_SAN_ANY) || (map_type == NC_TLS_CTN_SAN_RFC822_NAME)) &&
(san_name->type == GEN_EMAIL)) {
*username = strdup((char *)ASN1_STRING_get0_data(san_name->d.rfc822Name));
NC_CHECK_ERRMEM_RET(!*username, 1);
break;
}
/* dNSName */
if (((map_type == NC_TLS_CTN_SAN_ANY) || (map_type == NC_TLS_CTN_SAN_DNS_NAME)) &&
(san_name->type == GEN_DNS)) {
*username = strdup((char *)ASN1_STRING_get0_data(san_name->d.dNSName));
NC_CHECK_ERRMEM_RET(!*username, 1);
break;
}
/* iPAddress */
if (((map_type == NC_TLS_CTN_SAN_ANY) || (map_type == NC_TLS_CTN_SAN_IP_ADDRESS)) &&
(san_name->type == GEN_IPADD)) {
ip = san_name->d.iPAddress;
if (ip->length == 4) {
if (asprintf(username, "%d.%d.%d.%d", ip->data[0], ip->data[1], ip->data[2], ip->data[3]) == -1) {
ERRMEM;
sk_GENERAL_NAME_pop_free(san_names, GENERAL_NAME_free);
return -1;
}
break;
} else if (ip->length == 16) {
if (asprintf(username, "%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
ip->data[0], ip->data[1], ip->data[2], ip->data[3], ip->data[4], ip->data[5],
ip->data[6], ip->data[7], ip->data[8], ip->data[9], ip->data[10], ip->data[11],
ip->data[12], ip->data[13], ip->data[14], ip->data[15]) == -1) {
ERRMEM;
sk_GENERAL_NAME_pop_free(san_names, GENERAL_NAME_free);
return -1;
}
break;
} else {
WRN(NULL, "SAN IP address in an unknown format (length is %d).", ip->length);
}
}
}
sk_GENERAL_NAME_pop_free(san_names, GENERAL_NAME_free);
if (i == san_count) {
switch (map_type) {
case NC_TLS_CTN_SAN_RFC822_NAME:
WRN(NULL, "Certificate does not include the SAN rfc822Name field.");
break;
case NC_TLS_CTN_SAN_DNS_NAME:
WRN(NULL, "Certificate does not include the SAN dNSName field.");
break;
case NC_TLS_CTN_SAN_IP_ADDRESS:
WRN(NULL, "Certificate does not include the SAN iPAddress field.");
break;
case NC_TLS_CTN_SAN_ANY:
WRN(NULL, "Certificate does not include any relevant SAN fields.");
break;
default:
break;
}
return 1;
}
}
return 0;
}
/* return: 0 - OK, 1 - no match, -1 - error */
static int
nc_tls_cert_to_name(struct nc_session *session, struct nc_ctn *ctn_first, X509 *cert)
{
char *digest_md5 = NULL, *digest_sha1 = NULL, *digest_sha224 = NULL;
char *digest_sha256 = NULL, *digest_sha384 = NULL, *digest_sha512 = NULL;
unsigned char *buf;
unsigned int buf_len = 64;
int ret = 0;
struct nc_ctn *ctn;
NC_TLS_CTN_MAPTYPE map_type;
char *username = NULL;
buf = malloc(buf_len);
NC_CHECK_ERRMEM_RET(!buf, -1);
if (!session || !cert) {
free(buf);
return -1;
}
for (ctn = ctn_first; ctn; ctn = ctn->next) {
/* reset map_type */
map_type = NC_TLS_CTN_UNKNOWN;
/* first make sure the entry is valid */
if (!ctn->map_type || ((ctn->map_type == NC_TLS_CTN_SPECIFIED) && !ctn->name)) {
VRB(session, "Cert verify CTN: entry with id %u not valid, skipping.", ctn->id);
continue;
}
/* if ctn has no fingerprint, it will match any certificate */
if (!ctn->fingerprint) {
map_type = ctn->map_type;
/* MD5 */
} else if (!strncmp(ctn->fingerprint, "01", 2)) {
if (!digest_md5) {
if (X509_digest(cert, EVP_md5(), buf, &buf_len) != 1) {
ERR(session, "Calculating MD5 digest failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
digest_to_str(buf, buf_len, &digest_md5);
}
if (!strcasecmp(ctn->fingerprint + 3, digest_md5)) {
/* we got ourselves a potential winner! */
VRB(session, "Cert verify CTN: entry with a matching fingerprint found.");
map_type = ctn->map_type;
}
free(digest_md5);
digest_md5 = NULL;
/* SHA-1 */
} else if (!strncmp(ctn->fingerprint, "02", 2)) {
if (!digest_sha1) {
if (X509_digest(cert, EVP_sha1(), buf, &buf_len) != 1) {
ERR(session, "Calculating SHA-1 digest failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
digest_to_str(buf, buf_len, &digest_sha1);
}
if (!strcasecmp(ctn->fingerprint + 3, digest_sha1)) {
/* we got ourselves a potential winner! */
VRB(session, "Cert verify CTN: entry with a matching fingerprint found.");
map_type = ctn->map_type;
}
free(digest_sha1);
digest_sha1 = NULL;
/* SHA-224 */
} else if (!strncmp(ctn->fingerprint, "03", 2)) {
if (!digest_sha224) {
if (X509_digest(cert, EVP_sha224(), buf, &buf_len) != 1) {
ERR(session, "Calculating SHA-224 digest failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
digest_to_str(buf, buf_len, &digest_sha224);
}
if (!strcasecmp(ctn->fingerprint + 3, digest_sha224)) {
/* we got ourselves a potential winner! */
VRB(session, "Cert verify CTN: entry with a matching fingerprint found.");
map_type = ctn->map_type;
}
free(digest_sha224);
digest_sha224 = NULL;
/* SHA-256 */
} else if (!strncmp(ctn->fingerprint, "04", 2)) {
if (!digest_sha256) {
if (X509_digest(cert, EVP_sha256(), buf, &buf_len) != 1) {
ERR(session, "Calculating SHA-256 digest failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
digest_to_str(buf, buf_len, &digest_sha256);
}
if (!strcasecmp(ctn->fingerprint + 3, digest_sha256)) {
/* we got ourselves a potential winner! */
VRB(session, "Cert verify CTN: entry with a matching fingerprint found.");
map_type = ctn->map_type;
}
free(digest_sha256);
digest_sha256 = NULL;
/* SHA-384 */
} else if (!strncmp(ctn->fingerprint, "05", 2)) {
if (!digest_sha384) {
if (X509_digest(cert, EVP_sha384(), buf, &buf_len) != 1) {
ERR(session, "Calculating SHA-384 digest failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
digest_to_str(buf, buf_len, &digest_sha384);
}
if (!strcasecmp(ctn->fingerprint + 3, digest_sha384)) {
/* we got ourselves a potential winner! */
VRB(session, "Cert verify CTN: entry with a matching fingerprint found.");
map_type = ctn->map_type;
}
free(digest_sha384);
digest_sha384 = NULL;
/* SHA-512 */
} else if (!strncmp(ctn->fingerprint, "06", 2)) {
if (!digest_sha512) {
if (X509_digest(cert, EVP_sha512(), buf, &buf_len) != 1) {
ERR(session, "Calculating SHA-512 digest failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
digest_to_str(buf, buf_len, &digest_sha512);
}
if (!strcasecmp(ctn->fingerprint + 3, digest_sha512)) {
/* we got ourselves a potential winner! */
VRB(session, "Cert verify CTN: entry with a matching fingerprint found.");
map_type = ctn->map_type;
}
free(digest_sha512);
digest_sha512 = NULL;
/* unknown */
} else {
WRN(session, "Unknown fingerprint algorithm used (%s), skipping.", ctn->fingerprint);
continue;
}
if (map_type != NC_TLS_CTN_UNKNOWN) {
/* found a fingerprint match */
if (map_type == NC_TLS_CTN_SPECIFIED) {
/* specified -> get username from the ctn entry */
session->username = strdup(ctn->name);
NC_CHECK_ERRMEM_GOTO(!session->username, ret = -1, cleanup);
} else {
/* try to get the username from the cert with this ctn's map type */
ret = nc_tls_ctn_get_username_from_cert(session->opts.server.client_cert, map_type, &username);
if (ret == -1) {
/* fatal error */
goto cleanup;
} else if (ret) {
/* didn't get username, try next ctn entry */
continue;
}
/* success */
session->username = username;
}
/* matching fingerprint found and username obtained, success */
ret = 0;
goto cleanup;
}
}
if (!ctn) {
ret = 1;
}
cleanup:
free(digest_md5);
free(digest_sha1);
free(digest_sha224);
free(digest_sha256);
free(digest_sha384);
free(digest_sha512);
free(buf);
return ret;
}
static int
nc_server_tls_check_crl(X509_STORE *crl_store, X509_STORE_CTX *x509_ctx, X509 *cert,
const X509_NAME *subject, const X509_NAME *issuer)
{
int n, i, ret = 0;
X509_STORE_CTX *store_ctx = NULL;
X509_OBJECT *obj = NULL;
X509_CRL *crl;
X509_REVOKED *revoked;
EVP_PKEY *pubkey;
const ASN1_INTEGER *serial;
const ASN1_TIME *last_update = NULL, *next_update = NULL;
char *cp;
store_ctx = X509_STORE_CTX_new();
NC_CHECK_ERRMEM_GOTO(!store_ctx, ret = -1, cleanup);
/* init store context */
ret = X509_STORE_CTX_init(store_ctx, crl_store, NULL, NULL);
if (!ret) {
ERR(NULL, "Initializing x509 store ctx failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
ret = 0;
/* try to find a CRL entry that corresponds to the current certificate in question */
obj = X509_STORE_CTX_get_obj_by_subject(store_ctx, X509_LU_CRL, subject);
crl = X509_OBJECT_get0_X509_CRL(obj);
X509_OBJECT_free(obj);
if (crl) {
/* found it */
cp = X509_NAME_oneline(subject, NULL, 0);
VRB(NULL, "Cert verify CRL: issuer: %s.", cp);
OPENSSL_free(cp);
last_update = X509_CRL_get0_lastUpdate(crl);
next_update = X509_CRL_get0_nextUpdate(crl);
cp = asn1time_to_str(last_update);
VRB(NULL, "Cert verify CRL: last update: %s.", cp);
free(cp);
cp = asn1time_to_str(next_update);
VRB(NULL, "Cert verify CRL: next update: %s.", cp);
free(cp);
/* verify the signature on this CRL */
pubkey = X509_get0_pubkey(cert);
if (X509_CRL_verify(crl, pubkey) <= 0) {
ERR(NULL, "Cert verify CRL: invalid signature.");
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CRL_SIGNATURE_FAILURE);
ret = -1;
goto cleanup;
}
/* check date of CRL to make sure it's not expired */
if (!next_update) {
ERR(NULL, "Cert verify CRL: invalid nextUpdate field.");
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD);
ret = -1;
goto cleanup;
}
if (X509_cmp_current_time(next_update) < 0) {
ERR(NULL, "Cert verify CRL: expired - revoking all certificates.");
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CRL_HAS_EXPIRED);
ret = -1;
goto cleanup;
}
}
/* try to retrieve a CRL corresponding to the _issuer_ of
* the current certificate in order to check for revocation */
obj = X509_STORE_CTX_get_obj_by_subject(store_ctx, X509_LU_CRL, issuer);
crl = X509_OBJECT_get0_X509_CRL(obj);
if (crl) {
n = sk_X509_REVOKED_num(X509_CRL_get_REVOKED(crl));
for (i = 0; i < n; i++) {
revoked = sk_X509_REVOKED_value(X509_CRL_get_REVOKED(crl), i);
serial = X509_REVOKED_get0_serialNumber(revoked);
if (ASN1_INTEGER_cmp(serial, X509_get_serialNumber(cert)) == 0) {
cp = X509_NAME_oneline(issuer, NULL, 0);
ERR(NULL, "Cert verify CRL: certificate with serial %ld (0x%lX) revoked per CRL from issuer %s.",
serial, serial, cp);
OPENSSL_free(cp);
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_CERT_REVOKED);
ret = -1;
goto cleanup;
}
}
}
cleanup:
X509_STORE_CTX_free(store_ctx);
X509_OBJECT_free(obj);
return ret;
}
static int
nc_server_tls_ts_ref_get_certs(const char *referenced_name, struct nc_certificate **certs, uint16_t *cert_count)
{
uint16_t i;
struct nc_truststore *ts = &server_opts.truststore;
*certs = NULL;
*cert_count = 0;
/* lookup name */
for (i = 0; i < ts->cert_bag_count; i++) {
if (!strcmp(referenced_name, ts->cert_bags[i].name)) {
break;
}
}
if (i == ts->cert_bag_count) {
ERR(NULL, "Truststore entry \"%s\" not found.", referenced_name);
return -1;
}
*certs = ts->cert_bags[i].certs;
*cert_count = ts->cert_bags[i].cert_count;
return 0;
}
/* In case a CA chain verification failed an end-entity certificate must match.
* The meaning of local_or_referenced is that it states, which end-entity certificates to check
* (1 = current endpoint's, 2 = referenced endpoint's).
*/
static int
nc_server_tls_do_preverify(struct nc_session *session, X509_STORE_CTX *x509_ctx, int local_or_referenced)
{
X509_STORE *store;
struct nc_cert_grouping *ee_certs;
int i, ret;
X509 *cert;
struct nc_certificate *certs;
uint16_t cert_count;
store = X509_STORE_CTX_get0_store(x509_ctx);
if (!store) {
ERR(session, "Error getting store from context (%s).", ERR_reason_error_string(ERR_get_error()));
return -1;
}
/* get the data from the store */
ee_certs = X509_STORE_get_ex_data(store, local_or_referenced);
if (!ee_certs) {
ERR(session, "Error getting data from store (%s).", ERR_reason_error_string(ERR_get_error()));
return -1;
}
if (ee_certs->store == NC_STORE_LOCAL) {
/* local definition */
certs = ee_certs->certs;
cert_count = ee_certs->cert_count;
} else {
/* truststore reference */
if (nc_server_tls_ts_ref_get_certs(ee_certs->ts_ref, &certs, &cert_count)) {
ERR(NULL, "Error getting end-entity certificates from the truststore reference \"%s\".", ee_certs->ts_ref);
return -1;
}
}
for (i = 0; i < cert_count; i++) {
cert = base64der_to_cert(certs[i].data);
ret = cert_pubkey_match(session->opts.server.client_cert, cert);
X509_free(cert);
if (ret) {
/* we are just overriding the failed standard certificate verification (preverify_ok == 0),
* this callback will be called again with the same current certificate and preverify_ok == 1 */
VRB(session, "Cert verify: fail (%s), but the end-entity certificate is trusted, continuing.",
X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509_ctx)));
X509_STORE_CTX_set_error(x509_ctx, X509_V_OK);
return 1;
}
}
return 0;
}
static int
nc_tlsclb_verify(int preverify_ok, X509_STORE_CTX *x509_ctx)
{
X509_NAME *subject;
X509_NAME *issuer;
X509 *cert;
char *cp;
X509_STORE *store;
STACK_OF(X509) * cert_stack;
struct nc_session *session;
struct nc_server_tls_opts *opts;
struct nc_endpt *referenced_endpt;
int rc, depth;
store = X509_STORE_CTX_get0_store(x509_ctx);
if (!store) {
ERR(NULL, "Error getting store from context (%s).", ERR_reason_error_string(ERR_get_error()));
return 0;
}
/* get session from the store */
session = X509_STORE_get_ex_data(store, 0);
if (!session) {
ERR(session, "Error getting session from store (%s).", ERR_reason_error_string(ERR_get_error()));
return 0;
}
opts = session->data;
/* get the last certificate, that is the peer (client) certificate */
if (!session->opts.server.client_cert) {
cert_stack = X509_STORE_CTX_get1_chain(x509_ctx);
session->opts.server.client_cert = sk_X509_value(cert_stack, 0);
X509_up_ref(session->opts.server.client_cert);
sk_X509_pop_free(cert_stack, X509_free);
}
/* standard certificate verification failed, so an end-entity client cert must match to continue */
if (!preverify_ok) {
/* check current endpoint's end-entity certs */
rc = nc_server_tls_do_preverify(session, x509_ctx, 1);
if (rc == -1) {
return 0;
} else if (rc == 1) {
return 1;
}
/* no match, continue */
if (opts->referenced_endpt_name) {
/* check referenced endpoint's end-entity certs */
rc = nc_server_tls_do_preverify(session, x509_ctx, 2);
if (rc == -1) {
return 0;
} else if (rc == 1) {
return 1;
}
}
/* no match, fail */
ERR(session, "Cert verify: fail (%s).", X509_verify_cert_error_string(X509_STORE_CTX_get_error(x509_ctx)));
return 0;
}
/* print cert verify info */
depth = X509_STORE_CTX_get_error_depth(x509_ctx);
VRB(session, "Cert verify: depth %d.", depth);
cert = X509_STORE_CTX_get_current_cert(x509_ctx);
subject = X509_get_subject_name(cert);
issuer = X509_get_issuer_name(cert);
cp = X509_NAME_oneline(subject, NULL, 0);
VRB(session, "Cert verify: subject: %s.", cp);
OPENSSL_free(cp);
cp = X509_NAME_oneline(issuer, NULL, 0);
VRB(session, "Cert verify: issuer: %s.", cp);
OPENSSL_free(cp);
/* check if the current certificate is revoked if CRL is set */
if (opts->crl_store) {
rc = nc_server_tls_check_crl(opts->crl_store, x509_ctx, cert, subject, issuer);
if (rc) {
return 0;
}
}
/* cert-to-name already successful */
if (session->username) {
return 1;
}
/* cert-to-name */
rc = nc_tls_cert_to_name(session, opts->ctn, cert);
if (rc == -1) {
/* fatal error */
depth = 0;
goto fail;
} else if ((rc == 1) && !opts->referenced_endpt_name) {
/* no match found and no referenced endpoint */
goto fail;
} else if ((rc == 1) && opts->referenced_endpt_name) {
/* no match found, but has a referenced endpoint so try it */
if (nc_server_get_referenced_endpt(opts->referenced_endpt_name, &referenced_endpt)) {
/* fatal error */
ERRINT;
depth = 0;
goto fail;
}
rc = nc_tls_cert_to_name(session, referenced_endpt->opts.tls->ctn, cert);
if (rc) {
if (rc == -1) {
/* fatal error */
depth = 0;
}
/* rc == 1 is a normal CTN fail (no match found) */
goto fail;
}
}
VRB(session, "Cert verify CTN: new client username recognized as \"%s\".", session->username);
if (server_opts.user_verify_clb && !server_opts.user_verify_clb(session)) {
VRB(session, "Cert verify: user verify callback revoked authorization.");
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_APPLICATION_VERIFICATION);
return 0;
}
return 1;
fail:
if (depth > 0) {
VRB(session, "Cert verify CTN: cert fail, cert-to-name will continue on the next cert in chain.");
return 1;
}
VRB(session, "Cert-to-name unsuccessful, dropping the new client.");
X509_STORE_CTX_set_error(x509_ctx, X509_V_ERR_APPLICATION_VERIFICATION);
return 0;
}
API const X509 *
nc_session_get_client_cert(const struct nc_session *session)
{
if (!session || (session->side != NC_SERVER)) {
ERRARG(session, "session");
return NULL;
}
return session->opts.server.client_cert;
}
API void
nc_server_tls_set_verify_clb(int (*verify_clb)(const struct nc_session *session))
{
server_opts.user_verify_clb = verify_clb;
}
static int
nc_server_tls_ks_ref_get_cert_key(const char *referenced_key_name, const char *referenced_cert_name,
char **privkey_data, NC_PRIVKEY_FORMAT *privkey_type, char **cert_data)
{
uint16_t i, j;
struct nc_keystore *ks = &server_opts.keystore;
*privkey_data = NULL;
*cert_data = NULL;
/* lookup name */
for (i = 0; i < ks->asym_key_count; i++) {
if (!strcmp(referenced_key_name, ks->asym_keys[i].name)) {
break;
}
}
if (i == ks->asym_key_count) {
ERR(NULL, "Keystore entry \"%s\" not found.", referenced_key_name);
return -1;
}
for (j = 0; j < ks->asym_keys[i].cert_count; j++) {
if (!strcmp(referenced_cert_name, ks->asym_keys[i].certs[j].name)) {
break;
}
}
if (j == ks->asym_keys[i].cert_count) {
ERR(NULL, "Keystore certificate entry \"%s\" associated with the key \"%s\" not found.",
referenced_cert_name, referenced_key_name);
return -1;
}
*privkey_data = ks->asym_keys[i].privkey_data;
*privkey_type = ks->asym_keys[i].privkey_type;
*cert_data = ks->asym_keys[i].certs[j].data;
return 0;
}
static int
nc_tls_ctx_set_server_cert_key(SSL_CTX *tls_ctx, struct nc_server_tls_opts *opts)
{
char *privkey_data = NULL, *cert_data = NULL;
int ret = 0;
NC_PRIVKEY_FORMAT privkey_type;
X509 *cert = NULL;
EVP_PKEY *pkey = NULL;
NC_CHECK_ARG_RET(NULL, tls_ctx, opts, -1);
/* get data needed for setting the server cert */
if (opts->store == NC_STORE_LOCAL) {
/* local definition */
cert_data = opts->cert_data;
privkey_data = opts->privkey_data;
privkey_type = opts->privkey_type;
} else {
/* keystore */
ret = nc_server_tls_ks_ref_get_cert_key(opts->key_ref, opts->cert_ref, &privkey_data, &privkey_type, &cert_data);
if (ret) {
ERR(NULL, "Getting server certificate from the keystore reference \"%s\" failed.", opts->key_ref);
return -1;
}
}
if (!cert_data || !privkey_data) {
ERR(NULL, "Server certificate not configured.");
ret = -1;
goto cleanup;
}
/* load the cert */
cert = base64der_to_cert(cert_data);
if (!cert) {
ERR(NULL, "Converting certificate data to certificate format failed.");
ret = -1;
goto cleanup;
}
/* set server cert */
ret = SSL_CTX_use_certificate(tls_ctx, cert);
if (ret != 1) {
ERR(NULL, "Loading the server certificate failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
/* load the private key */
pkey = base64der_to_privatekey(privkey_data, nc_privkey_format_to_str(privkey_type));
if (!pkey) {
ERR(NULL, "Converting private key data to private key format failed.");
ret = -1;
goto cleanup;
}
/* set server key */
ret = SSL_CTX_use_PrivateKey(tls_ctx, pkey);
if (ret != 1) {
ERR(NULL, "Loading the server private key failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
ret = 0;
cleanup:
X509_free(cert);
EVP_PKEY_free(pkey);
return ret;
}
static int
tls_store_add_trusted_cert(X509_STORE *cert_store, const char *cert_data)
{
X509 *cert;
cert = base64der_to_cert(cert_data);
if (!cert) {
ERR(NULL, "Loading a trusted certificate (data \"%s\") failed (%s).", cert_data,
ERR_reason_error_string(ERR_get_error()));
return -1;
}
/* add the trusted certificate */
if (X509_STORE_add_cert(cert_store, cert) != 1) {
ERR(NULL, "Adding a trusted certificate failed (%s).", ERR_reason_error_string(ERR_get_error()));
X509_free(cert);
return -1;
}
X509_free(cert);
return 0;
}
static int
nc_tls_store_set_trusted_certs(X509_STORE *cert_store, struct nc_cert_grouping *ca_certs)
{
uint16_t i;
struct nc_certificate *certs;
uint16_t cert_count;
if (ca_certs->store == NC_STORE_LOCAL) {
/* local definition */
certs = ca_certs->certs;
cert_count = ca_certs->cert_count;
} else {
/* truststore */
if (nc_server_tls_ts_ref_get_certs(ca_certs->ts_ref, &certs, &cert_count)) {
ERR(NULL, "Error getting certificate-authority certificates from the truststore reference \"%s\".", ca_certs->ts_ref);
return -1;
}
}
for (i = 0; i < cert_count; i++) {
if (tls_store_add_trusted_cert(cert_store, certs[i].data)) {
return -1;
}
}
return 0;
}
static int
nc_server_tls_crl_path(struct nc_session *session, const char *crl_path, X509_STORE *store)
{
int ret = 0;
X509_CRL *crl = NULL;
FILE *f;
f = fopen(crl_path, "r");
if (!f) {
ERR(session, "Unable to open CRL file \"%s\".", crl_path);
return -1;
}
/* try DER first */
crl = d2i_X509_CRL_fp(f, NULL);
if (crl) {
/* success */
goto ok;
}
/* DER failed, try PEM */
rewind(f);
crl = PEM_read_X509_CRL(f, NULL, NULL, NULL);
if (!crl) {
ERR(session, "Reading CRL from file \"%s\" failed.", crl_path);
ret = -1;
goto cleanup;
}
ok:
ret = X509_STORE_add_crl(store, crl);
if (!ret) {
ERR(session, "Error adding CRL to store (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
/* ok */
ret = 0;
cleanup:
fclose(f);
X509_CRL_free(crl);
return ret;
}
static size_t
nc_server_tls_curl_cb(char *ptr, size_t size, size_t nmemb, void *userdata)
{
struct nc_curl_data *data;
size = nmemb;
data = (struct nc_curl_data *)userdata;
data->data = nc_realloc(data->data, data->size + size);
NC_CHECK_ERRMEM_RET(!data->data, 0);
memcpy(&data->data[data->size], ptr, size);
data->size += size;
return size;
}
static int
nc_server_tls_curl_init(struct nc_session *session, CURL **handle, struct nc_curl_data *data)
{
NC_CHECK_ARG_RET(session, handle, data, -1);
*handle = NULL;
*handle = curl_easy_init();
if (!*handle) {
ERR(session, "Initializing CURL failed.");
return -1;
}
if (curl_easy_setopt(*handle, CURLOPT_WRITEFUNCTION, nc_server_tls_curl_cb)) {
ERR(session, "Setting curl callback failed.");
return -1;
}
if (curl_easy_setopt(*handle, CURLOPT_WRITEDATA, data)) {
ERR(session, "Setting curl callback data failed.");
return -1;
}
return 0;
}
static int
nc_server_tls_curl_fetch(struct nc_session *session, CURL *handle, const char *url)
{
char err_buf[CURL_ERROR_SIZE];
/* set uri */
if (curl_easy_setopt(handle, CURLOPT_URL, url)) {
ERR(session, "Setting URI \"%s\" to download CRL from failed.", url);
return -1;
}
/* set err buf */
if (curl_easy_setopt(handle, CURLOPT_ERRORBUFFER, err_buf)) {
ERR(session, "Setting CURL error buffer option failed.");
return -1;
}
/* download */
if (curl_easy_perform(handle)) {
ERR(session, "Downloading CRL from \"%s\" failed (%s).", url, err_buf);
return -1;
}
return 0;
}
static int
nc_server_tls_add_crl_to_store(struct nc_session *session, struct nc_curl_data *downloaded, X509_STORE *store)
{
int ret = 0;
X509_CRL *crl = NULL;
BIO *bio = NULL;
/* try DER first */
crl = d2i_X509_CRL(NULL, (const unsigned char **) &downloaded->data, downloaded->size);
if (crl) {
/* it was DER */
goto ok;
}
/* DER failed, try PEM next */
bio = BIO_new_mem_buf(downloaded->data, downloaded->size);
if (!bio) {
ERR(session, "Creating new bio failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
/* try to parse PEM from the downloaded data */
crl = PEM_read_bio_X509_CRL(bio, NULL, NULL, NULL);
if (!crl) {
ERR(session, "Reading downloaded CRL failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
ok:
/* we obtained the CRL, now add it to the CRL store */
ret = X509_STORE_add_crl(store, crl);
if (!ret) {
ERR(session, "Error adding CRL to store (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
/* ok */
ret = 0;
cleanup:
X509_CRL_free(crl);
BIO_free(bio);
return ret;
}
static int
nc_server_tls_crl_url(struct nc_session *session, const char *url, X509_STORE *store)
{
int ret = 0;
CURL *handle = NULL;
struct nc_curl_data downloaded = {0};
/* init curl */
ret = nc_server_tls_curl_init(session, &handle, &downloaded);
if (ret) {
goto cleanup;
}
VRB(session, "Downloading CRL from \"%s\".", url);
/* download the CRL */
ret = nc_server_tls_curl_fetch(session, handle, url);
if (ret) {
goto cleanup;
}
/* convert the downloaded data to CRL and add it to the store */
ret = nc_server_tls_add_crl_to_store(session, &downloaded, store);
if (ret) {
goto cleanup;
}
cleanup:
curl_easy_cleanup(handle);
return ret;
}
static int
nc_server_tls_crl_cert_ext(struct nc_session *session, X509_STORE *cert_store, X509_STORE *crl_store)
{
int ret = 0, i, j, k, gtype;
CURL *handle = NULL;
struct nc_curl_data downloaded = {0};
STACK_OF(X509_OBJECT) * objs;
X509_OBJECT *obj;
X509 *cert;
STACK_OF(DIST_POINT) * dist_points;
DIST_POINT *dist_point;
GENERAL_NAMES *general_names;
GENERAL_NAME *general_name;
ASN1_STRING *asn_string_uri;
const char *crl_distpoint_uri;
/* init curl */
ret = nc_server_tls_curl_init(session, &handle, &downloaded);
if (ret) {
goto cleanup;
}
/* treat all entries in the cert_store as X509_OBJECTs */
objs = X509_STORE_get0_objects(cert_store);
if (!objs) {
ERR(session, "Getting certificates from store failed (%s).", ERR_reason_error_string(ERR_get_error()));
ret = -1;
goto cleanup;
}
/* iterate over all the CAs */
for (i = 0; i < sk_X509_OBJECT_num(objs); i++) {
obj = sk_X509_OBJECT_value(objs, i);
cert = X509_OBJECT_get0_X509(obj);
if (!cert) {
/* the object on this index was not a certificate */
continue;
}
/* get all the distribution points for this CA */
dist_points = X509_get_ext_d2i(cert, NID_crl_distribution_points, NULL, NULL);
/* iterate over all the dist points (there can be multiple for a single cert) */
for (j = 0; j < sk_DIST_POINT_num(dist_points); j++) {
dist_point = sk_DIST_POINT_value(dist_points, j);
if (!dist_point) {
continue;
}
general_names = dist_point->distpoint->name.fullname;
/* iterate over all the GeneralesNames in the distribution point */
for (k = 0; k < sk_GENERAL_NAME_num(general_names); k++) {
general_name = sk_GENERAL_NAME_value(general_names, k);
asn_string_uri = GENERAL_NAME_get0_value(general_name, &gtype);
/* check if the general name is a URI and has a valid length */
if ((gtype != GEN_URI) || (ASN1_STRING_length(asn_string_uri) <= 6)) {
continue;
}
crl_distpoint_uri = (const char *) ASN1_STRING_get0_data(asn_string_uri);
VRB(session, "Downloading CRL from \"%s\".", crl_distpoint_uri);
/* download the CRL */
ret = nc_server_tls_curl_fetch(session, handle, crl_distpoint_uri);
if (ret) {
/* failed to download the CRL from this entry, try th next */
continue;
}
/* convert the downloaded data to CRL and add it to the store */
ret = nc_server_tls_add_crl_to_store(session, &downloaded, crl_store);
if (ret) {
goto cleanup;
}
/* the CRL was downloaded, no need to download it again using different protocol */
break;
}
}
}
cleanup:
curl_easy_cleanup(handle);
return ret;
}
static int
nc_tls_store_set_crl(struct nc_session *session, struct nc_server_tls_opts *opts, X509_STORE *store)
{
if (!opts->crl_store) {
/* first call on this endpoint */
opts->crl_store = X509_STORE_new();
NC_CHECK_ERRMEM_GOTO(!opts->crl_store, , fail);
}
if (opts->crl_path) {
if (nc_server_tls_crl_path(session, opts->crl_path, opts->crl_store)) {
goto fail;
}
} else if (opts->crl_url) {
if (nc_server_tls_crl_url(session, opts->crl_url, opts->crl_store)) {
goto fail;
}
} else {
if (nc_server_tls_crl_cert_ext(session, store, opts->crl_store)) {
goto fail;
}
}
return 0;
fail:
return -1;
}
static int
nc_server_tls_accept_check(int accept_ret, struct nc_session *session)
{
int verify;
/* check certificate verification result */
verify = SSL_get_verify_result(session->ti.tls);
switch (verify) {
case X509_V_OK:
if (accept_ret == 1) {
VRB(session, "Client certificate verified.");
}
break;
default:
ERR(session, "Client certificate error (%s).", X509_verify_cert_error_string(verify));
}
if (accept_ret != 1) {
switch (SSL_get_error(session->ti.tls, accept_ret)) {
case SSL_ERROR_SYSCALL:
ERR(session, "SSL accept failed (%s).", strerror(errno));
break;
case SSL_ERROR_SSL:
ERR(session, "SSL accept failed (%s).", ERR_reason_error_string(ERR_get_error()));
break;
default:
ERR(session, "SSL accept failed.");
break;
}
}
return accept_ret;
}
int
nc_accept_tls_session(struct nc_session *session, struct nc_server_tls_opts *opts, int sock, int timeout)
{
X509_STORE *cert_store;
SSL_CTX *tls_ctx;
int ret;
struct timespec ts_timeout;
struct nc_endpt *referenced_endpt = NULL;
/* SSL_CTX */
tls_ctx = SSL_CTX_new(TLS_server_method());
if (!tls_ctx) {
ERR(session, "Failed to create TLS context.");
goto error;
}
SSL_CTX_set_verify(tls_ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, nc_tlsclb_verify);
if (nc_tls_ctx_set_server_cert_key(tls_ctx, opts)) {
goto error;
}
/* X509_STORE, managed (freed) with the context */
cert_store = X509_STORE_new();
if (!cert_store) {
ERR(session, "Creating certificate store failed (%s).", ERR_reason_error_string(ERR_get_error()));
goto error;
}
/* store the session, retrieve it when needed */
ret = X509_STORE_set_ex_data(cert_store, 0, session);
if (!ret) {
ERR(session, "Setting certificate store data failed (%s).", ERR_reason_error_string(ERR_get_error()));
goto error;
}
/* set end-entity certs as cert store data, retrieve them if verification fails later */
ret = X509_STORE_set_ex_data(cert_store, 1, &opts->ee_certs);
if (!ret) {
ERR(session, "Setting certificate store data failed (%s).", ERR_reason_error_string(ERR_get_error()));
goto error;
}
/* do the same for referenced endpoint's end entity certs */
if (opts->referenced_endpt_name) {
if (nc_server_get_referenced_endpt(opts->referenced_endpt_name, &referenced_endpt)) {
ERRINT;
goto error;
}
ret = X509_STORE_set_ex_data(cert_store, 2, &referenced_endpt->opts.tls->ee_certs);
if (!ret) {
ERR(session, "Setting certificate store data failed (%s).", ERR_reason_error_string(ERR_get_error()));
goto error;
}
}
/* set store to the context */
SSL_CTX_set_cert_store(tls_ctx, cert_store);
/* set certificate authority certs */
if (nc_tls_store_set_trusted_certs(cert_store, &opts->ca_certs)) {
goto error;
}
/* set referenced endpoint's CA certs if set */
if (opts->referenced_endpt_name) {
if (nc_tls_store_set_trusted_certs(cert_store, &referenced_endpt->opts.tls->ca_certs)) {
goto error;
}
}
/* set Certificate Revocation List if configured */
if (opts->crl_path || opts->crl_url || opts->crl_cert_ext) {
if (nc_tls_store_set_crl(session, opts, cert_store)) {
goto error;
}
}
session->ti_type = NC_TI_OPENSSL;
session->ti.tls = SSL_new(tls_ctx);
/* context can be freed already, trusted certs must be freed manually */
SSL_CTX_free(tls_ctx);
tls_ctx = NULL;
if (!session->ti.tls) {
ERR(session, "Failed to create TLS structure from context.");
goto error;
}
/* set TLS versions for the current SSL session */
if (opts->tls_versions) {
if (!(opts->tls_versions & NC_TLS_VERSION_10)) {
SSL_set_options(session->ti.tls, SSL_OP_NO_TLSv1);
}
if (!(opts->tls_versions & NC_TLS_VERSION_11)) {
SSL_set_options(session->ti.tls, SSL_OP_NO_TLSv1_1);
}
if (!(opts->tls_versions & NC_TLS_VERSION_12)) {
SSL_set_options(session->ti.tls, SSL_OP_NO_TLSv1_2);
}
if (!(opts->tls_versions & NC_TLS_VERSION_13)) {
SSL_set_options(session->ti.tls, SSL_OP_NO_TLSv1_3);
}
}
/* set TLS cipher suites */
if (opts->ciphers) {
/* set for TLS1.2 and lower */
SSL_set_cipher_list(session->ti.tls, opts->ciphers);
/* set for TLS1.3 */
SSL_set_ciphersuites(session->ti.tls, opts->ciphers);
}
SSL_set_fd(session->ti.tls, sock);
sock = -1;
SSL_set_mode(session->ti.tls, SSL_MODE_AUTO_RETRY);
if (timeout > -1) {
nc_timeouttime_get(&ts_timeout, timeout);
}
while (((ret = SSL_accept(session->ti.tls)) == -1) && (SSL_get_error(session->ti.tls, ret) == SSL_ERROR_WANT_READ)) {
usleep(NC_TIMEOUT_STEP);
if ((timeout > -1) && (nc_timeouttime_cur_diff(&ts_timeout) < 1)) {
ERR(session, "SSL accept timeout.");
return 0;
}
}
if (nc_server_tls_accept_check(ret, session) != 1) {
return -1;
}
return 1;
error:
if (sock > -1) {
close(sock);
}
SSL_CTX_free(tls_ctx);
return -1;
}