@@ -3347,6 +3347,7 @@ do_init_crypto_tls(struct context *c, const unsigned int flags)
to.verify_hash = options->verify_hash;
to.verify_hash_algo = options->verify_hash_algo;
to.verify_hash_depth = options->verify_hash_depth;
+ to.verify_hash_no_ca = options->verify_hash_no_ca;
#ifdef ENABLE_X509ALTUSERNAME
memcpy(to.x509_username_field, options->x509_username_field, sizeof(to.x509_username_field));
#else
@@ -2991,21 +2991,11 @@ options_postprocess_verify_ce(const struct options *options,
else
{
#ifdef ENABLE_CRYPTO_MBEDTLS
- if (!(options->ca_file))
- {
- msg(M_USAGE, "You must define CA file (--ca)");
- }
-
if (options->ca_path)
{
msg(M_USAGE, "Parameter --capath cannot be used with the mbed TLS version version of OpenVPN.");
}
-#else /* ifdef ENABLE_CRYPTO_MBEDTLS */
- if ((!(options->ca_file)) && (!(options->ca_path)))
- {
- msg(M_USAGE, "You must define CA file (--ca) or CA path (--capath)");
- }
-#endif
+#endif /* ifdef ENABLE_CRYPTO_MBEDTLS */
if (pull)
{
@@ -3737,6 +3727,13 @@ options_postprocess_mutate(struct options *o, struct env_set *es)
options_postprocess_http_proxy_override(o);
}
#endif
+ if (!o->ca_file && !o->ca_path && o->verify_hash
+ && o->verify_hash_depth == 0)
+ {
+ msg(M_INFO, "Using certificate fingerprint to verify peer (no CA "
+ "option set). ");
+ o->verify_hash_no_ca = true;
+ }
if (o->config && streq(o->config, "stdin") && o->remap_sigusr1 == SIGHUP)
{
@@ -4032,8 +4029,11 @@ options_postprocess_filechecks(struct options *options)
errs |= check_file_access_inline(options->dh_file_inline, CHKACC_FILE,
options->dh_file, R_OK, "--dh");
- errs |= check_file_access_inline(options->ca_file_inline, CHKACC_FILE,
- options->ca_file, R_OK, "--ca");
+ if (!options->verify_hash_no_ca)
+ {
+ errs |= check_file_access_inline(options->ca_file_inline, CHKACC_FILE,
+ options->ca_file, R_OK, "--ca");
+ }
errs |= check_file_access_chroot(options->chroot_dir, CHKACC_FILE,
options->ca_path, R_OK, "--capath");
@@ -604,6 +604,7 @@ struct options
struct verify_hash_list *verify_hash;
hash_algo_type verify_hash_algo;
int verify_hash_depth;
+ bool verify_hash_no_ca;
unsigned int ssl_flags; /* set to SSLF_x flags from ssl.h */
#ifdef ENABLE_PKCS11
@@ -345,6 +345,7 @@ struct tls_options
const char *remote_cert_eku;
struct verify_hash_list *verify_hash;
int verify_hash_depth;
+ bool verify_hash_no_ca;
hash_algo_type verify_hash_algo;
#ifdef ENABLE_X509ALTUSERNAME
char *x509_username_field[MAX_PARMS];
@@ -62,6 +62,22 @@ verify_callback(void *session_obj, mbedtls_x509_crt *cert, int cert_depth,
struct buffer cert_fingerprint = x509_get_sha256_fingerprint(cert, &gc);
cert_hash_remember(session, cert_depth, &cert_fingerprint);
+ if (session->opt->verify_hash_no_ca)
+ {
+ /*
+ * If we decide to verify the peer certificate based on the fingerprint
+ * we ignore wrong dates and the certificate not being trusted.
+ * Any other problem with the certificate (wrong key, bad cert,...)
+ * will still trigger an error.
+ * Clearing these flags relies on verify_cert will later rejecting a
+ * certificate that has no matching fingerprint.
+ */
+ uint32_t flags_ignore = MBEDTLS_X509_BADCERT_NOT_TRUSTED
+ | MBEDTLS_X509_BADCERT_EXPIRED
+ | MBEDTLS_X509_BADCERT_FUTURE;
+ *flags = *flags & ~flags_ignore;
+ }
+
/* did peer present cert which was signed by our root cert? */
if (*flags != 0)
{
@@ -67,7 +67,7 @@ verify_callback(int preverify_ok, X509_STORE_CTX *ctx)
cert_hash_remember(session, X509_STORE_CTX_get_error_depth(ctx), &cert_hash);
/* did peer present cert which was signed by our root cert? */
- if (!preverify_ok)
+ if (!preverify_ok && !session->opt->verify_hash_no_ca)
{
/* get the X509 name */
char *subject = x509_get_subject(current_cert, &gc);
This is implements --peer-fingerprint command to support OpenVPN authentication without involving a PKI. The current implementation in OpenVPN for peer fingerprint has been already extensively rewritten from the original submission from Jason. The commit preserved the original author since it was based on Jason code/idea. The code uses two commits to prepare the --peer-fingerprint solution as which choose to use a simple to use --peer-fingerprint directive instead of using using a --tls-verify script like the v1 of the patch proposed. The two commit preparing this are: - Extend verify-hash to allow multiple hashes - Implement peer-fingerprint to check fingerprint of peer certificate This perparing patches make this actual patch quite short. There are some lines in this patch that bear some similarity to the ones like if (!preverify_ok && !session->opt->verify_hash_no_ca) vs if (!preverify_ok && !session->opt->ca_file_none) But these similarities are one line fragments and dictated by the surrounding style and program flow, so even a complete black box implementation will likely end up with the same lines. Patch V2: Changes in V2 (by Arne Schwabe): - Only check peer certificates, not all cert levels, if you need multiple levels of certificate you should use a real CA - Use peer-fingerprint instead tls-verify on server side in example. - rename variable ca_file_none to verify_hash_no_ca - do no require --ca none but allow --ca simply to be absent when --peer-fingprint is present - adjust warnings/errors messages to also point to peer-fingerprint as valid verification method. - Fix mbed TLS version of not requiring CA not working Patch v3: Fix minor style. Remove unessary check of verify_hash_no_ca in ssl.c. Patch v4: remove the last parts of Jason's original patch. Change-Id: Ie74c3d606c5429455c293c367462244566a936e3 Signed-off-by: Arne Schwabe <arne@rfc2549.org> --- src/openvpn/init.c | 1 + src/openvpn/options.c | 26 +++++++++++++------------- src/openvpn/options.h | 1 + src/openvpn/ssl_common.h | 1 + src/openvpn/ssl_verify_mbedtls.c | 16 ++++++++++++++++ src/openvpn/ssl_verify_openssl.c | 2 +- 6 files changed, 33 insertions(+), 14 deletions(-)