=head1 NAME
SSL_CTX_dane_enable, SSL_CTX_dane_mtype_set, SSL_dane_enable,
-SSL_dane_tlsa_add, SSL_get0_dane_authority, SSL_get0_dane_tlsa
+SSL_dane_tlsa_add, SSL_get0_dane_authority, SSL_get0_dane_tlsa,
SSL_CTX_dane_set_flags, SSL_CTX_dane_clear_flags,
-SSL_dane_set_flags, SSL_dane_clear_flags -
-enable DANE TLS authentication of the remote TLS server in the local
+SSL_dane_set_flags, SSL_dane_clear_flags
+- enable DANE TLS authentication of the remote TLS server in the local
TLS client
=head1 SYNOPSIS
uint8_t mtype, uint8_t ord);
int SSL_dane_enable(SSL *s, const char *basedomain);
int SSL_dane_tlsa_add(SSL *s, uint8_t usage, uint8_t selector,
- uint8_t mtype, unsigned char *data, size_t dlen);
+ uint8_t mtype, unsigned const char *data, size_t dlen);
int SSL_get0_dane_authority(SSL *s, X509 **mcert, EVP_PKEY **mspki);
int SSL_get0_dane_tlsa(SSL *s, uint8_t *usage, uint8_t *selector,
uint8_t *mtype, unsigned const char **data,
The arguments specify the fields of the TLSA record.
The B<data> field is provided in binary (wire RDATA) form, not the hexadecimal
ASCII presentation form, with an explicit length passed via B<dlen>.
+The library takes a copy of the B<data> buffer contents and the caller may
+free the original B<data> buffer when convenient.
A return value of 0 indicates that "unusable" TLSA records (with invalid or
unsupported parameters) were provided.
A negative return value indicates an internal error in processing the record.
retrieved, and must be copied by the application if it is to be retained beyond
the lifetime of the SSL connection.
- SSL_CTX *ctx;
- SSL *ssl;
- int (*verify_cb)(int ok, X509_STORE_CTX *sctx) = NULL;
- int num_usable = 0;
- const char *nexthop_domain = "example.com";
- const char *dane_tlsa_domain = "smtp.example.com";
- uint8_t usage, selector, mtype;
-
- if ((ctx = SSL_CTX_new(TLS_client_method())) == NULL)
- /* handle error */
- if (SSL_CTX_dane_enable(ctx) <= 0)
- /* handle error */
-
- if ((ssl = SSL_new(ctx)) == NULL)
- /* handle error */
-
- if (SSL_dane_enable(ssl, dane_tlsa_domain) <= 0)
- /* handle error */
-
- /*
- * For many applications it is safe to skip DANE-EE(3) namechecks. Do not
- * disable the checks unless "unknown key share" attacks pose no risk for
- * your application.
- */
- SSL_dane_set_flags(ssl, DANE_FLAG_NO_DANE_EE_NAMECHECKS);
-
- if (!SSL_add1_host(ssl, nexthop_domain))
- /* handle error */
- SSL_set_hostflags(ssl, X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS);
-
- for (... each TLSA record ...) {
- unsigned char *data;
- size_t len;
- int ret;
-
- /* set usage, selector, mtype, data, len */
-
- /*
- * Opportunistic DANE TLS clients support only DANE-TA(2) or DANE-EE(3).
- * They treat all other certificate usages, and in particular PKIX-TA(0)
- * and PKIX-EE(1), as unusable.
- */
- switch (usage) {
- default:
- case 0: /* PKIX-TA(0) */
- case 1: /* PKIX-EE(1) */
- continue;
- case 2: /* DANE-TA(2) */
- case 3: /* DANE-EE(3) */
- break;
- }
-
- ret = SSL_dane_tlsa_add(ssl, usage, selector, mtype, data, len);
- /* free data as appropriate */
-
- if (ret < 0)
- /* handle SSL library internal error */
- else if (ret == 0)
- /* handle unusable TLSA record */
- else
- ++num_usable;
- }
-
- /*
- * At this point, the verification mode is still the default SSL_VERIFY_NONE.
- * Opportunistic DANE clients use unauthenticated TLS when all TLSA records
- * are unusable, so continue the handshake even if authentication fails.
- */
- if (num_usable == 0) {
- /* Log all records unusable? */
-
- /* Optionally set verify_cb to a suitable non-NULL callback. */
- SSL_set_verify(ssl, SSL_VERIFY_NONE, verify_cb);
- } else {
- /* At least one usable record. We expect to verify the peer */
-
- /* Optionally set verify_cb to a suitable non-NULL callback. */
-
- /*
- * Below we elect to fail the handshake when peer verification fails.
- * Alternatively, use the permissive SSL_VERIFY_NONE verification mode,
- * complete the handshake, check the verification status, and if not
- * verified disconnect gracefully at the application layer, especially if
- * application protocol supports informing the server that authentication
- * failed.
- */
- SSL_set_verify(ssl, SSL_VERIFY_PEER, verify_cb);
- }
-
- /*
- * Load any saved session for resumption, making sure that the previous
- * session applied the same security and authentication requirements that
- * would be expected of a fresh connection.
- */
-
- /* Perform SSL_connect() handshake and handle errors here */
-
- if (SSL_session_reused(ssl)) {
- if (SSL_get_verify_result(ssl) == X509_V_OK) {
- /*
- * Resumed session was originally verified, this connection is
- * authenticated.
- */
- } else {
- /*
- * Resumed session was not originally verified, this connection is not
- * authenticated.
- */
- }
- } else if (SSL_get_verify_result(ssl) == X509_V_OK) {
- const char *peername = SSL_get0_peername(ssl);
- EVP_PKEY *mspki = NULL;
-
- int depth = SSL_get0_dane_authority(ssl, NULL, &mspki);
- if (depth >= 0) {
- (void) SSL_get0_dane_tlsa(ssl, &usage, &selector, &mtype, NULL, NULL);
- printf("DANE TLSA %d %d %d %s at depth %d\n", usage, selector, mtype,
- (mspki != NULL) ? "TA public key verified certificate" :
- depth ? "matched TA certificate" : "matched EE certificate",
- depth);
- }
- if (peername != NULL) {
- /* Name checks were in scope and matched the peername */
- printf("Verified peername: %s\n", peername);
- }
- } else {
- /*
- * Not authenticated, presumably all TLSA rrs unusable, but possibly a
- * callback suppressed connection termination despite the presence of
- * usable TLSA RRs none of which matched. Do whatever is appropriate for
- * fresh unauthenticated connections.
- */
- }
+ SSL_CTX *ctx;
+ SSL *ssl;
+ int (*verify_cb)(int ok, X509_STORE_CTX *sctx) = NULL;
+ int num_usable = 0;
+ const char *nexthop_domain = "example.com";
+ const char *dane_tlsa_domain = "smtp.example.com";
+ uint8_t usage, selector, mtype;
+
+ if ((ctx = SSL_CTX_new(TLS_client_method())) == NULL)
+ /* error */
+ if (SSL_CTX_dane_enable(ctx) <= 0)
+ /* error */
+ if ((ssl = SSL_new(ctx)) == NULL)
+ /* error */
+ if (SSL_dane_enable(ssl, dane_tlsa_domain) <= 0)
+ /* error */
+
+ /*
+ * For many applications it is safe to skip DANE-EE(3) namechecks. Do not
+ * disable the checks unless "unknown key share" attacks pose no risk for
+ * your application.
+ */
+ SSL_dane_set_flags(ssl, DANE_FLAG_NO_DANE_EE_NAMECHECKS);
+
+ if (!SSL_add1_host(ssl, nexthop_domain))
+ /* error */
+ SSL_set_hostflags(ssl, X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS);
+
+ for (... each TLSA record ...) {
+ unsigned char *data;
+ size_t len;
+ int ret;
+
+ /* set usage, selector, mtype, data, len */
+
+ /*
+ * Opportunistic DANE TLS clients support only DANE-TA(2) or DANE-EE(3).
+ * They treat all other certificate usages, and in particular PKIX-TA(0)
+ * and PKIX-EE(1), as unusable.
+ */
+ switch (usage) {
+ default:
+ case 0: /* PKIX-TA(0) */
+ case 1: /* PKIX-EE(1) */
+ continue;
+ case 2: /* DANE-TA(2) */
+ case 3: /* DANE-EE(3) */
+ break;
+ }
+
+ ret = SSL_dane_tlsa_add(ssl, usage, selector, mtype, data, len);
+ /* free data as appropriate */
+
+ if (ret < 0)
+ /* handle SSL library internal error */
+ else if (ret == 0)
+ /* handle unusable TLSA record */
+ else
+ ++num_usable;
+ }
+
+ /*
+ * At this point, the verification mode is still the default SSL_VERIFY_NONE.
+ * Opportunistic DANE clients use unauthenticated TLS when all TLSA records
+ * are unusable, so continue the handshake even if authentication fails.
+ */
+ if (num_usable == 0) {
+ /* Log all records unusable? */
+
+ /* Optionally set verify_cb to a suitable non-NULL callback. */
+ SSL_set_verify(ssl, SSL_VERIFY_NONE, verify_cb);
+ } else {
+ /* At least one usable record. We expect to verify the peer */
+
+ /* Optionally set verify_cb to a suitable non-NULL callback. */
+
+ /*
+ * Below we elect to fail the handshake when peer verification fails.
+ * Alternatively, use the permissive SSL_VERIFY_NONE verification mode,
+ * complete the handshake, check the verification status, and if not
+ * verified disconnect gracefully at the application layer, especially if
+ * application protocol supports informing the server that authentication
+ * failed.
+ */
+ SSL_set_verify(ssl, SSL_VERIFY_PEER, verify_cb);
+ }
+
+ /*
+ * Load any saved session for resumption, making sure that the previous
+ * session applied the same security and authentication requirements that
+ * would be expected of a fresh connection.
+ */
+
+ /* Perform SSL_connect() handshake and handle errors here */
+
+ if (SSL_session_reused(ssl)) {
+ if (SSL_get_verify_result(ssl) == X509_V_OK) {
+ /*
+ * Resumed session was originally verified, this connection is
+ * authenticated.
+ */
+ } else {
+ /*
+ * Resumed session was not originally verified, this connection is not
+ * authenticated.
+ */
+ }
+ } else if (SSL_get_verify_result(ssl) == X509_V_OK) {
+ const char *peername = SSL_get0_peername(ssl);
+ EVP_PKEY *mspki = NULL;
+
+ int depth = SSL_get0_dane_authority(ssl, NULL, &mspki);
+ if (depth >= 0) {
+ (void) SSL_get0_dane_tlsa(ssl, &usage, &selector, &mtype, NULL, NULL);
+ printf("DANE TLSA %d %d %d %s at depth %d\n", usage, selector, mtype,
+ (mspki != NULL) ? "TA public key verified certificate" :
+ depth ? "matched TA certificate" : "matched EE certificate",
+ depth);
+ }
+ if (peername != NULL) {
+ /* Name checks were in scope and matched the peername */
+ printf("Verified peername: %s\n", peername);
+ }
+ } else {
+ /*
+ * Not authenticated, presumably all TLSA rrs unusable, but possibly a
+ * callback suppressed connection termination despite the presence of
+ * usable TLSA RRs none of which matched. Do whatever is appropriate for
+ * fresh unauthenticated connections.
+ */
+ }
=head1 NOTES
=head1 COPYRIGHT
-Copyright 2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2016-2018 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
projects / openssl.git / blobdiff