Merge pull request #5620 from gstrauss/dn_hints
Add accessors to config DN hints for cert request
diff --git a/ChangeLog.d/mbedtls_ssl_dn_hint.txt b/ChangeLog.d/mbedtls_ssl_dn_hint.txt
new file mode 100644
index 0000000..f569a36
--- /dev/null
+++ b/ChangeLog.d/mbedtls_ssl_dn_hint.txt
@@ -0,0 +1,3 @@
+Features
+ * Add accessors to configure DN hints for certificate request:
+ mbedtls_ssl_conf_dn_hints() and mbedtls_ssl_set_hs_dn_hints()
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index ad7b8f0..b3b5d47 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1496,6 +1496,10 @@
#if defined(MBEDTLS_SSL_SRV_C)
mbedtls_ssl_hs_cb_t MBEDTLS_PRIVATE(f_cert_cb); /*!< certificate selection callback */
#endif /* MBEDTLS_SSL_SRV_C */
+
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+ const mbedtls_x509_crt *MBEDTLS_PRIVATE(dn_hints);/*!< acceptable client cert issuers */
+#endif
};
struct mbedtls_ssl_context
@@ -3128,6 +3132,26 @@
mbedtls_x509_crt *ca_chain,
mbedtls_x509_crl *ca_crl );
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+/**
+ * \brief Set DN hints sent to client in CertificateRequest message
+ *
+ * \note If not set, subject distinguished names (DNs) are taken
+ * from \c mbedtls_ssl_conf_ca_chain()
+ * or \c mbedtls_ssl_set_hs_ca_chain())
+ *
+ * \param conf SSL configuration
+ * \param crt crt chain whose subject DNs are issuer DNs of client certs
+ * from which the client should select client peer certificate.
+ */
+static inline
+void mbedtls_ssl_conf_dn_hints( mbedtls_ssl_config *conf,
+ const mbedtls_x509_crt *crt )
+{
+ conf->MBEDTLS_PRIVATE(dn_hints) = crt;
+}
+#endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
+
#if defined(MBEDTLS_X509_TRUSTED_CERTIFICATE_CALLBACK)
/**
* \brief Set the trusted certificate callback.
@@ -3652,6 +3676,21 @@
mbedtls_x509_crt *ca_chain,
mbedtls_x509_crl *ca_crl );
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+/**
+ * \brief Set DN hints sent to client in CertificateRequest message
+ *
+ * \note Same as \c mbedtls_ssl_conf_dn_hints() but for use within
+ * the SNI callback or the certificate selection callback.
+ *
+ * \param ssl SSL context
+ * \param crt crt chain whose subject DNs are issuer DNs of client certs
+ * from which the client should select client peer certificate.
+ */
+void mbedtls_ssl_set_hs_dn_hints( mbedtls_ssl_context *ssl,
+ const mbedtls_x509_crt *crt );
+#endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
+
/**
* \brief Set authmode for the current handshake.
*
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 119826f..8230163 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -850,6 +850,9 @@
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
const unsigned char *sni_name; /*!< raw SNI */
size_t sni_name_len; /*!< raw SNI len */
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+ const mbedtls_x509_crt *dn_hints; /*!< acceptable client cert issuers */
+#endif
#endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
};
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 5fa02d2..1969738 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1472,6 +1472,14 @@
ssl->handshake->sni_ca_crl = ca_crl;
}
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+void mbedtls_ssl_set_hs_dn_hints( mbedtls_ssl_context *ssl,
+ const mbedtls_x509_crt *crt)
+{
+ ssl->handshake->dn_hints = crt;
+}
+#endif /* MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED */
+
void mbedtls_ssl_set_hs_authmode( mbedtls_ssl_context *ssl,
int authmode )
{
diff --git a/library/ssl_tls12_client.c b/library/ssl_tls12_client.c
index f516efa..35f11ea 100644
--- a/library/ssl_tls12_client.c
+++ b/library/ssl_tls12_client.c
@@ -2534,6 +2534,7 @@
size_t sig_alg_len;
#if defined(MBEDTLS_DEBUG_C)
unsigned char *sig_alg;
+ unsigned char *dn;
#endif
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse certificate request" ) );
@@ -2681,6 +2682,43 @@
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
+#if defined(MBEDTLS_DEBUG_C)
+ dn = buf + mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n - dn_len;
+ for( size_t i = 0, dni_len = 0; i < dn_len; i += 2 + dni_len )
+ {
+ unsigned char *p = dn + i + 2;
+ mbedtls_x509_name name;
+ mbedtls_x509_name *name_cur, *name_prv;
+ size_t asn1_len;
+ char s[MBEDTLS_X509_MAX_DN_NAME_SIZE];
+ memset( &name, 0, sizeof( name ) );
+ dni_len = MBEDTLS_GET_UINT16_BE( dn + i, 0 );
+ if( dni_len > dn_len - i - 2 ||
+ mbedtls_asn1_get_tag( &p, p + dni_len, &asn1_len,
+ MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) != 0 ||
+ mbedtls_x509_get_name( &p, p + asn1_len, &name ) != 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
+ mbedtls_ssl_send_alert_message(
+ ssl,
+ MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+ MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
+ return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
+ MBEDTLS_SSL_DEBUG_MSG( 3,
+ ( "DN hint: %.*s",
+ mbedtls_x509_dn_gets( s, sizeof(s), &name ), s ) );
+ name_cur = name.next;
+ while( name_cur != NULL )
+ {
+ name_prv = name_cur;
+ name_cur = name_cur->next;
+ mbedtls_platform_zeroize( name_prv, sizeof( mbedtls_x509_name ) );
+ mbedtls_free( name_prv );
+ }
+ }
+#endif
+
exit:
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= parse certificate request" ) );
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index 21e5cda..0952872 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -2489,6 +2489,16 @@
* `mbedtls_ssl_conf_ca_cb()`, then the
* CertificateRequest is currently left empty. */
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
+ if( ssl->handshake->dn_hints != NULL )
+ crt = ssl->handshake->dn_hints;
+ else
+#endif
+ if( ssl->conf->dn_hints != NULL )
+ crt = ssl->conf->dn_hints;
+ else
+#endif
#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
if( ssl->handshake->sni_ca_chain != NULL )
crt = ssl->handshake->sni_ca_chain;
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index 4251817..5231fe4 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -116,6 +116,7 @@
#define DFL_CID_VALUE_RENEGO NULL
#define DFL_AUTH_MODE -1
#define DFL_CERT_REQ_CA_LIST MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED
+#define DFL_CERT_REQ_DN_HINT 0
#define DFL_MFL_CODE MBEDTLS_SSL_MAX_FRAG_LEN_NONE
#define DFL_TRUNC_HMAC -1
#define DFL_TICKETS MBEDTLS_SSL_SESSION_TICKETS_ENABLED
@@ -506,6 +507,7 @@
" options: none, optional, required\n" \
" cert_req_ca_list=%%d default: 1 (send ca list)\n" \
" options: 1 (send ca list), 0 (don't send)\n" \
+ " 2 (send conf dn hint), 3 (send hs dn hint)\n" \
USAGE_IO \
USAGE_KEY_OPAQUE \
"\n" \
@@ -629,6 +631,7 @@
int allow_sha1; /* flag for SHA-1 support */
int auth_mode; /* verify mode for connection */
int cert_req_ca_list; /* should we send the CA list? */
+ int cert_req_dn_hint; /* mode to set DN hints for CA list to send */
unsigned char mfl_code; /* code for maximum fragment length */
int trunc_hmac; /* accept truncated hmac? */
int tickets; /* enable / disable session tickets */
@@ -1597,6 +1600,7 @@
opt.allow_sha1 = DFL_SHA1;
opt.auth_mode = DFL_AUTH_MODE;
opt.cert_req_ca_list = DFL_CERT_REQ_CA_LIST;
+ opt.cert_req_dn_hint = DFL_CERT_REQ_DN_HINT;
opt.mfl_code = DFL_MFL_CODE;
opt.trunc_hmac = DFL_TRUNC_HMAC;
opt.tickets = DFL_TICKETS;
@@ -1923,8 +1927,13 @@
else if( strcmp( p, "cert_req_ca_list" ) == 0 )
{
opt.cert_req_ca_list = atoi( q );
- if( opt.cert_req_ca_list < 0 || opt.cert_req_ca_list > 1 )
+ if( opt.cert_req_ca_list < 0 || opt.cert_req_ca_list > 3 )
goto usage;
+ if( opt.cert_req_ca_list > 1 )
+ {
+ opt.cert_req_dn_hint = opt.cert_req_ca_list;
+ opt.cert_req_ca_list = MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED;
+ }
}
else if( strcmp( p, "max_frag_len" ) == 0 )
{
@@ -2732,6 +2741,16 @@
if( opt.cert_req_ca_list != DFL_CERT_REQ_CA_LIST )
mbedtls_ssl_conf_cert_req_ca_list( &conf, opt.cert_req_ca_list );
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+ /* exercise setting DN hints for server certificate request
+ * (Intended for use where the client cert expected has been signed by
+ * a specific CA which is an intermediate in a CA chain, not the root) */
+ if( opt.cert_req_dn_hint == 2 && key_cert_init2 )
+ mbedtls_ssl_conf_dn_hints( &conf, &srvcert2 );
+#endif
+#endif
+
#if defined(MBEDTLS_SSL_PROTO_DTLS)
if( opt.hs_to_min != DFL_HS_TO_MIN || opt.hs_to_max != DFL_HS_TO_MAX )
mbedtls_ssl_conf_handshake_timeout( &conf, opt.hs_to_min, opt.hs_to_max );
@@ -3332,6 +3351,20 @@
}
#endif
+#if defined(MBEDTLS_X509_CRT_PARSE_C)
+#if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
+#if defined(MBEDTLS_KEY_EXCHANGE_CERT_REQ_ALLOWED_ENABLED)
+ /* exercise setting DN hints for server certificate request
+ * (Intended for use where the client cert expected has been signed by
+ * a specific CA which is an intermediate in a CA chain, not the root)
+ * (Additionally, the CA choice would typically be influenced by SNI
+ * if being set per-handshake using mbedtls_ssl_set_hs_dn_hints()) */
+ if( opt.cert_req_dn_hint == 3 && key_cert_init2 )
+ mbedtls_ssl_set_hs_dn_hints( &ssl, &srvcert2 );
+#endif
+#endif
+#endif
+
mbedtls_printf( " ok\n" );
/*
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index afabb64..af32791 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -5116,6 +5116,39 @@
-c "! mbedtls_ssl_handshake returned" \
-s "X509 - Certificate verification failed"
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+run_test "Authentication: send alt conf DN hints in CertificateRequest" \
+ "$P_SRV debug_level=3 auth_mode=optional cert_req_ca_list=2 \
+ crt_file2=data_files/server1.crt \
+ key_file2=data_files/server1.key" \
+ "$P_CLI debug_level=3 auth_mode=optional \
+ crt_file=data_files/server6.crt \
+ key_file=data_files/server6.key" \
+ 0 \
+ -c "DN hint: C=NL, O=PolarSSL, CN=PolarSSL Server 1"
+
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+run_test "Authentication: send alt conf DN hints in CertificateRequest (2)" \
+ "$P_SRV debug_level=3 auth_mode=optional cert_req_ca_list=2 \
+ crt_file2=data_files/server2.crt \
+ key_file2=data_files/server2.key" \
+ "$P_CLI debug_level=3 auth_mode=optional \
+ crt_file=data_files/server6.crt \
+ key_file=data_files/server6.key" \
+ 0 \
+ -c "DN hint: C=NL, O=PolarSSL, CN=localhost"
+
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_2
+run_test "Authentication: send alt hs DN hints in CertificateRequest" \
+ "$P_SRV debug_level=3 auth_mode=optional cert_req_ca_list=3 \
+ crt_file2=data_files/server1.crt \
+ key_file2=data_files/server1.key" \
+ "$P_CLI debug_level=3 auth_mode=optional \
+ crt_file=data_files/server6.crt \
+ key_file=data_files/server6.key" \
+ 0 \
+ -c "DN hint: C=NL, O=PolarSSL, CN=PolarSSL Server 1"
+
# Tests for auth_mode, using CA callback, these are duplicated from the authentication tests
# When updating these tests, modify the matching authentication tests accordingly
