From 3054880e09bbff8a885d44f2a304db9a63da4d53 Mon Sep 17 00:00:00 2001
From: Christopher Faulet <cfaulet@qualys.com>
Date: Thu, 11 Jun 2015 13:39:32 +0200
Subject: [PATCH] MINOR: ssl: Export functions to manipulate generated
 certificates

Following functions are now available in the SSL public API:

  * ssl_sock_create_cert
  * ssl_sock_get_generated_cert
  * ssl_sock_set_generated_cert
  * ssl_sock_generated_cert_serial

These functions could be used to create a certificate by hand, set it in the
cache used to store generated certificates and retrieve it. Here is an example
(pseudo code):

  X509        *cacert     = ...;
  EVP_PKEY    *capkey     = ...;
  char        *servername = ...;
  unsigned int serial;

  serial = ssl_sock_generated_cert_serial(servername, strlen(servername));
  if (!ssl_sock_get_generated_cert(serial, cacert)) {
      SSL_CTX *ctx = ssl_sock_create_cert(servername, serial, cacert, capkey);
      ssl_sock_set_generated_cert(ctx, serial, cacert);
  }
---
 include/proto/ssl_sock.h |  5 ++++
 src/ssl_sock.c           | 57 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/include/proto/ssl_sock.h b/include/proto/ssl_sock.h
index 7a9e98823..ec616dca9 100644
--- a/include/proto/ssl_sock.h
+++ b/include/proto/ssl_sock.h
@@ -69,6 +69,11 @@ void tlskeys_finalize_config(void);
 int ssl_sock_load_global_dh_param_from_file(const char *filename);
 #endif
 
+SSL_CTX *ssl_sock_create_cert(const char *servername, unsigned int serial, X509 *cacert, EVP_PKEY *capkey);
+SSL_CTX *ssl_sock_get_generated_cert(unsigned int serial, X509 *cacert);
+void ssl_sock_set_generated_cert(SSL_CTX *ctx, unsigned int serial, X509 *cacert);
+unsigned int ssl_sock_generated_cert_serial(void *data, size_t len);
+
 #endif /* _PROTO_SSL_SOCK_H */
 
 /*
diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 75876a26d..dfc992549 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -1003,7 +1003,9 @@ static int ssl_sock_advertise_alpn_protos(SSL *s, const unsigned char **out,
 }
 #endif
 
-static SSL_CTX *
+/* Create a X509 certificate with the specified servername and serial. This
+ * function returns a SSL_CTX object or NULL if an error occurs. */
+SSL_CTX *
 ssl_sock_create_cert(const char *servername, unsigned int serial, X509 *cacert, EVP_PKEY *capkey)
 {
 	SSL_CTX      *ssl_ctx = NULL;
@@ -1107,6 +1109,44 @@ ssl_sock_create_cert(const char *servername, unsigned int serial, X509 *cacert,
 	return NULL;
 }
 
+/* Do a lookup for a certificate in the LRU cache used to store generated
+ * certificates. */
+SSL_CTX *
+ssl_sock_get_generated_cert(unsigned int serial, X509 *cacert)
+{
+	struct lru64 *lru = NULL;
+
+	if (ssl_ctx_lru_tree) {
+		lru = lru64_lookup(serial, ssl_ctx_lru_tree, cacert, 0);
+		if (lru && lru->domain)
+			return (SSL_CTX *)lru->data;
+	}
+	return NULL;
+}
+
+/* Set a certificate int the LRU cache used to store generated certificate. */
+void
+ssl_sock_set_generated_cert(SSL_CTX *ssl_ctx, unsigned int serial, X509 *cacert)
+{
+	struct lru64 *lru = NULL;
+
+	if (ssl_ctx_lru_tree) {
+		lru = lru64_get(serial, ssl_ctx_lru_tree, cacert, 0);
+		if (!lru)
+			return;
+		if (lru->domain && lru->data)
+			lru->free((SSL_CTX *)lru->data);
+		lru64_commit(lru, ssl_ctx, cacert, 0, (void (*)(void *))SSL_CTX_free);
+	}
+}
+
+/* Compute the serial that will be used to create/set/get a certificate. */
+unsigned int
+ssl_sock_generated_cert_serial(void *data, size_t len)
+{
+	return XXH32(data, len, ssl_ctx_lru_seed);
+}
+
 static SSL_CTX *
 ssl_sock_generate_certificate(const char *servername, struct bind_conf *bind_conf)
 {
@@ -1146,6 +1186,21 @@ static int ssl_sock_switchctx_cbk(SSL *ssl, int *al, struct bind_conf *s)
 
 	servername = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
 	if (!servername) {
+		struct sockaddr to;
+		int             fd;
+
+		if (s->generate_certs &&
+		    (fd = SSL_get_fd(ssl)) != -1 &&
+		    tcp_get_dst(fd, &to, sizeof(to), 0) != -1) {
+			unsigned int serial = ssl_sock_generated_cert_serial(&to, sizeof(to));
+			SSL_CTX *ctx = ssl_sock_get_generated_cert(serial, s->ca_sign_cert);
+			if (ctx) {
+				/* switch ctx */
+				SSL_set_SSL_CTX(ssl, ctx);
+				return SSL_TLSEXT_ERR_OK;
+			}
+		}
+
 		return (s->strict_sni ?
 			SSL_TLSEXT_ERR_ALERT_FATAL :
 			SSL_TLSEXT_ERR_NOACK);