Reorganise supported signature algorithm extension processing.

Only store encoded versions of peer and configured signature algorithms.
Determine shared signature algorithms and cache the result along with NID
equivalents of each algorithm.
(backport from HEAD)

Author: snhenson

CHANGES

@@ -4,6 +4,12 @@
 
  Changes between 1.0.1 and 1.0.2 [xx XXX xxxx]
 
+  *) Update and tidy signature algorithm extension processing. Work out
+     shared signature algorithms based on preferences and peer algorithms
+     and print them out in s_client and s_server. Abort handshake if no
+     shared signature algorithms.
+     [Steve Henson]
+
   *) Add new functions to allow customised supported signature algorithms
      for SSL and SSL_CTX structures. Add options to s_client and s_server
      to support them.

apps/s_apps.h

@@ -160,7 +160,7 @@ int set_cert_key_stuff(SSL_CTX *ctx, X509 *cert, EVP_PKEY *key,
 int set_cert_key_and_authz(SSL_CTX *ctx, X509 *cert, EVP_PKEY *key,
                            unsigned char *authz, size_t authz_length);
 # endif
-int ssl_print_sigalgs(BIO *out, SSL *s);
+int ssl_print_sigalgs(BIO *out, SSL *s, int client);
 int ssl_print_curves(BIO *out, SSL *s);
 #endif
 int init_client(int *sock, char *server, int port, int type);

apps/s_cb.c

@@ -285,20 +285,33 @@ int set_cert_key_stuff(SSL_CTX *ctx, X509 *cert, EVP_PKEY *key,
 	return 1;
 	}
 
-int ssl_print_sigalgs(BIO *out, SSL *s)
+static int do_print_sigalgs(BIO *out, SSL *s, int client, int shared)
 	{
 	int i, nsig;
-	nsig = SSL_get_sigalgs(s, -1, NULL, NULL, NULL, NULL, NULL);
+	if (shared)
+		nsig = SSL_get_shared_sigalgs(s, -1, NULL, NULL, NULL,
+							NULL, NULL);
+	else
+		nsig = SSL_get_sigalgs(s, -1, NULL, NULL, NULL, NULL, NULL);
 	if (nsig == 0)
 		return 1;
 
+	if (shared)
+		BIO_puts(out, "Shared ");
+
+	if (client)
+		BIO_puts(out, "Requested ");
 	BIO_puts(out, "Signature Algorithms: ");
 	for (i = 0; i < nsig; i++)
 		{
 		int hash_nid, sign_nid;
 		unsigned char rhash, rsign;
 		const char *sstr = NULL;
-		SSL_get_sigalgs(s, i, &sign_nid, &hash_nid, NULL,
+		if (shared)
+			SSL_get_shared_sigalgs(s, i, &sign_nid, &hash_nid, NULL,
+							&rsign, &rhash);
+		else
+			SSL_get_sigalgs(s, i, &sign_nid, &hash_nid, NULL,
 							&rsign, &rhash);
 		if (i)
 			BIO_puts(out, ":");
@@ -321,6 +334,13 @@ int ssl_print_sigalgs(BIO *out, SSL *s)
 	return 1;
 	}
 
+int ssl_print_sigalgs(BIO *out, SSL *s, int client)
+	{
+	do_print_sigalgs(out, s, client, 0);
+	do_print_sigalgs(out, s, client, 1);
+	return 1;
+	}
+
 int ssl_print_curves(BIO *out, SSL *s)
 	{
 	int i, ncurves, *curves, nid;

apps/s_client.c

@@ -2049,7 +2049,7 @@ static void print_stuff(BIO *bio, SSL *s, int full)
 			BIO_write(bio,"\n",1);
 			}
 
-		ssl_print_sigalgs(bio, s);
+		ssl_print_sigalgs(bio, s, 1);
 
 		BIO_printf(bio,"---\nSSL handshake has read %ld bytes and written %ld bytes\n",
 			BIO_number_read(SSL_get_rbio(s)),

apps/s_server.c

@@ -2536,7 +2536,7 @@ static int init_ssl_connection(SSL *con)
 	if (SSL_get_shared_ciphers(con,buf,sizeof buf) != NULL)
 		BIO_printf(bio_s_out,"Shared ciphers:%s\n",buf);
 	str=SSL_CIPHER_get_name(SSL_get_current_cipher(con));
-	ssl_print_sigalgs(bio_s_out, con);
+	ssl_print_sigalgs(bio_s_out, con, 0);
 	ssl_print_curves(bio_s_out, con);
 	BIO_printf(bio_s_out,"CIPHER is %s\n",(str != NULL)?str:"(NONE)");
 
@@ -2851,7 +2851,7 @@ static int www_body(char *hostname, int s, unsigned char *context)
 					}
 				BIO_puts(io,"\n");
 				}
-			ssl_print_sigalgs(io, con);
+			ssl_print_sigalgs(io, con, 0);
 			ssl_print_curves(io, con);
 			BIO_printf(io,(SSL_cache_hit(con)
 				?"---\nReused, "

ssl/ssl.h

@@ -2532,6 +2532,7 @@ void ERR_load_SSL_strings(void);
 #define SSL_R_NO_RENEGOTIATION				 339
 #define SSL_R_NO_REQUIRED_DIGEST			 324
 #define SSL_R_NO_SHARED_CIPHER				 193
+#define SSL_R_NO_SHARED_SIGATURE_ALGORITHMS		 376
 #define SSL_R_NO_SRTP_PROFILES				 359
 #define SSL_R_NO_VERIFY_CALLBACK			 194
 #define SSL_R_NULL_SSL_CTX				 195

ssl/ssl_cert.c

@@ -160,7 +160,7 @@ int SSL_get_ex_data_X509_STORE_CTX_idx(void)
 	return ssl_x509_store_ctx_idx;
 	}
 
-static void ssl_cert_set_default_md(CERT *cert)
+void ssl_cert_set_default_md(CERT *cert)
 	{
 	/* Set digest values to defaults */
 #ifndef OPENSSL_NO_DSA
@@ -373,6 +373,8 @@ CERT *ssl_cert_dup(CERT *cert)
 		}
 	else
 		ret->conf_sigalgs = NULL;
+	/* Shared sigalgs also NULL */
+	ret->shared_sigalgs = NULL;
 
 	return(ret);
 
@@ -464,6 +466,8 @@ void ssl_cert_free(CERT *c)
 		OPENSSL_free(c->peer_sigalgs);
 	if (c->conf_sigalgs)
 		OPENSSL_free(c->conf_sigalgs);
+	if (c->shared_sigalgs)
+		OPENSSL_free(c->shared_sigalgs);
 	OPENSSL_free(c);
 	}
 

ssl/ssl_err.c

@@ -463,6 +463,7 @@ static ERR_STRING_DATA SSL_str_reasons[]=
 {ERR_REASON(SSL_R_NO_RENEGOTIATION)      ,"no renegotiation"},
 {ERR_REASON(SSL_R_NO_REQUIRED_DIGEST)    ,"digest requred for handshake isn't computed"},
 {ERR_REASON(SSL_R_NO_SHARED_CIPHER)      ,"no shared cipher"},
+{ERR_REASON(SSL_R_NO_SHARED_SIGATURE_ALGORITHMS),"no shared sigature algorithms"},
 {ERR_REASON(SSL_R_NO_SRTP_PROFILES)      ,"no srtp profiles"},
 {ERR_REASON(SSL_R_NO_VERIFY_CALLBACK)    ,"no verify callback"},
 {ERR_REASON(SSL_R_NULL_SSL_CTX)          ,"null ssl ctx"},

ssl/ssl_locl.h

@@ -523,15 +523,20 @@ typedef struct cert_st
 	 * algorithms extension for server or as part of a certificate
 	 * request for client.
 	 */
-	TLS_SIGALGS *peer_sigalgs;
+	unsigned char *peer_sigalgs;
 	/* Size of above array */
 	size_t peer_sigalgslen;
 	/* configured signature algorithms (can be NULL for default).
 	 * sent in signature algorithms extension or certificate request.
 	 */
-	TLS_SIGALGS *conf_sigalgs;
+	unsigned char *conf_sigalgs;
 	/* Size of above array */
 	size_t conf_sigalgslen;
+	/* Signature algorithms shared by client and server: cached
+	 * because these are used most often
+	 */
+	TLS_SIGALGS *shared_sigalgs;
+	size_t shared_sigalgslen;
 
 	int references; /* >1 only if SSL_copy_session_id is used */
 	} CERT;
@@ -841,6 +846,7 @@ void ssl_clear_cipher_ctx(SSL *s);
 int ssl_clear_bad_session(SSL *s);
 CERT *ssl_cert_new(void);
 CERT *ssl_cert_dup(CERT *cert);
+void ssl_cert_set_default_md(CERT *cert);
 int ssl_cert_inst(CERT **o);
 void ssl_cert_clear_certs(CERT *c);
 void ssl_cert_free(CERT *c);