AST-2016-001 http: Provide greater control of TLS and set modern defaults.

This change exposes the configuration of various aspects of the TLS
support and sets the default to the modern standards.

The TLS cipher is now set to the best values according to the
Mozilla OpSec team, different TLS versions can now be disabled, and
the cipher order can be forced to be that of the server instead of
the client.

ASTERISK-24972 #close

Change-Id: I0a10f2883f7559af5e48dee0901251dbf30d45b8

4 files changed, 59 insertions, 8 deletions

diff --git a/configs/samples/http.conf.sample b/configs/samples/http.conf.sample
index 1d23a67f6..342dff483 100644
--- a/configs/samples/http.conf.sample
+++ b/configs/samples/http.conf.sample
@@ -90,6 +90,26 @@ bindaddr=127.0.0.1
 ; private in same .pem file.
 ; openssl req -new -x509 -days 365 -nodes -out /tmp/foo.pem -keyout /tmp/foo.pem
 ;
+; tlscipher=                             ; The list of allowed ciphers
+;                                        ; if none are specified the following cipher
+;                                        ; list will be used instead:
+; ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:
+; ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:
+; kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:
+; ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:
+; ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:
+; DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:
+; AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:
+; AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:
+; !EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA
+;
+; tlsdisablev1=yes                ; Disable TLSv1 support - if not set this defaults to "yes"
+; tlsdisablev11=yes               ; Disable TLSv1.1 support - if not set this defaults to "no"
+; tlsdisablev12=yes               ; Disable TLSv1.2 support - if not set this defaults to "no"
+;
+; tlsservercipherorder=yes        ; Use the server preference order instead of the client order
+;                                 ; Defaults to "yes"
+;
 ; The post_mappings section maps URLs to real paths on the filesystem.  If a
 ; POST is done from within an authenticated manager session to one of the
 ; configured POST mappings, then any files in the POST will be placed in the
diff --git a/include/asterisk/tcptls.h b/include/asterisk/tcptls.h
index 0e8d9d042..e1a632cca 100644
--- a/include/asterisk/tcptls.h
+++ b/include/asterisk/tcptls.h
@@ -86,7 +86,15 @@ enum ast_ssl_flags {
 	/*! Use SSLv3 for outgoing client connections */
 	AST_SSL_SSLV3_CLIENT = (1 << 4),
 	/*! Use TLSv1 for outgoing client connections */
-	AST_SSL_TLSV1_CLIENT = (1 << 5)
+	AST_SSL_TLSV1_CLIENT = (1 << 5),
+	/*! Use server cipher order instead of the client order */
+	AST_SSL_SERVER_CIPHER_ORDER = (1 << 6),
+	/*! Disable TLSv1 support */
+	AST_SSL_DISABLE_TLSV1 = (1 << 7),
+	/*! Disable TLSv1.1 support */
+	AST_SSL_DISABLE_TLSV11 = (1 << 8),
+	/*! Disable TLSv1.2 support */
+	AST_SSL_DISABLE_TLSV12 = (1 << 9),
 };
 
 struct ast_tls_config {
diff --git a/main/http.c b/main/http.c
index 26e218ba0..c343cb236 100644
--- a/main/http.c
+++ b/main/http.c
@@ -2102,10 +2102,13 @@ static int __ast_http_load(int reload)
 	}
 	http_tls_cfg.pvtfile = ast_strdup("");
 
+	/* Apply modern intermediate settings according to the Mozilla OpSec team as of July 30th, 2015 but disable TLSv1 */
+	ast_set_flag(&http_tls_cfg.flags, AST_SSL_DISABLE_TLSV1 | AST_SSL_SERVER_CIPHER_ORDER);
+
 	if (http_tls_cfg.cipher) {
 		ast_free(http_tls_cfg.cipher);
 	}
-	http_tls_cfg.cipher = ast_strdup("");
+	http_tls_cfg.cipher = ast_strdup("ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-DSS-AES128-GCM-SHA256:kEDH+AESGCM:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES256-SHA:ECDHE-ECDSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-DSS-AES128-SHA256:DHE-RSA-AES256-SHA256:DHE-DSS-AES256-SHA:DHE-RSA-AES256-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:AES:CAMELLIA:DES-CBC3-SHA:!aNULL:!eNULL:!EXPORT:!DES:!RC4:!MD5:!PSK:!aECDH:!EDH-DSS-DES-CBC3-SHA:!EDH-RSA-DES-CBC3-SHA:!KRB5-DES-CBC3-SHA");
 
 	AST_RWLIST_WRLOCK(&uri_redirects);
 	while ((redirect = AST_RWLIST_REMOVE_HEAD(&uri_redirects, entry))) {
@@ -2131,8 +2134,6 @@ static int __ast_http_load(int reload)
 			&& strcasecmp(v->name, "tlsdontverifyserver")
 			&& strcasecmp(v->name, "tlsclientmethod")
 			&& strcasecmp(v->name, "sslclientmethod")
-			&& strcasecmp(v->name, "tlscipher")
-			&& strcasecmp(v->name, "sslcipher")
 			&& !ast_tls_read_conf(&http_tls_cfg, &https_desc, v->name, v->value)) {
 			continue;
 		}
diff --git a/main/tcptls.c b/main/tcptls.c
index 1b0c26ad2..6f37724d9 100644
--- a/main/tcptls.c
+++ b/main/tcptls.c
@@ -759,7 +759,8 @@ static int __ssl_setup(struct ast_tls_config *cfg, int client)
 	return 0;
 #else
 	int disable_ssl = 0;
- 
+	long ssl_opts = 0;
+
 	if (!cfg->enabled) {
 		return 0;
 	}
@@ -807,11 +808,24 @@ static int __ssl_setup(struct ast_tls_config *cfg, int client)
 	 * them. SSLv23_*_method supports TLSv1+.
 	 */
 	if (disable_ssl) {
-		long ssl_opts;
+		ssl_opts |= SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3;
+	}
+
+	if (ast_test_flag(&cfg->flags, AST_SSL_SERVER_CIPHER_ORDER)) {
+		ssl_opts |= SSL_OP_CIPHER_SERVER_PREFERENCE;
+	}
 
-		ssl_opts = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3;
-		SSL_CTX_set_options(cfg->ssl_ctx, ssl_opts);
+	if (ast_test_flag(&cfg->flags, AST_SSL_DISABLE_TLSV1)) {
+		ssl_opts |= SSL_OP_NO_TLSv1;
 	}
+	if (ast_test_flag(&cfg->flags, AST_SSL_DISABLE_TLSV11)) {
+		ssl_opts |= SSL_OP_NO_TLSv1_1;
+	}
+	if (ast_test_flag(&cfg->flags, AST_SSL_DISABLE_TLSV12)) {
+		ssl_opts |= SSL_OP_NO_TLSv1_2;
+	}
+
+	SSL_CTX_set_options(cfg->ssl_ctx, ssl_opts);
 
 	SSL_CTX_set_verify(cfg->ssl_ctx,
 		ast_test_flag(&cfg->flags, AST_SSL_VERIFY_CLIENT) ? SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT : SSL_VERIFY_NONE,
@@ -1164,6 +1178,14 @@ int ast_tls_read_conf(struct ast_tls_config *tls_cfg, struct ast_tcptls_session_
 			ast_clear_flag(&tls_cfg->flags, AST_SSL_TLSV1_CLIENT);
 			ast_clear_flag(&tls_cfg->flags, AST_SSL_SSLV3_CLIENT);
 		}
+	} else if (!strcasecmp(varname, "tlsservercipherorder")) {
+		ast_set2_flag(&tls_cfg->flags, ast_true(value), AST_SSL_SERVER_CIPHER_ORDER);
+	} else if (!strcasecmp(varname, "tlsdisablev1")) {
+		ast_set2_flag(&tls_cfg->flags, ast_true(value), AST_SSL_DISABLE_TLSV1);
+	} else if (!strcasecmp(varname, "tlsdisablev11")) {
+		ast_set2_flag(&tls_cfg->flags, ast_true(value), AST_SSL_DISABLE_TLSV11);
+	} else if (!strcasecmp(varname, "tlsdisablev12")) {
+		ast_set2_flag(&tls_cfg->flags, ast_true(value), AST_SSL_DISABLE_TLSV12);
 	} else {
 		return -1;
 	}