add support for (disabling) TLS v1.1 and v1.2

src/drv_imap.c

@@ -1980,6 +1980,10 @@ imap_parse_store( conffile_t *cfg, store_conf_t **storep )
 			server->sconf.use_sslv3 = parse_bool( cfg );
 		else if (!strcasecmp( "UseTLSv1", cfg->cmd ))
 			server->sconf.use_tlsv1 = parse_bool( cfg );
+		else if (!strcasecmp( "UseTLSv1.1", cfg->cmd ))
+			server->sconf.use_tlsv11 = parse_bool( cfg );
+		else if (!strcasecmp( "UseTLSv1.2", cfg->cmd ))
+			server->sconf.use_tlsv12 = parse_bool( cfg );
 		else if (!strcasecmp( "RequireCRAM", cfg->cmd ))
 			server->require_cram = parse_bool( cfg );
 #endif

src/isync.h

@@ -63,6 +63,8 @@ typedef struct server_conf {
 	unsigned use_sslv2:1;
 	unsigned use_sslv3:1;
 	unsigned use_tlsv1:1;
+	unsigned use_tlsv11:1;
+	unsigned use_tlsv12:1;
 
 	/* these are actually variables and are leaked at the end */
 	SSL_CTX *SSLContext;

src/mbsync.1

@@ -294,6 +294,16 @@ Use TLSv1 for communication with the IMAP server over SSL?
 (Default: \fIyes\fR)
 ..
 .TP
+\fBUseTLSv1.1\fR \fIyes\fR|\fIno\fR
+Use TLSv1.1 for communication with the IMAP server over SSL?
+(Default: \fIno\fR)
+..
+.TP
+\fBUseTLSv1.2\fR \fIyes\fR|\fIno\fR
+Use TLSv1.2 for communication with the IMAP server over SSL?
+(Default: \fIno\fR)
+..
+.TP
 \fBPipelineDepth\fR \fIdepth\fR
 Maximum number of IMAP commands which can be simultaneously in flight.
 Setting this to \fI1\fR disables pipelining.

src/socket.c

@@ -231,14 +231,9 @@ static int
 init_ssl_ctx( const server_conf_t *conf )
 {
 	server_conf_t *mconf = (server_conf_t *)conf;
-	const SSL_METHOD *method;
 	int options = 0;
 
-	if (conf->use_tlsv1 && !conf->use_sslv2 && !conf->use_sslv3)
-		method = TLSv1_client_method();
-	else
-		method = SSLv23_client_method();
-	mconf->SSLContext = SSL_CTX_new( method );
+	mconf->SSLContext = SSL_CTX_new( SSLv23_client_method() );
 
 	if (!conf->use_sslv2)
 		options |= SSL_OP_NO_SSLv2;
@@ -246,6 +241,14 @@ init_ssl_ctx( const server_conf_t *conf )
 		options |= SSL_OP_NO_SSLv3;
 	if (!conf->use_tlsv1)
 		options |= SSL_OP_NO_TLSv1;
+#ifdef SSL_OP_NO_TLSv1_1
+	if (!conf->use_tlsv11)
+		options |= SSL_OP_NO_TLSv1_1;
+#endif
+#ifdef SSL_OP_NO_TLSv1_2
+	if (!conf->use_tlsv12)
+		options |= SSL_OP_NO_TLSv1_2;
+#endif
 
 	SSL_CTX_set_options( mconf->SSLContext, options );