Added the PFS priority string option.

3 files changed, 39 insertions, 0 deletions

diff --git a/NEWS b/NEWS
index 2719bda8f2..c8369b9253 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,8 @@ See the end for copying conditions.
 
 * Version 3.1.14 (unreleased)
 
+** libgnutls: Added the PFS priority string option.
+
 ** libgnutls: Fixes in gnutls_record_send_range(). Report and initial fix by 
 Alfredo Pironti.
 
diff --git a/doc/cha-gtls-app.texi b/doc/cha-gtls-app.texi
index 9d30160299..d32e0f41bd 100644
--- a/doc/cha-gtls-app.texi
+++ b/doc/cha-gtls-app.texi
@@ -873,6 +873,13 @@ Means all the known to be secure ciphersuites. The ciphers are sorted by securit
 margin, although the 256-bit ciphers are included as a fallback only.
 The message authenticity security level is of 64 bits or more.
 
+@item PFS @tab
+Means all the known to be secure ciphersuites that support perfect forward
+secrecy. The ciphers are sorted by security
+margin, although the 256-bit ciphers are included as a fallback only.
+The message authenticity security level is of 64 bits or more. This
+option is available since 3.2.4 or later.
+
 @item SECURE128 @tab
 Means all known to be secure ciphersuites that offer a 
 security level 128-bit or more and a message authenticity
diff --git a/lib/gnutls_priority.c b/lib/gnutls_priority.c
index 369ef4b623..0630a46a05 100644
--- a/lib/gnutls_priority.c
+++ b/lib/gnutls_priority.c
@@ -309,6 +309,18 @@ static const int kx_priority_performance[] = {
   0
 };
 
+static const int kx_priority_pfs[] = {
+#ifdef ENABLE_ECDHE
+  GNUTLS_KX_ECDHE_ECDSA,
+  GNUTLS_KX_ECDHE_RSA,
+#endif
+#ifdef ENABLE_DHE
+  GNUTLS_KX_DHE_RSA,
+  GNUTLS_KX_DHE_DSS,
+#endif
+  0
+};
+
 static const int kx_priority_suiteb[] = {
   GNUTLS_KX_ECDHE_ECDSA,
   0
@@ -641,6 +653,7 @@ gnutls_priority_set (gnutls_session_t session, gnutls_priority_t priority)
 
 #define LEVEL_NONE "NONE"
 #define LEVEL_NORMAL "NORMAL"
+#define LEVEL_PFS "PFS"
 #define LEVEL_PERFORMANCE "PERFORMANCE"
 #define LEVEL_SECURE128 "SECURE128"
 #define LEVEL_SECURE192 "SECURE192"
@@ -684,6 +697,19 @@ bulk_rmadd_func *func;
         priority_cache->level = GNUTLS_SEC_PARAM_VERY_WEAK;
       return 1;
     }
+  else if (strcasecmp (level, LEVEL_PFS) == 0)
+    {
+      func (&priority_cache->cipher, cipher_priority_normal);
+      func (&priority_cache->kx, kx_priority_pfs);
+      func (&priority_cache->mac, mac_priority_normal);
+      func (&priority_cache->sign_algo,
+                     sign_priority_default);
+      func (&priority_cache->supported_ecc, supported_ecc_normal);
+
+      if (priority_cache->level == 0)
+        priority_cache->level = GNUTLS_SEC_PARAM_VERY_WEAK;
+      return 1;
+    }
   else if (strcasecmp (level, LEVEL_SECURE256) == 0
            || strcasecmp (level, LEVEL_SECURE192) == 0)
     {
@@ -784,6 +810,10 @@ bulk_rmadd_func *func;
  * included as a fallback only.  The ciphers are sorted by security
  * margin.
  *
+ * "PFS" means all "secure" ciphersuites that support perfect forward secrecy. 
+ * The 256-bit ciphers are included as a fallback only.  
+ * The ciphers are sorted by security margin.
+ *
  * "SECURE128" means all "secure" ciphersuites of security level 128-bit
  * or more.
  *