[Camel] Disable SSL v2 and weak ciphers by default

The change for disabled weak ciphers require at least NSS 3.14, thus
weak ciphers are enabled, if it's compiled with older NSS. In case
any server will require either weak ciphers or SSL v2 (while there
really should not anyone use it these days), then two environment
variables were added:

   CAMEL_SSL_V2_ENABLE=1 - to have SSL v2 enabled, otherwise it's disabled,
       regardless what camel providers request (they usually request v2 and
       v3 together)

   CAMEL_SSL_WEAK_CIPHERS=1 - to enable weak ciphers, almost the same as
       before; otherwise these are disabled and only those covered by
       NSS_SetDomesticPolicy() are enabled

These are added to the group of one for SSL V2 compatible hello:

   CAMEL_SSL_V2_HELLO=1 - to force SSL v2 compatible hello on SSL connections

diff --git a/camel/camel-tcp-stream-ssl.c b/camel/camel-tcp-stream-ssl.c
index 9e58400..97f053c 100644 (file)
--- a/camel/camel-tcp-stream-ssl.c
+++ b/camel/camel-tcp-stream-ssl.c
@@ -544,6 +544,7 @@ enable_ssl (CamelTcpStreamSSL *ssl,
             PRFileDesc *fd)
 {
        PRFileDesc *ssl_fd;
+       static gchar v2_enabled = -1;
 
        g_assert (fd != NULL);
 
@@ -553,7 +554,11 @@ enable_ssl (CamelTcpStreamSSL *ssl,
 
        SSL_OptionSet (ssl_fd, SSL_SECURITY, PR_TRUE);
 
-       if (ssl->priv->flags & CAMEL_TCP_STREAM_SSL_ENABLE_SSL2) {
+       /* check camel.c for the same "CAMEL_SSL_V2_ENABLE" */
+       if (v2_enabled == -1)
+               v2_enabled = g_strcmp0 (g_getenv ("CAMEL_SSL_V2_ENABLE"), "1") == 0 ? 1 : 0;
+
+       if (v2_enabled && (ssl->priv->flags & CAMEL_TCP_STREAM_SSL_ENABLE_SSL2) != 0) {
                static gchar v2_hello = -1;
 
                /* Zarafa server with disabled SSL v2 rejects connection when

diff --git a/camel/camel.c b/camel/camel.c
index 49f2d60..fc73fe5 100644 (file)
--- a/camel/camel.c
+++ b/camel/camel.c
@@ -31,6 +31,7 @@
 #include <prthread.h>
 #include "nss.h"      /* Don't use <> here or it will include the system nss.h instead */
 #include <ssl.h>
+#include <sslproto.h>
 #include <errno.h>
 
 #include <glib/gi18n-lib.h>
@@ -95,10 +96,22 @@ camel_init (const gchar *configdir,
        camel_debug_init ();
 
        if (nss_init) {
+               static gchar v2_enabled = -1, weak_ciphers = -1;
                gchar *nss_configdir = NULL;
                gchar *nss_sql_configdir = NULL;
                SECStatus status = SECFailure;
-               PRUint16 indx;
+
+#if NSS_VMAJOR < 3 || (NSS_VMAJOR == 3 && NSS_VMINOR < 14)
+               /* NSS pre-3.14 has most of the ciphers disabled, thus enable
+                * weak ciphers, if it's compiled against such */
+               weak_ciphers = 1;
+#endif
+
+               /* check camel-tcp-stream-ssl.c for the same "CAMEL_SSL_V2_ENABLE" */
+               if (v2_enabled == -1)
+                       v2_enabled = g_strcmp0 (g_getenv ("CAMEL_SSL_V2_ENABLE"), "1") == 0 ? 1 : 0;
+               if (weak_ciphers == -1)
+                       weak_ciphers = g_strcmp0 (g_getenv ("CAMEL_SSL_WEAK_CIPHERS"), "1") == 0 ? 1 : 0;
 
                if (nss_initlock == NULL) {
                        PR_Init (PR_SYSTEM_THREAD, PR_PRIORITY_NORMAL, 10);
@@ -185,18 +198,24 @@ skip_nss_init:
 
                NSS_SetDomesticPolicy ();
 
-               PR_Unlock (nss_initlock);
+               if (weak_ciphers) {
+                       PRUint16 indx;
 
-               /* we must enable all ciphersuites */
-               for (indx = 0; indx < SSL_NumImplementedCiphers; indx++) {
-                       if (!SSL_IS_SSL2_CIPHER (SSL_ImplementedCiphers[indx]))
-                               SSL_CipherPrefSetDefault (SSL_ImplementedCiphers[indx], PR_TRUE);
+                       /* enable SSL3/TLS cipher-suites */
+                       for (indx = 0; indx < SSL_NumImplementedCiphers; indx++) {
+                               if (!SSL_IS_SSL2_CIPHER (SSL_ImplementedCiphers[indx]) &&
+                                   SSL_ImplementedCiphers[indx] != SSL_RSA_WITH_NULL_SHA &&
+                                   SSL_ImplementedCiphers[indx] != SSL_RSA_WITH_NULL_MD5)
+                                       SSL_CipherPrefSetDefault (SSL_ImplementedCiphers[indx], PR_TRUE);
+                       }
                }
 
-               SSL_OptionSetDefault (SSL_ENABLE_SSL2, PR_TRUE);
+               SSL_OptionSetDefault (SSL_ENABLE_SSL2, v2_enabled ? PR_TRUE : PR_FALSE);
+               SSL_OptionSetDefault (SSL_V2_COMPATIBLE_HELLO, PR_FALSE);
                SSL_OptionSetDefault (SSL_ENABLE_SSL3, PR_TRUE);
                SSL_OptionSetDefault (SSL_ENABLE_TLS, PR_TRUE);
-               SSL_OptionSetDefault (SSL_V2_COMPATIBLE_HELLO, PR_TRUE /* maybe? */);
+
+               PR_Unlock (nss_initlock);
 
                g_free (nss_configdir);
                g_free (nss_sql_configdir);