Generate our ssl session certs with a plausible lifetime

Nobody but Tor uses certs on the wire with 2 hour lifetimes,
and it makes us stand out. Resolves ticket 4014.

changes/bug4014

@@ -0,0 +1,3 @@
+  o Minor features:
+    - Adjust the expiration time on our SSL session certificates to
+      better match SSL certs seen in the wild. Resolves ticket 4014.

src/or/main.c

@@ -866,12 +866,14 @@ run_scheduled_events(time_t now)
       now + DESCRIPTOR_FAILURE_RESET_INTERVAL;
   }
 
-  /** 1b. Every MAX_SSL_KEY_LIFETIME seconds, we change our TLS context. */
+  /** 1b. Every MAX_SSL_KEY_LIFETIME_INTERNAL seconds, we change our
+   * TLS context. */
   if (!last_rotated_x509_certificate)
     last_rotated_x509_certificate = now;
-  if (last_rotated_x509_certificate+MAX_SSL_KEY_LIFETIME < now) {
+  if (last_rotated_x509_certificate+MAX_SSL_KEY_LIFETIME_INTERNAL < now) {
     log_info(LD_GENERAL,"Rotating tls context.");
-    if (tor_tls_context_new(get_identity_key(), MAX_SSL_KEY_LIFETIME) < 0) {
+    if (tor_tls_context_new(get_identity_key(),
+                            MAX_SSL_KEY_LIFETIME_ADVERTISED) < 0) {
       log_warn(LD_BUG, "Error reinitializing TLS context");
       /* XXX is it a bug here, that we just keep going? -RD */
     }

src/or/or.h

@@ -166,7 +166,9 @@
 /** How often do we rotate onion keys? */
 #define MIN_ONION_KEY_LIFETIME (7*24*60*60)
 /** How often do we rotate TLS contexts? */
-#define MAX_SSL_KEY_LIFETIME (2*60*60)
+#define MAX_SSL_KEY_LIFETIME_INTERNAL (2*60*60)
+/** What expiry time shall we place on our SSL certs? */
+#define MAX_SSL_KEY_LIFETIME_ADVERTISED (365*24*60*60)
 
 /** How old do we allow a router to get before removing it
  * from the router list? In seconds. */

src/or/router.c

@@ -458,7 +458,8 @@ init_keys(void)
     }
     set_identity_key(prkey);
     /* Create a TLS context; default the client nickname to "client". */
-    if (tor_tls_context_new(get_identity_key(), MAX_SSL_KEY_LIFETIME) < 0) {
+    if (tor_tls_context_new(get_identity_key(),
+                            MAX_SSL_KEY_LIFETIME_ADVERTISED) < 0) {
       log_err(LD_GENERAL,"Error creating TLS context for Tor client.");
       return -1;
     }
@@ -536,7 +537,8 @@ init_keys(void)
   tor_free(keydir);
 
   /* 3. Initialize link key and TLS context. */
-  if (tor_tls_context_new(get_identity_key(), MAX_SSL_KEY_LIFETIME) < 0) {
+  if (tor_tls_context_new(get_identity_key(),
+                          MAX_SSL_KEY_LIFETIME_ADVERTISED) < 0) {
     log_err(LD_GENERAL,"Error initializing TLS context");
     return -1;
   }