Print warnings if old daemon versions are used.

* common/status.h (STATUS_WARNING): New.
* g10/call-agent.c (warn_version_mismatch): New.
(start_agent): Call warn function.
* g10/call-dirmngr.c: Include status.h.
(warn_version_mismatch): New.
(create_context): Call warn function.
* sm/call-agent.c (warn_version_mismatch): New.
(start_agent): Call warn function.
(gpgsm_agent_learn): Call warn function.
* sm/call-dirmngr.c (warn_version_mismatch): New.
(prepare_dirmngr): Call warn function.
--

We have seen too often bug reports which are due to still running old
versions of the daemons.  To catch this problematic use we now print
warning messages and also provide the warning via the status
interface.

Signed-off-by: Werner Koch <wk@gnupg.org>

1 files changed, 42 insertions, 4 deletions

diff --git a/g10/call-agent.c b/g10/call-agent.c
index 3600579bd..83fabcc32 100644
--- a/g10/call-agent.c
+++ b/g10/call-agent.c
@@ -253,6 +253,40 @@ check_hijacking (assuan_context_t ctx)
 
 
 
+/* Print a warning if the server's version number is less than our
+   version number.  Returns an error code on a connection problem.  */
+static gpg_error_t
+warn_version_mismatch (assuan_context_t ctx, const char *servername, int mode)
+{
+  gpg_error_t err;
+  char *serverversion;
+  const char *myversion = strusage (13);
+
+  err = get_assuan_server_version (ctx, mode, &serverversion);
+  if (err)
+    log_error (_("error getting version from '%s': %s\n"),
+               servername, gpg_strerror (err));
+  else if (!compare_version_strings (serverversion, myversion))
+    {
+      char *warn;
+
+      warn = xtryasprintf (_("server '%s' is older than us (%s < %s)"),
+                           servername, serverversion, myversion);
+      if (!warn)
+        err = gpg_error_from_syserror ();
+      else
+        {
+          log_info (_("WARNING: %s\n"), warn);
+          write_status_strings (STATUS_WARNING, "server_version_mismatch 0",
+                                " ", warn, NULL);
+          xfree (warn);
+        }
+    }
+  xfree (serverversion);
+  return err;
+}
+
+
 /* Try to connect to the agent via socket or fork it off and work by
    pipes.  Handle the server's initial greeting */
 static int
@@ -286,7 +320,8 @@ start_agent (ctrl_t ctrl, int for_card)
               log_info (_("no gpg-agent running in this session\n"));
             }
         }
-      else if (!rc)
+      else if (!rc
+               && !(rc = warn_version_mismatch (agent_ctx, GPG_AGENT_NAME, 0)))
         {
           /* Tell the agent that we support Pinentry notifications.
              No error checking so that it will work also with older
@@ -324,9 +359,12 @@ start_agent (ctrl_t ctrl, int for_card)
       struct agent_card_info_s info;
 
       memset (&info, 0, sizeof info);
-      rc = assuan_transact (agent_ctx, "SCD SERIALNO openpgp",
-                            NULL, NULL, NULL, NULL,
-                            learn_status_cb, &info);
+
+      rc = warn_version_mismatch (agent_ctx, SCDAEMON_NAME, 2);
+      if (!rc)
+        rc = assuan_transact (agent_ctx, "SCD SERIALNO openpgp",
+                              NULL, NULL, NULL, NULL,
+                              learn_status_cb, &info);
       if (rc)
         {
           switch (gpg_err_code (rc))