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>

common/status.h

@@ -141,6 +141,7 @@ enum
     STATUS_PLAINTEXT_FOLLOWS,   /* Used by g13-syshelp  */
 
     STATUS_ERROR,
+    STATUS_WARNING,
     STATUS_SUCCESS,
     STATUS_FAILURE,
 

doc/DETAILS

@@ -840,7 +840,12 @@ pkd:0:1024:B665B1435F4C2 .... FF26ABB:
     should not contain spaces.  The error code is a either a string
     commencing with a letter or such a string prefixed with a
     numerical error code and an underscore; e.g.: "151011327_EOF".
-
+*** WARNING <location> <error code> [<text>]
+    This is a generic warning status message, it might be followed by
+    error location specific data. <error code> and <location>
+    should not contain spaces.  The error code is a either a string
+    commencing with a letter or such a string prefixed with a
+    numerical error code and an underscore; e.g.: "151011327_EOF".
 *** SUCCESS [<location>]
     Postive confirmation that an operation succeeded.  It is used
     similar to ISO-C's EXIT_SUCCESS.  <location> is optional but if

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
@@ -324,6 +359,9 @@ start_agent (ctrl_t ctrl, int for_card)
       struct agent_card_info_s info;
 
       memset (&info, 0, sizeof 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);

g10/call-dirmngr.c

@@ -38,6 +38,7 @@
 #include "i18n.h"
 #include "asshelp.h"
 #include "keyserver.h"
+#include "status.h"
 #include "call-dirmngr.h"
 
 
@@ -132,6 +133,40 @@ gpg_dirmngr_deinit_session_data (ctrl_t ctrl)
 }
 
 
+/* 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)
+{
+  gpg_error_t err;
+  char *serverversion;
+  const char *myversion = strusage (13);
+
+  err = get_assuan_server_version (ctx, 0, &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 Dirmngr via a socket or spawn it if possible.
    Handle the server's initial greeting and set global options.  */
 static gpg_error_t
@@ -157,7 +192,7 @@ create_context (ctrl_t ctrl, assuan_context_t *r_ctx)
           log_info (_("no dirmngr running in this session\n"));
         }
     }
-  else if (!err)
+  else if (!err && !(err = warn_version_mismatch (ctx, DIRMNGR_NAME)))
     {
       char *line;
 

sm/call-agent.c

@@ -76,6 +76,41 @@ struct import_key_parm_s
 
 
 
+/* 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 (ctrl_t ctrl, 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);
+          gpgsm_status2 (ctrl, 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
@@ -108,7 +143,8 @@ start_agent (ctrl_t ctrl)
               log_info (_("no gpg-agent running in this session\n"));
             }
         }
-      else if (!rc)
+      else if (!rc && !(rc = warn_version_mismatch (ctrl, 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
@@ -919,6 +955,10 @@ gpgsm_agent_learn (ctrl_t ctrl)
   if (rc)
     return rc;
 
+  rc = warn_version_mismatch (ctrl, agent_ctx, SCDAEMON_NAME, 2);
+  if (rc)
+    return rc;
+
   init_membuf (&data, 4096);
   learn_parm.error = 0;
   learn_parm.ctrl = ctrl;

sm/call-dirmngr.c

@@ -149,6 +149,41 @@ get_membuf (struct membuf *mb, size_t *len)
 }
 
 
+/* 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 (ctrl_t ctrl, 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);
+          gpgsm_status2 (ctrl, STATUS_WARNING, "server_version_mismatch 0",
+                         warn, NULL);
+          xfree (warn);
+        }
+    }
+  xfree (serverversion);
+  return err;
+}
+
+
 /* This function prepares the dirmngr for a new session.  The
    audit-events option is used so that other dirmngr clients won't get
    disturbed by such events.  */
@@ -157,6 +192,9 @@ prepare_dirmngr (ctrl_t ctrl, assuan_context_t ctx, gpg_error_t err)
 {
   struct keyserver_spec *server;
 
+  if (!err)
+    err = warn_version_mismatch (ctrl, ctx, DIRMNGR_NAME, 0);
+
   if (!err)
     {
       err = assuan_transact (ctx, "OPTION audit-events=1",