exactness: handbuild a new argv array instead of reassemling the new one

this commit removes the code that was changing argv values, and replaces
it with a new array. Which is absolutly fine, as the argv / argc values
are never accessed later on. Only the copies that have been passed to
efl_main or elm_main.

This resolves several issues:
1. the for loop is useless, every single array element that gets
   initialized with it, is some offset from argv[0] this may also crash
   when argv[i] - argv[opt_args] is bigger strlen argv[0].
2. The memcpy here is super dangerous, the dest array is not garanteed
   to have the same size as argv[0], this only works if the client
   application name is shorter than the name "exactness_recorder"
3. The memset here is absolutly wrong. There is again no garantee that
   the array has the expected size behind that, this was constantly
   overwriting the segment after the place where argv was stored, which
   was lukely enough on fedora always the environs, which deleted the
   couple first segments. (This was not causing any fuzz, since they
   have been sudo related env vars on the docker image). However, on
   arch this just crashed right away. On Ubuntu this overwrote DISPLAY,
   which resulted in the unability to launch the app.

Reviewed-by: Stefan Schmidt <stefan@datenfreihafen.org>
Differential Revision: https://phab.enlightenment.org/D11600

2 files changed, 20 insertions, 24 deletions

diff --git a/src/bin/exactness/player.c b/src/bin/exactness/player.c
index 1d27863299..bb05f7aeb3 100644
--- a/src/bin/exactness/player.c
+++ b/src/bin/exactness/player.c
@@ -1082,24 +1082,23 @@ int main(int argc, char **argv)
              setenv("FONTCONFIG_FILE", fonts_conf_name, 1);
           }
      }
+   char **new_argv = argv;
+   int new_argc = argc;
 
    if (argv[opt_args])
      {
         /* Replace the current command line to hide the Exactness part */
-        int len = argv[argc - 1] + strlen(argv[argc - 1]) - argv[opt_args];
-        memcpy(argv[0], argv[opt_args], len);
-        memset(argv[0] + len, 0, CMD_LINE_MAX - len);
 
-        int i;
-        for (i = opt_args; i < argc; i++)
+        new_argv = calloc(argc - opt_args + 1, sizeof(char*));
+        new_argc = argc - opt_args;
+
+        for (int i = 0; i < argc - opt_args + 1; ++i)
           {
-             if (i != opt_args)
-               {
-                  argv[i - opt_args] = argv[0] + (argv[i] - argv[opt_args]);
-               }
-             INF("%s ", argv[i - opt_args]);
+             if (i < argc - opt_args)
+               new_argv[i] = argv[opt_args + i];
+             else
+               new_argv[i] = NULL;
           }
-        INF("\n");
      }
    else
      {
@@ -1142,7 +1141,7 @@ int main(int argc, char **argv)
    ecore_evas_callback_new_set(_my_evas_new);
    if (_src_type != FTYPE_REMOTE)
       ecore_idler_add(_src_feed, NULL);
-   pret = ex_prg_invoke(ex_prg_full_path_guess(argv[0]), argc - opt_args, argv, EINA_TRUE);
+   pret = ex_prg_invoke(ex_prg_full_path_guess(new_argv[0]), new_argc, new_argv, EINA_TRUE);
 
    if (_dest && _dest_unit)
      {
diff --git a/src/bin/exactness/recorder.c b/src/bin/exactness/recorder.c
index 11f5bfb1ec..9a33a57c4c 100644
--- a/src/bin/exactness/recorder.c
+++ b/src/bin/exactness/recorder.c
@@ -381,27 +381,24 @@ int main(int argc, char **argv)
      }
 
    /* Replace the current command line to hide the Exactness part */
-   int len = argv[argc - 1] + strlen(argv[argc - 1]) - argv[opt_args];
-   memcpy(argv[0], argv[opt_args], len);
-   memset(argv[0] + len, 0, PATH_MAX - len);
+   char **new_argv;
 
-   int i;
-   for (i = opt_args; i < argc; i++)
+   new_argv = calloc(argc - opt_args + 1, sizeof(char*));
+
+   for (int i = 0; i < argc - opt_args + 1; ++i)
      {
-        if (i != opt_args)
-          {
-             argv[i - opt_args] = argv[0] + (argv[i] - argv[opt_args]);
-          }
-        INF("%s ", argv[i - opt_args]);
+        if (i < argc - opt_args)
+          new_argv[i] = argv[opt_args + i];
+        else
+          new_argv[i] = NULL;
      }
-   INF("\n");
 
    if (!_shot_key) _shot_key = getenv("SHOT_KEY");
    if (!_shot_key) _shot_key = SHOT_KEY_STR;
 
    ecore_evas_callback_new_set(_my_evas_new);
    _last_timestamp = ecore_time_get() * 1000;
-   pret = ex_prg_invoke(ex_prg_full_path_guess(argv[0]), argc - opt_args, argv, EINA_FALSE);
+   pret = ex_prg_invoke(ex_prg_full_path_guess(argv[opt_args]), argc - opt_args, new_argv, EINA_FALSE);
 
    _output_write();
    //free_events(_events_list, EINA_TRUE);