perf script: Add array bound checking to list_scripts

Don't overflow array when the scripts directory is too large, or the
script file name is too long.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20190311144502.15423-11-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-script.c

@@ -2982,7 +2982,8 @@ static int check_ev_match(char *dir_name, char *scriptname,
  * will list all statically runnable scripts, select one, execute it and
  * show the output in a perf browser.
  */
-int find_scripts(char **scripts_array, char **scripts_path_array)
+int find_scripts(char **scripts_array, char **scripts_path_array, int num,
+		 int pathlen)
 {
 	struct dirent *script_dirent, *lang_dirent;
 	char scripts_path[MAXPATHLEN], lang_path[MAXPATHLEN];
@@ -3027,7 +3028,10 @@ int find_scripts(char **scripts_array, char **scripts_path_array)
 			/* Skip those real time scripts: xxxtop.p[yl] */
 			if (strstr(script_dirent->d_name, "top."))
 				continue;
-			sprintf(scripts_path_array[i], "%s/%s", lang_path,
+			if (i >= num)
+				break;
+			snprintf(scripts_path_array[i], pathlen, "%s/%s",
+				lang_path,
 				script_dirent->d_name);
 			temp = strchr(script_dirent->d_name, '.');
 			snprintf(scripts_array[i],

tools/perf/builtin.h

@@ -40,5 +40,6 @@ int cmd_mem(int argc, const char **argv);
 int cmd_data(int argc, const char **argv);
 int cmd_ftrace(int argc, const char **argv);
 
-int find_scripts(char **scripts_array, char **scripts_path_array);
+int find_scripts(char **scripts_array, char **scripts_path_array, int num,
+		 int pathlen);
 #endif

tools/perf/ui/browsers/scripts.c

@@ -97,7 +97,8 @@ static int list_scripts(char *script_name, bool *custom,
 		paths[i] = names[i] + SCRIPT_NAMELEN;
 	}
 
-	num = find_scripts(names + max_std, paths + max_std);
+	num = find_scripts(names + max_std, paths + max_std, SCRIPT_MAX_NO - max_std,
+			SCRIPT_FULLPATH_LEN);
 	if (num < 0)
 		num = 0;
 	choice = ui__popup_menu(num + max_std, (char * const *)names);