kconfig: lxdialog: replace strcpy() with strncpy() in inputbox.c

strcpy() performs no bounds checking and can lead to buffer overflows if
the input string exceeds the destination buffer size. This patch replaces
it with strncpy(), and null terminates the input string.

Signed-off-by: Suchit Karunakaran <suchitkarunakaran@gmail.com>
Reviewed-by: Nicolas Schier <nicolas.schier@linux.dev>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/kconfig/lxdialog/inputbox.c

@@ -39,8 +39,10 @@ int dialog_inputbox(const char *title, const char *prompt, int height, int width
 
 	if (!init)
 		instr[0] = '\0';
-	else
-		strcpy(instr, init);
+	else {
+		strncpy(instr, init, sizeof(dialog_input_result) - 1);
+		instr[sizeof(dialog_input_result) - 1] = '\0';
+	}
 
 do_resize:
 	if (getmaxy(stdscr) <= (height - INPUTBOX_HEIGHT_MIN))