script/execute: Avoid crash when using "$#" outside a function scope

"$#" represents the number of arguments to a function. It is only
defined in a function scope, where "scope" is non-NULL. Currently,
if we attempt to evaluate "$#" outside a function scope, "scope" will
be NULL and we will crash with a NULL pointer dereference.

Do not attempt to count arguments for "$#" if "scope" is NULL. This
will result in "$#" being interpreted as an empty string if evaluated
outside a function scope.

Signed-off-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

diff --git a/grub-core/script/execute.c b/grub-core/script/execute.c
index 3ad468fcea6695e93f3c9189a298360e2c4374cd..b88765f1df7ff92c248797a613a3537c4c0bbd09 100644 (file)
--- a/grub-core/script/execute.c
+++ b/grub-core/script/execute.c
@@ -485,7 +485,7 @@ gettext_putvar (const char *str, grub_size_t len,
     return 0;
 
   /* Enough for any number.  */
-  if (len == 1 && str[0] == '#')
+  if (len == 1 && str[0] == '#' && scope != NULL)
     {
       grub_snprintf (*ptr, 30, "%u", scope->argv.argc);
       *ptr += grub_strlen (*ptr);