[PATCH] net/route: Fix NULL pointer dereference when deleting last route

[Jeremy Kerr]

Currently, grub_cmd_delroute will crash when deleting the last route.
In the deletion code, we remove the matching route from the route list:
      
  *prev = route->next
      
- route->next being NULL to mark the end of the list. We then process
the for loop's iterator, which contains:

  prev = &((*prev)->next)

ie,

  prev = NULL->next;

Instead, break out of the for-loop when we've deleted the route.

        * grub-core/net/net.c (grub_cmd_delroute): fix NULL deref when deleting
        last route

---
 grub-core/net/net.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/grub-core/net/net.c b/grub-core/net/net.c
index 09acea9..cafec41 100644
--- a/grub-core/net/net.c
+++ b/grub-core/net/net.c
@@ -430,6 +430,7 @@ grub_cmd_delroute (struct grub_command *cmd __attribute__ 
((unused)),
        *prev = route->next;
        grub_free (route->name);
        grub_free (route);
+       break;
       }
 
   return GRUB_ERR_NONE;