net/http: Do not tear down socket if it's already been torn down

It's possible for data->sock to get torn down in tcp error handling.
If we unconditionally tear it down again we will end up doing writes
to an offset of the NULL pointer when we go to tear it down again.

Detect if it has been torn down and don't do it again.

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

diff --git a/grub-core/net/http.c b/grub-core/net/http.c
index 3fe155f1be9cd25fabf6bd80696f5603816f8c95..ef6eaff0d91b27a0a5919e26cbcd4d28f30b378f 100644 (file)
--- a/grub-core/net/http.c
+++ b/grub-core/net/http.c
@@ -422,7 +422,7 @@ http_establish (struct grub_file *file, grub_off_t offset, int initial)
       return err;
     }
 
-  for (i = 0; !data->headers_recv && i < 100; i++)
+  for (i = 0; data->sock && !data->headers_recv && i < 100; i++)
     {
       grub_net_tcp_retransmit ();
       grub_net_poll_cards (300, &data->headers_recv);
@@ -430,7 +430,8 @@ http_establish (struct grub_file *file, grub_off_t offset, int initial)
 
   if (!data->headers_recv)
     {
-      grub_net_tcp_close (data->sock, GRUB_NET_TCP_ABORT);
+      if (data->sock)
+        grub_net_tcp_close (data->sock, GRUB_NET_TCP_ABORT);
       if (data->err)
        {
          char *str = data->errmsg;