[PATCH v2 0/2] efinet: correct closing of SNP protocol

[PATCH v2 0/2] efinet: correct closing of SNP protocol

[Heinrich Schuchardt]

In the context of the implementation of the EFI_LOAD_FILE2_PROTOCOL for
the initial ramdisk it was observed that opening the SNP protocol failed
(https://lists.gnu.org/archive/html/grub-devel/2021-10/msg00020.html).
This is due to an incorrect call to CloseProtocol().

This is corrected in the first patch.

The second patch provides a new function grub_efi_close_protocol() to
simplify the coding.

v2:
	do not open SNP protocol non-exclusively
	adjust code style

Heinrich Schuchardt (2):
  efinet: correct closing of SNP protocol
  efi: library function grub_efi_close_protocol()

 grub-core/kern/efi/efi.c           | 12 ++++++++++++
 grub-core/net/drivers/efi/efinet.c | 29 +++++++++++++++++++----------
 include/grub/efi/efi.h             |  3 +++
 3 files changed, 34 insertions(+), 10 deletions(-)

-- 
2.32.0

[PATCH v2 1/2] efinet: correct closing of SNP protocol

[Heinrich Schuchardt]

In the context of the implementation of the EFI_LOAD_FILE2_PROTOCOL for
the initial ramdisk it was observed that opening the SNP protocol failed.
https://lists.gnu.org/archive/html/grub-devel/2021-10/msg00020.html
This is due to an incorrect call to CloseProtocol().

The first parameter of CloseProtocol() is the handle, not the interface.

We call OpenProtocol() with ControllerHandle = NULL. Hence we must also
call CloseProtcol with ControllerHandel = NULL.

Each call of OpenProtocol() for the same network card handle is expected to
return the same interface pointer. If we want to close the protocol which
we opened non-exclusively when searching for a card, we have to do this
before opening the protocol exclusively.

As there is no guarantee that we successfully open the protocol add checks
in the transmit and receive functions.

Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
v2:
	do not open SNP protocol non-exclusively
	adjust code style
---
 grub-core/net/drivers/efi/efinet.c | 31 +++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/grub-core/net/drivers/efi/efinet.c b/grub-core/net/drivers/efi/efinet.c
index 5388f952b..bcd812ff5 100644
--- a/grub-core/net/drivers/efi/efinet.c
+++ b/grub-core/net/drivers/efi/efinet.c
@@ -39,6 +39,9 @@ send_card_buffer (struct grub_net_card *dev,
   grub_uint64_t limit_time = grub_get_time_ms () + 4000;
   void *txbuf;
 
+  if (net == NULL)
+    return grub_error (GRUB_ERR_IO,
+		       N_("network protocol not available, can't send packet"));
   if (dev->txbusy)
     while (1)
       {
@@ -101,6 +104,9 @@ get_card_packet (struct grub_net_card *dev)
   struct grub_net_buff *nb;
   int i;
 
+  if (net == NULL)
+    return NULL;
+
   for (i = 0; i < 2; i++)
     {
       if (!dev->rcvbuf)
@@ -148,12 +154,20 @@ open_card (struct grub_net_card *dev)
 {
   grub_efi_simple_network_t *net;
 
-  /* Try to reopen SNP exlusively to close any active MNP protocol instance
-     that may compete for packet polling
+  if (dev->efi_net != NULL)
+    {
+      efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
+		  dev->efi_handle, &net_io_guid,
+		  grub_efi_image_handle, NULL);
+      dev->efi_net = NULL;
+    }
+  /*
+   * Try to reopen SNP exlusively to close any active MNP protocol instance
+   * that may compete for packet polling
    */
   net = grub_efi_open_protocol (dev->efi_handle, &net_io_guid,
 				GRUB_EFI_OPEN_PROTOCOL_BY_EXCLUSIVE);
-  if (net)
+  if (net != NULL)
     {
       if (net->mode->state == GRUB_EFI_NETWORK_STOPPED
 	  && efi_call_1 (net->start, net) != GRUB_EFI_SUCCESS)
@@ -192,13 +206,12 @@ open_card (struct grub_net_card *dev)
 	  efi_call_6 (net->receive_filters, net, filters, 0, 0, 0, NULL);
 	}
 
-      efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
-		  dev->efi_net, &net_io_guid,
-		  grub_efi_image_handle, dev->efi_handle);
       dev->efi_net = net;
+    } else {
+      return grub_error (GRUB_ERR_NET_NO_CARD, "%s: can't open protocol",
+			 dev->name);
     }
 
-  /* If it failed we just try to run as best as we can */
   return GRUB_ERR_NONE;
 }
 
@@ -208,8 +221,8 @@ close_card (struct grub_net_card *dev)
   efi_call_1 (dev->efi_net->shutdown, dev->efi_net);
   efi_call_1 (dev->efi_net->stop, dev->efi_net);
   efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
-	      dev->efi_net, &net_io_guid,
-	      grub_efi_image_handle, dev->efi_handle);
+	      dev->efi_handle, &net_io_guid,
+	      grub_efi_image_handle, 0);
 }
 
 static struct grub_net_card_driver efidriver =
-- 
2.32.0

[PATCH v2 2/2] efi: library function grub_efi_close_protocol()

[Heinrich Schuchardt]

Create a library function for CloseProtocol() and use it for the SNP
driver.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
v2:
	adjust code style
---
 grub-core/kern/efi/efi.c           | 12 ++++++++++++
 grub-core/net/drivers/efi/efinet.c |  8 ++------
 include/grub/efi/efi.h             |  3 +++
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
index 8cff7be02..d4268d062 100644
--- a/grub-core/kern/efi/efi.c
+++ b/grub-core/kern/efi/efi.c
@@ -117,6 +117,18 @@ grub_efi_open_protocol (grub_efi_handle_t handle,
   return interface;
 }
 
+grub_efi_status_t
+grub_efi_close_protocol (grub_efi_handle_t handle, grub_efi_guid_t *protocol)
+{
+  grub_efi_boot_services_t *b = grub_efi_system_table->boot_services;
+  grub_efi_status_t status;
+
+  status = efi_call_4 (b->close_protocol, handle, protocol,
+		       grub_efi_image_handle, NULL);
+
+  return status;
+}
+
 int
 grub_efi_set_text_mode (int on)
 {
diff --git a/grub-core/net/drivers/efi/efinet.c b/grub-core/net/drivers/efi/efinet.c
index bcd812ff5..186a8a03c 100644
--- a/grub-core/net/drivers/efi/efinet.c
+++ b/grub-core/net/drivers/efi/efinet.c
@@ -156,9 +156,7 @@ open_card (struct grub_net_card *dev)
 
   if (dev->efi_net != NULL)
     {
-      efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
-		  dev->efi_handle, &net_io_guid,
-		  grub_efi_image_handle, NULL);
+      grub_efi_close_protocol (dev->efi_handle, &net_io_guid);
       dev->efi_net = NULL;
     }
   /*
@@ -220,9 +218,7 @@ close_card (struct grub_net_card *dev)
 {
   efi_call_1 (dev->efi_net->shutdown, dev->efi_net);
   efi_call_1 (dev->efi_net->stop, dev->efi_net);
-  efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
-	      dev->efi_handle, &net_io_guid,
-	      grub_efi_image_handle, 0);
+  grub_efi_close_protocol (dev->efi_handle, &net_io_guid);
 }
 
 static struct grub_net_card_driver efidriver =
diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index 83d958f99..12d041f2e 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -35,6 +35,9 @@ EXPORT_FUNC(grub_efi_locate_handle) (grub_efi_locate_search_type_t search_type,
 void *EXPORT_FUNC(grub_efi_open_protocol) (grub_efi_handle_t handle,
 					   grub_efi_guid_t *protocol,
 					   grub_efi_uint32_t attributes);
+grub_efi_status_t
+EXPORT_FUNC(grub_efi_close_protocol) (grub_efi_handle_t handle,
+				      grub_efi_guid_t *protocol);
 int EXPORT_FUNC(grub_efi_set_text_mode) (int on);
 void EXPORT_FUNC(grub_efi_stall) (grub_efi_uintn_t microseconds);
 void *
-- 
2.32.0

Re: [PATCH v2 0/2] efinet: correct closing of SNP protocol

[Daniel Kiper]

On Mon, Nov 29, 2021 at 04:00:27PM +0100, Heinrich Schuchardt wrote:
> In the context of the implementation of the EFI_LOAD_FILE2_PROTOCOL for
> the initial ramdisk it was observed that opening the SNP protocol failed
> (https://lists.gnu.org/archive/html/grub-devel/2021-10/msg00020.html).
> This is due to an incorrect call to CloseProtocol().
>
> This is corrected in the first patch.
>
> The second patch provides a new function grub_efi_close_protocol() to
> simplify the coding.
>
> v2:
> 	do not open SNP protocol non-exclusively
> 	adjust code style
>
> Heinrich Schuchardt (2):
>   efinet: correct closing of SNP protocol
>   efi: library function grub_efi_close_protocol()

For both Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

Thank you for fixing this issue.

Daniel