diff mbox series

[v2] efi_loader: make efi_delete_handle() follow the EFI spec

Message ID 20230724101736.21821-1-ilias.apalodimas@linaro.org
State New
Headers show
Series [v2] efi_loader: make efi_delete_handle() follow the EFI spec | expand

Commit Message

Ilias Apalodimas July 24, 2023, 10:17 a.m. UTC 
The EFI doesn't allow removal of handles, unless all hosted protocols
are cleanly removed.  Our efi_delete_handle() is a bit intrusive.
Although it does try to delete protocols before removing a handle,
it doesn't care if that fails.  Instead it only returns an error if the
handle is invalid. On top of that none of the callers of that function
check the return code.

So let's rewrite this in a way that fits the EFI spec better.  Instead
of forcing the handle removal, gracefully uninstall all the handle
protocols.  According to the EFI spec when the last protocol is removed
the handle will be deleted.  Also switch all the callers and check the
return code. Some callers can't do anything useful apart from reporting
an error.  The disk related functions on the other hand, can prevent a
medium that is being used by EFI from removal.

The only function that doesn't check the result is efi_delete_image().
But that function needs a bigger rework anyway, so we can clean it up in
the future

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
---
Changes since v1:
- only report errors internally in efi_delete_handle()

 cmd/bootefi.c                 | 21 ++++++---------------
 include/efi_loader.h          |  2 +-
 lib/efi_driver/efi_uclass.c   | 12 +++++-------
 lib/efi_loader/efi_boottime.c | 20 ++++++++++++++------
 lib/efi_loader/efi_disk.c     |  6 +++++-
 5 files changed, 31 insertions(+), 30 deletions(-)

--
2.40.1

Comments

Heinrich Schuchardt July 28, 2023, 7:06 a.m. UTC | #1 
On 7/24/23 12:17, Ilias Apalodimas wrote:
> The EFI doesn't allow removal of handles, unless all hosted protocols
> are cleanly removed.  Our efi_delete_handle() is a bit intrusive.
> Although it does try to delete protocols before removing a handle,
> it doesn't care if that fails.  Instead it only returns an error if the
> handle is invalid. On top of that none of the callers of that function
> check the return code.
>
> So let's rewrite this in a way that fits the EFI spec better.  Instead
> of forcing the handle removal, gracefully uninstall all the handle
> protocols.  According to the EFI spec when the last protocol is removed
> the handle will be deleted.  Also switch all the callers and check the
> return code. Some callers can't do anything useful apart from reporting
> an error.  The disk related functions on the other hand, can prevent a
> medium that is being used by EFI from removal.
>
> The only function that doesn't check the result is efi_delete_image().
> But that function needs a bigger rework anyway, so we can clean it up in
> the future
>
> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> ---
> Changes since v1:
> - only report errors internally in efi_delete_handle()
>
>   cmd/bootefi.c                 | 21 ++++++---------------
>   include/efi_loader.h          |  2 +-
>   lib/efi_driver/efi_uclass.c   | 12 +++++-------
>   lib/efi_loader/efi_boottime.c | 20 ++++++++++++++------
>   lib/efi_loader/efi_disk.c     |  6 +++++-
>   5 files changed, 31 insertions(+), 30 deletions(-)
>
> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
> index 5c0afec1544d..f73d6eb0e2d8 100644
> --- a/cmd/bootefi.c
> +++ b/cmd/bootefi.c
> @@ -606,20 +606,6 @@ failure:
>   	return ret;
>   }
>
> -/**
> - * bootefi_run_finish() - finish up after running an EFI test
> - *
> - * @loaded_image_info: Pointer to a struct which holds the loaded image info
> - * @image_obj: Pointer to a struct which holds the loaded image object
> - */
> -static void bootefi_run_finish(struct efi_loaded_image_obj *image_obj,
> -			       struct efi_loaded_image *loaded_image_info)
> -{
> -	efi_restore_gd();
> -	free(loaded_image_info->load_options);
> -	efi_delete_handle(&image_obj->header);
> -}
> -
>   /**
>    * do_efi_selftest() - execute EFI selftest
>    *
> @@ -638,7 +624,12 @@ static int do_efi_selftest(void)
>
>   	/* Execute the test */
>   	ret = EFI_CALL(efi_selftest(&image_obj->header, &systab));
> -	bootefi_run_finish(image_obj, loaded_image_info);
> +	efi_restore_gd();
> +	free(loaded_image_info->load_options);
> +	if (ret != EFI_SUCCESS)
> +		efi_delete_handle(&image_obj->header);
> +	else
> +		ret = efi_delete_handle(&image_obj->header);
>
>   	return ret != EFI_SUCCESS;
>   }
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index b5fa0fe01ded..3a64eb9c6672 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -629,7 +629,7 @@ void efi_add_handle(efi_handle_t obj);
>   /* Create handle */
>   efi_status_t efi_create_handle(efi_handle_t *handle);
>   /* Delete handle */
> -void efi_delete_handle(efi_handle_t obj);
> +efi_status_t efi_delete_handle(efi_handle_t obj);
>   /* Call this to validate a handle and find the EFI object for it */
>   struct efi_object *efi_search_obj(const efi_handle_t handle);
>   /* Locate device_path handle */
> diff --git a/lib/efi_driver/efi_uclass.c b/lib/efi_driver/efi_uclass.c
> index 45f935198874..66a45e156d60 100644
> --- a/lib/efi_driver/efi_uclass.c
> +++ b/lib/efi_driver/efi_uclass.c
> @@ -285,10 +285,8 @@ static efi_status_t efi_add_driver(struct driver *drv)
>   	bp->ops = ops;
>
>   	ret = efi_create_handle(&bp->bp.driver_binding_handle);
> -	if (ret != EFI_SUCCESS) {
> -		free(bp);
> -		goto out;
> -	}
> +	if (ret != EFI_SUCCESS)
> +		goto err;
>   	bp->bp.image_handle = bp->bp.driver_binding_handle;
>   	ret = efi_add_protocol(bp->bp.driver_binding_handle,
>   			       &efi_guid_driver_binding_protocol, bp);
> @@ -299,11 +297,11 @@ static efi_status_t efi_add_driver(struct driver *drv)
>   		if (ret != EFI_SUCCESS)
>   			goto err;
>   	}
> -out:
> -	return ret;
>
> +	return ret;
>   err:
> -	efi_delete_handle(bp->bp.driver_binding_handle);
> +	if (bp->bp.driver_binding_handle)
> +		efi_delete_handle(bp->bp.driver_binding_handle);
>   	free(bp);
>   	return ret;
>   }
> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> index 052fe481e473..0e89c8505b11 100644
> --- a/lib/efi_loader/efi_boottime.c
> +++ b/lib/efi_loader/efi_boottime.c
> @@ -59,6 +59,10 @@ static efi_handle_t current_image;
>   static volatile gd_t *efi_gd, *app_gd;
>   #endif
>
> +static efi_status_t efi_uninstall_protocol
> +			(efi_handle_t handle, const efi_guid_t *protocol,
> +			 void *protocol_interface);
> +
>   /* 1 if inside U-Boot code, 0 if inside EFI payload code */
>   static int entry_count = 1;
>   static int nesting_level;
> @@ -610,8 +614,8 @@ static efi_status_t efi_remove_all_protocols(const efi_handle_t handle)
>   	list_for_each_entry_safe(protocol, pos, &efiobj->protocols, link) {
>   		efi_status_t ret;
>
> -		ret = efi_remove_protocol(handle, &protocol->guid,
> -					  protocol->protocol_interface);
> +		ret = efi_uninstall_protocol(handle, &protocol->guid,
> +					     protocol->protocol_interface);
>   		if (ret != EFI_SUCCESS)
>   			return ret;
>   	}
> @@ -622,19 +626,23 @@ static efi_status_t efi_remove_all_protocols(const efi_handle_t handle)
>    * efi_delete_handle() - delete handle
>    *
>    * @handle: handle to delete
> + *
> + * Return: status code
>    */
> -void efi_delete_handle(efi_handle_t handle)
> +efi_status_t efi_delete_handle(efi_handle_t handle)
>   {
>   	efi_status_t ret;
>
>   	ret = efi_remove_all_protocols(handle);
> -	if (ret == EFI_INVALID_PARAMETER) {
> -		log_err("Can't remove invalid handle %p\n", handle);
> -		return;
> +	if (ret != EFI_SUCCESS) {
> +		log_err("Handle %p has protocols installed. Unable to delete\n", handle);
> +		return ret;
>   	}
>
>   	list_del(&handle->link);
>   	free(handle);
> +
> +	return ret;
>   }
>
>   /**
> diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
> index 28c8cdf7100e..8983b86886b3 100644
> --- a/lib/efi_loader/efi_disk.c
> +++ b/lib/efi_loader/efi_disk.c
> @@ -708,6 +708,7 @@ int efi_disk_remove(void *ctx, struct event *event)
>   	efi_handle_t handle;
>   	struct blk_desc *desc;
>   	struct efi_disk_obj *diskobj = NULL;
> +	efi_status_t ret;
>
>   	if (dev_tag_get_ptr(dev, DM_TAG_EFI, (void **)&handle))
>   		return 0;
> @@ -727,10 +728,13 @@ int efi_disk_remove(void *ctx, struct event *event)
>   		return 0;
>   	}
>
> +	ret = efi_delete_handle(handle);
> +	if (ret != EFI_SUCCESS)
> +		return -1;

I guess we should add a comment here explaining that the DM device
should not be removed if there still are open protocols for the handle.

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

> +
>   	if (diskobj)
>   		efi_free_pool(diskobj->dp);
>
> -	efi_delete_handle(handle);
>   	dev_tag_del(dev, DM_TAG_EFI);
>
>   	return 0;
> --
> 2.40.1
>
diff mbox series

Patch

diff --git a/cmd/bootefi.c b/cmd/bootefi.c
index 5c0afec1544d..f73d6eb0e2d8 100644
--- a/cmd/bootefi.c
+++ b/cmd/bootefi.c
@@ -606,20 +606,6 @@  failure:
 	return ret;
 }

-/**
- * bootefi_run_finish() - finish up after running an EFI test
- *
- * @loaded_image_info: Pointer to a struct which holds the loaded image info
- * @image_obj: Pointer to a struct which holds the loaded image object
- */
-static void bootefi_run_finish(struct efi_loaded_image_obj *image_obj,
-			       struct efi_loaded_image *loaded_image_info)
-{
-	efi_restore_gd();
-	free(loaded_image_info->load_options);
-	efi_delete_handle(&image_obj->header);
-}
-
 /**
  * do_efi_selftest() - execute EFI selftest
  *
@@ -638,7 +624,12 @@  static int do_efi_selftest(void)

 	/* Execute the test */
 	ret = EFI_CALL(efi_selftest(&image_obj->header, &systab));
-	bootefi_run_finish(image_obj, loaded_image_info);
+	efi_restore_gd();
+	free(loaded_image_info->load_options);
+	if (ret != EFI_SUCCESS)
+		efi_delete_handle(&image_obj->header);
+	else
+		ret = efi_delete_handle(&image_obj->header);

 	return ret != EFI_SUCCESS;
 }
diff --git a/include/efi_loader.h b/include/efi_loader.h
index b5fa0fe01ded..3a64eb9c6672 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -629,7 +629,7 @@  void efi_add_handle(efi_handle_t obj);
 /* Create handle */
 efi_status_t efi_create_handle(efi_handle_t *handle);
 /* Delete handle */
-void efi_delete_handle(efi_handle_t obj);
+efi_status_t efi_delete_handle(efi_handle_t obj);
 /* Call this to validate a handle and find the EFI object for it */
 struct efi_object *efi_search_obj(const efi_handle_t handle);
 /* Locate device_path handle */
diff --git a/lib/efi_driver/efi_uclass.c b/lib/efi_driver/efi_uclass.c
index 45f935198874..66a45e156d60 100644
--- a/lib/efi_driver/efi_uclass.c
+++ b/lib/efi_driver/efi_uclass.c
@@ -285,10 +285,8 @@  static efi_status_t efi_add_driver(struct driver *drv)
 	bp->ops = ops;

 	ret = efi_create_handle(&bp->bp.driver_binding_handle);
-	if (ret != EFI_SUCCESS) {
-		free(bp);
-		goto out;
-	}
+	if (ret != EFI_SUCCESS)
+		goto err;
 	bp->bp.image_handle = bp->bp.driver_binding_handle;
 	ret = efi_add_protocol(bp->bp.driver_binding_handle,
 			       &efi_guid_driver_binding_protocol, bp);
@@ -299,11 +297,11 @@  static efi_status_t efi_add_driver(struct driver *drv)
 		if (ret != EFI_SUCCESS)
 			goto err;
 	}
-out:
-	return ret;

+	return ret;
 err:
-	efi_delete_handle(bp->bp.driver_binding_handle);
+	if (bp->bp.driver_binding_handle)
+		efi_delete_handle(bp->bp.driver_binding_handle);
 	free(bp);
 	return ret;
 }
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 052fe481e473..0e89c8505b11 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -59,6 +59,10 @@  static efi_handle_t current_image;
 static volatile gd_t *efi_gd, *app_gd;
 #endif

+static efi_status_t efi_uninstall_protocol
+			(efi_handle_t handle, const efi_guid_t *protocol,
+			 void *protocol_interface);
+
 /* 1 if inside U-Boot code, 0 if inside EFI payload code */
 static int entry_count = 1;
 static int nesting_level;
@@ -610,8 +614,8 @@  static efi_status_t efi_remove_all_protocols(const efi_handle_t handle)
 	list_for_each_entry_safe(protocol, pos, &efiobj->protocols, link) {
 		efi_status_t ret;

-		ret = efi_remove_protocol(handle, &protocol->guid,
-					  protocol->protocol_interface);
+		ret = efi_uninstall_protocol(handle, &protocol->guid,
+					     protocol->protocol_interface);
 		if (ret != EFI_SUCCESS)
 			return ret;
 	}
@@ -622,19 +626,23 @@  static efi_status_t efi_remove_all_protocols(const efi_handle_t handle)
  * efi_delete_handle() - delete handle
  *
  * @handle: handle to delete
+ *
+ * Return: status code
  */
-void efi_delete_handle(efi_handle_t handle)
+efi_status_t efi_delete_handle(efi_handle_t handle)
 {
 	efi_status_t ret;

 	ret = efi_remove_all_protocols(handle);
-	if (ret == EFI_INVALID_PARAMETER) {
-		log_err("Can't remove invalid handle %p\n", handle);
-		return;
+	if (ret != EFI_SUCCESS) {
+		log_err("Handle %p has protocols installed. Unable to delete\n", handle);
+		return ret;
 	}

 	list_del(&handle->link);
 	free(handle);
+
+	return ret;
 }

 /**
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
index 28c8cdf7100e..8983b86886b3 100644
--- a/lib/efi_loader/efi_disk.c
+++ b/lib/efi_loader/efi_disk.c
@@ -708,6 +708,7 @@  int efi_disk_remove(void *ctx, struct event *event)
 	efi_handle_t handle;
 	struct blk_desc *desc;
 	struct efi_disk_obj *diskobj = NULL;
+	efi_status_t ret;

 	if (dev_tag_get_ptr(dev, DM_TAG_EFI, (void **)&handle))
 		return 0;
@@ -727,10 +728,13 @@  int efi_disk_remove(void *ctx, struct event *event)
 		return 0;
 	}

+	ret = efi_delete_handle(handle);
+	if (ret != EFI_SUCCESS)
+		return -1;
+
 	if (diskobj)
 		efi_free_pool(diskobj->dp);

-	efi_delete_handle(handle);
 	dev_tag_del(dev, DM_TAG_EFI);

 	return 0;