efi_loader: delete handle from events when a protocol is uninstalled

When a notification event is registered for a protocol the handle of the
protocol is added in our event notification list.  When all the protocols
of the handle are uninstalled we delete the handle but we do not remove
it from the event notification list.

Clean up the protocol removal functions and add a wrapper which
- Removes the to-be deleted handle from any lists it participates
- Remove the handle if no more protocols are present

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index 0e89c8505b11e8e4ad833c1bb7dae02f1eb7474d..0b7579cb5af1698f648ada6aee2cd26823198531 100644 (file)
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -61,7 +61,7 @@ static volatile gd_t *efi_gd, *app_gd;
 
 static efi_status_t efi_uninstall_protocol
                        (efi_handle_t handle, const efi_guid_t *protocol,
-                        void *protocol_interface);
+                        void *protocol_interface, bool preserve);
 
 /* 1 if inside U-Boot code, 0 if inside EFI payload code */
 static int entry_count = 1;
@@ -207,6 +207,36 @@ static bool efi_event_is_queued(struct efi_event *event)
        return !!event->queue_link.next;
 }
 
+/**
+ * efi_purge_handle() - Clean the deleted handle from the various lists
+ * @handle: handle to remove
+ *
+ * Return: status code
+ */
+static efi_status_t efi_purge_handle(efi_handle_t handle)
+{
+       struct efi_register_notify_event *item;
+
+       if (!list_empty(&handle->protocols))
+               return EFI_ACCESS_DENIED;
+       /* The handle is about to be freed. Remove it from events */
+       list_for_each_entry(item, &efi_register_notify_events, link) {
+               struct efi_protocol_notification *hitem, *hnext;
+
+               list_for_each_entry_safe(hitem, hnext, &item->handles, link) {
+                       if (handle == hitem->handle) {
+                               list_del(&hitem->link);
+                               free(hitem);
+                       }
+               }
+       }
+       /* The last protocol has been removed, delete the handle. */
+       list_del(&handle->link);
+       free(handle);
+
+       return EFI_SUCCESS;
+}
+
 /**
  * efi_process_event_queue() - process event queue
  */
@@ -615,7 +645,7 @@ static efi_status_t efi_remove_all_protocols(const efi_handle_t handle)
                efi_status_t ret;
 
                ret = efi_uninstall_protocol(handle, &protocol->guid,
-                                            protocol->protocol_interface);
+                                            protocol->protocol_interface, true);
                if (ret != EFI_SUCCESS)
                        return ret;
        }
@@ -639,10 +669,7 @@ efi_status_t efi_delete_handle(efi_handle_t handle)
                return ret;
        }
 
-       list_del(&handle->link);
-       free(handle);
-
-       return ret;
+       return efi_purge_handle(handle);
 }
 
 /**
@@ -1356,6 +1383,8 @@ reconnect:
  * @handle:             handle from which the protocol shall be removed
  * @protocol:           GUID of the protocol to be removed
  * @protocol_interface: interface to be removed
+ * @preserve:          preserve or delete the handle and remove it from any
+ *                     list it participates if no protocols remain
  *
  * This function DOES NOT delete a handle without installed protocol.
  *
@@ -1363,7 +1392,7 @@ reconnect:
  */
 static efi_status_t efi_uninstall_protocol
                        (efi_handle_t handle, const efi_guid_t *protocol,
-                        void *protocol_interface)
+                        void *protocol_interface, bool preserve)
 {
        struct efi_handler *handler;
        struct efi_open_protocol_info_item *item;
@@ -1397,6 +1426,14 @@ static efi_status_t efi_uninstall_protocol
                goto out;
        }
        r = efi_remove_protocol(handle, protocol, protocol_interface);
+       if (r != EFI_SUCCESS)
+               return r;
+       /*
+        * We don't care about the return value here since the
+        * handle might have more protocols installed
+        */
+       if (!preserve)
+               efi_purge_handle(handle);
 out:
        return r;
 }
@@ -1422,15 +1459,10 @@ static efi_status_t EFIAPI efi_uninstall_protocol_interface
 
        EFI_ENTRY("%p, %pUs, %p", handle, protocol, protocol_interface);
 
-       ret = efi_uninstall_protocol(handle, protocol, protocol_interface);
+       ret = efi_uninstall_protocol(handle, protocol, protocol_interface, false);
        if (ret != EFI_SUCCESS)
                goto out;
 
-       /* If the last protocol has been removed, delete the handle. */
-       if (list_empty(&handle->protocols)) {
-               list_del(&handle->link);
-               free(handle);
-       }
 out:
        return EFI_EXIT(ret);
 }
@@ -2785,7 +2817,7 @@ static efi_status_t EFIAPI
 efi_uninstall_multiple_protocol_interfaces_int(efi_handle_t handle,
                                               efi_va_list argptr)
 {
-       const efi_guid_t *protocol;
+       const efi_guid_t *protocol, *next_protocol;
        void *protocol_interface;
        efi_status_t ret = EFI_SUCCESS;
        size_t i = 0;
@@ -2795,25 +2827,34 @@ efi_uninstall_multiple_protocol_interfaces_int(efi_handle_t handle,
                return EFI_INVALID_PARAMETER;
 
        efi_va_copy(argptr_copy, argptr);
+       protocol = efi_va_arg(argptr, efi_guid_t*);
        for (;;) {
-               protocol = efi_va_arg(argptr, efi_guid_t*);
+               /*
+                * If efi_uninstall_protocol() fails we need to be able to
+                * reinstall the previously uninstalled protocols on the same
+                * handle.
+                * Instead of calling efi_uninstall_protocol(...,..., false)
+                * and potentially removing the handle, only allow the handle
+                * removal on the last protocol that we requested to uninstall.
+                * That way we can preserve  the handle in case the latter fails
+                */
+               bool preserve = true;
+
                if (!protocol)
                        break;
                protocol_interface = efi_va_arg(argptr, void*);
+               next_protocol = efi_va_arg(argptr, efi_guid_t*);
+               if (!next_protocol)
+                       preserve = false;
                ret = efi_uninstall_protocol(handle, protocol,
-                                            protocol_interface);
+                                            protocol_interface, preserve);
                if (ret != EFI_SUCCESS)
                        break;
                i++;
+               protocol = next_protocol;
        }
-       if (ret == EFI_SUCCESS) {
-               /* If the last protocol has been removed, delete the handle. */
-               if (list_empty(&handle->protocols)) {
-                       list_del(&handle->link);
-                       free(handle);
-               }
+       if (ret == EFI_SUCCESS)
                goto out;
-       }
 
        /* If an error occurred undo all changes. */
        for (; i; --i) {
@@ -3712,7 +3753,7 @@ static efi_status_t EFIAPI efi_reinstall_protocol_interface(
                  new_interface);
 
        /* Uninstall protocol but do not delete handle */
-       ret = efi_uninstall_protocol(handle, protocol, old_interface);
+       ret = efi_uninstall_protocol(handle, protocol, old_interface, true);
        if (ret != EFI_SUCCESS)
                goto out;