efi_loader: fix the return codes of UninstallProtocol

Up to now we did not check the return value of DisconnectController.
A previous patch is fixing that taking into account what happened during
the controller disconnect.  But that check takes place before our code
is trying to figure out if the interface exists to begin with.  In case a
driver is not allowed to unbind -- e.g returning EFI_DEVICE_ERROR, we
will end up returning that error instead of EFI_NOT_FOUND.

Add an extra check on the top of the function to make sure the protocol
interface exists before trying to disconnect any drivers

Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index d294db9d8c121777df7817631081718fdbf7d251..2ca7359f3e16df86caee19b5ff4954f98539e91a 100644 (file)
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -1373,6 +1373,8 @@ static efi_status_t efi_uninstall_protocol
        r = efi_search_protocol(handle, protocol, &handler);
        if (r != EFI_SUCCESS)
                goto out;
+       if (handler->protocol_interface != protocol_interface)
+               return EFI_NOT_FOUND;
        /* Disconnect controllers */
        r = efi_disconnect_all_drivers(efiobj, protocol, NULL);
        if (r != EFI_SUCCESS) {