[PATCH 3/3] efi_loader: create common function to free struct efi_disk_obj

[Heinrich Schuchardt]

On 12/25/23 05:43, Masahisa Kojima wrote:
> Current error handling of creating raw disk/partition has
> following issues.
>   - duplicate free for efi handle, efi handle is already freed
>     in efi_delete_handle()

I cannot see where this patch reduces the number of efi_delete_handle()
invocations.

>   - missing free for struct efi_device_path and
>     struct efi_simple_file_system_protocol in some error paths
>
> To address those issue, this commit creates the common function
> to free the struct efi_disk_obj resources and calls it in case
> of error.
>
> Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> ---
>   lib/efi_loader/efi_disk.c | 23 ++++++++++++++++-------
>   1 file changed, 16 insertions(+), 7 deletions(-)
>
> diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
> index 415d8601ba..d2ac2fab9b 100644
> --- a/lib/efi_loader/efi_disk.c
> +++ b/lib/efi_loader/efi_disk.c
> @@ -372,6 +372,19 @@ static int efi_fs_exists(struct blk_desc *desc, int part)
>   	return 1;
>   }
>
> +static void efi_disk_free_diskobj(struct efi_disk_obj *diskobj)
> +{
> +	struct efi_device_path *dp = NULL;

This NULL value is never used.

> +	struct efi_simple_file_system_protocol *volume = NULL;

ditto

> +
> +	dp = diskobj->dp;
> +	volume = diskobj->volume;
> +
> +	efi_delete_handle(&diskobj->header);

efi_delete_handle() may fail.

> +	efi_free_pool(dp);

The device path may only be freed if it has been uninstalled from the
handle.

> +	free(volume);

The simple file protocol interface may only be freed if it has been
uninstalled from the handle.

> +}
> +
>   /**
>    * efi_disk_add_dev() - create a handle for a partition or disk
>    *
> @@ -529,9 +542,7 @@ static efi_status_t efi_disk_add_dev(
>   	}
>   	return EFI_SUCCESS;
>   error:
> -	efi_delete_handle(&diskobj->header);
> -	free(diskobj->volume);
> -	free(diskobj);
> +	efi_disk_free_diskobj(diskobj);
>   	return ret;
>   }
>
> @@ -570,8 +581,7 @@ static int efi_disk_create_raw(struct udevice *dev, efi_handle_t agent_handle)
>   		return ret;
>   	}
>   	if (efi_link_dev(&disk->header, dev)) {
> -		efi_free_pool(disk->dp);
> -		efi_delete_handle(&disk->header);
> +		efi_disk_free_diskobj(disk);
>
>   		return -EINVAL;
>   	}
> @@ -625,8 +635,7 @@ static int efi_disk_create_part(struct udevice *dev, efi_handle_t agent_handle)
>   		return -1;
>   	}
>   	if (efi_link_dev(&disk->header, dev)) {
> -		efi_free_pool(disk->dp);
> -		efi_delete_handle(&disk->header);
> +		efi_disk_free_diskobj(disk);

In efi_disk_add_dev we have opened a protocol interface. We must close
it before removing the partition handle otherwise the disk handle can
never be removed.

To do this all properly we will need to re-implement this code using
proper EFI drivers which expose a driver binding protocol. Please, add a
TODO: comment here that closing the protocol is missing.

Best regards

Heinrich

>
>   		return -1;
>   	}