[PATCH 1/2] efi_loader: multi part device paths to text

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

On Fri, Feb 19, 2021 at 12:45:38PM +0100, Heinrich Schuchardt wrote:
> On 19.02.21 11:13, Ilias Apalodimas wrote:
> > Hi Heinrich
> >
> > On Thu, Feb 18, 2021 at 06:30:43PM +0100, Heinrich Schuchardt wrote:
> >> Our current implementation of
> >> EFI_DEVICE_PATH_TO_TEXT_PROTOCOL.ConvertDevicePathToText() truncates multi
> >> part device paths after the first part. We should convert all parts.
> >>
> >> Render device path instance ends as commas. This is not explicitly
> >> described in the UEFI spec but mimics what EDK II does.
> >>
> >> Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
> >> ---
> >>  lib/efi_loader/efi_device_path_to_text.c | 17 ++++++++++++-----
> >>  1 file changed, 12 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/lib/efi_loader/efi_device_path_to_text.c b/lib/efi_loader/efi_device_path_to_text.c
> >> index 1aaa9f94fa..81b8ac23ba 100644
> >> --- a/lib/efi_loader/efi_device_path_to_text.c
> >> +++ b/lib/efi_loader/efi_device_path_to_text.c
> >> @@ -369,11 +369,18 @@ static uint16_t EFIAPI *efi_convert_device_path_to_text(
> >>
> >>  	if (!device_path)
> >>  		goto out;
> >> -	while (device_path &&
> >> -	       str + MAX_NODE_LEN < buffer + MAX_PATH_LEN) {
> >> -		*str++ = '/';
> >> -		str = efi_convert_single_device_node_to_text(str, device_path);
> >> -		device_path = efi_dp_next(device_path);
> >> +	while (device_path && str + MAX_NODE_LEN < buffer + MAX_PATH_LEN) {
> >> +		if (device_path->type == DEVICE_PATH_TYPE_END) {
> >> +			if (device_path->sub_type !=
> >> +			    DEVICE_PATH_SUB_TYPE_INSTANCE_END)
> >
> > maybe it's better to check explicitly for '== DEVICE_PATH_SUB_TYPE_END'?
> 
> Thank you for reviewing.
> 
> I want to leave the loop when an unexpected value occurs.

Fair enough

Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
> 
> Best regards
> 
> Heinrich
> 
> >
> >> +				break;
> >> +			*str++ = ',';
> >> +		} else {
> >> +			*str++ = '/';
> >> +			str = efi_convert_single_device_node_to_text(
> >> +							str, device_path);
> >> +		}
> >> +		*(u8 **)&device_path += device_path->length;
> >>  	}
> >>
> >>  	text = efi_str_to_u16(buffer);
> >> --
> >> 2.30.0
> >>
> >
> > Cheers
> > /Ilias
> >
>