Re: [PATCH 5/7] efi_loader: PARTITION_UUIDS should be optional

[AKASHI Takahiro <takahiro.akashi@linaro.org>]

On Wed, Apr 20, 2022 at 09:37:39AM +0200, Heinrich Schuchardt wrote:
> On 4/19/22 03:01, AKASHI Takahiro wrote:
> > In the current implementation, partition table support (either GPT or DOS)
> > is not mandatory. So CONFIG_PARTITION_UUIDS should not be enabled
> > (selected) unconditionally.
> > 
> > Fixes: commit 17f8cda505e3 ("efi_loader: set partition GUID in device path for SIG_TYPE_GUID")
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > ---
> >   lib/efi_loader/Kconfig           |  2 +-
> >   lib/efi_loader/efi_device_path.c | 11 ++++++++++-
> >   2 files changed, 11 insertions(+), 2 deletions(-)
> > 
> > diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> > index d50cd2563d3d..bc518d7a413b 100644
> > --- a/lib/efi_loader/Kconfig
> > +++ b/lib/efi_loader/Kconfig
> > @@ -15,7 +15,7 @@ config EFI_LOADER
> >   	depends on !EFI_APP
> >   	default y if !ARM || SYS_CPU = armv7 || SYS_CPU = armv8
> >   	select LIB_UUID
> > -	select PARTITION_UUIDS
> > +	imply PARTITION_UUIDS
> >   	select HAVE_BLOCK_DEVICE
> >   	select REGEX
> >   	imply FAT
> > diff --git a/lib/efi_loader/efi_device_path.c b/lib/efi_loader/efi_device_path.c
> > index 0542aaae16c7..01fb53ae8c40 100644
> > --- a/lib/efi_loader/efi_device_path.c
> > +++ b/lib/efi_loader/efi_device_path.c
> > @@ -864,11 +864,20 @@ static void *dp_part_node(void *buf, struct blk_desc *desc, int part)
> >   			break;
> >   		case SIG_TYPE_GUID:
> 
> This can only be reached for CONFIG_EFI_PARTITION=y.

I know, but the code won't be exercised anyway if !CONFIG_EFI_PARTITION.

> >   			hddp->signature_type = 2;
> > +#if CONFIG_IS_ENABLED(PARTITION_UUIDS)
> > +			/* info.uuid exists only with PARTITION_UUIDS */
> >   			if (uuid_str_to_bin(info.uuid,
> > -					    hddp->partition_signature, 1))
> > +					    hddp->partition_signature, 1)) {
> 
> uuid_guid_get_bin() does not write any byte if info.uuid is not valid.

What matters here is that "uuid" in struct disk_partition is defined
only if CONFIG_PARTITION_UUIDS.

> >   				log_warning(
> >   					"Partition no. %d: invalid guid: %s\n",
> >   					part, info.uuid);
> 
> > +				memset(hddp->partition_signature, 0,
> > +				       sizeof(hddp->partition_signature));
> 
> dp_alloc() already has zeroed out the memory. Please, remove the
> superfluous code.
> 
> > +			}
> > +#else
> > +			memset(hddp->partition_signature, 0,
> > +			       sizeof(hddp->partition_signature));
> 
> ditto.
> 
> 
> This does not conform to the UEFI specification. Why should we support it?

As I said in my previous comment at patch#6,
CONFIG_EFI_PARTITION can be seen optional under the current implementation.

> 
> Shouldn't we select CONFIG_PARTITION_UUIDS if CONFIG_EFI_LOADER=y and
> CONFIG_EFI_PARTITION=y.

Unfortunately some platforms enable (in other words, "select") PARTITION_UUIDS
unconditionally even without explicitly enabling EFI_LOADER or EFI_PARTITION.

-Takahiro Akashi

> Best regards
> 
> Heinrich
> 
> > +#endif
> >   			break;
> >   		}
> > 
>