[U-Boot] [PATCH 1/2] efi_loader: initialize ethernet device path fully

[Patrick Wildt]

On Fri, Mar 23, 2018 at 07:58:07PM +0100, Heinrich Schuchardt wrote:
> On 03/23/2018 07:54 PM, Heinrich Schuchardt wrote:
> >>From c38a011f699cf5a41b48c6fc547f3d0dde3d7cf9 Mon Sep 17 00:00:00 2001
> > From: Patrick Wildt <patrick at blueri.se>
> > Date: Fri, 23 Mar 2018 15:36:58 +0100
> > Subject: [PATCH 1/2] efi_loader: initialize ethernet device path fully
> > 
> > Since the backing memory for a new device path can contain stale
> > data we have to make sure that we either zero the buffer or that
> > we initialize all variables in the overlaying structure.  This
> > fixes setting the boot device path in the loaded image protocol
> > in case we boot from network.>
> > Signed-off-by: Patrick Wildt <patrick at blueri.se>
> > ---
> >  lib/efi_loader/efi_device_path.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/lib/efi_loader/efi_device_path.c
> > b/lib/efi_loader/efi_device_path.c
> > index 3c735e60d3..a086c7bbd4 100644
> > --- a/lib/efi_loader/efi_device_path.c
> > +++ b/lib/efi_loader/efi_device_path.c
> > @@ -777,7 +777,9 @@ struct efi_device_path *efi_dp_from_eth(void)
> >  	ndp->dp.type = DEVICE_PATH_TYPE_MESSAGING_DEVICE;
> >  	ndp->dp.sub_type = DEVICE_PATH_SUB_TYPE_MSG_MAC_ADDR;
> >  	ndp->dp.length = sizeof(*ndp);
> > -	memcpy(ndp->mac.addr, eth_get_ethaddr(), ARP_HLEN);
> > +	memset(&ndp->mac, 0, sizeof(ndp->mac));
> > +	memcpy(&ndp->mac, eth_get_ethaddr(), ARP_HLEN);
> 
> I would prefer if you would set the memory to zero in dp_alloc(). This
> would avoid the observed problem in all device paths.

Sure, I will send another patch to the list which only changes
dp_alloc() to zero the memory.

> 
> > +	ndp->if_type = 1;
> 
> This line does not give any clue what 1 relates to. Please, define a
> constant. EDK uses NET_IFTYPE_ETHERNET = 1.
> 
> The UEFI spec refers to RFC3232. But I could not find the corresponding
> definition there.
> https://www.iana.org/assignments/ianaiftype-mib/ianaiftype-mib uses the
> value 6 for Ethernet interfaces.
> 
> Please, provide the RFC or IANA page from which you have taken the value
> 1 in a comment for the constant.

I guess I should have added /* Ethernet */ as comment, which would be as
precise information as given in the function dp_fill(void) where this
was introduced as part of commit 9dfd84da8ce :

+		/* Ethernet */
+		dp->if_type = 1;

I don't know if setting this even matters, I added it for consistency,
but left out the comment.

Best regards,
Patrick

> Best regards
> 
> Heinrich
> 
> >  	buf = &ndp[1];
> > 
> >  	*((struct efi_device_path *)buf) = END;
> > 
>