Re: [Patch] firmware: dmi_scan: fix dmi scan to handle "End of Table" structure

[Ivan Khoronzhuk]

On 02/04/2015 04:04 PM, Ard Biesheuvel wrote:
> On 4 February 2015 at 13:57, Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> wrote:
> > The dmi-sysfs should create "End of Table" entry, that is type 127.
> > But after adding initial SMBIOS v3 support the 127-0 entry is not
> > handled any more, as result it's not created in sysfs.
> > This is important because the size of whole DMI table must correspond
> > to sum of all DMI entry sizes.
> >
> > Of-course, it can be handled in newly introduced libdmifs by adding
> > end entry virtually, but it's brake backward compatibility and don't
> > correspond to SMBIOS DMI table size read from SMBIOS entry point
> > structure.
> >
> > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx>
> > ---
> >   drivers/firmware/dmi_scan.c | 6 ------
> >   1 file changed, 6 deletions(-)
> >
> > diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
> > index c5f7b4e..c63e5e5 100644
> > --- a/drivers/firmware/dmi_scan.c
> > +++ b/drivers/firmware/dmi_scan.c
> > @@ -93,12 +93,6 @@ static void dmi_table(u8 *buf, int len, int num,
> >                  const struct dmi_header *dm = (const struct dmi_header *)data;
> >
> >                  /*
> > -                * 7.45 End-of-Table (Type 127) [SMBIOS reference spec v3.0.0]
> > -                */
> > -               if (dm->type == DMI_ENTRY_END_OF_TABLE)
> > -                       break;
> > -
> > -               /*
> >                   *  We want to know the total length (formatted area and
> >                   *  strings) before decoding to make sure we won't run off the
> >                   *  table in dmi_decode or dmi_string
> This is not the right way to fix this: the end-of-table check needs to
> be done, because the v3 entry point does not contain the actual length
> of the data, but only an upper bound, and there may be trailing
> garbage.
>
> So apparently, I put this check and break in the wrong place, and we
> should place it after the decode() call instead, but not remove it.

Ok.
I'll send v2.
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