question about "acpi, nfit: validate ars_status output buffer size"

question about "acpi, nfit: validate ars_status output buffer size"

[Dan Carpenter]

Hi Dan,

It's really hard to understand commit 82aa37cf0986 ("acpi, nfit:
validate ars_status output buffer size") from Dec 6, 2016.

drivers/acpi/nfit/core.c
   139                  /* No ARS performed for the current boot */
   140                  if (status = NFIT_ARS_STATUS_NONE)
   141                          return -EAGAIN;
   142  
   143                  /*
   144                   * ARS interrupted, either we overflowed or some other
   145                   * agent wants the scan to stop.  If we didn't overflow
   146                   * then just continue with the returned results.
   147                   */
   148                  if (status = NFIT_ARS_STATUS_INTR) {
   149                          if (ars_status->out_length >= 40 && (ars_status->flags
   150                                                  & NFIT_ARS_F_OVERFLOW))

When I read the commit message, it implies that we're being more strict
about what we process but actually this is && instead of || so we're
being less strict.

The commit message doesn't really describe the user visible effects of
this bug.  I'm not an expert on ACPI and I have grepped the source but
can't figure it out.

Also this isn't aligned the normal way.  It should be:

				if (ars_status->out_length >= 40 &&
				    (ars_status->flags & NFIT_ARS_F_OVERFLOW))

   151                                  return -ENOSPC;
   152                          return 0;
   153                  }

regards,
dan carpenter

Re: question about "acpi, nfit: validate ars_status output buffer size"

[Dan Carpenter]

Oh wow...  I was only reading that one chunk of the commit and I
realized that as soon as I scrolled down.  I'm an idiot.

regards,
dan carpenter

Re: question about "acpi, nfit: validate ars_status output buffer size"

[Marcelo Ricardo Leitner]

On Mon, Jan 09, 2017 at 04:30:07PM +0300, Dan Carpenter wrote:
> Hi Dan,
> 
> It's really hard to understand commit 82aa37cf0986 ("acpi, nfit:
> validate ars_status output buffer size") from Dec 6, 2016.

Dan, you probably hit the wrong mailing list :-)

  Marcelo

Re: question about "acpi, nfit: validate ars_status output buffer size"

[Dan Carpenter]

On Mon, Jan 09, 2017 at 11:38:47AM -0200, Marcelo Ricardo Leitner wrote:
> On Mon, Jan 09, 2017 at 04:30:07PM +0300, Dan Carpenter wrote:
> > Hi Dan,
> > 
> > It's really hard to understand commit 82aa37cf0986 ("acpi, nfit:
> > validate ars_status output buffer size") from Dec 6, 2016.
> 
> Dan, you probably hit the wrong mailing list :-)
> 

Gar...  I'm on a role today.  :P

regards,
dan carpenter