Re: [PATCH v2] scripts: headers_install: Exit with error on config leak

[Siddharth Gupta]

On 5/4/2020 12:18 AM, Masahiro Yamada wrote:
> On Sun, May 3, 2020 at 12:29 PM Siddharth Gupta <sidgup@xxxxxxxxxxxxxx> wrote:
> > Misuse of CONFIG_* in UAPI headers should result in an error as it exposes
> > configuration of different targets to userspace.
>
> Sorry, I missed to point out this.
>
> This statement is not precious; it does not expose the kernel
> configuration at all.
>
> include/generated/autoconf.h is not available from userspace.
> So, all the CONFIG options are undefined.
>
> Could you reword the commit somehow?
Sure. I just meant that if a CONFIG_* is present in the UAPI header it 
can be set in a
userspace application that includes the header to manipulate the control 
flow in a
kernel that might support multiple targets.

I'll update the commit text and send out an updated patch.

Thanks,
Siddharth

> > Signed-off-by: Siddharth Gupta <sidgup@xxxxxxxxxxxxxx>
> > ---
> >   scripts/headers_install.sh | 11 ++++++-----
> >   1 file changed, 6 insertions(+), 5 deletions(-)
> >
> > diff --git a/scripts/headers_install.sh b/scripts/headers_install.sh
> > index a07668a..94a8335 100755
> > --- a/scripts/headers_install.sh
> > +++ b/scripts/headers_install.sh
> > @@ -64,7 +64,7 @@ configs=$(sed -e '
> >          d
> >   ' $OUTFILE)
> >
> > -# The entries in the following list are not warned.
> > +# The entries in the following list do not result in an error.
> >   # Please do not add a new entry. This list is only for existing ones.
> >   # The list will be reduced gradually, and deleted eventually. (hopefully)
> >   #
> > @@ -98,18 +98,19 @@ include/uapi/linux/raw.h:CONFIG_MAX_RAW_DEVS
> >
> >   for c in $configs
> >   do
> > -       warn=1
> > +       leak_error=1
> >
> >          for ignore in $config_leak_ignores
> >          do
> >                  if echo "$INFILE:$c" | grep -q "$ignore$"; then
> > -                       warn=
> > +                       leak_error=
> >                          break
> >                  fi
> >          done
> >
> > -       if [ "$warn" = 1 ]; then
> > -               echo "warning: $INFILE: leak $c to user-space" >&2
> > +       if [ "$leak_error" = 1 ]; then
> > +               echo "error: $INFILE: leak $c to user-space" >&2
> > +               exit 1
> >          fi
> >   done
> >
> > --
> > Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> > a Linux Foundation Collaborative Project