linux-kernel - Re: [PATCH v2 3/5] Creates macro to avoid variable shadowing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Mon, 29 Oct 2018 21:32:05 -0300
From:   Leonardo Bras <leobras.c@...il.com>
To:     Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc:     lkcamp@...ts.libreplanetbr.org, Borislav Petkov <bp@...en8.de>,
        David.Laight@...lab.com, Andy Lutomirski <luto@...nel.org>,
        Ingo Molnar <mingo@...nel.org>, Helen Koike <helen@...keco.de>,
        Michal Marek <michal.lkml@...kovi.net>,
        linux-kbuild@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 3/5] Creates macro to avoid variable shadowing

Thank you!
On Sun, Oct 28, 2018 at 1:38 PM Masahiro Yamada
<yamada.masahiro@...ionext.com> wrote:
>
> On Tue, Oct 23, 2018 at 10:11 AM Leonardo Brás <leobras.c@...il.com> wrote:
> >
> > Creates DEF_FIELD_ADDR_VAR as a more generic version of the DEF_FIELD_ADD
> > macro, allowing usage of a variable name other than the struct element name.
> > Also, sets DEF_FIELD_ADDR as a specific usage of DEF_FILD_ADDR_VAR in which
> > the var name is the same as the struct element name.
> >
> > Signed-off-by: Leonardo Brás <leobras.c@...il.com>
> > ---
>
>
> Applied to linux-kbuild.
>
>
>
> >  scripts/mod/file2alias.c | 24 +++++++++++++++++-------
> >  1 file changed, 17 insertions(+), 7 deletions(-)
> >
> > diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
> > index 7be43697ff84..3015c0bdecb2 100644
> > --- a/scripts/mod/file2alias.c
> > +++ b/scripts/mod/file2alias.c
> > @@ -95,12 +95,20 @@ extern struct devtable *__start___devtable[], *__stop___devtable[];
> >   */
> >  #define DEF_FIELD(m, devid, f) \
> >         typeof(((struct devid *)0)->f) f = TO_NATIVE(*(typeof(f) *)((m) + OFF_##devid##_##f))
> > +
> > +/* Define a variable v that holds the address of field f of struct devid
> > + * based at address m.  Due to the way typeof works, for a field of type
> > + * T[N] the variable has type T(*)[N], _not_ T*.
> > + */
> > +#define DEF_FIELD_ADDR_VAR(m, devid, f, v) \
> > +       typeof(((struct devid *)0)->f) *v = ((m) + OFF_##devid##_##f)
> > +
> >  /* Define a variable f that holds the address of field f of struct devid
> >   * based at address m.  Due to the way typeof works, for a field of type
> >   * T[N] the variable has type T(*)[N], _not_ T*.
> >   */
> >  #define DEF_FIELD_ADDR(m, devid, f) \
> > -       typeof(((struct devid *)0)->f) *f = ((m) + OFF_##devid##_##f)
> > +       DEF_FIELD_ADDR_VAR(m, devid, f, f)
> >
> >  /* Add a table entry.  We test function type matches while we're here. */
> >  #define ADD_TO_DEVTABLE(device_id, type, function) \
> > @@ -641,25 +649,27 @@ static void do_pnp_card_entries(void *symval, unsigned long size,
> >         unsigned int i;
> >
> >         device_id_check(mod->name, "pnp", size, id_size, symval);
> > +       DEF_FIELD_ADDR(symval, pnp_card_device_id, devs);
> > +       typeof(devs) devs_last;
> >
> >         for (i = 0; i < count; i++) {
> >                 unsigned int j;
> > -               DEF_FIELD_ADDR(symval + i*id_size, pnp_card_device_id, devs);
> > +               devs_last = devs + i * id_size;
> >
> >                 for (j = 0; j < PNP_MAX_DEVICES; j++) {
> > -                       const char *id = (char *)(*devs)[j].id;
> > -                       int i2, j2;
> > +                       const char *id = (char *)(*devs_last)[j].id;
> > +                       int j2;
> >                         int dup = 0;
> >
> >                         if (!id[0])
> >                                 break;
> >
> >                         /* find duplicate, already added value */
> > -                       for (i2 = 0; i2 < i && !dup; i2++) {
> > -                               DEF_FIELD_ADDR(symval + i2*id_size, pnp_card_device_id, devs);
> > +                       while ((devs_last -= id_size) >= devs && !dup) {
> >
> >                                 for (j2 = 0; j2 < PNP_MAX_DEVICES; j2++) {
> > -                                       const char *id2 = (char *)(*devs)[j2].id;
> > +                                       const char *id2 =
> > +                                               (char *)(*devs_last)[j2].id;
> >
> >                                         if (!id2[0])
> >                                                 break;
> > --
> > 2.19.1
> >
>
>
> --
> Best Regards
> Masahiro Yamada