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From:   Todd Kjos <tkjos@google.com>
Date:   Wed, 1 Jun 2022 10:35:16 -0700
Message-ID: <CAHRSSEwMvw2A6N-su40Odbs7AH4EjQ1nVWrrG49aFKUC1PpFug@mail.gmail.com>
Subject: Re: [PATCH] binder: fix sender_euid type in uapi header
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     Carlos Llamas <cmllamas@google.com>, Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Todd Kjos <tkjos@android.com>,
        "Cc: Android Kernel" <kernel-team@android.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Christopher Ferris <cferris@google.com>
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On Wed, Jun 1, 2022 at 9:53 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> On Wed, Jun 1, 2022 at 10:00 AM Carlos Llamas <cmllamas@google.com> wrote:
> >
> > The {pid,uid}_t fields of struct binder_transaction were recently
> > replaced to use kernel types in commit 169adc2b6b3c ("android/binder.h:
> > add linux/android/binder(fs).h to UAPI compile-test coverage").
> >
> > However, using __kernel_uid_t here breaks backwards compatibility in
> > architectures using 16-bits for this type, since glibc and some others
> > still expect a 32-bit uid_t. Instead, let's use __kernel_uid32_t which
> > avoids this compatibility problem.
> >
> > Fixes: 169adc2b6b3c ("android/binder.h: add linux/android/binder(fs).h to UAPI compile-test coverage")
> > Reported-by: Christopher Ferris <cferris@google.com>
> > Signed-off-by: Carlos Llamas <cmllamas@google.com>
> > ---
>
> Ahhh, good catch.
>
> Thank you for fixing this!
>
>  Reviewed-by: Masahiro Yamada <masahiroy@kernel.org>

Acked-by: Todd Kjos <tkjos@google.com>

>
>
> >  include/uapi/linux/android/binder.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
> > index 11157fae8a8e..688bcdaeed53 100644
> > --- a/include/uapi/linux/android/binder.h
> > +++ b/include/uapi/linux/android/binder.h
> > @@ -289,7 +289,7 @@ struct binder_transaction_data {
> >         /* General information about the transaction. */
> >         __u32           flags;
> >         __kernel_pid_t  sender_pid;
> > -       __kernel_uid_t  sender_euid;
> > +       __kernel_uid32_t        sender_euid;
> >         binder_size_t   data_size;      /* number of bytes of data */
> >         binder_size_t   offsets_size;   /* number of bytes of offsets */
> >
> > --
> > 2.36.1.255.ge46751e96f-goog
> >
>
>
> --
> Best Regards
> Masahiro Yamada