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From:   Luiz Augusto von Dentz <luiz.dentz@gmail.com>
Date:   Mon, 20 Apr 2020 09:57:59 -0700
Message-ID: <CABBYNZ+R1r66mFCNHtgu=RgD_gAeeXuYhk20a0jewmFBa523VA@mail.gmail.com>
Subject: Re: [PATCH 3/4] avctp: Fix compilation with GCC 10
To:     "Gix, Brian" <brian.gix@intel.com>
Cc:     "szymon.janc@codecoup.pl" <szymon.janc@codecoup.pl>,
        "linux-bluetooth@vger.kernel.org" <linux-bluetooth@vger.kernel.org>
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Hi Brian,

On Mon, Apr 20, 2020 at 9:44 AM Gix, Brian <brian.gix@intel.com> wrote:
>
> On Mon, 2020-04-20 at 14:07 +0200, Szymon Janc wrote:
> > This one is a false positive but since we never use more than
> > UINPUT_MAX_NAME_SIZE bytes of name we can silence GCC by reducing
> > size of source string.
> >
> >   CC       profiles/audio/bluetoothd-avctp.o
> > In function =E2=80=98uinput_create=E2=80=99,
> >     inlined from =E2=80=98init_uinput=E2=80=99 at profiles/audio/avctp.=
c:1259:20:
> > profiles/audio/avctp.c:1188:3: error: =E2=80=98strncpy=E2=80=99 output =
may be truncated copying 79 bytes from a string of
> > length 248 [-Werror=3Dstringop-truncation]
> >  1188 |   strncpy(dev.name, name, UINPUT_MAX_NAME_SIZE);
> >       |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > cc1: all warnings being treated as errors
> > ---
> >  profiles/audio/avctp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/profiles/audio/avctp.c b/profiles/audio/avctp.c
> > index 37ffde9e7..058b44a8b 100644
> > --- a/profiles/audio/avctp.c
> > +++ b/profiles/audio/avctp.c
> > @@ -1246,7 +1246,7 @@ static int uinput_create(struct btd_device *devic=
e, const char *name,
> >
> >  static void init_uinput(struct avctp *session)
> >  {
> > -     char name[248 + 1];
> > +     char name[UINPUT_MAX_NAME_SIZE];
>
> Should this be nul terminated?  (UINPUT_MAX_NAME_SIZE + 1)  ?

I guess not since that is send over to the kernel which accepts up to
UINPUT_MAX_NAME_SIZE so if the name is exactly 248 then the kernel
should be the one adding the NULL termination, if it doesn't then we
need to truncate by doing name[247] =3D '\0'.

> >
> >       device_get_name(session->device, name, sizeof(name));
> >       if (g_str_equal(name, "Nokia CK-20W")) {


--=20
Luiz Augusto von Dentz