> From: Takashi Iwai <tiwai@xxxxxxx> > Sent: Tuesday, May 26, 2020 2:22 AM > To: Changming Liu <liu.changm@xxxxxxxxxxxxxxxx> > Cc: perex@xxxxxxxx; alsa-devel@xxxxxxxxxxxxxxxx > Subject: Re: [PATCH] ALSA: hwdep: fix a left shifting 1 by 31 UB bug > > On Tue, 26 May 2020 02:39:21 +0200, > Changming Liu wrote: > > > > The "info.index" variable can be 31 in "1 << info.index". > > This might trigger an undefined behavior since 1 is signed. > > > > Fix this by casting 1 to 1u just to be sure "1u << 31" is defined. > > > > Signed-off-by: Changming Liu <liu.changm@xxxxxxxxxxxxxxxx> > > Thanks for the patch. > > Unfortunately it seems that your MUA modified in quoted-printable and > inapplicable with git-am as is. Since the changes are so small, I > manually applied it now. > I see, thank you very much for pointing out this problem, I'll never use my MUA to send patch again. Also thank you for this manual modification. > Please fix the setup of your MUA at the next time, or better to try > git-send-email to submit directly. > Sorry that I cannot configure my university email to work on git-send-email, I'll use my gmail to send patch via git next time. > > --- > > sound/core/hwdep.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c > > index b412d3b3d5ff..21edb8ac95eb 100644 > > --- a/sound/core/hwdep.c > > +++ b/sound/core/hwdep.c > > @@ -216,12 +216,12 @@ static int snd_hwdep_dsp_load(struct snd_hwdep > *hw, > > if (info.index >= 32) > > return -EINVAL; > > /* check whether the dsp was already loaded */ > > - if (hw->dsp_loaded & (1 << info.index)) > > + if (hw->dsp_loaded & (1u << info.index)) > > return -EBUSY; > > err = hw->ops.dsp_load(hw, &info); > > if (err < 0) > > return err; > > - hw->dsp_loaded |= (1 << info.index); > > + hw->dsp_loaded |= (1u << info.index); > > return 0; > > } > > > > -- > > 2.17.1 > >
