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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Clemens Ladisch <clemens@ladisch.de>
Cc: Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>,
	alsa-devel@alsa-project.org, kernel-janitors@vger.kernel.org
Subject: Re: [alsa-devel] [patch] ALSA: seq_midi_emul: small array underflow
Date: Tue, 3 Mar 2015 14:38:48 +0300	[thread overview]
Message-ID: <20150303113848.GD5437@mwanda> (raw)
In-Reply-To: <54F5993E.7000109@ladisch.de>

On Tue, Mar 03, 2015 at 12:21:34PM +0100, Clemens Ladisch wrote:
> Dan Carpenter wrote:
> > In snd_opl3_calc_pitch() then the limit is:
> >
> > 	if (pitchbend > 0x1FFF)
> > 		pitchbend = 0x1FFF;
> >
> > But it can underflow meaning that segment can be as low as
> > SHORT_MIN / 0x1000 and we can read 6 elements before the start of the
> > opl3_note_table[] array.
> 
> > -	short midi_pitchbend;		/* Pitch bend amount */
> > +	unsigned short midi_pitchbend;	/* Pitch bend amount */
> 
> Pitch bend is a signed 14-bit value.  What is wrong is the missing
> check for the lower bound.
> 

Thanks for the review.  I will resend.

regards,
dan carpenter


WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com>
To: Clemens Ladisch <clemens@ladisch.de>
Cc: Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.de>,
	alsa-devel@alsa-project.org, kernel-janitors@vger.kernel.org
Subject: Re: [alsa-devel] [patch] ALSA: seq_midi_emul: small array underflow
Date: Tue, 03 Mar 2015 11:38:48 +0000	[thread overview]
Message-ID: <20150303113848.GD5437@mwanda> (raw)
In-Reply-To: <54F5993E.7000109@ladisch.de>

On Tue, Mar 03, 2015 at 12:21:34PM +0100, Clemens Ladisch wrote:
> Dan Carpenter wrote:
> > In snd_opl3_calc_pitch() then the limit is:
> >
> > 	if (pitchbend > 0x1FFF)
> > 		pitchbend = 0x1FFF;
> >
> > But it can underflow meaning that segment can be as low as
> > SHORT_MIN / 0x1000 and we can read 6 elements before the start of the
> > opl3_note_table[] array.
> 
> > -	short midi_pitchbend;		/* Pitch bend amount */
> > +	unsigned short midi_pitchbend;	/* Pitch bend amount */
> 
> Pitch bend is a signed 14-bit value.  What is wrong is the missing
> check for the lower bound.
> 

Thanks for the review.  I will resend.

regards,
dan carpenter


  reply	other threads:[~2015-03-03 11:38 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-03  9:38 [patch] ALSA: seq_midi_emul: small array underflow Dan Carpenter
2015-03-03  9:38 ` Dan Carpenter
2015-03-03 11:21 ` [alsa-devel] " Clemens Ladisch
2015-03-03 11:21   ` Clemens Ladisch
2015-03-03 11:38   ` Dan Carpenter [this message]
2015-03-03 11:38     ` Dan Carpenter
2015-03-03 19:13   ` [patch v2] ALSA: opl3: " Dan Carpenter
2015-03-03 19:13     ` Dan Carpenter
2015-03-03 20:59     ` [alsa-devel] " Clemens Ladisch
2015-03-03 20:59       ` Clemens Ladisch
2015-03-03 21:06       ` Dan Carpenter
2015-03-03 21:06         ` Dan Carpenter

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