Re: [alsa-devel] [PATCH] alsa-lib/tlv: fix handling of raw value ranges

At Tue, 22 May 2012 18:06:34 +0200 (CEST), Benoît Thébaudeau wrote:

Hi Takashi,

Takashi Iwai wrote:

...

It's OK to put an attachment, but I failed to apply it. Please check the patch you sent can be really applied cleanly to alsa-lib git tree.

My copy/paste damaged tabs. Hopefully, this should now work.

Thanks, applied now.

Takashi

Regards, Benoît [2 improve-tlv-raw-val-robustness.patch <text/x-patch (base64)>] alsa-lib/tlv: improve robustness of raw value ranges

snd_tlv_convert_from_dB() relies on rangemin/max blindly. Since this function is exported, it is better for robustness and consistency to parse the range properly, which this patch does.

Signed-off-by: Benoît Thébaudeau benoit.thebaudeau@advansee.com

--- alsa-lib/src/control/tlv.c +++ alsa-lib/src/control/tlv.c @@ -291,41 +291,37 @@ int snd_tlv_convert_from_dB(unsigned int { switch (tlv[0]) { case SND_CTL_TLVT_DB_RANGE: {

• long dbmin, dbmax, prev_rangemax;
  

• long dbmin, dbmax, prev_submax;
  

  unsigned int pos, len; len = int_index(tlv[1]);

• if (len > MAX_TLV_RANGE_SIZE)
  

• if (len < 6 || len > MAX_TLV_RANGE_SIZE)
  return -EINVAL;
  

• if (snd_tlv_get_dB_range(tlv, rangemin, rangemax,
  

• 			 &dbmin, &dbmax))
  

• 	return -EINVAL;
  

• if (db_gain <= dbmin) {
  

• 	*value = rangemin;
  

• 	return 0;
  

• } else if (db_gain >= dbmax) {
  

• 	*value = rangemax;
  

• 	return 0;
  

• }
  

  pos = 2;

• prev_rangemax = 0;
  

• prev_submax = 0;
  

  while (pos + 4 <= len) {

• 	rangemin = (int)tlv[pos];
  

• 	rangemax = (int)tlv[pos + 1];
  

• 	long submin, submax;
  

• 	submin = (int)tlv[pos];
  

• 	submax = (int)tlv[pos + 1];
  

• 	if (rangemax < submax)
  

• 		submax = rangemax;
  if (!snd_tlv_get_dB_range(tlv + pos + 2,
  

• 				  rangemin, rangemax,
  

• 				  submin, submax,
  			  &dbmin, &dbmax) &&
      db_gain >= dbmin && db_gain <= dbmax)
  	return snd_tlv_convert_from_dB(tlv + pos + 2,
  

• 					       rangemin, rangemax,
  

• 					       submin, submax,
  				       db_gain, value, xdir);
  else if (db_gain < dbmin) {
  

• 		*value = xdir ? rangemin : prev_rangemax;
  

• 		*value = xdir || pos == 2 ? submin : prev_submax;
  	return 0;
  }
  

• 	prev_rangemax = rangemax;
  

• 	prev_submax = submax;
  

• 	if (rangemax == submax)
  

• 		break;
  pos += int_index(tlv[pos + 3]) + 4;
  

  }

• return -EINVAL;
  

• *value = prev_submax;
  

• return 0;
  

  } case SND_CTL_TLVT_DB_SCALE: { int min, step, max;