Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date: Fri, 31 Mar 2023 02:33:31 +0200
From: Steffen Nurpmeso <steffen@...oden.eu>
To: Nam Nguyen <namn@...keley.edu>
Cc: oss-security@...ts.openwall.com
Subject: Re: Re: sox: patches for old vulnerabilities

Hello Nam.

Nam Nguyen wrote in
 <87bkk9hljn.fsf@n.m>:
 |Steffen Nurpmeso writes:
 |> Steffen Nurpmeso wrote in
 |>  <20230314201652.RlbWr%steffen@...oden.eu>:
 |>  ...
 |>||Helmut Grohne wrote in
 |>|| <20230314110138.GA1192267@...divi.de>:
 |>|||On Fri, Feb 03, 2023 at 09:44:47PM +0100, Helmut Grohne wrote:
 |>|||>  * CVE-2021-33844
 |>|||
 |>|||The original fix for this issue would cause a regression. After \
 |>|||applying
 |>|||it, sox would be unable to decode WAV GSM files. This has been reported
 ...
 |> libGSM and yes he was right.  So on top of them all a partial undo
 |> of the last is necessary; i will attach the full diff, too.
 |
 |I propose keeping that check in order to fix the regression of not
 |opening wav gsm files.

Oh.  You are surely right.

 |Steffn Nurpmeso's patch with tweaks can be found inline at the end of
 |this email. This patch retains the line 654 hunk and adds line 961 hunk
 |to avoid dividing by 0 for wav gsm files. wav->numSamples is calculated
 |similarly to debian's version of sox.

Not at all.

 |Feedback is welcome as I am not familiar with the code base.

Well me neither (oh i never looked after having seen they use
floating-point internally, many years ago; i never understood why
tremor did not fly for OGG, maybe someone knows).
But yes, i can confirm with your additional condition the Debian
Bug Report thing works, aka GSM.

  #?0|kent:sox.git$ src/sox -t ogg  /x/music/recs.misc/eisler_tucholsky-rosen_auf_den_weg_gestreut.ogg -t wav -e gsm-full-rate ok.wav
  #?0|kent:sox.git$ ALSAPCM=xmix sox ok.wav -t alsa
  sox FAIL formats: can't open input file `ok.wav': WAV file bits per sample is zero
  #?2|kent:sox.git$ ALSAPCM=xmix src/sox ok.wav -t alsa

  ok.wav:

   File Size: 1.18M     Bit Rate: 71.7k
  ...

 |new 961 hunk:

But why do you say 961 repeatedly?  Your lines numbers

 |--8<---------------cut here---------------start------------->8---
 |    967 #ifdef HAVE_LIBGSM
 |    968     case WAVE_FORMAT_GSM610:
 |    969         wav->numSamples = qwDataLength / wav->blockAlign * \
 |    wav->samplesPerBlock;
 |    970         wavgsminit(ft);
 |    971         break;
 |    972 #endif
 |    973
 |    974     }
 |    975
 |    976     if ((!wav->numSamples)
 |    977 #ifdef HAVE_LIBGSM
 |    978         && wav->formatTag != WAVE_FORMAT_GSM610
 |    979 #endif
 |    980     )
 |    981         wav->numSamples = div_bits(qwDataLength, ft->encoding.bits_\
 |    per_sample)
 |    982             / ft->signal.channels;
 |--8<---------------cut here---------------end--------------->8---

are almost right, i now have (after reverting my revert)

  --- a/src/wav.c
  +++ b/src/wav.c
  @@ -972,7 +972,11 @@ static int startread(sox_format_t *ft)
   #endif
       }
  
  -    if (!wav->numSamples)
  +    if (!wav->numSamples
  +#ifdef HAVE_LIBGSM
  +            && wav->formatTag != WAVE_FORMAT_GSM610
  +#endif
  +    )
           wav->numSamples = div_bits(qwDataLength, ft->encoding.bits_per_sample)
               / ft->signal.channels;

so your numbers above are +1 compared to "mine"?
Other than that thanks again.  I did not really look.  (That is,
for functioning GSM.)  Seems to me no more divisions with
numSamples or surrounding that, that is all i know.

Ciao!  (I happily post the entire patch again on request.)

--steffen
|
|Der Kragenbaer,                The moon bear,
|der holt sich munter           he cheerfully and one by one
|einen nach dem anderen runter  wa.ks himself off
|(By Robert Gernhardt)

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.