patches/audiofile/07_Check-for-multiplication-overflow-in-sfconvert.patch

   1 From: Antonio Larrosa <larrosa@kde.org>
   2 Date: Mon, 6 Mar 2017 13:54:52 +0100
   3 Subject: Check for multiplication overflow in sfconvert
   4
   5 Checks that a multiplication doesn't overflow when
   6 calculating the buffer size, and if it overflows,
   7 reduce the buffer size instead of failing.
   8
   9 This fixes the 00192-audiofile-signintoverflow-sfconvert case
  10 in #41
  11 ---
  12  sfcommands/sfconvert.c | 34 ++++++++++++++++++++++++++++++++--
  13  1 file changed, 32 insertions(+), 2 deletions(-)
  14
  15 diff --git a/sfcommands/sfconvert.c b/sfcommands/sfconvert.c
  16 index 80a1bc4..970a3e4 100644
  17 --- a/sfcommands/sfconvert.c
  18 +++ b/sfcommands/sfconvert.c
  19 @@ -45,6 +45,33 @@ void printusage (void);
  20  void usageerror (void);
  21  bool copyaudiodata (AFfilehandle infile, AFfilehandle outfile, int trackid);
  22
  23 +int firstBitSet(int x)
  24 +{
  25 +        int position=0;
  26 +        while (x!=0)
  27 +        {
  28 +                x>>=1;
  29 +                ++position;
  30 +        }
  31 +        return position;
  32 +}
  33 +
  34 +#ifndef __has_builtin
  35 +#define __has_builtin(x) 0
  36 +#endif
  37 +
  38 +int multiplyCheckOverflow(int a, int b, int *result)
  39 +{
  40 +#if (defined __GNUC__ && __GNUC__ >= 5) || ( __clang__ && __has_builtin(__builtin_mul_overflow))
  41 +       return __builtin_mul_overflow(a, b, result);
  42 +#else
  43 +       if (firstBitSet(a)+firstBitSet(b)>31) // int is signed, so we can't use 32 bits
  44 +               return true;
  45 +       *result = a * b;
  46 +       return false;
  47 +#endif
  48 +}
  49 +
  50  int main (int argc, char **argv)
  51  {
  52         if (argc == 2)
  53 @@ -323,8 +350,11 @@ bool copyaudiodata (AFfilehandle infile, AFfilehandle outfile, int trackid)
  54  {
  55         int frameSize = afGetVirtualFrameSize(infile, trackid, 1);
  56
  57 -       const int kBufferFrameCount = 65536;
  58 -       void *buffer = malloc(kBufferFrameCount * frameSize);
  59 +       int kBufferFrameCount = 65536;
  60 +       int bufferSize;
  61 +       while (multiplyCheckOverflow(kBufferFrameCount, frameSize, &bufferSize))
  62 +               kBufferFrameCount /= 2;
  63 +       void *buffer = malloc(bufferSize);
  64
  65         AFframecount totalFrames = afGetFrameCount(infile, AF_DEFAULT_TRACK);
  66         AFframecount totalFramesWritten = 0;