gh-96821: Fix undefined behaviour in audioop.c

Misc/NEWS.d/next/Core and Builtins/2022-09-19-03-35-01.gh-issue-96821.izK6JA.rst

@@ -0,0 +1 @@
+Fix undefined behaviour in ``audioop.c``.

Modules/audioop.c

@@ -59,6 +59,8 @@ static const int16_t seg_uend[8] ={
 static int16_t
 search(int16_t val, const int16_t *table, int size)
 {
+ assert(0 <= size);
+ assert(size < INT16_MAX);
  int i;
 
  for (i = 0; i < size; i++){
@@ -170,6 +172,7 @@ st_14linear2ulaw(int16_t pcm_val) /* 2's complement (14-bit range) */
  if (seg >= 8) /* out of range, return maximum value. */
  return (unsigned char) (0x7F ^ mask);
  else{
+ assert(seg >= 0);
  uval = (unsigned char) (seg << 4) | ((pcm_val >> (seg + 1)) & 0xF);
  return (uval ^ mask);
  }
@@ -300,13 +303,13 @@ static const int stepsizeTable[89] ={
 #ifdef WORDS_BIGENDIAN
 #define GETINT24(cp, i) ( \
  ((unsigned char *)(cp) + (i))[2] + \
- (((unsigned char *)(cp) + (i))[1] << 8) +  \
- (((signed char *)(cp) + (i))[0] << 16) )
+ (((unsigned char *)(cp) + (i))[1] * (1 << 8)) + \
+ (((signed char *)(cp) + (i))[0] * (1 << 16)) )
 #else
 #define GETINT24(cp, i) ( \
  ((unsigned char *)(cp) + (i))[0] + \
- (((unsigned char *)(cp) + (i))[1] << 8) +  \
- (((signed char *)(cp) + (i))[2] << 16) )
+ (((unsigned char *)(cp) + (i))[1] * (1 << 8)) + \
+ (((signed char *)(cp) + (i))[2] * (1 << 16)) )
 #endif
 
 
@@ -347,10 +350,10 @@ static const int stepsizeTable[89] ={
  } while(0)
 
 
-#define GETSAMPLE32(size, cp, i) ( \
- (size == 1) ? (int)GETINT8((cp), (i)) << 24 : \
- (size == 2) ? (int)GETINT16((cp), (i)) << 16 : \
- (size == 3) ? (int)GETINT24((cp), (i)) << 8 : \
+#define GETSAMPLE32(size, cp, i) ( \
+ (size == 1) ? (int)GETINT8((cp), (i)) * (1 << 24) : \
+ (size == 2) ? (int)GETINT16((cp), (i)) * (1 << 16) : \
+ (size == 3) ? (int)GETINT24((cp), (i)) * (1 << 8) : \
  (int)GETINT32((cp), (i)))
 
 #define SETSAMPLE32(size, cp, i, val) do{\
@@ -1558,7 +1561,7 @@ audioop_ulaw2lin_impl(PyObject *module, Py_buffer *fragment, int width)
 
  cp = fragment->buf;
  for (i = 0; i < fragment->len*width; i += width){
- int val = st_ulaw2linear16(*cp++) << 16;
+ int val = st_ulaw2linear16(*cp++) * (1 << 16);
  SETSAMPLE32(width, ncp, i, val);
  }
  return rv;
@@ -1632,7 +1635,7 @@ audioop_alaw2lin_impl(PyObject *module, Py_buffer *fragment, int width)
  cp = fragment->buf;
 
  for (i = 0; i < fragment->len*width; i += width){
- val = st_alaw2linear16(*cp++) << 16;
+ val = st_alaw2linear16(*cp++) * (1 << 16);
  SETSAMPLE32(width, ncp, i, val);
  }
  return rv;
@@ -1757,7 +1760,7 @@ audioop_lin2adpcm_impl(PyObject *module, Py_buffer *fragment, int width,
 
  /* Step 6 - Output value */
  if ( bufferstep ){
- outputbuffer = (delta << 4) & 0xf0;
+ outputbuffer = (delta * (1 << 4)) & 0xf0;
  } else{
  *ncp++ = (delta & 0x0f) | outputbuffer;
  }
@@ -1875,7 +1878,7 @@ audioop_adpcm2lin_impl(PyObject *module, Py_buffer *fragment, int width,
  step = stepsizeTable[index];
 
  /* Step 6 - Output value */
- SETSAMPLE32(width, ncp, i, valpred << 16);
+ SETSAMPLE32(width, ncp, i, valpred * (1 << 16));
  }
 
  rv = Py_BuildValue("(O(ii))", str, valpred, index);