diff --git a/Misc/NEWS b/Misc/NEWS
index c9b3b9c6527..3aea1f331bf 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -15,6 +15,9 @@ Library
 - Issue #8674: Fixed a number of incorrect or undefined-behaviour-inducing
   overflow checks in the audioop module (CVE-2010-1634).
 
+- Issue #7673: Fix security vulnerability (CVE-2010-2089) in the audioop
+  module, ensure that the input string length is a multiple of the frame size.
+
 
 What's New in Python 2.5.5?
 ===========================
diff --git a/Modules/audioop.c b/Modules/audioop.c
index 12c47671dd1..35c2b437e08 100644
--- a/Modules/audioop.c
+++ b/Modules/audioop.c
@@ -295,6 +295,29 @@ static int stepsizeTable[89] = {
 
 static PyObject *AudioopError;
 
+static int
+audioop_check_size(int size)
+{
+    if (size != 1 && size != 2 && size != 4) {
+        PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
+        return 0;
+    }
+    else
+        return 1;
+}
+
+static int
+audioop_check_parameters(int len, int size)
+{
+    if (!audioop_check_size(size))
+        return 0;
+    if (len % size != 0) {
+        PyErr_SetString(AudioopError, "not a whole number of frames");
+        return 0;
+    }
+    return 1;
+}
+
 static PyObject *
 audioop_getsample(PyObject *self, PyObject *args)
 {
@@ -304,10 +327,8 @@ audioop_getsample(PyObject *self, PyObject *args)
 
         if ( !PyArg_ParseTuple(args, "s#ii:getsample", &cp, &len, &size, &i) )
                 return 0;
-        if ( size != 1 && size != 2 && size != 4 ) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+	        return NULL;
         if ( i < 0 || i >= len/size ) {
                 PyErr_SetString(AudioopError, "Index out of range");
                 return 0;
@@ -328,10 +349,8 @@ audioop_max(PyObject *self, PyObject *args)
 
         if ( !PyArg_ParseTuple(args, "s#i:max", &cp, &len, &size) )
                 return 0;
-        if ( size != 1 && size != 2 && size != 4 ) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
         for ( i=0; i<len; i+= size) {
                 if ( size == 1 )      val = (int)*CHARP(cp, i);
                 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
@@ -352,10 +371,8 @@ audioop_minmax(PyObject *self, PyObject *args)
 
         if (!PyArg_ParseTuple(args, "s#i:minmax", &cp, &len, &size))
                 return NULL;
-        if (size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
+        if (!audioop_check_parameters(len, size))
                 return NULL;
-        }
         for (i = 0; i < len; i += size) {
                 if (size == 1) val = (int) *CHARP(cp, i);
                 else if (size == 2) val = (int) *SHORTP(cp, i);
@@ -376,10 +393,8 @@ audioop_avg(PyObject *self, PyObject *args)
 
         if ( !PyArg_ParseTuple(args, "s#i:avg", &cp, &len, &size) )
                 return 0;
-        if ( size != 1 && size != 2 && size != 4 ) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
         for ( i=0; i<len; i+= size) {
                 if ( size == 1 )      val = (int)*CHARP(cp, i);
                 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
@@ -403,10 +418,8 @@ audioop_rms(PyObject *self, PyObject *args)
 
         if ( !PyArg_ParseTuple(args, "s#i:rms", &cp, &len, &size) )
                 return 0;
-        if ( size != 1 && size != 2 && size != 4 ) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
         for ( i=0; i<len; i+= size) {
                 if ( size == 1 )      val = (int)*CHARP(cp, i);
                 else if ( size == 2 ) val = (int)*SHORTP(cp, i);
@@ -609,10 +622,8 @@ audioop_avgpp(PyObject *self, PyObject *args)
 
         if ( !PyArg_ParseTuple(args, "s#i:avgpp", &cp, &len, &size) )
                 return 0;
-        if ( size != 1 && size != 2 && size != 4 ) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
         /* Compute first delta value ahead. Also automatically makes us
         ** skip the first extreme value
         */
@@ -666,10 +677,8 @@ audioop_maxpp(PyObject *self, PyObject *args)
 
         if ( !PyArg_ParseTuple(args, "s#i:maxpp", &cp, &len, &size) )
                 return 0;
-        if ( size != 1 && size != 2 && size != 4 ) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
         /* Compute first delta value ahead. Also automatically makes us
         ** skip the first extreme value
         */
@@ -717,10 +726,8 @@ audioop_cross(PyObject *self, PyObject *args)
 
         if ( !PyArg_ParseTuple(args, "s#i:cross", &cp, &len, &size) )
                 return 0;
-        if ( size != 1 && size != 2 && size != 4 ) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
         ncross = -1;
         prevval = 17; /* Anything <> 0,1 */
         for ( i=0; i<len; i+= size) {
@@ -745,6 +752,8 @@ audioop_mul(PyObject *self, PyObject *args)
 
         if ( !PyArg_ParseTuple(args, "s#id:mul", &cp, &len, &size, &factor ) )
                 return 0;
+        if (!audioop_check_parameters(len, size))
+                return NULL;
     
         if ( size == 1 ) maxval = (double) 0x7f;
         else if ( size == 2 ) maxval = (double) 0x7fff;
@@ -787,6 +796,12 @@ audioop_tomono(PyObject *self, PyObject *args)
         if ( !PyArg_ParseTuple(args, "s#idd:tomono",
 	                       &cp, &len, &size, &fac1, &fac2 ) )
                 return 0;
+        if (!audioop_check_parameters(len, size))
+                return NULL;
+        if (((len / size) & 1) != 0) {
+                PyErr_SetString(AudioopError, "not a whole number of frames");
+                return NULL;
+        }
     
         if ( size == 1 ) maxval = (double) 0x7f;
         else if ( size == 2 ) maxval = (double) 0x7fff;
@@ -832,6 +847,8 @@ audioop_tostereo(PyObject *self, PyObject *args)
         if ( !PyArg_ParseTuple(args, "s#idd:tostereo",
 	                       &cp, &len, &size, &fac1, &fac2 ) )
                 return 0;
+        if (!audioop_check_parameters(len, size))
+                return NULL;
     
         if ( size == 1 ) maxval = (double) 0x7f;
         else if ( size == 2 ) maxval = (double) 0x7fff;
@@ -890,7 +907,8 @@ audioop_add(PyObject *self, PyObject *args)
         if ( !PyArg_ParseTuple(args, "s#s#i:add",
                           &cp1, &len1, &cp2, &len2, &size ) )
                 return 0;
-
+        if (!audioop_check_parameters(len1, size))
+                return NULL;
         if ( len1 != len2 ) {
                 PyErr_SetString(AudioopError, "Lengths should be the same");
                 return 0;
@@ -945,10 +963,8 @@ audioop_bias(PyObject *self, PyObject *args)
                           &cp, &len, &size , &bias) )
                 return 0;
 
-        if ( size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
     
         rv = PyString_FromStringAndSize(NULL, len);
         if ( rv == 0 )
@@ -981,10 +997,8 @@ audioop_reverse(PyObject *self, PyObject *args)
                           &cp, &len, &size) )
                 return 0;
 
-        if ( size != 1 && size != 2 && size != 4 ) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
     
         rv = PyString_FromStringAndSize(NULL, len);
         if ( rv == 0 )
@@ -1018,11 +1032,10 @@ audioop_lin2lin(PyObject *self, PyObject *args)
                           &cp, &len, &size, &size2) )
                 return 0;
 
-        if ( (size != 1 && size != 2 && size != 4) ||
-             (size2 != 1 && size2 != 2 && size2 != 4)) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
+        if (!audioop_check_size(size2))
+                return NULL;
     
         if (len/size > INT_MAX/size2) {
                 PyErr_SetString(PyExc_MemoryError,
@@ -1072,10 +1085,8 @@ audioop_ratecv(PyObject *self, PyObject *args)
 	                      &nchannels, &inrate, &outrate, &state,
 			      &weightA, &weightB))
                 return NULL;
-        if (size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
+        if (!audioop_check_size(size))
                 return NULL;
-        }
         if (nchannels < 1) {
                 PyErr_SetString(AudioopError, "# of channels should be >= 1");
                 return NULL;
@@ -1252,10 +1263,8 @@ audioop_lin2ulaw(PyObject *self, PyObject *args)
                                &cp, &len, &size) )
                 return 0 ;
 
-        if ( size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+            return NULL;
     
         rv = PyString_FromStringAndSize(NULL, len/size);
         if ( rv == 0 )
@@ -1286,10 +1295,8 @@ audioop_ulaw2lin(PyObject *self, PyObject *args)
                                &cp, &len, &size) )
                 return 0;
 
-        if ( size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
     
         if (len > INT_MAX/size) {
                 PyErr_SetString(PyExc_MemoryError,
@@ -1325,10 +1332,8 @@ audioop_lin2alaw(PyObject *self, PyObject *args)
                                &cp, &len, &size) )
                 return 0;
 
-        if ( size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
     
         rv = PyString_FromStringAndSize(NULL, len/size);
         if ( rv == 0 )
@@ -1359,10 +1364,8 @@ audioop_alaw2lin(PyObject *self, PyObject *args)
                                &cp, &len, &size) )
                 return 0;
 
-        if ( size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
     
         if (len > INT_MAX/size) {
                 PyErr_SetString(PyExc_MemoryError,
@@ -1399,12 +1402,9 @@ audioop_lin2adpcm(PyObject *self, PyObject *args)
                                &cp, &len, &size, &state) )
                 return 0;
     
+        if (!audioop_check_parameters(len, size))
+                return NULL;
 
-        if ( size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
-    
         str = PyString_FromStringAndSize(NULL, len/(size*2));
         if ( str == 0 )
                 return 0;
@@ -1507,10 +1507,8 @@ audioop_adpcm2lin(PyObject *self, PyObject *args)
                                &cp, &len, &size, &state) )
                 return 0;
 
-        if ( size != 1 && size != 2 && size != 4) {
-                PyErr_SetString(AudioopError, "Size should be 1, 2 or 4");
-                return 0;
-        }
+        if (!audioop_check_parameters(len, size))
+                return NULL;
     
         /* Decode state, should have (value, step) */
         if ( state == Py_None ) {