[xiph-commits] r12765 - trunk/speex/libspeex

[jm at svn.xiph.org]

Author: jm
Date: 2007-03-15 16:32:36 -0700 (Thu, 15 Mar 2007)
New Revision: 12765

Modified:
   trunk/speex/libspeex/filters.c
   trunk/speex/libspeex/filters.h
   trunk/speex/libspeex/nb_celp.c
Log:
Doing some sanity checking (just in case) on the propagated long-term
prediction


Modified: trunk/speex/libspeex/filters.c
===================================================================
--- trunk/speex/libspeex/filters.c	2007-03-15 13:13:25 UTC (rev 12764)
+++ trunk/speex/libspeex/filters.c	2007-03-15 23:32:36 UTC (rev 12765)
@@ -62,6 +62,24 @@
    }
 }
 
+void sanitize_values32(spx_word32_t *vec, spx_word32_t min_val, spx_word32_t max_val, int len)
+{
+   int i;
+   for (i=0;i<len;i++)
+   {
+      /* It's important we do the test that way so we can catch NaNs, which are neither greater nor smaller */
+      if (!(vec[i]>=min_val && vec[i] <= max_val))
+      {
+         if (vec[i] < min_val)
+            vec[i] = min_val;
+         else if (vec[i] > max_val)
+            vec[i] = max_val;
+         else /* Has to be NaN */
+            vec[i] = 0;
+      }
+   }
+}
+
 void highpass(const spx_word16_t *x, spx_word16_t *y, int len, int filtID, spx_mem_t *mem)
 {
    int i;

Modified: trunk/speex/libspeex/filters.h
===================================================================
--- trunk/speex/libspeex/filters.h	2007-03-15 13:13:25 UTC (rev 12764)
+++ trunk/speex/libspeex/filters.h	2007-03-15 23:32:36 UTC (rev 12765)
@@ -67,6 +67,7 @@
 
 /* Apply bandwidth expansion on LPC coef */
 void bw_lpc(spx_word16_t , const spx_coef_t *lpc_in, spx_coef_t *lpc_out, int order);
+void sanitize_values32(spx_word32_t *vec, spx_word32_t min_val, spx_word32_t max_val, int len);
 
 
 void syn_percep_zero16(const spx_word16_t *xx, const spx_coef_t *ak, const spx_coef_t *awk1, const spx_coef_t *awk2, spx_word16_t *y, int N, int ord, char *stack);

Modified: trunk/speex/libspeex/nb_celp.c
===================================================================
--- trunk/speex/libspeex/nb_celp.c	2007-03-15 13:13:25 UTC (rev 12764)
+++ trunk/speex/libspeex/nb_celp.c	2007-03-15 23:32:36 UTC (rev 12765)
@@ -1526,7 +1526,11 @@
 #ifdef EPIC_48K
          }
 #endif
-
+         /* Ensuring that things aren't blowing up as would happen if e.g. an encoder is 
+         crafting packets to make us produce NaNs and slow down the decoder (vague DoS threat).
+         We can probably be even more aggressive and limit to 15000 or so. */
+         sanitize_values32(exc32, NEG32(QCONST32(32000,SIG_SHIFT-1)), QCONST32(32000,SIG_SHIFT-1), st->subframeSize);
+         
          tmp = gain_3tap_to_1tap(pitch_gain);
 
          pitch_average += tmp;