iLBC: Handle a case of bad input data

webrtc/modules/audio_coding/codecs/ilbc/decode.c

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 10 matching lines @@
 #include "decoder_interpolate_lsf.h"
 #include "index_conv_dec.h"
 #include "do_plc.h"
 #include "constants.h"
 #include "enhancer_interface.h"
 #include "xcorr_coef.h"
 #include "lsf_check.h"
 #include "decode_residual.h"
 #include "unpack_bits.h"
 #include "hp_output.h"
+#include "init_decode.h"
 #ifndef WEBRTC_ARCH_BIG_ENDIAN
 #include "swap_bytes.h"
 #endif
 
 /*----------------------------------------------------------------*
  *  main decoder function
  *---------------------------------------------------------------*/
 
-void WebRtcIlbcfix_DecodeImpl(
+int WebRtcIlbcfix_DecodeImpl(
     int16_t *decblock,    /* (o) decoded signal block */
     const uint16_t *bytes, /* (i) encoded signal bits */
     IlbcDecoder *iLBCdec_inst, /* (i/o) the decoder state
                                            structure */
     int16_t mode      /* (i) 0: bad packet, PLC,
                                                                    1: normal */
                            ) {
+  const int old_mode = iLBCdec_inst->mode;
+  const int old_use_enhancer = iLBCdec_inst->use_enhancer;
+
   size_t i;
   int16_t order_plus_one;
 
   int16_t last_bit;
   int16_t *data;
   /* Stack based */
   int16_t decresidual[BLOCKL_MAX];
   int16_t PLCresidual[BLOCKL_MAX + LPC_FILTERORDER];
   int16_t syntdenum[NSUB_MAX*(LPC_FILTERORDER+1)];
   int16_t PLClpc[LPC_FILTERORDER + 1];
@@ skipping 36 matching lines @@
       /* adjust index */
       WebRtcIlbcfix_IndexConvDec(iLBCbits_inst->cb_index);
 
       /* decode the lsf */
       WebRtcIlbcfix_SimpleLsfDeQ(lsfdeq, (int16_t*)(iLBCbits_inst->lsf), iLBCdec_inst->lpc_n);
       WebRtcIlbcfix_LsfCheck(lsfdeq, LPC_FILTERORDER, iLBCdec_inst->lpc_n);
       WebRtcIlbcfix_DecoderInterpolateLsp(syntdenum, weightdenum,
                                           lsfdeq, LPC_FILTERORDER, iLBCdec_inst);
 
       /* Decode the residual using the cb and gain indexes */
-      WebRtcIlbcfix_DecodeResidual(iLBCdec_inst, iLBCbits_inst, decresidual, syntdenum);
+      if (!WebRtcIlbcfix_DecodeResidual(iLBCdec_inst, iLBCbits_inst,
+                                        decresidual, syntdenum))
+        goto error;
 
       /* preparing the plc for a future loss! */
       WebRtcIlbcfix_DoThePlc(
           PLCresidual, PLClpc, 0, decresidual,
           syntdenum + (LPC_FILTERORDER + 1) * (iLBCdec_inst->nsub - 1),
           iLBCdec_inst->last_lag, iLBCdec_inst);
 
       /* Use the output from doThePLC */
       WEBRTC_SPL_MEMCPY_W16(decresidual, PLCresidual, iLBCdec_inst->blockl);
     }
@@ skipping 120 matching lines @@
                          iLBCdec_inst->blockl);
 
   WEBRTC_SPL_MEMCPY_W16(iLBCdec_inst->old_syntdenum,
                         syntdenum, iLBCdec_inst->nsub*(LPC_FILTERORDER+1));
 
   iLBCdec_inst->prev_enh_pl=0;
 
   if (mode==0) { /* PLC was used */
     iLBCdec_inst->prev_enh_pl=1;
   }
+
+  return 0;  // Success.
+
+error:
+  // The decoder got sick from eating that data. Reset it and return.
+  WebRtcIlbcfix_InitDecode(iLBCdec_inst, old_mode, old_use_enhancer);
+  return -1;  // Error
 }