commit 2d79f3ac5944f3924bd895c22cdcb993dac97a4d
author Shashank Pathmudi <shashank.pathmudi@ittiam.com> Thu Oct 05 15:15:23 2023 +0530
committer sandeshvenkatesh <89826624+sandeshvenkatesh@users.noreply.github.com> Thu Oct 05 16:01:11 2023 +0530
tree fd85d6bad7bdecffb38d80b5754b43180be386eb
parent 0c86a5d8fabe7ab275ff56caed9e4293e627c525

Fix for divide-by-zero in ixheaacd_sbr_env_calc

These changes handle the divide-by-zero runtime error reported
while calculating energy gain.

Bug: ossFuzz:62903
Test: poc in bug

decoder/ixheaacd_esbr_envcal.c

diff --git a/decoder/ixheaacd_esbr_envcal.c b/decoder/ixheaacd_esbr_envcal.c
index ebf4ae7..677c616 100644
--- a/decoder/ixheaacd_esbr_envcal.c
+++ b/decoder/ixheaacd_esbr_envcal.c
@@ -150,6 +150,7 @@
   WORD32 band_loop_end;
 
   WORD32 rate = upsamp_4_flag ? 4 : 2;
+  FLOAT64 guard = 1e-17;
 
   if (ldmps_present == 1) rate = 1;
 
@@ -349,7 +350,7 @@
             nrg_tone_pvc[c][t] = 0.0f;
 
             tmp = frame_data->qmapped_pvc[c][t] /
-                  (1 + frame_data->qmapped_pvc[c][t]);
+                  (1 + frame_data->qmapped_pvc[c][t] + guard);
 
             if (flag) {
               nrg_gain_pvc[c][t] = (FLOAT32)sqrt(nrg_ref_pvc[c][t] * tmp /
@@ -359,7 +360,7 @@
                   (harmonics[c] && (t >= frame_data->sine_position ||
                                     (*harm_flag_prev)[c + sub_band_start]))
                       ? sqrt(nrg_ref_pvc[c][t] * tmp /
-                             frame_data->qmapped_pvc[c][t])
+                             (frame_data->qmapped_pvc[c][t] + guard))
                       : nrg_tone_pvc[c][t]);
 
               nrg_tone_pvc[c][t] = (FLOAT32)(
@@ -376,7 +377,7 @@
               } else {
                 nrg_gain_pvc[c][t] = (FLOAT32)sqrt(
                     nrg_ref_pvc[c][t] * tmp /
-                    ((nrg_est_pvc[c][t] + 1) * frame_data->qmapped_pvc[c][t]));
+                    ((nrg_est_pvc[c][t] + 1) * (frame_data->qmapped_pvc[c][t] + guard)));
               }
             }
 
@@ -400,7 +401,7 @@
                k < (*lim_table)[limiter_band][c + 1]; k++) {
             if (g_max <= nrg_gain_pvc[k][t]) {
               noise_level_pvc[k][t] =
-                  noise_level_pvc[k][t] * (g_max / nrg_gain_pvc[k][t]);
+                  (FLOAT32)(noise_level_pvc[k][t] * (g_max / (nrg_gain_pvc[k][t] + guard)));
               nrg_gain_pvc[k][t] = g_max;
             }
 
@@ -473,7 +474,7 @@
             nrg_tone_pvc[c][t] = 0.0f;
 
             tmp = frame_data->qmapped_pvc[c][t] /
-                  (1 + frame_data->qmapped_pvc[c][t]);
+                  (1 + frame_data->qmapped_pvc[c][t] + guard);
 
             if (flag) {
               nrg_gain_pvc[c][t] = (FLOAT32)sqrt(nrg_ref_pvc[c][t] * tmp /
@@ -483,7 +484,7 @@
                   (harmonics[c] && (t >= frame_data->sine_position ||
                                     (*harm_flag_prev)[c + sub_band_start]))
                       ? sqrt(nrg_ref_pvc[c][t] * tmp /
-                             frame_data->qmapped_pvc[c][t])
+                             (frame_data->qmapped_pvc[c][t] + guard))
                       : nrg_tone_pvc[c][t]);
             } else {
               if (noise_absc_flag) {
@@ -492,7 +493,7 @@
               } else {
                 nrg_gain_pvc[c][t] = (FLOAT32)sqrt(
                     nrg_ref_pvc[c][t] * tmp /
-                    ((nrg_est_pvc[c][t] + 1) * frame_data->qmapped_pvc[c][t]));
+                    ((nrg_est_pvc[c][t] + 1) * (frame_data->qmapped_pvc[c][t] + guard)));
               }
             }
 
@@ -645,7 +646,7 @@
           ui2 = frame_data->pstr_sbr_header->pstr_freq_band_data
                     ->freq_band_tbl_noise[o + 1];
 
-          if (p_frame_info->border_vec[i] == p_frame_info->border_vec[i + 1]) {
+          if (p_frame_info->border_vec[i] >= p_frame_info->border_vec[i + 1]) {
             for (flag = 0, k = li; k < ui; k++) {
               flag = (harmonics[c] &&
                 (i >= trans_env || (*harm_flag_prev)[c + sub_band_start]))
@@ -677,7 +678,6 @@
           c -= (ui - li);
 
           for (k = 0; k < ui - li; k++) {
-            FLOAT64 guard = 1e-17;
             o = (k + li >= ui2) ? o + 1 : o;
             if (o >= MAX_NOISE_COEFFS) {
               if (ec_flag)
@@ -691,7 +691,7 @@
             nrg_est[c] = (!int_mode) ? nrg : nrg_est[c];
             nrg_tone[c] = 0;
             tmp = noise_floor[next * num_nf_bands + o] /
-                  (1 + noise_floor[next * num_nf_bands + o]);
+                  (1 + noise_floor[next * num_nf_bands + o] + guard);
             if (flag) {
               nrg_gain[c] = (FLOAT32)sqrt(nrg_ref[c] * tmp / (nrg_est[c] + 1));
               nrg_tone[c] = (FLOAT32)(
@@ -728,7 +728,7 @@
           for (k = (*lim_table)[limiter_band][c];
                k < (*lim_table)[limiter_band][c + 1]; k++) {
             if (g_max <= nrg_gain[k]) {
-              noise_level[k] = noise_level[k] * (g_max / nrg_gain[k]);
+              noise_level[k] = (FLOAT32)(noise_level[k] * (g_max / (nrg_gain[k] + guard)));
               nrg_gain[k] = g_max;
             }
           }