[FFmpeg-devel] [PATCH 3/3] avcodec/lpc: Avoid floating point division by 0 in compute_ref_coefs()

[Michael Niedermayer]

Fixes: Ticket7996
Fixes: CVE-2020-20445

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/lpc.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/lpc.h b/libavcodec/lpc.h
index 88ca247f87..52170fd623 100644
--- a/libavcodec/lpc.h
+++ b/libavcodec/lpc.h
@@ -143,7 +143,7 @@ static inline void compute_ref_coefs(const LPC_TYPE *autoc, int max_order,
         gen0[i] = gen1[i] = autoc[i + 1];
 
     err    = autoc[0];
-    ref[0] = -gen1[0] / err;
+    ref[0] = -gen1[0] / ((USE_FIXED || err) ? err : 1);
     err   +=  gen1[0] * ref[0];
     if (error)
         error[0] = err;
@@ -152,7 +152,7 @@ static inline void compute_ref_coefs(const LPC_TYPE *autoc, int max_order,
             gen1[j] = gen1[j + 1] + ref[i - 1] * gen0[j];
             gen0[j] = gen1[j + 1] * ref[i - 1] + gen0[j];
         }
-        ref[i] = -gen1[0] / err;
+        ref[i] = -gen1[0] / ((USE_FIXED || err) ? err : 1);
         err   +=  gen1[0] * ref[i];
         if (error)
             error[i] = err;
-- 
2.17.1