From a671e181286785d8fdd69f8ec17c5814727d32f7 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Mon, 21 Mar 2022 20:51:47 +0100
Subject: [PATCH] avcodec/diracdec: avoid signed integer overflow in global mv

Fixes: signed integer overflow: -128275513086 * -76056576 cannot be represented in type 'long'
Fixes: 45818/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_DIRAC_fuzzer-5129799149944832

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 7f1279684e8e1e33c78577b7f0265c062e4e6232)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/diracdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c
index ed42bc366a..b1d82ed3e1 100644
--- a/libavcodec/diracdec.c
+++ b/libavcodec/diracdec.c
@@ -1431,8 +1431,8 @@ static void global_mv(DiracContext *s, DiracBlock *block, int x, int y, int ref)
     int *c      = s->globalmc[ref].perspective;
 
     int64_t m   = (1<<ep) - (c[0]*(int64_t)x + c[1]*(int64_t)y);
-    int64_t mx  = m * (int64_t)((A[0][0] * (int64_t)x + A[0][1]*(int64_t)y) + (1LL<<ez) * b[0]);
-    int64_t my  = m * (int64_t)((A[1][0] * (int64_t)x + A[1][1]*(int64_t)y) + (1LL<<ez) * b[1]);
+    int64_t mx  = m * (uint64_t)((A[0][0] * (int64_t)x + A[0][1]*(int64_t)y) + (1LL<<ez) * b[0]);
+    int64_t my  = m * (uint64_t)((A[1][0] * (int64_t)x + A[1][1]*(int64_t)y) + (1LL<<ez) * b[1]);
 
     block->u.mv[ref][0] = (mx + (1<<(ez+ep))) >> (ez+ep);
     block->u.mv[ref][1] = (my + (1<<(ez+ep))) >> (ez+ep);