From 13c542795e24c943114dd802258de1d5595cd124 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Wed, 2 Sep 2020 22:42:05 +0200
Subject: [PATCH] avcodec/vc1_block: Fix integer overflow in ac value
Fixes: signed integer overflow: 25488 * 87381 cannot be represented in type 'int'
Fixes: 24765/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1_fuzzer-5108259565076480
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 3056e19e68122b9464b24870488f8faca4e78ea8)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
libavcodec/vc1_block.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c
index 976d330935..f87f664a2e 100644
--- a/libavcodec/vc1_block.c
+++ b/libavcodec/vc1_block.c
@@ -1056,7 +1056,7 @@ static int vc1_decode_intra_block(VC1Context *v, int16_t block[64], int n,
if (q1 < 1)
return AVERROR_INVALIDDATA;
for (k = 1; k < 8; k++)
- ac_val2[k] = (ac_val2[k] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
+ ac_val2[k] = (int)(ac_val2[k] * (unsigned)q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
}
}
} else { // top
@@ -1068,7 +1068,7 @@ static int vc1_decode_intra_block(VC1Context *v, int16_t block[64], int n,
if (q1 < 1)
return AVERROR_INVALIDDATA;
for (k = 1; k < 8; k++)
- ac_val2[k + 8] = (ac_val2[k + 8] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
+ ac_val2[k + 8] = (int)(ac_val2[k + 8] * (unsigned)q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18;
}
}
}