From aeddb3607be94b1d6fef41b602b07f08223ea565 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Wed, 26 Jul 2017 20:10:28 +0200
Subject: [PATCH] avcodec/pixlet: Simplify nbits computation
Fixes multiple integer overflows
Fixes: runtime error: signed integer overflow: 1 + 2147483647 cannot be represented in type 'int'
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
libavcodec/pixlet.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/libavcodec/pixlet.c b/libavcodec/pixlet.c
index 0e541a9ccb4..a9661d3ab68 100644
--- a/libavcodec/pixlet.c
+++ b/libavcodec/pixlet.c
@@ -206,8 +206,8 @@ static int read_high_coeffs(AVCodecContext *avctx, uint8_t *src, int16_t *dst, i
if ((ret = init_get_bits8(b, src, bytestream2_get_bytes_left(&ctx->gb))) < 0)
return ret;
- if ((a >= 0) + (a ^ (a >> 31)) - (a >> 31) != 1) {
- nbits = 33 - ff_clz((a >= 0) + (a ^ (a >> 31)) - (a >> 31) - 1);
+ if (a ^ (a >> 31)) {
+ nbits = 33 - ff_clz(a ^ (a >> 31));
if (nbits > 16)
return AVERROR_INVALIDDATA;
} else {
--
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