From aeddb3607be94b1d6fef41b602b07f08223ea565 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer 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 Signed-off-by: Michael Niedermayer --- libavcodec/pixlet.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libavcodec/pixlet.c b/libavcodec/pixlet.c index 0e541a9ccb..a9661d3ab6 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 { -- GitLab