From 69636b443c4f40286135ad9658b5d44a9de4f3a4 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Fri, 10 Jul 2020 15:12:26 +0200 Subject: [PATCH] avcodec/golomb: Prevent shift by negative number This happened in get_ue_golomb() if the cached bitstream reader was in use, because there was no check to handle the case of the read value not being in the supported range. For consistency with the uncached bitstream reader and for compliance with the documentation, every value not in the 0-8190 range is treated as error although the cached bitstream reader could actually read values in the range 0..65534 without problems. Reviewed-by: Michael Niedermayer Signed-off-by: Andreas Rheinhardt --- libavcodec/golomb.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/libavcodec/golomb.h b/libavcodec/golomb.h index 1f988d74aa..aed9b22471 100644 --- a/libavcodec/golomb.h +++ b/libavcodec/golomb.h @@ -66,9 +66,12 @@ static inline int get_ue_golomb(GetBitContext *gb) return ff_ue_golomb_vlc_code[buf]; } else { int log = 2 * av_log2(buf) - 31; + + skip_bits_long(gb, 32 - log); + if (log < 7) + return AVERROR_INVALIDDATA; buf >>= log; buf--; - skip_bits_long(gb, 32 - log); return buf; }