From b0207c5b2a82cc9a7c80640977a004053e2d6ecf Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 17 May 2018 13:40:38 +0200 Subject: [PATCH] indeo4: Decode all or nothing of a band header. This avoids inconsistent value combinations. Alternatively it would be possible to add more checks and careful use of temporary variables, but my try of this quickly seemed to become a rather large change. The disadvantage of this, is that the struct is copied back and forth. Fixes: index 6 out of bounds for type 'const uint16_t [5][16]' Fixes: 6557/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_INDEO4_fuzzer-4787296550256640 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 10c8521265da86118597336c5589e26de377a374) Signed-off-by: Michael Niedermayer --- libavcodec/indeo4.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/libavcodec/indeo4.c b/libavcodec/indeo4.c index 85d5fa3e7a..5809052cf8 100644 --- a/libavcodec/indeo4.c +++ b/libavcodec/indeo4.c @@ -260,12 +260,14 @@ static int decode_pic_hdr(IVI45DecContext *ctx, AVCodecContext *avctx) * @param[in] avctx pointer to the AVCodecContext * @return result code: 0 = OK, negative number = error */ -static int decode_band_hdr(IVI45DecContext *ctx, IVIBandDesc *band, +static int decode_band_hdr(IVI45DecContext *ctx, IVIBandDesc *arg_band, AVCodecContext *avctx) { int plane, band_num, indx, transform_id, scan_indx; int i; int quant_mat; + IVIBandDesc temp_band, *band = &temp_band; + memcpy(&temp_band, arg_band, sizeof(temp_band)); plane = get_bits(&ctx->gb, 2); band_num = get_bits(&ctx->gb, 4); @@ -395,10 +397,10 @@ static int decode_band_hdr(IVI45DecContext *ctx, IVIBandDesc *band, /* decode block huffman codebook */ if (!get_bits1(&ctx->gb)) - band->blk_vlc.tab = ctx->blk_vlc.tab; + arg_band->blk_vlc.tab = ctx->blk_vlc.tab; else if (ff_ivi_dec_huff_desc(&ctx->gb, 1, IVI_BLK_HUFF, - &band->blk_vlc, avctx)) + &arg_band->blk_vlc, avctx)) return AVERROR_INVALIDDATA; /* select appropriate rvmap table for this band */ @@ -439,6 +441,9 @@ static int decode_band_hdr(IVI45DecContext *ctx, IVIBandDesc *band, return AVERROR_INVALIDDATA; } + band->blk_vlc = arg_band->blk_vlc; + memcpy(arg_band, band, sizeof(*arg_band)); + return 0; }