From f5ce67d837cd686f12c515e601acd6e2a5df05a7 Mon Sep 17 00:00:00 2001 From: Alex Converse Date: Thu, 9 Feb 2012 20:21:47 -0800 Subject: [PATCH] svq3: Prevent illegal reads while parsing extradata. Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind (cherry picked from commit 9e1db721c4329f4ac166a0bcc002c8d75f831aba) Signed-off-by: Reinhard Tartler --- libavcodec/svq3.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/libavcodec/svq3.c b/libavcodec/svq3.c index 09d598c044..662d74d6fb 100644 --- a/libavcodec/svq3.c +++ b/libavcodec/svq3.c @@ -809,7 +809,9 @@ static av_cold int svq3_decode_init(AVCodecContext *avctx) MpegEncContext *s = &h->s; int m; unsigned char *extradata; + unsigned char *extradata_end; unsigned int size; + int marker_found = 0; if (ff_h264_decode_init(avctx) < 0) return -1; @@ -829,19 +831,26 @@ static av_cold int svq3_decode_init(AVCodecContext *avctx) /* prowl for the "SEQH" marker in the extradata */ extradata = (unsigned char *)avctx->extradata; - for (m = 0; m < avctx->extradata_size; m++) { - if (!memcmp(extradata, "SEQH", 4)) - break; - extradata++; + extradata_end = avctx->extradata + avctx->extradata_size; + if (extradata) { + for (m = 0; m + 8 < avctx->extradata_size; m++) { + if (!memcmp(extradata, "SEQH", 4)) { + marker_found = 1; + break; + } + extradata++; + } } /* if a match was found, parse the extra data */ - if (extradata && !memcmp(extradata, "SEQH", 4)) { + if (marker_found) { GetBitContext gb; int frame_size_code; size = AV_RB32(&extradata[4]); + if (size > extradata_end - extradata - 8) + return AVERROR_INVALIDDATA; init_get_bits(&gb, extradata + 8, size*8); /* 'frame size code' and optional 'width, height' */