From 174ec7d744d3e45bdb74c4c568f7bc5f689d4304 Mon Sep 17 00:00:00 2001 From: Andreas Cadhalpun Date: Sat, 19 Dec 2015 12:02:56 +0100 Subject: [PATCH] nutdec: reject negative value_len in read_sm_data If it is negative, it can cause the byte position to move backwards in avio_skip, which in turn makes sm_size negative and thus size larger than the size of the packet buffer, causing invalid writes in avio_read. Also fix potential overflow of avio_tell(bc) + value_len. Reviewed-by: Michael Niedermayer Signed-off-by: Andreas Cadhalpun (cherry picked from commit ce10f572c12b0d172c72d31d8c979afce602bf0c) Signed-off-by: Andreas Cadhalpun --- libavformat/nutdec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavformat/nutdec.c b/libavformat/nutdec.c index 201c34e0e9..bfa2bade27 100644 --- a/libavformat/nutdec.c +++ b/libavformat/nutdec.c @@ -927,7 +927,7 @@ static int read_sm_data(AVFormatContext *s, AVIOContext *bc, AVPacket *pkt, int return ret; } value_len = ffio_read_varlen(bc); - if (avio_tell(bc) + value_len >= maxpos) + if (value_len < 0 || value_len >= maxpos - avio_tell(bc)) return AVERROR_INVALIDDATA; if (!strcmp(name, "Palette")) { dst = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, value_len);