From: Michael Niedermayer <[email protected]> When receiving fragmented packets, the first packet declares the size, and the later ones normally are small follow-on packets that don't repeat the size and the other header fields. But technically, the later fragments also can have a full header, declaring a different size than the previous packet.
If the follow-on packet declares a larger size than the initial one, we could end up writing outside of the allocation. This fixes out of bounds writes. Found-by: Paul Cher <[email protected]> Reviewed-by: Paul Cher <[email protected]> CC: [email protected] --- Now with error return and improved commit message. --- libavformat/rtmppkt.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/libavformat/rtmppkt.c b/libavformat/rtmppkt.c index f8c51d0..1cb3078 100644 --- a/libavformat/rtmppkt.c +++ b/libavformat/rtmppkt.c @@ -235,6 +235,14 @@ static int rtmp_packet_read_one_chunk(URLContext *h, RTMPPacket *p, if (hdr != RTMP_PS_TWELVEBYTES) timestamp += prev_pkt[channel_id].timestamp; + if (prev_pkt[channel_id].read && size != prev_pkt[channel_id].size) { + av_log(h, AV_LOG_ERROR, "RTMP packet size mismatch %d != %d\n", + size, prev_pkt[channel_id].size); + ff_rtmp_packet_destroy(&prev_pkt[channel_id]); + prev_pkt[channel_id].read = 0; + return AVERROR_INVALIDDATA; + } + if (!prev_pkt[channel_id].read) { if ((ret = ff_rtmp_packet_create(p, channel_id, type, timestamp, size)) < 0) -- 2.10.1 (Apple Git-78) _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
