mirror of
https://github.com/zeek/zeek.git
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Move adapter-specific code back into the adapter
This commit is contained in:
Tim Wojtulewicz
parent
1eed8b7f67
commit
b6ab22e9fb
4 changed files with 832 additions and 816 deletions
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@ -17,8 +17,9 @@
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#include "zeek/analyzer/protocol/tcp/events.bif.h"
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#include "zeek/analyzer/protocol/tcp/types.bif.h"
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static const int ORIG = 1;
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static const int RESP = 2;
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constexpr int ORIG = 1;
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constexpr int RESP = 2;
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constexpr int32_t TOO_LARGE_SEQ_DELTA = 1048576;
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using namespace zeek;
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using namespace zeek::packet_analysis::TCP;
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@ -79,6 +80,619 @@ void TCPSessionAdapter::Done()
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finished = 1;
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}
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static int get_segment_len(int payload_len, analyzer::tcp::TCP_Flags flags)
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{
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int seg_len = payload_len;
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if ( flags.SYN() )
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// SYN consumes a byte of sequence space.
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++seg_len;
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if ( flags.FIN() )
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// FIN consumes a bytes of sequence space.
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++seg_len;
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if ( flags.RST() )
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// Don't include the data in the computation of
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// the sequence space for this connection, as
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// it's not in fact part of the TCP stream.
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seg_len -= payload_len;
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return seg_len;
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}
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static void init_endpoint(analyzer::tcp::TCP_Endpoint* endpoint, analyzer::tcp::TCP_Flags flags,
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uint32_t first_seg_seq, uint32_t last_seq, double t)
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{
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switch ( endpoint->state ) {
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case analyzer::tcp::TCP_ENDPOINT_INACTIVE:
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if ( flags.SYN() )
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{
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endpoint->InitAckSeq(first_seg_seq);
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endpoint->InitStartSeq(first_seg_seq);
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}
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else
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{
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// This is a partial connection - set up the initial sequence
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// numbers as though we saw a SYN, to keep the relative byte
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// numbering consistent.
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endpoint->InitAckSeq(first_seg_seq - 1);
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endpoint->InitStartSeq(first_seg_seq - 1);
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// But ensure first packet is not marked duplicate
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last_seq = first_seg_seq;
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}
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endpoint->InitLastSeq(last_seq);
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endpoint->start_time = t;
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break;
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case analyzer::tcp::TCP_ENDPOINT_SYN_SENT:
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case analyzer::tcp::TCP_ENDPOINT_SYN_ACK_SENT:
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if ( flags.SYN() && first_seg_seq != endpoint->StartSeq() )
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{
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endpoint->Conn()->Weird("SYN_seq_jump");
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endpoint->InitStartSeq(first_seg_seq);
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endpoint->InitAckSeq(first_seg_seq);
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endpoint->InitLastSeq(last_seq);
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}
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break;
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case analyzer::tcp::TCP_ENDPOINT_ESTABLISHED:
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case analyzer::tcp::TCP_ENDPOINT_PARTIAL:
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if ( flags.SYN() )
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{
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if ( endpoint->Size() > 0 )
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endpoint->Conn()->Weird("SYN_inside_connection");
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if ( first_seg_seq != endpoint->StartSeq() )
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endpoint->Conn()->Weird("SYN_seq_jump");
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// Make a guess that somehow the connection didn't get established,
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// and this SYN will be the one that actually sets it up.
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endpoint->InitStartSeq(first_seg_seq);
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endpoint->InitAckSeq(first_seg_seq);
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endpoint->InitLastSeq(last_seq);
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}
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break;
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case analyzer::tcp::TCP_ENDPOINT_RESET:
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if ( flags.SYN() )
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{
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if ( endpoint->prev_state == analyzer::tcp::TCP_ENDPOINT_INACTIVE )
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{
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// Seq. numbers were initialized by a RST packet from this
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// endpoint, but now that a SYN is seen from it, that could mean
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// the earlier RST was spoofed/injected, so re-initialize. This
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// mostly just helps prevent misrepresentations of payload sizes
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// that are based on bad initial sequence values.
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endpoint->InitStartSeq(first_seg_seq);
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endpoint->InitAckSeq(first_seg_seq);
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endpoint->InitLastSeq(last_seq);
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}
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}
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break;
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default:
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break;
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}
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}
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static uint64_t get_relative_seq(const analyzer::tcp::TCP_Endpoint* endpoint,
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uint32_t cur_base, uint32_t last,
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uint32_t wraps, bool* underflow)
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{
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int32_t delta = seq_delta(cur_base, last);
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if ( delta < 0 )
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{
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if ( wraps && cur_base > last )
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// Seems to be a part of a previous 32-bit sequence space.
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--wraps;
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}
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else if ( delta > 0 )
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{
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if ( cur_base < last )
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// The sequence space wrapped around.
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++wraps;
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}
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if ( wraps == 0 )
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{
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delta = seq_delta(cur_base, endpoint->StartSeq());
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if ( underflow && delta < 0 )
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*underflow = true;
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return delta;
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}
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return endpoint->ToRelativeSeqSpace(cur_base, wraps);
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}
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static void update_history(analyzer::tcp::TCP_Flags flags,
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analyzer::tcp::TCP_Endpoint* endpoint,
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uint64_t rel_seq, int len)
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{
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int bits_set = (flags.SYN() ? 1 : 0) + (flags.FIN() ? 1 : 0) +
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(flags.RST() ? 1 : 0);
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if ( bits_set > 1 )
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{
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if ( flags.FIN() && flags.RST() )
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endpoint->CheckHistory(HIST_FIN_RST_PKT, 'I');
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else
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endpoint->CheckHistory(HIST_MULTI_FLAG_PKT, 'Q');
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}
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else if ( bits_set == 1 )
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{
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if ( flags.SYN() )
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{
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char code = flags.ACK() ? 'H' : 'S';
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if ( endpoint->CheckHistory(HIST_SYN_PKT, code) &&
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rel_seq != endpoint->hist_last_SYN )
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endpoint->AddHistory(code);
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endpoint->hist_last_SYN = rel_seq;
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}
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if ( flags.FIN() )
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{
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// For FIN's, the sequence number comes at the
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// end of (any data in) the packet, not the
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// beginning as for SYNs and RSTs.
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if ( endpoint->CheckHistory(HIST_FIN_PKT, 'F') &&
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rel_seq + len != endpoint->hist_last_FIN )
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endpoint->AddHistory('F');
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endpoint->hist_last_FIN = rel_seq + len;
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}
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if ( flags.RST() )
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{
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if ( endpoint->CheckHistory(HIST_RST_PKT, 'R') &&
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rel_seq != endpoint->hist_last_RST )
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endpoint->AddHistory('R');
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endpoint->hist_last_RST = rel_seq;
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}
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}
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else
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{ // bits_set == 0
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if ( len )
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endpoint->CheckHistory(HIST_DATA_PKT, 'D');
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else if ( flags.ACK() )
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endpoint->CheckHistory(HIST_ACK_PKT, 'A');
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}
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}
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static void update_window(analyzer::tcp::TCP_Endpoint* endpoint, unsigned int window,
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uint32_t base_seq, uint32_t ack_seq, analyzer::tcp::TCP_Flags flags)
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{
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// Note, applying scaling here would be incorrect for an initial SYN,
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// whose window value is always unscaled. However, we don't
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// check the window's value for recision in that case anyway, so
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// no-harm-no-foul.
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int scale = endpoint->window_scale;
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window = window << scale;
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// Zero windows are boring if either (1) they come with a RST packet
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// or after a RST packet, or (2) they come after the peer has sent
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// a FIN (because there's no relevant window at that point anyway).
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// (They're also boring if they come after the peer has sent a RST,
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// but *nothing* should be sent in response to a RST, so we ignore
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// that case.)
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//
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// However, they *are* potentially interesting if sent by an
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// endpoint that's already sent a FIN, since that FIN meant "I'm
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// not going to send any more", but doesn't mean "I won't receive
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// any more".
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if ( window == 0 && ! flags.RST() &&
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endpoint->peer->state != analyzer::tcp::TCP_ENDPOINT_CLOSED &&
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endpoint->state != analyzer::tcp::TCP_ENDPOINT_RESET )
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endpoint->ZeroWindow();
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// Don't analyze window values off of SYNs, they're sometimes
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// immediately rescinded. Also don't do so for FINs or RSTs,
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// or if the connection has already been partially closed, since
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// such recisions occur frequently in practice, probably as the
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// receiver loses buffer memory due to its process going away.
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if ( ! flags.SYN() && ! flags.FIN() && ! flags.RST() &&
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endpoint->state != analyzer::tcp::TCP_ENDPOINT_CLOSED &&
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endpoint->state != analyzer::tcp::TCP_ENDPOINT_RESET )
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{
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// ### Decide whether to accept new window based on Active
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// Mapping policy.
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if ( seq_delta(base_seq, endpoint->window_seq) >= 0 &&
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seq_delta(ack_seq, endpoint->window_ack_seq) >= 0 )
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{
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uint32_t new_edge = ack_seq + window;
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uint32_t old_edge = endpoint->window_ack_seq + endpoint->window;
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int32_t advance = seq_delta(new_edge, old_edge);
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if ( advance < 0 )
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{
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// An apparent window recision. Allow a
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// bit of slop for window scaling. This is
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// because sometimes there will be an
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// apparent recision due to the granularity
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// of the scaling.
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if ( (-advance) >= (1 << scale) )
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endpoint->Conn()->Weird("window_recision");
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}
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endpoint->window = window;
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endpoint->window_ack_seq = ack_seq;
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endpoint->window_seq = base_seq;
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}
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}
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}
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static zeek::RecordValPtr build_syn_packet_val(bool is_orig, const zeek::IP_Hdr* ip,
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const struct tcphdr* tcp)
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{
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int winscale = -1;
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int MSS = 0;
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int SACK = 0;
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// Parse TCP options.
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u_char* options = (u_char*) tcp + sizeof(struct tcphdr);
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u_char* opt_end = (u_char*) tcp + tcp->th_off * 4;
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while ( options < opt_end )
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{
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unsigned int opt = options[0];
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if ( opt == TCPOPT_EOL )
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// All done - could flag if more junk left over ....
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break;
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if ( opt == TCPOPT_NOP )
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{
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++options;
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continue;
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}
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if ( options + 1 >= opt_end )
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// We've run off the end, no room for the length.
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break;
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unsigned int opt_len = options[1];
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if ( options + opt_len > opt_end )
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// No room for rest of option.
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break;
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if ( opt_len == 0 )
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// Trashed length field.
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break;
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switch ( opt ) {
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case TCPOPT_SACK_PERMITTED:
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SACK = 1;
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break;
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case TCPOPT_MAXSEG:
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if ( opt_len < 4 )
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break; // bad length
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MSS = (options[2] << 8) | options[3];
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break;
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case 3: // TCPOPT_WSCALE
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if ( opt_len < 3 )
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break; // bad length
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winscale = options[2];
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break;
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default: // just skip over
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break;
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}
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options += opt_len;
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}
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static auto SYN_packet = zeek::id::find_type<zeek::RecordType>("SYN_packet");
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auto v = zeek::make_intrusive<zeek::RecordVal>(SYN_packet);
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v->Assign(0, is_orig);
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v->Assign(1, static_cast<bool>(ip->DF()));
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v->Assign(2, ip->TTL());
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v->Assign(3, ip->TotalLen());
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v->Assign(4, ntohs(tcp->th_win));
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v->Assign(5, winscale);
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v->Assign(6, MSS);
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v->Assign(7, static_cast<bool>(SACK));
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return v;
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}
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static void init_window(analyzer::tcp::TCP_Endpoint* endpoint, analyzer::tcp::TCP_Endpoint* peer,
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analyzer::tcp::TCP_Flags flags, bro_int_t scale, uint32_t base_seq,
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uint32_t ack_seq)
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{
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// ### In the following, we could be fooled by an
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// inconsistent SYN retransmission. Where's a normalizer
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// when you need one?
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if ( scale < 0 )
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{ // no window scaling option
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if ( flags.ACK() )
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{ // window scaling not negotiated
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endpoint->window_scale = 0;
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peer->window_scale = 0;
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}
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else
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// We're not offering window scaling.
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// Ideally, we'd remember this fact so that
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// if the SYN/ACK *does* include window
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// scaling, we know it won't be negotiated.
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// But it's a pain to track that, and hard
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// to see how an adversarial responder could
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// use it to evade. Also, if we *do* want
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// to track it, we could do so using
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// connection_SYN_packet.
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endpoint->window_scale = 0;
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}
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else
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{
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endpoint->window_scale = scale;
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endpoint->window_seq = base_seq;
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endpoint->window_ack_seq = ack_seq;
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peer->window_seq = ack_seq;
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peer->window_ack_seq = base_seq;
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}
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}
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static void init_peer(analyzer::tcp::TCP_Endpoint* peer, analyzer::tcp::TCP_Endpoint* endpoint,
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analyzer::tcp::TCP_Flags flags, uint32_t ack_seq)
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{
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if ( ! flags.SYN() && ! flags.FIN() && ! flags.RST() )
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{
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if ( endpoint->state == analyzer::tcp::TCP_ENDPOINT_SYN_SENT ||
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endpoint->state == analyzer::tcp::TCP_ENDPOINT_SYN_ACK_SENT ||
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endpoint->state == analyzer::tcp::TCP_ENDPOINT_ESTABLISHED )
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{
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// We've already sent a SYN, but that
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// hasn't roused the other end, yet we're
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// ack'ing their data.
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if ( ! endpoint->Conn()->DidWeird() )
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endpoint->Conn()->Weird("possible_split_routing");
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}
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}
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// Start the sequence numbering as if there was an initial
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// SYN, so the relative numbering of subsequent data packets
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// stays consistent.
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peer->InitStartSeq(ack_seq - 1);
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peer->InitAckSeq(ack_seq - 1);
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peer->InitLastSeq(ack_seq - 1);
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}
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static void update_ack_seq(analyzer::tcp::TCP_Endpoint* endpoint, uint32_t ack_seq)
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{
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int32_t delta_ack = seq_delta(ack_seq, endpoint->AckSeq());
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if ( ack_seq == 0 && delta_ack > TOO_LARGE_SEQ_DELTA )
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// More likely that this is a broken ack than a
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// large connection that happens to land on 0 in the
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// sequence space.
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;
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else if ( delta_ack > 0 )
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endpoint->UpdateAckSeq(ack_seq);
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}
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// Returns the difference between last_seq and the last sequence
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// seen by the endpoint (may be negative).
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static int32_t update_last_seq(analyzer::tcp::TCP_Endpoint* endpoint, uint32_t last_seq,
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analyzer::tcp::TCP_Flags flags, int len)
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{
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int32_t delta_last = seq_delta(last_seq, endpoint->LastSeq());
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if ( (flags.SYN() || flags.RST()) &&
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(delta_last > TOO_LARGE_SEQ_DELTA ||
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delta_last < -TOO_LARGE_SEQ_DELTA) )
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// ### perhaps trust RST seq #'s if initial and not too
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// outlandish, but not if they're coming after the other
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// side has sent a FIN - trust the FIN ack instead
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;
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else if ( flags.FIN() &&
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endpoint->LastSeq() == endpoint->StartSeq() + 1 )
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// Update last_seq based on the FIN even if delta_last < 0.
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// This is to accommodate > 2 GB connections for which
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// we've only seen the SYN and the FIN (hence the check
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// for last_seq == start_seq + 1).
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endpoint->UpdateLastSeq(last_seq);
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else if ( endpoint->state == analyzer::tcp::TCP_ENDPOINT_RESET )
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// don't trust any subsequent sequence numbers
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;
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else if ( delta_last > 0 )
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// ### check for large jumps here.
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// ## endpoint->last_seq = last_seq;
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endpoint->UpdateLastSeq(last_seq);
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else if ( delta_last <= 0 && len > 0 )
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endpoint->DidRxmit();
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return delta_last;
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}
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void TCPSessionAdapter::Process(bool is_orig, const struct tcphdr* tp, int len,
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const std::unique_ptr<IP_Hdr>& ip,
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const u_char* data, int remaining)
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{
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analyzer::tcp::TCP_Flags flags(tp);
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uint32_t base_seq = ntohl(tp->th_seq);
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uint32_t ack_seq = ntohl(tp->th_ack);
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uint32_t tcp_hdr_len = data - (const u_char*) tp;
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analyzer::tcp::TCP_Endpoint* endpoint = is_orig ? orig : resp;
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analyzer::tcp::TCP_Endpoint* peer = endpoint->peer;
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SetPartialStatus(flags, endpoint->IsOrig());
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int seg_len = get_segment_len(len, flags);
|
||||
uint32_t seq_one_past_segment = base_seq + seg_len;
|
||||
|
||||
init_endpoint(endpoint, flags, base_seq, seq_one_past_segment,
|
||||
run_state::current_timestamp);
|
||||
|
||||
bool seq_underflow = false;
|
||||
uint64_t rel_seq = get_relative_seq(endpoint, base_seq, endpoint->LastSeq(),
|
||||
endpoint->SeqWraps(), &seq_underflow);
|
||||
|
||||
if ( seq_underflow && ! flags.RST() )
|
||||
// Can't tell if if this is a retransmit/out-of-order or something
|
||||
// before the sequence Bro initialized the endpoint at or the TCP is
|
||||
// just broken and sending garbage sequences. In either case, some
|
||||
// standard analysis doesn't apply (e.g. reassembly).
|
||||
Weird("TCP_seq_underflow_or_misorder");
|
||||
|
||||
update_history(flags, endpoint, rel_seq, len);
|
||||
update_window(endpoint, ntohs(tp->th_win), base_seq, ack_seq, flags);
|
||||
|
||||
if ( ! orig->did_close || ! resp->did_close )
|
||||
Conn()->SetLastTime(run_state::current_timestamp);
|
||||
|
||||
if ( flags.SYN() )
|
||||
{
|
||||
SynWeirds(flags, endpoint, len);
|
||||
RecordValPtr SYN_vals = build_syn_packet_val(is_orig, ip.get(), tp);
|
||||
init_window(endpoint, peer, flags, SYN_vals->GetFieldAs<IntVal>(5),
|
||||
base_seq, ack_seq);
|
||||
|
||||
if ( connection_SYN_packet )
|
||||
EnqueueConnEvent(connection_SYN_packet, ConnVal(), SYN_vals);
|
||||
}
|
||||
|
||||
if ( flags.FIN() )
|
||||
{
|
||||
++endpoint->FIN_cnt;
|
||||
|
||||
if ( endpoint->FIN_cnt >= detail::tcp_storm_thresh && run_state::current_timestamp <
|
||||
endpoint->last_time + detail::tcp_storm_interarrival_thresh )
|
||||
Weird("FIN_storm");
|
||||
|
||||
endpoint->FIN_seq = rel_seq + seg_len;
|
||||
}
|
||||
|
||||
if ( flags.RST() )
|
||||
{
|
||||
++endpoint->RST_cnt;
|
||||
|
||||
if ( endpoint->RST_cnt >= detail::tcp_storm_thresh && run_state::current_timestamp <
|
||||
endpoint->last_time + detail::tcp_storm_interarrival_thresh )
|
||||
Weird("RST_storm");
|
||||
|
||||
// This now happens often enough that it's
|
||||
// not in the least interesting.
|
||||
//if ( len > 0 )
|
||||
// Weird("RST_with_data");
|
||||
|
||||
PacketWithRST();
|
||||
}
|
||||
|
||||
uint64_t rel_ack = 0;
|
||||
|
||||
if ( flags.ACK() )
|
||||
{
|
||||
if ( is_orig && ! seen_first_ACK &&
|
||||
(endpoint->state == analyzer::tcp::TCP_ENDPOINT_ESTABLISHED ||
|
||||
endpoint->state == analyzer::tcp::TCP_ENDPOINT_SYN_SENT) )
|
||||
{
|
||||
seen_first_ACK = 1;
|
||||
Event(connection_first_ACK);
|
||||
}
|
||||
|
||||
if ( peer->state == analyzer::tcp::TCP_ENDPOINT_INACTIVE )
|
||||
{
|
||||
rel_ack = 1;
|
||||
init_peer(peer, endpoint, flags, ack_seq);
|
||||
}
|
||||
else
|
||||
{
|
||||
bool ack_underflow = false;
|
||||
rel_ack = get_relative_seq(peer, ack_seq, peer->AckSeq(),
|
||||
peer->AckWraps(), &ack_underflow);
|
||||
|
||||
if ( ack_underflow )
|
||||
{
|
||||
rel_ack = 0;
|
||||
Weird("TCP_ack_underflow_or_misorder");
|
||||
}
|
||||
else if ( ! flags.RST() )
|
||||
// Don't trust ack's in RST packets.
|
||||
update_ack_seq(peer, ack_seq);
|
||||
}
|
||||
}
|
||||
|
||||
int32_t delta_last = update_last_seq(endpoint, seq_one_past_segment, flags, len);
|
||||
endpoint->last_time = run_state::current_timestamp;
|
||||
|
||||
bool do_close;
|
||||
bool gen_event;
|
||||
UpdateStateMachine(run_state::current_timestamp, endpoint, peer, base_seq, ack_seq,
|
||||
len, delta_last, is_orig, flags, do_close, gen_event);
|
||||
|
||||
if ( flags.ACK() )
|
||||
// We wait on doing this until we've updated the state
|
||||
// machine so that if the ack reveals a content gap,
|
||||
// we can tell whether it came at the very end of the
|
||||
// connection (in a FIN or RST). Those gaps aren't
|
||||
// reliable - especially those for RSTs - and we refrain
|
||||
// from flagging them in the connection history.
|
||||
peer->AckReceived(rel_ack);
|
||||
|
||||
if ( tcp_packet )
|
||||
GeneratePacketEvent(rel_seq, rel_ack, data, len, remaining, is_orig, flags);
|
||||
|
||||
if ( (tcp_option || tcp_options) && tcp_hdr_len > sizeof(*tp) )
|
||||
ParseTCPOptions(tp, is_orig);
|
||||
|
||||
// PIA/signature matching state needs to be initialized before
|
||||
// processing/reassembling any TCP data, since that processing may
|
||||
// itself try to perform signature matching. Also note that a SYN
|
||||
// packet may technically carry data (see RFC793 Section 3.4 and also
|
||||
// TCP Fast Open).
|
||||
CheckPIA_FirstPacket(is_orig, ip.get());
|
||||
|
||||
if ( DEBUG_tcp_data_sent )
|
||||
{
|
||||
DEBUG_MSG("%.6f before DataSent: len=%d remaining=%d skip=%d\n",
|
||||
run_state::network_time, len, remaining, Skipping());
|
||||
}
|
||||
|
||||
rel_data_seq = flags.SYN() ? rel_seq + 1 : rel_seq;
|
||||
|
||||
bool need_contents = false;
|
||||
if ( len > 0 && (remaining >= len || ! packet_children.empty()) &&
|
||||
! flags.RST() && ! Skipping() && ! seq_underflow )
|
||||
need_contents = endpoint->DataSent(run_state::current_timestamp, rel_data_seq,
|
||||
len, remaining, data, ip.get(), tp);
|
||||
|
||||
endpoint->CheckEOF();
|
||||
|
||||
if ( do_close )
|
||||
{
|
||||
// We need to postpone doing this until after we process
|
||||
// DataSent, so we don't generate a connection_finished event
|
||||
// until after data perhaps included with the FIN is processed.
|
||||
ConnectionClosed(endpoint, peer, gen_event);
|
||||
}
|
||||
|
||||
CheckRecording(need_contents, flags);
|
||||
}
|
||||
|
||||
analyzer::Analyzer* TCPSessionAdapter::FindChild(analyzer::ID arg_id)
|
||||
{
|
||||
analyzer::Analyzer* child = packet_analysis::IP::SessionAdapter::FindChild(arg_id);
|
||||
|
|
@ -1008,7 +1622,7 @@ void TCPSessionAdapter::AddExtraAnalyzers(Connection* conn)
|
|||
{
|
||||
static auto tcp_content_delivery_ports_orig = id::find_val<TableVal>("tcp_content_delivery_ports_orig");
|
||||
static auto tcp_content_delivery_ports_resp = id::find_val<TableVal>("tcp_content_delivery_ports_resp");
|
||||
const auto& dport = val_mgr->Port(ntohs(conn->RespPort()), TRANSPORT_TCP);
|
||||
const auto& dport = val_mgr->Port(ntohs(Conn()->RespPort()), TRANSPORT_TCP);
|
||||
|
||||
if ( ! reass )
|
||||
reass = (bool)tcp_content_delivery_ports_orig->FindOrDefault(dport);
|
||||
|
|
@ -1027,11 +1641,11 @@ void TCPSessionAdapter::AddExtraAnalyzers(Connection* conn)
|
|||
// handle non-reassembled data, it doesn't really fit into
|
||||
// our general framing ... Better would be to turn it
|
||||
// on *after* we discover we have interactive traffic.
|
||||
uint16_t resp_port = ntohs(conn->RespPort());
|
||||
uint16_t resp_port = ntohs(Conn()->RespPort());
|
||||
if ( resp_port == 22 || resp_port == 23 || resp_port == 513 )
|
||||
{
|
||||
static auto stp_skip_src = id::find_val<TableVal>("stp_skip_src");
|
||||
auto src = make_intrusive<AddrVal>(conn->OrigAddr());
|
||||
auto src = make_intrusive<AddrVal>(Conn()->OrigAddr());
|
||||
|
||||
if ( ! stp_skip_src->FindOrDefault(src) )
|
||||
AddChildAnalyzer(new analyzer::stepping_stone::SteppingStone_Analyzer(conn), false);
|
||||
|
|
@ -1047,3 +1661,199 @@ void TCPSessionAdapter::AddExtraAnalyzers(Connection* conn)
|
|||
// Add ConnSize analyzer. Needs to see packets, not stream.
|
||||
AddChildPacketAnalyzer(new analyzer::conn_size::ConnSize_Analyzer(conn));
|
||||
}
|
||||
|
||||
void TCPSessionAdapter::SynWeirds(analyzer::tcp::TCP_Flags flags,
|
||||
analyzer::tcp::TCP_Endpoint* endpoint,
|
||||
int data_len) const
|
||||
{
|
||||
if ( flags.RST() )
|
||||
endpoint->Conn()->Weird("TCP_christmas", "", GetAnalyzerName());
|
||||
|
||||
if ( flags.URG() )
|
||||
endpoint->Conn()->Weird("baroque_SYN", "", GetAnalyzerName());
|
||||
|
||||
if ( data_len > 0 )
|
||||
// Not technically wrong according to RFC 793, but the other side
|
||||
// would be forced to buffer data until the handshake succeeds, and
|
||||
// that could be bad in some cases, e.g. SYN floods.
|
||||
// T/TCP definitely complicates this.
|
||||
endpoint->Conn()->Weird("SYN_with_data", "", GetAnalyzerName());
|
||||
}
|
||||
|
||||
int TCPSessionAdapter::ParseTCPOptions(const struct tcphdr* tcp, bool is_orig)
|
||||
{
|
||||
// Parse TCP options.
|
||||
const u_char* options = (const u_char*) tcp + sizeof(struct tcphdr);
|
||||
const u_char* opt_end = (const u_char*) tcp + tcp->th_off * 4;
|
||||
std::vector<const u_char*> opts;
|
||||
|
||||
while ( options < opt_end )
|
||||
{
|
||||
unsigned int opt = options[0];
|
||||
|
||||
unsigned int opt_len;
|
||||
|
||||
if ( opt < 2 )
|
||||
opt_len = 1;
|
||||
|
||||
else if ( options + 1 >= opt_end )
|
||||
// We've run off the end, no room for the length.
|
||||
break;
|
||||
|
||||
else
|
||||
opt_len = options[1];
|
||||
|
||||
if ( opt_len == 0 )
|
||||
break; // trashed length field
|
||||
|
||||
if ( options + opt_len > opt_end )
|
||||
// No room for rest of option.
|
||||
break;
|
||||
|
||||
opts.emplace_back(options);
|
||||
options += opt_len;
|
||||
|
||||
if ( opt == TCPOPT_EOL )
|
||||
// All done - could flag if more junk left over ....
|
||||
break;
|
||||
}
|
||||
|
||||
if ( tcp_option )
|
||||
for ( const auto& o : opts )
|
||||
{
|
||||
auto kind = o[0];
|
||||
auto length = kind < 2 ? 1 : o[1];
|
||||
EnqueueConnEvent(tcp_option,
|
||||
ConnVal(),
|
||||
val_mgr->Bool(is_orig),
|
||||
val_mgr->Count(kind),
|
||||
val_mgr->Count(length));
|
||||
}
|
||||
|
||||
if ( tcp_options )
|
||||
{
|
||||
auto option_list = make_intrusive<VectorVal>(BifType::Vector::TCP::OptionList);
|
||||
|
||||
auto add_option_data = [](const RecordValPtr& rv, const u_char* odata, int olen)
|
||||
{
|
||||
if ( olen <= 2 )
|
||||
return;
|
||||
|
||||
auto data_len = olen - 2;
|
||||
auto data = reinterpret_cast<const char*>(odata + 2);
|
||||
rv->Assign(2, make_intrusive<StringVal>(data_len, data));
|
||||
};
|
||||
|
||||
for ( const auto& o : opts )
|
||||
{
|
||||
auto kind = o[0];
|
||||
auto length = kind < 2 ? 1 : o[1];
|
||||
auto option_record = make_intrusive<RecordVal>(BifType::Record::TCP::Option);
|
||||
option_list->Assign(option_list->Size(), option_record);
|
||||
option_record->Assign(0, kind);
|
||||
option_record->Assign(1, length);
|
||||
|
||||
switch ( kind ) {
|
||||
case 2:
|
||||
// MSS
|
||||
if ( length == 4 )
|
||||
{
|
||||
auto mss = ntohs(*reinterpret_cast<const uint16_t*>(o + 2));
|
||||
option_record->Assign(3, mss);
|
||||
}
|
||||
else
|
||||
{
|
||||
add_option_data(option_record, o, length);
|
||||
Weird("tcp_option_mss_invalid_len", util::fmt("%d", length));
|
||||
}
|
||||
break;
|
||||
|
||||
case 3:
|
||||
// window scale
|
||||
if ( length == 3 )
|
||||
{
|
||||
auto scale = o[2];
|
||||
option_record->Assign(4, scale);
|
||||
}
|
||||
else
|
||||
{
|
||||
add_option_data(option_record, o, length);
|
||||
Weird("tcp_option_window_scale_invalid_len", util::fmt("%d", length));
|
||||
}
|
||||
break;
|
||||
|
||||
case 4:
|
||||
// sack permitted (implicit boolean)
|
||||
if ( length != 2 )
|
||||
{
|
||||
add_option_data(option_record, o, length);
|
||||
Weird("tcp_option_sack_invalid_len", util::fmt("%d", length));
|
||||
}
|
||||
break;
|
||||
|
||||
case 5:
|
||||
// SACK blocks (1-4 pairs of 32-bit begin+end pointers)
|
||||
if ( length == 10 || length == 18 ||
|
||||
length == 26 || length == 34 )
|
||||
{
|
||||
auto p = reinterpret_cast<const uint32_t*>(o + 2);
|
||||
auto num_pointers = (length - 2) / 4;
|
||||
auto vt = id::index_vec;
|
||||
auto sack = make_intrusive<VectorVal>(std::move(vt));
|
||||
|
||||
for ( auto i = 0; i < num_pointers; ++i )
|
||||
sack->Assign(sack->Size(), val_mgr->Count(ntohl(p[i])));
|
||||
|
||||
option_record->Assign(5, sack);
|
||||
}
|
||||
else
|
||||
{
|
||||
add_option_data(option_record, o, length);
|
||||
Weird("tcp_option_sack_blocks_invalid_len", util::fmt("%d", length));
|
||||
}
|
||||
break;
|
||||
|
||||
case 8:
|
||||
// timestamps
|
||||
if ( length == 10 )
|
||||
{
|
||||
auto send = ntohl(*reinterpret_cast<const uint32_t*>(o + 2));
|
||||
auto echo = ntohl(*reinterpret_cast<const uint32_t*>(o + 6));
|
||||
option_record->Assign(6, send);
|
||||
option_record->Assign(7, echo);
|
||||
}
|
||||
else
|
||||
{
|
||||
add_option_data(option_record, o, length);
|
||||
Weird("tcp_option_timestamps_invalid_len", util::fmt("%d", length));
|
||||
}
|
||||
break;
|
||||
|
||||
default:
|
||||
add_option_data(option_record, o, length);
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
EnqueueConnEvent(tcp_options,
|
||||
ConnVal(),
|
||||
val_mgr->Bool(is_orig),
|
||||
std::move(option_list));
|
||||
}
|
||||
|
||||
if ( options < opt_end )
|
||||
return -1;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
void TCPSessionAdapter::CheckRecording(bool need_contents, analyzer::tcp::TCP_Flags flags)
|
||||
{
|
||||
bool record_current_content = need_contents || Conn()->RecordContents();
|
||||
bool record_current_packet =
|
||||
Conn()->RecordPackets() ||
|
||||
flags.SYN() || flags.FIN() || flags.RST();
|
||||
|
||||
Conn()->SetRecordCurrentContent(record_current_content);
|
||||
Conn()->SetRecordCurrentPacket(record_current_packet);
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue