1This is a harness to help with fuzzing KEX.
2
3To use it, you first set it to count packets in each direction:
4
5./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key -c
6S2C: 29
7C2S: 31
8
9Then get it to record a particular packet (in this case the 4th
10packet from client->server):
11
12./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key \
13    -d -D C2S -i 3 -f packet_3
14
15Fuzz the packet somehow:
16
17dd if=/dev/urandom of=packet_3 bs=32 count=1 # Just for example
18
19Then re-run the key exchange substituting the modified packet in
20its original sequence:
21
22./kexfuzz -K diffie-hellman-group1-sha1 -k host_ed25519_key \
23    -r -D C2S -i 3 -f packet_3
24
25A comprehensive KEX fuzz run would fuzz every packet in both
26directions for each key exchange type and every hostkey type.
27This will take some time.
28
29Limitations: kexfuzz can't change the ordering of packets at
30present. It is limited to replacing individual packets with
31fuzzed variants with the same type. It really should allow
32insertion, deletion on replacement of packets too.
33
34$OpenBSD: README,v 1.3 2017/10/20 02:13:41 djm Exp $
35