status

can be used, still needs a (security) review.

intro

this package contains an ssh client, sftpfs and the library that
the client uses.  the goals are to let plan 9 & inferno users use
resources from another (unix) machine: interactive shell, file
server, and eventually network.  for the future, an ssh server is
planned.

install

first, make sure you have "util" installed.

change mkconfig if you do not have $ROOT set.  now "mk install" to
compile and install the files.

when building from within inferno, insert SYSHOST=Inferno and ROOT=
in the mk invocations to override the values in the mkconfig.

download

the latest version can be found at:

    http://www.ueber.net/code/r/ssh

licence & author

all files expect except ssh-rsa.b and ssh-dsa.b in
appl/cmd/auth/factotum/proto/ (which are derived from inferno) are
in the public domain.  this code has been written by mechiel lukkien,
reachable at mechiel@ueber.net or mechiel@xs4all.nl.

todo

• security problem:  i don't know how big (number of bits) the dh
  client side secret should be, and whether we should verify if it's
  correct/secure.
  

• factotum:  change proto=rsa & proto=dsa to not query user for keys if none matching.
        IO.findkeys() probably needs flag to not require a match:
        "keymanc <-= (attrs, 1, kc);     # TO DO: 1 => 0 for not needed"
  

• see if there is a race with newkeys. we probably should use our new keys after we send the newkeys message, and likewise for when the newkeys message from remote comes in.

• sshlib: check that dh param from server is valid/sane?
• sshlib: zero out sensitive data after use. can we do that with ipint too? and encryption algorithm state.
• think about sshnet
• sshlib: do auth keyboard-interactive? is there a generic challenge-response method in factotum?

• sftpfs: deal with case where sftp readdir does not return stat attributes? openssh sftp server is fine, others may not be.
• sftpfs: allow giving path for uid/gid -> name translation? needs care if that file is served by sftp.
• sftpfs: cache attrs for a short while? for styx stat after styx walk (for both we do an sftp stat). could help for create & remove too.
• sftpfs: read directories ahead, as optimisation?

• sshlib: make it faster. the expmod() calls for the dh exchange take up seconds. perhaps i use too many bits?
• sshlib: do rfc4419 "diffie-hellman-group-exchange-sha256". inferno first needs sha256 for that.

• sshlib: compression.  it's hard in inferno, because we have to flush the
  buffers for each packet (but keep compression state).  inferno's
  deflate filter doesn't support that.
  

• crypto: cast128-cbc, test/fix blowfish, sha256, ripemd160
• test IDEA?
• test against other sshd's than openssh (e.g. dropbear, lsh, more?)

docs

see doc/rfc.txt for the relevant rfc's and some excerpts from it.

sshpubkey turns the public part of key (from factotum, or as generated
by dsagen,rsagen) into a string you can put in an openssh
.ssh/authorized_keys.