Some distributions already have OpenSSH 9.8, which introduces split
sshd/sshd-session binaries, and there we need to copy the binary from
the host, which can be /usr/libexec/openssh/sshd-session (Fedora
Rawhide), /usr/lib/ssh/sshd-session (Arch Linux),
/usr/lib/openssh/sshd-session (Debian), and possibly other paths.

Add at least those three, and, if we don't find sshd-session, assume
we don't need it: it could very well be an older version of OpenSSH,
as reported by David for Fedora 40, or perhaps another daemon (would
Dropbear even work? I'm not sure).

Reported-by: David Gibson <david@gibson.dropbear.id.au>
Fixes: d6817b3930be ("test/passt.mbuto: Install sshd-session OpenSSH's split process")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>

OpenSSH now ships a per-session binary, sshd-session, with sshd
acting as mere listener. It's typically not found in $PATH, so specify
the whole path at which it's commonly installed in $PROGS.

Link: https://www.openssh.com/releasenotes.html#9.8p1
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

...OpenSSH >= 9.8 otherwise complains that:

  sshd requires execution with an absolute path

Link: https://bugs.gentoo.org/936041
Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1078429
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

During some debugging recently, I wanted to extact a file from a test
guest and found it was tricky, since the ssh-over-vsock setup we had didn't
allow sftp/scp.  We can fix this by adding a line to the guest side sshd
config from mbuto.  While we're there correct an inaccurate comment.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

f0ccca74 ("test: make passt.mbuto script more robust") is supposed to make
mbuto more robust by standardizing on always putting things in /usr/sbin
with /sbin a symlink to it.  This matters because different distros have
different conventions about how the two are used.

However, the logic there requires that /usr/sbin at least exists to start
with.  This isn't always the case with Fedora derived mbuto images.
Ironically the DIRS variable ensures that /sbin exists, although we then
remove it, but doesn't require /usr/sbin to exist.  Fix that up so that
the new logic will work with Fedora.

Fixes: f0ccca741f64 ("test: make passt.mbuto script more robust")
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Creation of a symbolic link from /sbin to /usr/sbin fails if /sbin
exists and is non-empty. This is the case on Ubuntu-23.04.

We fix this by removing /sbin before creating the link.

Signed-off-by: Jon Maloy <jmaloy@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

In practical terms, passt doesn't benefit from the additional
protection offered by the AGPL over the GPL, because it's not
suitable to be executed over a computer network.

Further, restricting the distribution under the version 3 of the GPL
wouldn't provide any practical advantage either, as long as the passt
codebase is concerned, and might cause unnecessary compatibility
dilemmas.

Change licensing terms to the GNU General Public License Version 2,
or any later version, with written permission from all current and
past contributors, namely: myself, David Gibson, Laine Stump, Andrea
Bolognani, Paul Holzinger, Richard W.M. Jones, Chris Kuhn, Florian
Weimer, Giuseppe Scrivano, Stefan Hajnoczi, and Vasiliy Ulyanov.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Many of our tests are based around performing transfers of sample data
across passt/pasta created links.  The data flow here can be a bit
hard to follow since, e.g. we create a file transfer it to the guest,
then transfer it back to the host across several different tests.
This also means that the test cases aren't independent of each other.

Because we don't have the original file available at both ends in some
cases, we compare them by generating md5sums at each end and comparing
them, which is a bit complicated.

Make a number of changes to simplify this:
  1. Pre-generate the sample data files as a test asset, rather than
     building them on the fly during the tests proper
  2. Include the sample data files in the mbuto guest image
  3. Because we have good copies of the original data available in all
     contexts, we can now simply use 'cmp' to check if the transfer
     has worked, avoiding md5sum complications.
  4. Similarly we can always use the original copy of the sample data
     on the send side of each transfer, meaning that the tests become
     more independent of each other.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

We won't necessarily run mbuto as part of regular tests: it can also
be used for demos or out-of-tree tests.

To keep the profile simple, leave the whole sshd setup there, which
is otherwise harmless, but don't fail if guest-key.pub is missing in
the current directory.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

Extends the context system in the test scripts to allow executing commands
within a guest.  Do this without requiring an existing network in the guest
by using socat to run ssh via a vsock connection.

We do need some additional "sleep"s in the tests, because the new
faster dispatch means that sometimes we attempt to connect before
socat has managed to listen.

For now, only use this for the plain "passt" tests.  The "passt_in_ns" and
other tests have additional complications we still need to deal with.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>