passt, branch 2024_08_14.61c0b0d

flow: Don't crash if guest attempts to connect to port 0

2024-08-14T10:20:31+00:00

Using a zero port on TCP or UDP is dubious, and we can't really deal with
forwarding such a flow within the constraints of the socket API.  Hence
we ASSERT()ed that we had non-zero ports in flow_hash().

The intention was to make sure that the protocol code sanitizes such ports
before completing a flow entry.  Unfortunately, flow_hash() is also called
on new packets to see if they have an existing flow, so the unsanitized
guest packet can crash passt with the assert.

Correct this by moving the assert from flow_hash() to flow_sidx_hash()
which is only used on entries already in the table, not on unsanitized
data.

Reported-by: Matt Hamilton 
Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

conf: Don't ignore -t and -u options after -D

2024-08-14T07:14:12+00:00

f6d5a5239264 moved handling of -D into a later loop.  However as a side
effect it moved this from a switch block to an if block.  I left a couple
of 'break' statements that don't make sense in the new context.  They
should be 'continue' so that we go onto the next option, rather than
leaving the loop entirely.

Fixes: f6d5a5239264 ("conf: Delay handling -D option until after addresses are configured")
Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

ndp.c: Turn NDP responder into more declarative implementation

2024-08-13T17:46:16+00:00

- Add structs for NA, RA, NS, MTU, prefix info, option header,
  link-layer address, RDNSS, DNSSL and link-layer for RA message.

- Turn NA message from purely imperative, going byte by byte,
  to declarative by filling it's struct.

- Turn part of RA message into declarative.

- Move packet_add() to be before the call of ndp() in tap6_handler()
  if the protocol of the packet  is ICMPv6.

- Add a pool of packets as an additional parameter to ndp().

- Check the size of NS packet with packet_get() before sending an NA
  packet.

- Add documentation for the structs.

- Add an enum for NDP option types.

Link: https://bugs.passt.top/show_bug.cgi?id=21
Signed-off-by: AbdAlRahman Gad 
[sbrivio: Minor coding style fixes]
Signed-off-by: Stefano Brivio

conf: Delay handling -D option until after addresses are configured

2024-08-12T19:29:36+00:00

add_dns[46]() rely on the gateway address and c->no_map_gw being already
initialised, in order to properly handle DNS servers which need NAT to be
accessed from the guest.

Usually these are called from get_dns() which is well after the addresses
are configured, so that's fine.  However, they can also be called earlier
if an explicit -D command line option is given.  In this case no_map_gw
and/or c->ip[46].gw may not get be initialised properly, leading to this
doing the wrong thing.

Luckily we already have a second pass of option parsing for things which
need addresses to already be configured.  Move handling of -D to there.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

Correct inaccurate comments on ip[46]_ctx::addr

2024-08-12T19:29:21+00:00

These fields are described as being an address for an external, routable
interface.  That's not necessarily the case when using -a.  But, more
importantly, saying where the value comes from is not as useful as what
it's used for.  The real purpose of this field is as the address which we
assign to the guest via DHCP or --config-net.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

log: Don't prefix message with timestamp on --debug if it's a continuation

2024-08-12T14:21:53+00:00

If we prefix the second part of messages printed through
logmsg_perror() by the timestamp, on debug, we'll have two timestamps
and a weird separator in the result, such as this beauty:

  0.0013: Failed to clone process with detached namespaces0.0013: : Operation not permitted

Add a parameter to logmsg() and vlogmsg() which indicates a message
continuation. If that's set, don't print the timestamp in vlogmsg().

Link: https://github.com/moby/moby/issues/48257#issuecomment-2282875092
Signed-off-by: Stefano Brivio 
Reviewed-by: David Gibson

conf: Stop parsing options at first non-option argument

2024-08-08T19:34:06+00:00

Given that pasta supports specifying a command to be executed on the
command line, even without the usual -- separator as long as there's
no ambiguity, we shouldn't eat up options that are not meant for us.

Paul reports, for instance, that with:

  pasta --config-net ip -6 route

-6 is taken by pasta to mean --ipv6-only, and we execute 'ip route'.
That's because getopt_long(), by default, shuffles the argument list
to shift non-option arguments at the end.

Avoid that by adding '+' at the beginning of 'optstring'.

Reported-by: Paul Holzinger 
Signed-off-by: Stefano Brivio 
Reviewed-by: David Gibson

passt, util: Close any open file that the parent might have leaked

2024-08-08T19:31:25+00:00

If a parent accidentally or due to implementation reasons leaks any
open file, we don't want to have access to them, except for the file
passed via --fd, if any.

This is the case for Podman when Podman's parent leaks files into
Podman: it's not practical for Podman to close unrelated files before
starting pasta, as reported by Paul.

Use close_range(2) to close all open files except for standard streams
and the one from --fd.

Given that parts of conf() depend on other files to be already opened,
such as the epoll file descriptor, we can't easily defer this to a
more convenient point, where --fd was already parsed. Introduce a
minimal, duplicate version of --fd parsing to keep this simple.

As we need to check that the passed --fd option doesn't exceed
INT_MAX, because we'll parse it with strtol() but file descriptor
indices are signed ints (regardless of the arguments close_range()
take), extend the existing check in the actual --fd parsing in conf(),
also rejecting file descriptors numbers that match standard streams,
while at it.

Suggested-by: Paul Holzinger 
Signed-off-by: Stefano Brivio 
Reviewed-by: David Gibson 
Reviewed-by: Paul Holzinger

nstool: Propagate SIGTERM to processes executed in the namespace

2024-08-07T07:16:48+00:00

Particularly in shell it's sometimes natural to save the pid from a process
run and later kill it.  If doing this with nstool exec, however, it will
kill nstool itself, not the program it is running, which isn't usually what
you want or expect.

Address this by having nstool propagate SIGTERM to its child process.  It
may make sense to propagate some other signals, but some introduce extra
complications, so we'll worry about them when and if it seems useful.

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio

nstool: Fix some trivial typos

2024-08-07T07:16:45+00:00

Signed-off-by: David Gibson 
Signed-off-by: Stefano Brivio