To reach (at least) a conceptually equivalent security level as
implemented by --enable-sandbox in slirp4netns, we need to create a
new mount namespace and pivot_root() into a new (empty) mountpoint, so
that passt and pasta can't access any filesystem resource after
initialisation.
While at it, also detach IPC, PID (only for passt, to prevent
vulnerabilities based on the knowledge of a target PID), and UTS
namespaces.
With this approach, if we apply the seccomp filters right after the
configuration step, the number of allowed syscalls grows further. To
prevent this, defer the application of seccomp policies after the
initialisation phase, before the main loop, that's where we expect bad
things to happen, potentially. This way, we get back to 22 allowed
syscalls for passt and 34 for pasta, on x86_64.
While at it, move #syscalls notes to specific code paths wherever it
conceptually makes sense.
We have to open all the file handles we'll ever need before
sandboxing:
- the packet capture file can only be opened once, drop instance
numbers from the default path and use the (pre-sandbox) PID instead
- /proc/net/tcp{,v6} and /proc/net/udp{,v6}, for automatic detection
of bound ports in pasta mode, are now opened only once, before
sandboxing, and their handles are stored in the execution context
- the UNIX domain socket for passt is also bound only once, before
sandboxing: to reject clients after the first one, instead of
closing the listening socket, keep it open, accept and immediately
discard new connection if we already have a valid one
Clarify the (unchanged) behaviour for --netns-only in the man page.
To actually make passt and pasta processes run in a separate PID
namespace, we need to unshare(CLONE_NEWPID) before forking to
background (if configured to do so). Introduce a small daemon()
implementation, __daemon(), that additionally saves the PID file
before forking. While running in foreground, the process itself can't
move to a new PID namespace (a process can't change the notion of its
own PID): mention that in the man page.
For some reason, fork() in a detached PID namespace causes SIGTERM
and SIGQUIT to be ignored, even if the handler is still reported as
SIG_DFL: add a signal handler that just exits.
We can now drop most of the pasta_child_handler() implementation,
that took care of terminating all processes running in the same
namespace, if pasta started a shell: the shell itself is now the
init process in that namespace, and all children will terminate
once the init process exits.
Issuing 'echo $$' in a detached PID namespace won't return the
actual namespace PID as seen from the init namespace: adapt
demo and test setup scripts to reflect that.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
With a recent 5.15 kernel, passing a huge window size to iperf3 with
lower MTUs makes iperf3 stop sending packets after a few seconds --
I haven't investigated this in detail, but the window size will be
adjusted dynamically anyway and not passing it doesn't actually
affect throughput, so simply drop the option.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Some recent change to xenial-updates broke dependencies for gcc,
it can't be installed anymore. Skipping apt-get update leaves gcc
dependencies in a consistent state, though.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The shell might report 'nc -6 -l -p 9999 > /tmp/ns_msg' as done
even after the subsequent 'echo' is done: wait one second before
reading out /tmp/ns_msg, to ensure we read that instead of the
"Done" message.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The new tests check build and a simple case with pasta sending a
short message in both directions (namespace to init, init to
namespace).
Tests cover a mix of Debian, Fedora, OpenSUSE and Ubuntu combinations
on aarch64, i386, ppc64, ppc64le, s390x, x86_64.
Builds tested starting from approximately glibc 2.19, gcc 4.7, and
actual functionality approximately from 4.4 kernels, glibc 2.25,
gcc 4.8, all the way up to current glibc/gcc/kernel versions.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
For distribution tests, we'll repeat some tests frequently. Add a
'def' directive that starts a block, ended by 'endef', whose
execution can then be triggered by simply giving its name as a
directive itself.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
We might have highlighting and slightly different prompts across
different distributions, allow a more reasonable set of prompt
strings to be accepted as prompts.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
The throughput results in this test look quite variable, slightly
lower figures look reasonable anyway.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Debug information might be printed after a prompt is seen,
just wait those 3 seconds and be done with it.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
An inline comment prefixed by a space doesn't mean the space
is dropped, and sleep(1) will get a blank in its argument.
Move the comment on its own line.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
They'll start DAD as we bring up the interface, and the DHCPv6
client might be unreasonably delayed if we start it too early.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
...mostly false positives, but a number of very relevant ones too,
in tcp_get_sndbuf(), tcp_conn_from_tap(), and siphash PREAMBLE().
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
With recent improvements, we're not CPU-bound at all while testing
UDP performance. Give the VM more memory and CPUs, forward two
additional ports, start up to four threads in parallel, and give
single iperf3 threads higher bandwidth targets.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
On most recent CPUs, that's a better indication of all-core turbo
frequency, or non-turbo frequency, than /proc/cpuinfo.
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
SPDX tags don't replace license files. Some notices were missing and
some tags were not according to the SPDX specification, too.
Now reuse --lint from the REUSE tool (https://reuse.software/) passes.
Reported-by: Martin Hauke <mardnh@gmx.de>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Based on a patch from Giuseppe Scrivano, this adds the ability to:
- specify paths and names of target namespaces to join, instead of
a PID, also for user namespaces, with --userns
- request to join or create a network namespace only, without
entering or creating a user namespace, with --netns-only
- specify the base directory for netns mountpoints, with --nsrun-dir
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
[sbrivio: reworked logic to actually join the given namespaces when
they're not created, implemented --netns-only and --nsrun-dir,
updated pasta demo script and man page]
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
