Commit graph

916 commits

Author SHA1 Message Date
Stefano Brivio
df29ebfe02 test/perf: Disable periodic throughput reports to avoid vhost hang
It appears that if we run throughput tests with one-second periodic
reports, the sending side of the vhost channel used for SSH-based
command dispatch occasionally stops working altogether. I haven't
investigated this further, all I see is that output is truncated
at some point, and doesn't resume.

If we use gzip compression (ssh -C) this happens less frequently,
but it still happens, seemingly indicating the issue is probably
related to vhost itself.

Disable periodic reports in iperf3 clients. The -i options were
actually redundant, so remove them from both test files as well as
from test_iperf3().

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-22 16:54:09 +02:00
Stefano Brivio
9f8b783d4a test/lib: Wait on iperf3 clients to be done, then send SIGINT to servers
An iperf3 client might fail to send the control message indicating
the end of the test, if the kernel buffer doesn't accept it, and exit
without having sent it, as the control socket is non-blocking. Should
this happen, the server will just wait forever for this message,
instead of terminating.

Restore some of the behaviour that went away with the
"test: Rewrite test_iperf3" patch: instead of waiting on servers to
terminate, wait on the clients. When they are done, wait 2 seconds,
and then send SIGINT to the servers, which make them still write
out the JSON report before terminating.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-22 16:54:09 +02:00
Stefano Brivio
119bb265a3 test/lib: Restore IFS while executing directives in def blocks
If we don't, guest command dispatch will fail altogether, given that
we use cat(1) on the enter file, which contains spaces.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-22 16:54:09 +02:00
Stefano Brivio
4a1b675278 conf, tcp, udp: Arrays for ports need 2^16 values, not 2^16-8
Reported by David but also by Coverity (CWE-119):

	In conf_ports: Out-of-bounds access to a buffer

...not in practice, because the allocation size is rounded up
anyway, but not nice either.

Reported-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-22 16:54:09 +02:00
Stefano Brivio
d30bde3181 tap: Check return value of accept4() before calling getsockopt()
Reported by Coverity (CWE-119):

	Negative value used as argument to a function expecting a
	positive value (for example, size of buffer or allocation)

and harmless, because getsockopt() would return -EBADF if the
socket is -1, so we wouldn't print anything.

Check if accept4() returns a valid socket before calling getsockopt()
on it.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-22 16:54:01 +02:00
Stefano Brivio
a39398e840 test/perf: Switch performance test duration to 10 seconds instead of 30
It looks like the workaround for the virtio_net TX hang issue is
working less reliably with the new command dispatch mechanism, I'm
not sure why. Switch to 10 seconds, at least for the moment.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-22 16:53:55 +02:00
Stefano Brivio
df3a35c203 test/perf: Always use /sbin/sysctl in tcp test
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-22 16:53:35 +02:00
Stefano Brivio
47d424d083 README: Update Availability and Try It sections with new packages
We now have official packages for Fedora, unofficial (Fedora Copr)
for other common RPM-based distributions, and the existing
packages with static builds for Debian, and for other RPM-based
distributions.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-22 16:53:35 +02:00
Stefano Brivio
fafdda083f test/passt_in_ns: Consistent sleep commands before starting socat client
There are some 'sleep 1' commands between starting the socat server
and its corresponding client to avoid races due to the server not
being ready as we start sending data.

However, those don't cover all the cases where we might need them,
and in some cases the sleep command actually ended up being before
the server even starts.

This fixes occasional failures in TCP and UDP simple transfer tests,
that became apparent with the new command dispatch mechanism.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-22 16:53:35 +02:00
Stefano Brivio
ae51d2dac1 test/perf: Check for /sbin/sysctl with which(1), not simply sysctl
Otherwise, we're depending on having /sbin in $PATH. For some reason
I didn't completely grasp, with the new command dispatch mechanism
that's not the case anymore, even if I have /sbin in $PATH in the
parent shell.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-22 16:53:35 +02:00
Stefano Brivio
8627a2da52 doc/demo: Clone and use mbuto in init namespace
...and not in pasta's namespace: the fakeroot(1) version shipping
with (at least) Fedora 36 assumes "nested" operation as it sees that
the UID is 0, and claims it's not supported.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-22 16:53:35 +02:00
Stefano Brivio
efd9d9b456 doc/demo: Drop /sbin from dhclient command, pass script file explicitly
dhclient might be in /usr/sbin on recent versions of Fedora, and
mbuto just adds it to the same location as it was on the host:
just call dhclient instead of /sbin/dhclient.

This also applies for dhclient-script: given that we create the file
on boot, pass its explicit location with -sf.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
2022-09-22 16:53:35 +02:00
Stefano Brivio
6655625c30 Makefile: Include seccomp.h in HEADERS and require it for static checkers
Targets running static checkers (cppcheck and clang-tidy) need
seccomp.h, but the latter is not included in HEADERS. Add it.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-22 16:53:35 +02:00
Stefano Brivio
512f5b1aab Makefile: Allow define overrides by prepending, not appending, CFLAGS
If we append CFLAGS to the ones passed via command line (if any),
-D options we append will override -D options passed on command line
(if any).

For example, OpenSUSE build flags include -D_FORTIFY_SOURCE=3, and we
want to have -D_FORTIFY_SOURCE=2, if and only if not overridden. The
current behaviour implies we redefine _FORTIFY_SOURCE as 2, though.

Instead of appending CFLAGS, prepend them by adding all the default
build flags to another variable, a simply expanded one (defined with
:=), named FLAGS, and pass that *before* CFLAGS in targets, so that
defines from command line can override default flags.

Reported-by: Dario Faggioli <dfaggioli@suse.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Tested-by: Dario Faggioli <dfaggioli@suse.com>
2022-09-22 16:53:09 +02:00
Stefano Brivio
b323e5f439 test: term: When checking if status line is a number, hide errors
We use the [ "$x" -eq "$x" ] syntax to check if $x is a number. The
behaviour is clearly implied by POSIX, but some shells might actually
report the (intended) error, and dash floods script.log with
"Illegal number" error messages. Hide them.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-14 20:49:08 +02:00
David Gibson
9fc476af6e test: Simpler termination handling for UDP tests
Because UDP is connectionless we don't have an in-built end-of-stream
signal for our connectivity tests.  We work around this by explicitly
adding an end marker to our sample data and killing the listening end once
it is seen.

However, socat has some built-in options - null-eof and shut-null - which
can be used to signal the end of stream with a zero-length UDP packet.
Use these to simplify how the UDP tests are implemented.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:14:29 +02:00
David Gibson
af9c98af5f udp: Don't drop zero-length outbound UDP packets
udp_tap_handler() currently skips outbound packets if they have a payload
length of zero.  This is not correct, since in a datagram protocol zero
length packets still have meaning.

Adjust this to correctly forward the zero-length packets by using a msghdr
with msg_iovlen == 0.

Bugzilla: https://bugs.passt.top/show_bug.cgi?id=19

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:14:29 +02:00
David Gibson
484652c632 udp: Don't pre-initialize msghdr array
In udp_tap_handler() the array of msghdr structures, mm[], is initialized
to zero.  Since UIO_MAXIOV is 1024, this can be quite a large zero, which
is expensive if we only end up using a few of its entries.  It also makes
it less obvious how we're setting all the control fields at the point we
actually invoke sendmmsg().

Rather than pre-initializing it, just initialize each element as we use it.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:14:29 +02:00
David Gibson
6f2db0e34b test: Move perf.js report file to $LOGDIR/web
The tests generate a performance report in $BASEPATH/perf.js and
hooks/pre-push copies it to the website.  To avoid cluttering the working
directory, instead put perf.js in $LOGDIR/web, since it's a test output
artefact.  Update hooks/pre-push to copy from its new location.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
4e9b50f7b6 test: Move video processing files to $STATEBASE
The asciinema video handling creates a number of temporary files (.uncat,
.start, .stop) which currently go into the source tree.  Put them in the
temporary state directory to avoid clutter.

The final processed output is now placed into test_logs/web/ along with the
corresponding .js file with links, since they're essentially test
artefacts.  hooks/pre-push is updated to look for those files in the new
location when updating the web site.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
ec6af08ca7 demo: Move pidfiles to state directory
Avoiding putting them in bare /tmp means they will be automatically
cleaned up with everything else.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
d813660107 test: Move pidfiles and nsholder sockets into state directory
Currently they go in the passt source tree with a fixed names, which means
their presence can mess with subsequent test runs.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
b23adf7132 test: Store pcap files in $LOGDIR instead of /tmp
The capture files are more or less a different form of log output from the
tests, so place them in $LOGDIR.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
07aa24499e test: Move pause temporary file to state directory
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
1c36c8d3f8 test: Use paths in __STATEDIR__ instead of 'temp' and 'tempdir' directives
Instead of using the 'temp' and 'tempdir' DSL directives to create
temporary files, use fixed paths relative to __STATEDIR__.  This has two
advantages:
  1) The files are automatically cleaned up if the tests fail (and even if
     that doesn't work they're easier to clean up manuall)
  2) When debugging tests it's easier to figure out which of the temporary
     files are relevant to whatever's going wrong

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
c71a5e8528 test: Don't redundantly regenerate small test file in pasta/tcp
In what looks like a copy/paste error, pasta/tcp generates its small test
file twice.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
54c5addeaa test: Move context temporary files to state dir
Currently the context command dispatch subsystem creates a bunch of
temporary files in $LOGDIR, which is messy.  Store them in $STATEDIR which
is for precisely this purpose.  The logs from each context still go into
$LOGDIR.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
e4ecb6d795 test: Move passt_test_log_pipe to state directory
We use this fifo to send messages to the information pane.  Put it in the
state directory so it doesn't need its own cleanup.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
8cb7d5b461 test: Create common state directories for temporary files
The test scripts create a bunch of temporary files to keep track of
internal state.  Some are made in /tmp with individual mktemp calls, some
go in the passt source directory, and some go in $LOGDIR.  This can
sometimes make it messy to clean up after failed test runs.

Start cleaning this up by creating a single "state" directory ($STATEBASE)
in /tmp for all the state or temporary files used by a single test run.
Clean it up automatically in cleanup() - except when DEBUG==1, because
those files can be useful for debugging test script failures.

We create subdirectories under $STATEBASE for each setup function, exposed
as $STATESETUP.  We also create subdirectories for each test script and
expose those to the scripts as __STATEDIR__.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
1e4a15398f test: Actually run cleanup function
We install a cleanup() function with 'trap' in order to clean up temporary
files we generate during the tests.  However, we deinstall it after
run_term, which means it won't run in most of the cases where it would be
useful.  Even if "run from_term" exits with an error, that error will be
hidden from the run_term wrapper because it's within a tmux session, so we
will return from run_term normally, uninstall the trap and never clean up.

In fact there's no reason to uninstall the trap at all, it works just as
well on the success exit path as an error exit path.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
a9b18300b4 test: Remove unused variable FFMPEG_PID_FILE
FFPMPEG_PID_FILE is set (creating a temporary file), then never used.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
594c2f9371 test: Group tests by mode then protocol, rather than the reverse
For example, passt/dhcp rather than dhcp/passt.  This is more
consistent with the two_guests and other test groups, and makes some
other cleanups simpler.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 11:12:41 +02:00
David Gibson
4381278b7d test: Use new-style command issue for passt_in_ns tests
Put the pieces together to use the new style context based dispatch for
the passt_in_pasta tests.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
87a57156cf test: Use context system for two_guests tests
Now that we have all the pieces we need for issuing commands both into
namespaces and into guests, we can use those to convert the two_guests to
using only the new style context command issue.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
56e755ba11 test: Use context system for guest commands
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>
2022-09-13 05:32:00 +02:00
David Gibson
a8a437abd6 test: Extend context system to run commands in namespace for pasta tests
Extend the context system to allow commands to be run in a namespace
created with unshare, and use it for the namespace used in the pasta tests.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
a8c32c85d5 test: Add nsholder utility
In our test scripts we need to do some ugly parsing of /proc and/or pstree
output in order to get the PIDs of processes running in namespaces so that
we can connect to those namespaces with nsenter or pasta.

This is actually a pretty tricky problem with standard tools.  To determine
the PID from the outside of the namespace we need to know how the process
of interest is related to the unshare or pasta process (child? one of
several children? grandchild?) as well as then parsing /proc or ps output.
This is slightly awkward now, and will get worse with future changes I'd
like to make to have processes are dispatched.

The obvious solution would be to have the process of interest (which we
control) report its own PID, but that doesn't work easily, because it is in
a PID namepace and sees only its local PID not the global PID we need to
address it from outside.

To handle this, add a small custom tool, "nsholder".  This takes a path
and a mode parameter.  In "hold" mode it will create a unix domain socket
bound to the path and listening.  In "pid" mode it will get the "hold"ing
process's pid via the unix socket using SO_PEERCRED, which translates
between PID namespaces.  In "stop" mode it will send a message to the
socket causing the "hold"ing process to clean up and exit.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
2f87265d8b test: Use new-style contexts for passt pane in the pasta and passt tests
Convert the pasta and passt tests to use new-style context execution
for the things that run in the "passt" frame.  Don't touch the
passt_in_ns or two_guests tests yet, because they run passt inside a
namespace which introduces some additional complications we have yet
to handle.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
d9b9c252cd test: Issue host commands via context for most tests
Convert most of the tests to use the new-style system for issuing commands
for all host commands.  We leave the distro tests for now: they use
the same pane for both host and guest commands which we'll need some more
things to deal with.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
c2f248588b test: Integration of old-style pane execution and new context execution
We're creating a system for tests to more reliably execute commands in
various contexts (e.g. host, guest, namespace).  That transition is going
to happen over a number of steps though, so in the meantime we need to deal
with both the old-style issuing of commands via typing into and screen
scraping tmux panels, and the new-style system for executing commands in
context.

Introduce some transitional helpers which will issue a command via context
if the requested context is initialized, but will otherwise fall back to
the old style tmux panel based method.  Re-implement the various test DSL
commands in terms of these new helpers.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
a32df9b6f4 test: Allow a tmux pane to watch commands executed in contexts
We're moving to a new way of the tests dispatching commands to running in
contexts (host, guest, namespace, etc.).  As we make this transition,
though, we still want the user to be able to watch the commands running
in a context, as they previously could from the commands issued in the
pane.

Add a helper to set up a pane to watch a context's log to allow this.  In
some cases we currently issue commands from several different logical
contexts in the same pane, so allow a pane to watch several contexts at
once.  Also use tail's --retry option to allow starting the watch before
we've initialized the context which will be useful in some cases.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
3c47b65a64 test: Context execution helpers
For the tests, we need to run commands in various contexts: in the host,
in a guest or in a namespace.  Currently we do this by running each context
in a tmux pane, and using tmux commands to type the commands into the
relevant pane, then screen-scrape the output for the results if we need
them.

This is very fragile, because we have to make various assumptions to parse
the output.  Those can break if a shell doesn't have the prompt we expect,
if the tmux pane is too small or in various other conditions.

This starts some library functions for a new "context" system, that
provides a common way to invoke commands in a given context, in a way that
properly preserves stdout, stderr and the process return code.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
4fbd0a8ff9 test: Correctly match "background" with "wait" commands
Our test DSL has a number of paired commands to run something in the
background in a pane, then later to wait for it to complete.  However, in
some of the tests we have these mismatched - starting a command in one
pane, then waiting for it in another.

We appear to get away with this for some reason, but it's not correct and
future changes make it cause more problems.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:32:00 +02:00
David Gibson
ef6da15732 Allow --userns when pasta spawns a command
Currently --userns is only allowed when pasta is attaching to an existing
netns or PID, and is prohibited when creating a new netns by spawning a
command or shell.

With the new handling of userns, this check isn't neccessary.  I'm not sure
if there's any use case for --userns with a spawned command, but it's
strictly more flexible and requires zero extra code, so we might as well.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:31:51 +02:00
David Gibson
eed17a47fe Handle userns isolation and dropping root at the same time
passt/pasta can interact with user namespaces in a number of ways:
   1) With --netns-only we'll remain in our original user namespace
   2) With --userns or a PID option to pasta we'll join either the given
      user namespace or that of the PID
   3) When pasta spawns a shell or command we'll start a new user namespace
      for the command and then join it
   4) With passt we'll create a new user namespace when we sandbox()
      ourself

However (3) and (4) turn out to have essentially the same effect.  In both
cases we create one new user namespace.  The spawned command starts there,
and passt/pasta itself will live there from sandbox() onwards.

Because of this, we can simplify user namespace handling by moving the
userns handling earlier, to the same point we drop root in the original
namespace.  Extend the drop_user() function to isolate_user() which does
both.

After switching UID and GID in the original userns, isolate_user() will
either join or create the userns we require.  When we spawn a command with
pasta_start_ns()/pasta_setup_ns() we no longer need to create a userns,
because we're already made one.  sandbox() likewise no longer needs to
create (or join) an userns because we're already in the one we need.

We no longer need c->pasta_userns_fd, since the fd is only used locally
in isolate_user().  Likewise we can replace c->netns_only with a local
in conf(), since it's not used outside there.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:31:51 +02:00
David Gibson
d9f889a55a Correctly handle --netns-only in pasta_start_ns()
--netns-only is supposed to make pasta use only a network namespace, not
a user namespace.  However, pasta_start_ns() has this backwards, and if
--netns-only is specified it creates a user namespace but *not* a network
namespace.  Correct this.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:31:51 +02:00
David Gibson
fc1be3d5ab Clean up and rename conf_ns_open()
conf_ns_open() opens file descriptors for the namespaces pasta needs, but
it doesnt really have anything to do with configuration any more.  For
better clarity, move it to pasta.c and rename it pasta_open_ns().  This
makes the symmetry between it and pasta_start_ns() more clear, since these
represent the two basic ways that pasta can operate, either attaching to
an existing namespace/process or spawning a new one.

Since its no longer validating options, the errors it could return
shouldn't cause a usage message.  Just exit directly with an error instead.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:31:51 +02:00
David Gibson
e8b19a4bd2 Consolidate validation of pasta namespace options
There are a number of different ways to specify namespaces for pasta to
use.  Some combinations are valid and some are not.  Currently validation
for these is spread across several places: conf_ns_pid() validates PID
options specifically.  Near its callsite in conf() several other checks
are made. Some additional checks are made in conf_ns_open() and finally
theres a check just before the call to pasta_start_ns().

This is quite hard to follow.  Make it easier by putting all the validation
logic together in a new conf_pasta_ns() function, which subsumes
conf_ns_pid().  This reveals that some of the checks were redundant with
each other, so remove those.

For good measure, rename conf_netns() to conf_netns_opt() to make it
clearer its handling just the --netns option specifically, not overall
configuration of the netns.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:31:51 +02:00
David Gibson
d72a1e7bb9 Move self-isolation code into a separate file
passt/pasta contains a number of routines designed to isolate passt from
the rest of the system for security.  These are spread through util.c and
passt.c.  Move them together into a new isolation.c file.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:31:51 +02:00
David Gibson
5d3b50c100 Safer handling if we can't open /proc/self/uid_map
passt is allowed to run as "root" (UID 0) in a user namespace, but notas
real root in the init namespace.  We read /proc/self/uid_map to determine
if we're in the init namespace or not.

If we're unable to open /proc/self/uid_map we assume we're ok and
continue running as UID 0.  This seems unwise.  The only instances I
can think of where uid_map won't be available are if the host kernel
doesn't support namespaces, or /proc is not mounted.  In neither case
is it safe to assume we're "not really" root and continue (although in
practice we'd likely fail for other reasons pretty soon anyway).

Therefore, fail with an error in this case, instead of carrying on.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2022-09-13 05:31:51 +02:00