These source files uses symbols provided by sched.h, e.g.
setns(), unshare(), CLONE_NEWNS, and friends, but they do not explicitly
include sched.h. Currently, it is included indirectly via missing_syscall.h,
which is included by e.g. pidfd-util.h.
Let's explicitly include headers that provides symbols used in the code.
This is similar to 4f18ff2e29, but for sched.h.
We use symbols provided by unistd.h without including it. E.g.
open(), close(), read(), write(), access(), symlink(), unlink(), rmdir(),
fsync(), syncfs(), lseek(), ftruncate(), fchown(), dup2(), pipe2(),
getuid(), getgid(), gettid(), getppid(), pipe2(), execv(), _exit(),
environ, STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO, F_OK, and their
friends and variants, so on.
Currently, unistd.h is indirectly included mainly in the following two paths:
- through missing_syscall.h, which is planned to covert to .c file.
- through signal.h -> bits/sigstksz.h, which is new since glibc-2.34.
Note, signal.h is included by sd-eevent.h. So, many source files
indirectly include unistd.h if newer glibc is used.
Currently, our baseline on glibc is 2.31. We need to support glibc older
than 2.34, but unfortunately, we do not have any CI environments with
such old glibc. CIFuzz uses glibc-2.31, but it builds only fuzzers, and
many files are even not compiled.
Now that the necessary functions from log.h have been moved to macro.h,
we can stop including log.h in macro.h. This requires modifying source
files all over the tree to include log.h instead.
This is a simple helper for creating a userns that just maps the
callers user to UID 0 in the namespace. This can be acquired unpriv,
which makes it useful for various purposes, for example for the logic in
is_idmapping_supported(), hence port it over.
(is_idmapping_supported() used a different mapping before, with the
nobody users, but there's no real reason for that, and we'll use
userns_acquire_self_root() elsewhere soon, where the root mapping is
important).
Unprivileged namespaces are only allowed if the "setgroups" file is set
to "deny" for processes. And we need to write it before writing the
gidmap. Hence add a parameter for that.
Then, also patch all current users to actually enable this. The usecase
generally don't need it (because they don't care about unprivileged
userns), but it doesn't hurt to enable the concept anyway in all current
users (none of them actually runs complex userspace in them, but they
mostly use userns_acquire() for idmapped mounts and similar).
Let's anyway make this option explicit in the function call, to indicate
that the concept exists and is applied.
To resolve conflict with sys/mount.h and linux/mount.h or linux/fs.h.
The conflict between sys/mount.h and linux/mount.h is resolved in
glibc-2.37 (774058d72942249f71d74e7f2b639f77184160a6), but our baseline
is still glibc-2.31. Also, even with the version or newer, still
sys/mount.h conflicts with linux/fs.h, which is included by
linux/btrfs.h.
This introduces our own implementation of sys/mount.h, that can be
simultaneously included with linux/mount.h and linux/fs.h. This also
imports linux/fs.h, linux/mount.h, and several other dependent headers.
The introduced sys/mount.h header itself may not be enough simple, but
by using the header, we can drop most of workarounds in other source files.
Often we want to fork off a process that just hangs until we kill it,
let's add a simple flag to create one of this type, and use it at
various places.
This makes sure the the codepath that derives an nsfd from a pid works
the same for the pidfd case and the non-pidfd case: if we can verify
that /proc/ is mounted but the /proc/$PID/ns/ files are missing, we can
assume the ns type is not supported by the kernel. Hence return the same
ENOPKG error in this case as we already do in the pidfd ioctl based
codepath.
- Make fd_is_namespace() take NamespaceType
- Drop support for kernel without NS_GET_NSTYPE (< 4.11)
- Port is_our_namespace() to namespace_open_by_type()
(preparation for later commits, where the latter
would go by pidfd if available, avoiding procfs)
[ 10.056930] (journald)[104]: Failed to fork off '(sd-mkuserns)': Invalid argument
[ 10.063727] systemd[1]: systemd-modules-load.service: About to execute: /usr/lib/systemd/systemd-modules-load
[ 10.071148] (journald)[104]: Failed to fork process (sd-mkuserns): Invalid argument
safe_fork_full() already logs at debug level, so the caller shouldn't.
As reported in https://github.com/systemd/systemd/issues/35400,
on riscv64, with Linux version 6.6.51-linux4microchip+fpga-2024.09, we get:
[ 10.063727] systemd[1]: systemd-modules-load.service: About to execute: /usr/lib/systemd/systemd-modules-load
[ 10.071148] (journald)[104]: Failed to fork process (sd-mkuserns): Invalid argument
Fixes https://github.com/systemd/systemd/issues/35400.
'r' is used to make the repeated checks shorter. Without that, the long variable
name is distracting.
This is a more comprehensive fix compared to #35273. Also adds a minimal
test only.
Based on Luca's #35273 but generalizes the code a bit.
In v258 we really should get rid of the old heuristics around userns and
cgroupns detection, but given we are late in the v257 cycle this keeps
them in.
We do this already in all string lookup tables. This way
it's guaranteed that iterators which ends with _NAMESPACE_TYPE_MAX
wouldn't overrun the array.
Yu Watanabe
Daan De Meyer
Mike Yuan
Michal Sekletar
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Andres Beltran
Sam Leonard