Now that we can recognize the root dir in chaseat() sanely, let's use it
top optimize the very common special case where we have no root dir to
consider, and directly call open_tree().
Add a test case to verify that cat_files() correctly handles symlinks
to /dev/null (masked configuration files) and returns success (0)
instead of failing.
This test complements the fix for issue #40313.
Co-authored-by: Yu Watanabe <watanabe.yu+github@gmail.com>
Currently, pick_filter_image_any matches any image
with any suffix, which is way more than it should
be doing. It should only be matching images with
the .raw suffix.
Let's address this shortcoming by allowing to pass
multiple filters to path_pick(), and define
pick_filter_image_any as the combination of the
raw and directory image filters.
Fixes#40083
The current tree doesn't even compile with libidn(1) after
2c7bdaf9f1, which included
a non-existent call to check_dlopen_blocked() somehow.
Hence, it feels safe to just nuke legacy support from
our repo.
The `sg_adm` and `sg_mem` fields are not always set in shadow groups,
which can lead to issues with foreign tools like shadow's `sg` command.
Since other NSS implementations properly set these fields and it would
otherwise be impossible to access `administrators` and `members`
information from JSON files, it's bets to always fill these fields.
Even though `sg` is a nice example which should be already installed,
the issue itself can be reproduced with this simple program as well. It
relies on filled `sg_adm` and `sg_mem` fields just like `sg` does:
```
#include <err.h>
#include <gshadow.h>
#include <stdio.h>
int
main(int argc, char *argv[])
{
struct sgrp *s;
char **p;
if (argc != 2)
errx(1, "usage: poc group");
s = getsgnam(argv[1]);
printf("name: %s\n", s->sg_namp);
printf("admins:\n");
p = s->sg_adm;
while (*p != NULL) {
printf("- %s\n", *p);
p++;
}
printf("members:\n");
p = s->sg_mem;
while (*p != NULL) {
printf("- %s\n", *p);
p++;
}
}
```
Run it like this: `./poc root`
Proof of Concept (Arch Linux, which uses systemd with systemd-userdbd
and shadow's sg):
```
$ grep systemd /etc/nsswitch.conf
passwd: files systemd
group: files [SUCCESS=merge] systemd
shadow: files systemd
gshadow: files systemd
```
Issue with intrinsic groups:
Run as unprivileged user, who has no access to `/etc/gshadow` to trigger
nss-systemd (strace disables setuid of sg)
```
$ strace sg root
write(2, "sg: list.c:169: is_on_list: Asse"..., 61sg: list.c:169: is_on_list: Assertion `NULL != list' failed.
) = 61
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fa7e9c0c000
gettid() = 1882
getpid() = 1882
tgkill(1882, 1882, SIGABRT) = 0
--- SIGABRT {si_signo=SIGABRT, si_code=SI_TKILL, si_pid=1882, si_uid=1000} ---
+++ killed by SIGABRT (core dumped) +++
Aborted (core dumped) strace sg root
```
Issue with groups through systemd-userdbd:
1. Create a custom group (as root)
```
cat > /etc/userdb/sg-poc.group << EOF
{
"groupName": "sg-poc",
"gid": 6123,
"administrators": [
"root"
],
"members": [
"bin"
]
}
EOF
ln -s sg-poc.group /etc/userdb/6123.group
```
2. Verify that group actually exists
```
$ userdbctl group sg-poc
Group name: sg-poc
Disposition: regular
GID: 6123
Admins: root
Service: io.systemd.NameServiceSwitch
```
3. Run `sg` to switch into group `sg-poc` as regular user, this time
with setuid, i.e. no strace as before
```
$ sg sg-poc
sg: list.c:169: is_on_list: Assertion `NULL != list' failed.
Aborted (core dumped) sg sg-poc
```
Add a test for getsgnam_r to verify that sg_adm and sg_mem always point
to a NULL-terminated string vector.
Extend the gr_mem check of struct group for non-NULL values as well.
Note, this drops logging only test case for crypt_preferred_method(),
as that requires explicitly dlopen() the library. But, we should test
that make_salt() and friends automatically dlopen() it.
libcrypt was no longer built by default since glibc-2.38, and it has been
completely removed since glibc-2.39.
Let's always use libxcrypt, unless when building with musl. As already
major distribution already have libxcrypt-4.4.x, hence let's also bump
the required minimum version to 4.4.0.
libxcrypt cannot be built with musl, hence the previous fallback logic
in libcrypt-util.c are moved to musl/crypt.c.
Note, libxcrypt-4.4.0 was released on 2018-11-20.
See also #38608.
Major distributions already have libseccomp 2.5.x or newer.
Let's bump to the required minimum version to 2.4.0, which provides
SCMP_ACT_KILL_PROCESS, SCMP_ACT_LOG, SCMP_ARCH_PARISC, and
SCMP_ARCH_PARISC64.
Note, libseccomp 2.4.0 was released on 2019-03-15.
See also #38608.
All major distributions have switched to OpenSSL version 3.x.
Let's drop support of OpenSSL version 1.x.
Note, OpenSSL 3.0 was released on 2021-09-07 (and will be EOL on 2026-09-07).
See also #38608.
Let's move this from user-record.c into generic code and let's beef it
up a bit: allow parsing octal strings. This is particular relevant given
json_variant_new_stat() generates the mode in that format, and we
probably should be able to parse our own fields (even though we
currently don't do that for the data from json_variant_new_stat()).
Allow CPUSchedulingPolicy to be set to "ext". SCHED_EXT is a new
scheduling policy in Linux v6.12 that allows processes to be scheduled
using custom BPF schedulers instead of the default in-kernel ones.
Selectively setting the SCHED_EXT policy is useful for systems running
in "partial mode" where not all processes are run using a custom
scheduler.
Fallback to SCHED_OTHER and print an error message for systems where
SCHED_EXT isn't available.
Now that sd-event doesn't insist on blocking
SIGCHLD anymore when watching for process exit,
let's stop blocking SIGCHLD tree-wide where not
required anymore.
Loading images is, generally speaking, the slowest part of sd-executor
when spawning a service. This is due to multiple factors. dm-verity is
obviously a big part of the cost, but dissecting in general via libblkid
also can take a lot of time, due to probing the images and their
filesystems.
A performance test doing service restarts in a row shows these
results, ran on a production system (low power and slow ARM64 SOC) with
a real production service, show the following service interruption
intervals:
```
Count | P50 (ms) | P90 (ms) | P95 (ms) | P99 (ms) | P99.9 (ms)
507 | 1,532 | 1,726 | 2,548 | 4,112 | 4,592
```
One iteration is 507 restarts in this case, but this has ran hundreds
of times and the results are always in line within margin of error.
This also holds true for metrics from live systems, same numbers.
Between 1.0s and 1.2s can be attributed by profiling to the time needed
for the service code itself to start up and sd_notify, the rest is spent
inside systemd's code.
This means there is currently a tradeoff for services - either use
secure
images, or make restarting fast. Downtime of services is a very
important
metric, as for many cases this directly translates to outages, total or
partial (blackouot or greyout).
In order to facilitate using secure images without downsides, skip the
slow dissect steps (probing, loop devices, etc) when the configured
image is a single filesystem dm-verity image with a policy that pins it
to a single filesystem, and an already existing and open dm-verity
device
can be found and reused.
This allows orchestrators to pre-open images on download, before
restarting
services, to minimize downtimes.
Authenticated disk encryption is experimentally supported by cryptsetup
since v2.0.0 and allows for automatic dm-integrity setup for LUKS
devices. Add support for the mode to systemd-repart. The PR adds support
for `cryptsetup luksFormat --integrity` to systemd-repart and
"encryptedwithintegrity" dissection policy.
Limitations:
- No discard, online-only mode for repart.
Closes#39250
LUKS2 supports built-in integrity checking which may come very handy to
mitigate partial rollback attacks on the storage when only some specific
parts are restored to some old encrypted state. Specific use-cases like
Confidential VMs may want to mandate the usage of feature e.g. on the root
volume. Introduce "encryptedwithintegrity" image policy to support that.
Note, due to the current libcryptsetup limitations, checking whether the
feature is enabled or not for the 'file' case (e.g. DDI image as a raw file)
requires setting up a loop device. To avoid that and keep dissect fully
functional when working unpriviliged, implement a minimal custom LUKS header
parser.
The kernel prevents you from open_tree()'ing an open_tree() fd unless it
was created from the caller's mount namespace. For various use cases, we
want to be able to open_tree() arbitrary mount file descriptors. Turns
out there's a way go get around it by mounting the mount file descriptor
in a throw-away mount namespace and then open_tree()'ing the mount file
descriptor. Let's implement this as a new helper mount_fd_clone() and
add a test for it.
Because move_mount()'ing the original fd makes it pretty useless as it
can't be move_mount()'ed again, we optionally make a second clone which
can replace the original fd so it can be cloned again later.
Usually we gracefully ignore unknown configuration parameters, so that
service files can be written by upstreams and used across a variegated
range of distributions with various versions of systemd, to avoid
forcing users to the minimum common denominator and only adding settings
that are supported by the oldest distro supported.
Image policies do not behave like this, and any unknown partition or
policy designator causes the whole unit to fail to parse and a hard
error.
Change it so that parsing RootImagePolicy and friends via unit file or
D-Bus logs but otherwise ignores unknown specifiers, like other options
do.
This allows us to add new specifiers in the future, and users to adopt
them immediately.
Follow-up for d452335aa4
Alpine/postmarketOS build coreutils with --enable-single-binary=symlinks.
In that case, all commands provided by coreutils are symlink to
/usr/bin/coreutils, and it calls prctl(PR_SET_NAME, argv[0]), hence the comm
will be the path to the symlink.
This also makes not kill sleep command with SIGKILL in TEST-17-UDEV, that is
totally unnecessary.
Mike Yuan
Lennart Poettering
gvenugo3andYu Watanabe
Daan De Meyer
Usama Arif
Tobias Stoeckmann
Luiz Amaral
Matt Fleming
Luca Boccassi
Luca Boccassi
Vitaly Kuznetsov