Julia Kartseva [Thu, 6 Jan 2022 00:34:56 +0000 (16:34 -0800)]
bpf: do not freeze if bpf lsm fails to set up
BPF LSM is cgroup unaware and it's set up is happening in core manager.
It occures that the current implementation is too restrictive and causes
pid 1 to freeze.
Instead:
* in bpf_lsm_setup set manager->restrict_fs pointer last,
so it is an indicator that the set up was successful
* check for manager->restrict_fs before applying unit options
If the action failed, we should log about the issue, and continue.
Exiting would bring the graphical session down, which of course is not
appreciated by users.
As documented in previous commits, a non-negative return from the callback
doesn't matter, so the callback is simplified a bit.
It was copy-pasted directly from OSS-Fuzz where it makes sense to
kind of strip binaries to get nice backtraces but when the fuzzers
are built and run locally with gdb it would be nice to have a little
bit more than that.
It was initially discovered in elfutils where I put the same flags
and was surprised when I couldn't run the fuzzer comfortably step
by step, which led to the same change there: https://github.com/google/oss-fuzz/pull/7092
:-)
network: move logging from tc .fill_message to the callers
Structured initialization is used a bit more.
There were two kinds of log messages: about failed size calculations and
about failed appends to the message. I "downgraded" the first type to log_debug,
and moved the latter to the caller. This way there should be at most one high-priority
message.
I also changed sizeof(<type>) to sizeof(var) — there is less chance of select-and-paste
error in the second form.
network: simplify logging in l2tp_create_session() and l2tp_create_tunnel()
All the detailed logging is replaced by a simple "Failed to create netlink message",
which should be enough for the user in the unlikely case that this ever fails.
network: replace detailed netlink append messages with a single generic message
This commit is the first in the series, and they generally follow the same
idea: we had very detailed logging for message append operations which would
only fail either with some type error or intrinsic limit (and then they would
fail everywhere, so this would be noticed during development or in CI), or they
would fail with ENOMEM, in which case the exact location is not very interesting
since this is not repeatable.
I am in general in favour of detailed logging messages, because it helps with
diagnosis of errors, but I think case is an exception. Despite not being very
useful, those messages required a lot of effort, because they were customized
for each and every append operation. In fact some of the messages contained copy
errors. The text of the messages (since they are generally unique) also added up
to a considerable size.
This removes the log messages after each sd_netlink_message_append_*() in
fill_message_create() with a single line in netdev_create(). As described
above, we are just appending fields to a message, so those calls would almost
never fail.
A forgotten 'return' was added in one place.
$ size build/systemd-networkd{.0,}
text data bss dec hex filename 1878634 394016 36 2272686 22adae build/systemd-networkd.0 1842450 394080 36 2236566 222096 build/systemd-networkd
random-seed: hash together old seed and new seed before writing out file
If we're consuming an on-disk seed, we usually write out a new one after
consuming it. In that case, we might be at early boot and the randomness
could be rather poor, and the kernel doesn't guarantee that it'll use
the new randomness right away for us. In order to prevent the new
entropy from getting any worse, hash together the old seed and the new
seed, and replace the final bytes of the new seed with the hash output.
This way, entropy strictly increases and never regresses.
Fixes: https://github.com/systemd/systemd/issues/21983 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
$ udevadm test /devices/pci0000:00/0000:00:14.0/usb2/2-4/2-4.1/2-4.1.3
...
2-4.1.3: /usr/lib/udev/rules.d/40-libgphoto2.rules:9 Importing properties from results of builtin command 'usb_id'
2-4.1.3: /usr/lib/udev/rules.d/50-udev-default.rules:13 Skipping builtin 'usb_id' in IMPORT key
2-4.1.3: /usr/lib/udev/rules.d/50-udev-default.rules:13 Importing properties from results of builtin command 'hwdb --subsystem=usb'
2-4.1.3: hwdb modalias key: "usb:v17EFp3054:OneLink+ Giga"
2-4.1.3: /usr/lib/udev/rules.d/50-udev-default.rules:15 Importing properties from results of builtin command 'hwdb 'usb:v17efp3054''
2-4.1.3: No entry found from hwdb.
2-4.1.3: /usr/lib/udev/rules.d/50-udev-default.rules:15 Failed to run builtin 'hwdb 'usb:v17efp3054'': No data available
2-4.1.3: /usr/lib/udev/rules.d/50-udev-default.rules:52 MODE 0664
except that the existing one was done with uppercase digits and the full match pattern,
and the second one was done with lowercase digits.
With the previous commit we only have uppercase digits in our match patterns, so we can
drop the duplicate import. (Some other projects might have rules that used the lowercase
match patterns, and people might have some local rules that did that too. But the second
import was only added recently so I think it's better to rip off the bandaid quickly.)
hwdb: fix check for uppercasedness of match patterns
The check was added in 77547d5313ea916d2fb64ca5a8812734e9b50f92, but
it doesn't work as expected. Because the second part is wrapped in Optional(),
it would silently "succeed" when the lowercase digits were in the second part:
Empty files and empty strings seem to have triggered various
issues in the past so it seems they shouldn't be ignore by the
fuzzers just because fmemopen can't handle them.
Prompted by https://github.com/systemd/systemd/pull/21939#issuecomment-1003113669
meson: generate better arch defines for clang bpf compilation
The code assume that meson's cpu_family can be mapped directly to
'-D__<cpu_family>__'. This works in a surprising number of cases, but not for a
few architectures. PPC uses "powerpc", and RISC-V omits the trailing underscores.
ARM and RISC-V require a second define too.
Fixes #21900.
(I don't think this matters too much: we need *something* so that gnu/stubs.h
can be successfully included. But we don't actually call syscalls or depend too
much on the host environment, so things should be fine as long as we don't get
a compilation error.)
When the support for "synthetic errno" was added, we started truncating
the errno value to just the least significant byte. This is generally OK,
because errno values are defined up to ~130.
The docs don't really say what the maximum value is. But at least in principle
higher values could be added in the future. So let's stop truncating
the values needlessly.
The kernel (or libbpf?) have an error where they return 524 as an errno
value (https://bugzilla.redhat.com/show_bug.cgi?id=2036145). We would
confusingly truncate this to 12 (ENOMEM). It seems much nicer to let
strerror() give us "Unknown error 524" rather than to print the bogus
message about ENOMEM.
coredump: do not crash if we failed to acquire exe path
The COREDUMP_EXE attribute is "optional", i.e. we continue to process the
crash even if we didn't acquire it. The coredump generation code assumed
that it is always available:
#5 endswith at ../src/fundamental/string-util-fundamental.c:41
[ endswith() is called with NULL here, and an assertion fails. ]
#6 submit_coredump at ../src/coredump/coredump.c:823
#7 process_socket at ../src/coredump/coredump.c:1038
#8 run at ../src/coredump/coredump.c:1413
We use the exe path for loop detection, and also (ultimately) pass it to
dwfl_core_file_report(). The latter seems to be fine will NULL, so let's just
change our code to look at COMM, which should be more reliable anyway.
core/bpf: tighten handling of return values, improve messages
The code was written unidiomatically, using r as a boolean value, and
confusing errno and r in some places. AFAICS, there wasn't any actual
problem: even in the one place where errno was used instead of r, it would
almost certainly be initialized.
It seems that some libbpf functions set errno, while others return the
error, possibly encoded. Since there are almost no docs, the only way to
know is to read the code of the function. To make matters worse, there is
a global libbpf_mode which can be set to change the convention. With
LIBBPF_STRICT_DIRECT_ERRS in libbpf_mode, some functions set errno while others
return a negative error, and the only way to know is to read the code, except
that the split is now different. We currently don't set
LIBBPF_STRICT_DIRECT_ERRS, but even the possibility makes everything harder
to grok.
This is all very error-prone. Let's at least add some asserts to make sure that
the returned values are as expected.
Jan Janssen [Mon, 3 Jan 2022 09:41:45 +0000 (10:41 +0100)]
boot: Unify idx type handling
This replaces several inconsistent use of types and unsound
signed comparisons.
The added max entry count is just for paranoia. Anyone with that
many boot entries deserves a medal.
Jan Janssen [Sat, 1 Jan 2022 15:37:27 +0000 (16:37 +0100)]
boot: Use objcopy to align sections
Not aligning these can create gaps in the section table. Some
firmware does not handle this nicely resulting in secure boot
signature fails.
Using objcopy ensures that any new sections in the future will be
properly aligned.
projects / thirdparty / systemd.git / log
