By settings AI_ADDRCONFIG in hints we cannot for example resolve "localhost"
when the local machine only has a loopback interface. This seems like an
unnecessary restriction, drop it.
Inspired by https://bugzilla.redhat.com/show_bug.cgi?id=1839007.
Like it's customary in our codebase bus_error_message() internally takes
abs() of the passed error anyway, hence no need to explicitly negate it.
We mostly got this right, but in too many cases we didn't. Fix that.
For discussion around this see: https://pagure.io/fedora-workstation/issue/82
Recovery keys for homed are very similar to regular passwords, except
that they are exclusively generated by the computer, and not chosen by
the user. The idea is that they are printed or otherwise stored
externally and not what users type in every day.
Taking inspiration from Windows and MacOS this uses 256bit keys. We
format them in 64 yubikey modhex characters, in groups of 8 chars
separated by dashes.
Why yubikey modhex? modhex only uses characters that are are located at
the same place in western keyboard designs. This should reduce the
chance for incorrect inputs for a major chunk of our users, though
certainly not all. This is particular relevant during early boot and
recovery situations, where there's a good chance the keyboard mapping is
not correctly set up.
let's make sure we collect the right error code from errno, otherwise
we'll see EPERM (i.e. error 1) for all errors readv() returns (since it
returns -1 on error), including EAGAIN.
This is definitely backport material.
A fix-up for 3691bcf3c5.
Fixes: #16699
We never return anything higher than 63, so using "long unsigned"
as the type only confused the reader. (We can still use "long unsigned"
and safe_atolu() to parse the kernel file.)
We'd try to map a zero-byte buffer from a NULL pointer, which is undefined behaviour.
src/systemd/src/libsystemd/sd-bus/bus-message.c:3161:60: runtime error: applying zero offset to null pointer
#0 0x7f6ff064e691 in find_part /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-message.c:3161:60
#1 0x7f6ff0640788 in message_peek_body /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-message.c:3283:16
#2 0x7f6ff064e8db in enter_struct_or_dict_entry /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-message.c:3967:21
#3 0x7f6ff06444ac in bus_message_enter_struct /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-message.c:4009:13
#4 0x7f6ff0641dde in sd_bus_message_enter_container /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-message.c:4136:21
#5 0x7f6ff0619874 in sd_bus_message_dump /work/build/../../src/systemd/src/libsystemd/sd-bus/bus-dump.c:178:29
#6 0x4293d9 in LLVMFuzzerTestOneInput /work/build/../../src/systemd/src/fuzz/fuzz-bus-message.c:39:9
#7 0x441986 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/libfuzzer/FuzzerLoop.cpp:558:15
#8 0x44121e in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*) /src/libfuzzer/FuzzerLoop.cpp:470:3
#9 0x443164 in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::__1::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) /src/libfuzzer/FuzzerLoop.cpp:770:7
#10 0x4434bc in fuzzer::Fuzzer::Loop(std::__1::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) /src/libfuzzer/FuzzerLoop.cpp:799:3
#11 0x42d2bc in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/libfuzzer/FuzzerDriver.cpp:846:6
#12 0x42978a in main /src/libfuzzer/FuzzerMain.cpp:19:10
#13 0x7f6fef13c82f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
#14 0x407808 in _start (out/fuzz-bus-message+0x407808)
Prompted by the discussion on #16110, let's migrate more code to
fd_wait_for_event().
This only leaves 7 places where we call into poll()/poll() directly in
our entire codebase. (one of which is fd_wait_for_event() itself)
poll() sets POLLNVAL inside of the poll structures if an invalid fd is
passed. So far we generally didn't check for that, thus not taking
notice of the error. Given that this specific kind of error is generally
indication of a programming error, and given that our code is embedded
into our projects via NSS or because people link against our library,
let's explicitly check for this and convert it to EBADF.
(I ran into a busy loop because of this missing check when some of my
test code accidentally closed an fd it shouldn't close, so this is a
real thing)
Each of bus_set_address_{user,system} had two users, and each of the two users
would set the internal flag manually. We should do that internally in the
functions instead.
While at it, only set the flag when setting the address is actually successful.
This doesn't change anything for current users, but it seems more correct.
Those are fairly trivial to reimplement, but any non-trivial user of sd-bus
is likely to need them. So let's expose them to save everyone the trouble.
I'm keeping the internal functions and making the public ones thin wrappers,
because for the internal uses we don't need the additional asserts, and also we
can't expose _pure_ annotation easily, and dropping it would likely make the
compiled code a bit less efficient.
In the linked reproducer, m->fields_size == 0, and we calculate ri == -1, which
of course doesn't end well. Skip the whole calculation if m->fields_size == 0,
and also check that we don't go negative even if it is non-zero.
Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=19446 and #15583.
When set, the offset specified for the vtable entry is passed to the
handler as-is, and is not added to the userdata pointer. This is useful
in case methods/properties are mixed on the same vtable, that expect to
operate relative to some object in memory and that expect pointers to
absolute memory, or that just want a number passed.
We always need to make them unions with a "struct cmsghdr" in them, so
that things properly aligned. Otherwise we might end up at an unaligned
address and the counting goes all wrong, possibly making the kernel
refuse our buffers.
Also, let's make sure we initialize the control buffers to zero when
sending, but leave them uninitialized when reading.
Both the alignment and the initialization thing is mentioned in the
cmsg(3) man page.
We need to use the CMSG_SPACE() macro to size the control buffers, not
CMSG_LEN(). The former is rounded up to next alignment boundary, the
latter is not. The former should be used for allocations, the latter for
encoding how much of it is actually initialized. See cmsg(3) man page
for details about this.
Given how confusing this is, I guess we don't have to be too ashamed
here, in most cases we actually did get this right.
With cgroup v2 the cgroup freezer is implemented as a cgroup
attribute called cgroup.freeze. cgroup can be frozen by writing "1"
to the file and kernel will send us a notification through
"cgroup.events" after the operation is finished and processes in the
cgroup entered quiescent state, i.e. they are not scheduled to
run. Writing "0" to the attribute file does the inverse and process
execution is resumed.
This commit exposes above low-level functionality through systemd's DBus
API. Each unit type must provide specialized implementation for these
methods, otherwise, we return an error. So far only service, scope, and
slice unit types provide the support. It is possible to check if a
given unit has the support using CanFreeze() DBus property.
Note that DBus API has a synchronous behavior and we dispatch the reply
to freeze/thaw requests only after the kernel has notified us that
requested operation was completed.
Let's be extra careful whenever we return from recvmsg() and see
MSG_CTRUNC set. This generally means we ran into a programming error, as
we didn't size the control buffer large enough. It's an error condition
we should at least log about, or propagate up. Hence do that.
This is particularly important when receiving fds, since for those the
control data can be of any size. In particular on stream sockets that's
nasty, because if we miss an fd because of control data truncation we
cannot recover, we might not even realize that we are one off.
(Also, when failing early, if there's any chance the socket might be
AF_UNIX let's close all received fds, all the time. We got this right
most of the time, but there were a few cases missing. God, UNIX is hard
to use)
ubsan complains that we add an offset to a NULL ptr here in some cases.
Which isn't really a bug though, since we only use it as the end
condition for a for loop, but we can still fix it...
Fixes: #15522
A warning is emitted from sd_bus_message_{get,set}_priority. Those functions
are exposed by pystemd, so we have no easy way of checking if anything is
calling them.
Just making the functions always return without doing anything would be an
option, but then we could leave the caller with an undefined variable. So I
think it's better to make the functions emit a warnings and return priority=0
in the get operation.
Consumers of the sd-bus convenience API can't make convenience
helpers of their own without va_list variants.
This commit is a mechanical change splitting out the existing function
bodies into bare va_list variants having a 'v' suffixed to the names.
The original functions now simply create the va_list before forwarding
the call on to the va_list variant, and the va_list variants dispense
with those steps.
sd_bus_reply_method_errno already does the same two checks
(sd_bus_error_is_set(error), r < 0) internally. But it did them in opposite
order. The effect is the same, because sd_bus_reply_method_errno falls back to
sd_bus_reply_method_error, but it seems inelegant. So let's simplify
bus_maybe_reply_error() to offload the job fully to sd_bus_reply_method_errno().
No functional change.
In those functions where bus defaults to the m->bus, we should also
resolve the magic parameters. And if neither called with bus=NULL
and an unattached message, return properly instead of crashing in assert
later.
Lennart Poettering