* Drop mac_selinux_use() condition from mac_selinux_free(): if the
passed pointer holds memory we want to free it even if SELinux is
disabled
* Drop NULL-check cause man:freecon(3) states that freecon(NULL) is a
well-defined NOP
* Assert that on non-SELinux builds the passed pointer is always NULL,
to avoid memory leaks
Previously we'd used the existance of a specific AF_UNIX socket in the
abstract namespace as lock for disabling lookup recursions. (for
breaking out of the loop: userdb synthesized from nss → nss synthesized
from userdb → userdb synthesized from nss → …)
I did it like that because it promised to work the same both in static
and in dynmically linked environments and is accessible easily from any
programming language.
However, it has a weakness regarding reuse attacks: the socket is
securely hashed (siphash) from the thread ID in combination with the
AT_RANDOM secret. Thus it should not be guessable from an attacker in
advance. That's only true if a thread takes the lock only once and
keeps it forever. However, if a thread takes and releases it multiple
times an attacker might monitor that and quickly take the lock
after the first iteration for follow-up iterations.
It's not a big issue given that userdb (as the primary user for this)
never released the lock and we never made the concept a public
interface, and it was only included in one release so far, but it's
something that deserves fixing. (moreover it's a local DoS only, only
permitting to disable native userdb lookups)
With this rework the libnss_systemd.so.2 module will now export two
additional symbols. These symbols are not used by glibc, but can be used
by arbitrary programs: one can be used to disable nss-systemd, the other
to check if it is currently disabled.
The lock is per-thread. It's slightly less pretty, since it requires
people to manually link against C code via dlopen()/dlsym(), but it
should work safely without the aforementioned weakness.
This just adds a _cleanup_ helper call encapsulating dlclose().
This also means libsystemd-shared is linked against libdl now. I don't
think this is much of an issue, since libdl is part of glibc anyway, and
anything from exotic. It's not an optional part of the OS (think: NSS
requires dynamic linking), hence this pulls in no deps and is almost
certainly loaded into all process' memory anyway.
[zj: use DEFINE_TRIVIAL_CLEANUP_FUNC().]
This reverts commit 53aa85af24.
The reason is that that patch changes the dbus api to be different than
the types declared by introspection api.
Replaces #16122.
This reverts commit 097537f07a.
At least Fedora and Debian have already reverted this at the distro
level because it causes more problems than it solves. Arch is debating
reverting it as well [0] but would strongly prefer that this happens
upstream first. Fixes#15188.
[0] https://bugs.archlinux.org/task/66458
If an autostart file for GNOME has a phase specified, then this implies
it is a session service that needs to be started at a specific time.
We have no way of handling the ordering, and while it does make sense
to explicitly hide these services with X-systemd-skip, there is no point
in even trying to handle them.
Since #15533 we didn't create the mount point for selinuxfs anymore.
Before it we created it twice because we mount selinuxfs twice: once the
superblock, and once we remount its bind mound read-only. The second
mkdir would mean we'd chown() the host version of selinuxfs (since
there's only one selinuxfs superblock kernel-wide).
The right time to create mount point point is once: before we mount the
selinuxfs. But not a second time for the remount.
Fixes: #16032
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)
Access to bit fields is less efficient, and since the Manager is a singleton,
a byte or two of space in the structure doesn't matter at all. (And in this
particular case, because of alignment issues, we wouldn't save anything
anyway.)
The key macros added in commit 6fe95d3020 look strange at first sight.
Add a comment with just the tablet name after each line, so that it's
obvious that these lines address device-specific issues of the EFI
firmware, and not broken/old code.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
