With new LUKS2 header format it is possible to use Argon2 key derivation
function. This function is "memory-hard" hence keyslot unlocking can
potentially use a lot of RAM as this increases resistance to massively
parallel GPU based password cracking.
However, when multiple systemd-cryptsetup binaries run at the same
time it is very likely that system using Argon2 (e.g. Fedora 30)
will encounter memory-pressure during early boot, following OOM killing
spree.
This patch aims to lower the damage done by OOM killer and sets OOMScore
for systemd-cryptsetup units to 500. Hopefully OOM killer will then
shoot us down and leave rest of the system services alone.
6f177c7dc0 caused key file errors to immediately fail, which would make it hard to correct an issue due to e.g. a crypttab typo or a damaged key file.
Closes#11723.
As device units will be reloaded by systemd whenever the corresponding device generates a "changed" event, if the mount unit / cryptsetup service is wanted by its device unit, the former can be restarted by systemd unexpectedly after the user stopped them explicitly. It is not sensible at all and can be considered dangerous. Neither is the behaviour conventional (as `auto` in fstab should only affect behaviour on boot and `mount -a`) or ever documented at all (not even in systemd, see systemd.mount(5) and crypttab(5)).
First of all let's always log where the errors happen, and not in an
upper stackframe, in all cases. Previously we'd do this somethis one way
and sometimes another, which resulted in sometimes duplicate logging and
sometimes none.
When we cannot activate something due to bad password the kernel gives
us EPERM. Let's uniformly return this EAGAIN, so tha the next password
is tried. (previously this was done in most cases but not in all)
When we get EPERM let's also explicitly indicate that this probably
means the password is simply wrong.
Fixes: #11498
There should be no functional difference, except that the error message
is changd from "three or no arguments" to "zero or three arguments". Somehow
the inverted form always seemed strange.
umask() call is also dropped from run-generator. I think it wasn't dropped in
053254e3cb because the run generator was merged
around the same time.
Ideally, coccinelle would strip unnecessary braces too. But I do not see any
option in coccinelle for this, so instead, I edited the patch text using
search&replace to remove the braces. Unfortunately this is not fully automatic,
in particular it didn't deal well with if-else-if-else blocks and ifdefs, so
there is an increased likelikehood be some bugs in such spots.
I also removed part of the patch that coccinelle generated for udev, where we
returns -1 for failure. This should be fixed independently.
systemd already sets the umask (see e3b8d0637d). When
running under systemd, we don't need to set it. And when *not* running under
systemd, for example during development, there is no reason to override the user
config. Let's just drop those calls.
$ git grep -e 'umask\(' -l 'src/*generator*' |xargs perl -i -0pe 's|^[^\n]*umask\([^\n]+\n\n||gms'
All users of the macro (except for one, in serialize.c), use the macro in
connection with read_line(), so they must include fileio.h. Let's not play
libc games and require multiple header file to be included for the most common
use of a function.
The removal of def.h includes is not exact. I mostly went over the commits that
switch over to use read_line() and add def.h at the same time and reverted the
addition of def.h in those files.
For example, <luks.uuid>=/keyfile:LABEL="KEYFILE FS" previously wouldn't
work, because we truncated label at the first whitespace character,
i.e. LABEL="KEYFILE".
Instead of
Please enter passphrase for disk <disk-name>!
use
Please enter passphrase for disk <disk-name>:
which is more polite and matches Plymouth convention.
We are not the ones receiving an error here, but the ones generating it,
hence we shouldn't show it with %m, that's just confusing, as it
suggests we received an error from some other call.
Dracut has a support for unlocking encrypted drives with keyfile stored
on the external drive. This support is included in the generated initrd
only if systemd module is not included.
When systemd is used in initrd then attachment of encrypted drives is
handled by systemd-cryptsetup tools. Our generator has support for
keyfile, however, it didn't support keyfile on the external block
device (keydev).
This commit introduces basic keydev support. Keydev can be specified per
luks.uuid on the kernel command line. Keydev is automatically mounted
during boot and we look for keyfile in the keydev
mountpoint (i.e. keyfile path is prefixed with the keydev mount point
path). After crypt device is attached we automatically unmount
where keyfile resides.
Example:
rd.luks.key=70bc876b-f627-4038-9049-3080d79d2165=/key:LABEL=KEYDEV
This is a bit like the info link in most of GNU's --help texts, but we
don't do info but man pages, and we make them properly clickable on
terminal supporting that, because awesome.
I think it's generally advisable to link up our (brief) --help texts and
our (more comprehensive) man pages a bit, so this should be an easy and
straight-forward way to do it.
These lines are generally out-of-date, incomplete and unnecessary. With
SPDX and git repository much more accurate and fine grained information
about licensing and authorship is available, hence let's drop the
per-file copyright notice. Of course, removing copyright lines of others
is problematic, hence this commit only removes my own lines and leaves
all others untouched. It might be nicer if sooner or later those could
go away too, making git the only and accurate source of authorship
information.
This part of the copyright blurb stems from the GPL use recommendations:
https://www.gnu.org/licenses/gpl-howto.en.html
The concept appears to originate in times where version control was per
file, instead of per tree, and was a way to glue the files together.
Ultimately, we nowadays don't live in that world anymore, and this
information is entirely useless anyway, as people are very welcome to
copy these files into any projects they like, and they shouldn't have to
change bits that are part of our copyright header for that.
hence, let's just get rid of this old cruft, and shorten our codebase a
bit.
Double newlines (i.e. one empty lines) are great to structure code. But
let's avoid triple newlines (i.e. two empty lines), quadruple newlines,
quintuple newlines, …, that's just spurious whitespace.
It's an easy way to drop 121 lines of code, and keeps the coding style
of our sources a bit tigther.
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.
I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
This macro will read a pointer of any type, return it, and set the
pointer to NULL. This is useful as an explicit concept of passing
ownership of a memory area between pointers.
This takes inspiration from Rust:
https://doc.rust-lang.org/std/option/enum.Option.html#method.take
and was suggested by Alan Jenkins (@sourcejedi).
It drops ~160 lines of code from our codebase, which makes me like it.
Also, I think it clarifies passing of ownership, and thus helps
readability a bit (at least for the initiated who know the new macro)
This removes LOG_TARGET_SAFE. It's made redundant by the new
"prohibit-ipc" logging flag, as it used to have a similar effect: avoid
logging to the journal/syslog, i.e. any local services in order to avoid
deadlocks when we lock from PID 1 or its utility processes (such as
generators).
All previous users of LOG_TARGET_SAFE are switched over to the new
setting. This makes things a bit safer for all, as not even the
SYSTEMD_LOG_TARGET env var can be used to accidentally log to the
journal anymore in these programs.
It's a bit weird to test these strings after the fact instead of before.
Let's make sure that we don't even attempt the string escaping if the
strings are NULL.
Follow-up for #7688
Since systemd v236, several Arch users complained that
systemd-cryptsetup-generator exits with an OOM error and that it
prevents the boot from continuing.
Investigating the diff of cryptsetup-generator between v235 and v236 I
noticed that create_disk allowed for the `password` and `filtered`
variables to be NULL (they're handled with `strempty()`) but not their
`*_escaped` versions, and returned OOM errors in those cases.
Fix this by checking that the input string is non-NULL before deciding
that `specifier_escape` had an OOM error.
I could not test this fix myself, but some users have reported success.
Downstream bug: https://bugs.archlinux.org/task/56733
Let's replace usage of fputc_unlocked() and friends by __fsetlocking(f,
FSETLOCKING_BYCALLER). This turns off locking for the entire FILE*,
instead of doing individual per-call decision whether to use normal
calls or _unlocked() calls.
This has various benefits:
1. It's easier to read and easier not to forget
2. It's more comprehensive, as fprintf() and friends are covered too
(as these functions have no _unlocked() counterpart)
3. Philosophically, it's a bit more correct, because it's more a
property of the file handle really whether we ever pass it on to another
thread, not of the operations we then apply to it.
This patch reworks all pieces of codes that so far used fxyz_unlocked()
calls to use __fsetlocking() instead. It also reworks all places that
use open_memstream(), i.e. use stdio FILE* for string manipulations.
Note that this in some way a revert of 4b61c87511.
Let's rename escaped_name to disk_path since this is an actual content
that pointer refers to. It is either path to encrypted block device
or path to encrypted image file.
Also drop redundant function disk_major_minor(). src is always set, and
it always points to either encrypted block device path (or symlink to
such device) or to encrypted image. In case it is set to device path
there is no need to reset it to /dev/block/major:minor symlink since
those paths are equivalent.
Some ask-password agents (e.g. clevis-luks-askpass) use Id option from
/run/systemd/ask-password/ask* file in order to obtain the password for
the device.
Id option should be in the following format,
e.g. Id=subsystem:data. Where data part is supposed to identify object
that ask-password query is done for. Since
e51b9486d1 this field has format
Id=cryptsetup:/dev/block/major:minor when systemd-cryptsetup is
unlocking encrypted block device. However, crypttab also supports
encrypted image files in which case we usually set data part of Id to
"vol on mountpoint". This is unexpected and actually breaks network
based device encryption as implemented by clevis.
Example:
$ cat /etc/crypttab
clevis-unlocked /clevis-test-disk-image none luks,_netdev
$ systemctl start 'systemd-cryptsetup@clevis\x2dunlocked.service'
$ grep Id /run/systemd/ask-password/ask*
Before:
$ Id=cryptsetup:clevis-unlocked on /clevis-test-disk-image-mnt
After:
$ Id=cryptsetup:/clevis-test-disk-image
