Even with the new keyed hash table journal feature: if an attacker
manages to get access to the journal file id it could synthesize records
that result in hash collisions. Let's rotate automatically when we
notice that, so that a new journal file ID is generated, our performance
is restored and the attacker has to guess a new file ID before being
able to trigger the issue again.
That said, untrusted peers should never get access to journal files in
the first case...
This adds a new (incompatible) feature to journal files: if enabled the
hash function used for the hash tables is no longer jenkins hash with a
zero key, but siphash keyed by the file uuid that is included in the
file header anyway. This should make our hash tables more robust against
collision attacks, as long as the attacker has no read access to the
journal files. We switch from jenkins to siphash simply because it's
more well-known and we standardize for the rest of our codebase onto it.
This is hardening in order to make collision attacks harder for clients
that can forge log messages but have no read access to the logs. It has
no effect on clients that have read access.
The object flags field is a bitmask, hence don't sloppily define
_OBJECT_COMPRESSED_MAX as one mor than the previous flag. That worked OK
as long as we only had two flags, but will fall apart as soon as we have
three. Let's fix this.
(It's kinda sloppy how the string table is built here, as it will be
quite sparse as soon as we have more enum entries, but let's keep it for
now.)
These lines are generally out-of-date, incomplete and unnecessary.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.
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.
The advantage is that is the name is mispellt, cpp will warn us.
$ git grep -Ee "conf.set\('(HAVE|ENABLE)_" -l|xargs sed -r -i "s/conf.set\('(HAVE|ENABLE)_/conf.set10('\1_/"
$ git grep -Ee '#ifn?def (HAVE|ENABLE)' -l|xargs sed -r -i 's/#ifdef (HAVE|ENABLE)/#if \1/; s/#ifndef (HAVE|ENABLE)/#if ! \1/;'
$ git grep -Ee 'if.*defined\(HAVE' -l|xargs sed -i -r 's/defined\((HAVE_[A-Z0-9_]*)\)/\1/g'
$ git grep -Ee 'if.*defined\(ENABLE' -l|xargs sed -i -r 's/defined\((ENABLE_[A-Z0-9_]*)\)/\1/g'
+ manual changes to meson.build
squash! build-sys: use #if Y instead of #ifdef Y everywhere
v2:
- fix incorrect setting of HAVE_LIBIDN2
Note that numbers 0 and -1 are both replaced with OBJECT_UNUSED,
because they are treated the same everywhere (e.g. type_to_context()
translates them both to 0).
Add liblz4 as an optional dependency when requested with --enable-lz4,
and use it in preference to liblzma for journal blob and coredump
compression. To retain backwards compatibility, XZ is used to
decompress old blobs.
Things will function correctly only with lz4-119.
Based on the benchmarks found on the web, lz4 seems to be the best
choice for "quick" compressors atm.
For pkg-config status, see http://code.google.com/p/lz4/issues/detail?id=135.
GCC manual states that "For an enum, struct or union type, you may
specify attributes either between the enum, struct or union tag and
the name of the type, or just past the closing curly brace of the
definition. The former syntax is preferred." This means that the
attribute should not be located before 'struct'. Putting it between
'struct' and the name seems cluttered. Putting it at the end seems
most readable.
This avoids clang warnings.
Let's clean up our terminology a bit. New terminology:
FSS = Forward Secure Sealing
FSPRG = Forward Secure Pseudo-Random Generator
FSS is the combination of FSPRG and a HMAC.
Sealing = process of adding authentication tags to the journal.
Verification = process of checking authentication tags to the journal.
Sealing Key = The key used for adding authentication tags to the journal.
Verification Key = The key used for checking authentication tags of the journal.
Key pair = The pair of Sealing Key and Verification Key
Internally, the Sealing Key is the combination of the FSPRG State plus
change interval/start time.
Internally, the Verification Key is the combination of the FSPRG Seed
plus change interval/start time.
This adds forward-secure authentication of journal files. This patch
includes key generation as well as tagging of journal files,
Verification of journal files will be added in a later patch.
#pragma once has been "un-deprecated" in gcc since 3.3, and is widely supported
in other compilers.
I've been using and maintaining (rebasing) this patch for a while now, as
it annoyed me to see #ifndef fooblahfoo, etc all over the place,
almost arrogant about the annoyance of having to define all these names to
perform a commen but neccicary functionality, when a completely superior
alternative exists.
I havn't sent it till now, cause its kindof a style change, and it is bad
voodoo to mess with style that has been established by more established
editors. So feel free to lambast me as a crazy bafoon.
v2 - preserve externally used headers
Previously, when the main data hash table grows too full the performance
simply started to decrease drastically. Instead, now simply rotate to a
new journal file as the hash table gets to full, so that we can start
with a new fresh empty hash table.
We finally got the OK from all contributors with non-trivial commits to
relicense systemd from GPL2+ to LGPL2.1+.
Some udev bits continue to be GPL2+ for now, but we are looking into
relicensing them too, to allow free copy/paste of all code within
systemd.
The bits that used to be MIT continue to be MIT.
The big benefit of the relicensing is that closed source code may now
link against libsystemd-login.so and friends.
