* Implement FCrDNS and other DNS features
* Redesign DNS cache and methods
* Fix DNS cache
* Rename regexSafe arg
* Alter verifyFCrDNS(addr) behaviour
* Remove unused dnsCache field from Server struct
* Upd expressions docs
* Update docs/docs/CHANGELOG.md
Signed-off-by: Xe Iaso <me@xeiaso.net>
* refactor(dns): simplify FCrDNS logging
* docs: clarify verifyFCrDNS behavior
Add a note to the documentation for `verifyFCrDNS` to clarify that it returns true when no PTR records are found for the given IP address.
* fix(dns): Improve FCrDNS error handling and tests
The `VerifyFCrDNS` function previously ignored errors returned from reverse DNS lookups. This could lead to incorrect passes when a DNS failure (other than a simple 'not found') occurred. This change ensures that any error from a reverse lookup will cause the FCrDNS check to fail.
The test suite for FCrDNS has been updated to reflect this change. The mock DNS lookups now simulate both 'not found' errors and other generic DNS errors. The test cases have been updated to ensure that the function behaves correctly in both scenarios, resolving a situation where two test cases were effectively duplicates.
* docs: Update FCrDNS documentation and spelling
Corrected a typo in the `verifyFCrDNS` function documentation.
Additionally, updated the spelling exception list to include new terms and remove redundant entries.
* chore: update spelling
Signed-off-by: Xe Iaso <me@xeiaso.net>
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Signed-off-by: Xe Iaso <me@xeiaso.net>
Co-authored-by: Xe Iaso <me@xeiaso.net>
* feat(lib/policy/expressions): add system load average to bot expression inputs
This lets Anubis dynamically react to system load in order to
increase and decrease the required level of scrutiny. High load? More
scrutiny required. Low load? Less scrutiny required.
* docs: spell system correctly
Signed-off-by: Xe Iaso <me@xeiaso.net>
* Update metadata
check-spelling run (pull_request) for Xe/load-average
Signed-off-by: check-spelling-bot <check-spelling-bot@users.noreply.github.com>
on-behalf-of: @check-spelling <check-spelling-bot@check-spelling.dev>
* fix(default-config): don't enable low load average feature by default
Signed-off-by: Xe Iaso <me@xeiaso.net>
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Signed-off-by: Xe Iaso <me@xeiaso.net>
Signed-off-by: check-spelling-bot <check-spelling-bot@users.noreply.github.com>
Signed-off-by: Xe Iaso <xe.iaso@techaro.lol>
This seems counter-intuitive at first glance, but let me cook.
One of the problems with Anubis is that the rule matching is super
deterministic. This means that attackers can figure out what patterns
they are hitting and change things to bypass them.
The randInt function lets you have rulesets behave nondeterministically.
This is a very easy way to hang yourself, but can be great to
psychologically mess with scraper operators. Consider this rule:
```yaml
- name: deny-lightpanda-sometimes
action: DENY
expression:
all:
- userAgent.matches("LightPanda")
- randInt(16) >= 4
```
It would match about 75% of the time.
Signed-off-by: Xe Iaso <me@xeiaso.net>
* feat(lib/policy): add support for CEL checkers
This adds the ability for administrators to use Common Expression
Language[0] (CEL) for more advanced check logic than Anubis previously
offered.
These can be as simple as:
```yaml
- name: allow-api-routes
action: ALLOW
expression:
and:
- '!(method == "HEAD" || method == "GET")'
- path.startsWith("/api/")
```
or get as complicated as:
```yaml
- name: allow-git-clients
action: ALLOW
expression:
and:
- userAgent.startsWith("git/") || userAgent.contains("libgit") || userAgent.startsWith("go-git") || userAgent.startsWith("JGit/") || userAgent.startsWith("JGit-")
- >
"Git-Protocol" in headers && headers["Git-Protocol"] == "version=2"
```
Internally these are compiled and evaluated with cel-go[1]. This also
leaves room for extensibility should that be desired in the future. This
will intersect with #338 and eventually intersect with TLS fingerprints
as in #337.
[0]: https://cel.dev/
[1]: https://github.com/google/cel-go
Signed-off-by: Xe Iaso <me@xeiaso.net>
* feat(data/apps): add API route allow rule for non-HEAD/GET
Signed-off-by: Xe Iaso <me@xeiaso.net>
* docs: document expression syntax
Signed-off-by: Xe Iaso <me@xeiaso.net>
* fix: fixes in review
Signed-off-by: Xe Iaso <me@xeiaso.net>
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Signed-off-by: Xe Iaso <me@xeiaso.net>
