Files
smallwebwaf/internal/proxy/biased.go
T
clawbot ca787985f8
check / check (push) Waiting to run
AbuseIPDB scores for clients that committed an offence, within a daily budget (closes #105)
With SWWAF_ABUSEIPDB_KEY set, a client whose history counts an offence
(a broken limit, a ban rule's match or a block rule's refusal, counted
by kind) is checked in the background, at most
SWWAF_ABUSEIPDB_DAILY_BUDGET checks a day, the count kept in
reputation.json. A client, an IPv4 address or an IPv6 /64, is checked by
the address it sent from, and its score serves all its addresses. A
score at or over SWWAF_ABUSEIPDB_MIN_SCORE is a hit for
SWWAF_REPUTATION_ACTION, logged as abuseipdb and alerted with its score.
A failure or the used-up budget gives no score and raises
source_failure. The key goes only in the Key header.

Judgement call: the budget's day is UTC; AbuseIPDB documents no reset time.
Judgement call: each check sent spends budget; a minute's pause after a failure.

Model: opus-5-5
2026-10-07 22:47:06 +02:00

120 lines
4.4 KiB
Go

package proxy
import (
"sneak.berlin/go/smallwebwaf/internal/config"
)
// whole is the percentage of each limit a client gets when no biased
// threshold lowers its limits.
const whole = 100
// percentage is a client's limit percentage for the rate limits or for
// the byte limits, as the biased thresholds give it, and the setting that
// gave it: "" with whole when none lowers that kind of limit.
type percentage struct {
percent int64
setting string
}
// biasedThresholdsSet reports whether a biased threshold can lower a
// client's limits: one of its lists is not empty,
// SWWAF_UNKNOWN_LIMIT_PERCENT is below 100, or SWWAF_ASN_LIMIT_PERCENT_URL
// is set. The client's lookup is then needed before its request goes on.
func biasedThresholdsSet(cfg *config.Config) bool {
return len(cfg.ASNLimitPercent) > 0 || len(cfg.CountryLimitPercent) > 0 ||
len(cfg.ASNBytesPercent) > 0 || len(cfg.CountryBytesPercent) > 0 ||
cfg.UnknownLimitPercent < whole || cfg.ASNLimitPercentURL != ""
}
// limitPercentages returns the client's limit percentages, for the rate
// limits and for the byte limits, by its AS number and country as looked
// up, each "" when unknown, and the blocklists, DNSBL zones and AbuseIPDB
// that list it. Each is the lowest of those the settings give it, the
// first of them in the order below when several are lowest: the
// percentage SWWAF_ASN_LIMIT_PERCENT gives its AS number, the one the file
// SWWAF_ASN_LIMIT_PERCENT_URL names gives it, the one
// SWWAF_COUNTRY_LIMIT_PERCENT gives its country, for a client without a
// country, SWWAF_UNKNOWN_LIMIT_PERCENT, for a client a blocklist lists,
// the percentage of SWWAF_BLOCKLIST_ACTION while it is limit, and for a
// client a DNSBL zone's verdict lists, or whose AbuseIPDB score is a hit,
// the percentage of SWWAF_REPUTATION_ACTION while it is limit. For the
// byte limits, SWWAF_ASN_BYTES_PERCENT and SWWAF_COUNTRY_BYTES_PERCENT
// take the place of the first three for an AS number or a country they
// list.
func (rq *request) limitPercentages() (percentage, percentage) {
cfg := rq.h.config
asn, country := rq.line.ASN, rq.line.Country
unknown := percentage{percent: whole}
if country == "" {
unknown = percentage{cfg.UnknownLimitPercent, "SWWAF_UNKNOWN_LIMIT_PERCENT"}
}
fetched := percentage{percent: whole}
if percent, listed := rq.h.lists.ASNLimitPercent(asn); listed {
fetched = percentage{percent, "SWWAF_ASN_LIMIT_PERCENT_URL"}
}
blocklisted := percentage{percent: whole}
if rq.blocklisted && cfg.BlocklistAction == "limit" {
blocklisted = percentage{cfg.BlocklistLimitPercent, "SWWAF_BLOCKLIST_ACTION"}
}
reputationListed := percentage{percent: whole}
if (rq.dnsblListed || rq.abuseIPDBHit) && cfg.ReputationAction == "limit" {
reputationListed = percentage{cfg.ReputationLimitPercent, "SWWAF_REPUTATION_ACTION"}
}
asnRequests := lowest(given(cfg.ASNLimitPercent, asn, "SWWAF_ASN_LIMIT_PERCENT"),
fetched)
countryRequests := given(cfg.CountryLimitPercent, country,
"SWWAF_COUNTRY_LIMIT_PERCENT")
asnBytes, countryBytes := asnRequests, countryRequests
if _, listed := cfg.ASNBytesPercent[asn]; listed {
asnBytes = given(cfg.ASNBytesPercent, asn, "SWWAF_ASN_BYTES_PERCENT")
}
if _, listed := cfg.CountryBytesPercent[country]; listed {
countryBytes = given(cfg.CountryBytesPercent, country, "SWWAF_COUNTRY_BYTES_PERCENT")
}
return lowest(asnRequests, countryRequests, unknown, blocklisted, reputationListed),
lowest(asnBytes, countryBytes, unknown, blocklisted, reputationListed)
}
// given returns the percentage percents, the setting named setting, gives
// code, an AS number or a country, or whole when it does not list code.
func given(percents map[string]int64, code, setting string) percentage {
percent, listed := percents[code]
if !listed {
return percentage{percent: whole}
}
return percentage{percent, setting}
}
// lowest returns the lowest of percentages below whole, the first of them
// when several are lowest, or whole when none is below it.
func lowest(percentages ...percentage) percentage {
low := percentage{percent: whole}
for _, p := range percentages {
if p.percent < low.percent {
low = p
}
}
return low
}
// logged returns p as the log line and the notes of a ban give it: its
// percent and setting, or nil and "" for whole, which they leave out.
func (p percentage) logged() (*int64, string) {
if p.percent == whole {
return nil, ""
}
return &p.percent, p.setting
}