Merge branch 'main' into Xe/doc-disabling-jit

Signed-off-by: Xe Iaso <xe.iaso@techaro.lol>

.github/actions/spelling/allow.txt

@@ -29,3 +29,8 @@ Prolocation
 Necron
 Stargate
 FFXIV
+uvensys
+de
+resourced
+envoyproxy
+unipromos

.github/workflows/ssh-ci.yml

@@ -12,14 +12,15 @@ permissions:
 jobs:
   ssh:
     if: github.repository == 'TecharoHQ/anubis'
-    runs-on: alrest-techarohq
+    #runs-on: alrest-techarohq
+    runs-on: ubuntu-latest
     strategy:
       matrix:
         host:
           - riscv64
           - ppc64le
-          - aarch64-4k
-          - aarch64-16k
+          #- aarch64-4k
+          #- aarch64-16k
     steps:
       - name: Checkout code
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

README.md

@@ -26,6 +26,12 @@ Anubis is brought to you by sponsors and donors like:
 
 ### Gold Tier
 
+<a href="https://www.unipromos.com/?utm_campaign=github&utm_medium=referral&utm_content=anubis">
+  <img src="./docs/static/img/sponsors/unipromos.webp" alt="Unipromos" height="64" />
+</a>
+<a href="https://uvensys.de/?utm_campaign=github&utm_medium=referral&utm_content=anubis">
+  <img src="./docs/static/img/sponsors/uvensys.webp" alt="Uvensys" height="64">
+</a>
 <a href="https://distrust.co?utm_campaign=github&utm_medium=referral&utm_content=anubis">
   <img src="./docs/static/img/sponsors/distrust-logo.webp" alt="Distrust" height="64">
 </a>

cmd/anubis/main.go

@@ -418,8 +418,8 @@ func main() {
 
 	var redirectDomainsList []string
 	if *redirectDomains != "" {
-		domains := strings.Split(*redirectDomains, ",")
-		for _, domain := range domains {
+		domains := strings.SplitSeq(*redirectDomains, ",")
+		for domain := range domains {
 			_, err = url.Parse(domain)
 			if err != nil {
 				log.Fatalf("cannot parse redirect-domain %q: %s", domain, err.Error())

cmd/robots2policy/main.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"os"
 	"regexp"
+	"slices"
 	"strings"
 
 	"github.com/TecharoHQ/anubis/lib/config"
@@ -210,11 +211,8 @@ func parseRobotsTxt(input io.Reader) ([]RobotsRule, error) {
 
 	// Mark blacklisted user agents (those with "Disallow: /")
 	for i := range rules {
-		for _, disallow := range rules[i].Disallows {
-			if disallow == "/" {
-				rules[i].IsBlacklist = true
-				break
-			}
+		if slices.Contains(rules[i].Disallows, "/") {
+			rules[i].IsBlacklist = true
 		}
 	}
 

cmd/robots2policy/robots2policy_test.go

@@ -158,8 +158,8 @@ func TestDataFileConversion(t *testing.T) {
 			}
 
 			if strings.ToLower(*outputFormat) == "yaml" {
-				var actualData []interface{}
-				var expectedData []interface{}
+				var actualData []any
+				var expectedData []any
 
 				err = yaml.Unmarshal(actualOutput, &actualData)
 				if err != nil {
@@ -178,8 +178,8 @@ func TestDataFileConversion(t *testing.T) {
 					t.Errorf("Output mismatch for %s\nExpected:\n%s\n\nActual:\n%s", tc.name, expectedStr, actualStr)
 				}
 			} else {
-				var actualData []interface{}
-				var expectedData []interface{}
+				var actualData []any
+				var expectedData []any
 
 				err = json.Unmarshal(actualOutput, &actualData)
 				if err != nil {
@@ -419,6 +419,6 @@ Disallow: /`
 
 // compareData performs a deep comparison of two data structures,
 // ignoring differences that are semantically equivalent in YAML/JSON
-func compareData(actual, expected interface{}) bool {
+func compareData(actual, expected any) bool {
 	return reflect.DeepEqual(actual, expected)
 }

data/crawlers/_allow-good.yaml

@@ -8,4 +8,5 @@
 - import: (data)/crawlers/marginalia.yaml
 - import: (data)/crawlers/mojeekbot.yaml
 - import: (data)/crawlers/commoncrawl.yaml
+- import: (data)/crawlers/wikimedia-citoid.yaml
 - import: (data)/crawlers/yandexbot.yaml

data/crawlers/wikimedia-citoid.yaml

@@ -0,0 +1,18 @@
+# Wikimedia Foundation citation services
+# https://www.mediawiki.org/wiki/Citoid
+
+- name: wikimedia-citoid
+  user_agent_regex: "Citoid/WMF"
+  action: ALLOW
+  remote_addresses: [
+    "208.80.152.0/22",
+    "2620:0:860::/46",
+  ]
+
+- name: wikimedia-zotero-translation-server
+  user_agent_regex: "ZoteroTranslationServer/WMF"
+  action: ALLOW
+  remote_addresses: [
+    "208.80.152.0/22",
+    "2620:0:860::/46",
+  ]

docs/docs/CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- fix: prevent nil pointer panic in challenge validation when threshold rules match during PassChallenge (#1463)
 - Instruct reverse proxies to not cache error pages.
 - Fixed mixed tab/space indentation in Caddy documentation code block
 

docs/docs/admin/environments/haproxy.mdx

@@ -48,6 +48,8 @@ This simply enables SSL offloading, sets some useful and required headers and ro
 
 Due to the fact that HAProxy can decode JWT, we are able to verify the Anubis token directly in HAProxy and route the traffic to the specific backends ourselves.
 
+Mind that rule logic to allow Git HTTP and other legit bot traffic to bypass is delegated from Anubis to HAProxy then. If required, you should implement any whitelisting in HAProxy using `acl_anubis_ignore` yourself.
+
 In this example are three applications behind one HAProxy frontend. Only App1 and App2 are secured via Anubis; App3 is open for everyone. The path `/excluded/path` can also be accessed by anyone.
 
 ```mermaid

docs/docs/admin/environments/kubernetes.mdx

@@ -130,3 +130,52 @@ Then point your Ingress to the Anubis port:
               # diff-add
               name: anubis
 ```
+
+## Envoy Gateway
+
+If you are using envoy-gateway, the `X-Real-Ip` header is not set by default, but Anubis does require it. You can resolve this by adding the header, either on the specific `HTTPRoute` where Anubis is listening, or on the `ClientTrafficPolicy` to apply it to any number of Gateways:
+
+HTTPRoute:
+```yaml
+apiVersion: gateway.networking.k8s.io/v1
+kind: HTTPRoute
+metadata:
+  name: app-route
+spec:
+  hostnames: ["app.domain.tld"]
+  parentRefs:
+    - name: envoy-external
+      namespace: network
+      sectionName: https
+  rules:
+    - backendRefs:
+        - identifier: *app
+          port: anubis
+      filters:
+        - type: RequestHeaderModifier
+          requestHeaderModifier:
+            set:
+              - name: X-Real-Ip
+                value: "%DOWNSTREAM_REMOTE_ADDRESS_WITHOUT_PORT%"
+```
+
+Applying to any number of Gateways:
+```yaml
+apiVersion: gateway.envoyproxy.io/v1alpha1
+kind: ClientTrafficPolicy
+metadata:
+  name: envoy
+spec:
+  headers:
+    earlyRequestHeaders:
+      set:
+        - name: X-Real-Ip
+          value: "%DOWNSTREAM_REMOTE_ADDRESS_WITHOUT_PORT%"
+  clientIPDetection:
+    xForwardedFor:
+      trustedCIDRs:
+        - 10.96.0.0/16 # Cluster pod CIDR
+  targetSelectors: # These will apply to all Gateways
+    - group: gateway.networking.k8s.io
+      kind: Gateway
+```

docs/docs/index.mdx

@@ -35,6 +35,12 @@ Anubis is brought to you by sponsors and donors like:
 
 ### Gold Tier
 
+<a href="https://www.unipromos.com/?utm_campaign=github&utm_medium=referral&utm_content=anubis">
+  <img src="/img/sponsors/unipromos.webp" alt="Uvensys" height="64" />
+</a>
+<a href="https://uvensys.de/?utm_campaign=github&utm_medium=referral&utm_content=anubis">
+  <img src="/img/sponsors/uvensys.webp" alt="Uvensys" height="64" />
+</a>
 <a href="https://distrust.co?utm_campaign=github&utm_medium=referral&utm_content=anubis">
   <img src="/img/sponsors/distrust-logo.webp" alt="Distrust" height="64" />
 </a>

docs/docs/user/frequently-asked-questions.mdx

@@ -22,3 +22,13 @@ If you use a browser extension such as [JShelter](https://jshelter.org/), you wi
 ## Does Anubis mine Bitcoin?
 
 No. Anubis does not mine Bitcoin or any other cryptocurrency.
+
+## I disabled Just-in-time compilation in my browser. Why is Anubis slow?
+
+Anubis proof-of-work checks run an open source JavaScript program in your browser. These checks do a lot of complicated math and aim to be done quickly, so the execution speed depends on [Just-in-time (JIT) compilation](https://en.wikipedia.org/wiki/Just-in-time_compilation). JIT compiles JavaScript from the Internet into native machine code at runtime. The code produced by the JIT engine is almost as good as if it was written in a native programming language and compiled for your computer in particular. Without JIT, all JavaScript programs on every website you visit run through a slow interpreter.
+
+This interpreter is much slower than native code because it has to translate each low level JavaScript operation into many dozens of calls to execute. This means that using the interpreter incurs a massive performance hit by its very nature; it takes longer to add numbers than if the CPU just added the numbers directly.
+
+Some users choose to disable JIT as a hardening measure against theoretical browser exploits. This is a reasonable choice if you face targeted attacks from well-resourced adversaries (such as nation-state actors), but it comes with real performance costs.
+
+If you've disabled JIT and find Anubis checks slow, re-enabling JIT is the fix. There is no way for Anubis to work around this on our end.

internal/glob/glob.go

@@ -36,7 +36,7 @@ func Glob(pattern, subj string) bool {
 	end := len(parts) - 1
 
 	// Go over the leading parts and ensure they match.
-	for i := 0; i < end; i++ {
+	for i := range end {
 		idx := strings.Index(subj, parts[i])
 
 		switch i {

internal/hash_bench_test.go

@@ -184,7 +184,7 @@ func TestHashCollisions(t *testing.T) {
 	for _, prefix := range prefixes {
 		for _, suffix := range suffixes {
 			for _, variation := range variations {
-				for i := 0; i < 100; i++ {
+				for i := range 100 {
 					input := fmt.Sprintf("%s%s%s-%d", prefix, suffix, variation, i)
 					hash := XXHash64sum(input)
 					if existing, exists := xxhashHashes[hash]; exists {
@@ -211,7 +211,7 @@ func TestHashCollisions(t *testing.T) {
 
 	seqCount := 0
 	for _, pattern := range patterns {
-		for i := 0; i < 10000; i++ {
+		for i := range 10000 {
 			input := fmt.Sprintf(pattern, i)
 			hash := XXHash64sum(input)
 			if existing, exists := xxhashHashes[hash]; exists {

internal/honeypot/naive/naive.go

@@ -120,7 +120,7 @@ func (i *Impl) makeAffirmations() []string {
 	count := rand.IntN(5) + 1
 
 	var result []string
-	for j := 0; j < count; j++ {
+	for range count {
 		result = append(result, i.affirmation.Spin())
 	}
 
@@ -131,7 +131,7 @@ func (i *Impl) makeSpins() []string {
 	count := rand.IntN(5) + 1
 
 	var result []string
-	for j := 0; j < count; j++ {
+	for range count {
 		result = append(result, i.body.Spin())
 	}
 

internal/listor.go

@@ -16,7 +16,7 @@ func (lo *ListOr[T]) UnmarshalJSON(data []byte) error {
 
 	// Check if first non-whitespace character is '['
 	firstChar := data[0]
-	for i := 0; i < len(data); i++ {
+	for i := range data {
 		if data[i] != ' ' && data[i] != '\t' && data[i] != '\n' && data[i] != '\r' {
 			firstChar = data[i]
 			break
@@ -36,4 +36,4 @@ func (lo *ListOr[T]) UnmarshalJSON(data []byte) error {
 	}
 
 	return nil
-}
+}

internal/ogtags/mem_test.go

@@ -95,7 +95,7 @@ func TestMemoryUsage(t *testing.T) {
 
 	// Run getTarget many times
 	u, _ := url.Parse("/path/to/resource?query=1&foo=bar&baz=qux")
-	for i := 0; i < 10000; i++ {
+	for range 10000 {
 		_ = cache.getTarget(u)
 	}
 
@@ -129,7 +129,7 @@ func TestMemoryUsage(t *testing.T) {
 	runtime.GC()
 	runtime.ReadMemStats(&m1)
 
-	for i := 0; i < 1000; i++ {
+	for range 1000 {
 		_ = cache.extractOGTags(doc)
 	}
 

internal/ogtags/ogtags_fuzz_test.go

@@ -3,6 +3,7 @@ package ogtags
 import (
 	"context"
 	"net/url"
+	"slices"
 	"strings"
 	"testing"
 	"unicode/utf8"
@@ -78,7 +79,7 @@ func FuzzGetTarget(f *testing.F) {
 		}
 
 		// Ensure no memory corruption by calling multiple times
-		for i := 0; i < 3; i++ {
+		for range 3 {
 			result2 := cache.getTarget(u)
 			if result != result2 {
 				t.Errorf("getTarget not deterministic: %q != %q", result, result2)
@@ -148,11 +149,8 @@ func FuzzExtractOGTags(f *testing.F) {
 				}
 			}
 			if !approved {
-				for _, tag := range cache.approvedTags {
-					if property == tag {
-						approved = true
-						break
-					}
+				if slices.Contains(cache.approvedTags, property) {
+					approved = true
 				}
 			}
 			if !approved {
@@ -260,11 +258,8 @@ func FuzzExtractMetaTagInfo(f *testing.F) {
 				}
 			}
 			if !approved {
-				for _, tag := range cache.approvedTags {
-					if property == tag {
-						approved = true
-						break
-					}
+				if slices.Contains(cache.approvedTags, property) {
+					approved = true
 				}
 			}
 			if !approved {

internal/ogtags/parse.go

@@ -1,6 +1,7 @@
 package ogtags
 
 import (
+	"slices"
 	"strings"
 
 	"golang.org/x/net/html"
@@ -65,10 +66,8 @@ func (c *OGTagCache) extractMetaTagInfo(n *html.Node) (property, content string)
 	}
 
 	// Check exact matches
-	for _, tag := range c.approvedTags {
-		if propertyKey == tag {
-			return propertyKey, content
-		}
+	if slices.Contains(c.approvedTags, propertyKey) {
+		return propertyKey, content
 	}
 
 	return "", content

internal/test/playwright_test.go

@@ -270,7 +270,7 @@ func TestPlaywrightBrowser(t *testing.T) {
 
 				var performedAction action
 				var err error
-				for i := 0; i < 5; i++ {
+				for i := range 5 {
 					performedAction, err = executeTestCase(t, tc, typ, anubisURL)
 					if performedAction == tc.action {
 						break

lib/anubis.go

@@ -81,11 +81,11 @@ type Server struct {
 func (s *Server) getTokenKeyfunc() jwt.Keyfunc {
 	// return ED25519 key if HS512 is not set
 	if len(s.hs512Secret) == 0 {
-		return func(token *jwt.Token) (interface{}, error) {
+		return func(token *jwt.Token) (any, error) {
 			return s.ed25519Priv.Public().(ed25519.PublicKey), nil
 		}
 	} else {
-		return func(token *jwt.Token) (interface{}, error) {
+		return func(token *jwt.Token) (any, error) {
 			return s.hs512Secret, nil
 		}
 	}
@@ -106,6 +106,13 @@ func (s *Server) issueChallenge(ctx context.Context, r *http.Request, lg *slog.L
 		//return nil, errors.New("[unexpected] this codepath should be impossible, asked to issue a challenge for a non-challenge rule")
 	}
 
+	if rule.Challenge == nil {
+		rule.Challenge = &config.ChallengeRules{
+			Difficulty: s.policy.DefaultDifficulty,
+			Algorithm:  config.DefaultAlgorithm,
+		}
+	}
+
 	id, err := uuid.NewV7()
 	if err != nil {
 		return nil, err
@@ -491,7 +498,11 @@ func (s *Server) PassChallenge(w http.ResponseWriter, r *http.Request) {
 	chall, err := s.getChallenge(r)
 	if err != nil {
 		lg.Error("getChallenge failed", "err", err)
-		s.respondWithError(w, r, fmt.Sprintf("%s: %s", localizer.T("internal_server_error"), rule.Challenge.Algorithm), makeCode(err))
+		algorithm := "unknown"
+		if rule.Challenge != nil {
+			algorithm = rule.Challenge.Algorithm
+		}
+		s.respondWithError(w, r, fmt.Sprintf("%s: %s", localizer.T("internal_server_error"), algorithm), makeCode(err))
 		return
 	}
 
@@ -638,8 +649,16 @@ func (s *Server) check(r *http.Request, lg *slog.Logger) (policy.CheckResult, *p
 		}
 
 		if matches {
+			challRules := t.Challenge
+			if challRules == nil {
+				// Non-CHALLENGE thresholds (ALLOW/DENY) don't have challenge config.
+				// Use an empty struct so hydrateChallengeRule can fill from stored
+				// challenge data during validation, rather than baking in defaults
+				// that could mismatch the difficulty the client actually solved for.
+				challRules = &config.ChallengeRules{}
+			}
 			return cr("threshold/"+t.Name, t.Action, weight), &policy.Bot{
-				Challenge: t.Challenge,
+				Challenge: challRules,
 				Rules:     &checker.List{},
 			}, nil
 		}

lib/anubis_test.go

@@ -38,8 +38,8 @@ func NewTLogWriter(t *testing.T) io.Writer {
 
 // Write splits input on newlines and logs each line separately.
 func (w *TLogWriter) Write(p []byte) (n int, err error) {
-	lines := strings.Split(string(p), "\n")
-	for _, line := range lines {
+	lines := strings.SplitSeq(string(p), "\n")
+	for line := range lines {
 		if line != "" {
 			w.t.Log(line)
 		}

lib/challenge/error.go

@@ -10,6 +10,7 @@ var (
 	ErrFailed        = errors.New("challenge: user failed challenge")
 	ErrMissingField  = errors.New("challenge: missing field")
 	ErrInvalidFormat = errors.New("challenge: field has invalid format")
+	ErrInvalidInput  = errors.New("challenge: input is nil or missing required fields")
 )
 
 func NewError(verb, publicReason string, privateReason error) *Error {

lib/challenge/interface.go

@@ -1,6 +1,7 @@
 package challenge
 
 import (
+	"fmt"
 	"log/slog"
 	"net/http"
 	"sort"
@@ -50,12 +51,44 @@ type IssueInput struct {
 	Store     store.Interface
 }
 
+func (in *IssueInput) Valid() error {
+	if in == nil {
+		return fmt.Errorf("%w: IssueInput is nil", ErrInvalidInput)
+	}
+	if in.Rule == nil {
+		return fmt.Errorf("%w: Rule is nil", ErrInvalidInput)
+	}
+	if in.Rule.Challenge == nil {
+		return fmt.Errorf("%w: Rule.Challenge is nil", ErrInvalidInput)
+	}
+	if in.Challenge == nil {
+		return fmt.Errorf("%w: Challenge is nil", ErrInvalidInput)
+	}
+	return nil
+}
+
 type ValidateInput struct {
 	Rule      *policy.Bot
 	Challenge *Challenge
 	Store     store.Interface
 }
 
+func (in *ValidateInput) Valid() error {
+	if in == nil {
+		return fmt.Errorf("%w: ValidateInput is nil", ErrInvalidInput)
+	}
+	if in.Rule == nil {
+		return fmt.Errorf("%w: Rule is nil", ErrInvalidInput)
+	}
+	if in.Rule.Challenge == nil {
+		return fmt.Errorf("%w: Rule.Challenge is nil", ErrInvalidInput)
+	}
+	if in.Challenge == nil {
+		return fmt.Errorf("%w: Challenge is nil", ErrInvalidInput)
+	}
+	return nil
+}
+
 type Impl interface {
 	// Setup registers any additional routes with the Impl for assets or API routes.
 	Setup(mux *http.ServeMux)

lib/challenge/metarefresh/metarefresh.go

@@ -24,6 +24,10 @@ type Impl struct{}
 func (i *Impl) Setup(mux *http.ServeMux) {}
 
 func (i *Impl) Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in *challenge.IssueInput) (templ.Component, error) {
+	if err := in.Valid(); err != nil {
+		return nil, err
+	}
+
 	u, err := r.URL.Parse(anubis.BasePrefix + "/.within.website/x/cmd/anubis/api/pass-challenge")
 	if err != nil {
 		return nil, fmt.Errorf("can't render page: %w", err)
@@ -49,6 +53,10 @@ func (i *Impl) Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in
 }
 
 func (i *Impl) Validate(r *http.Request, lg *slog.Logger, in *challenge.ValidateInput) error {
+	if err := in.Valid(); err != nil {
+		return challenge.NewError("validate", "invalid input", err)
+	}
+
 	wantTime := in.Challenge.IssuedAt.Add(time.Duration(in.Rule.Challenge.Difficulty) * 800 * time.Millisecond)
 
 	if time.Now().Before(wantTime) {

lib/challenge/preact/preact.go

@@ -39,6 +39,10 @@ type impl struct{}
 func (i *impl) Setup(mux *http.ServeMux) {}
 
 func (i *impl) Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in *challenge.IssueInput) (templ.Component, error) {
+	if err := in.Valid(); err != nil {
+		return nil, err
+	}
+
 	u, err := r.URL.Parse(anubis.BasePrefix + "/.within.website/x/cmd/anubis/api/pass-challenge")
 	if err != nil {
 		return nil, fmt.Errorf("can't render page: %w", err)
@@ -57,6 +61,10 @@ func (i *impl) Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in
 }
 
 func (i *impl) Validate(r *http.Request, lg *slog.Logger, in *challenge.ValidateInput) error {
+	if err := in.Valid(); err != nil {
+		return challenge.NewError("validate", "invalid input", err)
+	}
+
 	wantTime := in.Challenge.IssuedAt.Add(time.Duration(in.Rule.Challenge.Difficulty) * 80 * time.Millisecond)
 
 	if time.Now().Before(wantTime) {

lib/challenge/proofofwork/proofofwork.go

@@ -33,6 +33,10 @@ func (i *Impl) Issue(w http.ResponseWriter, r *http.Request, lg *slog.Logger, in
 }
 
 func (i *Impl) Validate(r *http.Request, lg *slog.Logger, in *chall.ValidateInput) error {
+	if err := in.Valid(); err != nil {
+		return chall.NewError("validate", "invalid input", err)
+	}
+
 	rule := in.Rule
 	challenge := in.Challenge.RandomData
 

lib/challenge/proofofwork/proofofwork_test.go

@@ -30,6 +30,62 @@ func mkRequest(t *testing.T, values map[string]string) *http.Request {
 	return req
 }
 
+// TestValidateNilRuleChallenge reproduces the panic from
+// https://github.com/TecharoHQ/anubis/issues/1463
+//
+// When a threshold rule matches during PassChallenge, check() can return
+// a policy.Bot with Challenge == nil. After hydrateChallengeRule fails to
+// run (or the error path hits before it), Validate dereferences
+// rule.Challenge.Difficulty and panics.
+func TestValidateNilRuleChallenge(t *testing.T) {
+	i := &Impl{Algorithm: "fast"}
+	lg := slog.With()
+
+	// This is the exact response for SHA256("hunter" + "0") with 0 leading zeros required.
+	const challengeStr = "hunter"
+	const response = "2652bdba8fb4d2ab39ef28d8534d7694c557a4ae146c1e9237bd8d950280500e"
+
+	req := mkRequest(t, map[string]string{
+		"nonce":       "0",
+		"elapsedTime": "69",
+		"response":    response,
+	})
+
+	for _, tc := range []struct {
+		name  string
+		input *challenge.ValidateInput
+	}{
+		{
+			name: "nil-rule-challenge",
+			input: &challenge.ValidateInput{
+				Rule:      &policy.Bot{},
+				Challenge: &challenge.Challenge{RandomData: challengeStr},
+			},
+		},
+		{
+			name: "nil-rule",
+			input: &challenge.ValidateInput{
+				Challenge: &challenge.Challenge{RandomData: challengeStr},
+			},
+		},
+		{
+			name:  "nil-challenge",
+			input: &challenge.ValidateInput{Rule: &policy.Bot{Challenge: &config.ChallengeRules{Algorithm: "fast"}}},
+		},
+		{
+			name:  "nil-input",
+			input: nil,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			err := i.Validate(req, lg, tc.input)
+			if !errors.Is(err, challenge.ErrInvalidInput) {
+				t.Fatalf("expected ErrInvalidInput, got: %v", err)
+			}
+		})
+	}
+}
+
 func TestBasic(t *testing.T) {
 	i := &Impl{Algorithm: "fast"}
 	bot := &policy.Bot{

lib/config/config.go

@@ -228,8 +228,8 @@ type ImportStatement struct {
 }
 
 func (is *ImportStatement) open() (fs.File, error) {
-	if strings.HasPrefix(is.Import, "(data)/") {
-		fname := strings.TrimPrefix(is.Import, "(data)/")
+	if after, ok := strings.CutPrefix(is.Import, "(data)/"); ok {
+		fname := after
 		fin, err := data.BotPolicies.Open(fname)
 		return fin, err
 	}
@@ -325,7 +325,7 @@ func (sc StatusCodes) Valid() error {
 }
 
 type fileConfig struct {
-	OpenGraph   openGraphFileConfig `json:"openGraph,omitempty"`
+	OpenGraph   openGraphFileConfig `json:"openGraph"`
 	Impressum   *Impressum          `json:"impressum,omitempty"`
 	Store       *Store              `json:"store"`
 	Bots        []BotOrImport       `json:"bots"`

lib/config/config_test.go

@@ -188,7 +188,6 @@ func TestBotValid(t *testing.T) {
 	}
 
 	for _, cs := range tests {
-		cs := cs
 		t.Run(cs.name, func(t *testing.T) {
 			err := cs.bot.Valid()
 			if err == nil && cs.err == nil {
@@ -216,7 +215,6 @@ func TestConfigValidKnownGood(t *testing.T) {
 	}
 
 	for _, st := range finfos {
-		st := st
 		t.Run(st.Name(), func(t *testing.T) {
 			fin, err := os.Open(filepath.Join("testdata", "good", st.Name()))
 			if err != nil {
@@ -303,7 +301,6 @@ func TestConfigValidBad(t *testing.T) {
 	}
 
 	for _, st := range finfos {
-		st := st
 		t.Run(st.Name(), func(t *testing.T) {
 			fin, err := os.Open(filepath.Join("testdata", "bad", st.Name()))
 			if err != nil {

lib/config_test.go

@@ -24,7 +24,6 @@ func TestBadConfigs(t *testing.T) {
 	}
 
 	for _, st := range finfos {
-		st := st
 		t.Run(st.Name(), func(t *testing.T) {
 			if _, err := LoadPoliciesOrDefault(t.Context(), filepath.Join("config", "testdata", "bad", st.Name()), anubis.DefaultDifficulty, "info"); err == nil {
 				t.Fatal(err)
@@ -42,7 +41,6 @@ func TestGoodConfigs(t *testing.T) {
 	}
 
 	for _, st := range finfos {
-		st := st
 		t.Run(st.Name(), func(t *testing.T) {
 			t.Run("with-thoth", func(t *testing.T) {
 				ctx := thothmock.WithMockThoth(t)

lib/http.go

@@ -182,10 +182,7 @@ func makeCode(err error) string {
 	enc := base64.StdEncoding.EncodeToString(buf.Bytes())
 	var builder strings.Builder
 	for i := 0; i < len(enc); i += width {
-		end := i + width
-		if end > len(enc) {
-			end = len(enc)
-		}
+		end := min(i+width, len(enc))
 		builder.WriteString(enc[i:end])
 		builder.WriteByte('\n')
 	}
@@ -222,8 +219,12 @@ func (s *Server) RenderIndex(w http.ResponseWriter, r *http.Request, cr policy.C
 	chall, err := s.issueChallenge(r.Context(), r, lg, cr, rule)
 	if err != nil {
 		lg.Error("can't get challenge", "err", err)
+		algorithm := "unknown"
+		if rule.Challenge != nil {
+			algorithm = rule.Challenge.Algorithm
+		}
 		s.ClearCookie(w, CookieOpts{Name: anubis.TestCookieName, Host: r.Host})
-		s.respondWithError(w, r, fmt.Sprintf("%s: %s", localizer.T("internal_server_error"), rule.Challenge.Algorithm), makeCode(err))
+		s.respondWithError(w, r, fmt.Sprintf("%s: %s", localizer.T("internal_server_error"), algorithm), makeCode(err))
 		return
 	}
 
@@ -248,9 +249,13 @@ func (s *Server) RenderIndex(w http.ResponseWriter, r *http.Request, cr policy.C
 
 	impl, ok := challenge.Get(chall.Method)
 	if !ok {
-		lg.Error("check failed", "err", "can't get algorithm", "algorithm", rule.Challenge.Algorithm)
+		algorithm := "unknown"
+		if rule.Challenge != nil {
+			algorithm = rule.Challenge.Algorithm
+		}
+		lg.Error("check failed", "err", "can't get algorithm", "algorithm", algorithm)
 		s.ClearCookie(w, CookieOpts{Name: anubis.TestCookieName, Host: r.Host})
-		s.respondWithError(w, r, fmt.Sprintf("%s: %s", localizer.T("internal_server_error"), rule.Challenge.Algorithm), makeCode(err))
+		s.respondWithError(w, r, fmt.Sprintf("%s: %s", localizer.T("internal_server_error"), algorithm), makeCode(err))
 		return
 	}
 

lib/policy/expressions/environment_test.go

@@ -103,7 +103,7 @@ func TestBotEnvironment(t *testing.T) {
 					t.Fatalf("failed to compile expression %q: %v", tt.expression, err)
 				}
 
-				result, _, err := prog.Eval(map[string]interface{}{
+				result, _, err := prog.Eval(map[string]any{
 					"headers": tt.headers,
 				})
 				if err != nil {
@@ -168,7 +168,7 @@ func TestBotEnvironment(t *testing.T) {
 					t.Fatalf("failed to compile expression %q: %v", tt.expression, err)
 				}
 
-				result, _, err := prog.Eval(map[string]interface{}{
+				result, _, err := prog.Eval(map[string]any{
 					"path": tt.path,
 				})
 				if err != nil {
@@ -280,7 +280,7 @@ func TestBotEnvironment(t *testing.T) {
 					t.Fatalf("failed to compile expression %q: %v", tt.expression, err)
 				}
 
-				result, _, err := prog.Eval(map[string]interface{}{})
+				result, _, err := prog.Eval(map[string]any{})
 				if err != nil {
 					t.Fatalf("failed to evaluate expression %q: %v", tt.expression, err)
 				}
@@ -359,7 +359,7 @@ func TestBotEnvironment(t *testing.T) {
 						t.Fatalf("failed to compile expression %q: %v", tt.expression, err)
 					}
 
-					result, _, err := prog.Eval(map[string]interface{}{})
+					result, _, err := prog.Eval(map[string]any{})
 					if err != nil {
 						t.Fatalf("failed to evaluate expression %q: %v", tt.expression, err)
 					}
@@ -421,7 +421,7 @@ func TestBotEnvironment(t *testing.T) {
 						t.Fatalf("failed to compile expression %q: %v", tt.expression, err)
 					}
 
-					result, _, err := prog.Eval(map[string]interface{}{})
+					result, _, err := prog.Eval(map[string]any{})
 					if err != nil {
 						t.Fatalf("failed to evaluate expression %q: %v", tt.expression, err)
 					}
@@ -514,7 +514,7 @@ func TestBotEnvironment(t *testing.T) {
 						t.Fatalf("failed to compile expression %q: %v", tt.expression, err)
 					}
 
-					result, _, err := prog.Eval(map[string]interface{}{})
+					result, _, err := prog.Eval(map[string]any{})
 					if err != nil {
 						t.Fatalf("failed to evaluate expression %q: %v", tt.expression, err)
 					}
@@ -572,7 +572,7 @@ func TestBotEnvironment(t *testing.T) {
 						t.Fatalf("failed to compile expression %q: %v", tt.expression, err)
 					}
 
-					result, _, err := prog.Eval(map[string]interface{}{})
+					result, _, err := prog.Eval(map[string]any{})
 					if tt.evalError {
 						if err == nil {
 							t.Errorf("%s: expected an evaluation error, but got none", tt.description)
@@ -598,7 +598,7 @@ func TestThresholdEnvironment(t *testing.T) {
 	}
 
 	tests := []struct {
-		variables     map[string]interface{}
+		variables     map[string]any
 		name          string
 		expression    string
 		description   string
@@ -608,7 +608,7 @@ func TestThresholdEnvironment(t *testing.T) {
 		{
 			name:          "weight-variable-available",
 			expression:    `weight > 100`,
-			variables:     map[string]interface{}{"weight": 150},
+			variables:     map[string]any{"weight": 150},
 			expected:      types.Bool(true),
 			description:   "should support weight variable in expressions",
 			shouldCompile: true,
@@ -616,7 +616,7 @@ func TestThresholdEnvironment(t *testing.T) {
 		{
 			name:          "weight-variable-false-case",
 			expression:    `weight > 100`,
-			variables:     map[string]interface{}{"weight": 50},
+			variables:     map[string]any{"weight": 50},
 			expected:      types.Bool(false),
 			description:   "should correctly evaluate weight comparisons",
 			shouldCompile: true,
@@ -624,7 +624,7 @@ func TestThresholdEnvironment(t *testing.T) {
 		{
 			name:          "missingHeader-not-available",
 			expression:    `missingHeader(headers, "Test")`,
-			variables:     map[string]interface{}{},
+			variables:     map[string]any{},
 			expected:      types.Bool(false), // not used
 			description:   "should not have missingHeader function available",
 			shouldCompile: false,
@@ -667,7 +667,7 @@ func TestNewEnvironment(t *testing.T) {
 	tests := []struct {
 		name          string
 		expression    string
-		variables     map[string]interface{}
+		variables     map[string]any
 		expectBool    *bool // nil if we just want to test compilation or non-bool result
 		description   string
 		shouldCompile bool
@@ -675,7 +675,7 @@ func TestNewEnvironment(t *testing.T) {
 		{
 			name:          "randInt-function-compilation",
 			expression:    `randInt(10)`,
-			variables:     map[string]interface{}{},
+			variables:     map[string]any{},
 			expectBool:    nil, // Don't check result, just compilation
 			description:   "should compile randInt function",
 			shouldCompile: true,
@@ -683,7 +683,7 @@ func TestNewEnvironment(t *testing.T) {
 		{
 			name:          "randInt-range-validation",
 			expression:    `randInt(10) >= 0 && randInt(10) < 10`,
-			variables:     map[string]interface{}{},
+			variables:     map[string]any{},
 			expectBool:    boolPtr(true),
 			description:   "should return values in correct range",
 			shouldCompile: true,
@@ -691,7 +691,7 @@ func TestNewEnvironment(t *testing.T) {
 		{
 			name:          "strings-extension-size",
 			expression:    `"hello".size() == 5`,
-			variables:     map[string]interface{}{},
+			variables:     map[string]any{},
 			expectBool:    boolPtr(true),
 			description:   "should support string extension functions",
 			shouldCompile: true,
@@ -699,7 +699,7 @@ func TestNewEnvironment(t *testing.T) {
 		{
 			name:          "strings-extension-contains",
 			expression:    `"hello world".contains("world")`,
-			variables:     map[string]interface{}{},
+			variables:     map[string]any{},
 			expectBool:    boolPtr(true),
 			description:   "should support string contains function",
 			shouldCompile: true,
@@ -707,7 +707,7 @@ func TestNewEnvironment(t *testing.T) {
 		{
 			name:          "strings-extension-startsWith",
 			expression:    `"hello world".startsWith("hello")`,
-			variables:     map[string]interface{}{},
+			variables:     map[string]any{},
 			expectBool:    boolPtr(true),
 			description:   "should support string startsWith function",
 			shouldCompile: true,

lib/policy/policy_test.go

@@ -32,7 +32,6 @@ func TestGoodConfigs(t *testing.T) {
 	}
 
 	for _, st := range finfos {
-		st := st
 		t.Run(st.Name(), func(t *testing.T) {
 			t.Run("with-thoth", func(t *testing.T) {
 				fin, err := os.Open(filepath.Join("..", "config", "testdata", "good", st.Name()))
@@ -71,7 +70,6 @@ func TestBadConfigs(t *testing.T) {
 	}
 
 	for _, st := range finfos {
-		st := st
 		t.Run(st.Name(), func(t *testing.T) {
 			fin, err := os.Open(filepath.Join("..", "config", "testdata", "bad", st.Name()))
 			if err != nil {

lib/store/s3api/s3api_test.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"maps"
 	"sync"
 	"testing"
 	"time"
@@ -36,9 +37,7 @@ func (m *mockS3) PutObject(ctx context.Context, in *s3.PutObjectInput, _ ...func
 	m.data[aws.ToString(in.Key)] = bytes.Clone(b)
 	if in.Metadata != nil {
 		m.meta[aws.ToString(in.Key)] = map[string]string{}
-		for k, v := range in.Metadata {
-			m.meta[aws.ToString(in.Key)][k] = v
-		}
+		maps.Copy(m.meta[aws.ToString(in.Key)], in.Metadata)
 	}
 	m.bucket = aws.ToString(in.Bucket)
 	return &s3.PutObjectOutput{}, nil

lib/store/valkey/factory.go

@@ -103,7 +103,7 @@ func (s Sentinel) Valid() error {
 // redisClient is satisfied by *valkey.Client and *valkey.ClusterClient.
 type redisClient interface {
 	Get(ctx context.Context, key string) *valkey.StringCmd
-	Set(ctx context.Context, key string, value interface{}, expiration time.Duration) *valkey.StatusCmd
+	Set(ctx context.Context, key string, value any, expiration time.Duration) *valkey.StatusCmd
 	Del(ctx context.Context, keys ...string) *valkey.IntCmd
 	Ping(ctx context.Context) *valkey.StatusCmd
 }

lib/thoth/auth.go

@@ -11,8 +11,8 @@ func authUnaryClientInterceptor(token string) grpc.UnaryClientInterceptor {
 	return func(
 		ctx context.Context,
 		method string,
-		req interface{},
-		reply interface{},
+		req any,
+		reply any,
 		cc *grpc.ClientConn,
 		invoker grpc.UnaryInvoker,
 		opts ...grpc.CallOption,