"Claude Code Review workflow"

Added note on HAProxy's responsibility to handle Git HTTP and bot
traffic whitelisting.

Signed-off-by: Simon Rozman <simon@rozman.si>

.github/workflows/claude-code-review.yml

@@ -0,0 +1,44 @@
+name: Claude Code Review
+
+on:
+  pull_request:
+    types: [opened, synchronize, ready_for_review, reopened]
+    # Optional: Only run on specific file changes
+    # paths:
+    #   - "src/**/*.ts"
+    #   - "src/**/*.tsx"
+    #   - "src/**/*.js"
+    #   - "src/**/*.jsx"
+
+jobs:
+  claude-review:
+    # Optional: Filter by PR author
+    # if: |
+    #   github.event.pull_request.user.login == 'external-contributor' ||
+    #   github.event.pull_request.user.login == 'new-developer' ||
+    #   github.event.pull_request.author_association == 'FIRST_TIME_CONTRIBUTOR'
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+      issues: read
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code Review
+        id: claude-review
+        uses: anthropics/claude-code-action@v1
+        with:
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+          plugin_marketplaces: 'https://github.com/anthropics/claude-code.git'
+          plugins: 'code-review@claude-code-plugins'
+          prompt: '/code-review:code-review ${{ github.repository }}/pull/${{ github.event.pull_request.number }}'
+          # See https://github.com/anthropics/claude-code-action/blob/main/docs/usage.md
+          # or https://code.claude.com/docs/en/cli-reference for available options
+

.github/workflows/claude.yml

@@ -0,0 +1,50 @@
+name: Claude Code
+
+on:
+  issue_comment:
+    types: [created]
+  pull_request_review_comment:
+    types: [created]
+  issues:
+    types: [opened, assigned]
+  pull_request_review:
+    types: [submitted]
+
+jobs:
+  claude:
+    if: |
+      (github.event_name == 'issue_comment' && contains(github.event.comment.body, '@claude')) ||
+      (github.event_name == 'pull_request_review_comment' && contains(github.event.comment.body, '@claude')) ||
+      (github.event_name == 'pull_request_review' && contains(github.event.review.body, '@claude')) ||
+      (github.event_name == 'issues' && (contains(github.event.issue.body, '@claude') || contains(github.event.issue.title, '@claude')))
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+      issues: read
+      id-token: write
+      actions: read # Required for Claude to read CI results on PRs
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 1
+
+      - name: Run Claude Code
+        id: claude
+        uses: anthropics/claude-code-action@v1
+        with:
+          claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
+
+          # This is an optional setting that allows Claude to read CI results on PRs
+          additional_permissions: |
+            actions: read
+
+          # Optional: Give a custom prompt to Claude. If this is not specified, Claude will perform the instructions specified in the comment that tagged it.
+          # prompt: 'Update the pull request description to include a summary of changes.'
+
+          # Optional: Add claude_args to customize behavior and configuration
+          # See https://github.com/anthropics/claude-code-action/blob/main/docs/usage.md
+          # or https://code.claude.com/docs/en/cli-reference for available options
+          # claude_args: '--allowed-tools Bash(gh pr:*)'
+

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
+```

lib/anubis.go

@@ -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/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/http.go

@@ -219,8 +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
 	}
 
@@ -245,9 +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
 	}