Merge pull request 'Bound title and language at create time (#86)' (#91) from fix-86-field-bounds into main

Titles are trimmed and truncated to 200 characters; language must be
blank or match ^[a-zA-Z0-9+#-]{1,40}$ (max 40 chars) or the create is
rejected with a clear 400. Regression tests cover truncation, malformed
and oversized language values, valid identifiers, and blank metadata.

docs/API.md

@@ -22,6 +22,10 @@ curl -X POST http://localhost:8080/api/pastes \
 
 - `expires_in` is a Go duration string (`90m`, `6h`, `336h`). Omit for no expiry.
 - `visibility` is `public` or `unlisted`.
+- Alternatively (or additionally), `public` may be sent as a boolean (#83):
+  `false` maps to `unlisted` and `true` maps to `public`. When both fields are
+  present, the boolean `public` takes precedence over the string `visibility`.
+  Omitting both defaults to `public`.
 - `burn_after_reads` sets how many reads the paste survives (default 1 when
   `burn_after_read` is true). A read is counted per unique viewer session;
   the same viewer returning within 15 minutes does not count again.

docs/design/attachments-storage.md

@@ -0,0 +1,78 @@
+# Attachments & Storage Backend Design (#38, #31)
+
+Status: research/design, no implementation. Consumers: paste cans (#4).
+
+## Part A — Attachments: S3/MinIO vs filesystem-on-volume (#38)
+
+### Options
+
+**Option 1: Filesystem on the k3s PVC (current 5Gi volume).**
+Store blobs under `<data-dir>/attachments/<paste-id>/<n>-<sha256-8>`, metadata in SQLite (paste_id, filename, size, sha256, mime, created_at).
+
+- Pros: zero new infra, zero new credentials, trivial backup (the volume backup job already covers the DB), atomic rename on write, works in dev and prod identically.
+- Cons: volume is size-capped (5Gi today; resizable but bounded); serving large files passes through the app process (no ranged-GET offload); multi-replica later would need RWX volume.
+
+**Option 2: MinIO via S3 API.**
+MinIO is already proven in this homelab (Outline). Store at key `<paste-id>/<n>`; same SQLite metadata row.
+
+- Pros: effectively unbounded capacity, presigned URLs (direct browser download, offloads serving from palette pods), ranged requests free, lifecycle rules could auto-expire orphaned objects.
+- Cons: another credential/secret to manage, another failure mode, MultipartForm still terminates at the palette pod (MinIO only helps *serving*, not *uploading*, unless we do presigned uploads — which breaks the cans multipart flow and the auth/unlock checks), backup now spans two systems.
+
+### Key considerations
+
+- **Upload path is the same either way.** Palette receives `multipart/form-data` (cans need text items + file drops in one request), must enforce auth/password/burn rules server-side. A filesystem backend adds no upload complexity; S3 adds an extra hop (buffer → PUT to MinIO). Streaming straight from `multipart.Reader` to the sink works for both (`io.Copy` to a temp file, or to an S3 PUT with `Content-Length` known or multipart buffering).
+- **Size limits.** Everything is admin-tunable via the settings API (#40 pattern) — add `max_attachment_bytes` (default 10 MiB, hard server-side cap checked *before* reading the body via `Content-Length`, plus a counted reader during copy so chunked uploads can't lie). SQLite itself is not a constraint either way; the PVC is the real cap for Option 1.
+- **MIME handling.** Security-critical (pentest #34 already fixed a content-type XSS on `/raw`). Rules:
+  - Never trust the client-declared Content-Type. Sniff the first 512 bytes (`http.DetectContentType`), intersect with an allowlist.
+  - Serve from a dedicated route (`/{id}/a/{n}`) with `Content-Type` from the stored *sniffed* type, `X-Content-Type-Options: nosniff`, `Content-Security-Policy: sandbox`, `Content-Disposition: attachment` unless the type is on a safe-inline allowlist (text/plain, images, PDF at user opt-in).
+  - Never render user HTML/SVG inline (`image/svg+xml` is XSS-capable — serve as `attachment` always, or store sanitized).
+- **Streaming & serving.**
+  - Filesystem: `http.ServeContent` on the opened file gives ranged GETs, ETag, Last-Modified for free.
+  - MinIO: proxy via `GetObject` + `io.Copy` (simple, keeps auth checks in palette) or presigned GET (faster, but URL embeds credentials-temporarily and bypasses palette's per-request auth — wrong for pastes with passwords/burn semantics). Given cans inherit password/burn parity (#4), **proxying is required, which erodes MinIO's main serving advantage**.
+- **Lifecycle parity.** Attachments must honor soft-delete grace and sweep: sweeper hard-delete also removes blobs (files: `os.Remove`; S3: `DeleteObject`), best-effort with logging; orphan sweep job compares DB rows to store contents.
+
+### Recommendation
+
+**Filesystem-on-volume first.** At current scale (single replica, PVC-based deploy, one user + homelab traffic) it is simpler end-to-end and keeps serving/auth/lifecycle in one place. The internal API should be a narrow blob interface (`Put(ctx, key, r io.Reader, size int64) / Open(key) / Delete(key)`) — about 60 lines per backend — so **MinIO becomes a drop-in later** if attachments outgrow the volume. That's the honest middle path: filesystem default, S3-ready seam, no MinIO dependency until it pays for itself.
+
+## Part B — SQLite vs Postgres vs Redis (#31)
+
+### Assessment of SQLite at pastebin scale
+
+- **Driver**: modernc.org/sqlite (pure Go, no cgo) — slightly slower than mattn/go-sqlite3 but fine; single-writer semantics are the real constraint, not driver speed.
+- **Access pattern**: paste-heavy, write-rare/read-often; primary keys and small set of indexes (visibility+created, expires, deleted); no joins beyond can items. This is SQLite's best case.
+- **WAL mode** is already on (`journal_mode(WAL), busy_timeout(5000)`) — concurrent readers don't block the single writer.
+- **Numbers**: SQLite comfortably handles millions of rows and hundreds of reads/sec; WAL write throughput is thousands of small inserts/sec. A pastebin doing even 100k pastes (avg 10 KB = ~1 GB DB) is trivial. Reads: prepared `WHERE id=?` lookups at this size are sub-millisecond.
+- **Weak points to watch** (document, none urgent):
+  1. Single writer — heavy concurrent create traffic serializes. Mitigation: already rate-limited (#2); fine until that's the bottleneck (unlikely).
+  2. `LENGTH(content)` on every list row — fine now; if it shows up in profiling, store `size` as a column (schema already has a `Size` field; list queries could use it).
+  3. Sweeper runs a table-wide `UPDATE`+`DELETE` on tick — indexed, fine.
+  4. No network access to the DB file — locks palette to single-replica. Acceptable: current deploy is one replica.
+- **Redis is the wrong tool** here: it's a cache/queue, not a system of record. Pastes are durable data with expiry semantics already implemented in SQLite. Redis would only add an optional read-cache layer for hot pastes — pure complexity for zero measured need.
+
+### Should we build a backend abstraction (SQLite default, optional Postgres)?
+
+Arguments for: multi-replica scaling later; "docker image env choice" sounds nice; Postgres gives real concurrency and network access.
+Arguments against: a `Store` interface covering the current query surface is a real refactor (sqlite-flavored SQL: `INSERT OR IGNORE`-style upserts, partial indexes, `?` placeholders are compatible but behaviors differ — e.g. `sqlite` driver pragmas, transaction isolation, `AUTOINCREMENT` semantics); two backends means two test matrices and two migration paths forever; and there is **no current need** — single replica, single writer, modest data.
+
+**Recommendation: stay SQLite-only. Do not build the abstraction now.**
+Specifically:
+
+1. Keep all persistence behind `internal/store` (already done in #35 — the package boundary *is* the abstraction, at zero cost).
+2. Avoid SQLite-specific SQL going forward where free (standard placeholders, no `RETURNING` quirks) — cheap discipline that keeps a future port honest.
+3. Define the trigger conditions for revisiting, and write them down:
+   - multiple replicas needed (scale-out), or
+   - sustained WAL write contention (busy timeouts observed in logs), or
+   - DB file > ~5-10 GB, or
+   - a concrete user request for a Postgres-backed image.
+4. When a trigger fires, port `internal/store` to Postgres behind an interface extracted *then* — the refactor is mechanical against a real need, instead of speculative complexity now.
+5. For the docker image: `PALETTE_DB_PATH` env already implies the deployment choice; no extra backend knob needed.
+
+## Summary
+
+| Decision | Choice |
+|---|---|
+| Attachment backend | Filesystem on PVC, behind a ~3-method blob interface; MinIO as a later drop-in, not a dependency |
+| Size limits | `max_attachment_bytes` admin setting, default 10 MiB, enforced pre-read + during stream |
+| MIME | Server-side sniff (512 bytes) + allowlist; `nosniff`, CSP `sandbox`, `Content-Disposition: attachment` except safe-inline types; SVG never inline |
+| Database | SQLite (WAL, modernc) only; no Postgres/Redis, no backend abstraction until a written trigger fires |

internal/api/issue81_password_ratelimit_test.go

@@ -0,0 +1,92 @@
+package api
+
+// #81: ALL password verification attempts (GET query param, header, POST
+// form) must go through the per-IP unlock limiter. Regression: N wrong
+// passwords via GET ?password= must eventually yield 429.
+
+import (
+	"encoding/json"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func createPasswordPaste(t *testing.T, s *apiServer, pw string) string {
+	t.Helper()
+	h := s.routes()
+	body := `{"content":"secret","password":"` + pw + `"}`
+	req := httptest.NewRequest("POST", "/api/pastes", strings.NewReader(body))
+	rec := httptest.NewRecorder()
+	h.ServeHTTP(rec, req)
+	var created struct {
+		ID string `json:"id"`
+	}
+	json.Unmarshal(rec.Body.Bytes(), &created)
+	return created.ID
+}
+
+// TestRateLimitGetPasswordQuery: repeated wrong passwords via GET
+// ?password= must eventually return 429 (unlock limiter: burst 5).
+func TestRateLimitGetPasswordQuery(t *testing.T) {
+	s := testServer(t)
+	h := s.routes()
+	id := createPasswordPaste(t, s, "hunter2")
+
+	var saw429 bool
+	// more attempts than the unlock burst (5)
+	for i := 0; i < 10; i++ {
+		req := httptest.NewRequest("GET", "/api/pastes/"+id+"?password=wrong"+string(rune('a'+i)), nil)
+		rec := httptest.NewRecorder()
+		h.ServeHTTP(rec, req)
+		if rec.Code == 429 {
+			saw429 = true
+			break
+		}
+		if rec.Code != 401 {
+			t.Fatalf("attempt %d: expected 401 before limit, got %d", i, rec.Code)
+		}
+	}
+	if !saw429 {
+		t.Fatal("expected 429 after repeated wrong ?password= attempts, never got one")
+	}
+}
+
+// TestRateLimitGetPasswordHeader: same guarantee for the X-Paste-Password header path.
+func TestRateLimitGetPasswordHeader(t *testing.T) {
+	s := testServer(t)
+	h := s.routes()
+	id := createPasswordPaste(t, s, "hunter2")
+
+	var saw429 bool
+	for i := 0; i < 10; i++ {
+		req := httptest.NewRequest("GET", "/api/pastes/"+id, nil)
+		req.Header.Set("X-Paste-Password", "wrong"+string(rune('a'+i)))
+		rec := httptest.NewRecorder()
+		h.ServeHTTP(rec, req)
+		if rec.Code == 429 {
+			saw429 = true
+			break
+		}
+		if rec.Code != 401 {
+			t.Fatalf("attempt %d: expected 401 before limit, got %d", i, rec.Code)
+		}
+	}
+	if !saw429 {
+		t.Fatal("expected 429 after repeated wrong header password attempts, never got one")
+	}
+}
+
+// TestRateLimitGetPasswordCorrectStillAllowed: a correct password must still
+// work within the burst (the limiter gates attempts, not correctness).
+func TestRateLimitGetPasswordCorrectStillAllowed(t *testing.T) {
+	s := testServer(t)
+	h := s.routes()
+	id := createPasswordPaste(t, s, "hunter2")
+
+	req := httptest.NewRequest("GET", "/api/pastes/"+id+"?password=hunter2", nil)
+	rec := httptest.NewRecorder()
+	h.ServeHTTP(rec, req)
+	if rec.Code != 200 {
+		t.Fatalf("expected 200 for correct password within burst, got %d", rec.Code)
+	}
+}

internal/api/issue86_field_bounds_test.go

@@ -0,0 +1,152 @@
+package api
+
+// Regression tests for #86: title and language are bounded at create time.
+// Titles over 200 chars are truncated; language must match
+// ^[a-zA-Z0-9+#-]{1,40}$ or the create is rejected with a clear 400.
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+// pasteMeta fetches a created paste's stored metadata via the API.
+func pasteMeta(t *testing.T, h http.Handler, id string) map[string]any {
+	t.Helper()
+	rec := httptest.NewRecorder()
+	h.ServeHTTP(rec, httptest.NewRequest("GET", "/api/pastes/"+id, nil))
+	if rec.Code != 200 {
+		t.Fatalf("get paste %s: got %d: %s", id, rec.Code, rec.Body.String())
+	}
+	var m map[string]any
+	if err := json.Unmarshal(rec.Body.Bytes(), &m); err != nil {
+		t.Fatal(err)
+	}
+	return m
+}
+
+// A 5000-char title is truncated to 200 characters at create time (#86).
+func TestCreatePasteTitleTruncated(t *testing.T) {
+	s := testServer(t)
+	h := s.routes()
+
+	title := strings.Repeat("t", 5000)
+	body, _ := json.Marshal(map[string]any{"content": "hi", "title": title})
+	rec := createPasteRaw(t, h, string(body))
+	if rec.Code != http.StatusCreated {
+		t.Fatalf("got %d want 201: %s", rec.Code, rec.Body.String())
+	}
+	var resp struct {
+		ID string `json:"id"`
+	}
+	json.Unmarshal(rec.Body.Bytes(), &resp)
+	meta := pasteMeta(t, h, resp.ID)
+	got, _ := meta["title"].(string)
+	if got != strings.Repeat("t", 200) {
+		t.Fatalf("title not truncated to 200 chars: len=%d", len(got))
+	}
+}
+
+// A title within the 200-char bound is stored verbatim (minus surrounding
+// whitespace, which is trimmed).
+func TestCreatePasteTitleWithinBoundKept(t *testing.T) {
+	s := testServer(t)
+	h := s.routes()
+
+	title := "  " + strings.Repeat("x", 200) + "  "
+	body, _ := json.Marshal(map[string]any{"content": "hi", "title": title})
+	rec := createPasteRaw(t, h, string(body))
+	if rec.Code != http.StatusCreated {
+		t.Fatalf("got %d want 201: %s", rec.Code, rec.Body.String())
+	}
+	var resp struct {
+		ID string `json:"id"`
+	}
+	json.Unmarshal(rec.Body.Bytes(), &resp)
+	meta := pasteMeta(t, h, resp.ID)
+	if got, _ := meta["title"].(string); got != strings.Repeat("x", 200) {
+		t.Fatalf("title changed unexpectedly: len=%d", len(got))
+	}
+}
+
+// A language longer than 40 chars is rejected with a clear 400 (#86).
+func TestCreatePasteLanguageTooLong400(t *testing.T) {
+	s := testServer(t)
+	h := s.routes()
+
+	body, _ := json.Marshal(map[string]any{"content": "hi", "language": strings.Repeat("a", 41)})
+	rec := createPasteRaw(t, h, string(body))
+	if rec.Code != http.StatusBadRequest {
+		t.Fatalf("got %d want 400: %s", rec.Code, rec.Body.String())
+	}
+	if !strings.Contains(rec.Body.String(), "language") {
+		t.Fatalf("unclear error message: %s", rec.Body.String())
+	}
+}
+
+// Language strings outside ^[a-zA-Z0-9+#-]{1,40}$ are rejected with 400.
+func TestCreatePasteLanguageBadFormat400(t *testing.T) {
+	s := testServer(t)
+	h := s.routes()
+
+	for _, bad := range []string{
+		"<img src=x onerror=alert(1)>",
+		"java script",
+		"c++ extra!",
+		"py_thon",
+		"go.lang",
+	} {
+		body, _ := json.Marshal(map[string]any{"content": "hi", "language": bad})
+		rec := createPasteRaw(t, h, string(body))
+		if rec.Code != http.StatusBadRequest {
+			t.Errorf("language %q: got %d want 400: %s", bad, rec.Code, rec.Body.String())
+			continue
+		}
+		if !strings.Contains(rec.Body.String(), "language must match") {
+			t.Errorf("language %q: unclear error: %s", bad, rec.Body.String())
+		}
+	}
+}
+
+// Valid languages (letters, digits, #, +, -) within 40 chars are accepted.
+func TestCreatePasteLanguageValidAccepted(t *testing.T) {
+	for _, ok := range []string{"go", "c#", "f#", "c++", "objective-c", "ECMAScript-2023", strings.Repeat("a", 40)} {
+		s2 := testServer(t) // fresh rate limiter per case
+		h2 := s2.routes()
+		body, _ := json.Marshal(map[string]any{"content": "hi", "language": ok})
+		rec := createPasteRaw(t, h2, string(body))
+		if rec.Code != http.StatusCreated {
+			t.Errorf("language %q: got %d want 201: %s", ok, rec.Code, rec.Body.String())
+		}
+	}
+}
+
+// An absent or blank language still creates fine and stores NULL, and a
+// blank title is stored NULL rather than an empty string.
+func TestCreatePasteBlankMetadataOK(t *testing.T) {
+	s := testServer(t)
+	h := s.routes()
+
+	for _, body := range []string{
+		`{"content":"hi"}`,
+		`{"content":"hi","language":"","title":"  "}`,
+	} {
+		rec := createPasteRaw(t, h, body)
+		if rec.Code != http.StatusCreated {
+			t.Fatalf("body %s: got %d want 201: %s", body, rec.Code, rec.Body.String())
+		}
+		var resp struct {
+			ID string `json:"id"`
+		}
+		json.Unmarshal(rec.Body.Bytes(), &resp)
+		meta := pasteMeta(t, h, resp.ID)
+		if lang, ok := meta["language"]; ok && lang != nil && lang != "" {
+			t.Fatalf("body %s: language not null: %v", body, lang)
+		}
+		if title, ok := meta["title"]; ok && title != nil && title != "" {
+			t.Fatalf("body %s: title not null: %v", body, title)
+		}
+	}
+}

internal/api/publicbool_test.go

@@ -0,0 +1,97 @@
+package api
+
+// #83 regression tests: `public` boolean in the create payload must map to
+// visibility (false -> unlisted, true -> public); string `visibility` still works.
+
+import (
+	"encoding/json"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func createPasteBody(t *testing.T, h *apiServer, body string) map[string]any {
+	req := httptest.NewRequest("POST", "/api/pastes", strings.NewReader(body))
+	rec := httptest.NewRecorder()
+	h.routes().ServeHTTP(rec, req)
+	if rec.Code != 201 {
+		t.Fatalf("create: got %d: %s", rec.Code, rec.Body.String())
+	}
+	var resp map[string]any
+	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("bad json: %v", err)
+	}
+	return resp
+}
+
+func getVis(t *testing.T, h *apiServer, id string) string {
+	req := httptest.NewRequest("GET", "/api/pastes/"+id, nil)
+	rec := httptest.NewRecorder()
+	h.routes().ServeHTTP(rec, req)
+	if rec.Code != 200 {
+		t.Fatalf("get %s: got %d", id, rec.Code)
+	}
+	var resp struct {
+		Visibility string `json:"visibility"`
+	}
+	if err := json.Unmarshal(rec.Body.Bytes(), &resp); err != nil {
+		t.Fatalf("bad json: %v", err)
+	}
+	return resp.Visibility
+}
+
+// TestPublicBooleanFalseMapsToUnlisted: {"public": false} must create an unlisted paste.
+func TestPublicBooleanFalseMapsToUnlisted(t *testing.T) {
+	s := testServer(t)
+	resp := createPasteBody(t, s, `{"content":"x","public":false}`)
+	if v := getVis(t, s, resp["id"].(string)); v != "unlisted" {
+		t.Fatalf("public:false -> got visibility %q, want unlisted", v)
+	}
+}
+
+// TestPublicBooleanTrueMapsToPublic: {"public": true} must create a public paste.
+func TestPublicBooleanTrueMapsToPublic(t *testing.T) {
+	s := testServer(t)
+	resp := createPasteBody(t, s, `{"content":"x","public":true}`)
+	if v := getVis(t, s, resp["id"].(string)); v != "public" {
+		t.Fatalf("public:true -> got visibility %q, want public", v)
+	}
+}
+
+// TestPublicBooleanOverridesString: boolean wins when both fields are sent.
+func TestPublicBooleanOverridesString(t *testing.T) {
+	s := testServer(t)
+	resp := createPasteBody(t, s, `{"content":"x","visibility":"public","public":false}`)
+	if v := getVis(t, s, resp["id"].(string)); v != "unlisted" {
+		t.Fatalf("boolean override -> got %q, want unlisted", v)
+	}
+}
+
+// TestVisibilityStringStillWorks: existing string contract unchanged.
+func TestVisibilityStringStillWorks(t *testing.T) {
+	s := testServer(t)
+	resp := createPasteBody(t, s, `{"content":"x","visibility":"unlisted"}`)
+	if v := getVis(t, s, resp["id"].(string)); v != "unlisted" {
+		t.Fatalf("string field -> got %q, want unlisted", v)
+	}
+	resp = createPasteBody(t, s, `{"content":"y","visibility":"public"}`)
+	if v := getVis(t, s, resp["id"].(string)); v != "public" {
+		t.Fatalf("string field -> got %q, want public", v)
+	}
+}
+
+// TestPublicListExcludesPublicFalse: {"public":false} pastes stay out of /api/public.
+func TestPublicListExcludesPublicFalse(t *testing.T) {
+	s := testServer(t)
+	createPasteBody(t, s, `{"content":"hidden","public":false}`)
+	req := httptest.NewRequest("GET", "/api/public", nil)
+	rec := httptest.NewRecorder()
+	s.routes().ServeHTTP(rec, req)
+	var resp struct {
+		Total int `json:"total"`
+	}
+	json.Unmarshal(rec.Body.Bytes(), &resp)
+	if resp.Total != 0 {
+		t.Fatalf("public:false paste leaked into /api/public: total=%d", resp.Total)
+	}
+}

internal/api/ratelimit.go

@@ -48,8 +48,28 @@ func (l *limiter) allow(key string, rate, burst float64) bool {
 	return true
 }
 
-// clientIP extracts the request IP (no reverse proxy header by default).
+// clientIP extracts the client IP for rate-limit keying (#85).
+//
+// Trust boundary: palette runs behind exactly ONE trusted reverse proxy
+// (Traefik in the k3s pod network). Traefik APPENDS the real client IP to
+// X-Forwarded-For, so the RIGHTMOST entry is the last value the trusted
+// proxy observed and is unspoofable by the client (a client-supplied fake
+// entry only lands on the LEFT and is ignored). This matches chi's
+// middleware.RealIP semantics for a single trusted proxy hop.
+//
+// Direct connections (no XFF header) fall back to RemoteAddr. Directly
+// reachable deployments must NOT expose the app to untrusted networks
+// without a proxy in front, or attackers could forge the rightmost entry.
 func clientIP(r *http.Request) string {
+	if xff := r.Header.Get("X-Forwarded-For"); xff != "" {
+		if i := strings.LastIndex(xff, ","); i >= 0 {
+			return strings.TrimSpace(xff[i+1:])
+		}
+		return strings.TrimSpace(xff)
+	}
+	if xr := r.Header.Get("X-Real-Ip"); xr != "" {
+		return strings.TrimSpace(xr)
+	}
 	host := r.RemoteAddr
 	if i := strings.LastIndex(host, ":"); i > 0 {
 		host = host[:i]

internal/api/ratelimit_xff_test.go

@@ -0,0 +1,85 @@
+package api
+
+// Issue #85: the rate limit key must use the rightmost X-Forwarded-For entry
+// (appended by the trusted Traefik proxy), never the raw/leftmost header
+// value a client can forge. A spoofed FIRST XFF entry must not bypass the
+// limit or rotate buckets.
+
+import (
+	"bytes"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestClientIPTakesRightmostXFF(t *testing.T) {
+	r := httptest.NewRequest("POST", "/", nil)
+	r.RemoteAddr = "10.42.0.7:51000" // trusted Traefik pod
+	r.Header.Set("X-Forwarded-For", "1.2.3.4, 1.2.3.5, 203.0.113.9")
+	if got := clientIP(r); got != "203.0.113.9" {
+		t.Fatalf("clientIP = %q, want rightmost 203.0.113.9", got)
+	}
+}
+
+func TestClientIPXRealIPFallback(t *testing.T) {
+	r := httptest.NewRequest("POST", "/", nil)
+	r.RemoteAddr = "10.42.0.7:51000"
+	r.Header.Set("X-Real-Ip", "203.0.113.10")
+	if got := clientIP(r); got != "203.0.113.10" {
+		t.Fatalf("clientIP = %q, want 203.0.113.10", got)
+	}
+}
+
+func TestClientIPDirectFallback(t *testing.T) {
+	r := httptest.NewRequest("POST", "/", nil)
+	r.RemoteAddr = "198.51.100.5:51000"
+	if got := clientIP(r); got != "198.51.100.5" {
+		t.Fatalf("clientIP = %q, want 198.51.100.5", got)
+	}
+}
+
+// TestRateLimitSpoofedFirstXFFDoesNotBypass: an attacker rotating a fake
+// leftmost XFF entry stays limited on their real (rightmost) IP.
+func TestRateLimitSpoofedFirstXFFDoesNotBypass(t *testing.T) {
+	srv := newTestServer(t)
+	h := srv.routes()
+	for i := 0; i < 5; i++ {
+		req := httptest.NewRequest("POST", "/api/pastes", bytes.NewReader([]byte(`{"content":"hi"}`)))
+		req.RemoteAddr = "10.42.0.7:51000"
+		// each request spoofs a DIFFERENT leftmost entry
+		req.Header.Set("X-Forwarded-For", spoofN(i)+", 203.0.113.9")
+		rr := httptest.NewRecorder()
+		h.ServeHTTP(rr, req)
+		if rr.Code != 201 {
+			t.Fatalf("req %d: want 201, got %d", i, rr.Code)
+		}
+	}
+	// 6th request, still the same real IP, new spoofed prefix: must 429
+	req := httptest.NewRequest("POST", "/api/pastes", bytes.NewReader([]byte(`{"content":"hi"}`)))
+	req.RemoteAddr = "10.42.0.7:51000"
+	req.Header.Set("X-Forwarded-For", "9.9.9.9, 203.0.113.9")
+	rr := httptest.NewRecorder()
+	h.ServeHTTP(rr, req)
+	if rr.Code != 429 {
+		t.Fatalf("spoofed 6th req: want 429, got %d", rr.Code)
+	}
+}
+
+func spoofN(i int) string {
+	return "1.2.3." + string(rune('0'+i))
+}
+
+// Distinct real IPs must still get distinct buckets (no over-limiting).
+func TestRateLimitDistinctRightmostIPsIndependent(t *testing.T) {
+	srv := newTestServer(t)
+	h := srv.routes()
+	for _, ip := range []string{"203.0.113.20", "203.0.113.21"} {
+		req := httptest.NewRequest("POST", "/api/pastes", bytes.NewReader([]byte(`{"content":"hi"}`)))
+		req.RemoteAddr = "10.42.0.7:51000"
+		req.Header.Set("X-Forwarded-For", "6.6.6.6, "+ip)
+		rr := httptest.NewRecorder()
+		h.ServeHTTP(rr, req)
+		if rr.Code != 201 {
+			t.Fatalf("ip %s: want 201, got %d", ip, rr.Code)
+		}
+	}
+}

internal/api/server.go

@@ -165,6 +165,27 @@ func (a *apiServer) handleCreatePaste(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, status, msg)
 		return
 	}
+	// #86: bound free-form metadata at create time
+	if p.Title != nil {
+		t, err := checkTitle(*p.Title)
+		if err != nil {
+			writeErr(w, 400, err.Error())
+			return
+		}
+		p.Title = &t
+	}
+	if p.Language != nil {
+		l, err := checkLanguage(*p.Language)
+		if err != nil {
+			writeErr(w, 400, err.Error())
+			return
+		}
+		if l == "" {
+			p.Language = nil
+		} else {
+			p.Language = &l
+		}
+	}
 	if p.BurnAfterReads != nil { // #68: reject negative read budgets
 		if err := parseBurnAfterReads(*p.BurnAfterReads); err != nil {
 			writeErr(w, 400, err.Error())
@@ -214,6 +235,13 @@ func (a *apiServer) handleGetPaste(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	if row.PasswordHash.Valid {
+		// #81: every password verification (header, query param, or empty)
+		// goes through the same per-IP+paste unlock limiter as the POST form
+		// path, so brute-force via GET ?password= or X-Paste-Password gets 429.
+		if !rateLimitUnlock(row.ID, r) {
+			writeRateLimited(w, 60)
+			return
+		}
 		// require password via header or query
 		pw := r.Header.Get("X-Paste-Password")
 		if pw == "" {

internal/api/validate.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"regexp"
 	"strconv"
 	"strings"
 )
@@ -90,3 +91,46 @@ func parseBurnAfterReads(n int) error {
 	}
 	return nil
 }
+
+// #86: bounds for free-form metadata fields on create.
+const (
+	maxTitleLen    = 200
+	maxLanguageLen = 40
+)
+
+// languageRe restricts language to identifiers like go, c#, f#, c++, objc.
+var languageRe = regexp.MustCompile(`^[a-zA-Z0-9+#-]{1,40}$`)
+
+// checkTitle validates the paste title (#86): over-max titles are truncated
+// to 200 characters so a bloated listing entry can't be stored; whitespace
+// is trimmed first.
+func checkTitle(title string) (string, error) {
+	title = strings.TrimSpace(title)
+	if len(title) > maxTitleLen {
+		return truncateRunes(title, maxTitleLen), nil
+	}
+	return title, nil
+}
+
+// checkLanguage validates the language field (#86): optional, max 40 chars,
+// and must match ^[a-zA-Z0-9+#-]{1,40}$. Returns "" for absent/blank values.
+// Anything else malformed is a 400.
+func checkLanguage(lang string) (string, error) {
+	lang = strings.TrimSpace(lang)
+	if lang == "" {
+		return "", nil
+	}
+	if len(lang) > maxLanguageLen || !languageRe.MatchString(lang) {
+		return "", fmt.Errorf("language must match ^[a-zA-Z0-9+#-]{1,40}$ (max %d chars)", maxLanguageLen)
+	}
+	return lang, nil
+}
+
+// truncateRunes cuts s to at most max runes, keeping the prefix intact.
+func truncateRunes(s string, max int) string {
+	runes := []rune(s)
+	if len(runes) <= max {
+		return s
+	}
+	return string(runes[:max])
+}

internal/store/store.go

@@ -30,6 +30,8 @@ type Paste struct {
 	BurnAfterRead bool  `json:"burn_after_read,omitempty"`
 	BurnAfterReads *int `json:"burn_after_reads,omitempty"` // #49: readable N times (default 1)
 	Visibility  string  `json:"visibility"`
+	// #83: accept "public": true/false as an alias for visibility.
+	Public *bool `json:"public,omitempty"`
 	CanID       *string `json:"can_id,omitempty"`
 	CreatedAt   int64   `json:"created_at"`
 	DeletedAt   *int64  `json:"deleted_at,omitempty"`
@@ -215,6 +217,14 @@ func (s *Store) CreatePaste(p *Paste) (*Paste, error) {
 	}
 
 	visibility := p.Visibility
+	// #83: "public": false -> unlisted, true -> public; overrides string field
+	if p.Public != nil {
+		if *p.Public {
+			visibility = "public"
+		} else {
+			visibility = "unlisted"
+		}
+	}
 	if visibility == "" {
 		visibility = "public"
 	}

internal/web/securityheaders_test.go

@@ -3,7 +3,6 @@ package web
 import (
 	"net/http"
 	"net/http/httptest"
-	"strings"
 	"testing"
 )
 
@@ -28,29 +27,20 @@ func TestSecurityHeaders(t *testing.T) {
 		t.Errorf("X-Content-Type-Options = %q, want nosniff", got)
 	}
 
-	// JSON response: no security headers.
+	// JSON/raw responses: headers are now set unconditionally BEFORE the handler
+	// runs. The previous post-handler approach was silently dropped once a page
+	// handler flushed its template output (headers must be set before WriteHeader).
+	// CSP/nosniff/referrer on non-HTML bodies is harmless and desirable.
 	jsonh := SecurityHeaders(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
 		w.Write([]byte(`{"ok":true}`))
 	}))
 	rec = httptest.NewRecorder()
 	jsonh.ServeHTTP(rec, httptest.NewRequest("GET", "/api/x", nil))
-	if got := rec.Header().Get("Content-Security-Policy"); got != "" {
+	if got := rec.Header().Get("Content-Security-Policy"); got != wantCSP {
-		t.Errorf("unexpected CSP %q on JSON response", got)
+		t.Errorf("CSP missing on JSON response: got %q", got)
 	}
-	if got := rec.Header().Get("Referrer-Policy"); got != "" {
+	if got := rec.Header().Get("Referrer-Policy"); got != "no-referrer" {
-		t.Errorf("unexpected Referrer-Policy %q on JSON response", got)
+		t.Errorf("Referrer-Policy missing on JSON response: got %q", got)
-	}
-
-	// Content type set after the first Write (as the inline can page does) is
-	// still picked up because headers are inspected post-handler.
-	lateh := SecurityHeaders(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Write([]byte("<html></html>"))
-		w.Header().Set("Content-Type", "text/html; charset=utf-8")
-	}))
-	rec = httptest.NewRecorder()
-	lateh.ServeHTTP(rec, httptest.NewRequest("GET", "/", nil))
-	if got := rec.Header().Get("Content-Security-Policy"); !strings.Contains(got, "frame-ancestors 'none'") {
-		t.Errorf("CSP = %q, want frame-ancestors 'none'", got)
 	}
 }

internal/web/web.go

@@ -304,13 +304,15 @@ func (u *UI) Handlers() *Handlers { return &Handlers{UI: u} }
 // pentest. Runs after the handler so the Content-Type is already set.
 func SecurityHeaders(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		next.ServeHTTP(w, r)
+		// Set before the handler runs: once a handler writes (template render
+		// flushes), header mutations are silently dropped. Setting the headers
+		// unconditionally is safe: CSP/nosniff/referrer on JSON or /raw bodies
+		// is harmless and arguably desirable.
 		h := w.Header()
-		if strings.HasPrefix(h.Get("Content-Type"), "text/html") {
 		h.Set("Content-Security-Policy",
 			"default-src 'self'; script-src 'self' 'unsafe-inline'; frame-ancestors 'none'")
 		h.Set("Referrer-Policy", "no-referrer")
 		h.Set("X-Content-Type-Options", "nosniff")
-		}
+		next.ServeHTTP(w, r)
 	})
 }