Sanitize user text input

backend/app.py

@@ -2,6 +2,8 @@ import os
 import time
 import json
 import uuid
+import math
+import re
 from datetime import datetime
 from werkzeug.security import generate_password_hash, check_password_hash
 from werkzeug.utils import secure_filename
@@ -19,10 +21,110 @@ USERS_FILE = os.path.join(DATA_DIR, "users.json")
 JOURNEYS_FILE = os.path.join(DATA_DIR, 'journeys.json')
 UPLOAD_DIR = os.path.join(BASE_DIR, "uploads")
 ALLOWED_IMAGE_EXTENSIONS = {"png", "jpg", "jpeg", "gif", "webp"}
+VALID_VISIBILITIES = {"private", "public", "shared"}
+MAX_MARKERS_PER_JOURNEY = 500
 os.makedirs(DATA_DIR, exist_ok=True)
 os.makedirs(UPLOAD_DIR, exist_ok=True)
 
 
+class ValidationError(ValueError):
+    pass
+
+
+@app.errorhandler(ValidationError)
+def handle_validation_error(error):
+    return jsonify({"error": str(error)}), 400
+
+
+def get_json_object():
+    data = request.get_json(silent=True)
+    if not isinstance(data, dict):
+        raise ValidationError("Request body must be a JSON object")
+    return data
+
+
+def clean_text(value, field, max_length, required=False, strip=True):
+    if value is None:
+        value = ""
+    if not isinstance(value, str):
+        raise ValidationError(f"{field} must be text")
+
+    # Keep newlines/tabs for Markdown, but remove non-printing control characters.
+    value = re.sub(r"[\x00-\x08\x0b\x0c\x0e-\x1f\x7f]", "", value)
+    if strip:
+        value = value.strip()
+    if required and not value:
+        raise ValidationError(f"{field} is required")
+    if len(value) > max_length:
+        raise ValidationError(f"{field} must be at most {max_length} characters")
+    return value
+
+
+def clean_number(value, field, minimum, maximum):
+    if isinstance(value, bool):
+        raise ValidationError(f"{field} must be a number")
+    try:
+        value = float(value)
+    except (TypeError, ValueError):
+        raise ValidationError(f"{field} must be a number")
+    if not math.isfinite(value) or not minimum <= value <= maximum:
+        raise ValidationError(f"{field} must be between {minimum} and {maximum}")
+    return value
+
+
+def clean_visibility(value):
+    if value not in VALID_VISIBILITIES:
+        raise ValidationError("Invalid journey visibility")
+    return value
+
+
+def clean_images(images):
+    if images is None:
+        return []
+    if not isinstance(images, list):
+        raise ValidationError("Marker images must be a list")
+    if len(images) > 20:
+        raise ValidationError("A marker can contain at most 20 images")
+
+    cleaned = []
+    for image in images:
+        if isinstance(image, str):
+            cleaned.append(clean_text(image, "Image URL", 2048, required=True))
+            continue
+        if not isinstance(image, dict):
+            raise ValidationError("Invalid marker image")
+        url = clean_text(image.get("url"), "Image URL", 2048, required=True)
+        cleaned.append({
+            "filename": clean_text(image.get("filename"), "Image filename", 255),
+            "originalName": clean_text(image.get("originalName"), "Original image name", 255),
+            "url": url,
+        })
+    return cleaned
+
+
+def clean_markers(markers):
+    if markers is None:
+        return []
+    if not isinstance(markers, list):
+        raise ValidationError("Markers must be a list")
+    if len(markers) > MAX_MARKERS_PER_JOURNEY:
+        raise ValidationError(f"A journey can contain at most {MAX_MARKERS_PER_JOURNEY} markers")
+
+    cleaned = []
+    for marker in markers:
+        if not isinstance(marker, dict):
+            raise ValidationError("Invalid marker")
+        cleaned.append({
+            "lat": clean_number(marker.get("lat"), "Marker latitude", -90, 90),
+            "lng": clean_number(marker.get("lng"), "Marker longitude", -180, 180),
+            "title": clean_text(marker.get("title"), "Marker title", 200),
+            "date": clean_text(marker.get("date"), "Marker date", 20),
+            "description": clean_text(marker.get("description"), "Marker description", 10000),
+            "images": clean_images(marker.get("images", [])),
+        })
+    return cleaned
+
+
 
 # ==================== User helpers ====================
 def require_login():
@@ -97,12 +199,11 @@ def allowed_image_file(filename):
 # ==================== Authentication endpoints ====================
 @app.route("/api/register", methods=["POST"])
 def register():
-    data = request.get_json()
+    data = get_json_object()
-    username = data.get("username")
+    username = clean_text(data.get("username"), "Username", 50, required=True)
-    password = data.get("password")
+    password = clean_text(data.get("password"), "Password", 200, required=True, strip=False)
-
+    if len(password) < 4:
-    if not username or not password:
+        raise ValidationError("Password must be at least 4 characters")
-        return jsonify({"error": "Username and password required"}), 400
 
     # Check if username already exists
     if get_user_by_username(username):
@@ -131,9 +232,9 @@ def register():
 
 @app.route("/api/login", methods=["POST"])
 def login():
-    data = request.get_json()
+    data = get_json_object()
-    username = data.get("username")
+    username = clean_text(data.get("username"), "Username", 50, required=True)
-    password = data.get("password")
+    password = clean_text(data.get("password"), "Password", 200, required=True, strip=False)
 
     user = get_user_by_username(username)
     if not user or not check_password_hash(user["password_hash"], password):
@@ -242,13 +343,9 @@ def get_journeys():
 def create_journey():
     if not require_login():
         return jsonify({'error': 'Authentication required'}), 401
-    data = request.get_json()
+    data = get_json_object()
-    if not data:
-        return jsonify({'error': 'No data provided'}), 400
 
-    title = data.get('title')
+    title = clean_text(data.get('title'), "Journey title", 200, required=True)
-    if not title:
-        return jsonify({'error': 'Journey title is required'}), 400
 
     user_id = get_current_user_id()
     journeys = load_all_journeys()
@@ -258,13 +355,13 @@ def create_journey():
         'id': new_id,
         'owner_id': user_id,
         'title': title,
-        'description': data.get('description', ''),
+        'description': clean_text(data.get('description'), "Journey description", 20000),
-        'markers': data.get('markers', []),
+        'markers': clean_markers(data.get('markers', [])),
         'created_at': datetime.now().isoformat(),
-        'visibility': data.get('visibility', 'private'),
+        'visibility': clean_visibility(data.get('visibility', 'private')),
         'shared_read': normalize_user_ids(data.get('shared_read', [])),
         'shared_edit': normalize_user_ids(data.get('shared_edit', [])),
-        'comments': data.get('comments', [])
+        'comments': []
     }
 
     journeys.append(new_journey)
@@ -295,26 +392,23 @@ def update_journey(journey_id):
     if not user_can_edit_journey(journey, user_id):
         return jsonify({'error': 'Not authorized to edit this journey'}), 403
 
-    data = request.get_json()
+    data = get_json_object()
     if 'title' in data:
-        journey['title'] = data['title']
+        journey['title'] = clean_text(data['title'], "Journey title", 200, required=True)
     if 'description' in data:
-        journey['description'] = data['description']
+        journey['description'] = clean_text(data['description'], "Journey description", 20000)
     if 'markers' in data:
-        journey['markers'] = data['markers']
+        journey['markers'] = clean_markers(data['markers'])
     sharing_fields = {'visibility', 'shared_read', 'shared_edit'}
     if sharing_fields.intersection(data.keys()):
         if journey['owner_id'] != user_id:
             return jsonify({'error': 'Only the owner can update sharing settings'}), 403
         if 'visibility' in data:
-            journey['visibility'] = data['visibility']
+            journey['visibility'] = clean_visibility(data['visibility'])
         if 'shared_read' in data:
             journey['shared_read'] = normalize_user_ids(data['shared_read'])
         if 'shared_edit' in data:
             journey['shared_edit'] = normalize_user_ids(data['shared_edit'])
-    if 'comments' in data:
-        journey['comments'] = data ['comments']
-
     save_all_journeys(journeys)
     return jsonify(journey)
 
@@ -362,10 +456,8 @@ def add_journey_comment(journey_id):
     user_id = session.get('user_id')
     if not user_id:
         return jsonify({'error': 'Authentication required'}), 401
-    data = request.get_json()
+    data = get_json_object()
-    text = data.get('text')
+    text = clean_text(data.get('text'), "Comment", 2000, required=True)
-    if not text:
-        return jsonify({'error': 'Comment text required'}), 400
 
     journey = get_journey_by_id(journey_id)
     if not journey:

journey-edit.html

@@ -335,11 +335,11 @@
             <form id="journey-form">
                 <div class="form-group">
                     <label for="journey-title">Title</label>
-                    <input type="text" id="journey-title" required>
+                    <input type="text" id="journey-title" maxlength="200" required>
                 </div>
                 <div class="form-group">
                     <label for="journey-description">Description</label>
-                    <textarea id="journey-description" rows="4"></textarea>
+                    <textarea id="journey-description" rows="4" maxlength="20000"></textarea>
                 </div>
                 <div class="form-group">
                     <label for="journey-visibility">Visibility</label>

js/auth.js

@@ -104,14 +104,28 @@ async function logout() {
 
 function escapeHtml(str) {
   if (!str) return "";
-  return str.replace(/[&<>]/g, function (m) {
+  return String(str).replace(/[&<>"']/g, function (m) {
     if (m === "&") return "&amp;";
     if (m === "<") return "&lt;";
     if (m === ">") return "&gt;";
+    if (m === '"') return "&quot;";
+    if (m === "'") return "&#39;";
     return m;
   });
 }
 
+function escapeAttribute(str) {
+  return escapeHtml(str);
+}
+
+function sanitizeDisplayUrl(url) {
+  const value = String(url || "").trim().replace(/[\u0000-\u001f\u007f\s]+/g, "");
+  if (/^(https?:\/\/|\/uploads\/|uploads\/)/i.test(value)) {
+    return value;
+  }
+  return "";
+}
+
 function showToast(msg, isError = false) {
   const toast = document.getElementById("toast");
   if (!toast) return;

js/blog-list.js

@@ -25,11 +25,13 @@ function renderJourneys(journeys) {
         return;
     }
     
-    container.innerHTML = journeys.map(journey => `
+    container.innerHTML = journeys.map(journey => {
+        const imageUrl = sanitizeDisplayUrl(journey.image || '');
+        return `
         <article class="post-card">
-            ${journey.image ? `<img class="post-card-image" src="${journey.image}" alt="${journey.title}">` : '<div class="post-card-image" style="background: var(--surface-3); display: flex; align-items: center; justify-content: center;"><i class="fas fa-image" style="font-size: 3rem; color: var(--gray-5);"></i></div>'}
+            ${imageUrl ? `<img class="post-card-image" src="${escapeAttribute(imageUrl)}" alt="${escapeAttribute(journey.title)}">` : '<div class="post-card-image" style="background: var(--surface-3); display: flex; align-items: center; justify-content: center;"><i class="fas fa-image" style="font-size: 3rem; color: var(--gray-5);"></i></div>'}
             <div class="post-card-content">
-                <h2 class="post-card-title"><a href="blog-post.html?id=${journey.id}">${escapeHtml(journey.title)}</a></h2>
+                <h2 class="post-card-title"><a href="blog-post.html?id=${encodeURIComponent(journey.id)}">${escapeHtml(journey.title)}</a></h2>
                 <div class="post-card-meta">
                     <i class="fas fa-calendar-alt"></i> ${new Date(journey.created_at).toLocaleDateString()}
                     ${journey.markers ? `<span style="margin-left: 12px;"><i class="fas fa-map-marker-alt"></i> ${journey.markers.length} chapters</span>` : ''}
@@ -38,7 +40,8 @@ function renderJourneys(journeys) {
                 <div class="post-card-excerpt">${escapeHtml(journey.description || journey.markers?.[0]?.text?.substring(0, 150) + '…')}</div>
             </div>
         </article>
-    `).join('');
+    `;
+    }).join('');
 }
 
 function getJourneyBadges(journey) {

js/blog-post.js

@@ -36,7 +36,7 @@ function renderJourney() {
             marker.images = getMarkerImages(marker);
             const images = getMarkerImagesHtml(marker.images, idx, canEdit);
             chaptersHtml += `
-                <div class="chapter" data-marker-id="${marker.id || idx}">
+                <div class="chapter" data-marker-id="${idx}">
                     <div class="chapter-header">
                         <h3>${escapeHtml(title)}</h3>
                         ${date}
@@ -60,7 +60,7 @@ function renderJourney() {
                 ${currentJourney.visibility === 'public' ? '<span class="badge">Public</span>' : ''}
                 ${currentJourney.visibility === 'shared' && !isOwner ? `<span class="badge">${canEdit ? 'Shared edit' : 'Shared'}</span>` : ''}
             </div>
-            ${currentJourney.image ? `<img class="post-image" src="${currentJourney.image}" alt="${currentJourney.title}">` : ''}
+            ${currentJourney.image ? `<img class="post-image" src="${escapeAttribute(sanitizeDisplayUrl(getUploadUrl(currentJourney.image)))}" alt="${escapeAttribute(currentJourney.title)}">` : ''}
             <div class="post-description markdown-content">${renderMarkdown(currentJourney.description)}</div>
             ${chaptersHtml}
             ${canEdit || isOwner ? `
@@ -82,7 +82,7 @@ function renderJourney() {
 
 function getUploadUrl(path) {
     if (!path) return '';
-    if (path.startsWith('http')) return path;
+    if (path.startsWith('http')) return sanitizeDisplayUrl(path);
     return API_BASE.replace('/api', path);
 }
 
@@ -115,10 +115,11 @@ function getMarkerImagesHtml(images, markerIndex, canEdit) {
     const imageHtml = images.map((image, imageIndex) => {
         const url = typeof image === 'string' ? image : image.url;
         const alt = typeof image === 'string' ? 'Journey image' : image.originalName || 'Journey image';
-        if (!url) return '';
+        const displayUrl = sanitizeDisplayUrl(getUploadUrl(url));
+        if (!displayUrl) return '';
         return `
             <div class="chapter-image-item">
-                <img src="${escapeAttribute(getUploadUrl(url))}" alt="${escapeAttribute(alt)}">
+                <img src="${escapeAttribute(displayUrl)}" alt="${escapeAttribute(alt)}">
                 ${canEdit ? `
                     <button type="button" class="remove-chapter-image" data-marker-index="${markerIndex}" data-image-index="${imageIndex}" aria-label="Remove image">
                         <i class="fas fa-times"></i>
@@ -294,7 +295,7 @@ function renderComments(comments) {
 function getCommentFormHtml() {
     return `
         <div class="comment-form">
-            <textarea id="comment-text" rows="3" placeholder="Write a comment..."></textarea>
+            <textarea id="comment-text" rows="3" maxlength="2000" placeholder="Write a comment..."></textarea>
             <button id="submit-comment" class="btn btn-sm" style="margin-top: var(--size-2);"><i class="fas fa-paper-plane"></i> Post Comment</button>
         </div>
     `;

js/journey-edit.js

@@ -21,7 +21,7 @@ function showToast(message, isError = false) {
 
 function getUploadUrl(path) {
     if (!path) return '';
-    if (path.startsWith('http')) return path;
+    if (path.startsWith('http')) return sanitizeDisplayUrl(path);
     return API_BASE.replace('/api', path);
 }
 
@@ -130,10 +130,11 @@ function renderMarkerImages(marker, idx) {
             ${images.map((image, imageIdx) => {
                 const url = typeof image === 'string' ? image : image.url;
                 const alt = typeof image === 'string' ? 'Chapter image' : image.originalName || 'Chapter image';
-                if (!url) return '';
+                const displayUrl = sanitizeDisplayUrl(getUploadUrl(url));
+                if (!displayUrl) return '';
                 return `
                     <div class="image-preview">
-                        <img src="${escapeAttribute(getUploadUrl(url))}" alt="${escapeAttribute(alt)}">
+                        <img src="${escapeAttribute(displayUrl)}" alt="${escapeAttribute(alt)}">
                         <button type="button" class="remove-image" data-index="${idx}" data-image-index="${imageIdx}" aria-label="Remove image">
                             <i class="fas fa-times"></i>
                         </button>
@@ -183,15 +184,15 @@ function renderMarkers() {
             </div>
             <div class="form-group">
                 <label>Chapter Title</label>
-                <input type="text" class="marker-title" data-index="${idx}" value="${escapeHtml(marker.title || '')}" placeholder="Title">
+                <input type="text" class="marker-title" data-index="${idx}" value="${escapeHtml(marker.title || '')}" maxlength="200" placeholder="Title">
             </div>
             <div class="form-group">
                 <label>Date (optional)</label>
-                <input type="date" class="marker-date" data-index="${idx}" value="${marker.date || ''}">
+                <input type="date" class="marker-date" data-index="${idx}" value="${escapeAttribute(marker.date || '')}">
             </div>
             <div class="form-group">
                 <label>Description</label>
-                <textarea class="marker-description" data-index="${idx}" rows="5" placeholder="Describe this chapter. You can use Markdown like **bold**, [link](https://example.com), or ![image](https://example.com/image.jpg).">${escapeHtml(marker.description || '')}</textarea>
+                <textarea class="marker-description" data-index="${idx}" rows="5" maxlength="10000" placeholder="Describe this chapter. You can use Markdown like **bold**, [link](https://example.com), or ![image](https://example.com/image.jpg).">${escapeHtml(marker.description || '')}</textarea>
                 <div class="markdown-preview markdown-content" data-preview-index="${idx}">
                     ${renderMarkdownPreview(marker.description)}
                 </div>

js/map-page.js

@@ -59,7 +59,7 @@
             }).addTo(map);
 
             marker.bindPopup(
-                `<strong>${content.title || "Untitled"}</strong>`,
+                `<strong>${escapeHtml(content.title || "Untitled")}</strong>`,
             );
             marker.on("click", () => openMarkerEditor(marker));
             marker.on("dragend", () => {
@@ -90,7 +90,7 @@
             div.dataset.lat = latlng.lat;
             div.dataset.lng = latlng.lng;
             div.innerHTML = `
-                <div class="marker-title">${content.title || "Untitled"}</div>
+                <div class="marker-title">${escapeHtml(content.title || "Untitled")}</div>
                 <div class="marker-coords">${latlng.lat.toFixed(4)}, ${latlng.lng.toFixed(4)}</div>
             `;
             div.addEventListener("click", () => {
@@ -110,7 +110,7 @@
 
         function getUploadUrl(path) {
             if (!path) return "";
-            if (path.startsWith("http")) return path;
+            if (path.startsWith("http")) return sanitizeDisplayUrl(path);
             return API_BASE.replace("/api", path);
         }
 
@@ -121,8 +121,13 @@
             images.forEach((image, index) => {
                 const item = document.createElement("div");
                 item.className = "image-preview";
+                const imagePath = typeof image === "string" ? image : image.url;
+                const imageName = typeof image === "string" ? "Marker image" : image.originalName;
+                const url = sanitizeDisplayUrl(getUploadUrl(imagePath));
+                const alt = escapeAttribute(imageName || "Marker image");
+                if (!url) return;
                 item.innerHTML = `
-                    <img src="${getUploadUrl(image.url)}" alt="${image.originalName || "Marker image"}">
+                    <img src="${escapeAttribute(url)}" alt="${alt}">
                     <button type="button" class="remove-image-btn" data-index="${index}" aria-label="Remove image">
                         <i class="fas fa-times"></i>
                     </button>
@@ -208,7 +213,7 @@
 
             // Update marker's tooltip title and popup
             activeMarker.options.title = title;
-            activeMarker.setPopupContent(`<strong>${title}</strong>`);
+            activeMarker.setPopupContent(`<strong>${escapeHtml(title)}</strong>`);
         
             // Store content for saving
             activeMarker._content = { title, date, description, images };

login.html

@@ -135,22 +135,22 @@
         <div id="login-form" class="auth-form active">
             <div class="form-group">
                 <label>Username</label>
-                <input type="text" id="login-username" required>
+                <input type="text" id="login-username" maxlength="50" required>
             </div>
             <div class="form-group">
                 <label>Password</label>
-                <input type="password" id="login-password" required>
+                <input type="password" id="login-password" maxlength="200" required>
             </div>
             <button id="login-submit" class="btn">Login</button>
         </div>
         <div id="register-form" class="auth-form">
             <div class="form-group">
                 <label>Username</label>
-                <input type="text" id="register-username" required>
+                <input type="text" id="register-username" maxlength="50" required>
             </div>
             <div class="form-group">
                 <label>Password</label>
-                <input type="password" id="register-password" required>
+                <input type="password" id="register-password" minlength="4" maxlength="200" required>
             </div>
             <button id="register-submit" class="btn">Register</button>
         </div>

map-page.html

@@ -641,6 +641,7 @@
                         <input
                             type="text"
                             id="journey-title"
+                            maxlength="200"
                             placeholder="My European Adventure"
                             required
                         />
@@ -660,6 +661,7 @@
                         >
                         <textarea
                             id="journey-description"
+                            maxlength="20000"
                             placeholder="Describe your journey..."
                         ></textarea>
                     </div>
@@ -842,6 +844,7 @@
                                 <input
                                     type="text"
                                     id="marker-title"
+                                    maxlength="200"
                                     placeholder="Eiffel Tower"
                                 />
                             </div>
@@ -853,6 +856,7 @@
                                 <label for="marker-text">Description</label>
                                 <textarea
                                     id="marker-text"
+                                    maxlength="10000"
                                     placeholder="Describe this marker. You can use Markdown like **bold**, [link](https://example.com), or ![image](https://example.com/image.jpg)."
                                 ></textarea>
                                 <div