Security: request size limit, symlink detection

src/Agent/AutopilotMonitor.Agent.Core/Monitoring/Collectors/DiagnosticsPathGuards.cs

@@ -106,6 +106,10 @@ namespace AutopilotMonitor.Agent.Core.Monitoring.Collectors
                     normalizedDir = Path.GetFullPath(expanded);
                 }
 
+                // Symlink / junction / reparse point detection — fail-closed
+                if (IsSymlinkOrReparsePoint(normalizedDir))
+                    return false;
+
                 // C:\Users block always applies (even in unrestricted mode)
                 if (normalizedDir.StartsWith(BlockedUsersPrefix, StringComparison.OrdinalIgnoreCase) &&
                     (normalizedDir.Length == BlockedUsersPrefix.Length ||
@@ -152,5 +156,45 @@ namespace AutopilotMonitor.Agent.Core.Monitoring.Collectors
                 return false;
             }
         }
+
+        /// <summary>
+        /// Checks whether any component of the path (directories or file) is a symlink,
+        /// junction, or other reparse point. Returns true if a reparse point is detected.
+        /// Fail-closed: returns true on any error.
+        /// </summary>
+        private static bool IsSymlinkOrReparsePoint(string path)
+        {
+            try
+            {
+                // Walk up the directory tree checking each component
+                var current = path;
+                while (!string.IsNullOrEmpty(current))
+                {
+                    var dirInfo = new DirectoryInfo(current);
+                    if (dirInfo.Exists && dirInfo.Attributes.HasFlag(FileAttributes.ReparsePoint))
+                        return true;
+
+                    var parent = Path.GetDirectoryName(current);
+                    if (parent == current) // root reached
+                        break;
+                    current = parent;
+                }
+
+                // Check the target path itself (if it's a file)
+                if (File.Exists(path))
+                {
+                    var fileInfo = new FileInfo(path);
+                    if (fileInfo.Attributes.HasFlag(FileAttributes.ReparsePoint))
+                        return true;
+                }
+
+                return false;
+            }
+            catch
+            {
+                // Fail-closed: treat errors as suspicious
+                return true;
+            }
+        }
     }
 }

src/Agent/AutopilotMonitor.Agent/buildcounter.txt

@@ -1 +1 @@
-580
+581

src/Backend/AutopilotMonitor.Functions/Functions/Feedback/FeedbackFunction.cs

@@ -135,6 +135,16 @@ namespace AutopilotMonitor.Functions.Functions.Feedback
                 var principal = req.FunctionContext.GetUser();
                 string displayName = principal?.GetDisplayName() ?? upn;
 
+                // Request body size limit (1 MB)
+                if (req.Headers.TryGetValues("Content-Length", out var clValues)
+                    && long.TryParse(clValues.FirstOrDefault(), out var contentLength)
+                    && contentLength > 1_048_576)
+                {
+                    var tooLarge = req.CreateResponse(HttpStatusCode.BadRequest);
+                    await tooLarge.WriteAsJsonAsync(new { success = false, message = "Request body too large" });
+                    return tooLarge;
+                }
+
                 var body = await req.ReadFromJsonAsync<FeedbackRequest>();
                 if (body == null)
                 {

src/Backend/AutopilotMonitor.Functions/Functions/Ingest/ReportAgentErrorFunction.cs

@@ -101,6 +101,15 @@ namespace AutopilotMonitor.Functions.Functions.Ingest
         /// </summary>
         internal async Task<HttpResponseData> ProcessReportErrorAsync(HttpRequestData req, string tenantId)
         {
+            // Request body size limit (1 MB)
+            if (req.Headers.TryGetValues("Content-Length", out var clValues)
+                && long.TryParse(clValues.FirstOrDefault(), out var contentLength)
+                && contentLength > 1_048_576)
+            {
+                _logger.LogWarning("ReportAgentError: Request body too large ({ContentLength} bytes) from tenant {TenantId}", contentLength, tenantId);
+                return req.CreateResponse(HttpStatusCode.OK); // Still 200 — agent must not retry
+            }
+
             // Parse the report body
             AgentErrorReport? report = null;
             try

src/Backend/AutopilotMonitor.Functions/Functions/Reports/SubmitSessionReportFunction.cs

@@ -49,6 +49,16 @@ namespace AutopilotMonitor.Functions.Functions.Reports
                 // Still needed: GA check for audit log skip logic
                 var isGlobalAdmin = await _globalAdminService.IsGlobalAdminAsync(userIdentifier);
 
+                // Request body size limit (1 MB)
+                if (req.Headers.TryGetValues("Content-Length", out var clValues)
+                    && long.TryParse(clValues.FirstOrDefault(), out var contentLength)
+                    && contentLength > 1_048_576)
+                {
+                    var tooLarge = req.CreateResponse(HttpStatusCode.BadRequest);
+                    await tooLarge.WriteAsJsonAsync(new { success = false, message = "Request body too large" });
+                    return tooLarge;
+                }
+
                 // Parse request body
                 var request = await req.ReadFromJsonAsync<SubmitSessionReportRequest>();
                 if (request == null)