Function NulByteValidationMiddleware

internal/api/server.go:25–42

NulByteValidationMiddleware rejects requests containing NUL bytes in URL path or query parameters. This prevents PostgreSQL encoding errors (SQLSTATE 22021) and returns a proper 400 Bad Request. Checks for both literal NUL bytes (\x00) and URL-encoded form (%00).

(next http.Handler)

// This prevents PostgreSQL encoding errors (SQLSTATE 22021) and returns a proper 400 Bad Request.
// Checks for both literal NUL bytes (\x00) and URL-encoded form (%00).
func NulByteValidationMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// Check URL path for literal NUL bytes or URL-encoded %00
		// Path needs %00 check because handlers call url.PathUnescape() which would decode it
		if containsNulByte(r.URL.Path) {
			writeErrorResponse(w, http.StatusBadRequest, "Invalid request: URL path contains null bytes")
			return
		}

		// Check raw query string for literal NUL bytes or URL-encoded %00
		if containsNulByte(r.URL.RawQuery) {
			writeErrorResponse(w, http.StatusBadRequest, "Invalid request: query parameters contain null bytes")
			return
		}

		next.ServeHTTP(w, r)
	})
}

// writeErrorResponse writes a JSON error response using huma's ErrorModel format
// for consistency with the rest of the API.