xss漏洞修复思路

逃离我推掉我的手 2022-03-12 19:12 109阅读 0赞

public static String htmlSecurityEscape(String str) {
            if (str == null) {
                return null;
            } else {
                StringBuilder sb = null;
                int len = str.length();
    
                try {
                    for(int i = 0; i < len; ++i) {
                        char ch = str.charAt(i);
                        switch(ch) {
                        case '"':
                            if (sb == null) {
                                sb = new StringBuilder(str.length() << 1);
                                sb.append(str, 0, i);
                            }
    
                            sb.append(""");
                            break;
                        case '&':
                            int in = str.indexOf(59, i + 1);
                            if (in != -1 && in - i < 9 && str.substring(i + 1, in).indexOf(38) == -1) {
                                if (sb != null) {
                                    sb.append(ch);
                                }
                                break;
                            }
    
                            if (sb == null) {
                                sb = new StringBuilder(str.length() << 1);
                                sb.append(str, 0, i);
                            }
    
                            sb.append("&");
                            break;
                        case '\'':
                            if (sb == null) {
                                sb = new StringBuilder(str.length() << 1);
                                sb.append(str, 0, i);
                            }
    
                            sb.append("'");
                            break;
                        case '*':
                            if (i + 1 < str.length() && str.charAt(i + 1) == '/') {
                                if (sb == null) {
                                    sb = new StringBuilder(str.length() << 1);
                                    sb.append(str, 0, i);
                                }
    
                                sb.append("*/");
                                ++i;
                            } else if (sb != null) {
                                sb.append(ch);
                            }
                            break;
                        case '/':
                            if (i + 1 < str.length() && str.charAt(i + 1) == '*') {
                                if (sb == null) {
                                    sb = new StringBuilder(str.length() << 1);
                                    sb.append(str, 0, i);
                                }
    
                                sb.append("/*");
                                ++i;
                            } else if (sb != null) {
                                sb.append(ch);
                            }
                            break;
                        case '<':
                            if (sb == null) {
                                sb = new StringBuilder(str.length() << 1);
                                sb.append(str, 0, i);
                            }
    
                            sb.append("<");
                            break;
                        case '>':
                            if (sb == null) {
                                sb = new StringBuilder(str.length() << 1);
                                sb.append(str, 0, i);
                            }
    
                            sb.append(">");
                            break;
                        case '\\':
                            if (sb == null) {
                                sb = new StringBuilder(str.length() << 1);
                                sb.append(str, 0, i);
                            }
    
                            sb.append("\\");
                            break;
                        default:
                            if (Character.getDirectionality(ch) != 2 && Character.getDirectionality(ch) != 16 && Character.getDirectionality(ch) != 17) {
                                if (sb != null) {
                                    sb.append(ch);
                                }
                            } else if (sb == null) {
                                sb = new StringBuilder(str.length() << 1);
                                sb.append(str, 0, i);
                            }
                        }
                    }
                } catch (Exception var6) {
                    var6.printStackTrace();
                    System.err.println(str);
                }
    
                return null != sb ? sb.toString() : str;
            }
        }