检测一个URL是否会引起SSRF问题

SsrfChecker.java

@Slf4j
@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
public class SsrfChecker {
    private List<String> allowedProtocols;
    private List<Integer> allowedPorts;
    private List<String> deniedHosts;
    private List<String> allowedHosts;

    public boolean isSafe(String url) throws MalformedURLException {
        URL urlObj = new URL(url);
        return isSafeProtocol(urlObj) && isSafePort(urlObj) && isSafeHost(urlObj);
    }

    public boolean isSafeProtocol(URL url) {
        boolean isSafe = false;
        String protocol = url.getProtocol();
        for (String p : allowedProtocols) {
            if (protocol.equalsIgnoreCase(p)) {
                isSafe = true;
                break;
            }
        }
        return isSafe;
    }

    public boolean isSafePort(URL url) {
        boolean isSafe = false;
        int port = url.getPort();
        for (Integer p : allowedPorts) {
            if (port == p) {
                isSafe = true;
                break;
            }
        }
        return isSafe;
    }

    public boolean isSafeHost(URL url) {
        boolean isSafe = true;
        String host = url.getHost().toLowerCase();
        for (String deniedHost : deniedHosts) { // 主机黑名单
            if (isMatch(host, deniedHost)) {
                isSafe = false;
                break;
            }
        }
        for (String allowedHost : allowedHosts) { // 主机白名单
            if (isMatch(host, allowedHost)) {
                isSafe = true;
                break;
            }
        }
        return isSafe;
    }

    /**
     * 通配符匹配
     *
     * @param s 待匹配字符串
     * @param p 通配符模式串
     * @return 匹配结果
     */
    public boolean isMatch(String s, String p) {
        int m = s.length();
        int n = p.length();
        boolean[][] dp = new boolean[m + 1][n + 1];
        dp[0][0] = true;
        for (int i = 1; i <= n; i++) {
            dp[0][i] = dp[0][i - 1] && p.charAt(i - 1) == '*';
        }
        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                if (s.charAt(i - 1) == p.charAt(j - 1) || p.charAt(j - 1) == '?') {
                    dp[i][j] = dp[i - 1][j - 1];
                } else if (p.charAt(j - 1) == '*') {
                    dp[i][j] = dp[i][j - 1] || dp[i - 1][j];
                }
            }
        }
        return dp[m][n];
    }
}