Secure Code Warrior_.Net Core 資安練習_SQL Injection防範(二)

 

一個有漏洞的程式碼範例


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using CoreChallenge.Models;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Reflection;
using System.Security.Cryptography;
namespace CoreChallenge.Db
{
    public class DbOperations : IDbOperations
    {
        const string DbName = "CoreChallenge";

        string ConnectionString { get; }
        string DbFileName { get; }

        SqlConnection Connection { get; set; }

        public DbOperations(string connectionString)
        {
            DbFileName = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), $"{DbName}.mdf");
            ConnectionString = string.Format(connectionString, DbName);

            if (File.Exists(DbFileName))
                OpenConnection();
            else
                CreateDb(string.Format(connectionString, "master"));
        }

        void OpenConnection()
        {
            Connection = new SqlConnection(ConnectionString);

            Connection.Open();
        }

        public void CreateDb(string connectionString)
        {
            if (File.Exists(DbFileName))
                File.Delete(DbFileName);

            using (var connection = new SqlConnection(connectionString))
            {
                connection.Open();

                DetachDatabase(connection);

                using (SqlCommand sqlCommand = connection.CreateCommand())
                {
                    sqlCommand.CommandText = $"CREATE DATABASE {DbName} ON (NAME = N'{DbName}', FILENAME = '{DbFileName}')";

                    sqlCommand.ExecuteNonQuery();
                }

                connection.Close();
            }

            Seed();
        }

        static void DetachDatabase(SqlConnection sqlConnection)
        {
            using (var cmd = sqlConnection.CreateCommand())
            {
                cmd.CommandText = String.Format("exec sp_detach_db '{0}'", DbName);

                cmd.ExecuteNonQuery();
            }
        }

        void Seed()
        {
            OpenConnection();
            CreateTables();
            FillData();
        }

        void FillData()
        {
            AddOrder(new Order { UserName = "John Smith", UserPhone = "Test 1", UserAddress = "Test 2", OrderDate = DateTime.Now.AddDays(-1) });
            AddOrder(new Order { UserName = "Juan Carlos", UserPhone = "Test 4", UserAddress = "Test 5", OrderDate = DateTime.Now.AddDays(-2) });
            AddOrder(new Order { UserName = "Ricardo Jones", UserPhone = "Test 7", UserAddress = "Test 8", OrderDate = DateTime.Now });
        }

        void CreateTables()
        {
            var sql = @"
                CREATE TABLE [dbo].[Order](
	                [Id] [uniqueidentifier] NOT NULL,
	                [UserName] [nvarchar](max) NULL,
	                [UserPhone] [nvarchar](max) NULL,
	                [UserAddress] [nvarchar](max) NULL,
	                [OrderDate] [datetime] NULL,
                    [Cookie] [nvarchar](max) NULL,
                 CONSTRAINT [PK_Order] PRIMARY KEY CLUSTERED 
                (
	                [Id] ASC
                )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
                ) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
            ";

            using (SqlCommand sqlCommand = Connection.CreateCommand())
            {
                sqlCommand.CommandText = sql;

                ExecuteTransaction(sqlCommand);
            }
        }

        public string AddOrder(Order order)
        {
            var sql = @"INSERT INTO [dbo].[Order] ([Id],[UserName],[UserPhone],[UserAddress],[OrderDate],[Cookie])VALUES(@Id,@UserName,@UserPhone,@UserAddress,@OrderDate,@Cookie)";

            Guid id = Guid.NewGuid();
            string cookie = order.OrderDate.ToString("yyyyMMddHHmmss") + GenerateSecureRandom(128);

            using (SqlCommand sqlCommand = Connection.CreateCommand())
            {
                sqlCommand.CommandText = sql;

                sqlCommand.Parameters.AddWithValue("@Id", id);
                sqlCommand.Parameters.AddWithValue("@UserName", order.UserName);
                sqlCommand.Parameters.AddWithValue("@UserPhone", order.UserPhone);
                sqlCommand.Parameters.AddWithValue("@UserAddress", order.UserAddress);
                sqlCommand.Parameters.AddWithValue("@OrderDate", order.OrderDate);
                sqlCommand.Parameters.AddWithValue("@Cookie", cookie);

                ExecuteTransaction(sqlCommand);
            }

            return cookie;
        }

        void ExecuteTransaction(SqlCommand sqlCommand)
        {
            using (SqlTransaction transaction = Connection.BeginTransaction())
            {
                sqlCommand.Transaction = transaction;

                try
                {
                    sqlCommand.ExecuteNonQuery();

                    transaction.Commit();
                }
                catch (Exception ex)
                {
                    transaction.Rollback();
                    throw ex;
                }
            }
        }

        public void Dispose()
        {
            if (Connection.State != ConnectionState.Closed)
            {
                Connection.Close();
            }

            Connection.Dispose();
        }

        public List<Order> GetPreviousOrders()
        {
            var orders = new List<Order>();

            var sql = "select top 5 UserName, UserPhone, UserAddress, OrderDate from [dbo].[Order] order by OrderDate desc";

            using (SqlCommand sqlCommand = Connection.CreateCommand())
            {
                sqlCommand.CommandText = sql;

                using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                {
                    while (sqlDataReader.Read())
                    {
                        var order = new Order
                        {
                            UserName = sqlDataReader["UserName"].ToString(),
                            OrderDate = Convert.ToDateTime(sqlDataReader["OrderDate"])
                        };

                        orders.Add(order);
                    }
                }
            }

            return orders;
        }

        public Order GetOrderByCookie(string cookie)
        {
            var sql = "select top 1 UserName, UserPhone, UserAddress, OrderDate from [dbo].[Order] where Cookie = @Cookie";

            using (SqlCommand sqlCommand = Connection.CreateCommand())
            {
                sqlCommand.CommandText = sql.Replace("@Cookie", cookie);

                using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                {
                    if (sqlDataReader.Read())
                    {
                        var order = new Order
                        {
                            UserName = sqlDataReader["UserName"].ToString(),
                            OrderDate = Convert.ToDateTime(sqlDataReader["OrderDate"]),
                            UserAddress = sqlDataReader["UserAddress"].ToString(),
                            UserPhone = sqlDataReader["UserPhone"].ToString()
                        };

                        return order;
                    }
                }
            }

            return null;
        }

        public List<Order> GetAllOrders()
        {
            var orders = new List<Order>();

            var sql = "select UserName, UserPhone, UserAddress, OrderDate from [dbo].[Order] order by OrderDate desc";

            using (SqlCommand sqlCommand = Connection.CreateCommand())
            {
                sqlCommand.CommandText = sql;

                using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                {
                    while (sqlDataReader.Read())
                    {
                        var order = new Order
                        {
                            UserName = sqlDataReader["UserName"].ToString(),
                            OrderDate = Convert.ToDateTime(sqlDataReader["OrderDate"]),
                            UserAddress = sqlDataReader["UserAddress"].ToString(),
                            UserPhone = sqlDataReader["UserPhone"].ToString()
                        };

                        orders.Add(order);
                    }
                }
            }

            return orders;
        }

        string GenerateSecureRandom(int length)
        {
            RNGCryptoServiceProvider rngCryptoServiceProvider = new RNGCryptoServiceProvider();
            byte[] randomBytes = new byte[length];
            rngCryptoServiceProvider.GetBytes(randomBytes);
            return Convert.ToBase64String(randomBytes);
        }
    }
}







解決方案1-htmlencode

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        public Order GetOrderByCookie(string cookie)
        {
            var sql = "select top 1 UserName, UserPhone, UserAddress, OrderDate from [dbo].[Order] where Cookie = @Cookie";

            using (SqlCommand sqlCommand = Connection.CreateCommand())
            {
                sqlCommand.CommandText = sql.Replace("@Cookie", HttpUtility.HtmlEncode(cookie));

                using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                {
                    if (sqlDataReader.Read())
                    {
                        var order = new Order
                        {
                            UserName = sqlDataReader["UserName"].ToString(),
                            OrderDate = Convert.ToDateTime(sqlDataReader["OrderDate"]),
                            UserAddress = sqlDataReader["UserAddress"].ToString(),
                            UserPhone = sqlDataReader["UserPhone"].ToString()
                        };

                        return order;
                    }
                }
            }

            return null;
        }


解決方案2-黑名單取代


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        public Order GetOrderByCookie(string cookie)
        {
            var sql = "select top 1 UserName, UserPhone, UserAddress, OrderDate from [dbo].[Order] where Cookie = @Cookie";

            using (SqlCommand sqlCommand = Connection.CreateCommand())
            {
                sqlCommand.CommandText = sql.Replace("@Cookie", RemoveSqlSpecialCharacters(cookie));

                using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                {
                    if (sqlDataReader.Read())
                    {
                        var order = new Order
                        {
                            UserName = sqlDataReader["UserName"].ToString(),
                            OrderDate = Convert.ToDateTime(sqlDataReader["OrderDate"]),
                            UserAddress = sqlDataReader["UserAddress"].ToString(),
                            UserPhone = sqlDataReader["UserPhone"].ToString()
                        };

                        return order;
                    }
                }
            }

            return null;
        }

        string RemoveSqlSpecialCharacters(string str)
        {
            var specialCharacters = new char[]
            {
                ' ', '\'', '"', '(', ')', '[', ']'
            };

            string resultStr = str;

            foreach (char character in specialCharacters)
                resultStr = resultStr.Replace(character.ToString(), string.Empty);

            return resultStr;
        }



(O)解決方案3-參數化串入

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        public Order GetOrderByCookie(string cookie)
        {
            var sql = "select top 1 UserName, UserPhone, UserAddress, OrderDate from [dbo].[Order] where Cookie = @Cookie";

            using (SqlCommand sqlCommand = Connection.CreateCommand())
            {
                sqlCommand.CommandText = sql;

                sqlCommand.Parameters.AddWithValue("@Cookie", cookie);

                using (SqlDataReader sqlDataReader = sqlCommand.ExecuteReader())
                {
                    if (sqlDataReader.Read())
                    {
                        var order = new Order
                        {
                            UserName = sqlDataReader["UserName"].ToString(),
                            OrderDate = Convert.ToDateTime(sqlDataReader["OrderDate"]),
                            UserAddress = sqlDataReader["UserAddress"].ToString(),
                            UserPhone = sqlDataReader["UserPhone"].ToString()
                        };

                        return order;
                    }
                }
            }

            return null;
        }







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