mysqlsql 注入攻击

# ### sql 注入攻击
"""
# 创建一张表
create table usr_pwd(
id int unsigned primary key auto_increment,
username varchar(255) not null,
password varchar(255) not null
)
"""

# (1) sql注入问题
'''
import pymysql
user = input("user>>>:").strip()
pwd = input("password>>>:").strip()

conn = pymysql.connect(host="127.0.0.1",user="root",password="123456",database="db7")
cursor = conn.cursor()
sql = "select * from usr_pwd where username='%s' and password = '%s' " % (user,pwd)

"""
swrwer234' or 2=2 -- sdfsdf
select * from usr_pwd where username='swrwer234' or 2=2 -- sdfsdf' and password = '2342342' -- 代表的是后面的代码注释掉
"""
print(sql)
res = cursor.execute(sql)
print(res) # 返回的条数

if res:
print("登录成功")
else:
print("登陆失败")

cursor.close()
conn.close()
'''
# (2) 解决办法
"""
使用预处理机制,可以避免绝大多数的sql注入问题;
execute 默认参数是一个sql语句 ,如果把sql语句和参数值分开执行,就开启预处理
execute(sql,(参数1,参数2,参数3 ..... ) )
"""
import pymysql
user = input("user>>>:").strip()
pwd = input("password>>>:").strip()

conn = pymysql.connect(host="127.0.0.1",user="root",password="123456",database="db7")
cursor = conn.cursor()
sql = "select * from usr_pwd where username=%s and password = %s"
res = cursor.execute( sql , (user,pwd) )

if res:
print("登录成功")
else:
print("登录失败")

cursor.close()
conn.close()