I have a Microsoft SQL server database and a set of users.
Now in my app I want to make some functionality only visible, if the user has entered username and password with certain rights (admin).
Since the databases and the usernames and their rights can change, how do i check what permissions/rights an Microsoft SQL server user has?
You can check current user's right on certain securables using [sys.fn_mypermissions][1] which returns all permission on the securable. You can also check a specific permission with HAS_PERMS_BY_NAME. Eg. you can check for CONTROL SERVER permission which implies an administrator is logged in:
SELECT HAS_PERMS_BY_NAME(null, null, 'CONTROL SERVER');
The simplest way to do this is using the IS_MEMBER('rolename') function, that checks whether the user is in the role/group 'db_owner'. The function will perform a check at database level, and returns 1 (Int32), if the user has the specified role.
If you need to check at server level, you can use the IS_SRVROLEMEMBER function. Both are available since SQL Server 2005.
I'm not entirely certain that I understand your problem definition however assuming I do.....
I would suggest that you create a SQL Server Database Role that you can add the relevant application users to, perhaps via some group membership maintained within the App (or a Windows Domain Group). You can use the group to Role mapping to independently manage user membership, from managing the relevant permissions to securables within the database via the Role.
This way, you just need to check that an application User is a member of the relevant application or windows group, without the need to query the security configuration of SQL Server.
Related
I am trying to provide DBAdmin privilege for a user on multiple databases.
I know how to do from on premises SQL database, I can directly map the user to required databases.
Can anyone let me know how to do it in Azure managed instance. Since the added user is external user, can,t see it in the Logins to map the user.
I have like 100 databases on which the user should have db admin right. Is there a easiest way to do that?
You can use an Azure Active Directory Login
eg
CREATE LOGIN [someuser#somecompany.onmicrosoft.com] FROM EXTERNAL PROVIDER
then create users mapped to this login in the appropriate databases, or make this login a sysadmin. Not sure if this shows up in SSMS, as it was added relatively recently. So you may have to create the users and grant them permissions in the target databases in TSQL, as per: https://learn.microsoft.com/en-us/azure/sql-database/sql-database-managed-instance-aad-security-tutorial
So I wanted to know if there is an acceptable method to Allow SQL Injection.
Example:
Limit permissions on the table(s)/database(s)
Why you ask?
My employer wanted to devise a way to test the skills of applicants, one suggestion was to allow resume submissions via SQL Injection.
Any thoughts? suggestions?
You could use roles. Create a role for the web application (or whatever) that is used to connect to the database. Limit this role to only permit INSERT and access to necessary tables for applying. Applicants with access to your database through the application could then only use SQL injections to add their resume.
It may be possible for someone more talented in SQL to use injections in a way that increases the role's permission. But I think if the role had limited access to only specific tables and didn't have CREATE or GRANT privileges, the user wouldn't be able to create new roles.
Here is some information on roles to get you started:
Adding Roles to MySQL with MySQL Workbench
Creating Roles in PostgreSQL
GRANT command - used to add privileges to users on table, database, etc. This page is for PostgreSQL, but MySQL is very similar (see this SO answer)
Given that the reason behind this is to test people's ability, create a database with data you can afford to lose. Set up a form that posts to a coldfusion or php or java or .net or some other type of page which connects to that database.
On the form, put a textarea and submit button. On the form target page, log what they put in the textarea. Compare the log to the database to see how it turned out.
Then test to your heart's delight.
As per requirement i need to get the information whether an user is present in given database or not. Whether there is any stored procedure which i can use to get this information of user. I just want to check whether user is present in given database, and proceed further with my usage.
I am using MSSQL Server 2005.
Also i need another information, there is on method LastErrorMessage() to get the last error message in ADO. is there any method to get the error number.
Thanks,
Santhosha
SQL Server has logins (server level) and users (database level). Users are permissioned on databases/database objects and are mapped (well not neccessarily) to logins (roles are also at database level).
users are available from the sys.database_principals system view in each database
logins are available from the sys.server_principals
You need to be aware that you can only see objects/principals which the user you are using to connect to SQL server has permission to see. So a user might exist, even if you don't see it in the views.
I'm quite new to Microsoft SQL Server. I have some experience with MySQL, and there you have a user with privileges, if I understand things right; these privileges decide which databases you have access to on the MySQL server.
However now I am in the situation where I have to restore a database on my SQL Server 2005 Express, and this database has it's own users and user password. So if I want to make these users accessible from the outside (so that they can connect to my server), how would I go about that?
To illustrate clearer; say there are two login accounts on the database server "Mike" and "John", and on the database "Animals" there are two users; "Chris" and "Jeff".
I need Jeff to be able to sign in to get access to the database. Is there a good way to make this happen without creating new users/logins? And if not, what is the best/most common solution?
I would really appreciate any helpful input on this!
One server-level object (login) is mapped to multiple database-level objects (users).
A login cannot be mapped to more than one user within a database, but can be mapped to at most one user in each database.
Therefore, you need to create new logins for those users, but map them to existing users. This is done with ALTER USER command. Or, if you don't have any use for the Mike and John logins apart from mapping them to those existing users, you can do so, too.
Any user needing to access a database needs to either have their own login, or you can create a login for a Windows security group and grant access that way to a whole set of users. Then if you need to give access to more users in the future you can just add them to the windows security group.
I have recently been running into many different areas of SQL Server that I normally don't mess with. One of them that has me confused is the area of Logins and Users. Seems like it should be a pretty simple topic...
It appears that each login can only have 1 user and each user can only have 1 login.
A login can be associated to multiple tables thus associating that user to many tables.
So my question is why even have a login and a user? they seem to be pretty much one in the same. What are the differences, or what is it that I seem to be missing?
A "Login" grants the principal entry into the SERVER.
A "User" grants a login entry into a single DATABASE.
One "Login" can be associated with many users (one per database).
Each of the above objects can have permissions granted to it at its own level. See the following articles for an explanation of each
Principals
Database Users
One reason to have both is so that authentication can be done by the database server, but authorization can be scoped to the database. That way, if you move your database to another server, you can always remap the user-login relationship on the database server, but your database doesn't have to change.
I think there is a really good MSDN blog post about this topic by Laurentiu Cristofor:
The first important thing that needs to be understood about SQL Server
security is that there are two security realms involved - the server
and the database. The server realm encompasses multiple database
realms. All work is done in the context of some database, but to get
to do the work, one needs to first have access to the server and then
to have access to the database.
Access to the server is granted via logins. There are two main
categories of logins: SQL Server authenticated logins and Windows
authenticated logins. I will usually refer to these using the shorter
names of SQL logins and Windows logins. Windows authenticated logins
can either be logins mapped to Windows users or logins mapped to
Windows groups. So, to be able to connect to the server, one must have
access via one of these types or logins - logins provide access to the
server realm.
But logins are not enough, because work is usually done in a database
and databases are separate realms. Access to databases is granted via
users.
Users are mapped to logins and the mapping is expressed by the SID
property of logins and users. A login maps to a user in a database if
their SID values are identical. Depending on the type of login, we can
therefore have a categorization of users that mimics the above
categorization for logins; so, we have SQL users and Windows users and
the latter category consists of users mapped to Windows user logins
and of users mapped to Windows group logins.
Let's take a step back for a quick overview: a login provides access
to the server and to further get access to a database, a user mapped
to the login must exist in the database.
that's the link to the full post.
In Short,
Logins will have the access of the server.
and
Users will have the access of the database.
I think this is a very useful question with good answer. Just to add my two cents from the MSDN Create a Login page:
A login is a security principal, or an entity that can be authenticated by a secure system. Users need a login to connect to SQL Server. You can create a login based on a Windows principal (such as a domain user or a Windows domain group) or you can create a login that is not based on a Windows principal (such as an SQL Server login).
Note:
To use SQL Server Authentication, the Database Engine must use mixed mode authentication. For more information, see Choose an Authentication Mode.
As a security principal, permissions can be granted to logins. The scope of a login is the whole Database Engine. To connect to a specific database on the instance of SQL Server, a login must be mapped to a database user. Permissions inside the database are granted and denied to the database user, not the login. Permissions that have the scope of the whole instance of SQL Server (for example, the CREATE ENDPOINT permission) can be granted to a login.
Graph on logins / users from MS sql-docs