permission problem on dynamic query running in a stored procedure - sql

i have this stored procedure, doing a select query with couple of inner joins (one of the tables is in another db). Now, i had to write this query as dynamic cause first i had to find which db the select query should run. Anyway, none of the tables have permissions on them, just giving permission to the stored procedure for the database role "personel" (which includes everyone).
But now, someone with a personel role runs this stored proc, they are getting the error "The SELECT permission was denied on the object 'tbl_table', database 'Db', schema 'dbo'." no difference in the schema, and there are other procs using the same table that are running normally.
Can using a dynamic query (exec (Use DB; select ...) ) be the reason for this? Like cause it is dynamic, i should give permissions to the tables also ?
Thanks

The short answer is yes.
When you compile a stored procedure, permissions of the user/login creating the stored procedure are checked. When someone else executes it, their ability to read those tables is no longer relevant (in most cases), but rather just their ability to execute the SP.
When executing the dynamic code, however, the permissions regarding the tables have to be checked there and then. This means that the executing user's permissions are being checked.

Yes, this can be the reason. Read this to get an explanation and a possible solution.

Related

Stored procedure not compiling with different USE clauses

I have several views in Database 1 and I wrote a stored procedure in database 2. The stored procedure in database 2 references several tables in database 1.
For some reason when I have:
USE Database1
GO
while testing, it works completely fine. But when I use
USE Database2
GO
the stored procedure doesn't compile. No warnings, just continues to spin. The first case only takes about 1 second to run.
Anyone know what could possibly be the issue? When I attempt to run similar stored procedures in database2 that use the same references to database1 it works fine. Also, they are on the same server in SQL Server.
Sorry I am unable to post the code.
SQL Server has to take out locks on the objects so it can create a query plan. It either cannot connect to the database or cannot take the locks it needs.

Restore stored procedure from corrupt database

I'm working on trying to salvage as much as possible from a corrupt database. I can query tables, but not see their metadata (properties, script as...) - all those actions result in
The Table ... does not exist on the server
errors when it clearly does, since Select * from ... works.
I was able to create a new database and get both schema and data by doing:
select *
into newdB.dbo.table
from corruptdb.dbo.table
WHEW!
Now on to stored procedures. I can execute them, but I can't modify or script as. Any suggestions as to how to save those??
Thanks
Try sp_helptext to see if you can get the source of the stored procedure back.
(see http://msdn.microsoft.com/en-us/library/ms176112.aspx).
If that doesn't work, the db likely (though not guaranteed - it's corrupt, after all!) does not have the source for the stored procedure.
exec sp_helptext 'some_procedure`
Of course, the correct answer is: restore from backup.

SQL Server Update Permissions

I'm currently working with SQL Server 2008 R2, and I have only READ access to a few tables that house production data.
I'm finding that in many cases, it would be extremely nice if I could run something like the following, and get the total record count back that was affected :
USE DB
GO
BEGIN TRANSACTION
UPDATE Person
SET pType = 'retailer'
WHERE pTrackId = 20
AND pWebId LIKE 'rtlr%';
ROLLBACK TRANSACTION
However, seeing as I don't have the UPDATE permission, I cannot successfully run this script without getting :
Msg 229, Level 14, State 5, Line 5
The UPDATE permission was denied on the object 'Person', database 'DB', schema 'dbo'.
My questions :
Is there any way that my account in SQL Server can be configured so that if I want to run an UPDATE script, it would automatically be wrapped in a transaction with an rollback (so no data is actually affected)
I know I could make a copy of that data and run my script against a local SSMS instance, but I'm wondering if there is a permission-based way of accomplishing this.
I don't think there is a way to bypass SQL Server permissions. And I don't think it's a good idea to develop on production database anyway. It would be much better to have development version of the database you work with.
If the number of affected rows is all you need then you can run select instead of update.
For example:
select count(*)
from Person
where pTrackId = 20
AND pWebId LIKE 'rtlr%';
If you are only after the amount of rows that would be affected with this update, that would be same amount of rows that currently comply to the WHERE clause.
So you can just run a SELECT statement as such:
SELECT COUNT(pType)
FROM Person WHERE pTrackId = 20
AND pWebId LIKE 'rtlr%';
And you'd get the resulting potential rows affected.
1.First Login as admin in sqlserver
2.Goto login->your name->Check the roles.
3.IF u have write access,then you can accomplish the above task.
4.If not make sure you grant access to write.
If it's strictly necessary to try the update, you could write a stored procedure, accepting dynamic SQL as a string (Your UPDATE query) and wrapping the dynamic SQL in a transaction context which is then rolled back. Your account could then be granted access to that stored procedure.
Personally, I think that's a terrible idea, and incredibly unsafe - some queries break out of such transaction contexts (e.g. ALTER TABLE). You may be able to block those somehow, but it would still be a security/auditing problem.
I recommend writing a query to count the relevant rows:
SELECT COUNT(*)
FROM --tables
WHERE --your where clause
-- any other clauses here e.g. GROUP BY, HAVING ...

User Granted Access to Stored Procedure but Can't Run Query

I am working on a product that runs an SQL server which allows some applications to login and their logins are granted permission to run a stored procedure- AND NOTHING ELSE. The stored procedure is owned by an admin; the stored procedure takes a query and executes it, then the results are returned to the application.
Unfortunately I can't figure out why the application can call the stored procedure to which it's granted access, but the stored procedure cannot execute the SQL statement which was passed into it.
The stored procedure executes the passed in query when I'm logged in as an admin, but when I log in as the limited user it throws an exception in the execute statement.
For example:
EXEC [Admin].[STORED_PROC] #SQL_STATEMENT = 'SELECT * FROM table_x'
the STORED_PROC looks something like this:
BEGIN TRY
EXEC (#SQL_STATEMENT)
END TRY
BEGIN CATCH
-- some logging when an exception is caught, and the exception is caught here!!!
END CATCH
There is nothing inside the the try catch statement except that EXEC... and the SQL_STATEMENT works when I'm logged in as the Admin, but not when I'm logged in as the User.
Can anybody help me figure out what permissions I need to set in order to allow the User to run queries through the stored proc only?
So there have been some comments about allowing raw SQL statements to be executed via stored proc defeats the purpose of using a stored proc... but in reality what we're actually doing is we're passing an encrypted SQL statement into the stored proc and the stored proc gets the statement decrypted and THEN it executes it.
So yes, in reality raw SQL statements are not secure and they defeat the purpose of stored procs, but I don't know how to encrypt SQL queries that are passed through ODBC and run against a pre-2005 SQL Server.
In any case, I tried to put up some minimal safeguards to at least have some basic security.
Since you are using dynamic sql, SQL server can't tell which tables you are using, so you have to grant SELECT rights to all the tables as well
Users also need to have SELECT grant on the tables
Allowing raw SQL to be passed into a stored procedure and then executing is the very essence of data insecurity.
SQL Server security is structured so that arbitrary bits of SQL execute in their own security context. If you don't have the permission to run the query ad hoc, you also don't have the permission to run it through a stored procedure. In this, SQL Server is saving you from yourself.
Since your system allows access to stored procs and nothing else (which is good for security purposes and should not be changed) then you simply cannot under any circumstances use dynamic SQL because the rights are not at the table level and your dbas are unlikely to change that. This is not only to prevent SQL Injection attacks but to prevent possible internal fraud so any workplace which has considered this important will not be willing to compromise to make life easier for you. You simply need to redesign to never do anything dynamically. You have no other choice. If you write the procs to do what you want it to do in the first place, there is no need to send encypted sql.
When dynamic SQL is used through EXEC or sp_executesql within an SP, the EXEC permissions on the SP do not allow you to run arbitrary code in the dynamic sql. You either need to grant SELECT (yuck), or you might be able to impersonate another user using EXECUTE AS or SETUSER.
When normal SQL is used, EXEC permissions works fine, overridding ungranted SELECT persmissions. If you have DENY, though, I believe that trumps it.
Having said that, I'm still not sure you should use EXECUTE AS when the source of the SQL is outside the SP (or outside the database). For code-generation or dynamic sql which is safe from outside influence, EXECUTE AS can be a useful tool
This is most likely because of different schemas i.e. the user who logs in is not part of the Admin schema, or at least I would hope not.
The security technique that permits the type of access you are looking to achieve, i.e. to permit access to objects that are owned by the same schema, is called Ownership Chaining.
This principle is not best explained in a post.
Here is a link from Microsoft that explains the concept.
http://msdn.microsoft.com/en-us/library/ms188676(SQL.90).aspx
Here is a an outstanding article on security that provides examples and walkthroughs, for ownership chaining, amongst other techniques.
http://www.sommarskog.se/grantperm.html
I hope this is clear and assists you but please feel free to pose further questions.
Cheers, John

I traced a Stored Procedure as shown in the SQL Server 2005 Profiler. It's not found but works. Why?

This is pretty weird.
I have my Profiler open and it obviously shows that a stored procedure is called. I open the database and the SP list, but the SP doesn't exist. However, there's another SP whose name is the same except it has a prefix 'x'
Is SQL Server 2005 mapping the SP name to a different one for security purposes?
EDIT: I found out it's a Synonym, whatever that is.
In general, when you know an object exists because it's been used in a query, and you can't find it in the object tree in Management Studio, you can do this to find it.
select *
from sys.objects
where name = 'THE_NAME_YOU_WANT'
I just checked, and it works with Synonyms.
Possibly silly questions, but just in case... have you refreshed the SP list? Have you checked for a stored procedure of that name under a different owner? If you created the stored procedure without specifying the owner then it could be in the list under your ownership (or not at all if the list is filtered to only "dbo" for example).
You may not have permission to see all the objects in the database
Adding to the previous answers, it could also be under "System Stored Procedures", and if the name of the stored procedure begins with "sp_", it could also be in the master database.
The stored procedure will be inside the database you have selected at time of stored procedure creation. So search inside the database from which it is extracting data, otherwise it will be inside the master database. If still you are not able to find then first number solution is best one. i.e.
select * from sys.objects where name = 'name of stored procedure'