Question

How do i mark as assembly as “safe”?

Alternatively, how do i have Visual Studio tell me when something in my assembly is not “safe”?

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Sometimes you cannot use an assembly unless it is “safe” (e.g. from SQL Server).

i would like my assembly to be marked as safe. If my assembly cannot be marked as safe because it’s not safe, i’d like to know how i can know that my assembly is not safe.

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There are some concepts in Visual Studio that seem to relate to safe-ness, that may or may not have anything to do with an assembly being “safe”:

1. Allow unsafe code assembly option:

   

   • What is allowed if i check the allow unsafe code option?
   • What is not allowed if i uncheck the allow unsafe code option?

   • What relation, if any, does “unsafe code” have to do with an assembly being “safe”?

     (i ask because my assembly doesn’t “allow unsafe code”, but allows P/Invoke calls – which i thought was the definition of “unsafe”)

2. ClsCompliant assembly option:

   [assembly: CLSCompliant(true)]
   namespace MyApplication
   

   • What is the relation, if any, does “cls compliant” code have to do with an assembly being “safe”?

3. unsafe code block:

   int error;
   unsafe
   {
       error = 0x80004005;
   }    
   

   The code inside the unsafe block is “unsafe”

4. UnsafeNativeMathods

   Microsoft recommends creating a class called UnsafeNativeMethods that contain unsafe managed code:

   [SuppressUnmanagedCodeSecurity]
   internal static class UnsafeNativeMethods
   {
      ...          
   }
   

   This contrasts with SafeNativeMethods:

   [SuppressUnmanagedCodeSecurity]
   internal static class SafeNativeMethods
   {
      ...          
   }
   

   that contains safe native methods, and NativeMethods:

   internal static class SafeNativeMethods
   {
      ...          
   }
   

   that contain native methods.

How do i mark as assembly as “safe”?

How does SQL know that as assembly is “not safe”?

Answer 1

• Reading from this, the “Safe” for SQL Server is a:

SAFE is the most restrictive permission set.
Code executed by an assembly with SAFE permissions cannot access
external system resources such as files, the network, environment
variables, or the registry

so its about code execution permission set inside SQL Server code domain

• Unsafe flag from VS has nothing to do, basically, with code execution security, but enables non managed code execution. So this about non managed code integration into managed code base

• CLS Compilant attribute as defined here is about defining the code of the assembly marked with that attribute like a code that follows CSL (Common Language Specification) guideline. So this about compilation and code architecture.

How do i mark as assembly as “safe”?

It defined in the first link in this answer and has relation with SQL Server integration.

How does SQL know that as assembly is “not safe”?

Considering description provided: “Creates a managed application module that contains class metadata and managed code as an object in an instance of SQL Server”, SQL Server relays on metadata, that in some fields provides an information about the fact if it is “safe” or not.