/// <summary>
/// Do an access check between a security descriptor and a token to determine the allowed access.
/// </summary>
/// <param name="sd">The security descriptor</param>
/// <param name="token">The access token.</param>
/// <param name="access_rights">The set of access rights to check against</param>
/// <param name="principal">An optional principal SID used to replace the SELF SID in a security descriptor.</param>
/// <param name="generic_mapping">The type specific generic mapping (get from corresponding NtType entry).</param>
/// <returns>The allowed access mask as a unsigned integer.</returns>
/// <exception cref="NtException">Thrown if an error occurred in the access check.</exception>
public static AccessMask GetAllowedAccess(SecurityDescriptor sd, NtToken token,
AccessMask access_rights, Sid principal, GenericMapping generic_mapping)
{
if (sd == null)
{
throw new ArgumentNullException("sd");
}
if (token == null)
{
throw new ArgumentNullException("token");
}
if (access_rights.IsEmpty)
{
return(AccessMask.Empty);
}
using (SafeBuffer sd_buffer = sd.ToSafeBuffer())
{
using (NtToken imp_token = DuplicateForAccessCheck(token))
{
using (var privs = new SafePrivilegeSetBuffer())
{
int buffer_length = privs.Length;
using (var self_sid = principal != null ? principal.ToSafeBuffer() : SafeSidBufferHandle.Null)
{
NtSystemCalls.NtAccessCheckByType(sd_buffer, self_sid, imp_token.Handle, access_rights,
SafeHGlobalBuffer.Null, 0, ref generic_mapping, privs,
ref buffer_length, out AccessMask granted_access, out NtStatus result_status).ToNtException();
if (result_status.IsSuccess())
{
return(granted_access);
}
return(AccessMask.Empty);
}
}
}
}
}
