/// <summary>
/// Queries a string-valued context attribute by the named attribute.
/// </summary>
/// <param name="attrib">The string-valued attribute to query.</param>
/// <returns></returns>
private string QueryContextString(ContextQueryAttrib attrib)
{
SecPkgContext_String stringAttrib;
SecurityStatus status = SecurityStatus.InternalError;
string result = null;
bool gotRef = false;
if (attrib != ContextQueryAttrib.Names && attrib != ContextQueryAttrib.Authority)
{
throw new InvalidOperationException("QueryContextString can only be used to query context Name and Authority attributes");
}
stringAttrib = new SecPkgContext_String();
RuntimeHelpers.PrepareConstrainedRegions();
try
{
this.ContextHandle.DangerousAddRef(ref gotRef);
}
catch (Exception)
{
if (gotRef)
{
this.ContextHandle.DangerousRelease();
gotRef = false;
}
throw;
}
finally
{
if (gotRef)
{
status = ContextNativeMethods.QueryContextAttributes_String(
ref this.ContextHandle.rawHandle,
attrib,
ref stringAttrib
);
this.ContextHandle.DangerousRelease();
if (status == SecurityStatus.OK)
{
result = Marshal.PtrToStringUni(stringAttrib.StringResult);
ContextNativeMethods.FreeContextBuffer(stringAttrib.StringResult);
}
}
}
if (status == SecurityStatus.Unsupported)
{
return(null);
}
else if (status != SecurityStatus.OK)
{
throw new SSPIException("Failed to query the context's associated user name", status);
}
return(result);
}
internal static extern SecurityStatus QueryContextAttributes_String(
ref RawSspiHandle contextHandle,
ContextQueryAttrib attrib,
ref SecPkgContext_String names
);
