T mode for subjects

[IppatsuMan]

Hi all
First: I apologize for my bad english.

From gracldoc.pdf, in the section about subject modes:

* T - Ensures this process can never execute any trojaned code

What does it mean? I know what is a trojaned code (but maybe my definition differs) but how does grsecurity prevent the execution of a trojaned subject? Does it save a hash of the executable file and checks that it is not tampered when it is started?

I've checked the kernel source and it seems that it refers to the GR_NOTROJAN constant, but it seems that this constant isn't used anywhere in the code.

In brief: what does the T mode do to a subject?

Thank you all.

[spender]

It checks all other non-admin subjects and looks to see if any of them allow writing to the subject with the T mode set. This is all done in userland, which is why there's no reference to the mode in the kernel code.

-Brad