On Sat, 2007-11-17 at 13:04 +0900, Tetsuo Handa wrote: > Hello. > > Trond Myklebust wrote: > > The problem is that you have thrown away the main tool for documenting > > the requirement, and for enforcing correctness (i.e. function argument > > checking by the compiler). > I'm sorry. I wanted to know whether the below approach is possible.
"Possible" is completely irrelevant. The question you _should_ be asking is "is it maintainable". > > The old functions are still there, are still exported, and still take > > the same arguments as before, but you have now added a hidden > > requirement that I have to set last_vfsmount when I call them. If I > > haven't read your patch, and just call one of those vfs_* functions as > > before, without setting last_vfsmount, I break your model, and I won't > > find out until someone reports an obscure bug at runtime. > I don't care if some kernel module calls vfs_* without setting last_vfsmount > because there is no reason to reject requests from kernel code. > Setting last_vfsmount is required for requests from userland process. > This approach makes it possible to > (1) tell whether the vfs_* calls are from userland or kernel > and > (2) leave kernel modules that are not called from userland unchanged. > This is why this patch doesn't and needn't to modify fs/*/ files. I'm confused. How do you tell the difference between a 'userland' request and a 'kernel' request, and why is the latter safe from a security perspective? Trond - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
