Re: [PATCH] Smackv10: Smack rules grammar + their stateful parser

[Tetsuo Handa]

Linus Torvalds wrote:
> I personally think string parsers are *much* better than the alternatives 
> (which basically boil down to nasty binary interfaces)
Me too.

> Binary structures and ioctl's are *much* worse. They are totally 
> undebuggable with generic tools (think "echo" or "strace"), and they are a 
> total nightmare to parse across architectures and pointer sizes.
Not only pointer sizes bugs, but also checking pointer address costs.
For binary policy, we have to examine ->next pointer is valid or not.
We can't blindly use address supplied from userland.

I have encountered mismatch of kernel version and AppArmor's policy parser version
when I just updated only kernel. As a result, the segmentation faults rushed toward me.
 From this experience, TOMOYO still uses string parser in the kernel.
If a parser doesn't consume much stack (i.e. call functions recursively), I think it is no problem.

Thanks.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/