Messages in this thread | | | Subject | Re: [PATCH 11/18] maccess: remove strncpy_from_unsafe | From | Daniel Borkmann <> | Date | Thu, 14 May 2020 12:27:42 +0200 |
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On 5/14/20 11:44 AM, Masami Hiramatsu wrote: > On Wed, 13 May 2020 19:43:24 -0700 > Linus Torvalds <torvalds@linux-foundation.org> wrote: >> On Wed, May 13, 2020 at 6:00 PM Masami Hiramatsu <mhiramat@kernel.org> wrote: >>> >>>> But we should likely at least disallow it entirely on platforms where >>>> we really can't - or pick one hardcoded choice. On sparc, you really >>>> _have_ to specify one or the other. >>> >>> OK. BTW, is there any way to detect the kernel/user space overlap on >>> memory layout statically? If there, I can do it. (I don't like >>> "if (CONFIG_X86)" thing....) >>> Or, maybe we need CONFIG_ARCH_OVERLAP_ADDRESS_SPACE? >> >> I think it would be better to have a CONFIG variable that >> architectures can just 'select' to show that they are ok with separate >> kernel and user addresses. >> >> Because I don't think we have any way to say that right now as-is. You >> can probably come up with hacky ways to approximate it, ie something >> like >> >> if (TASK_SIZE_MAX > PAGE_OFFSET) >> .... they overlap .. >> >> which would almost work, but.. > > It seems TASK_SIZE_MAX is defined only on x86 and s390, what about > comparing STACK_TOP_MAX with PAGE_OFFSET ? > Anyway, I agree that the best way is introducing a CONFIG.
Agree, CONFIG knob that archs can select feels cleanest. Fwiw, I've cooked up fixes for bpf side locally here and finishing up testing, will push out later today.
Thanks, Daniel
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