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Message-ID: <581C5CDF.1080608@oracle.com>
Date: Fri, 4 Nov 2016 15:33:11 +0530
From: Vaishali Thakkar <vaishali.thakkar@...cle.com>
To: Mark Rutland <mark.rutland@....com>
Cc: Kees Cook <keescook@...omium.org>,
"kernel-hardening@...ts.openwall.com" <kernel-hardening@...ts.openwall.com>,
Al Viro <viro@...iv.linux.org.uk>, David Windsor <dwindsor@...il.com>
Subject: Re: [RFC PATCH] lib: Harden
csum_partial_copy_from_user
On Thursday 03 November 2016 11:35 PM, Mark Rutland wrote:
> On Thu, Nov 03, 2016 at 10:26:41AM +0530, Vaishali Thakkar wrote:
>> On Thursday 03 November 2016 09:53 AM, Mark Rutland wrote:
>>> On Thu, Nov 03, 2016 at 07:44:35AM +0530, Vaishali Thakkar wrote:
>>>> On Thursday 03 November 2016 03:29 AM, Kees Cook wrote:
>>>>> On Wed, Nov 2, 2016 at 2:44 PM, Mark Rutland <mark.rutland@....com> wrote:
>>>>>> I know that both arm64 and x86 have a check_object_size() call in their
>>>>>> __copy_from_user() implementations.
>>>
>>>>>> Is that missing on some architectures?
>
>>> Looking again, a grep shows many (even those with MMUs) don't do anything at
>>> all in v4.9-rc2:
>>>
>>> [mark@...oulade:~/src/linux]% for ARCH in arch/*; do
>>> printf "%d %s\n" $(git grep check_object_size -- "${ARCH}" | wc -l) ${ARCH};
>>> done | sort -n
>
>> Hmm, should we go for sending patches for them? [atleast for the ones with MMUs
>> and then may be maintainers/developers can check the change]
>
> If Al's uaccess unification work is arriving shortly, sending patches for those
> in parallel is just going to make matters more painful.
>
> So it really depends on when that's likely to appear.
Makes sense.
>> Also, I think same goes for the the kasan_check. We have only arm64 and x86
>> with these checks.
>
> Yes. I'd hoped to collect all of those behind a common helper, something like:
>
> static inline void check_uaccess_read(void *kaddr, const void __user *uaddr, unsigned long n)
> {
> kasan_check_write(kaddr, n);
> check_object_size(kaddr, n, false);
> any_uaddr_sanity_check(uaddr, n);
> }
Ok, sounds reasonable.
Thanks.
> Thanks,
> Mark.
>
--
Vaishali
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