在 2023/2/22 4:26, Seth Jenkins 写道:
> So you are letting an opaque US government agency, and random third
> party companies, dictate your company's internal engineering policies
> and resource allocations? That feels very very odd and ripe for abuse.
I wholeheartedly agree with gregkh that the CVE system is flawed in
numerous ways and generates many false positives, however in this case,
this issue is a real issue with real security impact that received a
real patch upstream. The idea of backporting this to earlier kernels
probably warrants discussion if someone is willing to bite off that
work. But this gets into the fuzzy "backporting exploit mitigations to
stable" conversation.
> And are you sure this can really happen? Have you proven this?
Yes this can really, provably, happen:
https://googleprojectzero.blogspot.com/2022/12/exploiting-CVE-2022-42703-bringing-back-the-stack-attack.html
<https://googleprojectzero.blogspot.com/2022/12/exploiting-CVE-2022-42703-bringing-back-the-stack-attack.html>
> And why is this really an issue, KAS[L]R is a known-weak-defense and
almost
> useless against local attacks.
Granted, Peter Z's fix does help to mitigate the impact from remote
attackers but yes this fix does not resolve the security impact from
local exploits.
Thank you seth.
Yes, for this specific CVE issue, KASLR is indeed a mitigation measure.
On Tue, Feb 21, 2023 at 7:30 AM Tong Tiangen <tongtiangen@xxxxxxxxxx
<mailto:tongtiangen@xxxxxxxxxx>> wrote:
在 2023/2/21 18:40, Greg KH 写道:
> On Tue, Feb 21, 2023 at 05:19:42PM +0800, Tong Tiangen wrote:
>>
>>
>> 在 2023/2/21 16:40, Greg KH 写道:
>>> On Tue, Feb 21, 2023 at 03:46:27PM +0800, Tong Tiangen wrote:
>>>>
>>>>
>>>> 在 2023/2/21 15:30, Greg KH 写道:
>>>>> On Tue, Feb 21, 2023 at 03:19:05PM +0800, Tong Tiangen wrote:
>>>>>> Hi peter:
>>>>>>
>>>>>> Do you have any plans to backport this patch[1] to the
stable branch of the
>>>>>> lower version, such as 4.19.y ?
>>>>>
>>>>> Why? That is a new feature for 6.2 why would it be needed to fix
>>>>> anything in really old kernels?
>>>>
>>>> Hi Greg:
>>>>
>>>> This patch fix CVE-2023-0597[1],
>>>
>>> The kernel developers do not care about CVEs as they are almost
always
>>> invalid and do not mean anything,
>>
>> Ok, thanks.
>>
>>
>>> sorry. It is well known that, companies like Red Hat use them
to make
>>> up for broken internal engineering policies.
>>
>> Yeah, For company's internal engineering policies, the CVE with
certain
>> impact must be repaired.
>
> So you are letting an opaque US government agency, and random third
> party companies, dictate your company's internal engineering policies
> and resource allocations? That feels very very odd and ripe for
abuse.
>
> Also note that MITRE refuses to allocate CVEs for many real kernel
> issues for unknown reasons, (i.e. they reject all of my requests), so
> you are getting only a small subset of real issues here.
>
> Also, how do you handle revocation of CVEs that are obviously invalid
> and/or don't actually do anything (like this one?)
>
>>> Are you sure this really is a valid problem that must be fixed
in older
>>> kernels?
>>>
>>>> this CVE report a flaw possibility of memory leak. And this is
>>>> important for some products using this stable version.
>>>
>>> What exact memory leak are you referring to?
>>
>> Sorry for Inaccurate description, the memory leak means: a potential
>> security risk of kernel memory information disclosure caused by no
>> randomization of the exception stacks.
>
> And are you sure this can really happen? Have you proven this?
>
> And why is this really an issue, KASR is a known-week-defense and
almost
> useless against local attacks.
>
> Anyway, please provide working patches if you think this really is an
> issue.
>
> And please revisit your company's policies, they do not seem very
sane :)
Hi Greg:
Thanks for these very useful suggestions and we will revisit our
policies :)
Thanks,
Tong
.
>
> thanks,
>
> greg k-h
> .
