netdev - Re: [PATCH net-next 1/4] netlink: truncate overlength attribute list in nla_nest

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Wed, 7 Jun 2023 16:31:48 +0300
From: Gal Pressman <gal@...dia.com>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Edwin Peer <espeer@...il.com>, David Ahern <dsahern@...il.com>,
 netdev <netdev@...r.kernel.org>,
 Andrew Gospodarek <andrew.gospodarek@...adcom.com>,
 Michael Chan <michael.chan@...adcom.com>,
 Stephen Hemminger <stephen@...workplumber.org>,
 Michal Kubecek <mkubecek@...e.cz>
Subject: Re: [PATCH net-next 1/4] netlink: truncate overlength attribute list
 in nla_nest_end()

On 06/06/2023 19:17, Jakub Kicinski wrote:
> On Tue, 6 Jun 2023 11:01:14 +0300 Gal Pressman wrote:
>> On 05/06/2023 22:27, Edwin Peer wrote:
>>> Thanks for the CC, I left Broadcom quite some time ago and am no
>>> longer subscribed to netdev as a result (been living in firmware land
>>> doing work in Rust).
>>>
>>> I have no immediate plans to pick this up, at least not in the short
>>> to medium term. My work in progress was on the laptop I returned and I
>>> cannot immediately recall what solution I had in mind here.
>>
>> Jakub, sorry if this has been discussed already in the past, but can you
>> please clarify what is an accepted (or more importantly, not accepted)
>> solution for this issue? I'm not familiar with the history and don't
>> want to repeat previous mistakes.
> 
> The problem is basically that attributes can only be 64kB and 
> the legacy SR-IOV API wraps all the link info in an attribute.

Isn't that a second order issue? The skb itself is limited to 32kB AFAICT.

>> So far I've seen discussions about increasing the recv buffer size, and
>> this patchset which changes the GETLINK ABI, both of which were nacked.
> 
> Filtering out some of the info, like the stats, is okay, but that just
> increases the limit. A limit still exists.

Any objections to at least take the second patch here?
It doesn't introduce any ABI changes, but will allow 'ip link show' to
work properly (although 'ip -s link show' will remain broken).

>> Having 'ip link show' broken is very unfortunate :\, how should one
>> approach this issue in 2023?
> 
> Sure is, which is why we should be moving away from the legacy SR-IOV
> APIs.

Agreed!
I do not suggest to extend/improve this API, just make sure it's not broken.