netdev - Re: [Patch net 0/3] idr: fix overflow cases on 32-bit CPU

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]

Message-Id: <20190701.193921.1287174101564488400.davem@davemloft.net>
Date:   Mon, 01 Jul 2019 19:39:21 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     willy@...radead.org
Cc:     xiyou.wangcong@...il.com, netdev@...r.kernel.org,
        dcaratti@...hat.com, chrism@...lanox.com
Subject: Re: [Patch net 0/3] idr: fix overflow cases on 32-bit CPU

From: Matthew Wilcox <willy@...radead.org>
Date: Mon, 1 Jul 2019 19:37:30 -0700

> On Mon, Jul 01, 2019 at 07:16:00PM -0700, David Miller wrote:
>> From: Cong Wang <xiyou.wangcong@...il.com>
>> Date: Fri, 28 Jun 2019 11:03:40 -0700
>> 
>> > idr_get_next_ul() is problematic by design, it can't handle
>> > the following overflow case well on 32-bit CPU:
>> > 
>> > u32 id = UINT_MAX;
>> > idr_alloc_u32(&id);
>> > while (idr_get_next_ul(&id) != NULL)
>> >  id++;
>> > 
>> > when 'id' overflows and becomes 0 after UINT_MAX, the loop
>> > goes infinite.
>> > 
>> > Fix this by eliminating external users of idr_get_next_ul()
>> > and migrating them to idr_for_each_entry_continue_ul(). And
>> > add an additional parameter for these iteration macros to detect
>> > overflow properly.
>> > 
>> > Please merge this through networking tree, as all the users
>> > are in networking subsystem.
>> 
>> Series applied, thanks Cong.
> 
> Ugh, I don't even get the weekend to reply?
> 
> I think this is just a bad idea.  It'd be better to apply the conversion
> patches to use XArray than fix up this crappy interface.  I didn't
> reply before because I wanted to check those patches still apply and
> post them as part of the response.  Now they're definitely broken and
> need to be redone.

Please work this out with Cong.

I think his approach is safe for net and thus -stable than an xarray
conversion.