netdev - Re: [PATCH bpf-next v3] libbpf: fix compatibility for kernels without need

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:   Fri, 25 Oct 2019 12:30:18 -0700
From:   "Jonathan Lemon" <jonathan.lemon@...il.com>
To:     "Magnus Karlsson" <magnus.karlsson@...el.com>
Cc:     bjorn.topel@...el.com, ast@...nel.org, daniel@...earbox.net,
        netdev@...r.kernel.org, bpf@...r.kernel.org, degeneloy@...il.com,
        john.fastabend@...il.com
Subject: Re: [PATCH bpf-next v3] libbpf: fix compatibility for kernels without
 need_wakeup



On 25 Oct 2019, at 2:17, Magnus Karlsson wrote:

> When the need_wakeup flag was added to AF_XDP, the format of the
> XDP_MMAP_OFFSETS getsockopt was extended. Code was added to the
> kernel to take care of compatibility issues arrising from running
> applications using any of the two formats. However, libbpf was
> not extended to take care of the case when the application/libbpf
> uses the new format but the kernel only supports the old
> format. This patch adds support in libbpf for parsing the old
> format, before the need_wakeup flag was added, and emulating a
> set of static need_wakeup flags that will always work for the
> application.
>
> v2 -> v3:
> * Incorporated code improvements suggested by Jonathan Lemon

Thanks for doing this, Magnus!  It looks much simpler now.


>
> v1 -> v2:
> * Rebased to bpf-next
> * Rewrote the code as the previous version made you blind
>
> Fixes: a4500432c2587cb2a ("libbpf: add support for need_wakeup flag in 
> AF_XDP part")
> Reported-by: Eloy Degen <degeneloy@...il.com>
> Signed-off-by: Magnus Karlsson <magnus.karlsson@...el.com>

Acked-by: Jonathan Lemon <jonathan.lemon@...il.com>