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  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Date:   Fri, 24 Apr 2020 16:05:54 +0200
From:   Toke Høiland-Jørgensen <>
To:     Jesper Dangaard Brouer <>,
Cc:     Toshiaki Makita <>,
        Mao Wenan <>,
        Toshiaki Makita <>,
        Jesper Dangaard Brouer <>,,,,,,
        Daniel Borkmann <>,
        Alexei Starovoitov <>,
        John Fastabend <>,
        Alexander Duyck <>,
        Jeff Kirsher <>,
        David Ahern <>,
        Willem de Bruijn <>,
        Ilias Apalodimas <>,
        Lorenzo Bianconi <>,
        Saeed Mahameed <>,
Subject: Re: [PATCH net-next 09/33] veth: adjust hard_start offset on redirect XDP frames

Jesper Dangaard Brouer <> writes:

> When native XDP redirect into a veth device, the frame arrives in the
> xdp_frame structure. It is then processed in veth_xdp_rcv_one(),
> which can run a new XDP bpf_prog on the packet. Doing so requires
> converting xdp_frame to xdp_buff, but the tricky part is that
> xdp_frame memory area is located in the top (data_hard_start) memory
> area that xdp_buff will point into.
> The current code tried to protect the xdp_frame area, by assigning
> xdp_buff.data_hard_start past this memory. This results in 32 bytes
> less headroom to expand into via BPF-helper bpf_xdp_adjust_head().
> This protect step is actually not needed, because BPF-helper
> bpf_xdp_adjust_head() already reserve this area, and don't allow
> BPF-prog to expand into it. Thus, it is safe to point data_hard_start
> directly at xdp_frame memory area.
> Cc: Toshiaki Makita <>
> Fixes: 9fc8d518d9d5 ("veth: Handle xdp_frames in xdp napi ring")
> Reported-by: Mao Wenan <>
> Signed-off-by: Jesper Dangaard Brouer <>
> Acked-by: Toshiaki Makita <>

Acked-by: Toke Høiland-Jørgensen <>

Powered by blists - more mailing lists