netdev - [PATCH bpf-next 0/2] double-fix bpf_test_run + XDP

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Message-Id: <20230316175051.922550-1-aleksander.lobakin@intel.com>
Date:   Thu, 16 Mar 2023 18:50:49 +0100
From:   Alexander Lobakin <aleksander.lobakin@...el.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Martin KaFai Lau <martin.lau@...ux.dev>
Cc:     Alexander Lobakin <aleksander.lobakin@...el.com>,
        Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        Larysa Zaremba <larysa.zaremba@...el.com>,
        Toke Høiland-Jørgensen <toke@...hat.com>,
        Ilya Leoshkevich <iii@...ux.ibm.com>,
        Song Liu <song@...nel.org>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        Jakub Kicinski <kuba@...nel.org>, bpf@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH bpf-next 0/2] double-fix bpf_test_run + XDP_PASS recycling

Enabling skb PP recycling revealed a couple issues in the bpf_test_run
code. Recycling broke the assumption that the headroom won't ever be
touched during the test_run execution: xdp_scrub_frame() invalidates the
XDP frame at the headroom start, while neigh xmit code overwrites 2 bytes
to the left of the Ethernet header. The first makes the kernel panic in
certain cases, while the second breaks xdp_do_redirect selftest on BE.
test_run is a limited-scope entity, so let's hope no more corner cases
will happen here or at least they will be as easy and pleasant to fix
as those two.

Alexander Lobakin (2):
  bpf, test_run: fix crashes due to XDP frame overwriting/corruption
  selftests/bpf: fix "metadata marker" getting overwritten by the
    netstack

 net/bpf/test_run.c                                   | 12 +++++++++++-
 .../selftests/bpf/prog_tests/xdp_do_redirect.c       |  7 ++++---
 .../selftests/bpf/progs/test_xdp_do_redirect.c       |  2 +-
 3 files changed, 16 insertions(+), 5 deletions(-)

-- 
2.39.2