netdev - [PATCH bpf v2 0/4] bpf, sockmap: Fix infinite recursion in sock_map

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Date:   Sat, 21 Jan 2023 13:41:42 +0100
From:   Jakub Sitnicki <jakub@...udflare.com>
To:     bpf@...r.kernel.org
Cc:     netdev@...r.kernel.org, John Fastabend <john.fastabend@...il.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Alexei Starovoitov <ast@...nel.org>,
        Andrii Nakryiko <andrii@...nel.org>,
        kernel-team@...udflare.com,
        syzbot+04c21ed96d861dccc5cd@...kaller.appspotmail.com
Subject: [PATCH bpf v2 0/4] bpf, sockmap: Fix infinite recursion in
 sock_map_close

This patch set addresses the syzbot report in [1].

Patch #1 has been suggested by Eric [2]. I extended it to cover the rest of
sock_map proto callbacks. Otherwise we would still overflow the stack.

Patch #2 contains the actual fix and bug analysis.
Patches #3 & #4 add coverage to selftests to trigger the bug.

[1] https://lore.kernel.org/all/00000000000073b14905ef2e7401@google.com/
[2] https://lore.kernel.org/all/CANn89iK2UN1FmdUcH12fv_xiZkv2G+Nskvmq7fG6aA_6VKRf6g@mail.gmail.com/

---
v1 -> v2:
v1: https://lore.kernel.org/r/20230113-sockmap-fix-v1-0-d3cad092ee10@cloudflare.com
[v1 didn't hit bpf@ ML by mistake]

 * pull in Eric's patch to protect against recursion loop bugs (Eric)
 * add a macro helper to check if pointer is inside a memory range (Eric)

---
Jakub Sitnicki (4):
      bpf, sockmap: Don't let sock_map_{close,destroy,unhash} call itself
      bpf, sockmap: Check for any of tcp_bpf_prots when cloning a listener
      selftests/bpf: Pass BPF skeleton to sockmap_listen ops tests
      selftests/bpf: Cover listener cloning with progs attached to sockmap

 include/linux/util_macros.h                        | 12 ++++
 net/core/sock_map.c                                | 61 ++++++++--------
 net/ipv4/tcp_bpf.c                                 |  4 +-
 .../selftests/bpf/prog_tests/sockmap_listen.c      | 81 +++++++++++++++++-----
 4 files changed, 111 insertions(+), 47 deletions(-)