Tze-nan Wu f8d6acb19f bpf, net: Fix a potential race in do_sock_getsockopt()
[ Upstream commit 33f339a1ba54e56bba57ee9a77c71e385ab4825c ]

There's a potential race when `cgroup_bpf_enabled(CGROUP_GETSOCKOPT)` is
false during the execution of `BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN`, but
becomes true when `BPF_CGROUP_RUN_PROG_GETSOCKOPT` is called.
This inconsistency can lead to `BPF_CGROUP_RUN_PROG_GETSOCKOPT` receiving
an "-EFAULT" from `__cgroup_bpf_run_filter_getsockopt(max_optlen=0)`.
Scenario shown as below:

           `process A`                      `process B`
           -----------                      ------------
  BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN
                                            enable CGROUP_GETSOCKOPT
  BPF_CGROUP_RUN_PROG_GETSOCKOPT (-EFAULT)

To resolve this, remove the `BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN` macro and
directly uses `copy_from_sockptr` to ensure that `max_optlen` is always
set before `BPF_CGROUP_RUN_PROG_GETSOCKOPT` is invoked.

Fixes: 0d01da6afc ("bpf: implement getsockopt and setsockopt hooks")
Co-developed-by: Yanghui Li <yanghui.li@mediatek.com>
Signed-off-by: Yanghui Li <yanghui.li@mediatek.com>
Co-developed-by: Cheng-Jui Wang <cheng-jui.wang@mediatek.com>
Signed-off-by: Cheng-Jui Wang <cheng-jui.wang@mediatek.com>
Signed-off-by: Tze-nan Wu <Tze-nan.Wu@mediatek.com>
Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://patch.msgid.link/20240830082518.23243-1-Tze-nan.Wu@mediatek.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-12 11:11:34 +02:00
2024-09-12 11:11:27 +02:00
2022-09-28 09:02:20 +02:00
2024-09-08 07:54:49 +02:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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