netdev - [PATCH v3 bpf 0/2] bpf: return proper error codes for lwt redirect

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-next>] [day] [month] [year] [list]

Date: Mon, 24 Jul 2023 21:12:12 -0700
From: Yan Zhai <yan@...udflare.com>
To: bpf@...r.kernel.org
Cc: Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>, Song Liu <song@...nel.org>,
	Yonghong Song <yhs@...com>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...gle.com>,
	Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
	Mykola Lysenko <mykolal@...com>, Shuah Khan <shuah@...nel.org>,
	Yan Zhai <yan@...udflare.com>, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org, linux-kselftest@...r.kernel.org,
	kernel-team@...udflare.com, Jordan Griege <jgriege@...udflare.com>
Subject: [PATCH v3 bpf 0/2] bpf: return proper error codes for lwt redirect

lwt xmit hook does not expect positive return values in function
ip_finish_output2 and ip6_finish_output2. However, BPF redirect programs
can return positive values such like NET_XMIT_DROP, NET_RX_DROP, and etc
as errors. Such return values can panic the kernel unexpectedly:

https://gist.github.com/zhaiyan920/8fbac245b261fe316a7ef04c9b1eba48

This patch fixes the return values from BPF redirect, so the error
handling would be consistent at xmit hook. It also adds a few test cases
to prevent future regressions.

v2: https://lore.kernel.org/netdev/ZLdY6JkWRccunvu0@debian.debian/ 
v1: https://lore.kernel.org/bpf/ZLbYdpWC8zt9EJtq@debian.debian/

changes since v2:
  * subject name changed
  * also covered redirect to ingress case
  * added selftests

changes since v1:
  * minor code style changes

Yan Zhai (2):
  bpf: fix skb_do_redirect return values
  bpf: selftests: add lwt redirect regression test cases

 net/core/filter.c                             |  12 +-
 tools/testing/selftests/bpf/Makefile          |   1 +
 .../selftests/bpf/progs/test_lwt_redirect.c   |  67 +++++++
 .../selftests/bpf/test_lwt_redirect.sh        | 165 ++++++++++++++++++
 4 files changed, 244 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/progs/test_lwt_redirect.c
 create mode 100755 tools/testing/selftests/bpf/test_lwt_redirect.sh

-- 
2.30.2