linux-kernel - [PATCH v2 bpf 0/2] bpf: skip non exist keys in

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]

Message-ID: <cover.1738905497.git.yan@cloudflare.com>
Date: Thu, 6 Feb 2025 21:45:11 -0800
From: Yan Zhai <yan@...udflare.com>
To: bpf@...r.kernel.org
Cc: Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	John Fastabend <john.fastabend@...il.com>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>,
	Yonghong Song <yonghong.song@...ux.dev>,
	KP Singh <kpsingh@...nel.org>, Stanislav Fomichev <sdf@...ichev.me>,
	Hao Luo <haoluo@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
	Mykola Lysenko <mykolal@...com>, Shuah Khan <shuah@...nel.org>,
	Yan Zhai <yan@...udflare.com>, Brian Vazquez <brianvv@...gle.com>,
	linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
	kernel-team@...udflare.com, Hou Tao <houtao@...weicloud.com>
Subject: [PATCH v2 bpf 0/2] bpf: skip non exist keys in

generic_map_lookup_batch

The generic_map_lookup_batch currently returns EINTR if it fails with
ENOENT and retries several times on bpf_map_copy_value. The next batch
would start from the same location, presuming it's a transient issue.
This is incorrect if a map can actually have "holes", i.e.
"get_next_key" can return a key that does not point to a valid value. At
least the array of maps type may contain such holes legitly. Right now
these holes show up, generic batch lookup cannot proceed any more. It
will always fail with EINTR errors.

This patch fixes this behavior by skipping the non-existing key, and
does not return EINTR any more.

V1->V2: split the fix and selftests; fixed a few selftests issues.

V1: https://lore.kernel.org/bpf/Z6OYbS4WqQnmzi2z@debian.debian/

Yan Zhai (2):
  bpf: skip non exist keys in generic_map_lookup_batch
  selftests: bpf: test batch lookup on array of maps with holes

 kernel/bpf/syscall.c                          | 16 ++---
 .../bpf/map_tests/map_in_map_batch_ops.c      | 62 +++++++++++++------
 2 files changed, 49 insertions(+), 29 deletions(-)

-- 
2.39.5