From: Kees Cook <kees@kernel.org>
To: Andrii Nakryiko <andrii@kernel.org>
Cc: Eduard Zingerman <eddyz87@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>,
bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-hardening@vger.kernel.org
Subject: Re: [PATCH] libbpf: Replace strncpy() with strnlen()+memcpy() in skel_map_create()
Date: Mon, 23 Mar 2026 22:25:50 -0700 [thread overview]
Message-ID: <202603232224.C1555BF@keescook> (raw)
In-Reply-To: <20260324040535.work.851-kees@kernel.org>
On Mon, Mar 23, 2026 at 09:05:39PM -0700, Kees Cook wrote:
> While the original strncpy() would have copied a full 16 bytes from an
> overlong name (producing an unterminated field that the syscall rejects),
> but this wasn't a reachable state. This replacement will instead always
> truncate to 15 bytes and keeps the NUL terminator, which should have no
> behavioral changes with the present code and avoids potential issues
> with future over-long string literals.
Hm, I got a failure report, but it *seems* unrelated? But nothing else
fails that way recently, so I will try a v2 with the "unterminated at 16
bytes" behavior restored and see if it passes...
test_progs_no_alu32-x86_64-llvm-21:
https://github.com/kernel-patches/bpf/actions/runs/23472955268/job/68300440546
--
Kees Cook
next prev parent reply other threads:[~2026-03-24 5:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-24 4:05 [PATCH] libbpf: Replace strncpy() with strnlen()+memcpy() in skel_map_create() Kees Cook
2026-03-24 5:25 ` Kees Cook [this message]
2026-03-24 14:40 ` sun jian
2026-03-24 14:42 ` Alexei Starovoitov
2026-03-24 15:28 ` Kees Cook
2026-03-24 15:38 ` Alexei Starovoitov
2026-03-24 16:23 ` Kees Cook
2026-03-24 16:31 ` Alexei Starovoitov
2026-03-25 4:10 ` Kees Cook
2026-03-25 15:48 ` Alexei Starovoitov
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