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From: Azeem Shaikh <azeemshaikh38@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>
Cc: linux-hardening@vger.kernel.org,
	Azeem Shaikh <azeemshaikh38@gmail.com>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
	Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH] bpf: Replace all non-returning strlcpy with strscpy
Date: Tue, 30 May 2023 15:56:59 +0000	[thread overview]
Message-ID: <20230530155659.309657-1-azeemshaikh38@gmail.com> (raw)

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().
No return values were used, so direct replacement is safe.

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
---
 kernel/bpf/preload/bpf_preload_kern.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/bpf/preload/bpf_preload_kern.c b/kernel/bpf/preload/bpf_preload_kern.c
index b56f9f3314fd..0c63bc2cd895 100644
--- a/kernel/bpf/preload/bpf_preload_kern.c
+++ b/kernel/bpf/preload/bpf_preload_kern.c
@@ -23,9 +23,9 @@ static void free_links_and_skel(void)
 
 static int preload(struct bpf_preload_info *obj)
 {
-	strlcpy(obj[0].link_name, "maps.debug", sizeof(obj[0].link_name));
+	strscpy(obj[0].link_name, "maps.debug", sizeof(obj[0].link_name));
 	obj[0].link = maps_link;
-	strlcpy(obj[1].link_name, "progs.debug", sizeof(obj[1].link_name));
+	strscpy(obj[1].link_name, "progs.debug", sizeof(obj[1].link_name));
 	obj[1].link = progs_link;
 	return 0;
 }


             reply	other threads:[~2023-05-30 15:57 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-30 15:56 Azeem Shaikh [this message]
2023-05-30 23:17 ` [PATCH] bpf: Replace all non-returning strlcpy with strscpy Kees Cook
2023-05-31 11:10 ` patchwork-bot+netdevbpf

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