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From: Azeem Shaikh <azeemshaikh38@gmail.com>
To: Jamal Hadi Salim <jhs@mojatatu.com>,
	Cong Wang <xiyou.wangcong@gmail.com>,
	Jiri Pirko <jiri@resnulli.us>
Cc: linux-hardening@vger.kernel.org,
	Azeem Shaikh <azeemshaikh38@gmail.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Subject: [PATCH] net: sched: Replace strlcpy with strscpy
Date: Mon, 10 Jul 2023 03:07:11 +0000	[thread overview]
Message-ID: <20230710030711.812898-1-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().

Direct replacement is safe here since return value of -errno
is used to check for truncation instead of sizeof(dest).

[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>
---
 net/sched/act_api.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index f7887f42d542..9d3f26bf0440 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -1320,7 +1320,7 @@ struct tc_action_ops *tc_action_load_ops(struct nlattr *nla, bool police,
 			return ERR_PTR(err);
 		}
 	} else {
-		if (strlcpy(act_name, "police", IFNAMSIZ) >= IFNAMSIZ) {
+		if (strscpy(act_name, "police", IFNAMSIZ) < 0) {
 			NL_SET_ERR_MSG(extack, "TC action name too long");
 			return ERR_PTR(-EINVAL);
 		}
-- 
2.41.0.255.g8b1d071c50-goog



             reply	other threads:[~2023-07-10  3:07 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-10  3:07 Azeem Shaikh [this message]
2023-07-10  4:26 ` [PATCH] net: sched: Replace strlcpy with strscpy Pavan Chebbi
2023-07-10  7:30 ` patchwork-bot+netdevbpf

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