From nobody Sun Nov 24 09:18:59 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CA735208219; Wed, 6 Nov 2024 18:49:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730918995; cv=none; b=VwY3l8KEWMo08CO8B40bfPMA/aKwmDg8MzREV2mffjyT4r1U8SrXINnMIvfQiueO6DGw4cdCKukPmwbZsCUk5HZq9672ulskzmo/iIgTOM2zFC7E+lk73rTOvQGa+labbDxogxqbFIDCft3AB275qDqq8uLeUdfyVD2Tlud5LQQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730918995; c=relaxed/simple; bh=PTBVL2tPmPN6P0/h38z8Y2oc6jqzgBOjiS1aI01AKeM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=MhgQwbLvrOVfrmS/wQLP2K+tGvEDEFeWTWuCcOBGHuGjiCFkSc78Pno3ZG7MoafQJNW4RD8DfrCPvv0rfSNVE9uQT49H6uu89US+6EbxgGcuLLfFDEdW/hn97TECH4MANM3ggfhTNTVIwsmXSpNGK80d1rrgtQODrMbmWH4Pl/c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IUCgvukC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IUCgvukC" Received: by smtp.kernel.org (Postfix) with ESMTPS id 7CE1CC4CECD; Wed, 6 Nov 2024 18:49:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730918995; bh=PTBVL2tPmPN6P0/h38z8Y2oc6jqzgBOjiS1aI01AKeM=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=IUCgvukCE2xslOF/m4R+aX/b1Mo4ERsVCh22l19vBv/Pv1OUXioO/sJf33MH4ApjH kETYe1FfmJMKGCzG5J9Mu4Pb1zLlEAM6WvtYe7FP/yldtARcgjz/AHMxB9Rn4HKBzC miOFydWNx7l5xqv9xCsBUln6yFKeRmC/haMKodW54jwiomzNYV/BWg0BDldXXseX+g zPg3qg6LYFVrI54ZhhuQF/gUEZL9FfRLeue7gCn2RCKoL9BEisoKhPhX22qgDV7o/h h2+MTjTFyF+kl79lEtLq5OrlMTF6RDftRYaeWgIkYCX9xaA9iR8e0Bdl/LsqOvIvdG fszOAv0aWMTVg== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6C268D59F65; Wed, 6 Nov 2024 18:49:55 +0000 (UTC) From: Dmitry Safonov via B4 Relay Date: Wed, 06 Nov 2024 18:10:15 +0000 Subject: [PATCH net 2/6] net/diag: Warn only once on EMSGSIZE Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241106-tcp-md5-diag-prep-v1-2-d62debf3dded@gmail.com> References: <20241106-tcp-md5-diag-prep-v1-0-d62debf3dded@gmail.com> In-Reply-To: <20241106-tcp-md5-diag-prep-v1-0-d62debf3dded@gmail.com> To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , David Ahern , Ivan Delalande , Matthieu Baerts , Mat Martineau , Geliang Tang , Boris Pismenny , John Fastabend Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, mptcp@lists.linux.dev, Dmitry Safonov <0x7f454c46@gmail.com> X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=ed25519-sha256; t=1730918993; l=1040; i=0x7f454c46@gmail.com; s=20240410; h=from:subject:message-id; bh=yIywEl4vHF1DrEzww1U5WkkGaZ14BAMY3GjreNIr5EA=; b=bEe3Nj9Ft2qwDiKOg6KHN8UOZdyHHL7bHoshX5SjL0EAZKvZYSRS+mbNynLT6KyczIi/0eUzz 85bYlJhVu7LDv+U41rm8yFwML1IPrO7jppiwuqrOGVdv3zmyeZetppD X-Developer-Key: i=0x7f454c46@gmail.com; a=ed25519; pk=cFSWovqtkx0HrT5O9jFCEC/Cef4DY8a2FPeqP4THeZQ= X-Endpoint-Received: by B4 Relay for 0x7f454c46@gmail.com/20240410 with auth_id=152 X-Original-From: Dmitry Safonov <0x7f454c46@gmail.com> Reply-To: 0x7f454c46@gmail.com From: Dmitry Safonov <0x7f454c46@gmail.com> The code clearly expects that the pre-allocated skb will be enough for the netlink reply message. But if in an unbelievable situation there is a kernel issue and sk_diag_fill() fails with -EMSGSIZE, this WARN_ON() can be triggered from userspace. That aggravates the issue from KASLR leak into possible DOS vector. Use WARN_ON_ONCE() which is clearly enough to provide an information on a kernel issue. Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> --- net/ipv4/inet_diag.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c index 67b9cc4c0e47a596a4d588e793b7f13ee040a1e3..ca9a7e61d8d7de80cb234c45c41= d6357fde50c11 100644 --- a/net/ipv4/inet_diag.c +++ b/net/ipv4/inet_diag.c @@ -583,7 +583,7 @@ int inet_diag_dump_one_icsk(struct inet_hashinfo *hashi= nfo, =20 err =3D sk_diag_fill(sk, rep, cb, req, 0, net_admin); if (err < 0) { - WARN_ON(err =3D=3D -EMSGSIZE); + WARN_ON_ONCE(err =3D=3D -EMSGSIZE); nlmsg_free(rep); goto out; } --=20 2.42.2