From nobody Sat Nov 23 11:48:30 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 20C29205E13; Wed, 13 Nov 2024 18:47:07 +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=1731523628; cv=none; b=VT/BSaYszIL0OTJnsV76mdCnewk97t0ldic8FfqFab7hXe+OOYotGirNUmktc1g+fSoyzeyAVwkEVfpu9u7m1omOuqLMca4el1a1MYTUdl5aVmc6BQUwPzyZlmTN11KnD3NEAadBcTb3xSjLdKNuA6rbS8t9YJo+NaDEfXmy4Q0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731523628; c=relaxed/simple; bh=PTBVL2tPmPN6P0/h38z8Y2oc6jqzgBOjiS1aI01AKeM=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=GjnSGe2TjDQKh483R+0zVaoS6uzBNpH1ODiZC2Za65TKQdNSMQGmakE22ZMnAGTSgoMEAdpVjGaOd4nTwDI9xPq0UcR950RpVg61hnM8G64x7z8+J7PJOPdmw3OnukHy5FXbsWdHd96ER81iSp60Dju5hSL+gTptW0vG/Tkl6UY= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OsDYDsVz; 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="OsDYDsVz" Received: by smtp.kernel.org (Postfix) with ESMTPS id A568AC4CECF; Wed, 13 Nov 2024 18:47:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731523627; bh=PTBVL2tPmPN6P0/h38z8Y2oc6jqzgBOjiS1aI01AKeM=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=OsDYDsVzVrPdBnUG4IQpFYZQEfL4QclBGBwUONlLvNjmgLm6V+TloGIoYEPHwGTy0 tkz2UBdyvu5BSOFaDGNHBlcQlF8nkB2CxI5//IzdiIi+BRrWoV283k/Lp6z6Qf3VsV mcHknwgGXH2Rh2Yqwo6luktMRKJAj4k0Os7lMeDCcQjwk6rpHL4F29CW0QwVzoHypk TgPVn2L/ZCtJ/OqrcGQNvakEp3QxK3Zql4Rei1gEvIT18FSAOBrS4sJk6vPqCNq17Q NrUICRLOaXYgyMQVtNMDbTQo7kWl8Ij/KjXUERNp4y0+7OIag0cVD+4Io6e2ihebWK R7kxEBpb23DkA== 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 91040D637A9; Wed, 13 Nov 2024 18:47:07 +0000 (UTC) From: Dmitry Safonov via B4 Relay Date: Wed, 13 Nov 2024 18:46:41 +0000 Subject: [PATCH net v2 2/5] net/diag: Warn only once on EMSGSIZE Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241113-tcp-md5-diag-prep-v2-2-00a2a7feb1fa@gmail.com> References: <20241113-tcp-md5-diag-prep-v2-0-00a2a7feb1fa@gmail.com> In-Reply-To: <20241113-tcp-md5-diag-prep-v2-0-00a2a7feb1fa@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 , Davide Caratti , Kuniyuki Iwashima 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=1731523626; l=1040; i=0x7f454c46@gmail.com; s=20240410; h=from:subject:message-id; bh=yIywEl4vHF1DrEzww1U5WkkGaZ14BAMY3GjreNIr5EA=; b=ahphbF5AdQ/YmMPb55wCdyrbqn/6GMhNcA7jAD8XjpApgUgjhWRAjpue/f/P1DrnN2kU89FZ+ GTRYqJkq0hjDMElCMf254wHTm+cB5av1JauVhNtee+mxdyHaF/mjKwV 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