From patchwork Thu Mar 23 10:37:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Ahmad Fatoum X-Patchwork-Id: 13185485 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6CB78C6FD1C for ; Thu, 23 Mar 2023 10:41:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230291AbjCWKk6 (ORCPT ); Thu, 23 Mar 2023 06:40:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230283AbjCWKkf (ORCPT ); Thu, 23 Mar 2023 06:40:35 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F1A01E1EE for ; Thu, 23 Mar 2023 03:37:49 -0700 (PDT) Received: from drehscheibe.grey.stw.pengutronix.de ([2a0a:edc0:0:c01:1d::a2]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pfIKD-0006Dh-SD; Thu, 23 Mar 2023 11:37:41 +0100 Received: from [2a0a:edc0:0:1101:1d::54] (helo=dude05.red.stw.pengutronix.de) by drehscheibe.grey.stw.pengutronix.de with esmtp (Exim 4.94.2) (envelope-from ) id 1pfIKB-00680F-3n; Thu, 23 Mar 2023 11:37:39 +0100 Received: from afa by dude05.red.stw.pengutronix.de with local (Exim 4.94.2) (envelope-from ) id 1pfIK9-009wtp-V6; Thu, 23 Mar 2023 11:37:37 +0100 From: Ahmad Fatoum To: Linus Walleij , =?utf-8?q?Alvin_=C5=A0ipraga?= , Andrew Lunn , Florian Fainelli , Vladimir Oltean , Luiz Angelo Daros de Luca , "David S. Miller" Cc: kernel@pengutronix.de, Ahmad Fatoum , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net v2] net: dsa: realtek: fix out-of-bounds access Date: Thu, 23 Mar 2023 11:37:35 +0100 Message-Id: <20230323103735.2331786-1-a.fatoum@pengutronix.de> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:c01:1d::a2 X-SA-Exim-Mail-From: afa@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: netdev@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org The probe function sets priv->chip_data to (void *)priv + sizeof(*priv) with the expectation that priv has enough trailing space. However, only realtek-smi actually allocated this chip_data space. Do likewise in realtek-mdio to fix out-of-bounds accesses. These accesses likely went unnoticed so far, because of an (unused) buf[4096] member in struct realtek_priv, which caused kmalloc to round up the allocated buffer to a big enough size, so nothing of value was overwritten. With a different allocator (like in the barebox bootloader port of the driver) or with KASAN, the memory corruption becomes quickly apparent. Fixes: aac94001067d ("net: dsa: realtek: add new mdio interface for drivers") Reviewed-by: Florian Fainelli Reviewed-by: Luiz Angelo Daros de Luca Reviewed-by: Alvin Šipraga Reviewed-by: Linus Walleij Signed-off-by: Ahmad Fatoum --- v1 -> v2: - drop v1's patch 2/2, which appears to have no functional effect (Jakub) - extend commit message with probable reason why this long standing bug did not pop up so far in Linux (Prompted by Linus' question) - use saturating size_add instead of wrap-around addition (Jakub) - added reviewer R-b's --- drivers/net/dsa/realtek/realtek-mdio.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/dsa/realtek/realtek-mdio.c b/drivers/net/dsa/realtek/realtek-mdio.c index 7134886fe78d..1691faf77f00 100644 --- a/drivers/net/dsa/realtek/realtek-mdio.c +++ b/drivers/net/dsa/realtek/realtek-mdio.c @@ -21,6 +21,7 @@ #include #include +#include #include #include "realtek.h" @@ -152,7 +153,9 @@ static int realtek_mdio_probe(struct mdio_device *mdiodev) if (!var) return -EINVAL; - priv = devm_kzalloc(&mdiodev->dev, sizeof(*priv), GFP_KERNEL); + priv = devm_kzalloc(&mdiodev->dev, + size_add(sizeof(*priv), var->chip_data_sz), + GFP_KERNEL); if (!priv) return -ENOMEM;