From nobody Sun Sep 22 13:34:04 2024 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 75741C433EF for ; Tue, 30 Nov 2021 10:14:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230355AbhK3KRo (ORCPT ); Tue, 30 Nov 2021 05:17:44 -0500 Received: from mta-p8.oit.umn.edu ([134.84.196.208]:37684 "EHLO mta-p8.oit.umn.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229729AbhK3KRn (ORCPT ); Tue, 30 Nov 2021 05:17:43 -0500 Received: from localhost (unknown [127.0.0.1]) by mta-p8.oit.umn.edu (Postfix) with ESMTP id 4J3J3g5YLWz9vBt2 for ; Tue, 30 Nov 2021 10:14:23 +0000 (UTC) X-Virus-Scanned: amavisd-new at umn.edu Received: from mta-p8.oit.umn.edu ([127.0.0.1]) by localhost (mta-p8.oit.umn.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 92V0S6M5oSDf for ; Tue, 30 Nov 2021 04:14:23 -0600 (CST) Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mta-p8.oit.umn.edu (Postfix) with ESMTPS id 4J3J3g3Tpwz9vBtK for ; Tue, 30 Nov 2021 04:14:23 -0600 (CST) DMARC-Filter: OpenDMARC Filter v1.3.2 mta-p8.oit.umn.edu 4J3J3g3Tpwz9vBtK DKIM-Filter: OpenDKIM Filter v2.11.0 mta-p8.oit.umn.edu 4J3J3g3Tpwz9vBtK Received: by mail-pf1-f197.google.com with SMTP id q2-20020a056a00084200b004a2582fcec1so12588608pfk.15 for ; Tue, 30 Nov 2021 02:14:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=umn.edu; s=google; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=ezPDMyg4z6FUtdCtlSvrXZjWSKm8o+6pNXDt3YFkKII=; b=Q54MRiSiawsPKrbhwo2sZaqpTRa/egZ01MFGeAUM/DZ82+sJerdvNIHnksW6nM/pta QVvvv3AOILqpqIUGAsZnGjhDuZUxY8mAyX0zTIx80kN8PEb9AEsRK5jJGHWUMLXq/+9p 18FLISF6m1jmgoMj7A59ud8iJTJv5unr1HFInzCEsKS+QB+t/YR4V3rzZ1LvapFYGkbM QXfePCn+j3l7xY4BDmkJJY2XL+0JaBjQlw6vW+JCLzuLiPZgyoEb13RWjnpJptvj6N8Z a8f7HWlh5y7VeizpsvQbTZpU78wh84cs8PkNO9HlyMA53OgdVR/HBwqSynVvwZI04iP4 0joA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=ezPDMyg4z6FUtdCtlSvrXZjWSKm8o+6pNXDt3YFkKII=; b=cOAYtZ8MBpji59kAyLU0xz2jfOLAwTTF1bvKtuh5AAveVLFoj3aZe86gL3ZyJgJl8d hhWC2B0OyFFz7t0fBhCw5cr8aQkPgl3e3Xb7AcrxtmAbWZE6211CwkVitpZB2RjNO5Dd A3CAB+8QYkpTWdgb5fsX2vR848CncnSAf5eHjAUsMxiBDQxbZsm0oezGa4Xq83vcdqii hqKutprUEXsjqglUIvUiXi6qT+wNU5BT5XYfgPHGT2K9vrypLkBwmvuR3RSk4Ua4tbMc /EbLP1t9kMcIOsMQlOGrXI1gp8VrfwchYDjArxmVAj5BdSuDsE6DthkNBdiaQbdYSmp0 8tqQ== X-Gm-Message-State: AOAM530aY/8wucIg02+A0YKR3ASqSJdmvpzUwjeupF79GeMAXIsIut1K HBMJRtAFG/Auo3HzXGKyushoI8cgLRl+vQZvrvjL9hwsqxCpcBaTKwR88xQ1Ii02MJ+8juXHAIA TnKTdDiDrtnqrDEi1jqUEd2wrHxHj X-Received: by 2002:a17:902:ce8c:b0:141:d218:954 with SMTP id f12-20020a170902ce8c00b00141d2180954mr66086313plg.1.1638267262768; Tue, 30 Nov 2021 02:14:22 -0800 (PST) X-Google-Smtp-Source: ABdhPJwZhxN9ocyihGfNCGLMaz0RjGDMqMGBOZyUXuyOBDhzdCoh/2u3iNSfs04TgQLOMNklWxKYFw== X-Received: by 2002:a17:902:ce8c:b0:141:d218:954 with SMTP id f12-20020a170902ce8c00b00141d2180954mr66086293plg.1.1638267262561; Tue, 30 Nov 2021 02:14:22 -0800 (PST) Received: from zqy787-GE5S.lan ([36.7.42.137]) by smtp.gmail.com with ESMTPSA id t23sm12504231pgo.35.2021.11.30.02.14.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Nov 2021 02:14:22 -0800 (PST) From: Zhou Qingyang To: zhou1615@umn.edu Cc: kjlu@umn.edu, Michael Turquette , Stephen Boyd , Matthias Brugger , Nicolas Boichat , Weiyi Lu , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] clk: mediatek: mt8183: Fix a NULL pointer dereference in clk_mt8183_apmixed_probe() Date: Tue, 30 Nov 2021 18:14:14 +0800 Message-Id: <20211130101416.102608-1-zhou1615@umn.edu> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" In clk_mt8183_apmixed_probe(), the return value of mtk_alloc_clk_data() is assigned to clk_data and used in mtk_clk_register_plls(). There is a dereference of clk_data in mtk_clk_register_plls(), which could lead to a NULL pointer dereference on failure of mtk_alloc_clk_data(). Fix this bug by adding a check of clk_data. Another way to fix this bug is to add a check of clk_data in mtk_clk_register_plls(), which may solve many similar bugs but could cause potential problems to previously correct cases as the API is changed. This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug. Builds with CONFIG_COMMON_CLK_MT8183=3Dy show no new warnings, and our static analyzer no longer warns about this code. Fixes: acddfc2c261b ("clk: mediatek: Add MT8183 clock support") Signed-off-by: Zhou Qingyang --- drivers/clk/mediatek/clk-mt8183.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/clk/mediatek/clk-mt8183.c b/drivers/clk/mediatek/clk-m= t8183.c index 5046852eb0fd..9eca62186ec5 100644 --- a/drivers/clk/mediatek/clk-mt8183.c +++ b/drivers/clk/mediatek/clk-mt8183.c @@ -1158,6 +1158,8 @@ static int clk_mt8183_apmixed_probe(struct platform_d= evice *pdev) struct device_node *node =3D pdev->dev.of_node; =20 clk_data =3D mtk_alloc_clk_data(CLK_APMIXED_NR_CLK); + if (!clk_data) + return -ENOMEM; =20 mtk_clk_register_plls(node, plls, ARRAY_SIZE(plls), clk_data); =20 --=20 2.25.1