From nobody Sun Sep 22 13:26:37 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 23D18C433F5 for ; Tue, 30 Nov 2021 09:58:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240421AbhK3KBT (ORCPT ); Tue, 30 Nov 2021 05:01:19 -0500 Received: from mta-p8.oit.umn.edu ([134.84.196.208]:59596 "EHLO mta-p8.oit.umn.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235604AbhK3KBS (ORCPT ); Tue, 30 Nov 2021 05:01:18 -0500 Received: from localhost (unknown [127.0.0.1]) by mta-p8.oit.umn.edu (Postfix) with ESMTP id 4J3Hhk6tMFz9vBtN for ; Tue, 30 Nov 2021 09:57:58 +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 c2f2YpSEHHB5 for ; Tue, 30 Nov 2021 03:57:58 -0600 (CST) Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) (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 4J3Hhk4lxwz9vBt2 for ; Tue, 30 Nov 2021 03:57:58 -0600 (CST) DMARC-Filter: OpenDMARC Filter v1.3.2 mta-p8.oit.umn.edu 4J3Hhk4lxwz9vBt2 DKIM-Filter: OpenDKIM Filter v2.11.0 mta-p8.oit.umn.edu 4J3Hhk4lxwz9vBt2 Received: by mail-pf1-f200.google.com with SMTP id w2-20020a627b02000000b0049fa951281fso12562873pfc.9 for ; Tue, 30 Nov 2021 01:57:58 -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=MrDmOmqy53ncuiVE/GEYR1H1+QCkQb8baxwPMZ1tiko=; b=bzUs68d9T5urMxTKmIOyZFIVWQNM0enC8qVpTkeU6GGTbxGaHO2Y1eA5KwwMlg1hIY ONUFYNTTmKTp9uHx5zb99/5WZ95Yzw5z7wu2l5XyLEN/VRZdqobUvl/dpns5/+6LQZZf M2xUwQqyQTo3lhQBYvnss4YCuOvNsXDCU+JQQOtATxaJFClmqt8/M+wSddCu8UwRTLln N2DtnIEEPPQXjU6lLHh4mFhZLs+oD4pgmwCrSpmkethS51Xatkm/lh8Y+wnZCamQ5TCz xGTEE01kGoxa4T0ArRKugyOAnek/W1htiYzUpSM4cum6LW1W3wyLFYHxtVuihnsBMmid 0scA== 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=MrDmOmqy53ncuiVE/GEYR1H1+QCkQb8baxwPMZ1tiko=; b=q6im+boqkVCxBtErXtHQhb8SD3q6jKDcKvU2A19/zkOZoHh84xFBPOHYjTrUU3yNro MukVM/u4Nz8SOQNLIHn15EsyEOqalvSe/f5lWvOXzps2GJKL5ZfGsfunUVAhLSO0ZLEe /9+WAvFYdJpoIjg4JdtDCVQ/YWi6NQojYEeNZSMT7nE5pRiyK4a1eG1wkkl75Bw8eDqy PVXyumz1RZtJpgNr/vfZs1mzo5D4FaZbJVTt3HoqEGt0CBTlaA0zObwcZp8xBi3M7xpG I7PXFFoxs37qh+vRdXErrMf3OvVoXIqv/Mslwj086zi0FGGh4NdqxfziXI6RaZ73ovlB IL0Q== X-Gm-Message-State: AOAM533c8n/IH4pwPA0FrhsPB0S8jUTp6EZg0RpnjVZtY+gkXjXJnwUw ur2j17K5lwSGZcAwIdi+FY/DKO8U/fvro3DrOMh7CaR9fq+XIzXgSP5RHeVf9AjVCdj7q6S58Is vI+38E6xosSA+CmnrCUUClbHk5MvO X-Received: by 2002:aa7:864f:0:b0:4a2:ea0a:a16d with SMTP id a15-20020aa7864f000000b004a2ea0aa16dmr45599380pfo.11.1638266277959; Tue, 30 Nov 2021 01:57:57 -0800 (PST) X-Google-Smtp-Source: ABdhPJyz0S5KZw1PVwUuiwDkP9/RaONTERv32EcCQUY7AvGGsmbqzODVGFX2Awn3Qo0pkVauxwXzKQ== X-Received: by 2002:aa7:864f:0:b0:4a2:ea0a:a16d with SMTP id a15-20020aa7864f000000b004a2ea0aa16dmr45599362pfo.11.1638266277757; Tue, 30 Nov 2021 01:57:57 -0800 (PST) Received: from zqy787-GE5S.lan ([36.7.42.137]) by smtp.gmail.com with ESMTPSA id v3sm7229121pga.78.2021.11.30.01.57.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Nov 2021 01:57:57 -0800 (PST) From: Zhou Qingyang To: zhou1615@umn.edu Cc: kjlu@umn.edu, Michael Turquette , Stephen Boyd , Matthias Brugger , Fabien Parent , 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: mt8167: Fix a NULL pointer dereference in mtk_apmixedsys_init() Date: Tue, 30 Nov 2021 17:57:50 +0800 Message-Id: <20211130095752.98821-1-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 mtk_apmixedsys_init(), 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_MT8167=3Dy show no new warnings, and our static analyzer no longer warns about this code. Fixes: a68224832118 ("clk: mediatek: Add MT8167 clock support") Signed-off-by: Zhou Qingyang --- drivers/clk/mediatek/clk-mt8167.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/clk/mediatek/clk-mt8167.c b/drivers/clk/mediatek/clk-m= t8167.c index e5ea10e31799..7b18b751487f 100644 --- a/drivers/clk/mediatek/clk-mt8167.c +++ b/drivers/clk/mediatek/clk-mt8167.c @@ -1047,6 +1047,11 @@ static void __init mtk_apmixedsys_init(struct device= _node *node) } =20 clk_data =3D mtk_alloc_clk_data(MT8167_CLK_APMIXED_NR_CLK); + if (!clk_data) { + pr_err("%s(): could not register clock provider: %d\n", + __func__, -ENOMEM); + return; + } =20 mtk_clk_register_plls(node, plls, ARRAY_SIZE(plls), clk_data); mtk_clk_register_dividers(apmixed_adj_divs, ARRAY_SIZE(apmixed_adj_divs), --=20 2.25.1