From patchwork Thu Nov 14 22:49:21 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 13875719 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 D1BF618B464; Thu, 14 Nov 2024 22:49:25 +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=1731624567; cv=none; b=AgtuL1xZy1flucbDvo+YRyH8FQ8XMjiJnbJoPDspqh6xpiiBUaxB2j5FWIhmJ/79PgCyTX87x+6K2El3VqU4hzG9HOSSd3ILq4iFFRz+L8P/vSrAGNo7wiyjVOvEmEm+mw4xgjuXwDCW9Zm4tuTmWsdTMK6OUZCq+J39igwGyDY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731624567; c=relaxed/simple; bh=lACSCrdzRLG5x1E+njLfHcgssYzowjsw+9YGqqUEk5I=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition; b=JlyYFZNZfFDE4LB2SE5ESVovnN5KApf49rP8ejE6eadN5Ox9OgvoqV/4TUy4RSXJ4NAPLe3X/sHDmt8Nh+ES9++zGB5CIBQsjULIX3qJl16cxDMI7lLRP/Ab3DluM+KUqibfpHS5nGDOskrLzDPZ0+3BkScXZ4Oc1HzYZu+63Ao= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jo1cRGUN; 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="jo1cRGUN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 01D9AC4CECD; Thu, 14 Nov 2024 22:49:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1731624565; bh=lACSCrdzRLG5x1E+njLfHcgssYzowjsw+9YGqqUEk5I=; h=Date:From:To:Cc:Subject:From; b=jo1cRGUNxfABfeEOZv9PLK4KjN69C/Kdsq3mfouhwGEWZuVFooQhG7JYRAKWI4txE Yz9jO0fFHl8ey2nqakGiyjnD8ynEsjMrvyBRw3nfGXjhtw8wb0VK2ZzLLHaogEQHUk SGD5WvzhU0xhmTTYl6JJ1yk21eXZ86bkJzw4Hm+Ebecb+XRrdgFkarvxcKq49myWPU nTA1Gu4RyMYBSb4Yn0VeKugjBCD5LUk7adNx+bMsst5C9YYNAa9VO15wCLLSzPCb6d +ARAQxl1WudwwxmejfVwgxRDWh4cDJI94LJ8fVaMw6JfFdJOV6/PAYBg1D/lTbwX37 kEGJHmcyZufqQ== Date: Thu, 14 Nov 2024 16:49:21 -0600 From: "Gustavo A. R. Silva" To: Yinbo Zhu , Michael Turquette , Stephen Boyd , Binbin Zhou , Huacai Chen Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH] clk: clk-loongson2: Fix memory corruption bug in struct loongson2_clk_provider Message-ID: Precedence: bulk X-Mailing-List: linux-clk@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline Some heap space is allocated for the flexible structure `struct clk_hw_onecell_data` and its flexible-array member `hws` through the composite structure `struct loongson2_clk_provider` in function `loongson2_clk_probe()`, as shown below: 289 struct loongson2_clk_provider *clp; ... 296 for (p = data; p->name; p++) 297 clks_num++; 298 299 clp = devm_kzalloc(dev, struct_size(clp, clk_data.hws, clks_num), 300 GFP_KERNEL); Then some data is written into the flexible array: 350 clp->clk_data.hws[p->id] = hw; This corrupts `clk_lock`, which is the spinlock variable immediately following the `clk_data` member in `struct loongson2_clk_provider`: struct loongson2_clk_provider { void __iomem *base; struct device *dev; struct clk_hw_onecell_data clk_data; spinlock_t clk_lock; /* protect access to DIV registers */ }; The problem is that the flexible structure is currently placed in the middle of `struct loongson2_clk_provider` instead of at the end. Fix this by moving `struct clk_hw_onecell_data clk_data;` to the end of `struct loongson2_clk_provider`. Also, add a code comment to help prevent this from happening again in case new members are added to the structure in the future. This change also fixes the following -Wflex-array-member-not-at-end warning: drivers/clk/clk-loongson2.c:32:36: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end] Fixes: 9796ec0bd04b ("clk: clk-loongson2: Refactor driver for adding new platforms") Cc: stable@vger.kernel.org Signed-off-by: Gustavo A. R. Silva --- drivers/clk/clk-loongson2.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/clk/clk-loongson2.c b/drivers/clk/clk-loongson2.c index 820bb1e9e3b7..e99ba79feec6 100644 --- a/drivers/clk/clk-loongson2.c +++ b/drivers/clk/clk-loongson2.c @@ -29,8 +29,10 @@ enum loongson2_clk_type { struct loongson2_clk_provider { void __iomem *base; struct device *dev; - struct clk_hw_onecell_data clk_data; spinlock_t clk_lock; /* protect access to DIV registers */ + + /* Must be last --ends in a flexible-array member. */ + struct clk_hw_onecell_data clk_data; }; struct loongson2_clk_data {