From patchwork Mon Oct 16 22:05:27 2023 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: 13424224 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CF9E0CDB474 for ; Mon, 16 Oct 2023 22:05:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=tDHthXVRtzRhfgmATcopM7+DPZrTcA7uebBljENrSoc=; b=T39ZdkWawUL5lY Lq8afJxFGv0njKZTgUQTQ2izHYYp6o2oyd5AIxan7ok/aKdKsFVuaa8jbNAjnUM39291y+wUgRLxy JEeBv9wPiwKtD9N3IMmYkaFGVR0dsfPN/RNmTs/si9TXuwwlzYgLpKxCDtCan7hNAEOBGuHtVs/sO nJRlqWRKITcRwmDSuBCxnlmOz+CYYZqSzk3c5A6YdgXVtqKBCUFOLJYEM+5e+GZpPhe0ZeFD2ypwK RMdIchJIr2SGm/Qwwzaon61NIDzN1PBwHf23Mza5gwJni3TCfnkRI9qMB6HUbWdY30/NLbZuGd9Rr lpeX8lLVseVt+i0vWquA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qsViS-00AfRh-0F; Mon, 16 Oct 2023 22:05:36 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qsViP-00AfR6-1N for linux-arm-kernel@lists.infradead.org; Mon, 16 Oct 2023 22:05:35 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 558B16108D; Mon, 16 Oct 2023 22:05:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B055DC433C8; Mon, 16 Oct 2023 22:05:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697493932; bh=yehbNpyhrwY+5OKnAwXS4+SAIG7u6g3BmUMck9Il2jw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=N0fXqiC/U/SkvoRP9HJgm0THGVBbiF6IhO5dpFY+zdoiIe/ZBAvJpbXJvU6lUGJir NuT9fgiYBvwwFQu2nAXYUWoIMeFe6A4M34JYdACEEgi1zJmHnfW6PhJESPRHgE/5B7 R6h41oq7jkuwITcR03Dk4Al1fMznT61PSovToKBbclkM7RLbfXcLi7sLlAEKgFvD2a 7Lnyy7jLPUkkW+sqopflFD59dZ1gSkWFs/dIsgBjlXdRCArOCIpAWMTsv/St6lqH+A nDgn2KuKu4WOPRNGhjJNI+fFK2N96j/YW2kWDVQep6tWqGAuVHoevDH0N7FzvPzo45 FVt3PX1jkyPrQ== Date: Mon, 16 Oct 2023 16:05:27 -0600 From: "Gustavo A. R. Silva" To: Michael Turquette , Stephen Boyd , Nobuhiro Iwamatsu Cc: Kees Cook , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH v2 1/2][next] clk: visconti: Fix undefined behavior bug in struct visconti_pll_provider Message-ID: <57a831d94ee2b3889b11525d4ad500356f89576f.1697492890.git.gustavoars@kernel.org> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231016_150533_549646_FEFF0434 X-CRM114-Status: GOOD ( 17.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org `struct clk_hw_onecell_data` is a flexible structure, which means that it contains flexible-array member at the bottom, in this case array `hws`: include/linux/clk-provider.h: 1380 struct clk_hw_onecell_data { 1381 unsigned int num; 1382 struct clk_hw *hws[] __counted_by(num); 1383 }; This could potentially lead to an overwrite of the objects following `clk_data` in `struct visconti_pll_provider`, in this case `struct device_node *node;`, at run-time: drivers/clk/visconti/pll.h: 16 struct visconti_pll_provider { 17 void __iomem *reg_base; 18 struct clk_hw_onecell_data clk_data; 19 struct device_node *node; 20 }; Notice that a total of 56 bytes are allocated for flexible-array `hws` at line 328. See below: include/dt-bindings/clock/toshiba,tmpv770x.h: 14 #define TMPV770X_NR_PLL 7 drivers/clk/visconti/pll-tmpv770x.c: 69 ctx = visconti_init_pll(np, reg_base, TMPV770X_NR_PLL); drivers/clk/visconti/pll.c: 321 struct visconti_pll_provider * __init visconti_init_pll(struct device_node *np, 322 void __iomem *base, 323 unsigned long nr_plls) 324 { 325 struct visconti_pll_provider *ctx; ... 328 ctx = kzalloc(struct_size(ctx, clk_data.hws, nr_plls), GFP_KERNEL); `struct_size(ctx, clk_data.hws, nr_plls)` above translates to sizeof(struct visconti_pll_provider) + sizeof(struct clk_hw *) * 7 == 24 + 8 * 7 == 24 + 56 ^^^^ | allocated bytes for flex array `hws` $ pahole -C visconti_pll_provider drivers/clk/visconti/pll.o struct visconti_pll_provider { void * reg_base; /* 0 8 */ struct clk_hw_onecell_data clk_data; /* 8 8 */ struct device_node * node; /* 16 8 */ /* size: 24, cachelines: 1, members: 3 */ /* last cacheline: 24 bytes */ }; And then, after the allocation, some data is written into all members of `struct visconti_pll_provider`: 332 for (i = 0; i < nr_plls; ++i) 333 ctx->clk_data.hws[i] = ERR_PTR(-ENOENT); 334 335 ctx->node = np; 336 ctx->reg_base = base; 337 ctx->clk_data.num = nr_plls; Fix all these by placing the declaration of object `clk_data` at the end of `struct visconti_pll_provider`. Also, add a comment to make it clear that this object must always be last in the structure, and prevent this bug from being introduced again in the future. -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting ready to enable it globally. Fixes: b4cbe606dc36 ("clk: visconti: Add support common clock driver and reset driver") Cc: stable@vger.kernel.org Reviewed-by: Kees Cook Acked-by: Nobuhiro Iwamatsu Signed-off-by: Gustavo A. R. Silva --- Changes in v2: - Mention -Wflex-array-member-not-at-end in the changelog text. v1: - Link: https://lore.kernel.org/linux-hardening/0a59a721d54b557076cc94eabeb694d463773204.1697076650.git.gustavoars@kernel.org/ drivers/clk/visconti/pll.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/clk/visconti/pll.h b/drivers/clk/visconti/pll.h index 01d07f1bf01b..c4bd40676da4 100644 --- a/drivers/clk/visconti/pll.h +++ b/drivers/clk/visconti/pll.h @@ -15,8 +15,10 @@ struct visconti_pll_provider { void __iomem *reg_base; - struct clk_hw_onecell_data clk_data; struct device_node *node; + + /* Must be last */ + struct clk_hw_onecell_data clk_data; }; #define VISCONTI_PLL_RATE(_rate, _dacen, _dsmen, \ From patchwork Mon Oct 16 22:06:16 2023 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: 13424225 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 61EACCDB465 for ; Mon, 16 Oct 2023 22:06:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=9wW1qlTfYsiR/HCzoa9PAUYykpmrgRzvCPZPuZ7g4Pk=; b=m71u3nqa3+49X6 vEfWAABhlEyuUHedVJvJyQd6jNaTIE58sPbV1j8WNjvIBo+b1ZUeQSy/U8Sq4iZhBtGGv1zWFAXQn DdOkOttAHmXknQ5X7mLmmKB4IYqs29nKIfk+b/YMtztZrPhJbcHKrB9+ljBipTK+QuMOkaDUNeQwz Z9RUh03LdAk8xHOvpNFMUwA+uQxtQFmSXr/S4a6alZbSoEcQhlQ+vtQXyPjUDNFpI7G+iYa1psB3C Xh2izGArzPBEWMKb8DX1kkPRrPN4FGyR59y0zwTgx+0YHbNroLO6xVC5BZGjBmw5XxTZXxSEo1jmz ukL6bnITPaZDReap1Ulg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qsVjF-00AfWc-2y; Mon, 16 Oct 2023 22:06:25 +0000 Received: from sin.source.kernel.org ([2604:1380:40e1:4800::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qsVjD-00AfVq-0A for linux-arm-kernel@lists.infradead.org; Mon, 16 Oct 2023 22:06:24 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id E593DCE1B3B; Mon, 16 Oct 2023 22:06:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B94CDC433C7; Mon, 16 Oct 2023 22:06:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697493980; bh=D7fdEpe0zShD1pFuLK68iJJXBS2qGwVgntab6FWqrjo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ub0BOQHxbWbUL85k9CgeLDCVNKg+n4jXSewv2gYqW1hfR3aBKTBygdAWyh75PAjOW jxg8DoU0PVbfCtkElQZVFZhb+qZ0dHh/NM3NNWXtsgMFMEDTQvpiiaSWoqczCfTNNv KWG92ncXKedXiJKitRh4LxKowpJicMN50Gik79sg4/ZLAnuVbCymw+Npe8nTmRE4rF QQ68eBToPSHUGgVEMlMFAimZYnXuF9hQ+U2O5FMrPuoVmUK5IV4MqHayLzhJF6L4qf tXNXSQJriezup5YH64Mfc7OMl+GsOyUjow+VZIAUKCoVJ6PRPrqb8IjJKPcZ2Khqde GtamlmfPp70ug== Date: Mon, 16 Oct 2023 16:06:16 -0600 From: "Gustavo A. R. Silva" To: Michael Turquette , Stephen Boyd , Nobuhiro Iwamatsu Cc: Kees Cook , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" , linux-hardening@vger.kernel.org Subject: [PATCH v2 2/2][next] clk: visconti: Add bounds-checking coverage for struct visconti_pll_provider Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231016_150623_431258_8A42DC2E X-CRM114-Status: GOOD ( 15.54 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In order to gain the bounds-checking coverage that __counted_by provides to flexible-array members at run-time via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions), we must make sure that the counter member, in this particular case `num`, is updated before the first access to the flex-array member, in this particular case array `hws`. See below: commit f316cdff8d67 ("clk: Annotate struct clk_hw_onecell_data with __counted_by") introduced `__counted_by` for `struct clk_hw_onecell_data` together with changes to relocate some of assignments of counter `num` before `hws` is accessed: include/linux/clk-provider.h: 1380 struct clk_hw_onecell_data { 1381 unsigned int num; 1382 struct clk_hw *hws[] __counted_by(num); 1383 }; However, this structure is used as a member in other structs, in this case in `struct visconti_pll_provider`: drivers/clk/visconti/pll.h: 16 struct visconti_pll_provider { 17 void __iomem *reg_base; 18 struct device_node *node; 19 20 /* Must be last */ 21 struct clk_hw_onecell_data clk_data; 22 }; Hence, we need to move the assignments to `ctx->clk_data.num` after allocation for `struct visconti_pll_provider` and before accessing the flexible array `ctx->clk_data.hws`. And, as assignments for all members in `struct visconti_pll_provider` are originally adjacent to each other, relocate all assignments together, so we don't split up `ctx->clk_data.hws = nr_plls` from the rest. :) Reviewed-by: Kees Cook Acked-by: Nobuhiro Iwamatsu Signed-off-by: Gustavo A. R. Silva --- Changes in v2: - None. v1: - Link: https://lore.kernel.org/linux-hardening/675633f7ae9893371d35b238f06fd02a3acffebb.1697076650.git.gustavoars@kernel.org/ drivers/clk/visconti/pll.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/clk/visconti/pll.c b/drivers/clk/visconti/pll.c index 1f3234f22667..e9cd80e085dc 100644 --- a/drivers/clk/visconti/pll.c +++ b/drivers/clk/visconti/pll.c @@ -329,12 +329,12 @@ struct visconti_pll_provider * __init visconti_init_pll(struct device_node *np, if (!ctx) return ERR_PTR(-ENOMEM); - for (i = 0; i < nr_plls; ++i) - ctx->clk_data.hws[i] = ERR_PTR(-ENOENT); - ctx->node = np; ctx->reg_base = base; ctx->clk_data.num = nr_plls; + for (i = 0; i < nr_plls; ++i) + ctx->clk_data.hws[i] = ERR_PTR(-ENOENT); + return ctx; }