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: 13424219 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 A4EAC381D8 for ; Mon, 16 Oct 2023 22:06:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ub0BOQHx" 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: Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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; }