From mboxrd@z Thu Jan 1 00:00:00 1970 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 B41AAC4332F for ; Fri, 2 Dec 2022 18:54:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233958AbiLBSyh (ORCPT ); Fri, 2 Dec 2022 13:54:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42120 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234777AbiLBSyQ (ORCPT ); Fri, 2 Dec 2022 13:54:16 -0500 Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F359E8E1C for ; Fri, 2 Dec 2022 10:54:07 -0800 (PST) Received: by mail-pf1-x42d.google.com with SMTP id c7so2332359pfc.12 for ; Fri, 02 Dec 2022 10:54:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=6iMOnyAeQsAPxih1P0qQQ/qb4Uyj+szfK6Khgj7UVBM=; b=gaQZ/2L0TZuF0vlG6F8FXYeQZ1QCiQ4oPOli05DX+LfBfEE/JCeOzeHyX4Rb4cAwh+ k/u4J+C9Mk52XWfLFmd75lNLMXGn7Dx0sqmr8dAuRkfhivo330YgFt/EmYYp+wtltMgH uMFEkb6J4hTL10CrJZ9fffzLbBIQhIHL9CBLE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=6iMOnyAeQsAPxih1P0qQQ/qb4Uyj+szfK6Khgj7UVBM=; b=0oj9MRWK4Mbpmz8slVKv/jxXtCKPLmE774avSiwip/jVIxjfvS/cOg2+7vpNVBbwrL +i4gMBxu1pnYTy3FLJ+pKTTzFVO24nB64khtWlqklHBtxKvKgt978Hk+RI9QyzkPOkwD QjH8M5e0KoLHMVKEv5tD1PWrV9vJQVM3liOvDFHh8lNjERs5hZCxHDAGPiPA1OYXrDV4 DKd/aSbbV4DLw/Bop9QxMiz++WuIRzKF8LtVtogpCPMaTz2gJFx56s5cfzLd6xQsJNL5 yAM9kQYMos4P4zqWGmNBHs24EOBRiWqT9w4Vw5sBjft3g+Ml1M4emLZTImyLZbPKrs+Y jfYQ== X-Gm-Message-State: ANoB5pleJPiBMR7DuDXdMuBeGKHpLoOtsReHbamPqWwuZiu5F/zRGOxb vKsBs1aHEoAvHHmJgtq05lqTXA== X-Google-Smtp-Source: AA0mqf4oA/ZhqGNXZKsEB/aIA5GakcxaJJXeeAgFZIxsVTNBPLoZ+SknjDWJAkfMNj9dEspJpOKx4Q== X-Received: by 2002:a63:cd10:0:b0:476:c36a:42b9 with SMTP id i16-20020a63cd10000000b00476c36a42b9mr48440644pgg.235.1670007246921; Fri, 02 Dec 2022 10:54:06 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id s20-20020a170902a51400b001894dc5fdf2sm5859890plq.296.2022.12.02.10.54.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Dec 2022 10:54:06 -0800 (PST) Date: Fri, 2 Dec 2022 10:54:05 -0800 From: Kees Cook To: Herbert Xu Cc: Horia =?utf-8?Q?Geant=C4=83?= , Pankaj Gupta , Gaurav Jain , "David S. Miller" , linux-crypto@vger.kernel.org, kernel test robot , Anders Roxell , linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH v2] crypto/caam: Avoid GCC constprop bug warning Message-ID: <202212021049.16C438A@keescook> References: <20221202010410.gonna.444-kees@kernel.org> <202212011928.97A43D01@keescook> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 02, 2022 at 01:05:16PM +0800, Herbert Xu wrote: > On Thu, Dec 01, 2022 at 07:30:22PM -0800, Kees Cook wrote: > > > > Getting rid of the if doesn't solve the warning. I can switch it to just > > "if (data)", though. That keeps GCC happy. > > OK I misread the thread. > > Anyhow, it appears that this warning only occurs due to a debug > printk in caam. So how about something like this? What? I don't think that's true? I think CONFIG_CRYPTO_DEV_FSL_CAAM_DEBUG only controls "PRINT_POS", which is unrelated? The call path is: drivers/crypto/caam/key_gen.c: gen_split_key() append_fifo_load_as_imm(..., NULL, ...) <- literal NULL append_cmd_data(..., data, ...) memcpy(..., data, ...) and doesn't seem affected at all by CONFIG_CRYPTO_DEV_FSL_CAAM_DEBUG. -Kees > > diff --git a/drivers/crypto/caam/desc_constr.h b/drivers/crypto/caam/desc_constr.h > index 62ce6421bb3f..b49c995e1cc6 100644 > --- a/drivers/crypto/caam/desc_constr.h > +++ b/drivers/crypto/caam/desc_constr.h > @@ -163,7 +163,7 @@ static inline void append_data(u32 * const desc, const void *data, int len) > { > u32 *offset = desc_end(desc); > > - if (len) /* avoid sparse warning: memcpy with byte count of 0 */ > + if (!IS_ENABLED(CONFIG_CRYPTO_DEV_FSL_CAAM_DEBUG) || data) > memcpy(offset, data, len); > > (*desc) = cpu_to_caam32(caam32_to_cpu(*desc) + -- Kees Cook