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 ED1D6C4332F for ; Fri, 11 Nov 2022 03:15:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230181AbiKKDPJ (ORCPT ); Thu, 10 Nov 2022 22:15:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53044 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231765AbiKKDPI (ORCPT ); Thu, 10 Nov 2022 22:15:08 -0500 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B49DCBE3E for ; Thu, 10 Nov 2022 19:15:07 -0800 (PST) Received: by mail-pf1-x42a.google.com with SMTP id y13so3796411pfp.7 for ; Thu, 10 Nov 2022 19:15:07 -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=bwfTiLzBNiq3UGSuRV53jnzzUVq8yp9gLs6VSoyYYIY=; b=gZCI8KVjBN7kl3vowgoO723z9038r1Q7Rn824uf1rMAzO0KPmQmYS9isn/OEPBSsHO zqAHD0ToyrZis6ESaYLdJB/CrYW2eQk/qY9eKlpAmGIGLtdM+yhpN7Y6RZTOz8SJ9h5u XE2xv1pKPkSpLbPoeUm/+tihq4ihjbcCBwBv0= 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=bwfTiLzBNiq3UGSuRV53jnzzUVq8yp9gLs6VSoyYYIY=; b=Wz+faLONByYU471RSCiYY++8U6u2I/lOx5d73ZbcB9Jwm/icoCTKQxo/RwW4tSkzN8 rc+V5y7gXdyX6CmS/HuwwLBJAYVLxMBD7ncncbqAIQIkgYOFmtgX+q7yJVjPLWfk0Xpb SpbWy+b6Q+QSO4WMeZeJQZVYW/1/olbAXvVf5GrLP1Lxqod50iY1aQud4SA3USc4CxSe E+KG2SAz79zYQ3xsqHRaIgObWH4JxOy611EIgek0xNluQlL3oUbEc+clbu7diActc7Vb 1lIFoPFcIfNmaw+rLXcfBiN4bO5xcRYzpH/qZALYkZlaDK/HtEPQd3gRanPcv7kELipl vhbw== X-Gm-Message-State: ANoB5pn7Z366wtoy3KsrbrM1LI/kQTu4zeDOFbeIK7JLRsiQlxBEJulB 60d7lqhsk90+XAILwRYDQnl7Aw== X-Google-Smtp-Source: AA0mqf7TQE+OkvPXRKVatlxKEdVrVGcR694siFnt5CSyd0ClsvheQbjo5FKS5cSiQ1WfM8aY/5cU9A== X-Received: by 2002:a63:d111:0:b0:473:ef9c:e1e5 with SMTP id k17-20020a63d111000000b00473ef9ce1e5mr1759870pgg.241.1668136507168; Thu, 10 Nov 2022 19:15:07 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id 186-20020a6206c3000000b00553d573222fsm387724pfg.199.2022.11.10.19.15.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 10 Nov 2022 19:15:06 -0800 (PST) Date: Thu, 10 Nov 2022 19:15:05 -0800 From: Kees Cook To: Sergey Senozhatsky Cc: Alexey Romanov , linux-kernel@vger.kernel.org, Nick Terrell , Minchan Kim , Suleiman Souhlal , Nitin Gupta , Jens Axboe , Nhat Pham , Andrew Morton , linux-block@vger.kernel.org, "Gustavo A. R. Silva" , linux-next@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: Coverity: zram_recompress(): OVERRUN Message-ID: <202211101904.7A0B0C3@keescook> References: <202211100847.388C61B3@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-next@vger.kernel.org On Fri, Nov 11, 2022 at 09:26:31AM +0900, Sergey Senozhatsky wrote: > On (22/11/10 08:47), coverity-bot wrote: > > *** CID 1527270: (OVERRUN) > > drivers/block/zram/zram_drv.c:1727 in zram_recompress() > > 1721 zstrm = zcomp_stream_get(zram->comps[prio]); > > 1722 src = kmap_atomic(page); > > 1723 ret = zcomp_compress(zstrm, src, &comp_len_new); > > 1724 kunmap_atomic(src); > > 1725 > > 1726 if (ret) { > > vvv CID 1527270: (OVERRUN) > > vvv Overrunning array "zram->comps" of 4 8-byte elements at element index 4 (byte offset 39) using index "prio" (which evaluates to 4). > > Hmm... I don't really see how prio can evaluate to 4. Yeah, I agree. This looks like a false positive. I'm not sure why Coverity triggered for it. Looking at the extended report, it seems to not have any idea that prio_max is correctly bounded. Sorry for the noise! -- Kees Cook