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 BBE5CC433EF for ; Thu, 20 Jan 2022 23:26:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347419AbiATX04 (ORCPT ); Thu, 20 Jan 2022 18:26:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41182 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237349AbiATX0z (ORCPT ); Thu, 20 Jan 2022 18:26:55 -0500 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 19BAEC06173F for ; Thu, 20 Jan 2022 15:26:55 -0800 (PST) Received: by mail-pj1-x1032.google.com with SMTP id s2-20020a17090ad48200b001b501977b23so7002649pju.2 for ; Thu, 20 Jan 2022 15:26:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=E4jTS0hzTbaXOxMszgYOI6HxWGtS6utH0hTeSFPdaW0=; b=mA5/U9dKnIwhf50QEn+qaQgEtZNumfBZk6HPiqajr4Yvjj3aTmSMjKaCLRjdf/Oc1Z Bt4TlG6lHDJP6lU7f2OZkwuJc1N0N4q4Jx6u2Uq+ldROEnlP6g1eYx62z5V5USnE4K+2 vQt3eTP67zcEqfP3rqTJ79eLWWnsMGGkqCEPA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=E4jTS0hzTbaXOxMszgYOI6HxWGtS6utH0hTeSFPdaW0=; b=Thr15xHo34DGGP4ZV64U78E52xYFsuSdvAEbfn0JV1aian2zq2/GSRIVZvMn9shq26 d99QbjH80xZ2sOadm6x/LnwjYmsl6+JyzxZNFqCzmQzwsR0w6vnVChxu1kU9HEv+vL6e Yc/Xs+xWcXrL9T905cOtJ6HDEus/19GNhMTsbQnSGbWbGZvcgF5WZFMFU4m3bm6u9+At obo5f95qvkC29GGOjaXu5AuqJxmCO5kPLZgmJZrgZd3WhYZaNsmF/5jvbNtqNDanjab/ yDDxa7zV06fdDfFgr0PwrMo1oefhnGoP5jaCFUsh5bMq4utaXnfrobejbfE8rfkqb69X J4PA== X-Gm-Message-State: AOAM533AMGn1W5KfMtZkzalzaLkLcVWlISTqxJWxkof1yr+LJ9nn1lPT jFn8xQ56OB/pxpygS1vq4Tiv5A== X-Google-Smtp-Source: ABdhPJxSJ9eqPJqMwbxURkdoAEcixxfln7sly/lADazdSPZgQAxAh00k8ttHV/EGfQVtRYIcJE8GwQ== X-Received: by 2002:a17:90b:4a04:: with SMTP id kk4mr1609497pjb.44.1642721214646; Thu, 20 Jan 2022 15:26:54 -0800 (PST) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id p38sm2610601pgb.36.2022.01.20.15.26.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Jan 2022 15:26:54 -0800 (PST) Date: Thu, 20 Jan 2022 15:26:53 -0800 From: Kees Cook To: "Gustavo A. R. Silva" Cc: Felipe Balbi , Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH][next] usb: gadget: f_fs: Use struct_size() and flex_array_size() helpers Message-ID: <202201201526.CE3DB41@keescook> References: <20220120222933.GA35155@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220120222933.GA35155@embeddedor> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, Jan 20, 2022 at 04:29:33PM -0600, Gustavo A. R. Silva wrote: > Make use of the struct_size() and flex_array_size() helpers instead of > an open-coded version, in order to avoid any potential type mistakes > or integer overflows that, in the worst scenario, could lead to heap > overflows. > > Also, address the following sparse warnings: > drivers/usb/gadget/function/f_fs.c:922:23: warning: using sizeof on a flexible structure > > Link: https://github.com/KSPP/linux/issues/174 > Signed-off-by: Gustavo A. R. Silva > --- > drivers/usb/gadget/function/f_fs.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c > index 25ad1e97a458..7461d27e9604 100644 > --- a/drivers/usb/gadget/function/f_fs.c > +++ b/drivers/usb/gadget/function/f_fs.c > @@ -919,12 +919,12 @@ static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile, > data_len, ret); > > data_len -= ret; > - buf = kmalloc(sizeof(*buf) + data_len, GFP_KERNEL); > + buf = kmalloc(struct_size(buf, storage, data_len), GFP_KERNEL); > if (!buf) > return -ENOMEM; > buf->length = data_len; > buf->data = buf->storage; > - memcpy(buf->storage, data + ret, data_len); > + memcpy(buf->storage, data + ret, flex_array_size(buf, storage, data_len)); Looks good to me. This is a place where I think we'll be back later to fix up the alloc/deserialize-from-memory pattern with a future helper, but in the meantime, yes, let's get this covered by struct_size(). Reviewed-by: Kees Cook > > /* > * At this point read_buffer is NULL or READ_BUFFER_DROP (if > -- > 2.27.0 > -- Kees Cook