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 D8F77C433FE for ; Wed, 12 Oct 2022 22:07:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230050AbiJLWH4 (ORCPT ); Wed, 12 Oct 2022 18:07:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230028AbiJLWHa (ORCPT ); Wed, 12 Oct 2022 18:07:30 -0400 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 478863AE77 for ; Wed, 12 Oct 2022 15:05:41 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id o17-20020a17090aac1100b0020d98b0c0f4so1840334pjq.4 for ; Wed, 12 Oct 2022 15:05:41 -0700 (PDT) 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=4pGHWCM3N3OUCM1ER+rKkscIwlNTBChe1kgAgXac27k=; b=ZxJoRoLe4ZBw6t/WVbwcJncoE0viTUu8WwUYo7HbCWwah3umOJMh7nIangr40Amqkq 9W0ohHrMfNY+RUM2a81m+RD18ceXG+efXZmb0U/XCJCPPqQMUDOn4Ud9rbXn2edUNUgZ crmhtoIrm7mDYAljbxaMlHUxbJWvFs5GJQKj8= 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=4pGHWCM3N3OUCM1ER+rKkscIwlNTBChe1kgAgXac27k=; b=ebQs8eSpf4VrPnZaGl1V4oUzyJAPKADtiGWGs72jaek3FqoIOMDmjqQQPUCv+kLOga jtNrL+LWGyiV5rSD6dU6BrHqI5qd1VoF9rX7EEBxuGRRhSV73D9Z7n5NQpGce/6dsumd mx5eQcBvlLJcOUbZ+qLCZACXnDypT82d+AlYt8rBtrgZj7LmNLngaAsVYWTTE9Y2ztrn Gs1hPE8tWUTGgKYQmhGrhPH3abLAjCSlFUieOZfexmW1+uDulhOVUVGYrN8c6SLSBrHA SWR6u5Mu4wVFTgM3P4VtT5G/4RVGC5zLcB3ysHx4yXHPPDYGJ8DsfKonkjvThI0dMEZc bzBA== X-Gm-Message-State: ACrzQf06dz7vK6JCCYin8jp1biygqC3hTg++QH/znTwBWtlrZtn5+Oi8 Ko91+wpGJP9Bl2mg9pwejdd2LA== X-Google-Smtp-Source: AMsMyM5qJXypLtEuI7LmQWOcC6PZlx4jhq65/txaKudvas3aDV4YoebnKIfrSMm8JqEgIT2QXo2a9Q== X-Received: by 2002:a17:90b:400c:b0:20a:bb11:a0f3 with SMTP id ie12-20020a17090b400c00b0020abb11a0f3mr7423615pjb.166.1665612251178; Wed, 12 Oct 2022 15:04:11 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id w133-20020a62828b000000b0052d4b0d0c74sm360959pfd.70.2022.10.12.15.04.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Oct 2022 15:04:10 -0700 (PDT) Date: Wed, 12 Oct 2022 15:04:09 -0700 From: Kees Cook To: Casey Schaufler Cc: casey.schaufler@intel.com, paul@paul-moore.com, linux-security-module@vger.kernel.org, linux-audit@redhat.com, jmorris@namei.org, selinux@vger.kernel.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, stephen.smalley.work@gmail.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v38 39/39] LSM: Create lsm_module_list system call Message-ID: <202210121459.00980C2@keescook> References: <20220927195421.14713-1-casey@schaufler-ca.com> <20220927203155.15060-1-casey@schaufler-ca.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220927203155.15060-1-casey@schaufler-ca.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 27, 2022 at 01:31:55PM -0700, Casey Schaufler wrote: > +SYSCALL_DEFINE3(lsm_module_list, > + unsigned int __user *, ids, > + size_t __user *, size, > + int, flags) Please make this unsigned int. > +{ > + unsigned int *interum; > + size_t total_size = lsm_id * sizeof(*interum); > + size_t usize; > + int rc; > + int i; Please test that flags == 0 so it can be used in the future: if (flags) return -EINVAL; > + > + if (get_user(usize, size)) > + return -EFAULT; > + > + if (usize < total_size) { > + if (put_user(total_size, size) != 0) > + return -EFAULT; > + return -E2BIG; > + } > + > + interum = kzalloc(total_size, GFP_KERNEL); > + if (interum == NULL) > + return -ENOMEM; > + > + for (i = 0; i < lsm_id; i++) > + interum[i] = lsm_idlist[i]->id; > + > + if (copy_to_user(ids, interum, total_size) != 0 || > + put_user(total_size, size) != 0) > + rc = -EFAULT; No need to repeat this, if it is written first. > + else > + rc = lsm_id; > + > + kfree(interum); > + return rc; No need for the alloc/free. Here's what I would imagine for the whole thing: if (flags) return -EINVAL; if (get_user(usize, size)) return -EFAULT; if (put_user(total_size, size) != 0) return -EFAULT; if (usize < total_size) return -E2BIG; for (i = 0; i < lsm_id; i++) if (put_user(lsm_idlist[i]->id, id++)) return -EFAULT; return lsm_id; -- Kees Cook