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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B2733C77B61 for ; Wed, 29 Mar 2023 17:14:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ieJ+Gxf4JYZn2CT7ry0N9Qqu8G/g6vU5xt3zeGzVvt8=; b=edtuDpyMuAbioR YemIo8t/2EYa6qlKQPz4wFzRgA9Y1KVwnKUbZPqepr97sjoCofIvUWt+/E9W+ObH9QF5f4lk/6s6D 35ZsD8GLshrAr2ivxgYZp8S1AX4IkN0jURi54xSt/Cms8gScNY6Z93D5qRqYgcYkcFhiQoPiIZIJM JsvZleRldg0sJtyNzzIo0i3NClI7w1RWzNz0LHSUpJcjed5zf2Wfg0aO3Xq9Gj4IMXJtcMB4XtqGS aLdbA1+3EVnRwoQqwMx8ynU8WVlPQiYwZODx4cUabK2/jgvfRm3cRryu0Jw56uKZAK90jdi1qPCS0 oxcAFXee+6COyp4lycaQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1phZMn-001GBB-2s; Wed, 29 Mar 2023 17:13:45 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1phZMl-001GAT-0P for linux-arm-kernel@lists.infradead.org; Wed, 29 Mar 2023 17:13:44 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1680110022; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=2HKY/Ux5TNZKEBOMV/tb21I2tofWYzDVBz54QvkxgBg=; b=fgHdvcaUYyNyOdUYtw25c2JBn74WQyvYjcdHcjJaRH9/TPANDJiAAKkhGlzgSurP1wYNds NyRod+1n5kTOI2++TBJ1k+N5TCE65M69tHr0oWlFgVO2ADLg+b40Zhwttb81NUCXZwFoYm SAPsQIUkUWWmWRJpjYX+lagNmaVxOes= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-93-wDlX7MaCPTeV1v8QlV9ksg-1; Wed, 29 Mar 2023 13:13:36 -0400 X-MC-Unique: wDlX7MaCPTeV1v8QlV9ksg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4B37485A588; Wed, 29 Mar 2023 17:13:35 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.224.161]) by smtp.corp.redhat.com (Postfix) with SMTP id 32E7F4020C82; Wed, 29 Mar 2023 17:13:30 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 29 Mar 2023 19:13:27 +0200 (CEST) Date: Wed, 29 Mar 2023 19:13:22 +0200 From: Oleg Nesterov To: Gregory Price Cc: Arnd Bergmann , Gregory Price , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Linux-Arch , avagin@gmail.com, Peter Zijlstra , Andy Lutomirski , krisman@collabora.com, Thomas Gleixner , Jonathan Corbet , shuah , Catalin Marinas , Will Deacon , Mark Rutland , tongtiangen@huawei.com, Robin Murphy Subject: Re: [PATCH v14 1/4] asm-generic,arm64: create task variant of access_ok Message-ID: <20230329171322.GB4477@redhat.com> References: <20230328164811.2451-1-gregory.price@memverge.com> <20230328164811.2451-2-gregory.price@memverge.com> <20230329151515.GA913@redhat.com> <9a456346-e207-44e1-873e-40d21334e01b@app.fastmail.com> <20230329160322.GA4477@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230329_101343_238457_E2E6322D X-CRM114-Status: GOOD ( 15.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 03/28, Gregory Price wrote: > > Not sure how I should proceed here, Can't we just kill this access_ok() in set_syscall_user_dispatch() ? I don't think it buys too much. Oleg. diff --git a/kernel/entry/syscall_user_dispatch.c b/kernel/entry/syscall_user_dispatch.c index 0b6379adff6b..d2e516ece52b 100644 --- a/kernel/entry/syscall_user_dispatch.c +++ b/kernel/entry/syscall_user_dispatch.c @@ -43,11 +43,7 @@ bool syscall_user_dispatch(struct pt_regs *regs) return false; if (likely(sd->selector)) { - /* - * access_ok() is performed once, at prctl time, when - * the selector is loaded by userspace. - */ - if (unlikely(__get_user(state, sd->selector))) { + if (unlikely(get_user(state, sd->selector))) { force_exit_sig(SIGSEGV); return true; } @@ -86,9 +82,6 @@ int set_syscall_user_dispatch(unsigned long mode, unsigned long offset, if (offset && offset + len <= offset) return -EINVAL; - if (selector && !access_ok(selector, sizeof(*selector))) - return -EFAULT; - break; default: return -EINVAL; _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel