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 X-Spam-Level: X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 359A1C433B4 for ; Wed, 14 Apr 2021 16:56:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08C0F601FC for ; Wed, 14 Apr 2021 16:56:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234210AbhDNQ4Z (ORCPT ); Wed, 14 Apr 2021 12:56:25 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:27737 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233980AbhDNQ4X (ORCPT ); Wed, 14 Apr 2021 12:56:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618419361; 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=0XekfZf+wewTDqvutKV+4wFsWL6CSPJUUNNw63RFcjk=; b=fasna2/RbXSUU3s3J0U12h1YUpwpVTEv0/TDM6I0BKSdH9zG6Zj9HOr1TknExiubVMlAnn ZRoZGDZBvzg3j/eaPvund+5A4pa579K4me1FVs2pMw0opVxFW0mngepL+vCmYp46L3YNj7 y/V42Jy4T7QTae4mtP90yG3QVyNtelY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-538-0TGPAZATPW-ACxAz1fKdHg-1; Wed, 14 Apr 2021 12:55:58 -0400 X-MC-Unique: 0TGPAZATPW-ACxAz1fKdHg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 78F6E8189DE; Wed, 14 Apr 2021 16:55:50 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.40.192.65]) by smtp.corp.redhat.com (Postfix) with SMTP id E773B60877; Wed, 14 Apr 2021 16:55:48 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 14 Apr 2021 18:55:50 +0200 (CEST) Date: Wed, 14 Apr 2021 18:55:47 +0200 From: Oleg Nesterov To: David Laight Cc: He Zhe , Paul Moore , Eric Paris , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 2/2] ptrace: is_syscall_success: Add syscall return code handling for compat task Message-ID: <20210414165547.GA22294@redhat.com> References: <20210414080245.25476-1-zhe.he@windriver.com> <20210414150810.GA19371@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/14, David Laight wrote: > > From: Oleg Nesterov > > Sent: 14 April 2021 16:08 > > > > Add audit maintainers... > > > > On 04/14, He Zhe wrote: > > > > > > When 32-bit userspace application is running on 64-bit kernel, the 32-bit > > > syscall return code would be changed from u32 to u64 in regs_return_value > > > and then changed to s64. Hence the negative return code would be treated > > > as a positive number and results in a non-error in, for example, audit > > > like below. > > > > Sorry, can understand. At least on x86_64 even the 32-bit syscall returns > > long, not u32. > > > > Hmm. And afaics on x86 is_compat_task() is only defined if !CONFIG_COMPAT, > > so this patch looks wrong anyway. > > And, as with the other patch a x64_64 64bit process can make both types > of 32bit system call - so it needs to depend on the system call entry type > not any type of the task. I don't understand... but iirc is_compat_task() used to check TS_COMPAT and this is what we need to detect the 32-bit syscall. But it looks deprecated, I think in_compat_syscall() should be used instead. But this doesn't matter, I still can't understand the problem. Oleg.