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=-9.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 ADC0EC65BAF for ; Wed, 12 Dec 2018 22:05:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F8F42086D for ; Wed, 12 Dec 2018 22:05:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="wgjIKIkD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6F8F42086D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joelfernandes.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728432AbeLLWF3 (ORCPT ); Wed, 12 Dec 2018 17:05:29 -0500 Received: from mail-pl1-f195.google.com ([209.85.214.195]:42502 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728405AbeLLWF1 (ORCPT ); Wed, 12 Dec 2018 17:05:27 -0500 Received: by mail-pl1-f195.google.com with SMTP id y1so9231778plp.9 for ; Wed, 12 Dec 2018 14:05:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=tojsaxYtzGw4VUa07hP8Iro7zYaRhBsbIH7KfTp/GN0=; b=wgjIKIkDhdzkYnqPDHKZG6Xkhtz0Z7oCA7Eg1VYG7Rw10AuS9/wFDzszGt3jE0RYpu BJDO5x6hN7NbIZ+3pENYYOHMmXRH8mXuCQtgV0Uxs4YABZFci9ybqXluC/gtrchX4v2q hgL89d7E5nOBsck6McZJqK7nN5qqNeWVyYDlQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=tojsaxYtzGw4VUa07hP8Iro7zYaRhBsbIH7KfTp/GN0=; b=tQHdn0vwriS4ihvxXlhfr9Xlw/oC/jupp2vGoX/ytkzhvqzWVzNQgicjxXprkncx/C T2ocDjs/dArvkA9itknSqiLwcvJhVoNxwuz7sNBBTPY/sLbYBYUYc+bdvGZ3IZsl1uyh 6RfEIl4/MQ9fnE1IpCSk/T4E/eIKT5c3dYAsW3VJXb6mkf/lMkmHIZyMfs3vUdvtMrgk 4/m3vH7guIrtth5JuVwcJjJT+uBrgz+K+0XBl33YI1WVXF9AFxmo6FJi0wOhYHaQEdp6 Mrj0pkkxB67DmeM6/XgPJ9jR7YZ+hTK4jQiZlem252EANqEjS4QIXm4jELBx1xoUZ4Q9 5QYA== X-Gm-Message-State: AA+aEWYeoVo+PbXV+W+3vLTzieT9XHAqQotVR0+pHNeT1/nlaP3LBNLM thg3kieFAv6OJc0e8k4Hm59NRg== X-Google-Smtp-Source: AFSGD/UxK1G+wZUhq2La4WFKV9b5McakIYhxYhtbWABuVRqk7kW6DZkuWJLa2mKrz+MYmpuudSOAJQ== X-Received: by 2002:a17:902:b48b:: with SMTP id y11mr20625930plr.200.1544652325579; Wed, 12 Dec 2018 14:05:25 -0800 (PST) Received: from joelaf.mtv.corp.google.com ([2620:0:1000:1601:3aef:314f:b9ea:889f]) by smtp.gmail.com with ESMTPSA id o1sm29340869pgn.63.2018.12.12.14.05.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Dec 2018 14:05:24 -0800 (PST) From: "Joel Fernandes (Google)" To: linux-man@vger.kernel.org Cc: "Joel Fernandes (Google)" , Andrew Morton , Andy Lutomirski , dancol@google.com, Hugh Dickins , Jann Horn , John Stultz , linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Matthew Wilcox , Mike Kravetz , Shuah Khan , Stephen Rothwell Subject: [PATCH -manpage 2/2] memfd_create.2: Update manpage with new memfd F_SEAL_FUTURE_WRITE seal Date: Wed, 12 Dec 2018 14:05:14 -0800 Message-Id: <20181212220514.205269-2-joel@joelfernandes.org> X-Mailer: git-send-email 2.20.0.rc1.387.gf8505762e3-goog In-Reply-To: <20181212220514.205269-1-joel@joelfernandes.org> References: <20181212220514.205269-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org More details of the seal can be found in the LKML patch: https://lore.kernel.org/lkml/20181120052137.74317-1-joel@joelfernandes.org/T/#t Signed-off-by: Joel Fernandes (Google) --- man2/memfd_create.2 | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/man2/memfd_create.2 b/man2/memfd_create.2 index 3cd392d1b4d9..fce2bf8d0fff 100644 --- a/man2/memfd_create.2 +++ b/man2/memfd_create.2 @@ -280,7 +280,15 @@ in order to restrict further modifications on the file. (If placing the seal .BR F_SEAL_WRITE , then it will be necessary to first unmap the shared writable mapping -created in the previous step.) +created in the previous step. Otherwise, behavior similar to +.BR F_SEAL_WRITE +can be achieved, by using +.BR F_SEAL_FUTURE_WRITE +which will prevent future writes via +.BR mmap (2) +and +.BR write (2) +from succeeding, while keeping existing shared writable mappings). .IP 4. A second process obtains a file descriptor for the .BR tmpfs (5) @@ -425,6 +433,7 @@ main(int argc, char *argv[]) fprintf(stderr, "\\t\\tg \- F_SEAL_GROW\\n"); fprintf(stderr, "\\t\\ts \- F_SEAL_SHRINK\\n"); fprintf(stderr, "\\t\\tw \- F_SEAL_WRITE\\n"); + fprintf(stderr, "\\t\\tW \- F_SEAL_FUTURE_WRITE\\n"); fprintf(stderr, "\\t\\tS \- F_SEAL_SEAL\\n"); exit(EXIT_FAILURE); } @@ -463,6 +472,8 @@ main(int argc, char *argv[]) seals |= F_SEAL_SHRINK; if (strchr(seals_arg, \(aqw\(aq) != NULL) seals |= F_SEAL_WRITE; + if (strchr(seals_arg, \(aqW\(aq) != NULL) + seals |= F_SEAL_FUTURE_WRITE; if (strchr(seals_arg, \(aqS\(aq) != NULL) seals |= F_SEAL_SEAL; @@ -518,6 +529,8 @@ main(int argc, char *argv[]) printf(" GROW"); if (seals & F_SEAL_WRITE) printf(" WRITE"); + if (seals & F_SEAL_FUTURE_WRITE) + printf(" FUTURE_WRITE"); if (seals & F_SEAL_SHRINK) printf(" SHRINK"); printf("\\n"); -- 2.20.0.rc1.387.gf8505762e3-goog