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=-9.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 A431DC433E7 for ; Tue, 13 Oct 2020 14:06:30 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0F010247B4 for ; Tue, 13 Oct 2020 14:06:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="C4g3fhac" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F010247B4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=containers-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id DD91787AF4; Tue, 13 Oct 2020 14:06:29 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id e4SwKQMT0bQl; Tue, 13 Oct 2020 14:06:29 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id 34DB787AD1; Tue, 13 Oct 2020 14:06:29 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 22382C07FF; Tue, 13 Oct 2020 14:06:29 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) by lists.linuxfoundation.org (Postfix) with ESMTP id D535CC0051 for ; Tue, 13 Oct 2020 14:06:27 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id BD37A87AF4 for ; Tue, 13 Oct 2020 14:06:27 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id LAn4l-62tI5f for ; Tue, 13 Oct 2020 14:06:26 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by whitealder.osuosl.org (Postfix) with ESMTPS id 6CD6A87AD1 for ; Tue, 13 Oct 2020 14:06:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602597985; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5qT8jquoQOvD8a7SF5l/rxB3mSNwZ5S4wf/Z1Ex1Krk=; b=C4g3fhac4/EUbQRJFosbmEcUMu6QtoiCvjATzMu4MtjFkweEvgX8otLmwrsgQt1pVsBbXm yekwKhym70O/kfc2BfKHiNXuJeHHlndbEO83GvngH+77eHQaaI446RV6zYJbBId54IQqJJ ocakZvhV6JCniMcK8NcGRsXbtfJSnbI= 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-166-XJGwe52cPvKPEYN1yPVNBg-1; Tue, 13 Oct 2020 10:06:23 -0400 X-MC-Unique: XJGwe52cPvKPEYN1yPVNBg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0DDD5805722; Tue, 13 Oct 2020 14:06:22 +0000 (UTC) Received: from lithium.redhat.com (ovpn-112-43.ams2.redhat.com [10.36.112.43]) by smtp.corp.redhat.com (Postfix) with ESMTP id 77A015C1C2; Tue, 13 Oct 2020 14:06:20 +0000 (UTC) From: Giuseppe Scrivano To: linux-kernel@vger.kernel.org Subject: [PATCH 1/2] fs, close_range: add flag CLOSE_RANGE_CLOEXEC Date: Tue, 13 Oct 2020 16:06:08 +0200 Message-Id: <20201013140609.2269319-2-gscrivan@redhat.com> In-Reply-To: <20201013140609.2269319-1-gscrivan@redhat.com> References: <20201013140609.2269319-1-gscrivan@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Cc: linux-fsdevel@vger.kernel.org, containers@lists.linux-foundation.org, viro@zeniv.linux.org.uk X-BeenThere: containers@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux Containers List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: containers-bounces@lists.linux-foundation.org Sender: "Containers" When the flag CLOSE_RANGE_CLOEXEC is set, close_range doesn't immediately close the files but it sets the close-on-exec bit. Signed-off-by: Giuseppe Scrivano --- fs/file.c | 56 ++++++++++++++++++++++---------- include/uapi/linux/close_range.h | 3 ++ 2 files changed, 42 insertions(+), 17 deletions(-) diff --git a/fs/file.c b/fs/file.c index 21c0893f2f1d..ad4ebee41e09 100644 --- a/fs/file.c +++ b/fs/file.c @@ -672,6 +672,17 @@ int __close_fd(struct files_struct *files, unsigned fd) } EXPORT_SYMBOL(__close_fd); /* for ksys_close() */ +static unsigned int __get_max_fds(struct files_struct *cur_fds) +{ + unsigned int max_fds; + + rcu_read_lock(); + /* cap to last valid index into fdtable */ + max_fds = files_fdtable(cur_fds)->max_fds; + rcu_read_unlock(); + return max_fds; +} + /** * __close_range() - Close all file descriptors in a given range. * @@ -683,27 +694,23 @@ EXPORT_SYMBOL(__close_fd); /* for ksys_close() */ */ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) { - unsigned int cur_max; + unsigned int cur_max = UINT_MAX; struct task_struct *me = current; struct files_struct *cur_fds = me->files, *fds = NULL; - if (flags & ~CLOSE_RANGE_UNSHARE) + if (flags & ~(CLOSE_RANGE_UNSHARE | CLOSE_RANGE_CLOEXEC)) return -EINVAL; if (fd > max_fd) return -EINVAL; - rcu_read_lock(); - cur_max = files_fdtable(cur_fds)->max_fds; - rcu_read_unlock(); - - /* cap to last valid index into fdtable */ - cur_max--; - if (flags & CLOSE_RANGE_UNSHARE) { int ret; unsigned int max_unshare_fds = NR_OPEN_MAX; + /* cap to last valid index into fdtable */ + cur_max = __get_max_fds(cur_fds) - 1; + /* * If the requested range is greater than the current maximum, * we're closing everything so only copy all file descriptors @@ -724,16 +731,31 @@ int __close_range(unsigned fd, unsigned max_fd, unsigned int flags) swap(cur_fds, fds); } - max_fd = min(max_fd, cur_max); - while (fd <= max_fd) { - struct file *file; + if (flags & CLOSE_RANGE_CLOEXEC) { + struct fdtable *fdt; - file = pick_file(cur_fds, fd++); - if (!file) - continue; + spin_lock(&cur_fds->file_lock); + fdt = files_fdtable(cur_fds); + cur_max = fdt->max_fds - 1; + max_fd = min(max_fd, cur_max); + while (fd <= max_fd) + __set_close_on_exec(fd++, fdt); + spin_unlock(&cur_fds->file_lock); + } else { + /* Initialize cur_max if needed. */ + if (cur_max == UINT_MAX) + cur_max = __get_max_fds(cur_fds) - 1; + max_fd = min(max_fd, cur_max); + while (fd <= max_fd) { + struct file *file; - filp_close(file, cur_fds); - cond_resched(); + file = pick_file(cur_fds, fd++); + if (!file) + continue; + + filp_close(file, cur_fds); + cond_resched(); + } } if (fds) { diff --git a/include/uapi/linux/close_range.h b/include/uapi/linux/close_range.h index 6928a9fdee3c..2d804281554c 100644 --- a/include/uapi/linux/close_range.h +++ b/include/uapi/linux/close_range.h @@ -5,5 +5,8 @@ /* Unshare the file descriptor table before closing file descriptors. */ #define CLOSE_RANGE_UNSHARE (1U << 1) +/* Set the FD_CLOEXEC bit instead of closing the file descriptor. */ +#define CLOSE_RANGE_CLOEXEC (1U << 2) + #endif /* _UAPI_LINUX_CLOSE_RANGE_H */ -- 2.26.2 _______________________________________________ Containers mailing list Containers@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/containers