From patchwork Mon Oct 25 19:27:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gabriel Krisman Bertazi X-Patchwork-Id: 12582685 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AB85C43217 for ; Mon, 25 Oct 2021 19:33:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4835961184 for ; Mon, 25 Oct 2021 19:33:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235152AbhJYTff (ORCPT ); Mon, 25 Oct 2021 15:35:35 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:58632 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235751AbhJYTce (ORCPT ); Mon, 25 Oct 2021 15:32:34 -0400 Received: from localhost (unknown [IPv6:2804:14c:124:8a08::1002]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: krisman) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 5A6471F433CD; Mon, 25 Oct 2021 20:29:36 +0100 (BST) From: Gabriel Krisman Bertazi To: amir73il@gmail.com, jack@suse.com Cc: djwong@kernel.org, tytso@mit.edu, david@fromorbit.com, dhowells@redhat.com, khazhy@google.com, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-ext4@vger.kernel.org, Gabriel Krisman Bertazi , kernel@collabora.com, Jan Kara Subject: [PATCH v9 15/31] fanotify: Encode empty file handle when no inode is provided Date: Mon, 25 Oct 2021 16:27:30 -0300 Message-Id: <20211025192746.66445-16-krisman@collabora.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211025192746.66445-1-krisman@collabora.com> References: <20211025192746.66445-1-krisman@collabora.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Instead of failing, encode an invalid file handle in fanotify_encode_fh if no inode is provided. This bogus file handle will be reported by FAN_FS_ERROR for non-inode errors. Reviewed-by: Amir Goldstein Reviewed-by: Jan Kara Signed-off-by: Gabriel Krisman Bertazi --- Changes since v6: - Use FILEID_ROOT as the internal value (jan) - Create an empty FH (jan) Changes since v5: - Preserve flags initialization (jan) - Add BUILD_BUG_ON (amir) - Require minimum of FANOTIFY_NULL_FH_LEN for fh_len(amir) - Improve comment to explain the null FH length (jan) - Simplify logic --- fs/notify/fanotify/fanotify.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index ec84fee7ad01..c64d61b673ca 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -370,8 +370,14 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, fh->type = FILEID_ROOT; fh->len = 0; fh->flags = 0; + + /* + * Invalid FHs are used by FAN_FS_ERROR for errors not + * linked to any inode. The f_handle won't be reported + * back to userspace. + */ if (!inode) - return 0; + goto out; /* * !gpf means preallocated variable size fh, but fh_len could @@ -403,6 +409,7 @@ static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, fh->type = type; fh->len = fh_len; +out: /* * Mix fh into event merge key. Hash might be NULL in case of * unhashed FID events (i.e. FAN_FS_ERROR).