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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03C8EC43334 for ; Tue, 5 Jul 2022 12:27:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237401AbiGEM1O (ORCPT ); Tue, 5 Jul 2022 08:27:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237617AbiGEMZn (ORCPT ); Tue, 5 Jul 2022 08:25:43 -0400 Received: from sin.source.kernel.org (sin.source.kernel.org [145.40.73.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39F501164; Tue, 5 Jul 2022 05:18:09 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id A6D57CE1A4A; Tue, 5 Jul 2022 12:18:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40F73C341C7; Tue, 5 Jul 2022 12:18:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657023485; bh=Oawlwwo/4Hrt5C49vgCr5vZAAwjn3HytdMXcRZDPBi8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fObLtPwvy1Onux9qKDnIqYthdCqHW8dmFKIynssgk22Qk7fGLFZ8vzNF6zBu/R92w ycAKf147F5h39iX3jyAbRJwOQWAZGyYJyboM3f14tEPqWDoXpvldxxU/z4yaqi6Xse pLVxdR1J9T9YXRIJU9MqjabIKdHcgOsLxAfNH+hc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Amir Goldstein , Jan Kara Subject: [PATCH 5.18 075/102] fanotify: refine the validation checks on non-dir inode mask Date: Tue, 5 Jul 2022 13:58:41 +0200 Message-Id: <20220705115620.539139567@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220705115618.410217782@linuxfoundation.org> References: <20220705115618.410217782@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Amir Goldstein commit 8698e3bab4dd7968666e84e111d0bfd17c040e77 upstream. Commit ceaf69f8eadc ("fanotify: do not allow setting dirent events in mask of non-dir") added restrictions about setting dirent events in the mask of a non-dir inode mark, which does not make any sense. For backward compatibility, these restictions were added only to new (v5.17+) APIs. It also does not make any sense to set the flags FAN_EVENT_ON_CHILD or FAN_ONDIR in the mask of a non-dir inode. Add these flags to the dir-only restriction of the new APIs as well. Move the check of the dir-only flags for new APIs into the helper fanotify_events_supported(), which is only called for FAN_MARK_ADD, because there is no need to error on an attempt to remove the dir-only flags from non-dir inode. Fixes: ceaf69f8eadc ("fanotify: do not allow setting dirent events in mask of non-dir") Link: https://lore.kernel.org/linux-fsdevel/20220627113224.kr2725conevh53u4@quack3.lan/ Link: https://lore.kernel.org/r/20220627174719.2838175-1-amir73il@gmail.com Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/notify/fanotify/fanotify_user.c | 34 +++++++++++++++++++--------------- include/linux/fanotify.h | 4 ++++ 2 files changed, 23 insertions(+), 15 deletions(-) --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -1483,8 +1483,15 @@ static int fanotify_test_fid(struct dent return 0; } -static int fanotify_events_supported(struct path *path, __u64 mask) +static int fanotify_events_supported(struct fsnotify_group *group, + struct path *path, __u64 mask, + unsigned int flags) { + unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS; + /* Strict validation of events in non-dir inode mask with v5.17+ APIs */ + bool strict_dir_events = FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID) || + (mask & FAN_RENAME); + /* * Some filesystems such as 'proc' acquire unusual locks when opening * files. For them fanotify permission events have high chances of @@ -1496,6 +1503,16 @@ static int fanotify_events_supported(str if (mask & FANOTIFY_PERM_EVENTS && path->mnt->mnt_sb->s_type->fs_flags & FS_DISALLOW_NOTIFY_PERM) return -EINVAL; + + /* + * We shouldn't have allowed setting dirent events and the directory + * flags FAN_ONDIR and FAN_EVENT_ON_CHILD in mask of non-dir inode, + * but because we always allowed it, error only when using new APIs. + */ + if (strict_dir_events && mark_type == FAN_MARK_INODE && + !d_is_dir(path->dentry) && (mask & FANOTIFY_DIRONLY_EVENT_BITS)) + return -ENOTDIR; + return 0; } @@ -1634,7 +1651,7 @@ static int do_fanotify_mark(int fanotify goto fput_and_out; if (flags & FAN_MARK_ADD) { - ret = fanotify_events_supported(&path, mask); + ret = fanotify_events_supported(group, &path, mask, flags); if (ret) goto path_put_and_out; } @@ -1657,19 +1674,6 @@ static int do_fanotify_mark(int fanotify else mnt = path.mnt; - /* - * FAN_RENAME is not allowed on non-dir (for now). - * We shouldn't have allowed setting any dirent events in mask of - * non-dir, but because we always allowed it, error only if group - * was initialized with the new flag FAN_REPORT_TARGET_FID. - */ - ret = -ENOTDIR; - if (inode && !S_ISDIR(inode->i_mode) && - ((mask & FAN_RENAME) || - ((mask & FANOTIFY_DIRENT_EVENTS) && - FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID)))) - goto path_put_and_out; - /* Mask out FAN_EVENT_ON_CHILD flag for sb/mount/non-dir marks */ if (mnt || !S_ISDIR(inode->i_mode)) { mask &= ~FAN_EVENT_ON_CHILD; --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -110,6 +110,10 @@ FANOTIFY_PERM_EVENTS | \ FAN_Q_OVERFLOW | FAN_ONDIR) +/* Events and flags relevant only for directories */ +#define FANOTIFY_DIRONLY_EVENT_BITS (FANOTIFY_DIRENT_EVENTS | \ + FAN_EVENT_ON_CHILD | FAN_ONDIR) + #define ALL_FANOTIFY_EVENT_BITS (FANOTIFY_OUTGOING_EVENTS | \ FANOTIFY_EVENT_FLAGS)