From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E03A733E36A; Sat, 30 May 2026 18:32:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780165963; cv=none; b=tguUSN+dRGHHoK86fISXYnAXsAYfRi8fAtU6BsBoY3wyPi4/R2sSNGgxvqGR6knXiTkQCi6IKbmK5K1Y749bPz/TNlaI9eIB4NvHbOLFiHQWChVDjQvRJGAlhOWVm5mbcAA4QXjVCrGPIF1VzaFrSsiP/NyfAuY6+JJvRmzVFck= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780165963; c=relaxed/simple; bh=v+m7zKAcS+GbUINrwtViTH/QTiYdvcsTbRE/f/OEVbc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PiojvHECbciAcfpJpCgg9qJT0/bIj5mgo+iOCtbnEIhz3y0EXq8N6rvdWkaCNaUidHg2aIk4M9CMiBkyys1xnWroctaKV7sm73UYfMl1+UzgiaVsWVb6UXa55qg4RCgEc/Q6YNYDki8+dMShi5QE7nRx0MW797JcjekpXnGvVpo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=MU/AW+tc; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="MU/AW+tc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 284171F00893; Sat, 30 May 2026 18:32:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780165962; bh=X5VR9EvsV6jNSxs6oOKGdhSYe+np/o9jREhyp6ux64A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=MU/AW+tcElVL96CrxbB8r6V5fc1r60I7mao4mJZ7l3yuY7YY0ful96ewQ4QvL6AeM B6inW4j1U55cr/uCmkpGhKWEQm+S0mC9Zb6CwhB3rLFv3N5rZN5MAb99T3JcpqoTVb BbbVJmtL6KApWUj41Q3QdmGGSt2nnNhv950AizRw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Miklos Szeredi , Jan Kara Subject: [PATCH 5.10 233/589] fanotify: fix false positive on permission events Date: Sat, 30 May 2026 18:01:54 +0200 Message-ID: <20260530160231.110032040@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160224.570625122@linuxfoundation.org> References: <20260530160224.570625122@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miklos Szeredi commit 7746e3bd4cc19b5092e00d32d676e329bfcb6900 upstream. fsnotify_get_mark_safe() may return false for a mark on an unrelated group, which results in bypassing the permission check. Fix by skipping over detached marks that are not in the current group. CC: stable@vger.kernel.org Fixes: abc77577a669 ("fsnotify: Provide framework for dropping SRCU lock in ->handle_event") Signed-off-by: Miklos Szeredi Link: https://patch.msgid.link/20260410144950.156160-1-mszeredi@redhat.com Signed-off-by: Jan Kara Signed-off-by: Greg Kroah-Hartman --- fs/notify/fsnotify.c | 2 +- fs/notify/mark.c | 18 +++++++++++------- include/linux/fsnotify_backend.h | 1 + 3 files changed, 13 insertions(+), 8 deletions(-) --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -398,7 +398,7 @@ static struct fsnotify_mark *fsnotify_fi return hlist_entry_safe(node, struct fsnotify_mark, obj_list); } -static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark) +struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark) { struct hlist_node *node = NULL; --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -380,9 +380,6 @@ EXPORT_SYMBOL_GPL(fsnotify_put_mark); */ static bool fsnotify_get_mark_safe(struct fsnotify_mark *mark) { - if (!mark) - return true; - if (refcount_inc_not_zero(&mark->refcnt)) { spin_lock(&mark->lock); if (mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED) { @@ -423,15 +420,22 @@ bool fsnotify_prepare_user_wait(struct f int type; fsnotify_foreach_iter_type(type) { + struct fsnotify_mark *mark = iter_info->marks[type]; + /* This can fail if mark is being removed */ - if (!fsnotify_get_mark_safe(iter_info->marks[type])) { - __release(&fsnotify_mark_srcu); - goto fail; + while (mark && !fsnotify_get_mark_safe(mark)) { + if (mark->group == iter_info->current_group) { + __release(&fsnotify_mark_srcu); + goto fail; + } + /* This is a mark in an unrelated group, skip */ + mark = fsnotify_next_mark(mark); + iter_info->marks[type] = mark; } } /* - * Now that both marks are pinned by refcount in the inode / vfsmount + * Now that all marks are pinned by refcount in the inode / vfsmount / etc * lists, we can drop SRCU lock, and safely resume the list iteration * once userspace returns. */ --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -820,6 +820,7 @@ static inline void fsnotify_clear_sb_mar } extern void fsnotify_get_mark(struct fsnotify_mark *mark); extern void fsnotify_put_mark(struct fsnotify_mark *mark); +struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark); extern void fsnotify_finish_user_wait(struct fsnotify_iter_info *iter_info); extern bool fsnotify_prepare_user_wait(struct fsnotify_iter_info *iter_info);