From 85f3ff439c5b35786160c79b34e0efb4a60b51d3 Mon Sep 17 00:00:00 2001
From: Nikolaus Rath <Nikolaus@rath.org>
Date: Tue, 2 Feb 2016 08:58:27 -0800
Subject: [PATCH] Fix description of bug #15.
---
README.md | 28 +++++++++++++++++++---------
1 file changed, 19 insertions(+), 9 deletions(-)
diff --git a/README.md b/README.md
index 9274d7b..2243a12 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,25 @@
libfuse
=======
+Warning: unresolved security issue
+----------------------------------
+
+Be aware that FUSE has an unresolved security bug
+([bug #15](https://github.com/libfuse/libfuse/issues/15)): the
+permission check for accessing a cached directory is only done once
+when the directory entry is first loaded into the cache. Subsequent
+accesses will re-use the results of the first check, even if the
+directory permissions have since changed, and even if the subsequent
+access is made by a different user.
+
+This bug needs to be fixed in the Linux kernel and has been known
+since 2006 but unfortunately no fix has been applied yet. If you
+depend on correct permission handling for FUSE file systems, the only
+workaround is to completely disable caching of directory
+entries. Alternatively, the severity of the bug can be somewhat
+reduced by not using the `allow_other` mount option.
+
+
About
-----
@@ -61,15 +80,6 @@ doing nasty things. Currently those limitations are:
mounted filesystem (though this can be relaxed by allowing the use
of the `allow_other` and `allow_root` mount options in `fuse.conf`)
-When using the `allow_other` option, be aware of
-[bug #15](https://github.com/libfuse/libfuse/issues/15): the
-permission to access a cached directory entry is only checked for the
-first user that accesses it. As long as the directory entry is cached,
-accesses by other users are made with the permissions of the first
-user. The only work around for this bug is to disable caching of
-directory entries, or to not use `allow_other`.
-
-
Building your own filesystem
------------------------------
--
2.30.2