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From 0de0e610f6b359c52d4f8b02bac2963f4968c9d6 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Wed, 7 Jan 2015 14:28:26 -0600
Subject: mnt: Fail collect_mounts when applied to unmounted mounts
[ Upstream commit cd4a40174b71acd021877341684d8bb1dc8ea4ae ]
The only users of collect_mounts are in audit_tree.c
In audit_trim_trees and audit_add_tree_rule the path passed into
collect_mounts is generated from kern_path passed an audit_tree
pathname which is guaranteed to be an absolute path. In those cases
collect_mounts is obviously intended to work on mounted paths and
if a race results in paths that are unmounted when collect_mounts
it is reasonable to fail early.
The paths passed into audit_tag_tree don't have the absolute path
check. But are used to play with fsnotify and otherwise interact with
the audit_trees, so again operating only on mounted paths appears
reasonable.
Avoid having to worry about what happens when we try and audit
unmounted filesystems by restricting collect_mounts to mounts
that appear in the mount tree.
Fixes CVE-2015-4177.
Upstream-Status: Backport
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
---
fs/namespace.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 64837e3..8b60287 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1675,8 +1675,11 @@ struct vfsmount *collect_mounts(struct path *path)
{
struct mount *tree;
namespace_lock();
- tree = copy_tree(real_mount(path->mnt), path->dentry,
- CL_COPY_ALL | CL_PRIVATE);
+ if (!check_mnt(real_mount(path->mnt)))
+ tree = ERR_PTR(-EINVAL);
+ else
+ tree = copy_tree(real_mount(path->mnt), path->dentry,
+ CL_COPY_ALL | CL_PRIVATE);
namespace_unlock();
if (IS_ERR(tree))
return ERR_CAST(tree);
--
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