mnt: Fail collect_mounts when applied to unmounted mounts
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.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/namespace.c b/fs/namespace.c
index 2b12b7a..acc5583 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1669,8 +1669,11 @@
{
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);