lkml.org 
[lkml]   [2018]   [Oct]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
SubjectRe: [PATCH 03/34] teach move_mount(2) to work with OPEN_TREE_CLONE [ver #12]
Date
Eric W. Biederman <ebiederm@xmission.com> wrote:

> It should just be a matter of replacing the test
> "if (p->mnt.mnt_sb->s_type == &nsfs)" with "if mnt_ns_loop(p->mnt.mnt_root)"

Okay, the attached seems to work.

Thanks,
David
---
diff --git a/fs/namespace.c b/fs/namespace.c
index e969ded7d54b..5548fb9b7de2 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2388,6 +2388,27 @@ static inline int tree_contains_unbindable(struct mount *mnt)
return 0;
}

+/*
+ * Object if there are any nsfs mounts in the specified subtree. These can act
+ * as pins for mount namespaces that aren't checked by the mount-cycle checking
+ * code, thereby allowing cycles to be made.
+ */
+static bool check_for_nsfs_mounts(struct mount *subtree)
+{
+ struct mount *p;
+ bool ret = false;
+
+ lock_mount_hash();
+ for (p = subtree; p; p = next_mnt(p, subtree))
+ if (mnt_ns_loop(p->mnt.mnt_root))
+ goto out;
+
+ ret = true;
+out:
+ unlock_mount_hash();
+ return ret;
+}
+
static int do_move_mount(struct path *old_path, struct path *new_path)
{
struct path parent_path = {.mnt = NULL, .dentry = NULL};
@@ -2442,6 +2463,8 @@ static int do_move_mount(struct path *old_path, struct path *new_path)
if (IS_MNT_SHARED(p) && tree_contains_unbindable(old))
goto out1;
err = -ELOOP;
+ if (!check_for_nsfs_mounts(old))
+ goto out1;
for (; mnt_has_parent(p); p = p->mnt_parent)
if (p == old)
goto out1;
\
 
 \ /
  Last update: 2018-10-11 22:19    [W:0.215 / U:0.568 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site