4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
commit 16a34adb9392b2fe4195267475ab5b472e55292c upstream.
We want it only for the stuff created by SB_KERNMOUNT mounts, *not* for
their copies. As it is, creating a deep stack of bindings of /proc/*/ns/*
somewhere in a new namespace and exiting yields a stack overflow.
Cc: stable@xxxxxxxxxx
Reported-by: Alexander Aring <aring@xxxxxxxxxxxx>
Bisected-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Tested-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Tested-by: Alexander Aring <aring@xxxxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/namespace.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1033,7 +1033,8 @@ static struct mount *clone_mnt(struct mo
goto out_free;
}
- mnt->mnt.mnt_flags = old->mnt.mnt_flags & ~(MNT_WRITE_HOLD|MNT_MARKED);
+ mnt->mnt.mnt_flags = old->mnt.mnt_flags;
+ mnt->mnt.mnt_flags &= ~(MNT_WRITE_HOLD|MNT_MARKED|MNT_INTERNAL);
/* Don't allow unprivileged users to change mount flags */
if (flag & CL_UNPRIVILEGED) {
mnt->mnt.mnt_flags |= MNT_LOCK_ATIME;