| From | Kamal Mostafa <> | Subject | [PATCH 3.13.y-ckt 103/132] vfs: Ignore unlocked mounts in fs_fully_visible | Date | Wed, 22 Jul 2015 19:00:21 -0700 |
| |
3.13.11-ckt24 -stable review patch. If anyone has any objections, please let me know.
------------------
From: "Eric W. Biederman" <ebiederm@xmission.com>
commit ceeb0e5d39fcdf4dca2c997bf225c7fc49200b37 upstream.
Limit the mounts fs_fully_visible considers to locked mounts. Unlocked can always be unmounted so considering them adds hassle but no security benefit.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- fs/namespace.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/fs/namespace.c b/fs/namespace.c index dfe193a..df7bf37 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3031,11 +3031,15 @@ static bool fs_fully_visible(struct file_system_type *type, int *new_mnt_flags) ((mnt->mnt.mnt_flags & MNT_ATIME_MASK) != (new_flags & MNT_ATIME_MASK))) continue; - /* This mount is not fully visible if there are any child mounts - * that cover anything except for empty directories. + /* This mount is not fully visible if there are any + * locked child mounts that cover anything except for + * empty directories. */ list_for_each_entry(child, &mnt->mnt_mounts, mnt_child) { struct inode *inode = child->mnt_mountpoint->d_inode; + /* Only worry about locked mounts */ + if (!(mnt->mnt.mnt_flags & MNT_LOCKED)) + continue; if (!S_ISDIR(inode->i_mode)) goto next; if (inode->i_nlink > 2) -- 1.9.1
|