ext4: zero out the unused memory region in the extent tree block

[mirror_ubuntu-bionic-kernel.git] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index 9d1374ab6e06f2cd7b57aedf196c53a745a1a683..91a3040f0cd0708b5cdfff22aac30cfcbe85dafa 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -517,6 +517,7 @@ void __mnt_drop_write(struct vfsmount *mnt)
        mnt_dec_writers(real_mount(mnt));
        preempt_enable();
 }
+EXPORT_SYMBOL_GPL(__mnt_drop_write);
 
 /**
  * mnt_drop_write - give up write access to a mount
@@ -846,6 +847,13 @@ static inline int check_mnt(struct mount *mnt)
        return mnt->mnt_ns == current->nsproxy->mnt_ns;
 }
 
+/* for aufs, CONFIG_AUFS_BR_FUSE */
+int is_current_mnt_ns(struct vfsmount *mnt)
+{
+       return check_mnt(real_mount(mnt));
+}
+EXPORT_SYMBOL_GPL(is_current_mnt_ns);
+
 /*
  * vfsmount lock must be held for write
  */
@@ -1089,7 +1097,8 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
                        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;
@@ -1589,7 +1598,7 @@ static int do_umount(struct mount *mnt, int flags)
                 * Special case for "unmounting" root ...
                 * we just try to remount it readonly.
                 */
-               if (!capable(CAP_SYS_ADMIN))
+               if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
                        return -EPERM;
                down_write(&sb->s_umount);
                if (!sb_rdonly(sb))
@@ -1600,8 +1609,13 @@ static int do_umount(struct mount *mnt, int flags)
 
        namespace_lock();
        lock_mount_hash();
-       event++;
 
+       /* Recheck MNT_LOCKED with the locks held */
+       retval = -EINVAL;
+       if (mnt->mnt.mnt_flags & MNT_LOCKED)
+               goto out;
+
+       event++;
        if (flags & MNT_DETACH) {
                if (!list_empty(&mnt->mnt_list))
                        umount_tree(mnt, UMOUNT_PROPAGATE);
@@ -1615,6 +1629,7 @@ static int do_umount(struct mount *mnt, int flags)
                        retval = 0;
                }
        }
+out:
        unlock_mount_hash();
        namespace_unlock();
        return retval;
@@ -1705,7 +1720,7 @@ SYSCALL_DEFINE2(umount, char __user *, name, int, flags)
                goto dput_and_out;
        if (!check_mnt(mnt))
                goto dput_and_out;
-       if (mnt->mnt.mnt_flags & MNT_LOCKED)
+       if (mnt->mnt.mnt_flags & MNT_LOCKED) /* Check optimistically */
                goto dput_and_out;
        retval = -EPERM;
        if (flags & MNT_FORCE && !capable(CAP_SYS_ADMIN))
@@ -1783,8 +1798,14 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
                for (s = r; s; s = next_mnt(s, r)) {
                        if (!(flag & CL_COPY_UNBINDABLE) &&
                            IS_MNT_UNBINDABLE(s)) {
-                               s = skip_mnt_tree(s);
-                               continue;
+                               if (s->mnt.mnt_flags & MNT_LOCKED) {
+                                       /* Both unbindable and locked. */
+                                       q = ERR_PTR(-EPERM);
+                                       goto out;
+                               } else {
+                                       s = skip_mnt_tree(s);
+                                       continue;
+                               }
                        }
                        if (!(flag & CL_COPY_MNT_NS_FILE) &&
                            is_mnt_ns_file(s->mnt.mnt_root)) {
@@ -1881,6 +1902,7 @@ int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
        }
        return 0;
 }
+EXPORT_SYMBOL_GPL(iterate_mounts);
 
 static void cleanup_group_ids(struct mount *mnt, struct mount *end)
 {
@@ -2327,7 +2349,7 @@ static int do_remount(struct path *path, int ms_flags, int sb_flags,
        down_write(&sb->s_umount);
        if (ms_flags & MS_BIND)
                err = change_mount_flags(path->mnt, ms_flags);
-       else if (!capable(CAP_SYS_ADMIN))
+       else if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
                err = -EPERM;
        else
                err = do_remount_sb(sb, sb_flags, data, 0);
@@ -2809,7 +2831,7 @@ long do_mount(const char *dev_name, const char __user *dir_name,
                mnt_flags |= MNT_NODIRATIME;
        if (flags & MS_STRICTATIME)
                mnt_flags &= ~(MNT_RELATIME | MNT_NOATIME);
-       if (flags & SB_RDONLY)
+       if (flags & MS_RDONLY)
                mnt_flags |= MNT_READONLY;
 
        /* The default atime for remount is preservation */