132c94e31b
As a matter of policy MNT_READONLY should not be changable if the original mounter had more privileges than creator of the mount namespace. Add the flag CL_UNPRIVILEGED to note when we are copying a mount from a mount namespace that requires more privileges to a mount namespace that requires fewer privileges. When the CL_UNPRIVILEGED flag is set cause clone_mnt to set MNT_NO_REMOUNT if any of the mnt flags that should never be changed are set. This protects both mount propagation and the initial creation of a less privileged mount namespace. Cc: stable@vger.kernel.org Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/*
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* linux/fs/pnode.h
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*
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* (C) Copyright IBM Corporation 2005.
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* Released under GPL v2.
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*
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*/
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#ifndef _LINUX_PNODE_H
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#define _LINUX_PNODE_H
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#include <linux/list.h>
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#include "mount.h"
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#define IS_MNT_SHARED(m) ((m)->mnt.mnt_flags & MNT_SHARED)
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#define IS_MNT_SLAVE(m) ((m)->mnt_master)
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#define IS_MNT_NEW(m) (!(m)->mnt_ns)
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#define CLEAR_MNT_SHARED(m) ((m)->mnt.mnt_flags &= ~MNT_SHARED)
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#define IS_MNT_UNBINDABLE(m) ((m)->mnt.mnt_flags & MNT_UNBINDABLE)
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#define CL_EXPIRE 0x01
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#define CL_SLAVE 0x02
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#define CL_COPY_ALL 0x04
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#define CL_MAKE_SHARED 0x08
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#define CL_PRIVATE 0x10
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#define CL_SHARED_TO_SLAVE 0x20
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#define CL_UNPRIVILEGED 0x40
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static inline void set_mnt_shared(struct mount *mnt)
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{
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mnt->mnt.mnt_flags &= ~MNT_SHARED_MASK;
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mnt->mnt.mnt_flags |= MNT_SHARED;
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}
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void change_mnt_propagation(struct mount *, int);
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int propagate_mnt(struct mount *, struct dentry *, struct mount *,
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struct list_head *);
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int propagate_umount(struct list_head *);
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int propagate_mount_busy(struct mount *, int);
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void mnt_release_group_id(struct mount *);
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int get_dominating_id(struct mount *mnt, const struct path *root);
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unsigned int mnt_get_count(struct mount *mnt);
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void mnt_set_mountpoint(struct mount *, struct dentry *,
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struct mount *);
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void release_mounts(struct list_head *);
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void umount_tree(struct mount *, int, struct list_head *);
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struct mount *copy_tree(struct mount *, struct dentry *, int);
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bool is_path_reachable(struct mount *, struct dentry *,
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const struct path *root);
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#endif /* _LINUX_PNODE_H */
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