• E
    vfs: Don't copy mount bind mounts of /proc/<pid>/ns/mnt between namespaces · 4ce5d2b1
    Eric W. Biederman 提交于
    Don't copy bind mounts of /proc/<pid>/ns/mnt between namespaces.
    These files hold references to a mount namespace and copying them
    between namespaces could result in a reference counting loop.
    
    The current mnt_ns_loop test prevents loops on the assumption that
    mounts don't cross between namespaces.  Unfortunately unsharing a
    mount namespace and shared substrees can both cause mounts to
    propogate between mount namespaces.
    
    Add two flags CL_COPY_UNBINDABLE and CL_COPY_MNT_NS_FILE are added to
    control this behavior, and CL_COPY_ALL is redefined as both of them.
    Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
    4ce5d2b1
pnode.h 1.5 KB
/*
 *  linux/fs/pnode.h
 *
 * (C) Copyright IBM Corporation 2005.
 *	Released under GPL v2.
 *
 */
#ifndef _LINUX_PNODE_H
#define _LINUX_PNODE_H

#include <linux/list.h>
#include "mount.h"

#define IS_MNT_SHARED(m) ((m)->mnt.mnt_flags & MNT_SHARED)
#define IS_MNT_SLAVE(m) ((m)->mnt_master)
#define IS_MNT_NEW(m)  (!(m)->mnt_ns)
#define CLEAR_MNT_SHARED(m) ((m)->mnt.mnt_flags &= ~MNT_SHARED)
#define IS_MNT_UNBINDABLE(m) ((m)->mnt.mnt_flags & MNT_UNBINDABLE)

#define CL_EXPIRE    		0x01
#define CL_SLAVE     		0x02
#define CL_COPY_UNBINDABLE	0x04
#define CL_MAKE_SHARED 		0x08
#define CL_PRIVATE 		0x10
#define CL_SHARED_TO_SLAVE	0x20
#define CL_UNPRIVILEGED		0x40
#define CL_COPY_MNT_NS_FILE	0x80

#define CL_COPY_ALL		(CL_COPY_UNBINDABLE | CL_COPY_MNT_NS_FILE)

static inline void set_mnt_shared(struct mount *mnt)
{
	mnt->mnt.mnt_flags &= ~MNT_SHARED_MASK;
	mnt->mnt.mnt_flags |= MNT_SHARED;
}

void change_mnt_propagation(struct mount *, int);
int propagate_mnt(struct mount *, struct mountpoint *, struct mount *,
		struct list_head *);
int propagate_umount(struct list_head *);
int propagate_mount_busy(struct mount *, int);
void mnt_release_group_id(struct mount *);
int get_dominating_id(struct mount *mnt, const struct path *root);
unsigned int mnt_get_count(struct mount *mnt);
void mnt_set_mountpoint(struct mount *, struct mountpoint *,
			struct mount *);
void umount_tree(struct mount *, int);
struct mount *copy_tree(struct mount *, struct dentry *, int);
bool is_path_reachable(struct mount *, struct dentry *,
			 const struct path *root);
#endif /* _LINUX_PNODE_H */
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