forked from luck/tmp_suning_uos_patched
f2a8d52e0a
Add a simple struct nsset. It holds all necessary pieces to switch to a new set of namespaces without leaving a task in a half-switched state which we will make use of in the next patch. This patch switches the existing setns logic over without causing a change in setns() behavior. This brings setns() closer to how unshare() works(). The prepare_ns() function is responsible to prepare all necessary information. This has two reasons. First it minimizes dependencies between individual namespaces, i.e. all install handler can expect that all fields are properly initialized independent in what order they are called in. Second, this makes the code easier to maintain and easier to follow if it needs to be changed. The prepare_ns() helper will only be switched over to use a flags argument in the next patch. Here it will still use nstype as a simple integer argument which was argued would be clearer. I'm not particularly opinionated about this if it really helps or not. The struct nsset itself already contains the flags field since its name already indicates that it can contain information required by different namespaces. None of this should have functional consequences. Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Reviewed-by: Serge Hallyn <serge@hallyn.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Serge Hallyn <serge@hallyn.com> Cc: Jann Horn <jannh@google.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Link: https://lore.kernel.org/r/20200505140432.181565-2-christian.brauner@ubuntu.com
90 lines
2.6 KiB
C
90 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* procfs namespace bits
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*/
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#ifndef _LINUX_PROC_NS_H
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#define _LINUX_PROC_NS_H
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#include <linux/ns_common.h>
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struct pid_namespace;
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struct nsset;
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struct path;
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struct task_struct;
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struct inode;
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struct proc_ns_operations {
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const char *name;
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const char *real_ns_name;
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int type;
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struct ns_common *(*get)(struct task_struct *task);
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void (*put)(struct ns_common *ns);
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int (*install)(struct nsset *nsset, struct ns_common *ns);
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struct user_namespace *(*owner)(struct ns_common *ns);
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struct ns_common *(*get_parent)(struct ns_common *ns);
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} __randomize_layout;
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extern const struct proc_ns_operations netns_operations;
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extern const struct proc_ns_operations utsns_operations;
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extern const struct proc_ns_operations ipcns_operations;
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extern const struct proc_ns_operations pidns_operations;
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extern const struct proc_ns_operations pidns_for_children_operations;
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extern const struct proc_ns_operations userns_operations;
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extern const struct proc_ns_operations mntns_operations;
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extern const struct proc_ns_operations cgroupns_operations;
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extern const struct proc_ns_operations timens_operations;
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extern const struct proc_ns_operations timens_for_children_operations;
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/*
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* We always define these enumerators
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*/
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enum {
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PROC_ROOT_INO = 1,
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PROC_IPC_INIT_INO = 0xEFFFFFFFU,
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PROC_UTS_INIT_INO = 0xEFFFFFFEU,
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PROC_USER_INIT_INO = 0xEFFFFFFDU,
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PROC_PID_INIT_INO = 0xEFFFFFFCU,
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PROC_CGROUP_INIT_INO = 0xEFFFFFFBU,
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PROC_TIME_INIT_INO = 0xEFFFFFFAU,
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};
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#ifdef CONFIG_PROC_FS
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extern int proc_alloc_inum(unsigned int *pino);
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extern void proc_free_inum(unsigned int inum);
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#else /* CONFIG_PROC_FS */
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static inline int proc_alloc_inum(unsigned int *inum)
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{
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*inum = 1;
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return 0;
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}
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static inline void proc_free_inum(unsigned int inum) {}
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#endif /* CONFIG_PROC_FS */
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static inline int ns_alloc_inum(struct ns_common *ns)
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{
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atomic_long_set(&ns->stashed, 0);
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return proc_alloc_inum(&ns->inum);
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}
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#define ns_free_inum(ns) proc_free_inum((ns)->inum)
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extern struct file *proc_ns_fget(int fd);
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#define get_proc_ns(inode) ((struct ns_common *)(inode)->i_private)
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extern int ns_get_path(struct path *path, struct task_struct *task,
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const struct proc_ns_operations *ns_ops);
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typedef struct ns_common *ns_get_path_helper_t(void *);
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extern int ns_get_path_cb(struct path *path, ns_get_path_helper_t ns_get_cb,
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void *private_data);
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extern bool ns_match(const struct ns_common *ns, dev_t dev, ino_t ino);
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extern int ns_get_name(char *buf, size_t size, struct task_struct *task,
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const struct proc_ns_operations *ns_ops);
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extern void nsfs_init(void);
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#endif /* _LINUX_PROC_NS_H */
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