c876ad7682
Oleg pointed out that in a pid namespace the sequence. - pid 1 becomes a zombie - setns(thepidns), fork,... - reaping pid 1. - The injected processes exiting. Can lead to processes attempting access their child reaper and instead following a stale pointer. That waitpid for init can return before all of the processes in the pid namespace have exited is also unfortunate. Avoid these problems by disabling the allocation of new pids in a pid namespace when init dies, instead of when the last process in a pid namespace is reaped. Pointed-out-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
97 lines
2.2 KiB
C
97 lines
2.2 KiB
C
#ifndef _LINUX_PID_NS_H
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#define _LINUX_PID_NS_H
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#include <linux/sched.h>
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#include <linux/bug.h>
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#include <linux/mm.h>
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#include <linux/threads.h>
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#include <linux/nsproxy.h>
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#include <linux/kref.h>
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struct pidmap {
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atomic_t nr_free;
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void *page;
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};
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#define PIDMAP_ENTRIES ((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)
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struct bsd_acct_struct;
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struct pid_namespace {
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struct kref kref;
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struct pidmap pidmap[PIDMAP_ENTRIES];
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int last_pid;
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unsigned int nr_hashed;
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struct task_struct *child_reaper;
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struct kmem_cache *pid_cachep;
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unsigned int level;
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struct pid_namespace *parent;
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#ifdef CONFIG_PROC_FS
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struct vfsmount *proc_mnt;
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#endif
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#ifdef CONFIG_BSD_PROCESS_ACCT
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struct bsd_acct_struct *bacct;
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#endif
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struct user_namespace *user_ns;
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struct work_struct proc_work;
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kgid_t pid_gid;
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int hide_pid;
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int reboot; /* group exit code if this pidns was rebooted */
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unsigned int proc_inum;
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};
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extern struct pid_namespace init_pid_ns;
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#define PIDNS_HASH_ADDING (1U << 31)
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#ifdef CONFIG_PID_NS
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static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
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{
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if (ns != &init_pid_ns)
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kref_get(&ns->kref);
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return ns;
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}
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extern struct pid_namespace *copy_pid_ns(unsigned long flags,
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struct user_namespace *user_ns, struct pid_namespace *ns);
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extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
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extern int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd);
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extern void put_pid_ns(struct pid_namespace *ns);
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#else /* !CONFIG_PID_NS */
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#include <linux/err.h>
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static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns)
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{
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return ns;
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}
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static inline struct pid_namespace *copy_pid_ns(unsigned long flags,
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struct user_namespace *user_ns, struct pid_namespace *ns)
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{
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if (flags & CLONE_NEWPID)
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ns = ERR_PTR(-EINVAL);
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return ns;
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}
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static inline void put_pid_ns(struct pid_namespace *ns)
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{
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}
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static inline void zap_pid_ns_processes(struct pid_namespace *ns)
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{
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BUG();
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}
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static inline int reboot_pid_ns(struct pid_namespace *pid_ns, int cmd)
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{
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return 0;
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}
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#endif /* CONFIG_PID_NS */
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extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk);
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void pidhash_init(void);
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void pidmap_init(void);
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#endif /* _LINUX_PID_NS_H */
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