/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_USER_NAMESPACE_H
#define _LINUX_USER_NAMESPACE_H

#include <linux/kref.h>
#include <linux/nsproxy.h>
#include <linux/ns_common.h>
#include <linux/rculist_nulls.h>
#include <linux/sched.h>
#include <linux/workqueue.h>
#include <linux/rcuref.h>
#include <linux/rwsem.h>
#include <linux/sysctl.h>
#include <linux/err.h>

#define UID_GID_MAP_MAX_BASE_EXTENTS 5
#define UID_GID_MAP_MAX_EXTENTS 340

struct uid_gid_extent {
        u32 first;
        u32 lower_first;
        u32 count;
};

struct uid_gid_map { /* 64 bytes -- 1 cache line */
        union {
                struct {
                        struct uid_gid_extent extent[UID_GID_MAP_MAX_BASE_EXTENTS];
                        u32 nr_extents;
                };
                struct {
                        struct uid_gid_extent *forward;
                        struct uid_gid_extent *reverse;
                };
        };
};

#define USERNS_SETGROUPS_ALLOWED 1UL

#define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED

struct ucounts;

enum ucount_type {
        UCOUNT_USER_NAMESPACES,
        UCOUNT_PID_NAMESPACES,
        UCOUNT_UTS_NAMESPACES,
        UCOUNT_IPC_NAMESPACES,
        UCOUNT_NET_NAMESPACES,
        UCOUNT_MNT_NAMESPACES,
        UCOUNT_CGROUP_NAMESPACES,
        UCOUNT_TIME_NAMESPACES,
#ifdef CONFIG_INOTIFY_USER
        UCOUNT_INOTIFY_INSTANCES,
        UCOUNT_INOTIFY_WATCHES,
#endif
#ifdef CONFIG_FANOTIFY
        UCOUNT_FANOTIFY_GROUPS,
        UCOUNT_FANOTIFY_MARKS,
#endif
        UCOUNT_COUNTS,
};

enum rlimit_type {
        UCOUNT_RLIMIT_NPROC,
        UCOUNT_RLIMIT_MSGQUEUE,
        UCOUNT_RLIMIT_SIGPENDING,
        UCOUNT_RLIMIT_MEMLOCK,
        UCOUNT_RLIMIT_COUNTS,
};

#if IS_ENABLED(CONFIG_BINFMT_MISC)
struct binfmt_misc;
#endif

struct user_namespace {
        struct uid_gid_map      uid_map;
        struct uid_gid_map      gid_map;
        struct uid_gid_map      projid_map;
        struct user_namespace   *parent;
        int                     level;
        kuid_t                  owner;
        kgid_t                  group;
        struct ns_common        ns;
        unsigned long           flags;
        /* parent_could_setfcap: true if the creator if this ns had CAP_SETFCAP
         * in its effective capability set at the child ns creation time. */
        bool                    parent_could_setfcap;

#ifdef CONFIG_KEYS
        /* List of joinable keyrings in this namespace.  Modification access of
         * these pointers is controlled by keyring_sem.  Once
         * user_keyring_register is set, it won't be changed, so it can be
         * accessed directly with READ_ONCE().
         */
        struct list_head        keyring_name_list;
        struct key              *user_keyring_register;
        struct rw_semaphore     keyring_sem;
#endif

        /* Register of per-UID persistent keyrings for this namespace */
#ifdef CONFIG_PERSISTENT_KEYRINGS
        struct key              *persistent_keyring_register;
#endif
        struct work_struct      work;
#ifdef CONFIG_SYSCTL
        struct ctl_table_set    set;
        struct ctl_table_header *sysctls;
#endif
        struct ucounts          *ucounts;
        long ucount_max[UCOUNT_COUNTS];
        long rlimit_max[UCOUNT_RLIMIT_COUNTS];

#if IS_ENABLED(CONFIG_BINFMT_MISC)
        struct binfmt_misc *binfmt_misc;
#endif
} __randomize_layout;

struct ucounts {
        struct hlist_nulls_node node;
        struct user_namespace *ns;
        kuid_t uid;
        struct rcu_head rcu;
        rcuref_t count;
        atomic_long_t ucount[UCOUNT_COUNTS];
        atomic_long_t rlimit[UCOUNT_RLIMIT_COUNTS];
};

extern struct user_namespace init_user_ns;
extern struct ucounts init_ucounts;

bool setup_userns_sysctls(struct user_namespace *ns);
void retire_userns_sysctls(struct user_namespace *ns);
struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid);
void put_ucounts(struct ucounts *ucounts);

static inline struct ucounts * __must_check get_ucounts(struct ucounts *ucounts)
{
        if (rcuref_get(&ucounts->count))
                return ucounts;
        return NULL;
}

static inline long get_rlimit_value(struct ucounts *ucounts, enum rlimit_type type)
{
        return atomic_long_read(&ucounts->rlimit[type]);
}

long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v);
long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type,
                            bool override_rlimit);
void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type);
bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long max);

static inline long get_userns_rlimit_max(struct user_namespace *ns, enum rlimit_type type)
{
        return READ_ONCE(ns->rlimit_max[type]);
}

static inline void set_userns_rlimit_max(struct user_namespace *ns,
                enum rlimit_type type, unsigned long max)
{
        ns->rlimit_max[type] = max <= LONG_MAX ? max : LONG_MAX;
}

static inline struct user_namespace *to_user_ns(struct ns_common *ns)
{
        return container_of(ns, struct user_namespace, ns);
}

#ifdef CONFIG_USER_NS

static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
{
        if (ns)
                ns_ref_inc(ns);
        return ns;
}

extern int create_user_ns(struct cred *new);
extern int unshare_userns(unsigned long unshare_flags, struct cred **new_cred);
extern void __put_user_ns(struct user_namespace *ns);

static inline void put_user_ns(struct user_namespace *ns)
{
        if (ns && ns_ref_put(ns))
                __put_user_ns(ns);
}

struct seq_operations;
extern const struct seq_operations proc_uid_seq_operations;
extern const struct seq_operations proc_gid_seq_operations;
extern const struct seq_operations proc_projid_seq_operations;
extern ssize_t proc_uid_map_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t proc_gid_map_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t, loff_t *);
extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
extern int proc_setgroups_show(struct seq_file *m, void *v);
extern bool userns_may_setgroups(const struct user_namespace *ns);
extern bool in_userns(const struct user_namespace *ancestor,
                       const struct user_namespace *child);
extern bool current_in_userns(const struct user_namespace *target_ns);
struct ns_common *ns_get_owner(struct ns_common *ns);
#else

static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
{
        return &init_user_ns;
}

static inline int create_user_ns(struct cred *new)
{
        return -EINVAL;
}

static inline int unshare_userns(unsigned long unshare_flags,
                                 struct cred **new_cred)
{
        if (unshare_flags & CLONE_NEWUSER)
                return -EINVAL;
        return 0;
}

static inline void put_user_ns(struct user_namespace *ns)
{
}

static inline bool userns_may_setgroups(const struct user_namespace *ns)
{
        return true;
}

static inline bool in_userns(const struct user_namespace *ancestor,
                             const struct user_namespace *child)
{
        return true;
}

static inline bool current_in_userns(const struct user_namespace *target_ns)
{
        return true;
}

static inline struct ns_common *ns_get_owner(struct ns_common *ns)
{
        return ERR_PTR(-EPERM);
}
#endif

#endif /* _LINUX_USER_H */