diff options
Diffstat (limited to 'ipc/util.h')
| -rw-r--r-- | ipc/util.h | 207 |
1 files changed, 152 insertions, 55 deletions
diff --git a/ipc/util.h b/ipc/util.h index b6a6a88f3002..a55d6cebe6d3 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ /* * linux/ipc/util.h * Copyright (C) 1999 Christoph Rohland @@ -12,26 +13,57 @@ #include <linux/unistd.h> #include <linux/err.h> +#include <linux/ipc_namespace.h> +#include <linux/pid.h> -#define SEQ_MULTIPLIER (IPCMNI) +/* + * The IPC ID contains 2 separate numbers - index and sequence number. + * By default, + * bits 0-14: index (32k, 15 bits) + * bits 15-30: sequence number (64k, 16 bits) + * + * When IPCMNI extension mode is turned on, the composition changes: + * bits 0-23: index (16M, 24 bits) + * bits 24-30: sequence number (128, 7 bits) + */ +#define IPCMNI_SHIFT 15 +#define IPCMNI_EXTEND_SHIFT 24 +#define IPCMNI_EXTEND_MIN_CYCLE (RADIX_TREE_MAP_SIZE * RADIX_TREE_MAP_SIZE) +#define IPCMNI (1 << IPCMNI_SHIFT) +#define IPCMNI_EXTEND (1 << IPCMNI_EXTEND_SHIFT) + +#ifdef CONFIG_SYSVIPC_SYSCTL +extern int ipc_mni; +extern int ipc_mni_shift; +extern int ipc_min_cycle; + +#define ipcmni_seq_shift() ipc_mni_shift +#define IPCMNI_IDX_MASK ((1 << ipc_mni_shift) - 1) + +#else /* CONFIG_SYSVIPC_SYSCTL */ -void sem_init (void); -void msg_init (void); -void shm_init (void); +#define ipc_mni IPCMNI +#define ipc_min_cycle ((int)RADIX_TREE_MAP_SIZE) +#define ipcmni_seq_shift() IPCMNI_SHIFT +#define IPCMNI_IDX_MASK ((1 << IPCMNI_SHIFT) - 1) +#endif /* CONFIG_SYSVIPC_SYSCTL */ + +void sem_init(void); +void msg_init(void); +void shm_init(void); struct ipc_namespace; +struct pid_namespace; #ifdef CONFIG_POSIX_MQUEUE extern void mq_clear_sbinfo(struct ipc_namespace *ns); -extern void mq_put_mnt(struct ipc_namespace *ns); #else static inline void mq_clear_sbinfo(struct ipc_namespace *ns) { } -static inline void mq_put_mnt(struct ipc_namespace *ns) { } #endif #ifdef CONFIG_SYSVIPC void sem_init_ns(struct ipc_namespace *ns); -void msg_init_ns(struct ipc_namespace *ns); +int msg_init_ns(struct ipc_namespace *ns); void shm_init_ns(struct ipc_namespace *ns); void sem_exit_ns(struct ipc_namespace *ns); @@ -39,7 +71,7 @@ void msg_exit_ns(struct ipc_namespace *ns); void shm_exit_ns(struct ipc_namespace *ns); #else static inline void sem_init_ns(struct ipc_namespace *ns) { } -static inline void msg_init_ns(struct ipc_namespace *ns) { } +static inline int msg_init_ns(struct ipc_namespace *ns) { return 0; } static inline void shm_init_ns(struct ipc_namespace *ns) { } static inline void sem_exit_ns(struct ipc_namespace *ns) { } @@ -71,18 +103,19 @@ struct ipc_params { * . routine to call for an extra check if needed */ struct ipc_ops { - int (*getnew) (struct ipc_namespace *, struct ipc_params *); - int (*associate) (struct kern_ipc_perm *, int); - int (*more_checks) (struct kern_ipc_perm *, struct ipc_params *); + int (*getnew)(struct ipc_namespace *, struct ipc_params *); + int (*associate)(struct kern_ipc_perm *, int); + int (*more_checks)(struct kern_ipc_perm *, struct ipc_params *); }; struct seq_file; struct ipc_ids; -void ipc_init_ids(struct ipc_ids *); +void ipc_init_ids(struct ipc_ids *ids); #ifdef CONFIG_PROC_FS void __init ipc_init_proc_interface(const char *path, const char *header, int ids, int (*show)(struct seq_file *, void *)); +struct pid_namespace *ipc_seq_pid_ns(struct seq_file *); #else #define ipc_init_proc_interface(path, header, ids, show) do {} while (0) #endif @@ -91,72 +124,85 @@ void __init ipc_init_proc_interface(const char *path, const char *header, #define IPC_MSG_IDS 1 #define IPC_SHM_IDS 2 -#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER) -#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER) +#define ipcid_to_idx(id) ((id) & IPCMNI_IDX_MASK) +#define ipcid_to_seqx(id) ((id) >> ipcmni_seq_shift()) +#define ipcid_seq_max() (INT_MAX >> ipcmni_seq_shift()) -/* must be called with ids->rw_mutex acquired for writing */ +/* must be called with ids->rwsem acquired for writing */ int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int); -/* must be called with ids->rw_mutex acquired for reading */ -int ipc_get_maxid(struct ipc_ids *); - /* must be called with both locks acquired. */ void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); +/* must be called with both locks acquired. */ +void ipc_set_key_private(struct ipc_ids *, struct kern_ipc_perm *); + /* must be called with ipcp locked */ int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flg); -/* for rare, potentially huge allocations. - * both function can sleep +/** + * ipc_get_maxidx - get the highest assigned index + * @ids: ipc identifier set + * + * The function returns the highest assigned index for @ids. The function + * doesn't scan the idr tree, it uses a cached value. + * + * Called with ipc_ids.rwsem held for reading. */ -void* ipc_alloc(int size); -void ipc_free(void* ptr, int size); +static inline int ipc_get_maxidx(struct ipc_ids *ids) +{ + if (ids->in_use == 0) + return -1; + + if (ids->in_use == ipc_mni) + return ipc_mni - 1; + + return ids->max_idx; +} /* * For allocation that need to be freed by RCU. * Objects are reference counted, they start with reference count 1. * getref increases the refcount, the putref call that reduces the recount * to 0 schedules the rcu destruction. Caller must guarantee locking. + * + * refcount is initialized by ipc_addid(), before that point call_rcu() + * must be used. */ -void* ipc_rcu_alloc(int size); -int ipc_rcu_getref(void *ptr); -void ipc_rcu_putref(void *ptr); +bool ipc_rcu_getref(struct kern_ipc_perm *ptr); +void ipc_rcu_putref(struct kern_ipc_perm *ptr, + void (*func)(struct rcu_head *head)); -struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int); -struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id); +struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id); void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out); void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out); int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out); -struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, +struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns, struct ipc_ids *ids, int id, int cmd, struct ipc64_perm *perm, int extra_perm); -struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns, - struct ipc_ids *ids, int id, int cmd, - struct ipc64_perm *perm, int extra_perm); -#ifndef CONFIG_ARCH_WANT_IPC_PARSE_VERSION - /* On IA-64, we always use the "64-bit version" of the IPC structures. */ -# define ipc_parse_version(cmd) IPC_64 -#else -int ipc_parse_version (int *cmd); +static inline void ipc_update_pid(struct pid **pos, struct pid *pid) +{ + struct pid *old = *pos; + if (old != pid) { + *pos = get_pid(pid); + put_pid(old); + } +} + +#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION +int ipc_parse_version(int *cmd); #endif extern void free_msg(struct msg_msg *msg); -extern struct msg_msg *load_msg(const void __user *src, int len); +extern struct msg_msg *load_msg(const void __user *src, size_t len); extern struct msg_msg *copy_msg(struct msg_msg *src, struct msg_msg *dst); -extern int store_msg(void __user *dest, struct msg_msg *msg, int len); - -extern void recompute_msgmni(struct ipc_namespace *); - -static inline int ipc_buildid(int id, int seq) -{ - return SEQ_MULTIPLIER * seq + id; -} +extern int store_msg(void __user *dest, struct msg_msg *msg, size_t len); -static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid) +static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int id) { - return uid / SEQ_MULTIPLIER != ipcp->seq; + return ipcid_to_seqx(id) != ipcp->seq; } static inline void ipc_lock_object(struct kern_ipc_perm *perm) @@ -174,22 +220,73 @@ static inline void ipc_assert_locked_object(struct kern_ipc_perm *perm) assert_spin_locked(&perm->lock); } -static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm) -{ - rcu_read_lock(); - ipc_lock_object(perm); -} - static inline void ipc_unlock(struct kern_ipc_perm *perm) { ipc_unlock_object(perm); rcu_read_unlock(); } -struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id); +/* + * ipc_valid_object() - helper to sort out IPC_RMID races for codepaths + * where the respective ipc_ids.rwsem is not being held down. + * Checks whether the ipc object is still around or if it's gone already, as + * ipc_rmid() may have already freed the ID while the ipc lock was spinning. + * Needs to be called with kern_ipc_perm.lock held -- exception made for one + * checkpoint case at sys_semtimedop() as noted in code commentary. + */ +static inline bool ipc_valid_object(struct kern_ipc_perm *perm) +{ + return !perm->deleted; +} + struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id); int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, - struct ipc_ops *ops, struct ipc_params *params); + const struct ipc_ops *ops, struct ipc_params *params); void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)); + +static inline int sem_check_semmni(struct ipc_namespace *ns) { + /* + * Check semmni range [0, ipc_mni] + * semmni is the last element of sem_ctls[4] array + */ + return ((ns->sem_ctls[3] < 0) || (ns->sem_ctls[3] > ipc_mni)) + ? -ERANGE : 0; +} + +#ifdef CONFIG_COMPAT +#include <linux/compat.h> +struct compat_ipc_perm { + key_t key; + __compat_uid_t uid; + __compat_gid_t gid; + __compat_uid_t cuid; + __compat_gid_t cgid; + compat_mode_t mode; + unsigned short seq; +}; + +void to_compat_ipc_perm(struct compat_ipc_perm *, struct ipc64_perm *); +void to_compat_ipc64_perm(struct compat_ipc64_perm *, struct ipc64_perm *); +int get_compat_ipc_perm(struct ipc64_perm *, struct compat_ipc_perm __user *); +int get_compat_ipc64_perm(struct ipc64_perm *, + struct compat_ipc64_perm __user *); + +static inline int compat_ipc_parse_version(int *cmd) +{ + int version = *cmd & IPC_64; + *cmd &= ~IPC_64; + return version; +} + +long compat_ksys_old_semctl(int semid, int semnum, int cmd, int arg); +long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr); +long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz, + compat_long_t msgtyp, int msgflg); +long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp, + compat_ssize_t msgsz, int msgflg); +long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr); + +#endif + #endif |