diff options
Diffstat (limited to 'ipc/util.c')
| -rw-r--r-- | ipc/util.c | 1057 |
1 files changed, 627 insertions, 430 deletions
diff --git a/ipc/util.c b/ipc/util.c index 10e836d0d89..27d74e69fd5 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -7,25 +7,58 @@ * Occurs in several places in the IPC code. * Chris Evans, <chris@ferret.lmh.ox.ac.uk> * Nov 1999 - ipc helper functions, unified SMP locking - * Manfred Spraul <manfreds@colorfullife.com> + * Manfred Spraul <manfred@colorfullife.com> * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary(). * Mingming Cao <cmm@us.ibm.com> + * Mar 2006 - support for audit of ipc object properties + * Dustin Kirkland <dustin.kirkland@us.ibm.com> + * Jun 2006 - namespaces ssupport + * OpenVZ, SWsoft Inc. + * Pavel Emelianov <xemul@openvz.org> + * + * General sysv ipc locking scheme: + * rcu_read_lock() + * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr + * tree. + * - perform initial checks (capabilities, auditing and permission, + * etc). + * - perform read-only operations, such as STAT, INFO commands. + * acquire the ipc lock (kern_ipc_perm.lock) through + * ipc_lock_object() + * - perform data updates, such as SET, RMID commands and + * mechanism-specific operations (semop/semtimedop, + * msgsnd/msgrcv, shmat/shmdt). + * drop the ipc lock, through ipc_unlock_object(). + * rcu_read_unlock() + * + * The ids->rwsem must be taken when: + * - creating, removing and iterating the existing entries in ipc + * identifier sets. + * - iterating through files under /proc/sysvipc/ + * + * Note that sems have a special fast path that avoids kern_ipc_perm.lock - + * see sem_lock(). */ -#include <linux/config.h> #include <linux/mm.h> #include <linux/shm.h> #include <linux/init.h> #include <linux/msg.h> -#include <linux/smp_lock.h> #include <linux/vmalloc.h> #include <linux/slab.h> +#include <linux/notifier.h> +#include <linux/capability.h> #include <linux/highuid.h> #include <linux/security.h> #include <linux/rcupdate.h> #include <linux/workqueue.h> #include <linux/seq_file.h> #include <linux/proc_fs.h> +#include <linux/audit.h> +#include <linux/nsproxy.h> +#include <linux/rwsem.h> +#include <linux/memory.h> +#include <linux/ipc_namespace.h> #include <asm/unistd.h> @@ -34,80 +67,96 @@ struct ipc_proc_iface { const char *path; const char *header; - struct ipc_ids *ids; + int ids; int (*show)(struct seq_file *, void *); }; +static void ipc_memory_notifier(struct work_struct *work) +{ + ipcns_notify(IPCNS_MEMCHANGED); +} + +static int ipc_memory_callback(struct notifier_block *self, + unsigned long action, void *arg) +{ + static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier); + + switch (action) { + case MEM_ONLINE: /* memory successfully brought online */ + case MEM_OFFLINE: /* or offline: it's time to recompute msgmni */ + /* + * This is done by invoking the ipcns notifier chain with the + * IPC_MEMCHANGED event. + * In order not to keep the lock on the hotplug memory chain + * for too long, queue a work item that will, when waken up, + * activate the ipcns notification chain. + */ + schedule_work(&ipc_memory_wq); + break; + case MEM_GOING_ONLINE: + case MEM_GOING_OFFLINE: + case MEM_CANCEL_ONLINE: + case MEM_CANCEL_OFFLINE: + default: + break; + } + + return NOTIFY_OK; +} + +static struct notifier_block ipc_memory_nb = { + .notifier_call = ipc_memory_callback, + .priority = IPC_CALLBACK_PRI, +}; + /** - * ipc_init - initialise IPC subsystem + * ipc_init - initialise ipc subsystem + * + * The various sysv ipc resources (semaphores, messages and shared + * memory) are initialised. * - * The various system5 IPC resources (semaphores, messages and shared - * memory are initialised + * A callback routine is registered into the memory hotplug notifier + * chain: since msgmni scales to lowmem this callback routine will be + * called upon successful memory add / remove to recompute msmgni. */ - static int __init ipc_init(void) { sem_init(); msg_init(); shm_init(); + register_hotmemory_notifier(&ipc_memory_nb); + register_ipcns_notifier(&init_ipc_ns); return 0; } -__initcall(ipc_init); +device_initcall(ipc_init); /** - * ipc_init_ids - initialise IPC identifiers - * @ids: Identifier set - * @size: Number of identifiers + * ipc_init_ids - initialise ipc identifiers + * @ids: ipc identifier set * - * Given a size for the ipc identifier range (limited below IPCMNI) - * set up the sequence range to use then allocate and initialise the - * array itself. + * Set up the sequence range to use for the ipc identifier range (limited + * below IPCMNI) then initialise the ids idr. */ - -void __init ipc_init_ids(struct ipc_ids* ids, int size) +void ipc_init_ids(struct ipc_ids *ids) { - int i; - sema_init(&ids->sem,1); - - if(size > IPCMNI) - size = IPCMNI; ids->in_use = 0; - ids->max_id = -1; ids->seq = 0; - { - int seq_limit = INT_MAX/SEQ_MULTIPLIER; - if(seq_limit > USHRT_MAX) - ids->seq_max = USHRT_MAX; - else - ids->seq_max = seq_limit; - } - - ids->entries = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*size + - sizeof(struct ipc_id_ary)); - - if(ids->entries == NULL) { - printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n"); - size = 0; - ids->entries = &ids->nullentry; - } - ids->entries->size = size; - for(i=0;i<size;i++) - ids->entries->p[i] = NULL; + ids->next_id = -1; + init_rwsem(&ids->rwsem); + idr_init(&ids->ipcs_idr); } #ifdef CONFIG_PROC_FS -static struct file_operations sysvipc_proc_fops; +static const struct file_operations sysvipc_proc_fops; /** - * ipc_init_proc_interface - Create a proc interface for sysipc types - * using a seq_file interface. - * @path: Path in procfs - * @header: Banner to be printed at the beginning of the file. - * @ids: ipc id table to iterate. - * @show: show routine. + * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface. + * @path: Path in procfs + * @header: Banner to be printed at the beginning of the file. + * @ids: ipc id table to iterate. + * @show: show routine. */ void __init ipc_init_proc_interface(const char *path, const char *header, - struct ipc_ids *ids, - int (*show)(struct seq_file *, void *)) + int ids, int (*show)(struct seq_file *, void *)) { struct proc_dir_entry *pde; struct ipc_proc_iface *iface; @@ -120,361 +169,377 @@ void __init ipc_init_proc_interface(const char *path, const char *header, iface->ids = ids; iface->show = show; - pde = create_proc_entry(path, - S_IRUGO, /* world readable */ - NULL /* parent dir */); - if (pde) { - pde->data = iface; - pde->proc_fops = &sysvipc_proc_fops; - } else { + pde = proc_create_data(path, + S_IRUGO, /* world readable */ + NULL, /* parent dir */ + &sysvipc_proc_fops, + iface); + if (!pde) kfree(iface); - } } #endif /** - * ipc_findkey - find a key in an ipc identifier set - * @ids: Identifier set - * @key: The key to find - * - * Requires ipc_ids.sem locked. - * Returns the identifier if found or -1 if not. + * ipc_findkey - find a key in an ipc identifier set + * @ids: ipc identifier set + * @key: key to find + * + * Returns the locked pointer to the ipc structure if found or NULL + * otherwise. If key is found ipc points to the owning ipc structure + * + * Called with ipc_ids.rwsem held. */ - -int ipc_findkey(struct ipc_ids* ids, key_t key) +static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) { - int id; - struct kern_ipc_perm* p; - int max_id = ids->max_id; + struct kern_ipc_perm *ipc; + int next_id; + int total; - /* - * rcu_dereference() is not needed here - * since ipc_ids.sem is held - */ - for (id = 0; id <= max_id; id++) { - p = ids->entries->p[id]; - if(p==NULL) + for (total = 0, next_id = 0; total < ids->in_use; next_id++) { + ipc = idr_find(&ids->ipcs_idr, next_id); + + if (ipc == NULL) + continue; + + if (ipc->key != key) { + total++; continue; - if (key == p->key) - return id; + } + + rcu_read_lock(); + ipc_lock_object(ipc); + return ipc; } - return -1; + + return NULL; } -/* - * Requires ipc_ids.sem locked +/** + * ipc_get_maxid - get the last assigned id + * @ids: ipc identifier set + * + * Called with ipc_ids.rwsem held. */ -static int grow_ary(struct ipc_ids* ids, int newsize) -{ - struct ipc_id_ary* new; - struct ipc_id_ary* old; - int i; - int size = ids->entries->size; - - if(newsize > IPCMNI) - newsize = IPCMNI; - if(newsize <= size) - return newsize; - - new = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*newsize + - sizeof(struct ipc_id_ary)); - if(new == NULL) - return size; - new->size = newsize; - memcpy(new->p, ids->entries->p, sizeof(struct kern_ipc_perm *)*size + - sizeof(struct ipc_id_ary)); - for(i=size;i<newsize;i++) { - new->p[i] = NULL; - } - old = ids->entries; +int ipc_get_maxid(struct ipc_ids *ids) +{ + struct kern_ipc_perm *ipc; + int max_id = -1; + int total, id; - /* - * Use rcu_assign_pointer() to make sure the memcpyed contents - * of the new array are visible before the new array becomes visible. - */ - rcu_assign_pointer(ids->entries, new); + if (ids->in_use == 0) + return -1; - ipc_rcu_putref(old); - return newsize; + if (ids->in_use == IPCMNI) + return IPCMNI - 1; + + /* Look for the last assigned id */ + total = 0; + for (id = 0; id < IPCMNI && total < ids->in_use; id++) { + ipc = idr_find(&ids->ipcs_idr, id); + if (ipc != NULL) { + max_id = id; + total++; + } + } + return max_id; } /** - * ipc_addid - add an IPC identifier - * @ids: IPC identifier set - * @new: new IPC permission set - * @size: new size limit for the id array + * ipc_addid - add an ipc identifier + * @ids: ipc identifier set + * @new: new ipc permission set + * @size: limit for the number of used ids * - * Add an entry 'new' to the IPC arrays. The permissions object is - * initialised and the first free entry is set up and the id assigned - * is returned. The list is returned in a locked state on success. - * On failure the list is not locked and -1 is returned. + * Add an entry 'new' to the ipc ids idr. The permissions object is + * initialised and the first free entry is set up and the id assigned + * is returned. The 'new' entry is returned in a locked state on success. + * On failure the entry is not locked and a negative err-code is returned. * - * Called with ipc_ids.sem held. + * Called with writer ipc_ids.rwsem held. */ - -int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) +int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) { + kuid_t euid; + kgid_t egid; int id; + int next_id = ids->next_id; - size = grow_ary(ids,size); - - /* - * rcu_dereference()() is not needed here since - * ipc_ids.sem is held - */ - for (id = 0; id < size; id++) { - if(ids->entries->p[id] == NULL) - goto found; - } - return -1; -found: - ids->in_use++; - if (id > ids->max_id) - ids->max_id = id; + if (size > IPCMNI) + size = IPCMNI; - new->cuid = new->uid = current->euid; - new->gid = new->cgid = current->egid; + if (ids->in_use >= size) + return -ENOSPC; - new->seq = ids->seq++; - if(ids->seq > ids->seq_max) - ids->seq = 0; + idr_preload(GFP_KERNEL); spin_lock_init(&new->lock); - new->deleted = 0; + new->deleted = false; rcu_read_lock(); spin_lock(&new->lock); - ids->entries->p[id] = new; - return id; -} -/** - * ipc_rmid - remove an IPC identifier - * @ids: identifier set - * @id: Identifier to remove - * - * The identifier must be valid, and in use. The kernel will panic if - * fed an invalid identifier. The entry is removed and internal - * variables recomputed. The object associated with the identifier - * is returned. - * ipc_ids.sem and the spinlock for this ID is hold before this function - * is called, and remain locked on the exit. - */ - -struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id) -{ - struct kern_ipc_perm* p; - int lid = id % SEQ_MULTIPLIER; - if(lid >= ids->entries->size) - BUG(); - - /* - * do not need a rcu_dereference()() here to force ordering - * on Alpha, since the ipc_ids.sem is held. - */ - p = ids->entries->p[lid]; - ids->entries->p[lid] = NULL; - if(p==NULL) - BUG(); - ids->in_use--; + id = idr_alloc(&ids->ipcs_idr, new, + (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, + GFP_NOWAIT); + idr_preload_end(); + if (id < 0) { + spin_unlock(&new->lock); + rcu_read_unlock(); + return id; + } - if (lid == ids->max_id) { - do { - lid--; - if(lid == -1) - break; - } while (ids->entries->p[lid] == NULL); - ids->max_id = lid; + ids->in_use++; + + current_euid_egid(&euid, &egid); + new->cuid = new->uid = euid; + new->gid = new->cgid = egid; + + if (next_id < 0) { + new->seq = ids->seq++; + if (ids->seq > IPCID_SEQ_MAX) + ids->seq = 0; + } else { + new->seq = ipcid_to_seqx(next_id); + ids->next_id = -1; } - p->deleted = 1; - return p; + + new->id = ipc_buildid(id, new->seq); + return id; } /** - * ipc_alloc - allocate ipc space - * @size: size desired + * ipcget_new - create a new ipc object + * @ns: ipc namespace + * @ids: ipc identifer set + * @ops: the actual creation routine to call + * @params: its parameters * - * Allocate memory from the appropriate pools and return a pointer to it. - * NULL is returned if the allocation fails + * This routine is called by sys_msgget, sys_semget() and sys_shmget() + * when the key is IPC_PRIVATE. */ - -void* ipc_alloc(int size) +static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, + const struct ipc_ops *ops, struct ipc_params *params) { - void* out; - if(size > PAGE_SIZE) - out = vmalloc(size); - else - out = kmalloc(size, GFP_KERNEL); - return out; + int err; + + down_write(&ids->rwsem); + err = ops->getnew(ns, params); + up_write(&ids->rwsem); + return err; } /** - * ipc_free - free ipc space - * @ptr: pointer returned by ipc_alloc - * @size: size of block + * ipc_check_perms - check security and permissions for an ipc object + * @ns: ipc namespace + * @ipcp: ipc permission set + * @ops: the actual security routine to call + * @params: its parameters * - * Free a block created with ipc_alloc. The caller must know the size - * used in the allocation call. - */ - -void ipc_free(void* ptr, int size) -{ - if(size > PAGE_SIZE) - vfree(ptr); - else - kfree(ptr); -} - -/* - * rcu allocations: - * There are three headers that are prepended to the actual allocation: - * - during use: ipc_rcu_hdr. - * - during the rcu grace period: ipc_rcu_grace. - * - [only if vmalloc]: ipc_rcu_sched. - * Their lifetime doesn't overlap, thus the headers share the same memory. - * Unlike a normal union, they are right-aligned, thus some container_of - * forward/backward casting is necessary: + * This routine is called by sys_msgget(), sys_semget() and sys_shmget() + * when the key is not IPC_PRIVATE and that key already exists in the + * ds IDR. + * + * On success, the ipc id is returned. + * + * It is called with ipc_ids.rwsem and ipcp->lock held. */ -struct ipc_rcu_hdr +static int ipc_check_perms(struct ipc_namespace *ns, + struct kern_ipc_perm *ipcp, + const struct ipc_ops *ops, + struct ipc_params *params) { - int refcount; - int is_vmalloc; - void *data[0]; -}; - - -struct ipc_rcu_grace -{ - struct rcu_head rcu; - /* "void *" makes sure alignment of following data is sane. */ - void *data[0]; -}; - -struct ipc_rcu_sched -{ - struct work_struct work; - /* "void *" makes sure alignment of following data is sane. */ - void *data[0]; -}; - -#define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \ - sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr)) -#define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \ - sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC) + int err; + + if (ipcperms(ns, ipcp, params->flg)) + err = -EACCES; + else { + err = ops->associate(ipcp, params->flg); + if (!err) + err = ipcp->id; + } -static inline int rcu_use_vmalloc(int size) -{ - /* Too big for a single page? */ - if (HDRLEN_KMALLOC + size > PAGE_SIZE) - return 1; - return 0; + return err; } /** - * ipc_rcu_alloc - allocate ipc and rcu space - * @size: size desired + * ipcget_public - get an ipc object or create a new one + * @ns: ipc namespace + * @ids: ipc identifer set + * @ops: the actual creation routine to call + * @params: its parameters * - * Allocate memory for the rcu header structure + the object. - * Returns the pointer to the object. - * NULL is returned if the allocation fails. + * This routine is called by sys_msgget, sys_semget() and sys_shmget() + * when the key is not IPC_PRIVATE. + * It adds a new entry if the key is not found and does some permission + * / security checkings if the key is found. + * + * On success, the ipc id is returned. */ - -void* ipc_rcu_alloc(int size) +static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, + const struct ipc_ops *ops, struct ipc_params *params) { - void* out; - /* - * We prepend the allocation with the rcu struct, and - * workqueue if necessary (for vmalloc). + struct kern_ipc_perm *ipcp; + int flg = params->flg; + int err; + + /* + * Take the lock as a writer since we are potentially going to add + * a new entry + read locks are not "upgradable" */ - if (rcu_use_vmalloc(size)) { - out = vmalloc(HDRLEN_VMALLOC + size); - if (out) { - out += HDRLEN_VMALLOC; - container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1; - container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; - } + down_write(&ids->rwsem); + ipcp = ipc_findkey(ids, params->key); + if (ipcp == NULL) { + /* key not used */ + if (!(flg & IPC_CREAT)) + err = -ENOENT; + else + err = ops->getnew(ns, params); } else { - out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL); - if (out) { - out += HDRLEN_KMALLOC; - container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0; - container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; + /* ipc object has been locked by ipc_findkey() */ + + if (flg & IPC_CREAT && flg & IPC_EXCL) + err = -EEXIST; + else { + err = 0; + if (ops->more_checks) + err = ops->more_checks(ipcp, params); + if (!err) + /* + * ipc_check_perms returns the IPC id on + * success + */ + err = ipc_check_perms(ns, ipcp, ops, params); } + ipc_unlock(ipcp); } + up_write(&ids->rwsem); - return out; + return err; } -void ipc_rcu_getref(void *ptr) + +/** + * ipc_rmid - remove an ipc identifier + * @ids: ipc identifier set + * @ipcp: ipc perm structure containing the identifier to remove + * + * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held + * before this function is called, and remain locked on the exit. + */ +void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) { - container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; + int lid = ipcid_to_idx(ipcp->id); + + idr_remove(&ids->ipcs_idr, lid); + ids->in_use--; + ipcp->deleted = true; } /** - * ipc_schedule_free - free ipc + rcu space - * - * Since RCU callback function is called in bh, - * we need to defer the vfree to schedule_work + * ipc_alloc - allocate ipc space + * @size: size desired + * + * Allocate memory from the appropriate pools and return a pointer to it. + * NULL is returned if the allocation fails */ -static void ipc_schedule_free(struct rcu_head *head) +void *ipc_alloc(int size) { - struct ipc_rcu_grace *grace = - container_of(head, struct ipc_rcu_grace, rcu); - struct ipc_rcu_sched *sched = - container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]); - - INIT_WORK(&sched->work, vfree, sched); - schedule_work(&sched->work); + void *out; + if (size > PAGE_SIZE) + out = vmalloc(size); + else + out = kmalloc(size, GFP_KERNEL); + return out; } /** - * ipc_immediate_free - free ipc + rcu space + * ipc_free - free ipc space + * @ptr: pointer returned by ipc_alloc + * @size: size of block * - * Free from the RCU callback context + * Free a block created with ipc_alloc(). The caller must know the size + * used in the allocation call. + */ +void ipc_free(void *ptr, int size) +{ + if (size > PAGE_SIZE) + vfree(ptr); + else + kfree(ptr); +} + +/** + * ipc_rcu_alloc - allocate ipc and rcu space + * @size: size desired * + * Allocate memory for the rcu header structure + the object. + * Returns the pointer to the object or NULL upon failure. */ -static void ipc_immediate_free(struct rcu_head *head) +void *ipc_rcu_alloc(int size) { - struct ipc_rcu_grace *free = - container_of(head, struct ipc_rcu_grace, rcu); - kfree(free); + /* + * We prepend the allocation with the rcu struct + */ + struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size); + if (unlikely(!out)) + return NULL; + atomic_set(&out->refcount, 1); + return out + 1; } -void ipc_rcu_putref(void *ptr) +int ipc_rcu_getref(void *ptr) { - if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0) + struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; + + return atomic_inc_not_zero(&p->refcount); +} + +void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head)) +{ + struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; + + if (!atomic_dec_and_test(&p->refcount)) return; - if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) { - call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, - ipc_schedule_free); - } else { - call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, - ipc_immediate_free); - } + call_rcu(&p->rcu, func); +} + +void ipc_rcu_free(struct rcu_head *head) +{ + struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); + + if (is_vmalloc_addr(p)) + vfree(p); + else + kfree(p); } /** - * ipcperms - check IPC permissions - * @ipcp: IPC permission set - * @flag: desired permission set. + * ipcperms - check ipc permissions + * @ns: ipc namespace + * @ipcp: ipc permission set + * @flag: desired permission set + * + * Check user, group, other permissions for access + * to ipc resources. return 0 if allowed * - * Check user, group, other permissions for access - * to ipc resources. return 0 if allowed + * @flag will most probably be 0 or S_...UGO from <linux/stat.h> */ - -int ipcperms (struct kern_ipc_perm *ipcp, short flag) -{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */ +int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) +{ + kuid_t euid = current_euid(); int requested_mode, granted_mode; + audit_ipc_obj(ipcp); requested_mode = (flag >> 6) | (flag >> 3) | flag; granted_mode = ipcp->mode; - if (current->euid == ipcp->cuid || current->euid == ipcp->uid) + if (uid_eq(euid, ipcp->cuid) || + uid_eq(euid, ipcp->uid)) granted_mode >>= 6; else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) granted_mode >>= 3; /* is there some bit set in requested_mode but not in granted_mode? */ - if ((requested_mode & ~granted_mode & 0007) && - !capable(CAP_IPC_OWNER)) + if ((requested_mode & ~granted_mode & 0007) && + !ns_capable(ns->user_ns, CAP_IPC_OWNER)) return -1; return security_ipc_permission(ipcp, flag); @@ -486,36 +551,33 @@ int ipcperms (struct kern_ipc_perm *ipcp, short flag) */ /** - * kernel_to_ipc64_perm - convert kernel ipc permissions to user - * @in: kernel permissions - * @out: new style IPC permissions + * kernel_to_ipc64_perm - convert kernel ipc permissions to user + * @in: kernel permissions + * @out: new style ipc permissions * - * Turn the kernel object 'in' into a set of permissions descriptions - * for returning to userspace (out). + * Turn the kernel object @in into a set of permissions descriptions + * for returning to userspace (@out). */ - - -void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) +void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out) { out->key = in->key; - out->uid = in->uid; - out->gid = in->gid; - out->cuid = in->cuid; - out->cgid = in->cgid; + out->uid = from_kuid_munged(current_user_ns(), in->uid); + out->gid = from_kgid_munged(current_user_ns(), in->gid); + out->cuid = from_kuid_munged(current_user_ns(), in->cuid); + out->cgid = from_kgid_munged(current_user_ns(), in->cgid); out->mode = in->mode; out->seq = in->seq; } /** - * ipc64_perm_to_ipc_perm - convert old ipc permissions to new - * @in: new style IPC permissions - * @out: old style IPC permissions + * ipc64_perm_to_ipc_perm - convert new ipc permissions to old + * @in: new style ipc permissions + * @out: old style ipc permissions * - * Turn the new style permissions object in into a compatibility - * object and store it into the 'out' pointer. + * Turn the new style permissions object @in into a compatibility + * object and store it into the @out pointer. */ - -void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) +void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out) { out->key = in->key; SET_UID(out->uid, in->uid); @@ -526,94 +588,181 @@ void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) out->seq = in->seq; } -/* - * So far only shm_get_stat() calls ipc_get() via shm_get(), so ipc_get() - * is called with shm_ids.sem locked. Since grow_ary() is also called with - * shm_ids.sem down(for Shared Memory), there is no need to add read - * barriers here to gurantee the writes in grow_ary() are seen in order - * here (for Alpha). - * - * However ipc_get() itself does not necessary require ipc_ids.sem down. So - * if in the future ipc_get() is used by other places without ipc_ids.sem - * down, then ipc_get() needs read memery barriers as ipc_lock() does. +/** + * ipc_obtain_object + * @ids: ipc identifier set + * @id: ipc id to look for + * + * Look for an id in the ipc ids idr and return associated ipc object. + * + * Call inside the RCU critical section. + * The ipc object is *not* locked on exit. */ -struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id) +struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id) { - struct kern_ipc_perm* out; - int lid = id % SEQ_MULTIPLIER; - if(lid >= ids->entries->size) - return NULL; - out = ids->entries->p[lid]; + struct kern_ipc_perm *out; + int lid = ipcid_to_idx(id); + + out = idr_find(&ids->ipcs_idr, lid); + if (!out) + return ERR_PTR(-EINVAL); + return out; } -struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id) +/** + * ipc_lock - lock an ipc structure without rwsem held + * @ids: ipc identifier set + * @id: ipc id to look for + * + * Look for an id in the ipc ids idr and lock the associated ipc object. + * + * The ipc object is locked on successful exit. + */ +struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) { - struct kern_ipc_perm* out; - int lid = id % SEQ_MULTIPLIER; - struct ipc_id_ary* entries; + struct kern_ipc_perm *out; rcu_read_lock(); - entries = rcu_dereference(ids->entries); - if(lid >= entries->size) { - rcu_read_unlock(); - return NULL; - } - out = entries->p[lid]; - if(out == NULL) { - rcu_read_unlock(); - return NULL; - } + out = ipc_obtain_object(ids, id); + if (IS_ERR(out)) + goto err1; + spin_lock(&out->lock); - + /* ipc_rmid() may have already freed the ID while ipc_lock * was spinning: here verify that the structure is still valid */ - if (out->deleted) { - spin_unlock(&out->lock); - rcu_read_unlock(); - return NULL; - } + if (ipc_valid_object(out)) + return out; + + spin_unlock(&out->lock); + out = ERR_PTR(-EINVAL); +err1: + rcu_read_unlock(); return out; } -void ipc_lock_by_ptr(struct kern_ipc_perm *perm) +/** + * ipc_obtain_object_check + * @ids: ipc identifier set + * @id: ipc id to look for + * + * Similar to ipc_obtain_object() but also checks + * the ipc object reference counter. + * + * Call inside the RCU critical section. + * The ipc object is *not* locked on exit. + */ +struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id) { - rcu_read_lock(); - spin_lock(&perm->lock); + struct kern_ipc_perm *out = ipc_obtain_object(ids, id); + + if (IS_ERR(out)) + goto out; + + if (ipc_checkid(out, id)) + return ERR_PTR(-EIDRM); +out: + return out; } -void ipc_unlock(struct kern_ipc_perm* perm) +/** + * ipcget - Common sys_*get() code + * @ns: namsepace + * @ids: ipc identifier set + * @ops: operations to be called on ipc object creation, permission checks + * and further checks + * @params: the parameters needed by the previous operations. + * + * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). + */ +int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, + const struct ipc_ops *ops, struct ipc_params *params) { - spin_unlock(&perm->lock); - rcu_read_unlock(); + if (params->key == IPC_PRIVATE) + return ipcget_new(ns, ids, ops, params); + else + return ipcget_public(ns, ids, ops, params); } -int ipc_buildid(struct ipc_ids* ids, int id, int seq) +/** + * ipc_update_perm - update the permissions of an ipc object + * @in: the permission given as input. + * @out: the permission of the ipc to set. + */ +int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) { - return SEQ_MULTIPLIER*seq + id; + kuid_t uid = make_kuid(current_user_ns(), in->uid); + kgid_t gid = make_kgid(current_user_ns(), in->gid); + if (!uid_valid(uid) || !gid_valid(gid)) + return -EINVAL; + + out->uid = uid; + out->gid = gid; + out->mode = (out->mode & ~S_IRWXUGO) + | (in->mode & S_IRWXUGO); + + return 0; } -int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid) +/** + * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd + * @ns: ipc namespace + * @ids: the table of ids where to look for the ipc + * @id: the id of the ipc to retrieve + * @cmd: the cmd to check + * @perm: the permission to set + * @extra_perm: one extra permission parameter used by msq + * + * This function does some common audit and permissions check for some IPC_XXX + * cmd and is called from semctl_down, shmctl_down and msgctl_down. + * It must be called without any lock held and + * - retrieves the ipc with the given id in the given table. + * - performs some audit and permission check, depending on the given cmd + * - returns a pointer to the ipc object or otherwise, the corresponding error. + * + * Call holding the both the rwsem and the rcu read lock. + */ +struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, + struct ipc_ids *ids, int id, int cmd, + struct ipc64_perm *perm, int extra_perm) { - if(uid/SEQ_MULTIPLIER != ipcp->seq) - return 1; - return 0; + kuid_t euid; + int err = -EPERM; + struct kern_ipc_perm *ipcp; + + ipcp = ipc_obtain_object_check(ids, id); + if (IS_ERR(ipcp)) { + err = PTR_ERR(ipcp); + goto err; + } + + audit_ipc_obj(ipcp); + if (cmd == IPC_SET) + audit_ipc_set_perm(extra_perm, perm->uid, + perm->gid, perm->mode); + + euid = current_euid(); + if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || + ns_capable(ns->user_ns, CAP_SYS_ADMIN)) + return ipcp; /* successful lookup */ +err: + return ERR_PTR(err); } -#ifdef __ARCH_WANT_IPC_PARSE_VERSION +#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION /** - * ipc_parse_version - IPC call version - * @cmd: pointer to command + * ipc_parse_version - ipc call version + * @cmd: pointer to command * - * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. - * The cmd value is turned from an encoding command and version into - * just the command code. + * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. + * The @cmd value is turned from an encoding command and version into + * just the command code. */ - -int ipc_parse_version (int *cmd) +int ipc_parse_version(int *cmd) { if (*cmd & IPC_64) { *cmd ^= IPC_64; @@ -623,26 +772,39 @@ int ipc_parse_version (int *cmd) } } -#endif /* __ARCH_WANT_IPC_PARSE_VERSION */ +#endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ #ifdef CONFIG_PROC_FS -static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) +struct ipc_proc_iter { + struct ipc_namespace *ns; + struct ipc_proc_iface *iface; +}; + +/* + * This routine locks the ipc structure found at least at position pos. + */ +static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, + loff_t *new_pos) { - struct ipc_proc_iface *iface = s->private; - struct kern_ipc_perm *ipc = it; - loff_t p; + struct kern_ipc_perm *ipc; + int total, id; - /* If we had an ipc id locked before, unlock it */ - if (ipc && ipc != SEQ_START_TOKEN) - ipc_unlock(ipc); + total = 0; + for (id = 0; id < pos && total < ids->in_use; id++) { + ipc = idr_find(&ids->ipcs_idr, id); + if (ipc != NULL) + total++; + } - /* - * p = *pos - 1 (because id 0 starts at position 1) - * + 1 (because we increment the position by one) - */ - for (p = *pos; p <= iface->ids->max_id; p++) { - if ((ipc = ipc_lock(iface->ids, p)) != NULL) { - *pos = p + 1; + if (total >= ids->in_use) + return NULL; + + for (; pos < IPCMNI; pos++) { + ipc = idr_find(&ids->ipcs_idr, pos); + if (ipc != NULL) { + *new_pos = pos + 1; + rcu_read_lock(); + ipc_lock_object(ipc); return ipc; } } @@ -651,21 +813,36 @@ static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) return NULL; } +static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) +{ + struct ipc_proc_iter *iter = s->private; + struct ipc_proc_iface *iface = iter->iface; + struct kern_ipc_perm *ipc = it; + + /* If we had an ipc id locked before, unlock it */ + if (ipc && ipc != SEQ_START_TOKEN) + ipc_unlock(ipc); + + return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); +} + /* - * File positions: pos 0 -> header, pos n -> ipc id + 1. - * SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START. + * File positions: pos 0 -> header, pos n -> ipc id = n - 1. + * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. */ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) { - struct ipc_proc_iface *iface = s->private; - struct kern_ipc_perm *ipc; - loff_t p; + struct ipc_proc_iter *iter = s->private; + struct ipc_proc_iface *iface = iter->iface; + struct ipc_ids *ids; + + ids = &iter->ns->ids[iface->ids]; /* * Take the lock - this will be released by the corresponding * call to stop(). */ - down(&iface->ids->sem); + down_read(&ids->rwsem); /* pos < 0 is invalid */ if (*pos < 0) @@ -676,31 +853,29 @@ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) return SEQ_START_TOKEN; /* Find the (pos-1)th ipc */ - for (p = *pos - 1; p <= iface->ids->max_id; p++) { - if ((ipc = ipc_lock(iface->ids, p)) != NULL) { - *pos = p + 1; - return ipc; - } - } - return NULL; + return sysvipc_find_ipc(ids, *pos - 1, pos); } static void sysvipc_proc_stop(struct seq_file *s, void *it) { struct kern_ipc_perm *ipc = it; - struct ipc_proc_iface *iface = s->private; + struct ipc_proc_iter *iter = s->private; + struct ipc_proc_iface *iface = iter->iface; + struct ipc_ids *ids; - /* If we had a locked segment, release it */ + /* If we had a locked structure, release it */ if (ipc && ipc != SEQ_START_TOKEN) ipc_unlock(ipc); + ids = &iter->ns->ids[iface->ids]; /* Release the lock we took in start() */ - up(&iface->ids->sem); + up_read(&ids->rwsem); } static int sysvipc_proc_show(struct seq_file *s, void *it) { - struct ipc_proc_iface *iface = s->private; + struct ipc_proc_iter *iter = s->private; + struct ipc_proc_iface *iface = iter->iface; if (it == SEQ_START_TOKEN) return seq_puts(s, iface->header); @@ -708,29 +883,51 @@ static int sysvipc_proc_show(struct seq_file *s, void *it) return iface->show(s, it); } -static struct seq_operations sysvipc_proc_seqops = { +static const struct seq_operations sysvipc_proc_seqops = { .start = sysvipc_proc_start, .stop = sysvipc_proc_stop, .next = sysvipc_proc_next, .show = sysvipc_proc_show, }; -static int sysvipc_proc_open(struct inode *inode, struct file *file) { +static int sysvipc_proc_open(struct inode *inode, struct file *file) +{ int ret; struct seq_file *seq; + struct ipc_proc_iter *iter; + + ret = -ENOMEM; + iter = kmalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) + goto out; ret = seq_open(file, &sysvipc_proc_seqops); - if (!ret) { - seq = file->private_data; - seq->private = PDE(inode)->data; + if (ret) { + kfree(iter); + goto out; } + + seq = file->private_data; + seq->private = iter; + + iter->iface = PDE_DATA(inode); + iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); +out: return ret; } -static struct file_operations sysvipc_proc_fops = { +static int sysvipc_proc_release(struct inode *inode, struct file *file) +{ + struct seq_file *seq = file->private_data; + struct ipc_proc_iter *iter = seq->private; + put_ipc_ns(iter->ns); + return seq_release_private(inode, file); +} + +static const struct file_operations sysvipc_proc_fops = { .open = sysvipc_proc_open, .read = seq_read, .llseek = seq_lseek, - .release = seq_release, + .release = sysvipc_proc_release, }; #endif /* CONFIG_PROC_FS */ |