* 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>
*/
-#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/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>
#include "util.h"
+struct ipc_proc_iface {
+ const char *path;
+ const char *header;
+ int ids;
+ int (*show)(struct seq_file *, void *);
+};
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+
+static void ipc_memory_notifier(struct work_struct *work)
+{
+ ipcns_notify(IPCNS_MEMCHANGED);
+}
+
+static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier);
+
+
+static int ipc_memory_callback(struct notifier_block *self,
+ unsigned long action, void *arg)
+{
+ 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.
+ * No need to keep several ipc work items on the queue.
+ */
+ if (!work_pending(&ipc_memory_wq))
+ 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;
+}
+
+#endif /* CONFIG_MEMORY_HOTPLUG */
+
/**
* ipc_init - initialise IPC subsystem
*
* The various system5 IPC resources (semaphores, messages and shared
- * memory are initialised
+ * 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();
+ hotplug_memory_notifier(ipc_memory_callback, IPC_CALLBACK_PRI);
+ register_ipcns_notifier(&init_ipc_ns);
return 0;
}
__initcall(ipc_init);
/**
* ipc_init_ids - initialise IPC identifiers
* @ids: Identifier set
- * @size: Number of identifiers
*
- * 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);
+ init_rwsem(&ids->rw_mutex);
- 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)
+ 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));
+ idr_init(&ids->ipcs_idr);
+}
+
+#ifdef CONFIG_PROC_FS
+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.
+ */
+void __init ipc_init_proc_interface(const char *path, const char *header,
+ int ids, int (*show)(struct seq_file *, void *))
+{
+ struct proc_dir_entry *pde;
+ struct ipc_proc_iface *iface;
- if(ids->entries == NULL) {
- printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n");
- size = 0;
- ids->entries = &ids->nullentry;
+ iface = kmalloc(sizeof(*iface), GFP_KERNEL);
+ if (!iface)
+ return;
+ iface->path = path;
+ iface->header = header;
+ iface->ids = ids;
+ iface->show = show;
+
+ pde = proc_create_data(path,
+ S_IRUGO, /* world readable */
+ NULL, /* parent dir */
+ &sysvipc_proc_fops,
+ iface);
+ if (!pde) {
+ kfree(iface);
}
- ids->entries->size = size;
- for(i=0;i<size;i++)
- ids->entries->p[i] = NULL;
}
+#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.
+ * Requires ipc_ids.rw_mutex locked.
+ * Returns the LOCKED pointer to the ipc structure if found or NULL
+ * if not.
+ * If key is found ipc points to the owning ipc structure
*/
-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 (key == p->key)
- return id;
+
+ if (ipc->key != key) {
+ total++;
+ continue;
+ }
+
+ ipc_lock_by_ptr(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.rw_mutex 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;
- /*
- * 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);
+int ipc_get_maxid(struct ipc_ids *ids)
+{
+ struct kern_ipc_perm *ipc;
+ int max_id = -1;
+ int total, id;
+
+ 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
+ * @size: limit for the number of used ids
*
- * Add an entry 'new' to the IPC arrays. The permissions object is
+ * 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 list is returned in a locked state on success.
- * On failure the list is not locked and -1 is returned.
+ * 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 ipc_ids.rw_mutex held as a writer.
*/
int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
{
- int id;
+ uid_t euid;
+ gid_t egid;
+ int id, err;
- size = grow_ary(ids,size);
+ if (size > IPCMNI)
+ size = IPCMNI;
- /*
- * 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;
+ if (ids->in_use >= size)
+ return -ENOSPC;
+
+ spin_lock_init(&new->lock);
+ new->deleted = 0;
+ rcu_read_lock();
+ spin_lock(&new->lock);
+
+ err = idr_get_new(&ids->ipcs_idr, new, &id);
+ if (err) {
+ spin_unlock(&new->lock);
+ rcu_read_unlock();
+ return err;
}
- return -1;
-found:
+
ids->in_use++;
- if (id > ids->max_id)
- ids->max_id = id;
- new->cuid = new->uid = current->euid;
- new->gid = new->cgid = current->egid;
+ current_euid_egid(&euid, &egid);
+ new->cuid = new->uid = euid;
+ new->gid = new->cgid = egid;
new->seq = ids->seq++;
if(ids->seq > ids->seq_max)
ids->seq = 0;
- spin_lock_init(&new->lock);
- new->deleted = 0;
- rcu_read_lock();
- spin_lock(&new->lock);
- ids->entries->p[id] = new;
+ new->id = ipc_buildid(id, new->seq);
return id;
}
+/**
+ * ipcget_new - create a new ipc object
+ * @ns: namespace
+ * @ids: IPC identifer set
+ * @ops: the actual creation routine to call
+ * @params: its parameters
+ *
+ * This routine is called by sys_msgget, sys_semget() and sys_shmget()
+ * when the key is IPC_PRIVATE.
+ */
+static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
+ struct ipc_ops *ops, struct ipc_params *params)
+{
+ int err;
+retry:
+ err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
+
+ if (!err)
+ return -ENOMEM;
+
+ down_write(&ids->rw_mutex);
+ err = ops->getnew(ns, params);
+ up_write(&ids->rw_mutex);
+
+ if (err == -EAGAIN)
+ goto retry;
+
+ return err;
+}
+
+/**
+ * ipc_check_perms - check security and permissions for an IPC
+ * @ipcp: ipc permission set
+ * @ops: the actual security routine to call
+ * @params: its parameters
+ *
+ * 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
+ * ids IDR.
+ *
+ * On success, the IPC id is returned.
+ *
+ * It is called with ipc_ids.rw_mutex and ipcp->lock held.
+ */
+static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops,
+ struct ipc_params *params)
+{
+ int err;
+
+ if (ipcperms(ipcp, params->flg))
+ err = -EACCES;
+ else {
+ err = ops->associate(ipcp, params->flg);
+ if (!err)
+ err = ipcp->id;
+ }
+
+ return err;
+}
+
+/**
+ * ipcget_public - get an ipc object or create a new one
+ * @ns: namespace
+ * @ids: IPC identifer set
+ * @ops: the actual creation routine to call
+ * @params: its parameters
+ *
+ * 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.
+ */
+static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
+ struct ipc_ops *ops, struct ipc_params *params)
+{
+ struct kern_ipc_perm *ipcp;
+ int flg = params->flg;
+ int err;
+retry:
+ err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL);
+
+ /*
+ * Take the lock as a writer since we are potentially going to add
+ * a new entry + read locks are not "upgradable"
+ */
+ down_write(&ids->rw_mutex);
+ ipcp = ipc_findkey(ids, params->key);
+ if (ipcp == NULL) {
+ /* key not used */
+ if (!(flg & IPC_CREAT))
+ err = -ENOENT;
+ else if (!err)
+ err = -ENOMEM;
+ else
+ err = ops->getnew(ns, params);
+ } else {
+ /* 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(ipcp, ops, params);
+ }
+ ipc_unlock(ipcp);
+ }
+ up_write(&ids->rw_mutex);
+
+ if (err == -EAGAIN)
+ goto retry;
+
+ return err;
+}
+
+
/**
* ipc_rmid - remove an IPC identifier
- * @ids: identifier set
- * @id: Identifier to remove
+ * @ids: IPC identifier set
+ * @ipcp: ipc perm structure containing the 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.
+ * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held
+ * before this function is called, and remain locked on the exit.
*/
-struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id)
+void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
{
- struct kern_ipc_perm* p;
- int lid = id % SEQ_MULTIPLIER;
- if(lid >= ids->entries->size)
- BUG();
+ int lid = ipcid_to_idx(ipcp->id);
+
+ idr_remove(&ids->ipcs_idr, lid);
- /*
- * 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--;
- if (lid == ids->max_id) {
- do {
- lid--;
- if(lid == -1)
- break;
- } while (ids->entries->p[lid] == NULL);
- ids->max_id = lid;
- }
- p->deleted = 1;
- return p;
+ ipcp->deleted = 1;
+
+ return;
}
/**
* @ptr: pointer returned by ipc_alloc
* @size: size of block
*
- * Free a block created with ipc_alloc. The caller must know the size
+ * Free a block created with ipc_alloc(). The caller must know the size
* used in the allocation call.
*/
container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
}
+static void ipc_do_vfree(struct work_struct *work)
+{
+ vfree(container_of(work, struct ipc_rcu_sched, work));
+}
+
/**
- * ipc_schedule_free - free ipc + rcu space
+ * ipc_schedule_free - free ipc + rcu space
+ * @head: RCU callback structure for queued work
*
* Since RCU callback function is called in bh,
- * we need to defer the vfree to schedule_work
+ * we need to defer the vfree to schedule_work().
*/
static void ipc_schedule_free(struct rcu_head *head)
{
- 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]);
+ struct ipc_rcu_grace *grace;
+ struct ipc_rcu_sched *sched;
+
+ grace = container_of(head, struct ipc_rcu_grace, rcu);
+ sched = container_of(&(grace->data[0]), struct ipc_rcu_sched,
+ data[0]);
- INIT_WORK(&sched->work, vfree, sched);
+ INIT_WORK(&sched->work, ipc_do_vfree);
schedule_work(&sched->work);
}
/**
- * ipc_immediate_free - free ipc + rcu space
- *
- * Free from the RCU callback context
+ * ipc_immediate_free - free ipc + rcu space
+ * @head: RCU callback structure that contains pointer to be freed
*
+ * Free from the RCU callback context.
*/
static void ipc_immediate_free(struct rcu_head *head)
{
int ipcperms (struct kern_ipc_perm *ipcp, short flag)
{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
+ uid_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 (euid == ipcp->cuid ||
+ euid == ipcp->uid)
granted_mode >>= 6;
else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
granted_mode >>= 3;
* @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).
*/
}
/**
- * ipc64_perm_to_ipc_perm - convert old ipc permissions to new
+ * 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)
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).
+/**
+ * ipc_lock - Lock an ipc structure without rw_mutex held
+ * @ids: IPC identifier set
+ * @id: ipc id to look for
*
- * 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.
+ * Look for an id in the ipc ids idr and lock the associated ipc object.
+ *
+ * The ipc object is locked on exit.
*/
-struct kern_ipc_perm* ipc_get(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];
- return out;
-}
-struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
+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;
+ int lid = ipcid_to_idx(id);
rcu_read_lock();
- entries = rcu_dereference(ids->entries);
- if(lid >= entries->size) {
- rcu_read_unlock();
- return NULL;
- }
- out = entries->p[lid];
- if(out == NULL) {
+ out = idr_find(&ids->ipcs_idr, lid);
+ if (out == NULL) {
rcu_read_unlock();
- return NULL;
+ return ERR_PTR(-EINVAL);
}
+
spin_lock(&out->lock);
/* ipc_rmid() may have already freed the ID while ipc_lock
if (out->deleted) {
spin_unlock(&out->lock);
rcu_read_unlock();
- return NULL;
+ return ERR_PTR(-EINVAL);
}
+
return out;
}
-void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
+struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id)
{
- rcu_read_lock();
- spin_lock(&perm->lock);
+ struct kern_ipc_perm *out;
+
+ out = ipc_lock(ids, id);
+ if (IS_ERR(out))
+ return out;
+
+ if (ipc_checkid(out, id)) {
+ ipc_unlock(out);
+ return ERR_PTR(-EIDRM);
+ }
+
+ 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,
+ 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.
+ * @in: the permission given as input.
+ * @out: the permission of the ipc to set.
+ */
+void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
{
- return SEQ_MULTIPLIER*seq + id;
+ out->uid = in->uid;
+ out->gid = in->gid;
+ out->mode = (out->mode & ~S_IRWXUGO)
+ | (in->mode & S_IRWXUGO);
}
-int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid)
+/**
+ * ipcctl_pre_down - retrieve an ipc and check permissions for some IPC_XXX cmd
+ * @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 the ipc with both ipc and rw_mutex locks held in case of success
+ * or an err-code without any lock held otherwise.
+ */
+struct kern_ipc_perm *ipcctl_pre_down(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;
+ struct kern_ipc_perm *ipcp;
+ uid_t euid;
+ int err;
+
+ down_write(&ids->rw_mutex);
+ ipcp = ipc_lock_check(ids, id);
+ if (IS_ERR(ipcp)) {
+ err = PTR_ERR(ipcp);
+ goto out_up;
+ }
+
+ audit_ipc_obj(ipcp);
+ if (cmd == IPC_SET)
+ audit_ipc_set_perm(extra_perm, perm->uid,
+ perm->gid, perm->mode);
+
+ euid = current_euid();
+ if (euid == ipcp->cuid ||
+ euid == ipcp->uid || capable(CAP_SYS_ADMIN))
+ return ipcp;
+
+ err = -EPERM;
+ ipc_unlock(ipcp);
+out_up:
+ up_write(&ids->rw_mutex);
+ return ERR_PTR(err);
}
#ifdef __ARCH_WANT_IPC_PARSE_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
+ * The @cmd value is turned from an encoding command and version into
* just the command code.
*/
}
#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
+
+#ifdef CONFIG_PROC_FS
+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 kern_ipc_perm *ipc;
+ int total, id;
+
+ total = 0;
+ for (id = 0; id < pos && total < ids->in_use; id++) {
+ ipc = idr_find(&ids->ipcs_idr, id);
+ if (ipc != NULL)
+ total++;
+ }
+
+ 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;
+ ipc_lock_by_ptr(ipc);
+ return ipc;
+ }
+ }
+
+ /* Out of range - return NULL to terminate iteration */
+ 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 = 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_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_read(&ids->rw_mutex);
+
+ /* pos < 0 is invalid */
+ if (*pos < 0)
+ return NULL;
+
+ /* pos == 0 means header */
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ /* Find the (pos-1)th ipc */
+ 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_iter *iter = s->private;
+ struct ipc_proc_iface *iface = iter->iface;
+ struct ipc_ids *ids;
+
+ /* 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_read(&ids->rw_mutex);
+}
+
+static int sysvipc_proc_show(struct seq_file *s, void *it)
+{
+ 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);
+
+ return iface->show(s, it);
+}
+
+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)
+{
+ 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)
+ goto out_kfree;
+
+ seq = file->private_data;
+ seq->private = iter;
+
+ iter->iface = PDE(inode)->data;
+ iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
+out:
+ return ret;
+out_kfree:
+ kfree(iter);
+ goto out;
+}
+
+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 = sysvipc_proc_release,
+};
+#endif /* CONFIG_PROC_FS */
Code Review / linux-2.6.git / blobdiff