1 files changed, 135 insertions, 33 deletions

diff --git a/ipc/util.h b/ipc/util.h
index 333e891bcaca..9ffea40457ce 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -10,6 +10,9 @@
 #ifndef _IPC_UTIL_H
 #define _IPC_UTIL_H
 
+#include <linux/idr.h>
+#include <linux/err.h>
+
 #define USHRT_MAX 0xffff
 #define SEQ_MULTIPLIER  (IPCMNI)
 
@@ -25,24 +28,46 @@ void sem_exit_ns(struct ipc_namespace *ns);
 void msg_exit_ns(struct ipc_namespace *ns);
 void shm_exit_ns(struct ipc_namespace *ns);
 
-struct ipc_id_ary {
-        int size;
-        struct kern_ipc_perm *p[0];
-};
-
 struct ipc_ids {
         int in_use;
-        int max_id;
         unsigned short seq;
         unsigned short seq_max;
-        struct mutex mutex;
-        struct ipc_id_ary nullentry;
-        struct ipc_id_ary* entries;
+        struct rw_semaphore rw_mutex;
+        struct idr ipcs_idr;
+};
+
+/*
+ * Structure that holds the parameters needed by the ipc operations
+ * (see after)
+ */
+struct ipc_params {
+        key_t key;
+        int flg;
+        union {
+                size_t size;    /* for shared memories */
+                int nsems;      /* for semaphores */
+        } u;                    /* holds the getnew() specific param */
+};
+
+/*
+ * Structure that holds some ipc operations. This structure is used to unify
+ * the calls to sys_msgget(), sys_semget(), sys_shmget()
+ *      . routine to call to create a new ipc object. Can be one of newque,
+ *        newary, newseg
+ *      . routine to call to check permissions for a new ipc object.
+ *        Can be one of security_msg_associate, security_sem_associate,
+ *        security_shm_associate
+ *      . 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 *);
 };
 
 struct seq_file;
 
-void ipc_init_ids(struct ipc_ids *ids, int size);
+void ipc_init_ids(struct ipc_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 *));
@@ -54,14 +79,19 @@ void __init ipc_init_proc_interface(const char *path, const char *header,
 #define IPC_MSG_IDS     1
 #define IPC_SHM_IDS     2
 
-/* must be called with ids->mutex acquired.*/
-int ipc_findkey(struct ipc_ids* ids, key_t key);
-int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size);
+#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
+
+/* must be called with ids->rw_mutex 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. */
-struct kern_ipc_perm* ipc_rmid(struct ipc_ids* ids, int id);
+void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *);
 
-int ipcperms (struct kern_ipc_perm *ipcp, short flg);
+/* must be called with ipcp locked */
+int ipcperms(struct kern_ipc_perm *ipcp, short flg);
 
 /* for rare, potentially huge allocations.
  * both function can sleep
@@ -79,24 +109,12 @@ void* ipc_rcu_alloc(int size);
 void ipc_rcu_getref(void *ptr);
 void ipc_rcu_putref(void *ptr);
 
-static inline void __ipc_fini_ids(struct ipc_ids *ids,
-                struct ipc_id_ary *entries)
-{
-        if (entries != &ids->nullentry)
-                ipc_rcu_putref(entries);
-}
-
-static inline void ipc_fini_ids(struct ipc_ids *ids)
-{
-        __ipc_fini_ids(ids, ids->entries);
-}
-
-struct kern_ipc_perm* ipc_get(struct ipc_ids* ids, int id);
-struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id);
-void ipc_lock_by_ptr(struct kern_ipc_perm *ipcp);
-void ipc_unlock(struct kern_ipc_perm* perm);
-int ipc_buildid(struct ipc_ids* ids, int id, int seq);
-int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid);
+/*
+ * ipc_lock_down: called with rw_mutex held
+ * ipc_lock: called without that lock held
+ */
+struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *, int);
+struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
 
 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);
@@ -111,5 +129,89 @@ int ipc_parse_version (int *cmd);
 extern void free_msg(struct msg_msg *msg);
 extern struct msg_msg *load_msg(const void __user *src, int len);
 extern int store_msg(void __user *dest, struct msg_msg *msg, int len);
+extern int ipcget_new(struct ipc_namespace *, struct ipc_ids *,
+                        struct ipc_ops *, struct ipc_params *);
+extern int ipcget_public(struct ipc_namespace *, struct ipc_ids *,
+                        struct ipc_ops *, struct ipc_params *);
+
+static inline int ipc_buildid(int id, int seq)
+{
+        return SEQ_MULTIPLIER * seq + id;
+}
+
+/*
+ * Must be called with ipcp locked
+ */
+static inline int ipc_checkid(struct kern_ipc_perm *ipcp, int uid)
+{
+        if (uid / SEQ_MULTIPLIER != ipcp->seq)
+                return 1;
+        return 0;
+}
+
+static inline void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
+{
+        rcu_read_lock();
+        spin_lock(&perm->lock);
+}
+
+static inline void ipc_unlock(struct kern_ipc_perm *perm)
+{
+        spin_unlock(&perm->lock);
+        rcu_read_unlock();
+}
+
+static inline struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids,
+                                                int id)
+{
+        struct kern_ipc_perm *out;
+
+        out = ipc_lock_down(ids, id);
+        if (IS_ERR(out))
+                return out;
+
+        if (ipc_checkid(out, id)) {
+                ipc_unlock(out);
+                return ERR_PTR(-EIDRM);
+        }
+
+        return out;
+}
+
+static inline struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids,
+                                                int id)
+{
+        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;
+}
+
+/**
+ * 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().
+ */
+static inline int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
+                        struct ipc_ops *ops, struct ipc_params *params)
+{
+        if (params->key == IPC_PRIVATE)
+                return ipcget_new(ns, ids, ops, params);
+        else
+                return ipcget_public(ns, ids, ops, params);
+}
 
 #endif