ipc,shm: introduce shmctl_nolock

[platform/adaptation/renesas_rcar/renesas_kernel.git] / ipc / shm.c

diff --git a/ipc/shm.c b/ipc/shm.c
index c6b4ad5..3e12398 100644 (file)
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -124,6 +124,26 @@ void __init shm_init (void)
                                IPC_SHM_IDS, sysvipc_shm_proc_show);
 }
 
+static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
+{
+       struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id);
+
+       if (IS_ERR(ipcp))
+               return ERR_CAST(ipcp);
+
+       return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
+{
+       struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
+
+       if (IS_ERR(ipcp))
+               return ERR_CAST(ipcp);
+
+       return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
 /*
  * shm_lock_(check_) routines are called in the paths where the rw_mutex
  * is not necessarily held.
@@ -760,11 +780,10 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
        down_write(&shm_ids(ns).rw_mutex);
        rcu_read_lock();
 
-       ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
-                              &shmid64.shm_perm, 0);
+       ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
+                                     &shmid64.shm_perm, 0);
        if (IS_ERR(ipcp)) {
                err = PTR_ERR(ipcp);
-               /* the ipc lock is not held upon failure */
                goto out_unlock1;
        }
 
@@ -772,14 +791,16 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
 
        err = security_shm_shmctl(shp, cmd);
        if (err)
-               goto out_unlock0;
+               goto out_unlock1;
 
        switch (cmd) {
        case IPC_RMID:
+               ipc_lock_object(&shp->shm_perm);
                /* do_shm_rmid unlocks the ipc object and rcu */
                do_shm_rmid(ns, ipcp);
                goto out_up;
        case IPC_SET:
+               ipc_lock_object(&shp->shm_perm);
                err = ipc_update_perm(&shmid64.shm_perm, ipcp);
                if (err)
                        goto out_unlock0;
@@ -787,6 +808,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
                break;
        default:
                err = -EINVAL;
+               goto out_unlock1;
        }
 
 out_unlock0:
@@ -798,29 +820,24 @@ out_up:
        return err;
 }
 
-SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
+static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
+                        int cmd, int version, void __user *buf)
 {
+       int err;
        struct shmid_kernel *shp;
-       int err, version;
-       struct ipc_namespace *ns;
 
-       if (cmd < 0 || shmid < 0) {
-               err = -EINVAL;
-               goto out;
+       /* preliminary security checks for *_INFO */
+       if (cmd == IPC_INFO || cmd == SHM_INFO) {
+               err = security_shm_shmctl(NULL, cmd);
+               if (err)
+                       return err;
        }
 
-       version = ipc_parse_version(&cmd);
-       ns = current->nsproxy->ipc_ns;
-
-       switch (cmd) { /* replace with proc interface ? */
+       switch (cmd) {
        case IPC_INFO:
        {
                struct shminfo64 shminfo;
 
-               err = security_shm_shmctl(NULL, cmd);
-               if (err)
-                       return err;
-
                memset(&shminfo, 0, sizeof(shminfo));
                shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
                shminfo.shmmax = ns->shm_ctlmax;
@@ -842,10 +859,6 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
        {
                struct shm_info shm_info;
 
-               err = security_shm_shmctl(NULL, cmd);
-               if (err)
-                       return err;
-
                memset(&shm_info, 0, sizeof(shm_info));
                down_read(&shm_ids(ns).rw_mutex);
                shm_info.used_ids = shm_ids(ns).in_use;
@@ -906,6 +919,36 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
                        err = result;
                goto out;
        }
+       default:
+               return -EINVAL;
+       }
+
+out_unlock:
+       shm_unlock(shp);
+out:
+       return err;
+}
+
+SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
+{
+       struct shmid_kernel *shp;
+       int err, version;
+       struct ipc_namespace *ns;
+
+       if (cmd < 0 || shmid < 0) {
+               err = -EINVAL;
+               goto out;
+       }
+
+       version = ipc_parse_version(&cmd);
+       ns = current->nsproxy->ipc_ns;
+
+       switch (cmd) {
+       case IPC_INFO:
+       case SHM_INFO:
+       case SHM_STAT:
+       case IPC_STAT:
+               return shmctl_nolock(ns, shmid, cmd, version, buf);
        case SHM_LOCK:
        case SHM_UNLOCK:
        {