ipc: integrate ipc_checkid() into ipc_lock()

This patch introduces a new ipc_lock_check() routine interface:
   . each time ipc_checkid() is called, this is done after calling ipc_lock().
     ipc_checkid() is now called from inside ipc_lock_check().

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: fix RCU locking]
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/ipc/msg.c b/ipc/msg.c
index c2ee26f01055c0314a4386629946bb5ce3511055..74e67203567560b18df4605297c23ccfea3a1f9b 100644 (file)
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -73,10 +73,7 @@ static struct ipc_ids init_msg_ids;
 
 #define msg_ids(ns)    (*((ns)->ids[IPC_MSG_IDS]))
 
-#define msg_lock(ns, id)       ((struct msg_queue*)ipc_lock(&msg_ids(ns), id))
 #define msg_unlock(msq)                ipc_unlock(&(msq)->q_perm)
-#define msg_checkid(ns, msq, msgid)    \
-       ipc_checkid(&msg_ids(ns), &msq->q_perm, msgid)
 #define msg_buildid(ns, id, seq) \
        ipc_buildid(&msg_ids(ns), id, seq)
 
@@ -139,6 +136,17 @@ void __init msg_init(void)
                                IPC_MSG_IDS, sysvipc_msg_proc_show);
 }
 
+static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id)
+{
+       return (struct msg_queue *) ipc_lock(&msg_ids(ns), id);
+}
+
+static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns,
+                                               int id)
+{
+       return (struct msg_queue *) ipc_lock_check(&msg_ids(ns), id);
+}
+
 static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
 {
        ipc_rmid(&msg_ids(ns), &s->q_perm);
@@ -445,18 +453,15 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
                if (!buf)
                        return -EFAULT;
 
-               memset(&tbuf, 0, sizeof(tbuf));
-
-               msq = msg_lock(ns, msqid);
-               if (msq == NULL)
-                       return -EINVAL;
-
                if (cmd == MSG_STAT) {
+                       msq = msg_lock(ns, msqid);
+                       if (IS_ERR(msq))
+                               return PTR_ERR(msq);
                        success_return = msq->q_perm.id;
                } else {
-                       err = -EIDRM;
-                       if (msg_checkid(ns, msq, msqid))
-                               goto out_unlock;
+                       msq = msg_lock_check(ns, msqid);
+                       if (IS_ERR(msq))
+                               return PTR_ERR(msq);
                        success_return = 0;
                }
                err = -EACCES;
@@ -467,6 +472,8 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
                if (err)
                        goto out_unlock;
 
+               memset(&tbuf, 0, sizeof(tbuf));
+
                kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
                tbuf.msg_stime  = msq->q_stime;
                tbuf.msg_rtime  = msq->q_rtime;
@@ -494,14 +501,12 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
        }
 
        mutex_lock(&msg_ids(ns).mutex);
-       msq = msg_lock(ns, msqid);
-       err = -EINVAL;
-       if (msq == NULL)
+       msq = msg_lock_check(ns, msqid);
+       if (IS_ERR(msq)) {
+               err = PTR_ERR(msq);
                goto out_up;
+       }
 
-       err = -EIDRM;
-       if (msg_checkid(ns, msq, msqid))
-               goto out_unlock_up;
        ipcp = &msq->q_perm;
 
        err = audit_ipc_obj(ipcp);
@@ -644,14 +649,11 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
        msg->m_type = mtype;
        msg->m_ts = msgsz;
 
-       msq = msg_lock(ns, msqid);
-       err = -EINVAL;
-       if (msq == NULL)
+       msq = msg_lock_check(ns, msqid);
+       if (IS_ERR(msq)) {
+               err = PTR_ERR(msq);
                goto out_free;
-
-       err= -EIDRM;
-       if (msg_checkid(ns, msq, msqid))
-               goto out_unlock_free;
+       }
 
        for (;;) {
                struct msg_sender s;
@@ -758,13 +760,9 @@ long do_msgrcv(int msqid, long *pmtype, void __user *mtext,
        mode = convert_mode(&msgtyp, msgflg);
        ns = current->nsproxy->ipc_ns;
 
-       msq = msg_lock(ns, msqid);
-       if (msq == NULL)
-               return -EINVAL;
-
-       msg = ERR_PTR(-EIDRM);
-       if (msg_checkid(ns, msq, msqid))
-               goto out_unlock;
+       msq = msg_lock_check(ns, msqid);
+       if (IS_ERR(msq))
+               return PTR_ERR(msq);
 
        for (;;) {
                struct msg_receiver msr_d;

diff --git a/ipc/sem.c b/ipc/sem.c
index 6af226af0b90ea538aa4586471111d70cece3a4e..673d63da52c670261433b088c2ba18090e12a8e3 100644 (file)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -88,7 +88,6 @@
 
 #define sem_ids(ns)    (*((ns)->ids[IPC_SEM_IDS]))
 
-#define sem_lock(ns, id)       ((struct sem_array*)ipc_lock(&sem_ids(ns), id))
 #define sem_unlock(sma)                ipc_unlock(&(sma)->sem_perm)
 #define sem_checkid(ns, sma, semid)    \
        ipc_checkid(&sem_ids(ns),&sma->sem_perm,semid)
@@ -175,6 +174,17 @@ void __init sem_init (void)
                                IPC_SEM_IDS, sysvipc_sem_proc_show);
 }
 
+static inline struct sem_array *sem_lock(struct ipc_namespace *ns, int id)
+{
+       return (struct sem_array *) ipc_lock(&sem_ids(ns), id);
+}
+
+static inline struct sem_array *sem_lock_check(struct ipc_namespace *ns,
+                                               int id)
+{
+       return (struct sem_array *) ipc_lock_check(&sem_ids(ns), id);
+}
+
 static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
 {
        ipc_rmid(&sem_ids(ns), &s->sem_perm);
@@ -599,11 +609,9 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum,
                struct semid64_ds tbuf;
                int id;
 
-               memset(&tbuf,0,sizeof(tbuf));
-
                sma = sem_lock(ns, semid);
-               if(sma == NULL)
-                       return -EINVAL;
+               if (IS_ERR(sma))
+                       return PTR_ERR(sma);
 
                err = -EACCES;
                if (ipcperms (&sma->sem_perm, S_IRUGO))
@@ -615,6 +623,8 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid, int semnum,
 
                id = sma->sem_perm.id;
 
+               memset(&tbuf, 0, sizeof(tbuf));
+
                kernel_to_ipc64_perm(&sma->sem_perm, &tbuf.sem_perm);
                tbuf.sem_otime  = sma->sem_otime;
                tbuf.sem_ctime  = sma->sem_ctime;
@@ -643,16 +653,12 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
        ushort* sem_io = fast_sem_io;
        int nsems;
 
-       sma = sem_lock(ns, semid);
-       if(sma==NULL)
-               return -EINVAL;
+       sma = sem_lock_check(ns, semid);
+       if (IS_ERR(sma))
+               return PTR_ERR(sma);
 
        nsems = sma->sem_nsems;
 
-       err=-EIDRM;
-       if (sem_checkid(ns,sma,semid))
-               goto out_unlock;
-
        err = -EACCES;
        if (ipcperms (&sma->sem_perm, (cmd==SETVAL||cmd==SETALL)?S_IWUGO:S_IRUGO))
                goto out_unlock;
@@ -864,14 +870,10 @@ static int semctl_down(struct ipc_namespace *ns, int semid, int semnum,
                if(copy_semid_from_user (&setbuf, arg.buf, version))
                        return -EFAULT;
        }
-       sma = sem_lock(ns, semid);
-       if(sma==NULL)
-               return -EINVAL;
+       sma = sem_lock_check(ns, semid);
+       if (IS_ERR(sma))
+               return PTR_ERR(sma);
 
-       if (sem_checkid(ns,sma,semid)) {
-               err=-EIDRM;
-               goto out_unlock;
-       }       
        ipcp = &sma->sem_perm;
 
        err = audit_ipc_obj(ipcp);
@@ -1055,15 +1057,10 @@ static struct sem_undo *find_undo(struct ipc_namespace *ns, int semid)
                goto out;
 
        /* no undo structure around - allocate one. */
-       sma = sem_lock(ns, semid);
-       un = ERR_PTR(-EINVAL);
-       if(sma==NULL)
-               goto out;
-       un = ERR_PTR(-EIDRM);
-       if (sem_checkid(ns,sma,semid)) {
-               sem_unlock(sma);
-               goto out;
-       }
+       sma = sem_lock_check(ns, semid);
+       if (IS_ERR(sma))
+               return ERR_PTR(PTR_ERR(sma));
+
        nsems = sma->sem_nsems;
        ipc_rcu_getref(sma);
        sem_unlock(sma);
@@ -1169,15 +1166,14 @@ retry_undos:
        } else
                un = NULL;
 
-       sma = sem_lock(ns, semid);
-       error=-EINVAL;
-       if(sma==NULL)
+       sma = sem_lock_check(ns, semid);
+       if (IS_ERR(sma)) {
+               error = PTR_ERR(sma);
                goto out_free;
-       error = -EIDRM;
-       if (sem_checkid(ns,sma,semid))
-               goto out_unlock_free;
+       }
+
        /*
-        * semid identifies are not unique - find_undo may have
+        * semid identifiers are not unique - find_undo may have
         * allocated an undo structure, it was invalidated by an RMID
         * and now a new array with received the same id. Check and retry.
         */
@@ -1243,7 +1239,7 @@ retry_undos:
        }
 
        sma = sem_lock(ns, semid);
-       if(sma==NULL) {
+       if (IS_ERR(sma)) {
                BUG_ON(queue.prev != NULL);
                error = -EIDRM;
                goto out_free;
@@ -1343,7 +1339,7 @@ void exit_sem(struct task_struct *tsk)
                if(semid == -1)
                        continue;
                sma = sem_lock(ns, semid);
-               if (sma == NULL)
+               if (IS_ERR(sma))
                        continue;
 
                if (u->semid == -1)

diff --git a/ipc/shm.c b/ipc/shm.c
index 8cf1cf3d5becc6180f32ae7a8d0ea41f2878bb10..8241264941a2aa4ddae64122260506c277f83152 100644 (file)
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -59,8 +59,6 @@ static struct ipc_ids init_shm_ids;
 
 #define shm_ids(ns)    (*((ns)->ids[IPC_SHM_IDS]))
 
-#define shm_lock(ns, id)               \
-       ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
 #define shm_unlock(shp)                        \
        ipc_unlock(&(shp)->shm_perm)
 #define shm_buildid(ns, id, seq)       \
@@ -139,12 +137,15 @@ void __init shm_init (void)
                                IPC_SHM_IDS, sysvipc_shm_proc_show);
 }
 
-static inline int shm_checkid(struct ipc_namespace *ns,
-               struct shmid_kernel *s, int id)
+static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 {
-       if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
-               return -EIDRM;
-       return 0;
+       return (struct shmid_kernel *) ipc_lock(&shm_ids(ns), id);
+}
+
+static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
+                                               int id)
+{
+       return (struct shmid_kernel *) ipc_lock_check(&shm_ids(ns), id);
 }
 
 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
@@ -167,7 +168,7 @@ static void shm_open(struct vm_area_struct *vma)
        struct shmid_kernel *shp;
 
        shp = shm_lock(sfd->ns, sfd->id);
-       BUG_ON(!shp);
+       BUG_ON(IS_ERR(shp));
        shp->shm_atim = get_seconds();
        shp->shm_lprid = task_tgid_vnr(current);
        shp->shm_nattch++;
@@ -213,7 +214,7 @@ static void shm_close(struct vm_area_struct *vma)
        mutex_lock(&shm_ids(ns).mutex);
        /* remove from the list of attaches of the shm segment */
        shp = shm_lock(ns, sfd->id);
-       BUG_ON(!shp);
+       BUG_ON(IS_ERR(shp));
        shp->shm_lprid = task_tgid_vnr(current);
        shp->shm_dtim = get_seconds();
        shp->shm_nattch--;
@@ -662,17 +663,25 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
        {
                struct shmid64_ds tbuf;
                int result;
-               memset(&tbuf, 0, sizeof(tbuf));
-               shp = shm_lock(ns, shmid);
-               if(shp==NULL) {
-                       err = -EINVAL;
+
+               if (!buf) {
+                       err = -EFAULT;
                        goto out;
-               } else if (cmd == SHM_STAT) {
+               }
+
+               if (cmd == SHM_STAT) {
+                       shp = shm_lock(ns, shmid);
+                       if (IS_ERR(shp)) {
+                               err = PTR_ERR(shp);
+                               goto out;
+                       }
                        result = shp->shm_perm.id;
                } else {
-                       err = shm_checkid(ns, shp,shmid);
-                       if(err)
-                               goto out_unlock;
+                       shp = shm_lock_check(ns, shmid);
+                       if (IS_ERR(shp)) {
+                               err = PTR_ERR(shp);
+                               goto out;
+                       }
                        result = 0;
                }
                err=-EACCES;
@@ -681,6 +690,7 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
                err = security_shm_shmctl(shp, cmd);
                if (err)
                        goto out_unlock;
+               memset(&tbuf, 0, sizeof(tbuf));
                kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
                tbuf.shm_segsz  = shp->shm_segsz;
                tbuf.shm_atime  = shp->shm_atim;
@@ -699,14 +709,11 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
        case SHM_LOCK:
        case SHM_UNLOCK:
        {
-               shp = shm_lock(ns, shmid);
-               if(shp==NULL) {
-                       err = -EINVAL;
+               shp = shm_lock_check(ns, shmid);
+               if (IS_ERR(shp)) {
+                       err = PTR_ERR(shp);
                        goto out;
                }
-               err = shm_checkid(ns, shp,shmid);
-               if(err)
-                       goto out_unlock;
 
                err = audit_ipc_obj(&(shp->shm_perm));
                if (err)
@@ -756,13 +763,11 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
                 *      the name away when the usage hits zero.
                 */
                mutex_lock(&shm_ids(ns).mutex);
-               shp = shm_lock(ns, shmid);
-               err = -EINVAL;
-               if (shp == NULL) 
+               shp = shm_lock_check(ns, shmid);
+               if (IS_ERR(shp)) {
+                       err = PTR_ERR(shp);
                        goto out_up;
-               err = shm_checkid(ns, shp, shmid);
-               if(err)
-                       goto out_unlock_up;
+               }
 
                err = audit_ipc_obj(&(shp->shm_perm));
                if (err)
@@ -786,18 +791,21 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 
        case IPC_SET:
        {
+               if (!buf) {
+                       err = -EFAULT;
+                       goto out;
+               }
+
                if (copy_shmid_from_user (&setbuf, buf, version)) {
                        err = -EFAULT;
                        goto out;
                }
                mutex_lock(&shm_ids(ns).mutex);
-               shp = shm_lock(ns, shmid);
-               err=-EINVAL;
-               if(shp==NULL)
+               shp = shm_lock_check(ns, shmid);
+               if (IS_ERR(shp)) {
+                       err = PTR_ERR(shp);
                        goto out_up;
-               err = shm_checkid(ns, shp,shmid);
-               if(err)
-                       goto out_unlock_up;
+               }
                err = audit_ipc_obj(&(shp->shm_perm));
                if (err)
                        goto out_unlock_up;
@@ -903,13 +911,11 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
         * additional creator id...
         */
        ns = current->nsproxy->ipc_ns;
-       shp = shm_lock(ns, shmid);
-       if(shp == NULL)
+       shp = shm_lock_check(ns, shmid);
+       if (IS_ERR(shp)) {
+               err = PTR_ERR(shp);
                goto out;
-
-       err = shm_checkid(ns, shp,shmid);
-       if (err)
-               goto out_unlock;
+       }
 
        err = -EACCES;
        if (ipcperms(&shp->shm_perm, acc_mode))
@@ -970,7 +976,7 @@ invalid:
 out_nattch:
        mutex_lock(&shm_ids(ns).mutex);
        shp = shm_lock(ns, shmid);
-       BUG_ON(!shp);
+       BUG_ON(IS_ERR(shp));
        shp->shm_nattch--;
        if(shp->shm_nattch == 0 &&
           shp->shm_perm.mode & SHM_DEST)

diff --git a/ipc/util.c b/ipc/util.c
index e72865f677a7780df1a7d89ed07909af33da6a44..9b0c4e7753af24cd5fbd1417fc3f7ac69e40daf3 100644 (file)
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -678,7 +678,7 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
        out = idr_find(&ids->ipcs_idr, lid);
        if (out == NULL) {
                rcu_read_unlock();
-               return NULL;
+               return ERR_PTR(-EINVAL);
        }
 
        spin_lock(&out->lock);
@@ -689,36 +689,17 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
        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)
-{
-       rcu_read_lock();
-       spin_lock(&perm->lock);
-}
-
-void ipc_unlock(struct kern_ipc_perm* perm)
-{
-       spin_unlock(&perm->lock);
-       rcu_read_unlock();
-}
-
 int ipc_buildid(struct ipc_ids* ids, int id, int seq)
 {
        return SEQ_MULTIPLIER*seq + id;
 }
 
-int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid)
-{
-       if(uid/SEQ_MULTIPLIER != ipcp->seq)
-               return 1;
-       return 0;
-}
-
 #ifdef __ARCH_WANT_IPC_PARSE_VERSION
 
 

diff --git a/ipc/util.h b/ipc/util.h
index 1546eda7d99e84f3d07ec6f1b481d3fab7fae0a6..c4b0a9865bf5d991eaf1f676dc11b747c8a15776 100644 (file)
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -11,6 +11,7 @@
 #define _IPC_UTIL_H
 
 #include <linux/idr.h>
+#include <linux/err.h>
 
 #define USHRT_MAX 0xffff
 #define SEQ_MULTIPLIER (IPCMNI)
@@ -103,11 +104,8 @@ void* ipc_rcu_alloc(int size);
 void ipc_rcu_getref(void *ptr);
 void ipc_rcu_putref(void *ptr);
 
-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);
+struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
 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);
 
 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);
@@ -127,6 +125,43 @@ extern int ipcget_new(struct ipc_namespace *, struct ipc_ids *,
 extern int ipcget_public(struct ipc_namespace *, struct ipc_ids *,
                        struct ipc_ops *, struct ipc_params *);
 
+static inline int ipc_checkid(struct ipc_ids *ids, 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(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(ids, out, id)) {
+               ipc_unlock(out);
+               return ERR_PTR(-EIDRM);
+       }
+
+       return out;
+}
+
 static inline int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
                        struct ipc_ops *ops, struct ipc_params *params)
 {