[PATCH 04/06]

This patch introduces the a change to the ipc_lock() routine interface:
   . each time ipc_checkid() is called, this done after calling ipc_lock().
     So a new paramameter is added to ipc_lock(). It tells whether or not
     a ipc_checkid() is needed, and ipc_checkid() is now called from inside
     ipc_lock().


Signed-off-by: Nadia Derbey <[EMAIL PROTECTED]>


---
 ipc/msg.c  |   65 ++++++++++++++++++-------------------------
 ipc/sem.c  |   74 ++++++++++++++++++++-----------------------------
 ipc/shm.c  |   92 ++++++++++++++++++++++++++++++-------------------------------
 ipc/util.c |   16 +++++++---
 ipc/util.h |    6 ++-
 5 files changed, 121 insertions(+), 132 deletions(-)

Index: linux-2.6.21/ipc/util.c
===================================================================
--- linux-2.6.21.orig/ipc/util.c        2007-06-07 14:31:00.000000000 +0200
+++ linux-2.6.21/ipc/util.c     2007-06-07 14:57:34.000000000 +0200
@@ -667,7 +667,7 @@ void ipc64_perm_to_ipc_perm (struct ipc6
        out->seq        = in->seq;
 }
 
-struct kern_ipc_perm* ipc_lock(struct ipc_ids* ids, int id)
+struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id, int checkid)
 {
        struct kern_ipc_perm* out;
        int lid = id % SEQ_MULTIPLIER;
@@ -675,12 +675,12 @@ struct kern_ipc_perm* ipc_lock(struct ip
        rcu_read_lock();
        if (lid > ids->max_id) {
                rcu_read_unlock();
-               return NULL;
+               return ERR_PTR(-EINVAL);
        }
        out = radix_tree_lookup(&ids->id_tree, lid);
        if(out == NULL) {
                rcu_read_unlock();
-               return NULL;
+               return ERR_PTR(-EINVAL);
        }
        spin_lock(&out->lock);
        
@@ -690,8 +690,16 @@ struct kern_ipc_perm* ipc_lock(struct ip
        if (out->deleted) {
                spin_unlock(&out->lock);
                rcu_read_unlock();
-               return NULL;
+               return ERR_PTR(-EINVAL);
        }
+
+       if (checkid)
+               if (ipc_checkid(ids, out, id)) {
+                       spin_unlock(&out->lock);
+                       rcu_read_unlock();
+                       return ERR_PTR(-EIDRM);
+               }
+
        return out;
 }
 
Index: linux-2.6.21/ipc/util.h
===================================================================
--- linux-2.6.21.orig/ipc/util.h        2007-06-07 14:13:42.000000000 +0200
+++ linux-2.6.21/ipc/util.h     2007-06-07 14:57:07.000000000 +0200
@@ -12,9 +12,11 @@
 
 #define USHRT_MAX 0xffff
 #define SEQ_MULTIPLIER (IPCMNI)
-
 #define IPCS_MAX_SCAN_ENTRIES 256
 
+#define IPC_CHECKID 1
+#define NO_IPC_CHECKID 0
+
 void sem_init (void);
 void msg_init (void);
 void shm_init (void);
@@ -81,7 +83,7 @@ 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);
+struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int, int);
 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);
Index: linux-2.6.21/ipc/msg.c
===================================================================
--- linux-2.6.21.orig/ipc/msg.c 2007-06-07 14:03:15.000000000 +0200
+++ linux-2.6.21/ipc/msg.c      2007-06-07 14:40:08.000000000 +0200
@@ -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)
 
@@ -150,6 +147,12 @@ 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,
+                                               int chk)
+{
+       return (struct msg_queue *) ipc_lock(&msg_ids(ns), id, chk);
+}
+
 static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
 {
        ipc_rmid(&msg_ids(ns), &s->q_perm);
@@ -460,7 +463,7 @@ asmlinkage long sys_msgctl(int msqid, in
                        return -EFAULT;
                return (max_id < 0) ? 0 : max_id;
        }
-       case MSG_STAT:
+       case MSG_STAT:  /* msqid is an index rather than a msg queue id */
        case IPC_STAT:
        {
                struct msqid64_ds tbuf;
@@ -468,21 +471,16 @@ asmlinkage long sys_msgctl(int msqid, in
 
                if (!buf)
                        return -EFAULT;
-               if (cmd == MSG_STAT && msqid > msg_ids(ns).max_id)
-                       return -EINVAL;
-
-               memset(&tbuf, 0, sizeof(tbuf));
 
-               msq = msg_lock(ns, msqid);
-               if (msq == NULL)
-                       return -EINVAL;
-
-               if (cmd == MSG_STAT)
+               if (cmd == MSG_STAT) {
+                       msq = msg_lock(ns, msqid, NO_IPC_CHECKID);
+                       if (IS_ERR(msq) && PTR_ERR(msq) == -EINVAL)
+                               return -EINVAL;
                        success_return = msq->q_perm.id;
-               else {
-                       err = -EIDRM;
-                       if (msg_checkid(ns, msq, msqid))
-                               goto out_unlock;
+               } else {
+                       msq = msg_lock(ns, msqid, IPC_CHECKID);
+                       if (IS_ERR(msq))
+                               return PTR_ERR(msq);
                        success_return = 0;
                }
                err = -EACCES;
@@ -493,6 +491,8 @@ asmlinkage long sys_msgctl(int msqid, in
                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;
@@ -520,14 +520,12 @@ asmlinkage long sys_msgctl(int msqid, in
        }
 
        mutex_lock(&msg_ids(ns).mutex);
-       msq = msg_lock(ns, msqid);
-       err = -EINVAL;
-       if (msq == NULL)
+       msq = msg_lock(ns, msqid, IPC_CHECKID);
+       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);
@@ -670,14 +668,11 @@ long do_msgsnd(int msqid, long mtype, vo
        msg->m_type = mtype;
        msg->m_ts = msgsz;
 
-       msq = msg_lock(ns, msqid);
-       err = -EINVAL;
-       if (msq == NULL)
+       msq = msg_lock(ns, msqid, IPC_CHECKID);
+       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;
@@ -784,13 +779,9 @@ long do_msgrcv(int msqid, long *pmtype, 
        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(ns, msqid, IPC_CHECKID);
+       if (IS_ERR(msq))
+               return PTR_ERR(msq);
 
        for (;;) {
                struct msg_receiver msr_d;
Index: linux-2.6.21/ipc/sem.c
===================================================================
--- linux-2.6.21.orig/ipc/sem.c 2007-06-07 14:05:27.000000000 +0200
+++ linux-2.6.21/ipc/sem.c      2007-06-07 14:56:36.000000000 +0200
@@ -89,7 +89,6 @@
 
 #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)
@@ -188,6 +187,12 @@ 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,
+                                               int chk)
+{
+       return (struct sem_array *) ipc_lock(&sem_ids(ns), id, chk);
+}
+
 static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
 {
        ipc_rmid(&sem_ids(ns), &s->sem_perm);
@@ -620,14 +625,9 @@ static int semctl_nolock(struct ipc_name
                struct semid64_ds tbuf;
                int id;
 
-               if (semid > sem_ids(ns).max_id)
-                       return -EINVAL;
-
-               memset(&tbuf,0,sizeof(tbuf));
-
-               sma = sem_lock(ns, semid);
-               if(sma == NULL)
-                       return -EINVAL;
+               sma = sem_lock(ns, semid, NO_IPC_CHECKID);
+               if (IS_ERR(sma))
+                       return PTR_ERR(sma);
 
                err = -EACCES;
                if (ipcperms (&sma->sem_perm, S_IRUGO))
@@ -639,6 +639,8 @@ static int semctl_nolock(struct ipc_name
 
                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;
@@ -667,16 +669,12 @@ static int semctl_main(struct ipc_namesp
        ushort* sem_io = fast_sem_io;
        int nsems;
 
-       sma = sem_lock(ns, semid);
-       if(sma==NULL)
-               return -EINVAL;
+       sma = sem_lock(ns, semid, IPC_CHECKID);
+       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;
@@ -888,14 +886,10 @@ static int semctl_down(struct ipc_namesp
                if(copy_semid_from_user (&setbuf, arg.buf, version))
                        return -EFAULT;
        }
-       sma = sem_lock(ns, semid);
-       if(sma==NULL)
-               return -EINVAL;
+       sma = sem_lock(ns, semid, IPC_CHECKID);
+       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);
@@ -1079,15 +1073,10 @@ static struct sem_undo *find_undo(struct
                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(ns, semid, IPC_CHECKID);
+       if (IS_ERR(sma))
+               return ERR_PTR(PTR_ERR(sma));
+
        nsems = sma->sem_nsems;
        ipc_rcu_getref(sma);
        sem_unlock(sma);
@@ -1193,15 +1182,14 @@ retry_undos:
        } else
                un = NULL;
 
-       sma = sem_lock(ns, semid);
-       error=-EINVAL;
-       if(sma==NULL)
+       sma = sem_lock(ns, semid, IPC_CHECKID);
+       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.
         */
@@ -1266,8 +1254,8 @@ retry_undos:
                goto out_free;
        }
 
-       sma = sem_lock(ns, semid);
-       if(sma==NULL) {
+       sma = sem_lock(ns, semid, NO_IPC_CHECKID);
+       if (IS_ERR(sma)) {
                BUG_ON(queue.prev != NULL);
                error = -EIDRM;
                goto out_free;
@@ -1366,8 +1354,8 @@ void exit_sem(struct task_struct *tsk)
 
                if(semid == -1)
                        continue;
-               sma = sem_lock(ns, semid);
-               if (sma == NULL)
+               sma = sem_lock(ns, semid, NO_IPC_CHECKID);
+               if (IS_ERR(sma))
                        continue;
 
                if (u->semid == -1)
Index: linux-2.6.21/ipc/shm.c
===================================================================
--- linux-2.6.21.orig/ipc/shm.c 2007-06-07 14:09:46.000000000 +0200
+++ linux-2.6.21/ipc/shm.c      2007-06-07 14:55:28.000000000 +0200
@@ -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)       \
@@ -152,12 +150,10 @@ 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,
+                                               int chk)
 {
-       if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
-               return -EIDRM;
-       return 0;
+       return (struct shmid_kernel *) ipc_lock(&shm_ids(ns), id, chk);
 }
 
 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
@@ -179,8 +175,8 @@ static void shm_open(struct vm_area_stru
        struct shm_file_data *sfd = shm_file_data(file);
        struct shmid_kernel *shp;
 
-       shp = shm_lock(sfd->ns, sfd->id);
-       BUG_ON(!shp);
+       shp = shm_lock(sfd->ns, sfd->id, NO_IPC_CHECKID);
+       BUG_ON(IS_ERR(shp));
        shp->shm_atim = get_seconds();
        shp->shm_lprid = current->tgid;
        shp->shm_nattch++;
@@ -225,8 +221,8 @@ static void shm_close(struct vm_area_str
 
        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);
+       shp = shm_lock(ns, sfd->id, NO_IPC_CHECKID);
+       BUG_ON(IS_ERR(shp));
        shp->shm_lprid = current->tgid;
        shp->shm_dtim = get_seconds();
        shp->shm_nattch--;
@@ -673,18 +669,25 @@ asmlinkage long sys_shmctl (int shmid, i
        {
                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) {
-                       err = -EINVAL;
+               }
+
+               if (cmd == SHM_STAT) {
+                       shp = shm_lock(ns, shmid, NO_IPC_CHECKID);
+                       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(ns, shmid, IPC_CHECKID);
+                       if (IS_ERR(shp)) {
+                               err = PTR_ERR(shp);
+                               goto out;
+                       }
                        result = 0;
                }
                err=-EACCES;
@@ -693,6 +696,7 @@ asmlinkage long sys_shmctl (int shmid, i
                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;
@@ -711,14 +715,11 @@ asmlinkage long sys_shmctl (int shmid, i
        case SHM_LOCK:
        case SHM_UNLOCK:
        {
-               shp = shm_lock(ns, shmid);
-               if(shp==NULL) {
-                       err = -EINVAL;
+               shp = shm_lock(ns, shmid, IPC_CHECKID);
+               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)
@@ -768,13 +769,11 @@ asmlinkage long sys_shmctl (int shmid, i
                 *      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(ns, shmid, IPC_CHECKID);
+               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)
@@ -798,18 +797,21 @@ asmlinkage long sys_shmctl (int shmid, i
 
        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(ns, shmid, IPC_CHECKID);
+               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;
@@ -915,13 +917,11 @@ long do_shmat(int shmid, char __user *sh
         * additional creator id...
         */
        ns = current->nsproxy->ipc_ns;
-       shp = shm_lock(ns, shmid);
-       if(shp == NULL)
+       shp = shm_lock(ns, shmid, IPC_CHECKID);
+       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))
@@ -983,8 +983,8 @@ invalid:
 
 out_nattch:
        mutex_lock(&shm_ids(ns).mutex);
-       shp = shm_lock(ns, shmid);
-       BUG_ON(!shp);
+       shp = shm_lock(ns, shmid, NO_IPC_CHECKID);
+       BUG_ON(IS_ERR(shp));
        shp->shm_nattch--;
        if(shp->shm_nattch == 0 &&
           shp->shm_perm.mode & SHM_DEST)

--
-
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