1 files changed, 58 insertions, 134 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index cc63fae02f06..554429ade079 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -60,7 +60,6 @@ static struct vm_operations_struct shm_vm_ops;
 
 #define shm_unlock(shp)                 \
         ipc_unlock(&(shp)->shm_perm)
-#define shm_buildid(id, seq)    ipc_buildid(id, seq)
 
 static int newseg(struct ipc_namespace *, struct ipc_params *);
 static void shm_open(struct vm_area_struct *vma);
@@ -127,18 +126,6 @@ static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
         return container_of(ipcp, struct shmid_kernel, shm_perm);
 }
 
-static inline struct shmid_kernel *shm_lock_check_down(
-                                                struct ipc_namespace *ns,
-                                                int id)
-{
-        struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
-
-        if (IS_ERR(ipcp))
-                return (struct shmid_kernel *)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 held.
@@ -169,12 +156,6 @@ static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
         ipc_rmid(&shm_ids(ns), &s->shm_perm);
 }
 
-static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
-{
-        return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
-}
-
-
 
 /* This is called by fork, once for every shm attach. */
 static void shm_open(struct vm_area_struct *vma)
@@ -271,11 +252,9 @@ static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
 
         if (sfd->vm_ops->get_policy)
                 pol = sfd->vm_ops->get_policy(vma, addr);
-        else if (vma->vm_policy) {
+        else if (vma->vm_policy)
                 pol = vma->vm_policy;
-                mpol_get(pol);  /* get_vma_policy() expects this */
-        } else
-                pol = current->mempolicy;
+
         return pol;
 }
 #endif
@@ -418,7 +397,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
         if (IS_ERR(file))
                 goto no_file;
 
-        id = shm_addid(ns, shp);
+        id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
         if (id < 0) {
                 error = id;
                 goto no_id;
@@ -430,7 +409,6 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
         shp->shm_ctim = get_seconds();
         shp->shm_segsz = size;
         shp->shm_nattch = 0;
-        shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
         shp->shm_file = file;
         /*
          * shmid gets reported as "inode#" in /proc/pid/maps.
@@ -521,28 +499,14 @@ static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_
         }
 }
 
-struct shm_setbuf {
-        uid_t   uid;
-        gid_t   gid;
-        mode_t  mode;
-};      
-
-static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
+static inline unsigned long
+copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
 {
         switch(version) {
         case IPC_64:
-            {
-                struct shmid64_ds tbuf;
-
-                if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
+                if (copy_from_user(out, buf, sizeof(*out)))
                         return -EFAULT;
-
-                out->uid        = tbuf.shm_perm.uid;
-                out->gid        = tbuf.shm_perm.gid;
-                out->mode       = tbuf.shm_perm.mode;
-
                 return 0;
-            }
         case IPC_OLD:
             {
                 struct shmid_ds tbuf_old;
@@ -550,9 +514,9 @@ static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __
                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
                         return -EFAULT;
 
-                out->uid        = tbuf_old.shm_perm.uid;
-                out->gid        = tbuf_old.shm_perm.gid;
-                out->mode       = tbuf_old.shm_perm.mode;
+                out->shm_perm.uid       = tbuf_old.shm_perm.uid;
+                out->shm_perm.gid       = tbuf_old.shm_perm.gid;
+                out->shm_perm.mode      = tbuf_old.shm_perm.mode;
 
                 return 0;
             }
@@ -626,9 +590,53 @@ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
         }
 }
 
-asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
+/*
+ * This function handles some shmctl commands which require the rw_mutex
+ * to be held in write mode.
+ * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ */
+static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
+                       struct shmid_ds __user *buf, int version)
+{
+        struct kern_ipc_perm *ipcp;
+        struct shmid64_ds shmid64;
+        struct shmid_kernel *shp;
+        int err;
+
+        if (cmd == IPC_SET) {
+                if (copy_shmid_from_user(&shmid64, buf, version))
+                        return -EFAULT;
+        }
+
+        ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
+        if (IS_ERR(ipcp))
+                return PTR_ERR(ipcp);
+
+        shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+
+        err = security_shm_shmctl(shp, cmd);
+        if (err)
+                goto out_unlock;
+        switch (cmd) {
+        case IPC_RMID:
+                do_shm_rmid(ns, ipcp);
+                goto out_up;
+        case IPC_SET:
+                ipc_update_perm(&shmid64.shm_perm, ipcp);
+                shp->shm_ctim = get_seconds();
+                break;
+        default:
+                err = -EINVAL;
+        }
+out_unlock:
+        shm_unlock(shp);
+out_up:
+        up_write(&shm_ids(ns).rw_mutex);
+        return err;
+}
+
+asmlinkage long sys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
 {
-        struct shm_setbuf setbuf;
         struct shmid_kernel *shp;
         int err, version;
         struct ipc_namespace *ns;
@@ -785,97 +793,13 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
                 goto out;
         }
         case IPC_RMID:
-        {
-                /*
-                 *      We cannot simply remove the file. The SVID states
-                 *      that the block remains until the last person
-                 *      detaches from it, then is deleted. A shmat() on
-                 *      an RMID segment is legal in older Linux and if 
-                 *      we change it apps break...
-                 *
-                 *      Instead we set a destroyed flag, and then blow
-                 *      the name away when the usage hits zero.
-                 */
-                down_write(&shm_ids(ns).rw_mutex);
-                shp = shm_lock_check_down(ns, shmid);
-                if (IS_ERR(shp)) {
-                        err = PTR_ERR(shp);
-                        goto out_up;
-                }
-
-                err = audit_ipc_obj(&(shp->shm_perm));
-                if (err)
-                        goto out_unlock_up;
-
-                if (current->euid != shp->shm_perm.uid &&
-                    current->euid != shp->shm_perm.cuid && 
-                    !capable(CAP_SYS_ADMIN)) {
-                        err=-EPERM;
-                        goto out_unlock_up;
-                }
-
-                err = security_shm_shmctl(shp, cmd);
-                if (err)
-                        goto out_unlock_up;
-
-                do_shm_rmid(ns, &shp->shm_perm);
-                up_write(&shm_ids(ns).rw_mutex);
-                goto out;
-        }
-
         case IPC_SET:
-        {
-                if (!buf) {
-                        err = -EFAULT;
-                        goto out;
-                }
-
-                if (copy_shmid_from_user (&setbuf, buf, version)) {
-                        err = -EFAULT;
-                        goto out;
-                }
-                down_write(&shm_ids(ns).rw_mutex);
-                shp = shm_lock_check_down(ns, shmid);
-                if (IS_ERR(shp)) {
-                        err = PTR_ERR(shp);
-                        goto out_up;
-                }
-                err = audit_ipc_obj(&(shp->shm_perm));
-                if (err)
-                        goto out_unlock_up;
-                err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
-                if (err)
-                        goto out_unlock_up;
-                err=-EPERM;
-                if (current->euid != shp->shm_perm.uid &&
-                    current->euid != shp->shm_perm.cuid && 
-                    !capable(CAP_SYS_ADMIN)) {
-                        goto out_unlock_up;
-                }
-
-                err = security_shm_shmctl(shp, cmd);
-                if (err)
-                        goto out_unlock_up;
-                
-                shp->shm_perm.uid = setbuf.uid;
-                shp->shm_perm.gid = setbuf.gid;
-                shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
-                        | (setbuf.mode & S_IRWXUGO);
-                shp->shm_ctim = get_seconds();
-                break;
-        }
-
+                err = shmctl_down(ns, shmid, cmd, buf, version);
+                return err;
         default:
-                err = -EINVAL;
-                goto out;
+                return -EINVAL;
         }
 
-        err = 0;
-out_unlock_up:
-        shm_unlock(shp);
-out_up:
-        up_write(&shm_ids(ns).rw_mutex);
-        goto out;
 out_unlock:
         shm_unlock(shp);
 out: