1 files changed, 56 insertions, 130 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index e636910454a9..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)
@@ -416,7 +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;
@@ -428,7 +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.
@@ -519,28 +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;
@@ -548,9 +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;
 	    }
@@ -624,9 +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;
@@ -783,97 +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: