1 files changed, 127 insertions, 0 deletions
diff --git a/ipc/msgutil.c b/ipc/msgutil.c
new file mode 100644
index 000000000000..66cfb87646eb
--- /dev/null
+++ b/ipc/msgutil.c
@@ -0,0 +1,127 @@
+/*
+ * linux/ipc/util.c
+ * Copyright (C) 1999, 2004 Manfred Spraul
+ *
+ * This file is released under GNU General Public Licence version 2 or
+ * (at your option) any later version.
+ *
+ * See the file COPYING for more details.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include <linux/ipc.h>
+#include <asm/uaccess.h>
+
+#include "util.h"
+
+struct msg_msgseg {
+	struct msg_msgseg* next;
+	/* the next part of the message follows immediately */
+};
+
+#define DATALEN_MSG	(PAGE_SIZE-sizeof(struct msg_msg))
+#define DATALEN_SEG	(PAGE_SIZE-sizeof(struct msg_msgseg))
+
+struct msg_msg *load_msg(const void __user *src, int len)
+{
+	struct msg_msg *msg;
+	struct msg_msgseg **pseg;
+	int err;
+	int alen;
+
+	alen = len;
+	if (alen > DATALEN_MSG)
+		alen = DATALEN_MSG;
+
+	msg = (struct msg_msg *)kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
+	if (msg == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	msg->next = NULL;
+	msg->security = NULL;
+
+	if (copy_from_user(msg + 1, src, alen)) {
+		err = -EFAULT;
+		goto out_err;
+	}
+
+	len -= alen;
+	src = ((char __user *)src) + alen;
+	pseg = &msg->next;
+	while (len > 0) {
+		struct msg_msgseg *seg;
+		alen = len;
+		if (alen > DATALEN_SEG)
+			alen = DATALEN_SEG;
+		seg = (struct msg_msgseg *)kmalloc(sizeof(*seg) + alen,
+						 GFP_KERNEL);
+		if (seg == NULL) {
+			err = -ENOMEM;
+			goto out_err;
+		}
+		*pseg = seg;
+		seg->next = NULL;
+		if (copy_from_user(seg + 1, src, alen)) {
+			err = -EFAULT;
+			goto out_err;
+		}
+		pseg = &seg->next;
+		len -= alen;
+		src = ((char __user *)src) + alen;
+	}
+
+	err = security_msg_msg_alloc(msg);
+	if (err)
+		goto out_err;
+
+	return msg;
+
+out_err:
+	free_msg(msg);
+	return ERR_PTR(err);
+}
+
+int store_msg(void __user *dest, struct msg_msg *msg, int len)
+{
+	int alen;
+	struct msg_msgseg *seg;
+
+	alen = len;
+	if (alen > DATALEN_MSG)
+		alen = DATALEN_MSG;
+	if (copy_to_user(dest, msg + 1, alen))
+		return -1;
+
+	len -= alen;
+	dest = ((char __user *)dest) + alen;
+	seg = msg->next;
+	while (len > 0) {
+		alen = len;
+		if (alen > DATALEN_SEG)
+			alen = DATALEN_SEG;
+		if (copy_to_user(dest, seg + 1, alen))
+			return -1;
+		len -= alen;
+		dest = ((char __user *)dest) + alen;
+		seg = seg->next;
+	}
+	return 0;
+}
+
+void free_msg(struct msg_msg *msg)
+{
+	struct msg_msgseg *seg;
+
+	security_msg_msg_free(msg);
+
+	seg = msg->next;
+	kfree(msg);
+	while (seg != NULL) {
+		struct msg_msgseg *tmp = seg->next;
+		kfree(seg);
+		seg = tmp;
+	}
+}