From 72af4a843aad6afb11e014cfefcd9499b2d671e6 Mon Sep 17 00:00:00 2001
From: Bahadir Balban <bbalban@b-labs.co.uk>
Date: Sun, 18 Oct 2009 15:05:56 +0300
Subject: [PATCH] Added userptr access check to exchange_registers

---
 src/api/syscall.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/api/syscall.c b/src/api/syscall.c
index 3f78961..80ec5f8 100644
--- a/src/api/syscall.c
+++ b/src/api/syscall.c
@@ -126,6 +126,11 @@ int sys_exchange_registers(struct exregs_data *exregs, l4id_t tid)
 	int err = 0;
 	struct ktcb *task;
 
+	if ((err = check_access((unsigned long)exregs,
+				sizeof(*exregs),
+				MAP_USR_RW_FLAGS, 1)) < 0)
+		return err;
+
 	/* Find tcb from its list */
 	if (!(task = tcb_find(tid)))
 		return -ESRCH;