x86, tls: Off by one limit check

These are used as offsets into an array of GDT_ENTRY_TLS_ENTRIES members
so GDT_ENTRY_TLS_ENTRIES is one past the end of the array.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: http://lkml.kernel.org/r/20120324075250.GA28258@elgon.mountain
Cc: <stable@vger.kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/tls.c

@@ -163,7 +163,7 @@ int regset_tls_get(struct task_struct *target, const struct user_regset *regset,
 {
 	const struct desc_struct *tls;
 
-	if (pos > GDT_ENTRY_TLS_ENTRIES * sizeof(struct user_desc) ||
+	if (pos >= GDT_ENTRY_TLS_ENTRIES * sizeof(struct user_desc) ||
 	    (pos % sizeof(struct user_desc)) != 0 ||
 	    (count % sizeof(struct user_desc)) != 0)
 		return -EINVAL;
@@ -198,7 +198,7 @@ int regset_tls_set(struct task_struct *target, const struct user_regset *regset,
 	struct user_desc infobuf[GDT_ENTRY_TLS_ENTRIES];
 	const struct user_desc *info;
 
-	if (pos > GDT_ENTRY_TLS_ENTRIES * sizeof(struct user_desc) ||
+	if (pos >= GDT_ENTRY_TLS_ENTRIES * sizeof(struct user_desc) ||
 	    (pos % sizeof(struct user_desc)) != 0 ||
 	    (count % sizeof(struct user_desc)) != 0)
 		return -EINVAL;