s390/chsc: make headers usable

Make sure that exported headers are save to be included by userspace
exploiting /dev/chsc.

Reported-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 11 insertions, 9 deletions

diff --git a/arch/s390/include/asm/chpid.h b/arch/s390/include/asm/chpid.h
index e5bde9f9291..8af0b92c90c 100644
--- a/arch/s390/include/asm/chpid.h
+++ b/arch/s390/include/asm/chpid.h
@@ -1,5 +1,5 @@
 /*
- *    Copyright IBM Corp. 2007
+ *    Copyright IBM Corp. 2007, 2012
  *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
  */
 
@@ -12,10 +12,10 @@
 #define __MAX_CHPID 255
 
 struct chp_id {
-        u8 reserved1;
-        u8 cssid;
-        u8 reserved2;
-        u8 id;
+        __u8 reserved1;
+        __u8 cssid;
+        __u8 reserved2;
+        __u8 id;
 } __attribute__((packed));
 
 #ifdef __KERNEL__
diff --git a/arch/s390/include/asm/chsc.h b/arch/s390/include/asm/chsc.h
index aea451fd182..1c6a7f85a58 100644
--- a/arch/s390/include/asm/chsc.h
+++ b/arch/s390/include/asm/chsc.h
@@ -1,7 +1,7 @@
 /*
  * ioctl interface for /dev/chsc
  *
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008, 2012
  * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
  */
 
@@ -9,9 +9,12 @@
 #define _ASM_CHSC_H
 
 #include <linux/types.h>
+#include <linux/ioctl.h>
 #include <asm/chpid.h>
 #include <asm/schid.h>
 
+#define CHSC_SIZE 0x1000
+
 struct chsc_async_header {
         __u16 length;
         __u16 code;
@@ -23,15 +26,14 @@ struct chsc_async_header {
 
 struct chsc_async_area {
         struct chsc_async_header header;
-        __u8 data[PAGE_SIZE - 16 /* size of chsc_async_header */];
+        __u8 data[CHSC_SIZE - sizeof(struct chsc_async_header)];
 } __attribute__ ((packed));
 
-
 struct chsc_response_struct {
         __u16 length;
         __u16 code;
         __u32 parms;
-        __u8 data[PAGE_SIZE - 8];
+        __u8 data[CHSC_SIZE - 2 * sizeof(__u16) - sizeof(__u32)];
 } __attribute__ ((packed));
 
 struct chsc_chp_cd {