s390/compat: fix compat_sys_statfs() memory corruption

The f_spare field within struct compat_statfs is four bytes larger than within the native 31 bit struct statfs. compat_sys_statfs() clears the f_spare field in user space which means that in compat mode four bytes that are behind the user space supplied struct compat_statfs will be corrupted (zeroed). According to Thomas Gleixner's Linux 2.6 history tree this bug is present since v2.5.74 87880da "[PATCH] s390: 31 bit compat.". So it get's fixed shortly before its 10th anniversary. Tough luck. Signed-off-by: Heiko Carstens <[email protected]> Signed-off-by: Martin Schwidefsky <[email protected]>
aosmith · Apr 23, 2013 · a2aec0d · a2aec0d
1 parent 241fd9b
commit a2aec0d
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/arch/s390/include/asm/compat.h b/arch/s390/include/asm/compat.h
@@ -135,7 +135,7 @@ struct compat_statfs {
 	s32		f_namelen;
 	s32		f_frsize;
 	s32		f_flags;
-	s32		f_spare[5];
+	s32		f_spare[4];
 };
 
 #define COMPAT_RLIM_OLD_INFINITY	0x7fffffff