[PATCH 3.11 194/233] fs/compat: fix lookup_dcookie() parameter handling

[Luis Henriques]

3.11.10.4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heiko Carstens <heiko.carstens at de.ibm.com>

commit d8d14bd09cddbaf0168d61af638455a26bd027ff upstream.

Commit d5dc77bfeeab ("consolidate compat lookup_dcookie()") coverted all
architectures to the new compat_sys_lookup_dcookie() syscall.

The "len" paramater of the new compat syscall must have the type
compat_size_t in order to enforce zero extension for architectures where
the ABI requires that the caller of a function performed zero and/or
sign extension to 64 bit of all parameters.

Signed-off-by: Heiko Carstens <heiko.carstens at de.ibm.com>
Cc: Al Viro <viro at zeniv.linux.org.uk>
Cc: Ingo Molnar <mingo at kernel.org>
Cc: "H. Peter Anvin" <hpa at zytor.com>
Cc: Hendrik Brueckner <brueckner at linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky at de.ibm.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/dcookies.c          | 2 +-
 include/linux/compat.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/dcookies.c b/fs/dcookies.c
index ab5954b..ac44a69 100644
--- a/fs/dcookies.c
+++ b/fs/dcookies.c
@@ -204,7 +204,7 @@ out:
 }
 
 #ifdef CONFIG_COMPAT
-COMPAT_SYSCALL_DEFINE4(lookup_dcookie, u32, w0, u32, w1, char __user *, buf, size_t, len)
+COMPAT_SYSCALL_DEFINE4(lookup_dcookie, u32, w0, u32, w1, char __user *, buf, compat_size_t, len)
 {
 #ifdef __BIG_ENDIAN
 	return sys_lookup_dcookie(((u64)w0 << 32) | w1, buf, len);
diff --git a/include/linux/compat.h b/include/linux/compat.h
index caa5385..df70600 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -421,7 +421,7 @@ extern long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
 				  compat_long_t addr, compat_long_t data);
 
-asmlinkage long compat_sys_lookup_dcookie(u32, u32, char __user *, size_t);
+asmlinkage long compat_sys_lookup_dcookie(u32, u32, char __user *, compat_size_t);
 /*
  * epoll (fs/eventpoll.c) compat bits follow ...
  */
-- 
1.8.3.2