[PATCH 3.2 34/34] [2/2] floppy: don't write kernel-only members to FDRAWCMD ioctl output

[Ben Hutchings <ben@decadent.org.uk>]

3.2.59-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Matthew Daley <mattd@bugfuzz.com>

commit 2145e15e0557a01b9195d1c7199a1b92cb9be81f upstream.

Do not leak kernel-only floppy_raw_cmd structure members to userspace.
This includes the linked-list pointer and the pointer to the allocated
DMA space.

Signed-off-by: Matthew Daley <mattd@bugfuzz.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/block/floppy.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -3060,7 +3060,10 @@ static int raw_cmd_copyout(int cmd, void
 	int ret;
 
 	while (ptr) {
-		ret = copy_to_user(param, ptr, sizeof(*ptr));
+		struct floppy_raw_cmd cmd = *ptr;
+		cmd.next = NULL;
+		cmd.kernel_data = NULL;
+		ret = copy_to_user(param, &cmd, sizeof(cmd));
 		if (ret)
 			return -EFAULT;
 		param += sizeof(struct floppy_raw_cmd);