[PATCH 3.12 128/182] floppy: don't write kernel-only members to FDRAWCMD ioctl output

Jiri Slaby
2014-05-13T10:30:14Z

From: Matthew Daley <mattd@bugfuzz.com>

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

===============

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: Jiri Slaby <jslaby@suse.cz>
---
drivers/block/floppy.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index b836e1a9047f..cf3e5042193c 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -3053,7 +3053,10 @@ static int raw_cmd_copyout(int cmd, void __user *param,
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);
--
1.9.3