[PATCH 3.8 4/4] floppy: don't write kernel-only members to FDRAWCMD ioctl output

From: Kamal Mostafa
Date: Tue May 06 2014 - 17:14:49 EST


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

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

From: Matthew Daley <mattd@xxxxxxxxxxx>

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@xxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
References: CVE-2014-1738
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
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 7ca5d3d..408111f 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);
--
1.9.1

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