Bluetooth: RFCOMM - Fix info leak in ioctl(RFCOMMGETDEVLIST)

[ Upstream commit f9432c5ec8b1e9a09b9b0e5569e3c73db8de432a ]

The RFCOMM code fails to initialize the two padding bytes of struct
rfcomm_dev_list_req inserted for alignment before copying it to
userland. Additionally there are two padding bytes in each instance of
struct rfcomm_dev_info. The ioctl() that for disclosures two bytes plus
dev_num times two bytes uninitialized kernel heap memory.

Allocate the memory using kzalloc() to fix this issue.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index c258796..bc1eb56 100644 (file)
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -471,7 +471,7 @@ static int rfcomm_get_dev_list(void __user *arg)
 
        size = sizeof(*dl) + dev_num * sizeof(*di);
 
-       dl = kmalloc(size, GFP_KERNEL);
+       dl = kzalloc(size, GFP_KERNEL);
        if (!dl)
                return -ENOMEM;