[PATCH 5.3 39/95] ath10k: Fix a NULL-ptr-deref bug in ath10k_usb_alloc_urb_from_pipe
From: Greg Kroah-Hartman
Date: Wed Nov 27 2019 - 16:09:56 EST
From: Hui Peng <benquike@xxxxxxxxx>
commit bfd6e6e6c5d2ee43a3d9902b36e01fc7527ebb27 upstream.
The `ar_usb` field of `ath10k_usb_pipe_usb_pipe` objects
are initialized to point to the containing `ath10k_usb` object
according to endpoint descriptors read from the device side, as shown
below in `ath10k_usb_setup_pipe_resources`:
for (i = 0; i < iface_desc->desc.bNumEndpoints; ++i) {
endpoint = &iface_desc->endpoint[i].desc;
// get the address from endpoint descriptor
pipe_num = ath10k_usb_get_logical_pipe_num(ar_usb,
endpoint->bEndpointAddress,
&urbcount);
......
// select the pipe object
pipe = &ar_usb->pipes[pipe_num];
// initialize the ar_usb field
pipe->ar_usb = ar_usb;
}
The driver assumes that the addresses reported in endpoint
descriptors from device side to be complete. If a device is
malicious and does not report complete addresses, it may trigger
NULL-ptr-deref `ath10k_usb_alloc_urb_from_pipe` and
`ath10k_usb_free_urb_to_pipe`.
This patch fixes the bug by preventing potential NULL-ptr-deref.
Signed-off-by: Hui Peng <benquike@xxxxxxxxx>
Reported-by: Hui Peng <benquike@xxxxxxxxx>
Reported-by: Mathias Payer <mathias.payer@xxxxxxxxxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
[groeck: Add driver tag to subject, fix build warning]
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/wireless/ath/ath10k/usb.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/drivers/net/wireless/ath/ath10k/usb.c
+++ b/drivers/net/wireless/ath/ath10k/usb.c
@@ -38,6 +38,10 @@ ath10k_usb_alloc_urb_from_pipe(struct at
struct ath10k_urb_context *urb_context = NULL;
unsigned long flags;
+ /* bail if this pipe is not initialized */
+ if (!pipe->ar_usb)
+ return NULL;
+
spin_lock_irqsave(&pipe->ar_usb->cs_lock, flags);
if (!list_empty(&pipe->urb_list_head)) {
urb_context = list_first_entry(&pipe->urb_list_head,
@@ -55,6 +59,10 @@ static void ath10k_usb_free_urb_to_pipe(
{
unsigned long flags;
+ /* bail if this pipe is not initialized */
+ if (!pipe->ar_usb)
+ return;
+
spin_lock_irqsave(&pipe->ar_usb->cs_lock, flags);
pipe->urb_cnt++;