3.16.77-rc1 review patch. If anyone has any objections, please let me know.
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From: Hui Peng benquike@gmail.com
commit 39d170b3cb62ba98567f5c4f40c27b5864b304e5 upstream.
The `ar_usb` field of `ath6kl_usb_pipe_usb_pipe` objects are initialized to point to the containing `ath6kl_usb` object according to endpoint descriptors read from the device side, as shown below in `ath6kl_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 = ath6kl_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 `ath6kl_usb_alloc_urb_from_pipe` and `ath6kl_usb_free_urb_to_pipe`.
This patch fixes the bug by preventing potential NULL-ptr-deref (CVE-2019-15098).
Signed-off-by: Hui Peng benquike@gmail.com Reported-by: Hui Peng benquike@gmail.com Reported-by: Mathias Payer mathias.payer@nebelwelt.net Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Kalle Valo kvalo@codeaurora.org Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/net/wireless/ath/ath6kl/usb.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/drivers/net/wireless/ath/ath6kl/usb.c +++ b/drivers/net/wireless/ath/ath6kl/usb.c @@ -132,6 +132,10 @@ ath6kl_usb_alloc_urb_from_pipe(struct at struct ath6kl_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 = @@ -150,6 +154,10 @@ static void ath6kl_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++;