[1/1] ath6kl: fix a NULL-ptr-deref bug in ath6kl_usb_alloc_urb_from_pipe()
diff mbox series

Message ID 20191003154727.14199-2-tyhicks@canonical.com
State New
Headers show
Series
  • CVE-2019-15098: Atheros ath6kl DoS
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Commit Message

Tyler Hicks Oct. 3, 2019, 3:47 p.m. UTC
From: Hui Peng <benquike@gmail.com>

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>

CVE-2019-15098

(cherry picked from commit 39d170b3cb62ba98567f5c4f40c27b5864b304e5)
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
---
 drivers/net/wireless/ath/ath6kl/usb.c | 8 ++++++++
 1 file changed, 8 insertions(+)

Comments

Connor Kuehl Oct. 3, 2019, 8:39 p.m. UTC | #1
On 10/3/19 8:47 AM, Tyler Hicks wrote:
> From: Hui Peng <benquike@gmail.com>
> 
> 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>
> 
> CVE-2019-15098
> 
> (cherry picked from commit 39d170b3cb62ba98567f5c4f40c27b5864b304e5)
> Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

Clean cherry pick. Patch description features a nice walkthrough, too.

Acked-by: Connor Kuehl <connor.kuehl@canonical.com>

> ---
>   drivers/net/wireless/ath/ath6kl/usb.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/net/wireless/ath/ath6kl/usb.c b/drivers/net/wireless/ath/ath6kl/usb.c
> index 4defb7a0330f..53b66e9434c9 100644
> --- 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 ath6kl_usb_pipe *pipe)
>   	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(struct ath6kl_usb_pipe *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++;
>   
>

Patch
diff mbox series

diff --git a/drivers/net/wireless/ath/ath6kl/usb.c b/drivers/net/wireless/ath/ath6kl/usb.c
index 4defb7a0330f..53b66e9434c9 100644
--- 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 ath6kl_usb_pipe *pipe)
 	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(struct ath6kl_usb_pipe *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++;