Commit 9f30de9e authored by Tamas Koczka's avatar Tamas Koczka Committed by Luiz Augusto von Dentz
Browse files

Bluetooth: Collect kcov coverage from hci_rx_work 



Annotate hci_rx_work() with kcov_remote_start() and kcov_remote_stop()
calls, so remote KCOV coverage is collected while processing the rx_q
queue which is the main incoming Bluetooth packet queue.

Coverage is associated with the thread which created the packet skb.

The collected extra coverage helps kernel fuzzing efforts in finding
vulnerabilities.

This change only has effect if the kernel is compiled with CONFIG_KCOV,
otherwise kcov_ functions don't do anything.

Signed-off-by: default avatarTamas Koczka <poprdi@google.com>
Tested-by: default avatarAleksandr Nogikh <nogikh@google.com>
Reviewed-by: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
parent 68253f3c

net/bluetooth/hci_core.c

+9 −1
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/rfkill.h>

#include <linux/debugfs.h>

#include <linux/crypto.h>

#include <linux/kcov.h>

#include <linux/property.h>

#include <linux/suspend.h>

#include <linux/wait.h>
@@ -3804,7 +3805,14 @@ static void hci_rx_work(struct work_struct *work) 


	BT_DBG("%s", hdev->name);



	while ((skb = skb_dequeue(&hdev->rx_q))) {

	/* The kcov_remote functions used for collecting packet parsing

	 * coverage information from this background thread and associate

	 * the coverage with the syscall's thread which originally injected

	 * the packet. This helps fuzzing the kernel.

	 */

	for (; (skb = skb_dequeue(&hdev->rx_q)); kcov_remote_stop()) {

		kcov_remote_start_common(skb_get_kcov_handle(skb));



		/* Send copy to monitor */

		hci_send_to_monitor(hdev, skb);