From: Tamas Koczka poprdi@google.com
[ Upstream commit 9f30de9e0343da05ac621b5817e9b1ce303c6310 ]
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: Tamas Koczka poprdi@google.com Tested-by: Aleksandr Nogikh nogikh@google.com Reviewed-by: Dmitry Vyukov dvyukov@google.com Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/bluetooth/hci_core.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 19df3905c5f8..a78f0ef7bbdc 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -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> @@ -3780,7 +3781,14 @@ 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);