# Re: \[PATCH 1/2\] net: store KCOV remote handle in sk\_buff

- From: Jakub Kicinski \<kuba@kernel.org\>
- Date: 2020-10-09 23:16:40 
- List: netdev
- Page: https://ratatoskr.run/netdev/2020/10/6135710
- Thread: https://ratatoskr.run/netdev/2020/10/6132939/t.md

```text
On Wed,  7 Oct 2020 10:17:25 +0000 Aleksandr Nogikh wrote:
> From: Aleksandr Nogikh <redacted>
> 
> Remote KCOV coverage collection enables coverage-guided fuzzing of the
> code that is not reachable during normal system call execution. It is
> especially helpful for fuzzing networking subsystems, where it is
> common to perform packet handling in separate work queues even for the
> packets that originated directly from the user space.
> 
> Enable coverage-guided frame injection by adding a kcov_handle
> parameter to sk_buff structure. Initialization in __alloc_skb ensures
> that no socket buffer that was generated during a system call will be
> missed.
> 
> Code that is of interest and that performs packet processing should be
> annotated with kcov_remote_start()/kcov_remote_stop().
> 
> An alternative approach is to determine kcov_handle solely on the
> basis of the device/interface that received the specific socket
> buffer. However, in this case it would be impossible to distinguish
> between packets that originated from normal background network
> processes and those that were intentionally injected from the user
> space.
> 
> Signed-off-by: Aleksandr Nogikh <redacted>

Could you use skb_extensions for this?
```