Re: [PATCH mptcp-next] Squash to "DO-NOT-MERGE: mptcp: improve code coverage for CI"

[Mat Martineau <martineau@kernel.org>]

On Fri, 16 Feb 2024, Matthieu Baerts (NGI0) wrote:

> As discussed on [1], an additional check is done to catch local software
> bug.
>
> This patch is supposed to land only in our tree, for both 'export' and
> 'export-net' branches, because the warning could be triggered by bugged/
> malicious peer. We want it in our tree for our CI to detect internal
> bugs.
>
> Link: https://lore.kernel.org/all/20240215-mptcp-fix-bogus-pr-warn-v1-1-d14c10312820@kernel.org/ [1]
> Suggested-by: Paolo Abeni <pabeni@redhat.com>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

Looks good to squash. Would be good to keep some of the above info in the 
post-squash commit message for context (especially the lore link).

One other thing, I noticed that this is mentioned in the "DO-NOT-MERGE: 
mptcp: improve code coverage for CI" commit message:

"""
     mptcp: use kmalloc on kasan build

       Helps detection UaF, which apparently kasan misses with kmem_cache
       allocator.

       We also need to always set the SOCK_RCU_FREE flag, to preserved the
       current code leveraging SLAB_TYPESAFE_BY_RCU. This latter change will
       make unreachable some existing errors path, but I don't see other
       options.

"""

But it looks like the code for that disappeared between 
export/20230405T131056 and export/20230405T132954 (also missing on 
export-net). I didn't find mention of this in the mailing list. A topgit 
glitch?


- Mat

> ---
> net/mptcp/options.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/net/mptcp/options.c b/net/mptcp/options.c
> index 27ca42c77b02..5926955625cf 100644
> --- a/net/mptcp/options.c
> +++ b/net/mptcp/options.c
> @@ -982,7 +982,8 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
> 		WRITE_ONCE(msk->pm.remote_deny_join_id0, true);
>
> 	if (unlikely(!READ_ONCE(msk->pm.server_side)))
> -		pr_warn_once("bogus mpc option on established client sk");
> +		/* DO-NOT-MERGE: use WARN i/o pr_warn: only for MPTCP export */
> +		WARN_ONCE(1, "bogus mpc option on established client sk");
>
> set_fully_established:
> 	mptcp_data_lock((struct sock *)msk);
>
> ---
> base-commit: 65bda47e218b37c3dc919d3ccbd19dfad87a99e5
> change-id: 20240216-mptcp-warn-bogus-pr-warn-6dcc88038246
>
> Best regards,
> -- 
> Matthieu Baerts (NGI0) <matttbe@kernel.org>
>
>
>