netdev - Re: [Intel-wired-lan] [PATCH] [PATCH iwl-net] idpf: Acquire the lock before accessing the xn->salt

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <04affbd5-828a-4327-8b84-8767c1c139f1@intel.com>
Date: Wed, 7 Aug 2024 13:04:45 +0200
From: Alexander Lobakin <aleksander.lobakin@...el.com>
To: Manoj Vishwanathan <manojvishy@...gle.com>
CC: <netdev@...r.kernel.org>, David Decotigny <decot@...gle.com>,
	<linux-kernel@...r.kernel.org>, Tony Nguyen <anthony.l.nguyen@...el.com>,
	Przemek Kitszel <przemyslaw.kitszel@...el.com>, "David S. Miller"
	<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>,
	<intel-wired-lan@...ts.osuosl.org>
Subject: Re: [Intel-wired-lan] [PATCH] [PATCH iwl-net] idpf: Acquire the lock
 before accessing the xn->salt

From: Manoj Vishwanathan <manojvishy@...gle.com>
Date: Mon,  5 Aug 2024 18:21:59 +0000

> The transaction salt was being accessed before acquiring the
> idpf_vc_xn_lock when idpf has to forward the virtchnl reply.

You need to explain in details here what issue you have faced due to
that, how to reproduce it and how this fix does help.
Otherwise, it's impossible to suggest what is happening and how to test
whether the fix is correct.

> 
> Fixes: 34c21fa894a1a (“idpf: implement virtchnl transaction manager”)
> Signed-off-by: Manoj Vishwanathan <manojvishy@...gle.com>
> ---
>  drivers/net/ethernet/intel/idpf/idpf_virtchnl.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> index 70986e12da28..30eec674d594 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_virtchnl.c
> @@ -612,14 +612,15 @@ idpf_vc_xn_forward_reply(struct idpf_adapter *adapter,
>  		return -EINVAL;
>  	}
>  	xn = &adapter->vcxn_mngr->ring[xn_idx];
> +	idpf_vc_xn_lock(xn);
>  	salt = FIELD_GET(IDPF_VC_XN_SALT_M, msg_info);

The lock can be taken here after the FIELD_GET(), not before, to reduce
the critical/locked section execution time.

>  	if (xn->salt != salt) {
>  		dev_err_ratelimited(&adapter->pdev->dev, "Transaction salt does not match (%02x != %02x)\n",
>  				    xn->salt, salt);
> +		idpf_vc_xn_unlock(xn);
>  		return -EINVAL;
>  	}
>  
> -	idpf_vc_xn_lock(xn);
>  	switch (xn->state) {
>  	case IDPF_VC_XN_WAITING:
>  		/* success */

Thanks,
Olek