[PATCH v2] Reject auths during explicit roam requests

[Ben Greear]

On 3/1/21 3:34 PM, Matthew Wang wrote:
> The roam D-Bus and wpa_cli commands flip the reassociate bit before
> calling wpa_supplicant_connect. wpa_supplicant connect eventually aborts
> ongoing scans, which causes scan results to be reported. Since the
> reassociate bit is set, this will trigger a connection attempt based on
> the aborted scan's scan results and cancel the initial connetion
> request. This often causes wpa_supplicant to reassociate to the same AP
> it is currently associated to.
> 
> Add a roam_in_progress flag to indicate that we're currently attempting
> to roam via D-Bus so that we don't initate another connection attempt.

I had similar issues, in case it helps, here is my patch:

https://github.com/greearb/hostap-ct/commit/50b1c17d0a782dc4d354ac7366500763611ea5af

I first relaxed thresholds by default, and then allowed configuring them.  When something
beyond hostapd is controlling roaming, I set the thresholds so that it would never automatically
roam based on scan results.

Lord git only knows how much of this was built on previous patches in my tree...

Thanks,
Ben


> 
> Signed-off-by: Matthew Wang <matthewmwang at chromium.org>
> Series-to: hostap at lists.infradead.org
> Series-cc: j at w1.fi, matthewmwang at chromium.org
> Change-Id: Ibeb6cceddabd10cab6938411f54ed63f4d4428c1
> ---
>   wpa_supplicant/ctrl_iface.c             | 9 +++++++++
>   wpa_supplicant/dbus/dbus_new_handlers.c | 9 +++++++++
>   wpa_supplicant/sme.c                    | 7 +++++++
>   wpa_supplicant/wpa_supplicant_i.h       | 1 +
>   4 files changed, 26 insertions(+)
> 
> diff --git a/wpa_supplicant/ctrl_iface.c b/wpa_supplicant/ctrl_iface.c
> index 0d4c2bc8f0b..048fe72d472 100644
> --- a/wpa_supplicant/ctrl_iface.c
> +++ b/wpa_supplicant/ctrl_iface.c
> @@ -5686,6 +5686,15 @@ static int wpa_supplicant_ctrl_iface_roam(struct wpa_supplicant *wpa_s,
>   	wpa_s->reassociate = 1;
>   	wpa_supplicant_connect(wpa_s, bss, ssid);
>   
> +	/*
> +	 * Indicate that an explicitly requested roam is in progress so scan
> +	 * results that come in before the 'sme-connect' radio work gets
> +	 * executed do not override the original connection attempt.
> +	 */
> +	if (radio_work_pending(wpa_s, "sme-connect")) {
> +		wpa_s->roam_in_progress = true;
> +	}
> +
>   	return 0;
>   #endif /* CONFIG_NO_SCAN_PROCESSING */
>   }
> diff --git a/wpa_supplicant/dbus/dbus_new_handlers.c b/wpa_supplicant/dbus/dbus_new_handlers.c
> index 7d20f2123a8..6803558accd 100644
> --- a/wpa_supplicant/dbus/dbus_new_handlers.c
> +++ b/wpa_supplicant/dbus/dbus_new_handlers.c
> @@ -2005,6 +2005,15 @@ DBusMessage * wpas_dbus_handler_roam(DBusMessage *message,
>   	wpa_s->reassociate = 1;
>   	wpa_supplicant_connect(wpa_s, bss, ssid);
>   
> +	/*
> +	 * Indicate that an explicitly requested roam is in progress so scan
> +	 * results that come in before the 'sme-connect' radio work gets
> +	 * executed do not override the original connection attempt.
> +	 */
> +	if (radio_work_pending(wpa_s, "sme-connect")) {
> +		wpa_s->roam_in_progress = true;
> +	}
> +
>   	return NULL;
>   #endif /* CONFIG_NO_SCAN_PROCESSING */
>   }
> diff --git a/wpa_supplicant/sme.c b/wpa_supplicant/sme.c
> index 522c8297f7e..dde80863a98 100644
> --- a/wpa_supplicant/sme.c
> +++ b/wpa_supplicant/sme.c
> @@ -941,6 +941,8 @@ static void sme_auth_start_cb(struct wpa_radio_work *work, int deinit)
>   	struct wpa_connect_work *cwork = work->ctx;
>   	struct wpa_supplicant *wpa_s = work->wpa_s;
>   
> +	wpa_s->roam_in_progress = false;
> +
>   	if (deinit) {
>   		if (work->started)
>   			wpa_s->connect_work = NULL;
> @@ -981,6 +983,11 @@ void sme_authenticate(struct wpa_supplicant *wpa_s,
>   		return;
>   	}
>   
> +	if (wpa_s->roam_in_progress) {
> +		wpa_dbg(wpa_s, MSG_DEBUG,
> +			"SME: Reject sme_authenticate() in favor of explicit roam request");
> +		return;
> +	}
>   	if (radio_work_pending(wpa_s, "sme-connect")) {
>   		/*
>   		 * The previous sme-connect work might no longer be valid due to
> diff --git a/wpa_supplicant/wpa_supplicant_i.h b/wpa_supplicant/wpa_supplicant_i.h
> index 7d14b627d89..b6c339ab711 100644
> --- a/wpa_supplicant/wpa_supplicant_i.h
> +++ b/wpa_supplicant/wpa_supplicant_i.h
> @@ -621,6 +621,7 @@ struct wpa_supplicant {
>   	u8 pending_bssid[ETH_ALEN]; /* If wpa_state == WPA_ASSOCIATING, this
>   				     * field contains the target BSSID. */
>   	int reassociate; /* reassociation requested */
> +	bool roam_in_progress; /* roam in progress */
>   	unsigned int reassoc_same_bss:1; /* reassociating to the same BSS */
>   	unsigned int reassoc_same_ess:1; /* reassociating to the same ESS */
>   	int disconnected; /* all connections disabled; i.e., do no reassociate
> 


-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com