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Interworking: Avoid busy loop in scan result mismatch corner cases

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It was possible for interworking_find_network_match() to find a possible
BSS match in a case where more thorough checks in
wpa_supplicant_select_bss() reject network. This itself is fine, in
general, but when combined with wpa_supplicant_fast_associate()
optimization and auto_interworking=1, this resulted in a busy loop of up
to five seconds and a possible stack overflow due to recursion in that
loop.

Fix this by limiting the Interworking wpa_supplicant_fast_associate()
call to be used only once per scan iteration, so that new scan
operations can be completed before going through the scan results again.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2015-01-17 01:43:00 +02:00
parent edd5939a26
commit a8826b1848
3 changed files with 10 additions and 1 deletions
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7
wpa_supplicant/interworking.c
View file

@ -73,6 +73,8 @@ static int cred_prio_cmp(const struct wpa_cred *a, const struct wpa_cred *b)
static void interworking_reconnect(struct wpa_supplicant *wpa_s)
{
unsigned int tried;
if (wpa_s->wpa_state >= WPA_AUTHENTICATING) {
wpa_supplicant_cancel_sched_scan(wpa_s);
wpa_supplicant_deauthenticate(wpa_s,
@ -80,10 +82,13 @@ static void interworking_reconnect(struct wpa_supplicant *wpa_s)
}
wpa_s->disconnected = 0;
wpa_s->reassociate = 1;
tried = wpa_s->interworking_fast_assoc_tried;
wpa_s->interworking_fast_assoc_tried = 1;
if (wpa_supplicant_fast_associate(wpa_s) >= 0)
if (!tried && wpa_supplicant_fast_associate(wpa_s) >= 0)
return;
wpa_s->interworking_fast_assoc_tried = 0;
wpa_supplicant_req_scan(wpa_s, 0, 0);
}

3
wpa_supplicant/scan.c
View file

@ -1002,6 +1002,9 @@ scan:
wpa_supplicant_req_scan(wpa_s, 1, 0);
} else {
wpa_s->scan_for_connection = 0;
#ifdef CONFIG_INTERWORKING
wpa_s->interworking_fast_assoc_tried = 0;
#endif /* CONFIG_INTERWORKING */
}
}

1
wpa_supplicant/wpa_supplicant_i.h
View file

@ -857,6 +857,7 @@ struct wpa_supplicant {
unsigned int network_select:1;
unsigned int auto_select:1;
unsigned int auto_network_select:1;
unsigned int interworking_fast_assoc_tried:1;
unsigned int fetch_all_anqp:1;
unsigned int fetch_osu_info:1;
unsigned int fetch_osu_waiting_scan:1;