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DPP: Fix GAS query removal race condition on DPP_STOP_LISTEN

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If a DPP_STOP_LISTEN call happens to be received when there is a pending
gas-query radio work that has not yet been started, it was possible for
gas_query_stop() to go through gas_query_done() processing with
gas->work == NULL and that ended up with the pending GAS query getting
freed without removing the pending radio work that hold a reference to
the now freed memory. Fix this by removing the pending non-started radio
work for the GAS query in this specific corner case.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
This commit is contained in:
Jouni Malinen 2018-02-07 18:03:58 +02:00 committed by Jouni Malinen
parent 27a8d93b07
commit 6a252ece24
3 changed files with 26 additions and 0 deletions
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9
wpa_supplicant/gas_query.c
View file

@ -862,6 +862,15 @@ int gas_query_stop(struct gas_query *gas, u8 dialog_token)
dl_list_for_each(query, &gas->pending, struct gas_query_pending, list) {
if (query->dialog_token == dialog_token) {
if (!gas->work) {
/* The pending radio work has not yet been
* started, but the pending entry has a
* reference to the soon to be freed query.
* Need to remove that radio work now to avoid
* leaving behind a reference to freed memory.
*/
radio_remove_pending_work(gas->wpa_s, query);
}
gas_query_done(gas, query, GAS_QUERY_STOPPED);
return 0;
}

16
wpa_supplicant/wpa_supplicant.c
View file

@ -4955,6 +4955,22 @@ void radio_remove_works(struct wpa_supplicant *wpa_s,
}
void radio_remove_pending_work(struct wpa_supplicant *wpa_s, void *ctx)
{
struct wpa_radio_work *work;
struct wpa_radio *radio = wpa_s->radio;
dl_list_for_each(work, &radio->work, struct wpa_radio_work, list) {
if (work->ctx != ctx)
continue;
wpa_dbg(wpa_s, MSG_DEBUG, "Free pending radio work '%s'@%p%s",
work->type, work, work->started ? " (started)" : "");
radio_work_free(work);
break;
}
}
static void radio_remove_interface(struct wpa_supplicant *wpa_s)
{
struct wpa_radio *radio = wpa_s->radio;

1
wpa_supplicant/wpa_supplicant_i.h
View file

@ -345,6 +345,7 @@ int radio_add_work(struct wpa_supplicant *wpa_s, unsigned int freq,
void radio_work_done(struct wpa_radio_work *work);
void radio_remove_works(struct wpa_supplicant *wpa_s,
const char *type, int remove_all);
void radio_remove_pending_work(struct wpa_supplicant *wpa_s, void *ctx);
void radio_work_check_next(struct wpa_supplicant *wpa_s);
struct wpa_radio_work *
radio_work_pending(struct wpa_supplicant *wpa_s, const char *type);