wps_registrar.c

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#include "includes.h"

#include "common.h"
#include "sha256.h"
#include "base64.h"
#include "ieee802_11_defs.h"
#include "eloop.h"
#include "wps_i.h"
#include "wps_dev_attr.h"
#include "wps_upnp.h"
#include "crypto.h"
#include "uuid.h"

#define WPS_WORKAROUNDS

struct wps_uuid_pin {
        struct wps_uuid_pin *next;
        u8 uuid[WPS_UUID_LEN];
        int wildcard_uuid;
        u8 *pin;
        size_t pin_len;
#define PIN_LOCKED BIT(0)
#define PIN_EXPIRES BIT(1)
        int flags;
        struct os_time expiration;
};


static void wps_free_pin(struct wps_uuid_pin *pin)
{
        os_free(pin->pin);
        os_free(pin);
}


static void wps_free_pins(struct wps_uuid_pin *pins)
{
        struct wps_uuid_pin *pin, *prev;

        pin = pins;
        while (pin) {
                prev = pin;
                pin = pin->next;
                wps_free_pin(prev);
        }
}


struct wps_pbc_session {
        struct wps_pbc_session *next;
        u8 addr[ETH_ALEN];
        u8 uuid_e[WPS_UUID_LEN];
        struct os_time timestamp;
};


static void wps_free_pbc_sessions(struct wps_pbc_session *pbc)
{
        struct wps_pbc_session *prev;

        while (pbc) {
                prev = pbc;
                pbc = pbc->next;
                os_free(prev);
        }
}


struct wps_registrar_device {
        struct wps_registrar_device *next;
        struct wps_device_data dev;
        u8 uuid[WPS_UUID_LEN];
};


struct wps_registrar {
        struct wps_context *wps;

        int pbc;
        int selected_registrar;

        int (*new_psk_cb)(void *ctx, const u8 *mac_addr, const u8 *psk,
                          size_t psk_len);
        int (*set_ie_cb)(void *ctx, const u8 *beacon_ie, size_t beacon_ie_len,
                         const u8 *probe_resp_ie, size_t probe_resp_ie_len);
        void (*pin_needed_cb)(void *ctx, const u8 *uuid_e,
                              const struct wps_device_data *dev);
        void (*reg_success_cb)(void *ctx, const u8 *mac_addr,
                               const u8 *uuid_e);
        void (*set_sel_reg_cb)(void *ctx, int sel_reg, u16 dev_passwd_id,
                               u16 sel_reg_config_methods);
        void *cb_ctx;

        struct wps_uuid_pin *pins;
        struct wps_pbc_session *pbc_sessions;

        int skip_cred_build;
        struct wpabuf *extra_cred;
        int disable_auto_conf;
        int sel_reg_dev_password_id_override;
        int sel_reg_config_methods_override;
        int static_wep_only;

        struct wps_registrar_device *devices;

        int force_pbc_overlap;
};


static int wps_set_ie(struct wps_registrar *reg);
static void wps_cb_set_sel_reg(struct wps_registrar *reg);
static void wps_registrar_pbc_timeout(void *eloop_ctx, void *timeout_ctx);
static void wps_registrar_set_selected_timeout(void *eloop_ctx,
                                               void *timeout_ctx);


static void wps_free_devices(struct wps_registrar_device *dev)
{
        struct wps_registrar_device *prev;

        while (dev) {
                prev = dev;
                dev = dev->next;
                wps_device_data_free(&prev->dev);
                os_free(prev);
        }
}


static struct wps_registrar_device * wps_device_get(struct wps_registrar *reg,
                                                    const u8 *addr)
{
        struct wps_registrar_device *dev;

        for (dev = reg->devices; dev; dev = dev->next) {
                if (os_memcmp(dev->dev.mac_addr, addr, ETH_ALEN) == 0)
                        return dev;
        }
        return NULL;
}


static void wps_device_clone_data(struct wps_device_data *dst,
                                  struct wps_device_data *src)
{
        os_memcpy(dst->mac_addr, src->mac_addr, ETH_ALEN);
        dst->categ = src->categ;
        dst->oui = src->oui;
        dst->sub_categ = src->sub_categ;

#define WPS_STRDUP(n) \
        os_free(dst->n); \
        dst->n = src->n ? os_strdup(src->n) : NULL

        WPS_STRDUP(device_name);
        WPS_STRDUP(manufacturer);
        WPS_STRDUP(model_name);
        WPS_STRDUP(model_number);
        WPS_STRDUP(serial_number);
#undef WPS_STRDUP
}


int wps_device_store(struct wps_registrar *reg,
                     struct wps_device_data *dev, const u8 *uuid)
{
        struct wps_registrar_device *d;

        d = wps_device_get(reg, dev->mac_addr);
        if (d == NULL) {
                d = os_zalloc(sizeof(*d));
                if (d == NULL)
                        return -1;
                d->next = reg->devices;
                reg->devices = d;
        }

        wps_device_clone_data(&d->dev, dev);
        os_memcpy(d->uuid, uuid, WPS_UUID_LEN);

        return 0;
}


static void wps_registrar_add_pbc_session(struct wps_registrar *reg,
                                          const u8 *addr, const u8 *uuid_e)
{
        struct wps_pbc_session *pbc, *prev = NULL;
        struct os_time now;

        os_get_time(&now);

        pbc = reg->pbc_sessions;
        while (pbc) {
                if (os_memcmp(pbc->addr, addr, ETH_ALEN) == 0 &&
                    os_memcmp(pbc->uuid_e, uuid_e, WPS_UUID_LEN) == 0) {
                        if (prev)
                                prev->next = pbc->next;
                        else
                                reg->pbc_sessions = pbc->next;
                        break;
                }
                prev = pbc;
                pbc = pbc->next;
        }

        if (!pbc) {
                pbc = os_zalloc(sizeof(*pbc));
                if (pbc == NULL)
                        return;
                os_memcpy(pbc->addr, addr, ETH_ALEN);
                if (uuid_e)
                        os_memcpy(pbc->uuid_e, uuid_e, WPS_UUID_LEN);
        }

        pbc->next = reg->pbc_sessions;
        reg->pbc_sessions = pbc;
        pbc->timestamp = now;

        /* remove entries that have timed out */
        prev = pbc;
        pbc = pbc->next;

        while (pbc) {
                if (now.sec > pbc->timestamp.sec + WPS_PBC_WALK_TIME) {
                        prev->next = NULL;
                        wps_free_pbc_sessions(pbc);
                        break;
                }
                prev = pbc;
                pbc = pbc->next;
        }
}


static void wps_registrar_remove_pbc_session(struct wps_registrar *reg,
                                             const u8 *addr, const u8 *uuid_e)
{
        struct wps_pbc_session *pbc, *prev = NULL;

        pbc = reg->pbc_sessions;
        while (pbc) {
                if (os_memcmp(pbc->addr, addr, ETH_ALEN) == 0 &&
                    os_memcmp(pbc->uuid_e, uuid_e, WPS_UUID_LEN) == 0) {
                        if (prev)
                                prev->next = pbc->next;
                        else
                                reg->pbc_sessions = pbc->next;
                        os_free(pbc);
                        break;
                }
                prev = pbc;
                pbc = pbc->next;
        }
}


static int wps_registrar_pbc_overlap(struct wps_registrar *reg,
                                     const u8 *addr, const u8 *uuid_e)
{
        int count = 0;
        struct wps_pbc_session *pbc;
        struct os_time now;

        os_get_time(&now);

        for (pbc = reg->pbc_sessions; pbc; pbc = pbc->next) {
                if (now.sec > pbc->timestamp.sec + WPS_PBC_WALK_TIME)
                        break;
                if (addr == NULL || os_memcmp(addr, pbc->addr, ETH_ALEN) ||
                    uuid_e == NULL ||
                    os_memcmp(uuid_e, pbc->uuid_e, WPS_UUID_LEN))
                        count++;
        }

        if (addr || uuid_e)
                count++;

        return count > 1 ? 1 : 0;
}


static int wps_build_wps_state(struct wps_context *wps, struct wpabuf *msg)
{
        wpa_printf(MSG_DEBUG, "WPS:  * Wi-Fi Protected Setup State (%d)",
                   wps->wps_state);
        wpabuf_put_be16(msg, ATTR_WPS_STATE);
        wpabuf_put_be16(msg, 1);
        wpabuf_put_u8(msg, wps->wps_state);
        return 0;
}


#ifdef CONFIG_WPS_UPNP
static void wps_registrar_free_pending_m2(struct wps_context *wps)
{
        struct upnp_pending_message *p, *p2, *prev = NULL;
        p = wps->upnp_msgs;
        while (p) {
                if (p->type == WPS_M2 || p->type == WPS_M2D) {
                        if (prev == NULL)
                                wps->upnp_msgs = p->next;
                        else
                                prev->next = p->next;
                        wpa_printf(MSG_DEBUG, "WPS UPnP: Drop pending M2/M2D");
                        p2 = p;
                        p = p->next;
                        wpabuf_free(p2->msg);
                        os_free(p2);
                        continue;
                }
                prev = p;
                p = p->next;
        }
}
#endif /* CONFIG_WPS_UPNP */


static int wps_build_ap_setup_locked(struct wps_context *wps,
                                     struct wpabuf *msg)
{
        if (wps->ap_setup_locked) {
                wpa_printf(MSG_DEBUG, "WPS:  * AP Setup Locked");
                wpabuf_put_be16(msg, ATTR_AP_SETUP_LOCKED);
                wpabuf_put_be16(msg, 1);
                wpabuf_put_u8(msg, 1);
        }
        return 0;
}


static int wps_build_selected_registrar(struct wps_registrar *reg,
                                        struct wpabuf *msg)
{
        if (!reg->selected_registrar)
                return 0;
        wpa_printf(MSG_DEBUG, "WPS:  * Selected Registrar");
        wpabuf_put_be16(msg, ATTR_SELECTED_REGISTRAR);
        wpabuf_put_be16(msg, 1);
        wpabuf_put_u8(msg, 1);
        return 0;
}


static int wps_build_sel_reg_dev_password_id(struct wps_registrar *reg,
                                             struct wpabuf *msg)
{
        u16 id = reg->pbc ? DEV_PW_PUSHBUTTON : DEV_PW_DEFAULT;
        if (!reg->selected_registrar)
                return 0;
        if (reg->sel_reg_dev_password_id_override >= 0)
                id = reg->sel_reg_dev_password_id_override;
        wpa_printf(MSG_DEBUG, "WPS:  * Device Password ID (%d)", id);
        wpabuf_put_be16(msg, ATTR_DEV_PASSWORD_ID);
        wpabuf_put_be16(msg, 2);
        wpabuf_put_be16(msg, id);
        return 0;
}


static int wps_build_sel_reg_config_methods(struct wps_registrar *reg,
                                            struct wpabuf *msg)
{
        u16 methods;
        if (!reg->selected_registrar)
                return 0;
        methods = reg->wps->config_methods & ~WPS_CONFIG_PUSHBUTTON;
        if (reg->pbc)
                methods |= WPS_CONFIG_PUSHBUTTON;
        if (reg->sel_reg_config_methods_override >= 0)
                methods = reg->sel_reg_config_methods_override;
        wpa_printf(MSG_DEBUG, "WPS:  * Selected Registrar Config Methods (%x)",
                   methods);
        wpabuf_put_be16(msg, ATTR_SELECTED_REGISTRAR_CONFIG_METHODS);
        wpabuf_put_be16(msg, 2);
        wpabuf_put_be16(msg, methods);
        return 0;
}


static int wps_build_probe_config_methods(struct wps_registrar *reg,
                                          struct wpabuf *msg)
{
        u16 methods;
        methods = 0;
        wpa_printf(MSG_DEBUG, "WPS:  * Config Methods (%x)", methods);
        wpabuf_put_be16(msg, ATTR_CONFIG_METHODS);
        wpabuf_put_be16(msg, 2);
        wpabuf_put_be16(msg, methods);
        return 0;
}


static int wps_build_config_methods_r(struct wps_registrar *reg,
                                      struct wpabuf *msg)
{
        u16 methods;
        methods = reg->wps->config_methods & ~WPS_CONFIG_PUSHBUTTON;
        if (reg->pbc)
                methods |= WPS_CONFIG_PUSHBUTTON;
        return wps_build_config_methods(msg, methods);
}


static int wps_build_resp_type(struct wps_registrar *reg, struct wpabuf *msg)
{
        u8 resp = reg->wps->ap ? WPS_RESP_AP : WPS_RESP_REGISTRAR;
        wpa_printf(MSG_DEBUG, "WPS:  * Response Type (%d)", resp);
        wpabuf_put_be16(msg, ATTR_RESPONSE_TYPE);
        wpabuf_put_be16(msg, 1);
        wpabuf_put_u8(msg, resp);
        return 0;
}


struct wps_registrar *
wps_registrar_init(struct wps_context *wps,
                   const struct wps_registrar_config *cfg)
{
        struct wps_registrar *reg = os_zalloc(sizeof(*reg));
        if (reg == NULL)
                return NULL;

        reg->wps = wps;
        reg->new_psk_cb = cfg->new_psk_cb;
        reg->set_ie_cb = cfg->set_ie_cb;
        reg->pin_needed_cb = cfg->pin_needed_cb;
        reg->reg_success_cb = cfg->reg_success_cb;
        reg->set_sel_reg_cb = cfg->set_sel_reg_cb;
        reg->cb_ctx = cfg->cb_ctx;
        reg->skip_cred_build = cfg->skip_cred_build;
        if (cfg->extra_cred) {
                reg->extra_cred = wpabuf_alloc_copy(cfg->extra_cred,
                                                    cfg->extra_cred_len);
                if (reg->extra_cred == NULL) {
                        os_free(reg);
                        return NULL;
                }
        }
        reg->disable_auto_conf = cfg->disable_auto_conf;
        reg->sel_reg_dev_password_id_override = -1;
        reg->sel_reg_config_methods_override = -1;
        reg->static_wep_only = cfg->static_wep_only;

        if (wps_set_ie(reg)) {
                wps_registrar_deinit(reg);
                return NULL;
        }

        return reg;
}


void wps_registrar_deinit(struct wps_registrar *reg)
{
        if (reg == NULL)
                return;
        eloop_cancel_timeout(wps_registrar_pbc_timeout, reg, NULL);
        eloop_cancel_timeout(wps_registrar_set_selected_timeout, reg, NULL);
        wps_free_pins(reg->pins);
        wps_free_pbc_sessions(reg->pbc_sessions);
        wpabuf_free(reg->extra_cred);
        wps_free_devices(reg->devices);
        os_free(reg);
}


int wps_registrar_add_pin(struct wps_registrar *reg, const u8 *uuid,
                          const u8 *pin, size_t pin_len, int timeout)
{
        struct wps_uuid_pin *p;

        p = os_zalloc(sizeof(*p));
        if (p == NULL)
                return -1;
        if (uuid == NULL)
                p->wildcard_uuid = 1;
        else
                os_memcpy(p->uuid, uuid, WPS_UUID_LEN);
        p->pin = os_malloc(pin_len);
        if (p->pin == NULL) {
                os_free(p);
                return -1;
        }
        os_memcpy(p->pin, pin, pin_len);
        p->pin_len = pin_len;

        if (timeout) {
                p->flags |= PIN_EXPIRES;
                os_get_time(&p->expiration);
                p->expiration.sec += timeout;
        }

        p->next = reg->pins;
        reg->pins = p;

        wpa_printf(MSG_DEBUG, "WPS: A new PIN configured (timeout=%d)",
                   timeout);
        wpa_hexdump(MSG_DEBUG, "WPS: UUID", uuid, WPS_UUID_LEN);
        wpa_hexdump_ascii_key(MSG_DEBUG, "WPS: PIN", pin, pin_len);
        reg->selected_registrar = 1;
        reg->pbc = 0;
        wps_set_ie(reg);
        wps_cb_set_sel_reg(reg);
        eloop_cancel_timeout(wps_registrar_set_selected_timeout, reg, NULL);
        eloop_register_timeout(WPS_PBC_WALK_TIME, 0,
                               wps_registrar_set_selected_timeout,
                               reg, NULL);

        return 0;
}


static void wps_registrar_expire_pins(struct wps_registrar *reg)
{
        struct wps_uuid_pin *pin, *prev, *del;
        struct os_time now;

        os_get_time(&now);
        prev = NULL;
        pin = reg->pins;
        while (pin) {
                if ((pin->flags & PIN_EXPIRES) &&
                    os_time_before(&pin->expiration, &now)) {
                        if (prev == NULL)
                                reg->pins = pin->next;
                        else
                                prev->next = pin->next;
                        del = pin;
                        pin = pin->next;
                        wpa_hexdump(MSG_DEBUG, "WPS: Expired PIN for UUID",
                                    del->uuid, WPS_UUID_LEN);
                        wps_free_pin(del);
                        continue;
                }
                prev = pin;
                pin = pin->next;
        }
}


int wps_registrar_invalidate_pin(struct wps_registrar *reg, const u8 *uuid)
{
        struct wps_uuid_pin *pin, *prev;

        prev = NULL;
        pin = reg->pins;
        while (pin) {
                if (os_memcmp(pin->uuid, uuid, WPS_UUID_LEN) == 0) {
                        if (prev == NULL)
                                reg->pins = pin->next;
                        else
                                prev->next = pin->next;
                        wpa_hexdump(MSG_DEBUG, "WPS: Invalidated PIN for UUID",
                                    pin->uuid, WPS_UUID_LEN);
                        wps_free_pin(pin);
                        return 0;
                }
                prev = pin;
                pin = pin->next;
        }

        return -1;
}


static const u8 * wps_registrar_get_pin(struct wps_registrar *reg,
                                        const u8 *uuid, size_t *pin_len)
{
        struct wps_uuid_pin *pin;

        wps_registrar_expire_pins(reg);

        pin = reg->pins;
        while (pin) {
                if (!pin->wildcard_uuid &&
                    os_memcmp(pin->uuid, uuid, WPS_UUID_LEN) == 0)
                        break;
                pin = pin->next;
        }

        if (!pin) {
                /* Check for wildcard UUIDs since none of the UUID-specific
                 * PINs matched */
                pin = reg->pins;
                while (pin) {
                        if (pin->wildcard_uuid == 1) {
                                wpa_printf(MSG_DEBUG, "WPS: Found a wildcard "
                                           "PIN. Assigned it for this UUID-E");
                                pin->wildcard_uuid = 2;
                                os_memcpy(pin->uuid, uuid, WPS_UUID_LEN);
                                break;
                        }
                        pin = pin->next;
                }
        }

        if (!pin)
                return NULL;

        /*
         * Lock the PIN to avoid attacks based on concurrent re-use of the PIN
         * that could otherwise avoid PIN invalidations.
         */
        if (pin->flags & PIN_LOCKED) {
                wpa_printf(MSG_DEBUG, "WPS: Selected PIN locked - do not "
                           "allow concurrent re-use");
                return NULL;
        }
        *pin_len = pin->pin_len;
        pin->flags |= PIN_LOCKED;
        return pin->pin;
}


int wps_registrar_unlock_pin(struct wps_registrar *reg, const u8 *uuid)
{
        struct wps_uuid_pin *pin;

        pin = reg->pins;
        while (pin) {
                if (os_memcmp(pin->uuid, uuid, WPS_UUID_LEN) == 0) {
                        if (pin->wildcard_uuid == 2) {
                                wpa_printf(MSG_DEBUG, "WPS: Invalidating used "
                                           "wildcard PIN");
                                return wps_registrar_invalidate_pin(reg, uuid);
                        }
                        pin->flags &= ~PIN_LOCKED;
                        return 0;
                }
                pin = pin->next;
        }

        return -1;
}


static void wps_registrar_stop_pbc(struct wps_registrar *reg)
{
        reg->selected_registrar = 0;
        reg->pbc = 0;
        wps_set_ie(reg);
        wps_cb_set_sel_reg(reg);
}


static void wps_registrar_pbc_timeout(void *eloop_ctx, void *timeout_ctx)
{
        struct wps_registrar *reg = eloop_ctx;

        wpa_printf(MSG_DEBUG, "WPS: PBC timed out - disable PBC mode");
        wps_pbc_timeout_event(reg->wps);
        wps_registrar_stop_pbc(reg);
}


int wps_registrar_button_pushed(struct wps_registrar *reg)
{
        if (wps_registrar_pbc_overlap(reg, NULL, NULL)) {
                wpa_printf(MSG_DEBUG, "WPS: PBC overlap - do not start PBC "
                           "mode");
                wps_pbc_overlap_event(reg->wps);
                return -1;
        }
        wpa_printf(MSG_DEBUG, "WPS: Button pushed - PBC mode started");
        reg->force_pbc_overlap = 0;
        reg->selected_registrar = 1;
        reg->pbc = 1;
        wps_set_ie(reg);
        wps_cb_set_sel_reg(reg);

        eloop_cancel_timeout(wps_registrar_pbc_timeout, reg, NULL);
        eloop_register_timeout(WPS_PBC_WALK_TIME, 0, wps_registrar_pbc_timeout,
                               reg, NULL);
        return 0;
}


static void wps_registrar_pbc_completed(struct wps_registrar *reg)
{
        wpa_printf(MSG_DEBUG, "WPS: PBC completed - stopping PBC mode");
        eloop_cancel_timeout(wps_registrar_pbc_timeout, reg, NULL);
        wps_registrar_stop_pbc(reg);
}

static void wps_registrar_pin_completed(struct wps_registrar *reg)
{
        wpa_printf(MSG_DEBUG, "WPS: PIN completed using internal Registrar");
        eloop_cancel_timeout(wps_registrar_set_selected_timeout, reg, NULL);
        reg->selected_registrar = 0;
        wps_set_ie(reg);
        wps_cb_set_sel_reg(reg);
}


void wps_registrar_probe_req_rx(struct wps_registrar *reg, const u8 *addr,
                                const struct wpabuf *wps_data)
{
        struct wps_parse_attr attr;
        u16 methods;

        wpa_hexdump_buf(MSG_MSGDUMP,
                        "WPS: Probe Request with WPS data received",
                        wps_data);

        if (wps_parse_msg(wps_data, &attr) < 0)
                return;
        if (!wps_version_supported(attr.version)) {
                wpa_printf(MSG_DEBUG, "WPS: Unsupported ProbeReq WPS IE "
                           "version 0x%x", attr.version ? *attr.version : 0);
                return;
        }

        if (attr.config_methods == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Config Methods attribute in "
                           "Probe Request");
                return;
        }

        methods = WPA_GET_BE16(attr.config_methods);
        if (!(methods & WPS_CONFIG_PUSHBUTTON))
                return; /* Not PBC */

        wpa_printf(MSG_DEBUG, "WPS: Probe Request for PBC received from "
                   MACSTR, MAC2STR(addr));

        wps_registrar_add_pbc_session(reg, addr, attr.uuid_e);
        if (wps_registrar_pbc_overlap(reg, addr, attr.uuid_e)) {
                wpa_printf(MSG_DEBUG, "WPS: PBC session overlap detected");
                reg->force_pbc_overlap = 1;
                wps_pbc_overlap_event(reg->wps);
        }
}


static int wps_cb_new_psk(struct wps_registrar *reg, const u8 *mac_addr,
                          const u8 *psk, size_t psk_len)
{
        if (reg->new_psk_cb == NULL)
                return 0;

        return reg->new_psk_cb(reg->cb_ctx, mac_addr, psk, psk_len);
}


static void wps_cb_pin_needed(struct wps_registrar *reg, const u8 *uuid_e,
                              const struct wps_device_data *dev)
{
        if (reg->pin_needed_cb == NULL)
                return;

        reg->pin_needed_cb(reg->cb_ctx, uuid_e, dev);
}


static void wps_cb_reg_success(struct wps_registrar *reg, const u8 *mac_addr,
                               const u8 *uuid_e)
{
        if (reg->reg_success_cb == NULL)
                return;

        reg->reg_success_cb(reg->cb_ctx, mac_addr, uuid_e);
}


static int wps_cb_set_ie(struct wps_registrar *reg,
                         const struct wpabuf *beacon_ie,
                         const struct wpabuf *probe_resp_ie)
{
        if (reg->set_ie_cb == NULL)
                return 0;

        return reg->set_ie_cb(reg->cb_ctx, wpabuf_head(beacon_ie),
                              wpabuf_len(beacon_ie),
                              wpabuf_head(probe_resp_ie),
                              wpabuf_len(probe_resp_ie));
}


static void wps_cb_set_sel_reg(struct wps_registrar *reg)
{
        u16 methods = 0;
        if (reg->set_sel_reg_cb == NULL)
                return;

        if (reg->selected_registrar) {
                methods = reg->wps->config_methods & ~WPS_CONFIG_PUSHBUTTON;
                if (reg->pbc)
                        methods |= WPS_CONFIG_PUSHBUTTON;
        }

        reg->set_sel_reg_cb(reg->cb_ctx, reg->selected_registrar,
                            reg->pbc ? DEV_PW_PUSHBUTTON : DEV_PW_DEFAULT,
                            methods);
}


/* Encapsulate WPS IE data with one (or more, if needed) IE headers */
static struct wpabuf * wps_ie_encapsulate(struct wpabuf *data)
{
        struct wpabuf *ie;
        const u8 *pos, *end;

        ie = wpabuf_alloc(wpabuf_len(data) + 100);
        if (ie == NULL) {
                wpabuf_free(data);
                return NULL;
        }

        pos = wpabuf_head(data);
        end = pos + wpabuf_len(data);

        while (end > pos) {
                size_t frag_len = end - pos;
                if (frag_len > 251)
                        frag_len = 251;
                wpabuf_put_u8(ie, WLAN_EID_VENDOR_SPECIFIC);
                wpabuf_put_u8(ie, 4 + frag_len);
                wpabuf_put_be32(ie, WPS_DEV_OUI_WFA);
                wpabuf_put_data(ie, pos, frag_len);
                pos += frag_len;
        }

        wpabuf_free(data);

        return ie;
}


static int wps_set_ie(struct wps_registrar *reg)
{
        struct wpabuf *beacon;
        struct wpabuf *probe;
        int ret;

        wpa_printf(MSG_DEBUG, "WPS: Build Beacon and Probe Response IEs");

        beacon = wpabuf_alloc(300);
        if (beacon == NULL)
                return -1;
        probe = wpabuf_alloc(400);
        if (probe == NULL) {
                wpabuf_free(beacon);
                return -1;
        }

        if (wps_build_version(beacon) ||
            wps_build_wps_state(reg->wps, beacon) ||
            wps_build_ap_setup_locked(reg->wps, beacon) ||
            wps_build_selected_registrar(reg, beacon) ||
            wps_build_sel_reg_dev_password_id(reg, beacon) ||
            wps_build_sel_reg_config_methods(reg, beacon) ||
            wps_build_version(probe) ||
            wps_build_wps_state(reg->wps, probe) ||
            wps_build_ap_setup_locked(reg->wps, probe) ||
            wps_build_selected_registrar(reg, probe) ||
            wps_build_sel_reg_dev_password_id(reg, probe) ||
            wps_build_sel_reg_config_methods(reg, probe) ||
            wps_build_resp_type(reg, probe) ||
            wps_build_uuid_e(probe, reg->wps->uuid) ||
            wps_build_device_attrs(&reg->wps->dev, probe) ||
            wps_build_probe_config_methods(reg, probe) ||
            wps_build_rf_bands(&reg->wps->dev, probe)) {
                wpabuf_free(beacon);
                wpabuf_free(probe);
                return -1;
        }

        beacon = wps_ie_encapsulate(beacon);
        probe = wps_ie_encapsulate(probe);

        if (!beacon || !probe) {
                wpabuf_free(beacon);
                wpabuf_free(probe);
                return -1;
        }

        if (reg->static_wep_only) {
                /*
                 * Windows XP and Vista clients can get confused about
                 * EAP-Identity/Request when they probe the network with
                 * EAPOL-Start. In such a case, they may assume the network is
                 * using IEEE 802.1X and prompt user for a certificate while
                 * the correct (non-WPS) behavior would be to ask for the
                 * static WEP key. As a workaround, use Microsoft Provisioning
                 * IE to advertise that legacy 802.1X is not supported.
                 */
                const u8 ms_wps[7] = {
                        WLAN_EID_VENDOR_SPECIFIC, 5,
                        /* Microsoft Provisioning IE (00:50:f2:5) */
                        0x00, 0x50, 0xf2, 5,
                        0x00 /* no legacy 802.1X or MS WPS */
                };
                wpa_printf(MSG_DEBUG, "WPS: Add Microsoft Provisioning IE "
                           "into Beacon/Probe Response frames");
                wpabuf_put_data(beacon, ms_wps, sizeof(ms_wps));
                wpabuf_put_data(probe, ms_wps, sizeof(ms_wps));
        }

        ret = wps_cb_set_ie(reg, beacon, probe);
        wpabuf_free(beacon);
        wpabuf_free(probe);

        return ret;
}


static int wps_get_dev_password(struct wps_data *wps)
{
        const u8 *pin;
        size_t pin_len = 0;

        os_free(wps->dev_password);
        wps->dev_password = NULL;

        if (wps->pbc) {
                wpa_printf(MSG_DEBUG, "WPS: Use default PIN for PBC");
                pin = (const u8 *) "00000000";
                pin_len = 8;
        } else {
                pin = wps_registrar_get_pin(wps->wps->registrar, wps->uuid_e,
                                            &pin_len);
        }
        if (pin == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Device Password available for "
                           "the Enrollee");
                wps_cb_pin_needed(wps->wps->registrar, wps->uuid_e,
                                  &wps->peer_dev);
                return -1;
        }

        wps->dev_password = os_malloc(pin_len);
        if (wps->dev_password == NULL)
                return -1;
        os_memcpy(wps->dev_password, pin, pin_len);
        wps->dev_password_len = pin_len;

        return 0;
}


static int wps_build_uuid_r(struct wps_data *wps, struct wpabuf *msg)
{
        wpa_printf(MSG_DEBUG, "WPS:  * UUID-R");
        wpabuf_put_be16(msg, ATTR_UUID_R);
        wpabuf_put_be16(msg, WPS_UUID_LEN);
        wpabuf_put_data(msg, wps->uuid_r, WPS_UUID_LEN);
        return 0;
}


static int wps_build_r_hash(struct wps_data *wps, struct wpabuf *msg)
{
        u8 *hash;
        const u8 *addr[4];
        size_t len[4];

        if (os_get_random(wps->snonce, 2 * WPS_SECRET_NONCE_LEN) < 0)
                return -1;
        wpa_hexdump(MSG_DEBUG, "WPS: R-S1", wps->snonce, WPS_SECRET_NONCE_LEN);
        wpa_hexdump(MSG_DEBUG, "WPS: R-S2",
                    wps->snonce + WPS_SECRET_NONCE_LEN, WPS_SECRET_NONCE_LEN);

        if (wps->dh_pubkey_e == NULL || wps->dh_pubkey_r == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: DH public keys not available for "
                           "R-Hash derivation");
                return -1;
        }

        wpa_printf(MSG_DEBUG, "WPS:  * R-Hash1");
        wpabuf_put_be16(msg, ATTR_R_HASH1);
        wpabuf_put_be16(msg, SHA256_MAC_LEN);
        hash = wpabuf_put(msg, SHA256_MAC_LEN);
        /* R-Hash1 = HMAC_AuthKey(R-S1 || PSK1 || PK_E || PK_R) */
        addr[0] = wps->snonce;
        len[0] = WPS_SECRET_NONCE_LEN;
        addr[1] = wps->psk1;
        len[1] = WPS_PSK_LEN;
        addr[2] = wpabuf_head(wps->dh_pubkey_e);
        len[2] = wpabuf_len(wps->dh_pubkey_e);
        addr[3] = wpabuf_head(wps->dh_pubkey_r);
        len[3] = wpabuf_len(wps->dh_pubkey_r);
        hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 4, addr, len, hash);
        wpa_hexdump(MSG_DEBUG, "WPS: R-Hash1", hash, SHA256_MAC_LEN);

        wpa_printf(MSG_DEBUG, "WPS:  * R-Hash2");
        wpabuf_put_be16(msg, ATTR_R_HASH2);
        wpabuf_put_be16(msg, SHA256_MAC_LEN);
        hash = wpabuf_put(msg, SHA256_MAC_LEN);
        /* R-Hash2 = HMAC_AuthKey(R-S2 || PSK2 || PK_E || PK_R) */
        addr[0] = wps->snonce + WPS_SECRET_NONCE_LEN;
        addr[1] = wps->psk2;
        hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 4, addr, len, hash);
        wpa_hexdump(MSG_DEBUG, "WPS: R-Hash2", hash, SHA256_MAC_LEN);

        return 0;
}


static int wps_build_r_snonce1(struct wps_data *wps, struct wpabuf *msg)
{
        wpa_printf(MSG_DEBUG, "WPS:  * R-SNonce1");
        wpabuf_put_be16(msg, ATTR_R_SNONCE1);
        wpabuf_put_be16(msg, WPS_SECRET_NONCE_LEN);
        wpabuf_put_data(msg, wps->snonce, WPS_SECRET_NONCE_LEN);
        return 0;
}


static int wps_build_r_snonce2(struct wps_data *wps, struct wpabuf *msg)
{
        wpa_printf(MSG_DEBUG, "WPS:  * R-SNonce2");
        wpabuf_put_be16(msg, ATTR_R_SNONCE2);
        wpabuf_put_be16(msg, WPS_SECRET_NONCE_LEN);
        wpabuf_put_data(msg, wps->snonce + WPS_SECRET_NONCE_LEN,
                        WPS_SECRET_NONCE_LEN);
        return 0;
}


static int wps_build_cred_network_idx(struct wpabuf *msg,
                                      const struct wps_credential *cred)
{
        wpa_printf(MSG_DEBUG, "WPS:  * Network Index");
        wpabuf_put_be16(msg, ATTR_NETWORK_INDEX);
        wpabuf_put_be16(msg, 1);
        wpabuf_put_u8(msg, 1);
        return 0;
}


static int wps_build_cred_ssid(struct wpabuf *msg,
                               const struct wps_credential *cred)
{
        wpa_printf(MSG_DEBUG, "WPS:  * SSID");
        wpabuf_put_be16(msg, ATTR_SSID);
        wpabuf_put_be16(msg, cred->ssid_len);
        wpabuf_put_data(msg, cred->ssid, cred->ssid_len);
        return 0;
}


static int wps_build_cred_auth_type(struct wpabuf *msg,
                                    const struct wps_credential *cred)
{
        wpa_printf(MSG_DEBUG, "WPS:  * Authentication Type (0x%x)",
                   cred->auth_type);
        wpabuf_put_be16(msg, ATTR_AUTH_TYPE);
        wpabuf_put_be16(msg, 2);
        wpabuf_put_be16(msg, cred->auth_type);
        return 0;
}


static int wps_build_cred_encr_type(struct wpabuf *msg,
                                    const struct wps_credential *cred)
{
        wpa_printf(MSG_DEBUG, "WPS:  * Encryption Type (0x%x)",
                   cred->encr_type);
        wpabuf_put_be16(msg, ATTR_ENCR_TYPE);
        wpabuf_put_be16(msg, 2);
        wpabuf_put_be16(msg, cred->encr_type);
        return 0;
}


static int wps_build_cred_network_key(struct wpabuf *msg,
                                      const const struct wps_credential *cred)
{
        wpa_printf(MSG_DEBUG, "WPS:  * Network Key");
        wpabuf_put_be16(msg, ATTR_NETWORK_KEY);
        wpabuf_put_be16(msg, cred->key_len);
        wpabuf_put_data(msg, cred->key, cred->key_len);
        return 0;
}


static int wps_build_cred_mac_addr(struct wpabuf *msg,
                                   const struct wps_credential *cred)
{
        wpa_printf(MSG_DEBUG, "WPS:  * MAC Address (" MACSTR ")",
                   MAC2STR(cred->mac_addr));
        wpabuf_put_be16(msg, ATTR_MAC_ADDR);
        wpabuf_put_be16(msg, ETH_ALEN);
        wpabuf_put_data(msg, cred->mac_addr, ETH_ALEN);
        return 0;
}


static int wps_build_credential(struct wpabuf *msg,
                                const struct wps_credential *cred)
{
        if (wps_build_cred_network_idx(msg, cred) ||
            wps_build_cred_ssid(msg, cred) ||
            wps_build_cred_auth_type(msg, cred) ||
            wps_build_cred_encr_type(msg, cred) ||
            wps_build_cred_network_key(msg, cred) ||
            wps_build_cred_mac_addr(msg, cred))
                return -1;
        return 0;
}


int wps_build_cred(struct wps_data *wps, struct wpabuf *msg)
{
        struct wpabuf *cred;

        if (wps->wps->registrar->skip_cred_build)
                goto skip_cred_build;

        wpa_printf(MSG_DEBUG, "WPS:  * Credential");
        if (wps->use_cred) {
                os_memcpy(&wps->cred, wps->use_cred, sizeof(wps->cred));
                goto use_provided;
        }
        os_memset(&wps->cred, 0, sizeof(wps->cred));

        os_memcpy(wps->cred.ssid, wps->wps->ssid, wps->wps->ssid_len);
        wps->cred.ssid_len = wps->wps->ssid_len;

        /* Select the best authentication and encryption type */
        if (wps->auth_type & WPS_AUTH_WPA2PSK)
                wps->auth_type = WPS_AUTH_WPA2PSK;
        else if (wps->auth_type & WPS_AUTH_WPAPSK)
                wps->auth_type = WPS_AUTH_WPAPSK;
        else if (wps->auth_type & WPS_AUTH_OPEN)
                wps->auth_type = WPS_AUTH_OPEN;
        else if (wps->auth_type & WPS_AUTH_SHARED)
                wps->auth_type = WPS_AUTH_SHARED;
        else {
                wpa_printf(MSG_DEBUG, "WPS: Unsupported auth_type 0x%x",
                           wps->auth_type);
                return -1;
        }
        wps->cred.auth_type = wps->auth_type;

        if (wps->auth_type == WPS_AUTH_WPA2PSK ||
            wps->auth_type == WPS_AUTH_WPAPSK) {
                if (wps->encr_type & WPS_ENCR_AES)
                        wps->encr_type = WPS_ENCR_AES;
                else if (wps->encr_type & WPS_ENCR_TKIP)
                        wps->encr_type = WPS_ENCR_TKIP;
                else {
                        wpa_printf(MSG_DEBUG, "WPS: No suitable encryption "
                                   "type for WPA/WPA2");
                        return -1;
                }
        } else {
                if (wps->encr_type & WPS_ENCR_WEP)
                        wps->encr_type = WPS_ENCR_WEP;
                else if (wps->encr_type & WPS_ENCR_NONE)
                        wps->encr_type = WPS_ENCR_NONE;
                else {
                        wpa_printf(MSG_DEBUG, "WPS: No suitable encryption "
                                   "type for non-WPA/WPA2 mode");
                        return -1;
                }
        }
        wps->cred.encr_type = wps->encr_type;
        /*
         * Set MAC address in the Credential to be the Enrollee's MAC address
         */
        os_memcpy(wps->cred.mac_addr, wps->mac_addr_e, ETH_ALEN);

        if (wps->wps->wps_state == WPS_STATE_NOT_CONFIGURED && wps->wps->ap &&
            !wps->wps->registrar->disable_auto_conf) {
                u8 r[16];
                /* Generate a random passphrase */
                if (os_get_random(r, sizeof(r)) < 0)
                        return -1;
                os_free(wps->new_psk);
                wps->new_psk = base64_encode(r, sizeof(r), &wps->new_psk_len);
                if (wps->new_psk == NULL)
                        return -1;
                wps->new_psk_len--; /* remove newline */
                while (wps->new_psk_len &&
                       wps->new_psk[wps->new_psk_len - 1] == '=')
                        wps->new_psk_len--;
                wpa_hexdump_ascii_key(MSG_DEBUG, "WPS: Generated passphrase",
                                      wps->new_psk, wps->new_psk_len);
                os_memcpy(wps->cred.key, wps->new_psk, wps->new_psk_len);
                wps->cred.key_len = wps->new_psk_len;
        } else if (wps->wps->network_key) {
                os_memcpy(wps->cred.key, wps->wps->network_key,
                          wps->wps->network_key_len);
                wps->cred.key_len = wps->wps->network_key_len;
        } else if (wps->auth_type & (WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK)) {
                char hex[65];
                /* Generate a random per-device PSK */
                os_free(wps->new_psk);
                wps->new_psk_len = 32;
                wps->new_psk = os_malloc(wps->new_psk_len);
                if (wps->new_psk == NULL)
                        return -1;
                if (os_get_random(wps->new_psk, wps->new_psk_len) < 0) {
                        os_free(wps->new_psk);
                        wps->new_psk = NULL;
                        return -1;
                }
                wpa_hexdump_key(MSG_DEBUG, "WPS: Generated per-device PSK",
                                wps->new_psk, wps->new_psk_len);
                wpa_snprintf_hex(hex, sizeof(hex), wps->new_psk,
                                 wps->new_psk_len);
                os_memcpy(wps->cred.key, hex, wps->new_psk_len * 2);
                wps->cred.key_len = wps->new_psk_len * 2;
        }

use_provided:
        cred = wpabuf_alloc(200);
        if (cred == NULL)
                return -1;

        if (wps_build_credential(cred, &wps->cred)) {
                wpabuf_free(cred);
                return -1;
        }

        wpabuf_put_be16(msg, ATTR_CRED);
        wpabuf_put_be16(msg, wpabuf_len(cred));
        wpabuf_put_buf(msg, cred);
        wpabuf_free(cred);

skip_cred_build:
        if (wps->wps->registrar->extra_cred) {
                wpa_printf(MSG_DEBUG, "WPS:  * Credential (pre-configured)");
                wpabuf_put_buf(msg, wps->wps->registrar->extra_cred);
        }

        return 0;
}


static int wps_build_ap_settings(struct wps_data *wps, struct wpabuf *msg)
{
        wpa_printf(MSG_DEBUG, "WPS:  * AP Settings");

        if (wps_build_credential(msg, &wps->cred))
                return -1;

        return 0;
}


static struct wpabuf * wps_build_m2(struct wps_data *wps)
{
        struct wpabuf *msg;

        if (os_get_random(wps->nonce_r, WPS_NONCE_LEN) < 0)
                return NULL;
        wpa_hexdump(MSG_DEBUG, "WPS: Registrar Nonce",
                    wps->nonce_r, WPS_NONCE_LEN);
        wpa_hexdump(MSG_DEBUG, "WPS: UUID-R", wps->uuid_r, WPS_UUID_LEN);

        wpa_printf(MSG_DEBUG, "WPS: Building Message M2");
        msg = wpabuf_alloc(1000);
        if (msg == NULL)
                return NULL;

        if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M2) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_registrar_nonce(wps, msg) ||
            wps_build_uuid_r(wps, msg) ||
            wps_build_public_key(wps, msg) ||
            wps_derive_keys(wps) ||
            wps_build_auth_type_flags(wps, msg) ||
            wps_build_encr_type_flags(wps, msg) ||
            wps_build_conn_type_flags(wps, msg) ||
            wps_build_config_methods_r(wps->wps->registrar, msg) ||
            wps_build_device_attrs(&wps->wps->dev, msg) ||
            wps_build_rf_bands(&wps->wps->dev, msg) ||
            wps_build_assoc_state(wps, msg) ||
            wps_build_config_error(msg, WPS_CFG_NO_ERROR) ||
            wps_build_dev_password_id(msg, wps->dev_pw_id) ||
            wps_build_os_version(&wps->wps->dev, msg) ||
            wps_build_authenticator(wps, msg)) {
                wpabuf_free(msg);
                return NULL;
        }

        wps->state = RECV_M3;
        return msg;
}


static struct wpabuf * wps_build_m2d(struct wps_data *wps)
{
        struct wpabuf *msg;
        u16 err = wps->config_error;

        wpa_printf(MSG_DEBUG, "WPS: Building Message M2D");
        msg = wpabuf_alloc(1000);
        if (msg == NULL)
                return NULL;

        if (wps->wps->ap && wps->wps->ap_setup_locked &&
            err == WPS_CFG_NO_ERROR)
                err = WPS_CFG_SETUP_LOCKED;

        if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M2D) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_registrar_nonce(wps, msg) ||
            wps_build_uuid_r(wps, msg) ||
            wps_build_auth_type_flags(wps, msg) ||
            wps_build_encr_type_flags(wps, msg) ||
            wps_build_conn_type_flags(wps, msg) ||
            wps_build_config_methods_r(wps->wps->registrar, msg) ||
            wps_build_device_attrs(&wps->wps->dev, msg) ||
            wps_build_rf_bands(&wps->wps->dev, msg) ||
            wps_build_assoc_state(wps, msg) ||
            wps_build_config_error(msg, err) ||
            wps_build_os_version(&wps->wps->dev, msg)) {
                wpabuf_free(msg);
                return NULL;
        }

        wps->state = RECV_M2D_ACK;
        return msg;
}


static struct wpabuf * wps_build_m4(struct wps_data *wps)
{
        struct wpabuf *msg, *plain;

        wpa_printf(MSG_DEBUG, "WPS: Building Message M4");

        wps_derive_psk(wps, wps->dev_password, wps->dev_password_len);

        plain = wpabuf_alloc(200);
        if (plain == NULL)
                return NULL;

        msg = wpabuf_alloc(1000);
        if (msg == NULL) {
                wpabuf_free(plain);
                return NULL;
        }

        if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M4) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_r_hash(wps, msg) ||
            wps_build_r_snonce1(wps, plain) ||
            wps_build_key_wrap_auth(wps, plain) ||
            wps_build_encr_settings(wps, msg, plain) ||
            wps_build_authenticator(wps, msg)) {
                wpabuf_free(plain);
                wpabuf_free(msg);
                return NULL;
        }
        wpabuf_free(plain);

        wps->state = RECV_M5;
        return msg;
}


static struct wpabuf * wps_build_m6(struct wps_data *wps)
{
        struct wpabuf *msg, *plain;

        wpa_printf(MSG_DEBUG, "WPS: Building Message M6");

        plain = wpabuf_alloc(200);
        if (plain == NULL)
                return NULL;

        msg = wpabuf_alloc(1000);
        if (msg == NULL) {
                wpabuf_free(plain);
                return NULL;
        }

        if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M6) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_r_snonce2(wps, plain) ||
            wps_build_key_wrap_auth(wps, plain) ||
            wps_build_encr_settings(wps, msg, plain) ||
            wps_build_authenticator(wps, msg)) {
                wpabuf_free(plain);
                wpabuf_free(msg);
                return NULL;
        }
        wpabuf_free(plain);

        wps->wps_pin_revealed = 1;
        wps->state = RECV_M7;
        return msg;
}


static struct wpabuf * wps_build_m8(struct wps_data *wps)
{
        struct wpabuf *msg, *plain;

        wpa_printf(MSG_DEBUG, "WPS: Building Message M8");

        plain = wpabuf_alloc(500);
        if (plain == NULL)
                return NULL;

        msg = wpabuf_alloc(1000);
        if (msg == NULL) {
                wpabuf_free(plain);
                return NULL;
        }

        if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_M8) ||
            wps_build_enrollee_nonce(wps, msg) ||
            ((wps->wps->ap || wps->er) && wps_build_cred(wps, plain)) ||
            (!wps->wps->ap && !wps->er && wps_build_ap_settings(wps, plain)) ||
            wps_build_key_wrap_auth(wps, plain) ||
            wps_build_encr_settings(wps, msg, plain) ||
            wps_build_authenticator(wps, msg)) {
                wpabuf_free(plain);
                wpabuf_free(msg);
                return NULL;
        }
        wpabuf_free(plain);

        wps->state = RECV_DONE;
        return msg;
}


static struct wpabuf * wps_build_wsc_ack(struct wps_data *wps)
{
        struct wpabuf *msg;

        wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_ACK");

        msg = wpabuf_alloc(1000);
        if (msg == NULL)
                return NULL;

        if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_WSC_ACK) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_registrar_nonce(wps, msg)) {
                wpabuf_free(msg);
                return NULL;
        }

        return msg;
}


static struct wpabuf * wps_build_wsc_nack(struct wps_data *wps)
{
        struct wpabuf *msg;

        wpa_printf(MSG_DEBUG, "WPS: Building Message WSC_NACK");

        msg = wpabuf_alloc(1000);
        if (msg == NULL)
                return NULL;

        if (wps_build_version(msg) ||
            wps_build_msg_type(msg, WPS_WSC_NACK) ||
            wps_build_enrollee_nonce(wps, msg) ||
            wps_build_registrar_nonce(wps, msg) ||
            wps_build_config_error(msg, wps->config_error)) {
                wpabuf_free(msg);
                return NULL;
        }

        return msg;
}


struct wpabuf * wps_registrar_get_msg(struct wps_data *wps,
                                      enum wsc_op_code *op_code)
{
        struct wpabuf *msg;

#ifdef CONFIG_WPS_UPNP
        if (wps->wps->wps_upnp) {
                struct upnp_pending_message *p, *prev = NULL;
                if (wps->ext_reg > 1)
                        wps_registrar_free_pending_m2(wps->wps);
                p = wps->wps->upnp_msgs;
                /* TODO: check pending message MAC address */
                while (p && p->next) {
                        prev = p;
                        p = p->next;
                }
                if (p) {
                        wpa_printf(MSG_DEBUG, "WPS: Use pending message from "
                                   "UPnP");
                        if (prev)
                                prev->next = NULL;
                        else
                                wps->wps->upnp_msgs = NULL;
                        msg = p->msg;
                        switch (p->type) {
                        case WPS_WSC_ACK:
                                *op_code = WSC_ACK;
                                break;
                        case WPS_WSC_NACK:
                                *op_code = WSC_NACK;
                                break;
                        default:
                                *op_code = WSC_MSG;
                                break;
                        }
                        os_free(p);
                        if (wps->ext_reg == 0)
                                wps->ext_reg = 1;
                        return msg;
                }
        }
        if (wps->ext_reg) {
                wpa_printf(MSG_DEBUG, "WPS: Using external Registrar, but no "
                           "pending message available");
                return NULL;
        }
#endif /* CONFIG_WPS_UPNP */

        switch (wps->state) {
        case SEND_M2:
                if (wps_get_dev_password(wps) < 0)
                        msg = wps_build_m2d(wps);
                else
                        msg = wps_build_m2(wps);
                *op_code = WSC_MSG;
                break;
        case SEND_M2D:
                msg = wps_build_m2d(wps);
                *op_code = WSC_MSG;
                break;
        case SEND_M4:
                msg = wps_build_m4(wps);
                *op_code = WSC_MSG;
                break;
        case SEND_M6:
                msg = wps_build_m6(wps);
                *op_code = WSC_MSG;
                break;
        case SEND_M8:
                msg = wps_build_m8(wps);
                *op_code = WSC_MSG;
                break;
        case RECV_DONE:
                msg = wps_build_wsc_ack(wps);
                *op_code = WSC_ACK;
                break;
        case SEND_WSC_NACK:
                msg = wps_build_wsc_nack(wps);
                *op_code = WSC_NACK;
                break;
        default:
                wpa_printf(MSG_DEBUG, "WPS: Unsupported state %d for building "
                           "a message", wps->state);
                msg = NULL;
                break;
        }

        if (*op_code == WSC_MSG && msg) {
                /* Save a copy of the last message for Authenticator derivation
                 */
                wpabuf_free(wps->last_msg);
                wps->last_msg = wpabuf_dup(msg);
        }

        return msg;
}


static int wps_process_enrollee_nonce(struct wps_data *wps, const u8 *e_nonce)
{
        if (e_nonce == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Enrollee Nonce received");
                return -1;
        }

        os_memcpy(wps->nonce_e, e_nonce, WPS_NONCE_LEN);
        wpa_hexdump(MSG_DEBUG, "WPS: Enrollee Nonce",
                    wps->nonce_e, WPS_NONCE_LEN);

        return 0;
}


static int wps_process_registrar_nonce(struct wps_data *wps, const u8 *r_nonce)
{
        if (r_nonce == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Registrar Nonce received");
                return -1;
        }

        if (os_memcmp(wps->nonce_r, r_nonce, WPS_NONCE_LEN) != 0) {
                wpa_printf(MSG_DEBUG, "WPS: Invalid Registrar Nonce received");
                return -1;
        }

        return 0;
}


static int wps_process_uuid_e(struct wps_data *wps, const u8 *uuid_e)
{
        if (uuid_e == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No UUID-E received");
                return -1;
        }

        os_memcpy(wps->uuid_e, uuid_e, WPS_UUID_LEN);
        wpa_hexdump(MSG_DEBUG, "WPS: UUID-E", wps->uuid_e, WPS_UUID_LEN);

        return 0;
}


static int wps_process_dev_password_id(struct wps_data *wps, const u8 *pw_id)
{
        if (pw_id == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Device Password ID received");
                return -1;
        }

        wps->dev_pw_id = WPA_GET_BE16(pw_id);
        wpa_printf(MSG_DEBUG, "WPS: Device Password ID %d", wps->dev_pw_id);

        return 0;
}


static int wps_process_e_hash1(struct wps_data *wps, const u8 *e_hash1)
{
        if (e_hash1 == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No E-Hash1 received");
                return -1;
        }

        os_memcpy(wps->peer_hash1, e_hash1, WPS_HASH_LEN);
        wpa_hexdump(MSG_DEBUG, "WPS: E-Hash1", wps->peer_hash1, WPS_HASH_LEN);

        return 0;
}


static int wps_process_e_hash2(struct wps_data *wps, const u8 *e_hash2)
{
        if (e_hash2 == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No E-Hash2 received");
                return -1;
        }

        os_memcpy(wps->peer_hash2, e_hash2, WPS_HASH_LEN);
        wpa_hexdump(MSG_DEBUG, "WPS: E-Hash2", wps->peer_hash2, WPS_HASH_LEN);

        return 0;
}


static int wps_process_e_snonce1(struct wps_data *wps, const u8 *e_snonce1)
{
        u8 hash[SHA256_MAC_LEN];
        const u8 *addr[4];
        size_t len[4];

        if (e_snonce1 == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No E-SNonce1 received");
                return -1;
        }

        wpa_hexdump_key(MSG_DEBUG, "WPS: E-SNonce1", e_snonce1,
                        WPS_SECRET_NONCE_LEN);

        /* E-Hash1 = HMAC_AuthKey(E-S1 || PSK1 || PK_E || PK_R) */
        addr[0] = e_snonce1;
        len[0] = WPS_SECRET_NONCE_LEN;
        addr[1] = wps->psk1;
        len[1] = WPS_PSK_LEN;
        addr[2] = wpabuf_head(wps->dh_pubkey_e);
        len[2] = wpabuf_len(wps->dh_pubkey_e);
        addr[3] = wpabuf_head(wps->dh_pubkey_r);
        len[3] = wpabuf_len(wps->dh_pubkey_r);
        hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 4, addr, len, hash);

        if (os_memcmp(wps->peer_hash1, hash, WPS_HASH_LEN) != 0) {
                wpa_printf(MSG_DEBUG, "WPS: E-Hash1 derived from E-S1 does "
                           "not match with the pre-committed value");
                wps->config_error = WPS_CFG_DEV_PASSWORD_AUTH_FAILURE;
                wps_pwd_auth_fail_event(wps->wps, 0, 1);
                return -1;
        }

        wpa_printf(MSG_DEBUG, "WPS: Enrollee proved knowledge of the first "
                   "half of the device password");

        return 0;
}


static int wps_process_e_snonce2(struct wps_data *wps, const u8 *e_snonce2)
{
        u8 hash[SHA256_MAC_LEN];
        const u8 *addr[4];
        size_t len[4];

        if (e_snonce2 == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No E-SNonce2 received");
                return -1;
        }

        wpa_hexdump_key(MSG_DEBUG, "WPS: E-SNonce2", e_snonce2,
                        WPS_SECRET_NONCE_LEN);

        /* E-Hash2 = HMAC_AuthKey(E-S2 || PSK2 || PK_E || PK_R) */
        addr[0] = e_snonce2;
        len[0] = WPS_SECRET_NONCE_LEN;
        addr[1] = wps->psk2;
        len[1] = WPS_PSK_LEN;
        addr[2] = wpabuf_head(wps->dh_pubkey_e);
        len[2] = wpabuf_len(wps->dh_pubkey_e);
        addr[3] = wpabuf_head(wps->dh_pubkey_r);
        len[3] = wpabuf_len(wps->dh_pubkey_r);
        hmac_sha256_vector(wps->authkey, WPS_AUTHKEY_LEN, 4, addr, len, hash);

        if (os_memcmp(wps->peer_hash2, hash, WPS_HASH_LEN) != 0) {
                wpa_printf(MSG_DEBUG, "WPS: E-Hash2 derived from E-S2 does "
                           "not match with the pre-committed value");
                wps_registrar_invalidate_pin(wps->wps->registrar, wps->uuid_e);
                wps->config_error = WPS_CFG_DEV_PASSWORD_AUTH_FAILURE;
                wps_pwd_auth_fail_event(wps->wps, 0, 2);
                return -1;
        }

        wpa_printf(MSG_DEBUG, "WPS: Enrollee proved knowledge of the second "
                   "half of the device password");
        wps->wps_pin_revealed = 0;
        wps_registrar_unlock_pin(wps->wps->registrar, wps->uuid_e);

        return 0;
}


static int wps_process_mac_addr(struct wps_data *wps, const u8 *mac_addr)
{
        if (mac_addr == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No MAC Address received");
                return -1;
        }

        wpa_printf(MSG_DEBUG, "WPS: Enrollee MAC Address " MACSTR,
                   MAC2STR(mac_addr));
        os_memcpy(wps->mac_addr_e, mac_addr, ETH_ALEN);
        os_memcpy(wps->peer_dev.mac_addr, mac_addr, ETH_ALEN);

        return 0;
}


static int wps_process_pubkey(struct wps_data *wps, const u8 *pk,
                              size_t pk_len)
{
        if (pk == NULL || pk_len == 0) {
                wpa_printf(MSG_DEBUG, "WPS: No Public Key received");
                return -1;
        }

#ifdef CONFIG_WPS_OOB
        if (wps->wps->oob_conf.pubkey_hash != NULL) {
                const u8 *addr[1];
                u8 hash[WPS_HASH_LEN];

                addr[0] = pk;
                sha256_vector(1, addr, &pk_len, hash);
                if (os_memcmp(hash,
                              wpabuf_head(wps->wps->oob_conf.pubkey_hash),
                              WPS_OOB_PUBKEY_HASH_LEN) != 0) {
                        wpa_printf(MSG_ERROR, "WPS: Public Key hash error");
                        return -1;
                }
        }
#endif /* CONFIG_WPS_OOB */

        wpabuf_free(wps->dh_pubkey_e);
        wps->dh_pubkey_e = wpabuf_alloc_copy(pk, pk_len);
        if (wps->dh_pubkey_e == NULL)
                return -1;

        return 0;
}


static int wps_process_auth_type_flags(struct wps_data *wps, const u8 *auth)
{
        u16 auth_types;

        if (auth == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Authentication Type flags "
                           "received");
                return -1;
        }

        auth_types = WPA_GET_BE16(auth);

        wpa_printf(MSG_DEBUG, "WPS: Enrollee Authentication Type flags 0x%x",
                   auth_types);
        wps->auth_type = wps->wps->auth_types & auth_types;
        if (wps->auth_type == 0) {
                wpa_printf(MSG_DEBUG, "WPS: No match in supported "
                           "authentication types (own 0x%x Enrollee 0x%x)",
                           wps->wps->auth_types, auth_types);
#ifdef WPS_WORKAROUNDS
                /*
                 * Some deployed implementations seem to advertise incorrect
                 * information in this attribute. For example, Linksys WRT350N
                 * seems to have a byteorder bug that breaks this negotiation.
                 * In order to interoperate with existing implementations,
                 * assume that the Enrollee supports everything we do.
                 */
                wpa_printf(MSG_DEBUG, "WPS: Workaround - assume Enrollee "
                           "does not advertise supported authentication types "
                           "correctly");
                wps->auth_type = wps->wps->auth_types;
#else /* WPS_WORKAROUNDS */
                return -1;
#endif /* WPS_WORKAROUNDS */
        }

        return 0;
}


static int wps_process_encr_type_flags(struct wps_data *wps, const u8 *encr)
{
        u16 encr_types;

        if (encr == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Encryption Type flags "
                           "received");
                return -1;
        }

        encr_types = WPA_GET_BE16(encr);

        wpa_printf(MSG_DEBUG, "WPS: Enrollee Encryption Type flags 0x%x",
                   encr_types);
        wps->encr_type = wps->wps->encr_types & encr_types;
        if (wps->encr_type == 0) {
                wpa_printf(MSG_DEBUG, "WPS: No match in supported "
                           "encryption types (own 0x%x Enrollee 0x%x)",
                           wps->wps->encr_types, encr_types);
#ifdef WPS_WORKAROUNDS
                /*
                 * Some deployed implementations seem to advertise incorrect
                 * information in this attribute. For example, Linksys WRT350N
                 * seems to have a byteorder bug that breaks this negotiation.
                 * In order to interoperate with existing implementations,
                 * assume that the Enrollee supports everything we do.
                 */
                wpa_printf(MSG_DEBUG, "WPS: Workaround - assume Enrollee "
                           "does not advertise supported encryption types "
                           "correctly");
                wps->encr_type = wps->wps->encr_types;
#else /* WPS_WORKAROUNDS */
                return -1;
#endif /* WPS_WORKAROUNDS */
        }

        return 0;
}


static int wps_process_conn_type_flags(struct wps_data *wps, const u8 *conn)
{
        if (conn == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Connection Type flags "
                           "received");
                return -1;
        }

        wpa_printf(MSG_DEBUG, "WPS: Enrollee Connection Type flags 0x%x",
                   *conn);

        return 0;
}


static int wps_process_config_methods(struct wps_data *wps, const u8 *methods)
{
        u16 m;

        if (methods == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Config Methods received");
                return -1;
        }

        m = WPA_GET_BE16(methods);

        wpa_printf(MSG_DEBUG, "WPS: Enrollee Config Methods 0x%x", m);

        return 0;
}


static int wps_process_wps_state(struct wps_data *wps, const u8 *state)
{
        if (state == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Wi-Fi Protected Setup State "
                           "received");
                return -1;
        }

        wpa_printf(MSG_DEBUG, "WPS: Enrollee Wi-Fi Protected Setup State %d",
                   *state);

        return 0;
}


static int wps_process_assoc_state(struct wps_data *wps, const u8 *assoc)
{
        u16 a;

        if (assoc == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Association State received");
                return -1;
        }

        a = WPA_GET_BE16(assoc);
        wpa_printf(MSG_DEBUG, "WPS: Enrollee Association State %d", a);

        return 0;
}


static int wps_process_config_error(struct wps_data *wps, const u8 *err)
{
        u16 e;

        if (err == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Configuration Error received");
                return -1;
        }

        e = WPA_GET_BE16(err);
        wpa_printf(MSG_DEBUG, "WPS: Enrollee Configuration Error %d", e);

        return 0;
}


static enum wps_process_res wps_process_m1(struct wps_data *wps,
                                           struct wps_parse_attr *attr)
{
        wpa_printf(MSG_DEBUG, "WPS: Received M1");

        if (wps->state != RECV_M1) {
                wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                           "receiving M1", wps->state);
                return WPS_FAILURE;
        }

        if (wps_process_uuid_e(wps, attr->uuid_e) ||
            wps_process_mac_addr(wps, attr->mac_addr) ||
            wps_process_enrollee_nonce(wps, attr->enrollee_nonce) ||
            wps_process_pubkey(wps, attr->public_key, attr->public_key_len) ||
            wps_process_auth_type_flags(wps, attr->auth_type_flags) ||
            wps_process_encr_type_flags(wps, attr->encr_type_flags) ||
            wps_process_conn_type_flags(wps, attr->conn_type_flags) ||
            wps_process_config_methods(wps, attr->config_methods) ||
            wps_process_wps_state(wps, attr->wps_state) ||
            wps_process_device_attrs(&wps->peer_dev, attr) ||
            wps_process_rf_bands(&wps->peer_dev, attr->rf_bands) ||
            wps_process_assoc_state(wps, attr->assoc_state) ||
            wps_process_dev_password_id(wps, attr->dev_password_id) ||
            wps_process_config_error(wps, attr->config_error) ||
            wps_process_os_version(&wps->peer_dev, attr->os_version))
                return WPS_FAILURE;

        if (wps->dev_pw_id < 0x10 &&
            wps->dev_pw_id != DEV_PW_DEFAULT &&
            wps->dev_pw_id != DEV_PW_USER_SPECIFIED &&
            wps->dev_pw_id != DEV_PW_MACHINE_SPECIFIED &&
            wps->dev_pw_id != DEV_PW_REGISTRAR_SPECIFIED &&
            (wps->dev_pw_id != DEV_PW_PUSHBUTTON ||
             !wps->wps->registrar->pbc)) {
                wpa_printf(MSG_DEBUG, "WPS: Unsupported Device Password ID %d",
                           wps->dev_pw_id);
                wps->state = SEND_M2D;
                return WPS_CONTINUE;
        }

#ifdef CONFIG_WPS_OOB
        if (wps->dev_pw_id >= 0x10 &&
            wps->dev_pw_id != wps->wps->oob_dev_pw_id) {
                wpa_printf(MSG_DEBUG, "WPS: OOB Device Password ID "
                           "%d mismatch", wps->dev_pw_id);
                wps->state = SEND_M2D;
                return WPS_CONTINUE;
        }
#endif /* CONFIG_WPS_OOB */

        if (wps->dev_pw_id == DEV_PW_PUSHBUTTON) {
                if (wps->wps->registrar->force_pbc_overlap ||
                    wps_registrar_pbc_overlap(wps->wps->registrar,
                                              wps->mac_addr_e, wps->uuid_e)) {
                        wpa_printf(MSG_DEBUG, "WPS: PBC overlap - deny PBC "
                                   "negotiation");
                        wps->state = SEND_M2D;
                        wps->config_error = WPS_CFG_MULTIPLE_PBC_DETECTED;
                        wps_pbc_overlap_event(wps->wps);
                        wps->wps->registrar->force_pbc_overlap = 1;
                        return WPS_CONTINUE;
                }
                wps_registrar_add_pbc_session(wps->wps->registrar,
                                              wps->mac_addr_e, wps->uuid_e);
                wps->pbc = 1;
        }

        wps->state = SEND_M2;
        return WPS_CONTINUE;
}


static enum wps_process_res wps_process_m3(struct wps_data *wps,
                                           const struct wpabuf *msg,
                                           struct wps_parse_attr *attr)
{
        wpa_printf(MSG_DEBUG, "WPS: Received M3");

        if (wps->state != RECV_M3) {
                wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                           "receiving M3", wps->state);
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        if (wps->pbc && wps->wps->registrar->force_pbc_overlap) {
                wpa_printf(MSG_DEBUG, "WPS: Reject negotiation due to PBC "
                           "session overlap");
                wps->state = SEND_WSC_NACK;
                wps->config_error = WPS_CFG_MULTIPLE_PBC_DETECTED;
                return WPS_CONTINUE;
        }

        if (wps_process_registrar_nonce(wps, attr->registrar_nonce) ||
            wps_process_authenticator(wps, attr->authenticator, msg) ||
            wps_process_e_hash1(wps, attr->e_hash1) ||
            wps_process_e_hash2(wps, attr->e_hash2)) {
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        wps->state = SEND_M4;
        return WPS_CONTINUE;
}


static enum wps_process_res wps_process_m5(struct wps_data *wps,
                                           const struct wpabuf *msg,
                                           struct wps_parse_attr *attr)
{
        struct wpabuf *decrypted;
        struct wps_parse_attr eattr;

        wpa_printf(MSG_DEBUG, "WPS: Received M5");

        if (wps->state != RECV_M5) {
                wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                           "receiving M5", wps->state);
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        if (wps->pbc && wps->wps->registrar->force_pbc_overlap) {
                wpa_printf(MSG_DEBUG, "WPS: Reject negotiation due to PBC "
                           "session overlap");
                wps->state = SEND_WSC_NACK;
                wps->config_error = WPS_CFG_MULTIPLE_PBC_DETECTED;
                return WPS_CONTINUE;
        }

        if (wps_process_registrar_nonce(wps, attr->registrar_nonce) ||
            wps_process_authenticator(wps, attr->authenticator, msg)) {
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        decrypted = wps_decrypt_encr_settings(wps, attr->encr_settings,
                                              attr->encr_settings_len);
        if (decrypted == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: Failed to decrypted Encrypted "
                           "Settings attribute");
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        wpa_printf(MSG_DEBUG, "WPS: Processing decrypted Encrypted Settings "
                   "attribute");
        if (wps_parse_msg(decrypted, &eattr) < 0 ||
            wps_process_key_wrap_auth(wps, decrypted, eattr.key_wrap_auth) ||
            wps_process_e_snonce1(wps, eattr.e_snonce1)) {
                wpabuf_free(decrypted);
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }
        wpabuf_free(decrypted);

        wps->state = SEND_M6;
        return WPS_CONTINUE;
}


static void wps_sta_cred_cb(struct wps_data *wps)
{
        /*
         * Update credential to only include a single authentication and
         * encryption type in case the AP configuration includes more than one
         * option.
         */
        if (wps->cred.auth_type & WPS_AUTH_WPA2PSK)
                wps->cred.auth_type = WPS_AUTH_WPA2PSK;
        else if (wps->cred.auth_type & WPS_AUTH_WPAPSK)
                wps->cred.auth_type = WPS_AUTH_WPAPSK;
        if (wps->cred.encr_type & WPS_ENCR_AES)
                wps->cred.encr_type = WPS_ENCR_AES;
        else if (wps->cred.encr_type & WPS_ENCR_TKIP)
                wps->cred.encr_type = WPS_ENCR_TKIP;
        wpa_printf(MSG_DEBUG, "WPS: Update local configuration based on the "
                   "AP configuration");
        if (wps->wps->cred_cb)
                wps->wps->cred_cb(wps->wps->cb_ctx, &wps->cred);
}


static void wps_cred_update(struct wps_credential *dst,
                            struct wps_credential *src)
{
        os_memcpy(dst->ssid, src->ssid, sizeof(dst->ssid));
        dst->ssid_len = src->ssid_len;
        dst->auth_type = src->auth_type;
        dst->encr_type = src->encr_type;
        dst->key_idx = src->key_idx;
        os_memcpy(dst->key, src->key, sizeof(dst->key));
        dst->key_len = src->key_len;
}


static int wps_process_ap_settings_r(struct wps_data *wps,
                                     struct wps_parse_attr *attr)
{
        if (wps->wps->ap || wps->er)
                return 0;

        /* AP Settings Attributes in M7 when Enrollee is an AP */
        if (wps_process_ap_settings(attr, &wps->cred) < 0)
                return -1;

        wpa_printf(MSG_INFO, "WPS: Received old AP configuration from AP");

        if (wps->new_ap_settings) {
                wpa_printf(MSG_INFO, "WPS: Update AP configuration based on "
                           "new settings");
                wps_cred_update(&wps->cred, wps->new_ap_settings);
                return 0;
        } else {
                /*
                 * Use the AP PIN only to receive the current AP settings, not
                 * to reconfigure the AP.
                 */
                if (wps->ap_settings_cb) {
                        wps->ap_settings_cb(wps->ap_settings_cb_ctx,
                                            &wps->cred);
                        return 1;
                }
                wps_sta_cred_cb(wps);
                return 1;
        }
}


static enum wps_process_res wps_process_m7(struct wps_data *wps,
                                           const struct wpabuf *msg,
                                           struct wps_parse_attr *attr)
{
        struct wpabuf *decrypted;
        struct wps_parse_attr eattr;

        wpa_printf(MSG_DEBUG, "WPS: Received M7");

        if (wps->state != RECV_M7) {
                wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                           "receiving M7", wps->state);
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        if (wps->pbc && wps->wps->registrar->force_pbc_overlap) {
                wpa_printf(MSG_DEBUG, "WPS: Reject negotiation due to PBC "
                           "session overlap");
                wps->state = SEND_WSC_NACK;
                wps->config_error = WPS_CFG_MULTIPLE_PBC_DETECTED;
                return WPS_CONTINUE;
        }

        if (wps_process_registrar_nonce(wps, attr->registrar_nonce) ||
            wps_process_authenticator(wps, attr->authenticator, msg)) {
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        decrypted = wps_decrypt_encr_settings(wps, attr->encr_settings,
                                              attr->encr_settings_len);
        if (decrypted == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: Failed to decrypt Encrypted "
                           "Settings attribute");
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        wpa_printf(MSG_DEBUG, "WPS: Processing decrypted Encrypted Settings "
                   "attribute");
        if (wps_parse_msg(decrypted, &eattr) < 0 ||
            wps_process_key_wrap_auth(wps, decrypted, eattr.key_wrap_auth) ||
            wps_process_e_snonce2(wps, eattr.e_snonce2) ||
            wps_process_ap_settings_r(wps, &eattr)) {
                wpabuf_free(decrypted);
                wps->state = SEND_WSC_NACK;
                return WPS_CONTINUE;
        }

        wpabuf_free(decrypted);

        wps->state = SEND_M8;
        return WPS_CONTINUE;
}


static enum wps_process_res wps_process_wsc_msg(struct wps_data *wps,
                                                const struct wpabuf *msg)
{
        struct wps_parse_attr attr;
        enum wps_process_res ret = WPS_CONTINUE;

        wpa_printf(MSG_DEBUG, "WPS: Received WSC_MSG");

        if (wps_parse_msg(msg, &attr) < 0)
                return WPS_FAILURE;

        if (!wps_version_supported(attr.version)) {
                wpa_printf(MSG_DEBUG, "WPS: Unsupported message version 0x%x",
                           attr.version ? *attr.version : 0);
                return WPS_FAILURE;
        }

        if (attr.msg_type == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Message Type attribute");
                return WPS_FAILURE;
        }

        if (*attr.msg_type != WPS_M1 &&
            (attr.registrar_nonce == NULL ||
             os_memcmp(wps->nonce_r, attr.registrar_nonce,
                       WPS_NONCE_LEN != 0))) {
                wpa_printf(MSG_DEBUG, "WPS: Mismatch in registrar nonce");
                return WPS_FAILURE;
        }

        switch (*attr.msg_type) {
        case WPS_M1:
#ifdef CONFIG_WPS_UPNP
                if (wps->wps->wps_upnp && attr.mac_addr) {
                        /* Remove old pending messages when starting new run */
                        wps_free_pending_msgs(wps->wps->upnp_msgs);
                        wps->wps->upnp_msgs = NULL;

                        upnp_wps_device_send_wlan_event(
                                wps->wps->wps_upnp, attr.mac_addr,
                                UPNP_WPS_WLANEVENT_TYPE_EAP, msg);
                }
#endif /* CONFIG_WPS_UPNP */
                ret = wps_process_m1(wps, &attr);
                break;
        case WPS_M3:
                ret = wps_process_m3(wps, msg, &attr);
                if (ret == WPS_FAILURE || wps->state == SEND_WSC_NACK)
                        wps_fail_event(wps->wps, WPS_M3);
                break;
        case WPS_M5:
                ret = wps_process_m5(wps, msg, &attr);
                if (ret == WPS_FAILURE || wps->state == SEND_WSC_NACK)
                        wps_fail_event(wps->wps, WPS_M5);
                break;
        case WPS_M7:
                ret = wps_process_m7(wps, msg, &attr);
                if (ret == WPS_FAILURE || wps->state == SEND_WSC_NACK)
                        wps_fail_event(wps->wps, WPS_M7);
                break;
        default:
                wpa_printf(MSG_DEBUG, "WPS: Unsupported Message Type %d",
                           *attr.msg_type);
                return WPS_FAILURE;
        }

        if (ret == WPS_CONTINUE) {
                /* Save a copy of the last message for Authenticator derivation
                 */
                wpabuf_free(wps->last_msg);
                wps->last_msg = wpabuf_dup(msg);
        }

        return ret;
}


static enum wps_process_res wps_process_wsc_ack(struct wps_data *wps,
                                                const struct wpabuf *msg)
{
        struct wps_parse_attr attr;

        wpa_printf(MSG_DEBUG, "WPS: Received WSC_ACK");

        if (wps_parse_msg(msg, &attr) < 0)
                return WPS_FAILURE;

        if (!wps_version_supported(attr.version)) {
                wpa_printf(MSG_DEBUG, "WPS: Unsupported message version 0x%x",
                           attr.version ? *attr.version : 0);
                return WPS_FAILURE;
        }

        if (attr.msg_type == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Message Type attribute");
                return WPS_FAILURE;
        }

        if (*attr.msg_type != WPS_WSC_ACK) {
                wpa_printf(MSG_DEBUG, "WPS: Invalid Message Type %d",
                           *attr.msg_type);
                return WPS_FAILURE;
        }

#ifdef CONFIG_WPS_UPNP
        if (wps->wps->wps_upnp && wps->ext_reg && wps->state == RECV_M2D_ACK &&
            upnp_wps_subscribers(wps->wps->wps_upnp)) {
                if (wps->wps->upnp_msgs)
                        return WPS_CONTINUE;
                wpa_printf(MSG_DEBUG, "WPS: Wait for response from an "
                           "external Registrar");
                return WPS_PENDING;
        }
#endif /* CONFIG_WPS_UPNP */

        if (attr.registrar_nonce == NULL ||
            os_memcmp(wps->nonce_r, attr.registrar_nonce, WPS_NONCE_LEN != 0))
        {
                wpa_printf(MSG_DEBUG, "WPS: Mismatch in registrar nonce");
                return WPS_FAILURE;
        }

        if (attr.enrollee_nonce == NULL ||
            os_memcmp(wps->nonce_e, attr.enrollee_nonce, WPS_NONCE_LEN != 0)) {
                wpa_printf(MSG_DEBUG, "WPS: Mismatch in enrollee nonce");
                return WPS_FAILURE;
        }

        if (wps->state == RECV_M2D_ACK) {
#ifdef CONFIG_WPS_UPNP
                if (wps->wps->wps_upnp &&
                    upnp_wps_subscribers(wps->wps->wps_upnp)) {
                        if (wps->wps->upnp_msgs)
                                return WPS_CONTINUE;
                        if (wps->ext_reg == 0)
                                wps->ext_reg = 1;
                        wpa_printf(MSG_DEBUG, "WPS: Wait for response from an "
                                   "external Registrar");
                        return WPS_PENDING;
                }
#endif /* CONFIG_WPS_UPNP */

                wpa_printf(MSG_DEBUG, "WPS: No more registrars available - "
                           "terminate negotiation");
        }

        return WPS_FAILURE;
}


static enum wps_process_res wps_process_wsc_nack(struct wps_data *wps,
                                                 const struct wpabuf *msg)
{
        struct wps_parse_attr attr;
        int old_state;

        wpa_printf(MSG_DEBUG, "WPS: Received WSC_NACK");

        old_state = wps->state;
        wps->state = SEND_WSC_NACK;

        if (wps_parse_msg(msg, &attr) < 0)
                return WPS_FAILURE;

        if (!wps_version_supported(attr.version)) {
                wpa_printf(MSG_DEBUG, "WPS: Unsupported message version 0x%x",
                           attr.version ? *attr.version : 0);
                return WPS_FAILURE;
        }

        if (attr.msg_type == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Message Type attribute");
                return WPS_FAILURE;
        }

        if (*attr.msg_type != WPS_WSC_NACK) {
                wpa_printf(MSG_DEBUG, "WPS: Invalid Message Type %d",
                           *attr.msg_type);
                return WPS_FAILURE;
        }

#ifdef CONFIG_WPS_UPNP
        if (wps->wps->wps_upnp && wps->ext_reg) {
                wpa_printf(MSG_DEBUG, "WPS: Negotiation using external "
                           "Registrar terminated by the Enrollee");
                return WPS_FAILURE;
        }
#endif /* CONFIG_WPS_UPNP */

        if (attr.registrar_nonce == NULL ||
            os_memcmp(wps->nonce_r, attr.registrar_nonce, WPS_NONCE_LEN != 0))
        {
                wpa_printf(MSG_DEBUG, "WPS: Mismatch in registrar nonce");
                return WPS_FAILURE;
        }

        if (attr.enrollee_nonce == NULL ||
            os_memcmp(wps->nonce_e, attr.enrollee_nonce, WPS_NONCE_LEN != 0)) {
                wpa_printf(MSG_DEBUG, "WPS: Mismatch in enrollee nonce");
                return WPS_FAILURE;
        }

        if (attr.config_error == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Configuration Error attribute "
                           "in WSC_NACK");
                return WPS_FAILURE;
        }

        wpa_printf(MSG_DEBUG, "WPS: Enrollee terminated negotiation with "
                   "Configuration Error %d", WPA_GET_BE16(attr.config_error));

        switch (old_state) {
        case RECV_M3:
                wps_fail_event(wps->wps, WPS_M2);
                break;
        case RECV_M5:
                wps_fail_event(wps->wps, WPS_M4);
                break;
        case RECV_M7:
                wps_fail_event(wps->wps, WPS_M6);
                break;
        case RECV_DONE:
                wps_fail_event(wps->wps, WPS_M8);
                break;
        default:
                break;
        }

        return WPS_FAILURE;
}


static enum wps_process_res wps_process_wsc_done(struct wps_data *wps,
                                                 const struct wpabuf *msg)
{
        struct wps_parse_attr attr;

        wpa_printf(MSG_DEBUG, "WPS: Received WSC_Done");

        if (wps->state != RECV_DONE &&
            (!wps->wps->wps_upnp || !wps->ext_reg)) {
                wpa_printf(MSG_DEBUG, "WPS: Unexpected state (%d) for "
                           "receiving WSC_Done", wps->state);
                return WPS_FAILURE;
        }

        if (wps_parse_msg(msg, &attr) < 0)
                return WPS_FAILURE;

        if (!wps_version_supported(attr.version)) {
                wpa_printf(MSG_DEBUG, "WPS: Unsupported message version 0x%x",
                           attr.version ? *attr.version : 0);
                return WPS_FAILURE;
        }

        if (attr.msg_type == NULL) {
                wpa_printf(MSG_DEBUG, "WPS: No Message Type attribute");
                return WPS_FAILURE;
        }

        if (*attr.msg_type != WPS_WSC_DONE) {
                wpa_printf(MSG_DEBUG, "WPS: Invalid Message Type %d",
                           *attr.msg_type);
                return WPS_FAILURE;
        }

#ifdef CONFIG_WPS_UPNP
        if (wps->wps->wps_upnp && wps->ext_reg) {
                wpa_printf(MSG_DEBUG, "WPS: Negotiation using external "
                           "Registrar completed successfully");
                wps_device_store(wps->wps->registrar, &wps->peer_dev,
                                 wps->uuid_e);
                return WPS_DONE;
        }
#endif /* CONFIG_WPS_UPNP */

        if (attr.registrar_nonce == NULL ||
            os_memcmp(wps->nonce_r, attr.registrar_nonce, WPS_NONCE_LEN != 0))
        {
                wpa_printf(MSG_DEBUG, "WPS: Mismatch in registrar nonce");
                return WPS_FAILURE;
        }

        if (attr.enrollee_nonce == NULL ||
            os_memcmp(wps->nonce_e, attr.enrollee_nonce, WPS_NONCE_LEN != 0)) {
                wpa_printf(MSG_DEBUG, "WPS: Mismatch in enrollee nonce");
                return WPS_FAILURE;
        }

        wpa_printf(MSG_DEBUG, "WPS: Negotiation completed successfully");
        wps_device_store(wps->wps->registrar, &wps->peer_dev,
                         wps->uuid_e);

        if (wps->wps->wps_state == WPS_STATE_NOT_CONFIGURED && wps->new_psk &&
            wps->wps->ap && !wps->wps->registrar->disable_auto_conf) {
                struct wps_credential cred;

                wpa_printf(MSG_DEBUG, "WPS: Moving to Configured state based "
                           "on first Enrollee connection");

                os_memset(&cred, 0, sizeof(cred));
                os_memcpy(cred.ssid, wps->wps->ssid, wps->wps->ssid_len);
                cred.ssid_len = wps->wps->ssid_len;
                cred.auth_type = WPS_AUTH_WPAPSK | WPS_AUTH_WPA2PSK;
                cred.encr_type = WPS_ENCR_TKIP | WPS_ENCR_AES;
                os_memcpy(cred.key, wps->new_psk, wps->new_psk_len);
                cred.key_len = wps->new_psk_len;

                wps->wps->wps_state = WPS_STATE_CONFIGURED;
                wpa_hexdump_ascii_key(MSG_DEBUG,
                                      "WPS: Generated random passphrase",
                                      wps->new_psk, wps->new_psk_len);
                if (wps->wps->cred_cb)
                        wps->wps->cred_cb(wps->wps->cb_ctx, &cred);

                os_free(wps->new_psk);
                wps->new_psk = NULL;
        }

        if (!wps->wps->ap && !wps->er)
                wps_sta_cred_cb(wps);

        if (wps->new_psk) {
                if (wps_cb_new_psk(wps->wps->registrar, wps->mac_addr_e,
                                   wps->new_psk, wps->new_psk_len)) {
                        wpa_printf(MSG_DEBUG, "WPS: Failed to configure the "
                                   "new PSK");
                }
                os_free(wps->new_psk);
                wps->new_psk = NULL;
        }

        wps_cb_reg_success(wps->wps->registrar, wps->mac_addr_e, wps->uuid_e);

        if (wps->pbc) {
                wps_registrar_remove_pbc_session(wps->wps->registrar,
                                                 wps->mac_addr_e, wps->uuid_e);
                wps_registrar_pbc_completed(wps->wps->registrar);
        } else {
                wps_registrar_pin_completed(wps->wps->registrar);
        }

        wps_success_event(wps->wps);

        return WPS_DONE;
}


enum wps_process_res wps_registrar_process_msg(struct wps_data *wps,
                                               enum wsc_op_code op_code,
                                               const struct wpabuf *msg)
{
        enum wps_process_res ret;

        wpa_printf(MSG_DEBUG, "WPS: Processing received message (len=%lu "
                   "op_code=%d)",
                   (unsigned long) wpabuf_len(msg), op_code);

#ifdef CONFIG_WPS_UPNP
        if (wps->wps->wps_upnp && op_code == WSC_MSG && wps->ext_reg == 1) {
                struct wps_parse_attr attr;
                if (wps_parse_msg(msg, &attr) == 0 && attr.msg_type &&
                    *attr.msg_type == WPS_M3)
                        wps->ext_reg = 2; /* past M2/M2D phase */
        }
        if (wps->ext_reg > 1)
                wps_registrar_free_pending_m2(wps->wps);
        if (wps->wps->wps_upnp && wps->ext_reg &&
            wps->wps->upnp_msgs == NULL &&
            (op_code == WSC_MSG || op_code == WSC_Done || op_code == WSC_NACK))
        {
                struct wps_parse_attr attr;
                int type;
                if (wps_parse_msg(msg, &attr) < 0 || attr.msg_type == NULL)
                        type = -1;
                else
                        type = *attr.msg_type;
                wpa_printf(MSG_DEBUG, "WPS: Sending received message (type %d)"
                           " to external Registrar for processing", type);
                upnp_wps_device_send_wlan_event(wps->wps->wps_upnp,
                                                wps->mac_addr_e,
                                                UPNP_WPS_WLANEVENT_TYPE_EAP,
                                                msg);
                if (op_code == WSC_MSG)
                        return WPS_PENDING;
        } else if (wps->wps->wps_upnp && wps->ext_reg && op_code == WSC_MSG) {
                wpa_printf(MSG_DEBUG, "WPS: Skip internal processing - using "
                           "external Registrar");
                return WPS_CONTINUE;
        }
#endif /* CONFIG_WPS_UPNP */

        switch (op_code) {
        case WSC_MSG:
                return wps_process_wsc_msg(wps, msg);
        case WSC_ACK:
                return wps_process_wsc_ack(wps, msg);
        case WSC_NACK:
                return wps_process_wsc_nack(wps, msg);
        case WSC_Done:
                ret = wps_process_wsc_done(wps, msg);
                if (ret == WPS_FAILURE) {
                        wps->state = SEND_WSC_NACK;
                        wps_fail_event(wps->wps, WPS_WSC_DONE);
                }
                return ret;
        default:
                wpa_printf(MSG_DEBUG, "WPS: Unsupported op_code %d", op_code);
                return WPS_FAILURE;
        }
}


int wps_registrar_update_ie(struct wps_registrar *reg)
{
        return wps_set_ie(reg);
}


static void wps_registrar_set_selected_timeout(void *eloop_ctx,
                                               void *timeout_ctx)
{
        struct wps_registrar *reg = eloop_ctx;

        wpa_printf(MSG_DEBUG, "WPS: SetSelectedRegistrar timed out - "
                   "unselect Registrar");
        reg->selected_registrar = 0;
        reg->pbc = 0;
        reg->sel_reg_dev_password_id_override = -1;
        reg->sel_reg_config_methods_override = -1;
        wps_set_ie(reg);
        wps_cb_set_sel_reg(reg);
}


int wps_registrar_set_selected_registrar(struct wps_registrar *reg,
                                         const struct wpabuf *msg)
{
        struct wps_parse_attr attr;

        wpa_hexdump_buf(MSG_MSGDUMP, "WPS: SetSelectedRegistrar attributes",
                        msg);

        if (wps_parse_msg(msg, &attr) < 0)
                return -1;
        if (!wps_version_supported(attr.version)) {
                wpa_printf(MSG_DEBUG, "WPS: Unsupported SetSelectedRegistrar "
                           "version 0x%x", attr.version ? *attr.version : 0);
                return -1;
        }

        if (attr.selected_registrar == NULL ||
            *attr.selected_registrar == 0) {
                wpa_printf(MSG_DEBUG, "WPS: SetSelectedRegistrar: Disable "
                           "Selected Registrar");
                eloop_cancel_timeout(wps_registrar_set_selected_timeout, reg,
                                     NULL);
                wps_registrar_set_selected_timeout(reg, NULL);
                return 0;
        }

        reg->selected_registrar = 1;
        reg->sel_reg_dev_password_id_override = attr.dev_password_id ?
                WPA_GET_BE16(attr.dev_password_id) : DEV_PW_DEFAULT;
        reg->sel_reg_config_methods_override = attr.sel_reg_config_methods ?
                WPA_GET_BE16(attr.sel_reg_config_methods) : -1;
        wps_set_ie(reg);

        eloop_cancel_timeout(wps_registrar_set_selected_timeout, reg, NULL);
        eloop_register_timeout(WPS_PBC_WALK_TIME, 0,
                               wps_registrar_set_selected_timeout,
                               reg, NULL);
        return 0;
}


int wps_registrar_get_info(struct wps_registrar *reg, const u8 *addr,
                           char *buf, size_t buflen)
{
        struct wps_registrar_device *d;
        int len = 0, ret;
        char uuid[40];

        d = wps_device_get(reg, addr);
        if (d == NULL)
                return 0;
        if (uuid_bin2str(d->uuid, uuid, sizeof(uuid)))
                return 0;

        ret = os_snprintf(buf + len, buflen - len,
                          "wpsUuid=%s\n"
                          "wpsPrimaryDeviceType=%u-%08X-%u\n"
                          "wpsDeviceName=%s\n"
                          "wpsManufacturer=%s\n"
                          "wpsModelName=%s\n"
                          "wpsModelNumber=%s\n"
                          "wpsSerialNumber=%s\n",
                          uuid,
                          d->dev.categ, d->dev.oui, d->dev.sub_categ,
                          d->dev.device_name ? d->dev.device_name : "",
                          d->dev.manufacturer ? d->dev.manufacturer : "",
                          d->dev.model_name ? d->dev.model_name : "",
                          d->dev.model_number ? d->dev.model_number : "",
                          d->dev.serial_number ? d->dev.serial_number : "");
        if (ret < 0 || (size_t) ret >= buflen - len)
                return len;
        len += ret;

        return len;
}