From 7ff78eda39f2359bf061bb8a236a21c744bf6032 Mon Sep 17 00:00:00 2001 From: Cy Schubert Date: Mon, 8 Jun 2020 20:35:03 +0000 Subject: [PATCH] Upstream commit message: [PATCH 1/3] WPS UPnP: Do not allow event subscriptions with URLs to other networks The UPnP Device Architecture 2.0 specification errata ("UDA errata 16-04-2020.docx") addresses a problem with notifications being allowed to go out to other domains by disallowing such cases. Do such filtering for the notification callback URLs to avoid undesired connections to external networks based on subscriptions that any device in the local network could request when WPS support for external registrars is enabled (the upnp_iface parameter in hostapd configuration). Obtained from: https://w1.fi/security/2020-1/\ 0001-WPS-UPnP-Do-not-allow-event-subscriptions-with-URLs-.patch MFC after: 1 week Security: VU#339275 and CVE-2020-12695 --- src/wps/wps_er.c | 2 +- src/wps/wps_upnp.c | 38 ++++++++++++++++++++++++++++++++++++-- src/wps/wps_upnp_i.h | 3 ++- 3 files changed, 39 insertions(+), 4 deletions(-) diff --git a/src/wps/wps_er.c b/src/wps/wps_er.c index 06a8fdaf3459..b71fa718e096 100644 --- a/src/wps/wps_er.c +++ b/src/wps/wps_er.c @@ -1298,7 +1298,7 @@ wps_er_init(struct wps_context *wps, const char *ifname, const char *filter) "with %s", filter); } if (get_netif_info(er->ifname, &er->ip_addr, &er->ip_addr_text, - er->mac_addr)) { + NULL, er->mac_addr)) { wpa_printf(MSG_INFO, "WPS UPnP: Could not get IP/MAC address " "for %s. Does it have IP address?", er->ifname); wps_er_deinit(er, NULL, NULL); diff --git a/src/wps/wps_upnp.c b/src/wps/wps_upnp.c index ca893a43c64b..9e40aeb0dc97 100644 --- a/src/wps/wps_upnp.c +++ b/src/wps/wps_upnp.c @@ -303,6 +303,14 @@ static void subscr_addr_free_all(struct subscription *s) } +static int local_network_addr(struct upnp_wps_device_sm *sm, + struct sockaddr_in *addr) +{ + return (addr->sin_addr.s_addr & sm->netmask.s_addr) == + (sm->ip_addr & sm->netmask.s_addr); +} + + /* subscr_addr_add_url -- add address(es) for one url to subscription */ static void subscr_addr_add_url(struct subscription *s, const char *url, size_t url_len) @@ -381,6 +389,7 @@ static void subscr_addr_add_url(struct subscription *s, const char *url, for (rp = result; rp; rp = rp->ai_next) { struct subscr_addr *a; + struct sockaddr_in *addr = (struct sockaddr_in *) rp->ai_addr; /* Limit no. of address to avoid denial of service attack */ if (dl_list_len(&s->addr_list) >= MAX_ADDR_PER_SUBSCRIPTION) { @@ -389,6 +398,13 @@ static void subscr_addr_add_url(struct subscription *s, const char *url, break; } + if (!local_network_addr(s->sm, addr)) { + wpa_printf(MSG_INFO, + "WPS UPnP: Ignore a delivery URL that points to another network %s", + inet_ntoa(addr->sin_addr)); + continue; + } + a = os_zalloc(sizeof(*a) + alloc_len); if (a == NULL) break; @@ -889,11 +905,12 @@ static int eth_get(const char *device, u8 ea[ETH_ALEN]) * @net_if: Selected network interface name * @ip_addr: Buffer for returning IP address in network byte order * @ip_addr_text: Buffer for returning a pointer to allocated IP address text + * @netmask: Buffer for returning netmask or %NULL if not needed * @mac: Buffer for returning MAC address * Returns: 0 on success, -1 on failure */ int get_netif_info(const char *net_if, unsigned *ip_addr, char **ip_addr_text, - u8 mac[ETH_ALEN]) + struct in_addr *netmask, u8 mac[ETH_ALEN]) { struct ifreq req; int sock = -1; @@ -919,6 +936,19 @@ int get_netif_info(const char *net_if, unsigned *ip_addr, char **ip_addr_text, in_addr.s_addr = *ip_addr; os_snprintf(*ip_addr_text, 16, "%s", inet_ntoa(in_addr)); + if (netmask) { + os_memset(&req, 0, sizeof(req)); + os_strlcpy(req.ifr_name, net_if, sizeof(req.ifr_name)); + if (ioctl(sock, SIOCGIFNETMASK, &req) < 0) { + wpa_printf(MSG_ERROR, + "WPS UPnP: SIOCGIFNETMASK failed: %d (%s)", + errno, strerror(errno)); + goto fail; + } + addr = (struct sockaddr_in *) &req.ifr_netmask; + netmask->s_addr = addr->sin_addr.s_addr; + } + #ifdef __linux__ os_strlcpy(req.ifr_name, net_if, sizeof(req.ifr_name)); if (ioctl(sock, SIOCGIFHWADDR, &req) < 0) { @@ -1025,11 +1055,15 @@ static int upnp_wps_device_start(struct upnp_wps_device_sm *sm, char *net_if) /* Determine which IP and mac address we're using */ if (get_netif_info(net_if, &sm->ip_addr, &sm->ip_addr_text, - sm->mac_addr)) { + &sm->netmask, sm->mac_addr)) { wpa_printf(MSG_INFO, "WPS UPnP: Could not get IP/MAC address " "for %s. Does it have IP address?", net_if); goto fail; } + wpa_printf(MSG_DEBUG, "WPS UPnP: Local IP address %s netmask %s hwaddr " + MACSTR, + sm->ip_addr_text, inet_ntoa(sm->netmask), + MAC2STR(sm->mac_addr)); /* Listen for incoming TCP connections so that others * can fetch our "xml files" from us. diff --git a/src/wps/wps_upnp_i.h b/src/wps/wps_upnp_i.h index 6a7c627253e3..1359416fb239 100644 --- a/src/wps/wps_upnp_i.h +++ b/src/wps/wps_upnp_i.h @@ -128,6 +128,7 @@ struct upnp_wps_device_sm { u8 mac_addr[ETH_ALEN]; /* mac addr of network i.f. we use */ char *ip_addr_text; /* IP address of network i.f. we use */ unsigned ip_addr; /* IP address of network i.f. we use (host order) */ + struct in_addr netmask; int multicast_sd; /* send multicast messages over this socket */ int ssdp_sd; /* receive discovery UPD packets on socket */ int ssdp_sd_registered; /* nonzero if we must unregister */ @@ -158,7 +159,7 @@ struct subscription * subscription_find(struct upnp_wps_device_sm *sm, const u8 uuid[UUID_LEN]); void subscr_addr_delete(struct subscr_addr *a); int get_netif_info(const char *net_if, unsigned *ip_addr, char **ip_addr_text, - u8 mac[ETH_ALEN]); + struct in_addr *netmask, u8 mac[ETH_ALEN]); /* wps_upnp_ssdp.c */ void msearchreply_state_machine_stop(struct advertisement_state_machine *a);