src/cyw43_ll: parse RSN/WPA IEs in wifi scans results

Add a function (cyw43_ll_wifi_parse_ie_auth) to parse the
vendor-specific WPA IEs and RSN IEs received during wifi scans.

Define a more complete set of security and authentication flags and
redefine the CYW43_AUTH_ macros in terms of these new flags.

Return the AP security and authentication capabilities as a 32 bit field
in cyw43_ev_scan_result_t.auth_mode (previously an 8 bit field). Note
that this change may break compatibility with drivers that use the scan
feature.

Signed-off-by: Ricardo Cañuelo Navarro <rcn@igalia.com>

Author: r-c-n

src/cyw43_ll.c

@@ -263,6 +263,13 @@ static void cyw43_xxd(size_t len, const uint8_t *buf) {
 #define DOT11_IE_ID_RSN               (48)
 #define DOT11_IE_ID_VENDOR_SPECIFIC   (221)
 #define WPA_OUI_TYPE1                 "\x00\x50\xF2\x01"
+#define IEEE_802_11_OUI               "\x00\x0F\xAC"
+#define IEEE_802_11_OUI_LEN           3
+
+// Field offsets for authentication (RSN/WPA) IEs
+#define IE_AUTH_GROUP_CIPHER_OUI_OFFSET      4
+#define IE_AUTH_GROUP_CIPHER_OFFSET          7
+#define IE_AUTH_PAIRWISE_CIPHER_COUNT_OFFSET 8
 
 #define SLEEP_MAX (50)
 
@@ -535,6 +542,148 @@ static inline uint16_t cyw43_be16toh(uint16_t x) {
     return (x >> 8) | (x << 8);
 }
 
+/* IEEE 802.11 AKM suites */
+typedef enum
+{
+    AKM_RESERVED,
+    AKM_8021X,        /* WPA2 enterprise                 */
+    AKM_PSK,          /* WPA2 PSK                        */
+    AKM_FT_8021X,     /* 802.11r Fast Roaming enterprise */
+    AKM_FT_PSK,       /* 802.11r Fast Roaming PSK        */
+    AKM_8021X_SHA256,
+    AKM_PSK_SHA256,
+    AKM_TDLS,         /* Tunneled Direct Link Setup      */
+    AKM_SAE_SHA256,
+    AKM_FT_SAE_SHA256,
+    AKM_AP_PEER_KEY_SHA256,
+    AKM_SUITEB_8021X_HMAC_SHA256,
+    AKM_SUITEB_8021X_HMAC_SHA384,
+    AKM_SUITEB_FT_8021X_HMAC_SHA384,
+} akm_suite_t;
+
+/* IEEE 802.11 Cipher suites */
+typedef enum
+{
+    CIPHER_GROUP,            /* Use group cipher suite                               */
+    CIPHER_WEP_40,           /* WEP-40                                               */
+    CIPHER_TKIP,             /* TKIP                                                 */
+    CIPHER_RESERVED,         /* Reserved                                             */
+    CIPHER_CCMP_128,         /* CCMP-128 - default pairwise and group cipher suite   */
+    CIPHER_WEP_104,          /* WEP-104 - also known as WEP-128                      */
+    CIPHER_BIP_CMAC_128,     /* BIP-CMAC-128 - default management frame cipher suite */
+    CIPHER_GROUP_DISALLOWED, /* Group address traffic not allowed                    */
+    CIPHER_GCMP_128,         /* GCMP-128 - default for 60 GHz STAs                   */
+    CIPHER_GCMP_256,         /* GCMP-256 - introduced for Suite B                    */
+    CIPHER_CCMP_256,         /* CCMP-256 - introduced for suite B                    */
+    CIPHER_BIP_GMAC_128,     /* BIP-GMAC-128 - introduced for suite B                */
+    CIPHER_BIP_GMAC_256,     /* BIP-GMAC-256 - introduced for suite B                */
+    CIPHER_BIP_CMAC_256,     /* BIP-CMAC-256 - introduced for suite B                */
+} cipher_t;
+
+/*
+ * Parses an RSN or vendor-specific WPA IE.
+ *
+ * Parameters:
+ *   ie: the buffer containing the Information Element.
+ *   wpa: 1 if the IE is a vendor-specific WPA IE, 0 if it's an RSN IE.
+ *
+ * Returns the security and authentication capabilities encoded in a
+ * 32-bit field (see the CYW43_AUTH_ macros), or 0 if it found an error
+ * parsing the IE.
+ */
+static uint32_t cyw43_ll_wifi_parse_ie_auth(uint8_t *ie, int wpa) {
+    uint32_t security = 0;
+    char *oui;
+    int pairwise_cipher_cnt;
+    int akm_cnt;
+    int idx;
+
+    if (wpa) {
+        security = WPA_SECURITY;
+        oui = WPA_OUI_TYPE1;
+    } else {
+        oui = IEEE_802_11_OUI;
+    }
+
+    /* Group cipher suite */
+    if (memcmp(&ie[IE_AUTH_GROUP_CIPHER_OUI_OFFSET], oui, IEEE_802_11_OUI_LEN)) {
+        return 0;
+    }
+    switch (ie[IE_AUTH_GROUP_CIPHER_OFFSET]) {
+    case CIPHER_TKIP:
+        security |= TKIP_ENABLED;
+        break;
+    case CIPHER_CCMP_128:
+        security |= AES_ENABLED;
+        break;
+    default:
+        CYW43_WARN("Unsupported group cipher %d\n", ie[IE_AUTH_GROUP_CIPHER_OFFSET]);
+    }
+
+    /* Pairwise cipher suites */
+    pairwise_cipher_cnt = *(uint16_t*)(&ie[IE_AUTH_PAIRWISE_CIPHER_COUNT_OFFSET]);
+    idx = IE_AUTH_PAIRWISE_CIPHER_COUNT_OFFSET + 2;
+    for (int i = 0; i < pairwise_cipher_cnt; i++) {
+        if (memcmp(&ie[idx], oui, IEEE_802_11_OUI_LEN)) {
+            CYW43_WARN("Error parsing management IE: wrong OUI in pairwise cipher\n");
+            return 0;
+        }
+        idx += IEEE_802_11_OUI_LEN;
+        switch (ie[idx]) {
+        case CIPHER_TKIP:
+            security |= TKIP_ENABLED;
+            break;
+        case CIPHER_CCMP_128:
+            security |= AES_ENABLED;
+            break;
+        default:
+            CYW43_WARN("Unsupported pairwise cipher %d\n", ie[idx]);
+        }
+        idx++;
+    }
+
+    /* AKM suites */
+    akm_cnt = *(uint16_t*)(&ie[idx]);
+    idx += 2;
+    for (int i = 0; i < akm_cnt; i++) {
+        if (memcmp(&ie[idx], oui, IEEE_802_11_OUI_LEN)) {
+            CYW43_WARN("Error parsing management IE: wrong OUI in AKM suite\n");
+            return 0;
+        }
+        idx += IEEE_802_11_OUI_LEN;
+        switch (ie[idx]) {
+        case AKM_PSK:
+            security |= WPA2_SECURITY;
+            break;
+        case AKM_PSK_SHA256:
+            security |= WPA2_SECURITY | WPA2_SHA256_SECURITY;
+            break;
+        case AKM_SAE_SHA256:
+            security |= WPA3_SECURITY;
+            break;
+        case AKM_8021X:
+            if (wpa) {
+                security |= ENTERPRISE_ENABLED;
+            } else {
+                security |= WPA2_SECURITY | ENTERPRISE_ENABLED;
+            }
+            break;
+        case AKM_FT_8021X:
+            security |= WPA2_SECURITY | FBT_ENABLED | ENTERPRISE_ENABLED;
+            break;
+        case AKM_FT_PSK:
+            security |= WPA2_SECURITY | FBT_ENABLED;
+            break;
+        default:
+            CYW43_WARN("Unsupported group cipher %d\n", ie_rsn[idx]);
+        }
+        idx++;
+    }
+
+    return security;
+}
+
+
 static void cyw43_ll_wifi_parse_scan_result(cyw43_async_event_t *ev) {
     struct _scan_result_t {
         uint32_t buflen;
@@ -572,15 +721,13 @@ static void cyw43_ll_wifi_parse_scan_result(cyw43_async_event_t *ev) {
     }
     int security = 0;// OPEN
     if (ie_rsn != NULL) {
-        // TODO need to parse the IE to check for TKIP, AES and enterprise modes
-        security |= 4;// WPA2;
+        security = cyw43_ll_wifi_parse_ie_auth(ie_rsn, 0);
     }
     if (ie_wpa != NULL) {
-        // TODO need to parse the IE to check for TKIP, AES and enterprise modes
-        security |= 2;// WPA;
+        security = cyw43_ll_wifi_parse_ie_auth(ie_wpa, 1);
     }
     if (scan_res->bss.capability & DOT11_CAP_PRIVACY) {
-        security |= 1;// WEP_PSK;
+        security |= WEP_ENABLED;
     }
 
     ev->u.scan_result.channel &= 0xff;

src/cyw43_ll.h

@@ -161,18 +161,33 @@
 #define CYW43_REASON_SUP_DEAUTH             (14)    // received FC_DEAUTH
 #define CYW43_REASON_SUP_WPA_PSK_TMO        (15)    // WPA PSK 4-way handshake timeout
 
+// Security and authentication flags
+#define WEP_ENABLED              0x0001
+#define TKIP_ENABLED             0x0002
+#define AES_ENABLED              0x0004
+#define SHARED_ENABLED       0x00008000
+#define WPA_SECURITY         0x00200000
+#define WPA2_SECURITY        0x00400000
+#define WPA2_SHA256_SECURITY 0x00800000
+#define WPA3_SECURITY        0x01000000
+#define ENTERPRISE_ENABLED   0x02000000
+#define WPS_ENABLED          0x10000000
+#define IBSS_ENABLED         0x20000000
+#define FBT_ENABLED          0x40000000
+
 /**
  * \name Authorization types
  * \brief Used when setting up an access point, or connecting to an access point
  * \anchor CYW43_AUTH_
  */
 //!\{
-#define CYW43_AUTH_OPEN (0)                     ///< No authorisation required (open)
-#define CYW43_AUTH_WPA_TKIP_PSK   (0x00200002)  ///< WPA authorisation
-#define CYW43_AUTH_WPA2_AES_PSK   (0x00400004)  ///< WPA2 authorisation (preferred)
-#define CYW43_AUTH_WPA2_MIXED_PSK (0x00400006)  ///< WPA2/WPA mixed authorisation
-#define CYW43_AUTH_WPA3_SAE_AES_PSK  (0x01000004)   ///< WPA3 AES authorisation
-#define CYW43_AUTH_WPA3_WPA2_AES_PSK (0x01400004)   ///< WPA2/WPA3 authorisation
+#define CYW43_AUTH_OPEN              (0)                                           ///< No authorisation required (open)
+#define CYW43_AUTH_WEP_PSK           (WEP_ENABLED)                                 ///< WEP PSK Security with open authentication
+#define CYW43_AUTH_WPA_TKIP_PSK      (WPA_SECURITY | TKIP_ENABLED)                 ///< WPA authorisation
+#define CYW43_AUTH_WPA2_AES_PSK      (WPA2_SECURITY | AES_ENABLED)                 ///< WPA2 authorisation (preferred)
+#define CYW43_AUTH_WPA2_MIXED_PSK    (WPA2_SECURITY | AES_ENABLED | TKIP_ENABLED)  ///< WPA2/WPA mixed authorisation
+#define CYW43_AUTH_WPA3_SAE_AES_PSK  (WPA3_SECURITY | AES_ENABLED)                 ///< WPA3 AES authorisation
+#define CYW43_AUTH_WPA3_WPA2_AES_PSK (WPA3_SECURITY | WPA2_SECURITY | AES_ENABLED) ///< WPA2/WPA3 authorisation
 //!\}
 
 /*!
@@ -221,9 +236,10 @@ typedef struct _cyw43_ev_scan_result_t {
     uint8_t ssid[32];   ///< wlan access point name
     uint32_t _2[5];
     uint16_t channel;   ///< wifi channel
-    uint16_t _3;
-    uint8_t auth_mode;  ///< wifi auth mode \ref CYW43_AUTH_
+    uint8_t _3[3];
     int16_t rssi;       ///< signal strength
+    uint8_t _4[7];
+    uint32_t auth_mode; ///< security and authentication flags
 } cyw43_ev_scan_result_t;
 //!\}