Additional consistentcy checks for PTK component lengths

Verify that TK, KCK, and KEK lengths are set to consistent values within
struct wpa_ptk before using them in supplicant. This is an additional
layer of protection against unexpected states.

Signed-off-by: Jouni Malinen <j@w1.fi>

diff --git a/src/common/wpa_common.c b/src/common/wpa_common.c
index f61a9088a2974d084f294b4daea276670bb71d8d..4bab6b9c159a17f5f80f6ff53bdbba84cfef3a8e 100644 (file)
--- a/src/common/wpa_common.c
+++ b/src/common/wpa_common.c
@@ -106,6 +106,12 @@ int wpa_eapol_key_mic(const u8 *key, size_t key_len, int akmp, int ver,
 {
        u8 hash[SHA512_MAC_LEN];
 
+       if (key_len == 0) {
+               wpa_printf(MSG_DEBUG,
+                          "WPA: KCK not set - cannot calculate MIC");
+               return -1;
+       }
+
        switch (ver) {
 #ifndef CONFIG_FIPS
        case WPA_KEY_INFO_TYPE_HMAC_MD5_RC4:

diff --git a/src/rsn_supp/wpa.c b/src/rsn_supp/wpa.c
index 0aed5bc746c077d04dbaf4ec185ad46d8d68e154..bfcd9c39809da87ecfb8b1ec59e2e6b9ab403cce 100644 (file)
--- a/src/rsn_supp/wpa.c
+++ b/src/rsn_supp/wpa.c
@@ -726,6 +726,11 @@ static int wpa_supplicant_install_ptk(struct wpa_sm *sm,
 
        alg = wpa_cipher_to_alg(sm->pairwise_cipher);
        keylen = wpa_cipher_key_len(sm->pairwise_cipher);
+       if (keylen <= 0 || (unsigned int) keylen != sm->ptk.tk_len) {
+               wpa_printf(MSG_DEBUG, "WPA: TK length mismatch: %d != %lu",
+                          keylen, (long unsigned int) sm->ptk.tk_len);
+               return -1;
+       }
        rsclen = wpa_cipher_rsc_len(sm->pairwise_cipher);
 
        if (sm->proto == WPA_PROTO_RSN || sm->proto == WPA_PROTO_OSEN) {
@@ -746,6 +751,7 @@ static int wpa_supplicant_install_ptk(struct wpa_sm *sm,
 
        /* TK is not needed anymore in supplicant */
        os_memset(sm->ptk.tk, 0, WPA_TK_MAX_LEN);
+       sm->ptk.tk_len = 0;
        sm->ptk.installed = 1;
 
        if (sm->wpa_ptk_rekey) {
@@ -1718,9 +1724,10 @@ static int wpa_supplicant_verify_eapol_key_mic(struct wpa_sm *sm,
        os_memcpy(mic, key + 1, mic_len);
        if (sm->tptk_set) {
                os_memset(key + 1, 0, mic_len);
-               wpa_eapol_key_mic(sm->tptk.kck, sm->tptk.kck_len, sm->key_mgmt,
-                                 ver, buf, len, (u8 *) (key + 1));
-               if (os_memcmp_const(mic, key + 1, mic_len) != 0) {
+               if (wpa_eapol_key_mic(sm->tptk.kck, sm->tptk.kck_len,
+                                     sm->key_mgmt,
+                                     ver, buf, len, (u8 *) (key + 1)) < 0 ||
+                   os_memcmp_const(mic, key + 1, mic_len) != 0) {
                        wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
                                "WPA: Invalid EAPOL-Key MIC "
                                "when using TPTK - ignoring TPTK");
@@ -1743,9 +1750,10 @@ static int wpa_supplicant_verify_eapol_key_mic(struct wpa_sm *sm,
 
        if (!ok && sm->ptk_set) {
                os_memset(key + 1, 0, mic_len);
-               wpa_eapol_key_mic(sm->ptk.kck, sm->ptk.kck_len, sm->key_mgmt,
-                                 ver, buf, len, (u8 *) (key + 1));
-               if (os_memcmp_const(mic, key + 1, mic_len) != 0) {
+               if (wpa_eapol_key_mic(sm->ptk.kck, sm->ptk.kck_len,
+                                     sm->key_mgmt,
+                                     ver, buf, len, (u8 *) (key + 1)) < 0 ||
+                   os_memcmp_const(mic, key + 1, mic_len) != 0) {
                        wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
                                "WPA: Invalid EAPOL-Key MIC - "
                                "dropping packet");
@@ -4123,6 +4131,11 @@ int fils_process_assoc_resp(struct wpa_sm *sm, const u8 *resp, size_t len)
 
        alg = wpa_cipher_to_alg(sm->pairwise_cipher);
        keylen = wpa_cipher_key_len(sm->pairwise_cipher);
+       if (keylen <= 0 || (unsigned int) keylen != sm->ptk.tk_len) {
+               wpa_printf(MSG_DEBUG, "FILS: TK length mismatch: %u != %lu",
+                          keylen, (long unsigned int) sm->ptk.tk_len);
+               goto fail;
+       }
        rsclen = wpa_cipher_rsc_len(sm->pairwise_cipher);
        wpa_hexdump_key(MSG_DEBUG, "FILS: Set TK to driver",
                        sm->ptk.tk, keylen);
@@ -4139,6 +4152,7 @@ int fils_process_assoc_resp(struct wpa_sm *sm, const u8 *resp, size_t len)
         * takes care of association frame encryption/decryption. */
        /* TK is not needed anymore in supplicant */
        os_memset(sm->ptk.tk, 0, WPA_TK_MAX_LEN);
+       sm->ptk.tk_len = 0;
        sm->ptk.installed = 1;
 
        /* FILS HLP Container */