dot11decrypt: Support decrypting FT initial mobility domain
Add partial support for decrypting captures with connections established using FT BSS Transition (IEEE 802.11r). FT BSS Transition decryption comes with the following limitations: - Only FT-PSK is supported. - Keys can only be derived from the FT 4-way handshake messages. - Roaming is not supported.
This commit is contained in:
Mikael Kanstrup
Wireshark GitLab Utility
parent
75e90aa4e9
commit
2306cbddb9
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@ -1472,6 +1472,19 @@ Dot11DecryptWepMng(
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return DOT11DECRYPT_RET_SUCCESS;
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}
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/* From IEEE 802.11-2016 Table 9-133—AKM suite selectors */
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static gboolean Dot11DecryptIsFtAkm(int akm)
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{
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switch (akm) {
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case 3:
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case 4:
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case 9:
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case 13:
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return TRUE;
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}
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return FALSE;
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}
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/* Refer to IEEE 802.11i-2004, 8.5.3, pag. 85 */
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static INT
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Dot11DecryptRsna4WHandshake(
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@ -1621,14 +1634,54 @@ Dot11DecryptRsna4WHandshake(
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return DOT11DECRYPT_RET_NO_VALID_HANDSHAKE;
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}
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/* derive the PTK from the BSSID, STA MAC, PMK, SNonce, ANonce */
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Dot11DecryptDerivePtk(sa, /* authenticator nonce, bssid, station mac */
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tmp_pkt_key->KeyData.Wpa.Psk, /* PSK == PMK */
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tmp_pkt_key->KeyData.Wpa.PskLen,
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eapol_parsed->nonce, /* supplicant nonce */
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eapol_parsed->key_version,
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akm,
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cipher);
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if (Dot11DecryptIsFtAkm(akm)) {
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int hash_algo = Dot11DecryptGetHashAlgoFromAkm(akm);
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guint8 pmk_r0[DOT11DECRYPT_WPA_PMK_MAX_LEN];
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guint8 pmk_r1[DOT11DECRYPT_WPA_PMK_MAX_LEN];
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guint8 pmk_r0_name[16];
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guint8 pmk_r1_name[16];
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guint8 ptk_name[16];
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size_t pmk_r0_len;
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size_t pmk_r1_len;
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size_t ptk_len = Dot11DecryptGetPtkLen(akm, cipher) / 8;
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if (!eapol_parsed->mdid || !eapol_parsed->r0kh_id || !eapol_parsed->r1kh_id) {
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DEBUG_PRINT_LINE("Fields missing for FT", DEBUG_LEVEL_3);
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return DOT11DECRYPT_RET_NO_VALID_HANDSHAKE;
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}
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/* TODO Handle other AKMS (xxkey == PSK is only valid for FT PSK) */
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dot11decrypt_derive_pmk_r0(tmp_pkt_key->KeyData.Wpa.Psk,
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tmp_pkt_key->KeyData.Wpa.PskLen,
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ctx->pkt_ssid, ctx->pkt_ssid_len,
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eapol_parsed->mdid,
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eapol_parsed->r0kh_id, eapol_parsed->r0kh_id_len,
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id->sta, hash_algo,
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pmk_r0, &pmk_r0_len, pmk_r0_name);
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DEBUG_DUMP("PMK-R0", pmk_r0, pmk_r0_len);
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DEBUG_DUMP("PMKR0Name", pmk_r0_name, 16);
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dot11decrypt_derive_pmk_r1(pmk_r0, pmk_r0_len, pmk_r0_name,
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eapol_parsed->r1kh_id, id->sta, hash_algo,
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pmk_r1, &pmk_r1_len, pmk_r1_name);
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DEBUG_DUMP("PMK-R1", pmk_r1, pmk_r1_len);
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DEBUG_DUMP("PMKR1Name", pmk_r1_name, 16);
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dot11decrypt_derive_ft_ptk(pmk_r1, pmk_r1_len, pmk_r1_name,
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eapol_parsed->nonce, sa->wpa.nonce,
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id->bssid, id->sta, hash_algo,
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sa->wpa.ptk, ptk_len, ptk_name);
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DEBUG_DUMP("PTK", sa->wpa.ptk, ptk_len);
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} else {
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/* derive the PTK from the BSSID, STA MAC, PMK, SNonce, ANonce */
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Dot11DecryptDerivePtk(sa, /* authenticator nonce, bssid, station mac */
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tmp_pkt_key->KeyData.Wpa.Psk, /* PSK == PMK */
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tmp_pkt_key->KeyData.Wpa.PskLen,
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eapol_parsed->nonce, /* supplicant nonce */
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eapol_parsed->key_version,
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akm,
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cipher);
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}
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DEBUG_DUMP("TK", DOT11DECRYPT_GET_TK(sa->wpa.ptk, akm), Dot11DecryptGetTkLen(cipher) / 8);
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ret = Dot11DecryptRsnaMicCheck(eapol_parsed,
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@ -161,6 +161,13 @@ typedef struct _DOT11DECRYPT_EAPOL_PARSED {
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guint16 mic_len;
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guint8 *gtk;
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guint16 gtk_len;
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/* For fast bss transition akms */
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guint8 *mdid;
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guint8 *r0kh_id;
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guint8 r0kh_id_len;
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guint8 *r1kh_id;
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guint8 r1kh_id_len;
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} DOT11DECRYPT_EAPOL_PARSED, *PDOT11DECRYPT_EAPOL_PARSED;
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/************************************************************************/
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@ -210,6 +210,188 @@ dot11decrypt_kdf(const guint8 *key, size_t key_len,
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return TRUE;
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}
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static gboolean sha256(const guint8 *data, size_t len, guint8 output[32])
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{
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gcry_md_hd_t ctx;
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gcry_error_t result = gcry_md_open(&ctx, GCRY_MD_SHA256, 0);
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guint8 *digest;
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if (result) {
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return FALSE;
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}
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gcry_md_write(ctx, data, len);
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digest = gcry_md_read(ctx, GCRY_MD_SHA256);
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if (!digest) {
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return FALSE;
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}
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memcpy(output, digest, 32);
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gcry_md_close(ctx);
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return TRUE;
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}
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/**
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* Derive PMK-R0 and PMKR0Name. See IEEE 802.11-2016 12.7.1.7.3 PMK-R0
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*
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* @param xxkey PSK / MPMK or certain part of MSK.
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* @param xxkey_len Length of xxkey in bytes.
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* @param ssid SSID
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* @param ssid_len Length of SSID in bytes.
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* @param mdid MDID (Mobility Domain Identifier).
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* @param r0kh_id PMK-R0 key holder identifier in the Authenticator.
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* @param r0kh_id_len Lenth of r0kh_id in bytes.
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* @param s0kh_id PMK-R0 key holder in the Supplicant (STA mac address)
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* @param s0kd_id_len Length of s0kh_id in bytes.
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* @param hash_algo Hash algorithm to use for the KDF.
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* See gcrypt available hash algorithms:
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* https://gnupg.org/documentation/manuals/gcrypt/Available-hash-algorithms.html
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* @param[out] pmk_r0 Pairwise master key, first level
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* @param[out] pmk_r0_name Pairwise master key (PMK) R0 name.
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*/
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gboolean
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dot11decrypt_derive_pmk_r0(const guint8 *xxkey, size_t xxkey_len,
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const guint8 *ssid, size_t ssid_len,
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const guint8 mdid[2],
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const guint8 *r0kh_id, size_t r0kh_id_len,
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const guint8 s0kh_id[DOT11DECRYPT_MAC_LEN],
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int hash_algo,
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guint8 *pmk_r0,
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size_t *pmk_r0_len,
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guint8 pmk_r0_name[16])
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{
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const char *ft_r0n = "FT-R0N";
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const size_t ft_r0n_len = strlen(ft_r0n);
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guint8 context[MAX_CONTEXT_LEN];
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guint8 r0_key_data[DOT11DECRYPT_WPA_PMK_MAX_LEN + 16];
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guint8 sha256_res[32];
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size_t offset = 0;
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guint q = gcry_md_get_algo_dlen(hash_algo);
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guint16 mdid_le = GUINT16_TO_LE(*(guint16*)mdid);
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if (!xxkey || !ssid || !mdid || !r0kh_id || !s0kh_id ||
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!pmk_r0 || !pmk_r0_len || !pmk_r0_name)
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{
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return FALSE;
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}
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if (1 + ssid_len + 2 + 1 + r0kh_id_len + DOT11DECRYPT_MAC_LEN > MAX_CONTEXT_LEN)
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{
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DEBUG_PRINT_LINE("Invalid input sizes", DEBUG_LEVEL_3);
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return FALSE;
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}
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// R0-Key-Data =
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// KDF-Hash-Length(XXKey, "FT-R0",
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// SSIDlength || SSID || MDID || R0KHlength || R0KH-ID || S0KH-ID)
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// PMK-R0 = L(R0-Key-Data, 0, Q) * PMK-R0Name-Salt = L(R0-Key-Data, Q, 128)
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context[offset++] = (guint8)ssid_len;
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memcpy(context + offset, ssid, ssid_len);
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offset += ssid_len;
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memcpy(context + offset, &mdid_le, 2);
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offset += 2;
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context[offset++] = (guint8)r0kh_id_len;
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memcpy(context + offset, r0kh_id, r0kh_id_len);
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offset += r0kh_id_len;
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memcpy(context + offset, s0kh_id, DOT11DECRYPT_MAC_LEN);
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offset += DOT11DECRYPT_MAC_LEN;
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dot11decrypt_kdf(xxkey, xxkey_len, "FT-R0", context, offset, hash_algo,
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r0_key_data, q + 16);
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memcpy(pmk_r0, r0_key_data, q);
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*pmk_r0_len = q;
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// PMK-R0Name-Salt = L(R0-Key-Data, Q, 128)
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// PMKR0Name = Truncate-128(SHA-256("FT-R0N" || PMK-R0Name-Salt))
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offset = 0;
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memcpy(context + offset, ft_r0n, ft_r0n_len);
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offset += ft_r0n_len;
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memcpy(context + offset, r0_key_data + q, 16);
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offset += 16;
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sha256(context, offset, sha256_res);
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memcpy(pmk_r0_name, sha256_res, 16);
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return TRUE;
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}
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/**
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* Derive PMK-R1 and PMKR1Name. See IEEE 802.11-2016 12.7.1.7.4 PMK-R1
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*
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*/
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gboolean
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dot11decrypt_derive_pmk_r1(const guint8 *pmk_r0, size_t pmk_r0_len,
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const guint8 *pmk_r0_name,
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const guint8 *r1kh_id, const guint8 *s1kh_id,
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int hash_algo,
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guint8 *pmk_r1, size_t *pmk_r1_len,
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guint8 *pmk_r1_name)
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{
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const char *ft_r1n = "FT-R1N";
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const size_t ft_r1n_len = strlen(ft_r1n);
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// context len = MAX(R1KH-ID || S1KH-ID, “FT-R1N” || PMKR0Name || R1KH-ID || S1KH-ID)
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guint8 context[6 + 16 + 6 + 6];
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guint8 sha256_res[32];
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size_t offset = 0;
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if (!pmk_r0 || !pmk_r0_name || !r1kh_id || !s1kh_id ||
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!pmk_r1 || !pmk_r1_len || !pmk_r1_name)
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{
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return FALSE;
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}
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*pmk_r1_len = gcry_md_get_algo_dlen(hash_algo);
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// PMK-R1 = KDF-Hash-Length(PMK-R0, "FT-R1", R1KH-ID || S1KH-ID)
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memcpy(context + offset, r1kh_id, DOT11DECRYPT_MAC_LEN);
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offset += DOT11DECRYPT_MAC_LEN;
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memcpy(context + offset, s1kh_id, DOT11DECRYPT_MAC_LEN);
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offset += DOT11DECRYPT_MAC_LEN;
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dot11decrypt_kdf(pmk_r0, pmk_r0_len, "FT-R1", context, offset, hash_algo,
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pmk_r1, *pmk_r1_len);
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// PMKR1Name = Truncate-128(SHA-256(“FT-R1N” || PMKR0Name || R1KH-ID || S1KH-ID))
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offset = 0;
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memcpy(context + offset, ft_r1n, ft_r1n_len);
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offset += ft_r1n_len;
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memcpy(context + offset, pmk_r0_name, 16);
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offset += 16;
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memcpy(context + offset, r1kh_id, DOT11DECRYPT_MAC_LEN);
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offset += DOT11DECRYPT_MAC_LEN;
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memcpy(context + offset, s1kh_id, DOT11DECRYPT_MAC_LEN);
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offset += DOT11DECRYPT_MAC_LEN;
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sha256(context, offset, sha256_res);
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memcpy(pmk_r1_name, sha256_res, 16);
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return TRUE;
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}
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/**
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* Derive PTK for FT AKMS. See IEE 802.11-2016 12.7.1.7.5 PTK
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*
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* PTK = KDF-Hash-Length(PMK-R1, "FT-PTK", SNonce || ANonce || BSSID || STA-ADDR)
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* PTKName = Truncate-128(
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* SHA-256(PMKR1Name || “FT-PTKN” || SNonce || ANonce || BSSID || STA-ADDR))
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*/
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gboolean
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dot11decrypt_derive_ft_ptk(const guint8 *pmk_r1, size_t pmk_r1_len,
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const guint8 *pmk_r1_name _U_,
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const guint8 *snonce, const guint8 *anonce,
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const guint8 *bssid, const guint8 *sta_addr,
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int hash_algo,
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guint8 *ptk, const size_t ptk_len, guint8 *ptk_name _U_)
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{
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guint8 context[32 + 32 + 6 + 6];
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guint offset = 0;
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// PTK = KDF-Hash-Length(PMK-R1, "FT-PTK", SNonce || ANonce || BSSID || STA-ADDR)
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memcpy(context + offset, snonce, 32);
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offset += 32;
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memcpy(context + offset, anonce, 32);
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offset += 32;
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memcpy(context + offset, bssid, DOT11DECRYPT_MAC_LEN);
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offset += DOT11DECRYPT_MAC_LEN;
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memcpy(context + offset, sta_addr, DOT11DECRYPT_MAC_LEN);
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offset += DOT11DECRYPT_MAC_LEN;
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dot11decrypt_kdf(pmk_r1, pmk_r1_len, "FT-PTK", context, offset, hash_algo,
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ptk, ptk_len);
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// TODO derive PTKName
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return TRUE;
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}
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/*
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* Editor modelines
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*
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@ -32,6 +32,32 @@ dot11decrypt_kdf(const guint8 *key, size_t key_len,
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int hash_algo,
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guint8 *output, size_t output_len);
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gboolean
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dot11decrypt_derive_pmk_r0(const guint8 *xxkey, size_t xxkey_len,
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const guint8 *ssid, size_t ssid_len,
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const guint8 mdid[2],
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const guint8 *r0kh_id, size_t r0kh_id_len,
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const guint8 s0kh_id[DOT11DECRYPT_MAC_LEN],
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int hash_algo,
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guint8 *pmk_r0,
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size_t *pmk_r0_len,
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guint8 pmk_r0_name[16]);
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gboolean
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dot11decrypt_derive_pmk_r1(const guint8 *pmk_r0, size_t pmk_r0_len,
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const guint8 *pmk_r0_name,
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const guint8 *r1kh_id, const guint8 *s1kh_id,
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int hash_algo,
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guint8 *pmk_r1, size_t *pmk_r1_len,
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guint8 *pmk_r1_name);
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gboolean
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dot11decrypt_derive_ft_ptk(const guint8 *pmk_r1, size_t pmk_r1_len,
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const guint8 *pmk_r1_name,
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const guint8 *snonce, const guint8 *anonce,
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const guint8 *bssid, const guint8 *sta_addr,
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int hash_algo,
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guint8 *ptk, size_t ptk_len, guint8 *ptk_name);
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#endif /* _DOT11DECRYPT_UTIL_H */
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/*
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@ -284,6 +284,11 @@ typedef struct mimo_control
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#define KEY_DATA_LEN_KEY 18
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#define GTK_KEY 19
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#define GTK_LEN_KEY 20
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#define MDID_KEY 21
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#define FTE_R0KH_ID_KEY 22
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#define FTE_R0KH_ID_LEN_KEY 23
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#define FTE_R1KH_ID_KEY 24
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#define FTE_R1KH_ID_LEN_KEY 25
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/* ************************************************************************* */
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/* Define some very useful macros that are used to analyze frame types etc. */
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@ -16424,6 +16429,7 @@ dissect_mobility_domain(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, voi
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return 1;
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}
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save_proto_data(tvb, pinfo, offset, 2, MDID_KEY);
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proto_tree_add_item(tree, hf_ieee80211_tag_mobility_domain_mdid,
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tvb, offset, 2, ENC_LITTLE_ENDIAN);
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proto_tree_add_item(tree, hf_ieee80211_tag_mobility_domain_ft_capab,
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@ -16616,6 +16622,8 @@ dissect_fast_bss_transition(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
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s_end = offset + len;
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switch (id) {
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case 1:
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save_proto_data(tvb, pinfo, offset, len, FTE_R1KH_ID_KEY);
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save_proto_data_value(pinfo, len, FTE_R1KH_ID_LEN_KEY);
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proto_tree_add_item(tree, hf_ieee80211_tag_ft_subelem_r1kh_id,
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tvb, offset, len, ENC_NA);
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break;
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@ -16641,6 +16649,8 @@ dissect_fast_bss_transition(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
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tvb, offset, s_end - offset, ENC_NA);
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break;
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case 3:
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save_proto_data(tvb, pinfo, offset, len, FTE_R0KH_ID_KEY);
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save_proto_data_value(pinfo, len, FTE_R0KH_ID_LEN_KEY);
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proto_tree_add_item(tree, hf_ieee80211_tag_ft_subelem_r0kh_id,
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tvb, offset, len, ENC_NA);
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break;
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@ -27612,6 +27622,17 @@ get_eapol_parsed(packet_info *pinfo, PDOT11DECRYPT_EAPOL_PARSED eapol_parsed)
|
|||
eapol_parsed->gtk = (guint8 *)p_get_proto_data(pinfo->pool, pinfo, proto_wlan, GTK_KEY);
|
||||
eapol_parsed->gtk_len = (guint16)
|
||||
GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, proto_wlan, GTK_LEN_KEY));
|
||||
|
||||
/* For fast bss transition akms */
|
||||
eapol_parsed->mdid = (guint8 *)p_get_proto_data(pinfo->pool, pinfo, proto_wlan, MDID_KEY);
|
||||
eapol_parsed->r0kh_id =
|
||||
(guint8 *)p_get_proto_data(pinfo->pool, pinfo, proto_wlan, FTE_R0KH_ID_KEY);
|
||||
eapol_parsed->r0kh_id_len = (guint8)
|
||||
GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, proto_wlan, FTE_R0KH_ID_LEN_KEY));
|
||||
eapol_parsed->r1kh_id =
|
||||
(guint8 *)p_get_proto_data(pinfo->pool, pinfo, proto_wlan, FTE_R1KH_ID_KEY);
|
||||
eapol_parsed->r1kh_id_len = (guint8)
|
||||
GPOINTER_TO_UINT(p_get_proto_data(pinfo->pool, pinfo, proto_wlan, FTE_R1KH_ID_LEN_KEY));
|
||||
}
|
||||
|
||||
static void
|
||||
|
|
|
|||
Binary file not shown.
|
|
@ -223,6 +223,17 @@ class case_decrypt_80211(subprocesstest.SubprocessTestCase):
|
|||
self.assertTrue(self.grepOutput('DHCP Request')) # Verifies TK is correct
|
||||
self.assertTrue(self.grepOutput(r'Echo \(ping\) request')) # Verifies TK is correct
|
||||
|
||||
def test_80211_wpa2_ft_psk(self, cmd_tshark, capture_file):
|
||||
'''IEEE 802.11 decode WPA2 FT PSK'''
|
||||
# Included in git sources test/captures/wpa2-ft-psk.pcapng.gz
|
||||
self.assertRun((cmd_tshark,
|
||||
'-o', 'wlan.enable_decryption: TRUE',
|
||||
'-r', capture_file('wpa2-ft-psk.pcapng.gz'),
|
||||
'-Y', 'wlan.analysis.tk == 58f564fd078c3cc8ceb8c8be8e51d30d || wlan.analysis.gtk == a2e4ae32e73603f12ecbce89992de9df',
|
||||
))
|
||||
self.assertTrue(self.grepOutput('DHCP Request')) # Verifies GTK decryption
|
||||
self.assertTrue(self.grepOutput(r'Echo \(ping\) request')) # Verifies TK decryption
|
||||
|
||||
@fixtures.mark_usefixtures('test_env_80211_user_tk')
|
||||
@fixtures.uses_fixtures
|
||||
class case_decrypt_80211_user_tk(subprocesstest.SubprocessTestCase):
|
||||
|
|
|
|||
Loading…
Reference in New Issue