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https://git.kernel.org/pub/scm/network/wireless/iwd.git
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eapol: WPA-specific handshake quirks
To support WPA allow the legacy EAPOL-Key frame formats.
This commit is contained in:
Andrew Zaborowski
Denis Kenzior
parent
a8c0f20510
commit
a7846aee85
212
src/eapol.c
212
src/eapol.c
@ -305,7 +305,7 @@ bool eapol_verify_ptk_2_of_4(const struct eapol_key *ek)
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return true;
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}
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bool eapol_verify_ptk_3_of_4(const struct eapol_key *ek)
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bool eapol_verify_ptk_3_of_4(const struct eapol_key *ek, bool is_wpa)
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{
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uint16_t key_len;
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@ -318,10 +318,11 @@ bool eapol_verify_ptk_3_of_4(const struct eapol_key *ek)
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if (!ek->key_mic)
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return false;
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if (!ek->secure)
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if (ek->secure != !is_wpa)
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return false;
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if (!ek->encrypted_key_data)
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/* Must be encrypted when GTK is present but reserved in WPA */
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if (!ek->encrypted_key_data && !is_wpa)
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return false;
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key_len = L_BE16_TO_CPU(ek->key_length);
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@ -338,7 +339,7 @@ bool eapol_verify_ptk_3_of_4(const struct eapol_key *ek)
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return true;
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}
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bool eapol_verify_ptk_4_of_4(const struct eapol_key *ek)
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bool eapol_verify_ptk_4_of_4(const struct eapol_key *ek, bool is_wpa)
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{
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uint16_t key_len;
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@ -351,10 +352,10 @@ bool eapol_verify_ptk_4_of_4(const struct eapol_key *ek)
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if (!ek->key_mic)
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return false;
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if (!ek->secure)
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if (ek->secure != !is_wpa)
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return false;
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if (ek->encrypted_key_data)
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if (ek->encrypted_key_data && !is_wpa)
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return false;
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key_len = L_BE16_TO_CPU(ek->key_length);
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@ -421,7 +422,8 @@ static struct eapol_key *eapol_create_common(
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const uint8_t snonce[],
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size_t extra_len,
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const uint8_t *extra_data,
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int key_type)
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int key_type,
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bool is_wpa)
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{
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size_t to_alloc = sizeof(struct eapol_key);
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struct eapol_key *out_frame = l_malloc(to_alloc + extra_len);
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@ -431,7 +433,8 @@ static struct eapol_key *eapol_create_common(
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out_frame->protocol_version = protocol;
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out_frame->packet_type = 0x3;
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out_frame->packet_len = L_CPU_TO_BE16(to_alloc + extra_len - 4);
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out_frame->descriptor_type = EAPOL_DESCRIPTOR_TYPE_80211;
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out_frame->descriptor_type = is_wpa ? EAPOL_DESCRIPTOR_TYPE_WPA :
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EAPOL_DESCRIPTOR_TYPE_80211;
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out_frame->key_descriptor_version = version;
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out_frame->key_type = key_type;
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out_frame->install = false;
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@ -457,35 +460,41 @@ struct eapol_key *eapol_create_ptk_2_of_4(
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uint64_t key_replay_counter,
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const uint8_t snonce[],
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size_t extra_len,
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const uint8_t *extra_data)
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const uint8_t *extra_data,
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bool is_wpa)
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{
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return eapol_create_common(protocol, version, false, key_replay_counter,
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snonce, extra_len, extra_data, 1);
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snonce, extra_len, extra_data, 1,
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is_wpa);
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}
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struct eapol_key *eapol_create_ptk_4_of_4(
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enum eapol_protocol_version protocol,
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enum eapol_key_descriptor_version version,
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uint64_t key_replay_counter)
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uint64_t key_replay_counter,
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bool is_wpa)
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{
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uint8_t snonce[32];
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memset(snonce, 0, sizeof(snonce));
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return eapol_create_common(protocol, version, true, key_replay_counter,
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snonce, 0, NULL, 1);
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return eapol_create_common(protocol, version,
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is_wpa ? false : true,
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key_replay_counter, snonce, 0, NULL,
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1, is_wpa);
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}
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static struct eapol_key *eapol_create_gtk_2_of_2(
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struct eapol_key *eapol_create_gtk_2_of_2(
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enum eapol_protocol_version protocol,
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enum eapol_key_descriptor_version version,
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uint64_t key_replay_counter)
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uint64_t key_replay_counter,
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bool is_wpa)
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{
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uint8_t snonce[32];
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memset(snonce, 0, sizeof(snonce));
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return eapol_create_common(protocol, version, true,
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key_replay_counter, snonce, 0, NULL,
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0);
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0, is_wpa);
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}
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struct eapol_sm {
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@ -503,6 +512,7 @@ struct eapol_sm {
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struct l_timeout *timeout;
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bool have_snonce:1;
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bool have_replay:1;
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bool ptk_complete:1;
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bool wpa_ie:1;
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};
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@ -674,7 +684,8 @@ static void eapol_handle_ptk_1_of_4(uint32_t ifindex, struct eapol_sm *sm,
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ek->key_descriptor_version,
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sm->replay_counter,
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sm->snonce,
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sm->own_ie[1] + 2, sm->own_ie);
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sm->own_ie[1] + 2, sm->own_ie,
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sm->wpa_ie);
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if (!eapol_calculate_mic(ptk->kck, step2, mic)) {
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l_info("MIC calculation failed. "
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@ -741,13 +752,31 @@ static const uint8_t *eapol_find_rsne(const uint8_t *data, size_t data_len)
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return NULL;
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}
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static const uint8_t *eapol_find_wpa_ie(const uint8_t *data, size_t data_len)
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{
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struct ie_tlv_iter iter;
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ie_tlv_iter_init(&iter, data, data_len);
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while (ie_tlv_iter_next(&iter)) {
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if (ie_tlv_iter_get_tag(&iter) != IE_TYPE_VENDOR_SPECIFIC)
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continue;
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if (is_ie_wpa_ie(ie_tlv_iter_get_data(&iter),
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ie_tlv_iter_get_length(&iter)))
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return ie_tlv_iter_get_data(&iter) - 2;
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}
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return NULL;
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}
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/*
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* This function performs a match of the RSN IE obtained from the scan
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* results vs the RSN IE obtained as part of the 4-way handshake. If they
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* This function performs a match of the RSN/WPA IE obtained from the scan
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* results vs the RSN/WPA IE obtained as part of the 4-way handshake. If they
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* don't match, the EAPoL packet must be silently discarded.
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*/
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static bool eapol_ap_rsne_matches(const uint8_t *eapol_rsne,
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const uint8_t *scan_rsne)
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static bool eapol_ap_ie_matches(const uint8_t *eapol_ie,
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const uint8_t *scan_ie, bool is_wpa)
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{
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struct ie_rsn_info eapol_info;
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struct ie_rsn_info scan_info;
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@ -756,21 +785,31 @@ static bool eapol_ap_rsne_matches(const uint8_t *eapol_rsne,
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* First check that the sizes match, if they do, run a bitwise
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* comparison.
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*/
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if (eapol_rsne[1] == scan_rsne[1] &&
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!memcmp(eapol_rsne + 2, scan_rsne + 2, eapol_rsne[1]))
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if (eapol_ie[1] == scan_ie[1] &&
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!memcmp(eapol_ie + 2, scan_ie + 2, eapol_ie[1]))
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return true;
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/*
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* Otherwise we have to parse the RSN IEs and compare the individual
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* Otherwise we have to parse the IEs and compare the individual
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* fields
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*/
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if (ie_parse_rsne_from_data(eapol_rsne, eapol_rsne[1] + 2,
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&eapol_info) < 0)
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return false;
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if (!is_wpa) {
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if (ie_parse_rsne_from_data(eapol_ie, eapol_ie[1] + 2,
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&eapol_info) < 0)
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return false;
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if (ie_parse_rsne_from_data(scan_rsne, scan_rsne[1] + 2,
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&scan_info) < 0)
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return false;
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if (ie_parse_rsne_from_data(scan_ie, scan_ie[1] + 2,
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&scan_info) < 0)
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return false;
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} else {
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if (ie_parse_wpa_from_data(eapol_ie, eapol_ie[1] + 2,
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&eapol_info) < 0)
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return false;
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if (ie_parse_wpa_from_data(scan_ie, scan_ie[1] + 2,
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&scan_info) < 0)
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return false;
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}
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if (eapol_info.group_cipher != scan_info.group_cipher)
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return false;
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@ -838,7 +877,7 @@ static void eapol_handle_ptk_3_of_4(uint32_t ifindex,
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const uint8_t *rsne;
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uint8_t gtk_key_index;
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if (!eapol_verify_ptk_3_of_4(ek)) {
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if (!eapol_verify_ptk_3_of_4(ek, sm->wpa_ie)) {
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handshake_failed(ifindex, sm, MPDU_REASON_CODE_UNSPECIFIED);
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return;
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}
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@ -857,13 +896,18 @@ static void eapol_handle_ptk_3_of_4(uint32_t ifindex,
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* not identical to that the STA received in the Beacon or Probe
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* Response frame, the STA shall disassociate.
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*/
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rsne = eapol_find_rsne(decrypted_key_data, decrypted_key_data_size);
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if (!sm->wpa_ie)
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rsne = eapol_find_rsne(decrypted_key_data,
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decrypted_key_data_size);
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else
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rsne = eapol_find_wpa_ie(decrypted_key_data,
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decrypted_key_data_size);
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if (!rsne) {
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handshake_failed(ifindex, sm, MPDU_REASON_CODE_IE_DIFFERENT);
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return;
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}
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if (!eapol_ap_rsne_matches(rsne, sm->ap_ie)) {
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if (!eapol_ap_ie_matches(rsne, sm->ap_ie, sm->wpa_ie)) {
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handshake_failed(ifindex, sm, MPDU_REASON_CODE_IE_DIFFERENT);
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return;
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}
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@ -878,22 +922,27 @@ static void eapol_handle_ptk_3_of_4(uint32_t ifindex,
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/*
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* TODO: If group_cipher was negotiated, find the GTK and install it
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*/
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gtk = eapol_find_gtk_kde(decrypted_key_data, decrypted_key_data_size,
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>k_len);
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if (!gtk || gtk_len < 2) {
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handshake_failed(ifindex, sm, MPDU_REASON_CODE_UNSPECIFIED);
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return;
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}
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if (!sm->wpa_ie) {
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gtk = eapol_find_gtk_kde(decrypted_key_data,
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decrypted_key_data_size,
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>k_len);
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if (!gtk || gtk_len < 8) {
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handshake_failed(ifindex, sm,
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MPDU_REASON_CODE_UNSPECIFIED);
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return;
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}
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gtk_key_index = util_bit_field(gtk[0], 0, 2);
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/* TODO: Handle tx bit */
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/* TODO: Handle tx bit */
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gtk += 2;
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gtk_len -= 2;
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gtk_key_index = util_bit_field(gtk[0], 0, 2);
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gtk += 2;
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gtk_len -= 2;
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} else
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gtk = NULL;
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step4 = eapol_create_ptk_4_of_4(protocol_version,
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ek->key_descriptor_version,
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sm->replay_counter);
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sm->replay_counter, sm->wpa_ie);
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/*
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* 802.11-2012, Section 11.6.6.4, step b):
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@ -907,10 +956,12 @@ static void eapol_handle_ptk_3_of_4(uint32_t ifindex,
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memcpy(step4->key_mic_data, mic, sizeof(mic));
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tx_packet(ifindex, sm->aa, sm->spa, step4, user_data);
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sm->ptk_complete = true;
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if (install_tk)
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install_tk(sm->ifindex, sm->aa, ptk->tk, rsne, sm->user_data);
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if (install_gtk)
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if (gtk && install_gtk)
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install_gtk(sm->ifindex, gtk_key_index, gtk, gtk_len,
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ek->key_rsc, 6, rsne, sm->user_data);
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@ -937,20 +988,31 @@ static void eapol_handle_gtk_1_of_2(uint32_t ifindex,
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return;
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}
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gtk = eapol_find_gtk_kde(decrypted_key_data,
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decrypted_key_data_size,
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>k_len);
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if (!sm->wpa_ie) {
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gtk = eapol_find_gtk_kde(decrypted_key_data,
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decrypted_key_data_size,
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>k_len);
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if (!gtk || gtk_len < 8)
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return;
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if (!gtk || gtk_len < 8)
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return;
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} else {
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gtk = decrypted_key_data;
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gtk_len = decrypted_key_data_size;
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gtk_key_index = util_bit_field(gtk[0], 0, 2);
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gtk += 2;
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gtk_len -= 2;
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if (!gtk || gtk_len < 6)
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return;
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}
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if (!sm->wpa_ie) {
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gtk_key_index = util_bit_field(gtk[0], 0, 2);
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gtk += 2;
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gtk_len -= 2;
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} else
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gtk_key_index = ek->wpa_key_id;
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step2 = eapol_create_gtk_2_of_2(protocol_version,
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ek->key_descriptor_version,
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sm->replay_counter);
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sm->replay_counter, sm->wpa_ie);
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/*
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* 802.11-2012, Section 11.6.7.3, step b):
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@ -1006,7 +1068,7 @@ void __eapol_rx_packet(uint32_t ifindex, const uint8_t *spa, const uint8_t *aa,
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struct eapol_sm *sm;
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struct crypto_ptk *ptk;
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uint8_t *decrypted_key_data = NULL;
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size_t decrypted_key_data_len;
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size_t key_data_len = 0;
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uint64_t replay_counter;
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ek = eapol_key_validate(frame, len);
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@ -1021,6 +1083,12 @@ void __eapol_rx_packet(uint32_t ifindex, const uint8_t *spa, const uint8_t *aa,
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if (!ek->key_ack)
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return;
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/* Further Descriptor Type check */
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if (!sm->wpa_ie && ek->descriptor_type != EAPOL_DESCRIPTOR_TYPE_80211)
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return;
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else if (sm->wpa_ie && ek->descriptor_type != EAPOL_DESCRIPTOR_TYPE_WPA)
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return;
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replay_counter = L_BE64_TO_CPU(ek->key_replay_counter);
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/*
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@ -1049,33 +1117,47 @@ void __eapol_rx_packet(uint32_t ifindex, const uint8_t *spa, const uint8_t *aa,
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return;
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}
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if (ek->encrypted_key_data) {
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if ((ek->encrypted_key_data && !sm->wpa_ie) ||
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(ek->key_type == 0 && sm->wpa_ie)) {
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/* Haven't received step 1 yet, so no ptk */
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if (!sm->have_snonce)
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return;
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decrypted_key_data = eapol_decrypt_key_data(ptk->kek, ek,
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&decrypted_key_data_len);
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&key_data_len);
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if (!decrypted_key_data)
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return;
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}
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} else
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key_data_len = L_BE16_TO_CPU(ek->key_data_len);
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/* Check if this is the group key handshake */
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if (ek->key_type == 0) {
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if (!ek->key_mic || !ek->secure)
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/* Only GTK handshake allowed after PTK handshake complete */
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if (!sm->ptk_complete)
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goto done;
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eapol_handle_gtk_1_of_2(ifindex, sm, ek, decrypted_key_data,
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decrypted_key_data_len, user_data);
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if (!decrypted_key_data)
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goto done;
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eapol_handle_gtk_1_of_2(ifindex, sm, ek,
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decrypted_key_data,
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key_data_len, user_data);
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goto done;
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}
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/* If no MIC, then assume packet 1, otherwise packet 3 */
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if (!ek->key_mic)
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eapol_handle_ptk_1_of_4(ifindex, sm, ek, user_data);
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else
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eapol_handle_ptk_3_of_4(ifindex, sm, ek, decrypted_key_data,
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decrypted_key_data_len, user_data);
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else {
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if (sm->ptk_complete)
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goto done;
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if (!key_data_len)
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goto done;
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eapol_handle_ptk_3_of_4(ifindex, sm, ek,
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decrypted_key_data ?: ek->key_data,
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key_data_len, user_data);
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}
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done:
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l_free(decrypted_key_data);
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16
src/eapol.h
16
src/eapol.h
@ -123,8 +123,8 @@ const struct eapol_key *eapol_key_validate(const uint8_t *frame, size_t len);
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bool eapol_verify_ptk_1_of_4(const struct eapol_key *ek);
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bool eapol_verify_ptk_2_of_4(const struct eapol_key *ek);
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bool eapol_verify_ptk_3_of_4(const struct eapol_key *ek);
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bool eapol_verify_ptk_4_of_4(const struct eapol_key *ek);
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bool eapol_verify_ptk_3_of_4(const struct eapol_key *ek, bool is_wpa);
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bool eapol_verify_ptk_4_of_4(const struct eapol_key *ek, bool is_wpa);
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bool eapol_verify_gtk_1_of_2(const struct eapol_key *ek, bool is_wpa);
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struct eapol_key *eapol_create_ptk_2_of_4(
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@ -133,12 +133,20 @@ struct eapol_key *eapol_create_ptk_2_of_4(
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uint64_t key_replay_counter,
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const uint8_t snonce[],
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size_t extra_len,
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const uint8_t *extra_data);
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const uint8_t *extra_data,
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bool is_wpa);
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struct eapol_key *eapol_create_ptk_4_of_4(
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enum eapol_protocol_version protocol,
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enum eapol_key_descriptor_version version,
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uint64_t key_replay_counter);
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uint64_t key_replay_counter,
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bool is_wpa);
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struct eapol_key *eapol_create_gtk_2_of_2(
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enum eapol_protocol_version protocol,
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enum eapol_key_descriptor_version version,
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uint64_t key_replay_counter,
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bool is_wpa);
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void __eapol_rx_packet(uint32_t ifindex, const uint8_t *spa, const uint8_t *aa,
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const uint8_t *frame, size_t len,
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