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eapol: More strictly validate key_descriptor_version

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This commit is contained in:
Denis Kenzior 2022-10-19 15:30:28 -05:00
parent 7f2aa40bba
commit b85b92b3ee
3 changed files with 74 additions and 16 deletions
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40
src/eapol.c
View File

@ -2238,12 +2238,14 @@ static void eapol_key_handle(struct eapol_sm *sm,
const struct eapol_frame *frame,
bool unencrypted)
{
struct handshake_state *hs = sm->handshake;
const struct eapol_key *ek;
const uint8_t *kck;
const uint8_t *kek;
uint8_t *decrypted_key_data = NULL;
size_t key_data_len = 0;
uint64_t replay_counter;
uint8_t expected_key_descriptor_version;
ek = eapol_key_validate((const uint8_t *) frame,
sizeof(struct eapol_header) +
@ -2256,11 +2258,19 @@ static void eapol_key_handle(struct eapol_sm *sm,
if (!ek->key_ack)
return;
/* Further Descriptor Type check */
if (!sm->handshake->wpa_ie &&
ek->descriptor_type != EAPOL_DESCRIPTOR_TYPE_80211)
if (L_WARN_ON(eapol_key_descriptor_version_from_akm(hs->akm_suite,
hs->pairwise_cipher,
&expected_key_descriptor_version) < 0))
return;
else if (sm->handshake->wpa_ie &&
if (L_WARN_ON(expected_key_descriptor_version !=
ek->key_descriptor_version))
return;
/* Further Descriptor Type check */
if (!hs->wpa_ie && ek->descriptor_type != EAPOL_DESCRIPTOR_TYPE_80211)
return;
else if (hs->wpa_ie &&
ek->descriptor_type != EAPOL_DESCRIPTOR_TYPE_WPA)
return;
@ -2293,31 +2303,30 @@ static void eapol_key_handle(struct eapol_sm *sm,
if (sm->have_replay && sm->replay_counter >= replay_counter)
return;
kck = handshake_state_get_kck(sm->handshake);
kck = handshake_state_get_kck(hs);
if (ek->key_mic) {
/* Haven't received step 1 yet, so no ptk */
if (!sm->handshake->have_snonce)
if (!hs->have_snonce)
return;
if (!eapol_verify_mic(sm->handshake->akm_suite, kck, ek,
sm->mic_len))
if (!eapol_verify_mic(hs->akm_suite, kck, ek, sm->mic_len))
return;
}
if ((ek->encrypted_key_data && !sm->handshake->wpa_ie) ||
(ek->key_type == 0 && sm->handshake->wpa_ie)) {
if ((ek->encrypted_key_data && !hs->wpa_ie) ||
(ek->key_type == 0 && hs->wpa_ie)) {
/*
* If using a MIC (non-FILS) but haven't received step 1 yet
* we disregard since there will be no ptk
*/
if (sm->mic_len && !sm->handshake->have_snonce)
if (sm->mic_len && !hs->have_snonce)
return;
kek = handshake_state_get_kek(sm->handshake);
kek = handshake_state_get_kek(hs);
decrypted_key_data = eapol_decrypt_key_data(
sm->handshake->akm_suite, kek,
hs->akm_suite, kek,
ek, &key_data_len, sm->mic_len);
if (!decrypted_key_data)
return;
@ -2326,11 +2335,10 @@ static void eapol_key_handle(struct eapol_sm *sm,
if (ek->key_type == 0) {
/* GTK handshake allowed only after PTK handshake complete */
if (!sm->handshake->ptk_complete)
if (!hs->ptk_complete)
goto done;
if (sm->handshake->group_cipher ==
IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC)
if (hs->group_cipher == IE_RSN_CIPHER_SUITE_NO_GROUP_TRAFFIC)
goto done;
if (!decrypted_key_data)

44
src/eapolutil.c
View File

@ -25,9 +25,11 @@
#endif
#include <stdio.h>
#include <errno.h>
#include <ell/ell.h>
#include "src/eapolutil.h"
#include "src/ie.h"
const struct eapol_key *eapol_key_validate(const uint8_t *frame, size_t len,
size_t mic_len)
@ -80,3 +82,45 @@ const struct eapol_key *eapol_key_validate(const uint8_t *frame, size_t len,
return ek;
}
int eapol_key_descriptor_version_from_akm(enum ie_rsn_akm_suite akm,
enum ie_rsn_cipher_suite pairwise,
uint8_t *outv)
{
/* 802.11-2020 Section 12.7.2 */
switch (akm) {
case IE_RSN_AKM_SUITE_8021X:
case IE_RSN_AKM_SUITE_PSK:
if (pairwise == IE_RSN_CIPHER_SUITE_USE_GROUP_CIPHER ||
pairwise == IE_RSN_CIPHER_SUITE_TKIP)
*outv = EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_MD5_ARC4;
else
*outv = EAPOL_KEY_DESCRIPTOR_VERSION_HMAC_SHA1_AES;
return 0;
case IE_RSN_AKM_SUITE_FT_OVER_8021X:
case IE_RSN_AKM_SUITE_FT_USING_PSK:
case IE_RSN_AKM_SUITE_8021X_SHA256:
case IE_RSN_AKM_SUITE_PSK_SHA256:
*outv = EAPOL_KEY_DESCRIPTOR_VERSION_AES_128_CMAC_AES;
return 0;
case IE_RSN_AKM_SUITE_SAE_SHA256:
case IE_RSN_AKM_SUITE_FT_OVER_SAE_SHA256:
case IE_RSN_AKM_SUITE_8021X_SUITE_B_SHA256:
case IE_RSN_AKM_SUITE_8021X_SUITE_B_SHA384:
case IE_RSN_AKM_SUITE_FT_OVER_8021X_SHA384:
case IE_RSN_AKM_SUITE_FILS_SHA256:
case IE_RSN_AKM_SUITE_FILS_SHA384:
case IE_RSN_AKM_SUITE_FT_OVER_FILS_SHA256:
case IE_RSN_AKM_SUITE_FT_OVER_FILS_SHA384:
case IE_RSN_AKM_SUITE_OWE:
case IE_RSN_AKM_SUITE_OSEN:
*outv = EAPOL_KEY_DESCRIPTOR_VERSION_AKM_DEFINED;
return 0;
case IE_RSN_AKM_SUITE_TDLS:
case IE_RSN_AKM_SUITE_AP_PEER_KEY_SHA256:
break;
}
return -ENOTSUP;
};

6
src/eapolutil.h
View File

@ -25,6 +25,9 @@
#include <asm/byteorder.h>
#include <linux/types.h>
enum ie_rsn_akm_suite;
enum ie_rsn_cipher_suite;
enum eapol_protocol_version {
EAPOL_PROTOCOL_VERSION_2001 = 1,
EAPOL_PROTOCOL_VERSION_2004 = 2,
@ -116,3 +119,6 @@ struct eapol_key {
const struct eapol_key *eapol_key_validate(const uint8_t *frame, size_t len,
size_t mic_len);
int eapol_key_descriptor_version_from_akm(enum ie_rsn_akm_suite akm,
enum ie_rsn_cipher_suite pairwise,
uint8_t *out_version);