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PEAP: Explicitly clear temporary keys from memory when using CMK

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The case of PEAPv0 with crypto binding did not clear some of the
temporary keys from stack/heap when those keys were not needed anymore.
Clear those explicitly to avoid unnecessary caching of keying material.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2019-02-02 00:01:29 +02:00
parent 4e1cd3468e
commit d05dda61d8
2 changed files with 18 additions and 8 deletions
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12
src/eap_peer/eap_peap.c
View file

@ -188,7 +188,7 @@ static void eap_peap_deinit(struct eap_sm *sm, void *priv)
os_free(data->session_id);
wpabuf_free(data->pending_phase2_req);
wpabuf_free(data->pending_resp);
os_free(data);
bin_clear_free(data, sizeof(*data));
}
@ -253,7 +253,7 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
{
u8 *tk;
u8 isk[32], imck[60];
int resumed;
int resumed, res;
/*
* Tunnel key (TK) is the first 60 octets of the key generated by
@ -292,9 +292,11 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
* in the end of the label just before ISK; is that just a typo?)
*/
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: TempKey", tk, 40);
if (peap_prfplus(data->peap_version, tk, 40,
res = peap_prfplus(data->peap_version, tk, 40,
"Inner Methods Compound Keys",
isk, sizeof(isk), imck, sizeof(imck)) < 0)
isk, sizeof(isk), imck, sizeof(imck));
os_memset(isk, 0, sizeof(isk));
if (res < 0)
return -1;
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: IMCK (IPMKj)",
imck, sizeof(imck));
@ -303,6 +305,7 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: IPMK (S-IPMKj)", data->ipmk, 40);
os_memcpy(data->cmk, imck + 40, 20);
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: CMK (CMKj)", data->cmk, 20);
os_memset(imck, 0, sizeof(imck));
return 0;
}
@ -1263,6 +1266,7 @@ static u8 * eap_peap_getKey(struct eap_sm *sm, void *priv, size_t *len)
os_memcpy(key, csk, EAP_TLS_KEY_LEN);
wpa_hexdump(MSG_DEBUG, "EAP-PEAP: Derived key",
key, EAP_TLS_KEY_LEN);
os_memset(csk, 0, sizeof(csk));
} else
os_memcpy(key, data->key_data, EAP_TLS_KEY_LEN);

10
src/eap_server/eap_server_peap.c
View file

@ -324,6 +324,7 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
{
u8 *tk;
u8 isk[32], imck[60];
int res;
/*
* Tunnel key (TK) is the first 60 octets of the key generated by
@ -358,9 +359,11 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
* in the end of the label just before ISK; is that just a typo?)
*/
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: TempKey", tk, 40);
if (peap_prfplus(data->peap_version, tk, 40,
res = peap_prfplus(data->peap_version, tk, 40,
"Inner Methods Compound Keys",
isk, sizeof(isk), imck, sizeof(imck)) < 0) {
isk, sizeof(isk), imck, sizeof(imck));
os_memset(isk, 0, sizeof(isk));
if (res < 0) {
os_free(tk);
return -1;
}
@ -373,6 +376,7 @@ static int eap_peap_derive_cmk(struct eap_sm *sm, struct eap_peap_data *data)
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: IPMK (S-IPMKj)", data->ipmk, 40);
os_memcpy(data->cmk, imck + 40, 20);
wpa_hexdump_key(MSG_DEBUG, "EAP-PEAP: CMK (CMKj)", data->cmk, 20);
os_memset(imck, 0, sizeof(imck));
return 0;
}
@ -1322,6 +1326,8 @@ static u8 * eap_peap_getKey(struct eap_sm *sm, void *priv, size_t *len)
"key");
}
os_memset(csk, 0, sizeof(csk));
return eapKeyData;
}