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Reduce the amount of time PTK/TPTK/GTK is kept in memory

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Some of the buffers used to keep a copy of PTK/TPTK/GTK in the
supplicant implementation maintained a copy of the keys longer than
necessary. Clear these buffers to zero when the key is not needed
anymore to minimize the amount of time key material is kept in memory.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2014-04-16 01:27:10 +03:00
parent 2a354dc06f
commit d2c33b91ad
1 changed files with 36 additions and 22 deletions
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42
src/rsn_supp/wpa.c
View file

@ -383,7 +383,6 @@ static void wpa_supplicant_process_1_of_4(struct wpa_sm *sm,
{ {
struct wpa_eapol_ie_parse ie; struct wpa_eapol_ie_parse ie;
struct wpa_ptk *ptk; struct wpa_ptk *ptk;
u8 buf[8];
int res; int res;
u8 *kde, *kde_buf = NULL; u8 *kde, *kde_buf = NULL;
size_t kde_len; size_t kde_len;
@ -438,10 +437,12 @@ static void wpa_supplicant_process_1_of_4(struct wpa_sm *sm,
ptk = &sm->tptk; ptk = &sm->tptk;
wpa_derive_ptk(sm, src_addr, key, ptk); wpa_derive_ptk(sm, src_addr, key, ptk);
if (sm->pairwise_cipher == WPA_CIPHER_TKIP) { if (sm->pairwise_cipher == WPA_CIPHER_TKIP) {
u8 buf[8];
/* Supplicant: swap tx/rx Mic keys */ /* Supplicant: swap tx/rx Mic keys */
os_memcpy(buf, ptk->u.auth.tx_mic_key, 8); os_memcpy(buf, ptk->u.auth.tx_mic_key, 8);
os_memcpy(ptk->u.auth.tx_mic_key, ptk->u.auth.rx_mic_key, 8); os_memcpy(ptk->u.auth.tx_mic_key, ptk->u.auth.rx_mic_key, 8);
os_memcpy(ptk->u.auth.rx_mic_key, buf, 8); os_memcpy(ptk->u.auth.rx_mic_key, buf, 8);
os_memset(buf, 0, sizeof(buf));
} }
sm->tptk_set = 1; sm->tptk_set = 1;
@ -657,6 +658,7 @@ static int wpa_supplicant_install_gtk(struct wpa_sm *sm,
wpa_msg(sm->ctx->msg_ctx, MSG_WARNING, wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
"WPA: Failed to set GTK to the driver " "WPA: Failed to set GTK to the driver "
"(Group only)"); "(Group only)");
os_memset(gtk_buf, 0, sizeof(gtk_buf));
return -1; return -1;
} }
} else if (wpa_sm_set_key(sm, gd->alg, broadcast_ether_addr, } else if (wpa_sm_set_key(sm, gd->alg, broadcast_ether_addr,
@ -666,8 +668,10 @@ static int wpa_supplicant_install_gtk(struct wpa_sm *sm,
"WPA: Failed to set GTK to " "WPA: Failed to set GTK to "
"the driver (alg=%d keylen=%d keyidx=%d)", "the driver (alg=%d keylen=%d keyidx=%d)",
gd->alg, gd->gtk_len, gd->keyidx); gd->alg, gd->gtk_len, gd->keyidx);
os_memset(gtk_buf, 0, sizeof(gtk_buf));
return -1; return -1;
} }
os_memset(gtk_buf, 0, sizeof(gtk_buf));
return 0; return 0;
} }
@ -729,8 +733,10 @@ static int wpa_supplicant_pairwise_gtk(struct wpa_sm *sm,
wpa_supplicant_install_gtk(sm, &gd, key->key_rsc))) { wpa_supplicant_install_gtk(sm, &gd, key->key_rsc))) {
wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG,
"RSN: Failed to install GTK"); "RSN: Failed to install GTK");
os_memset(&gd, 0, sizeof(gd));
return -1; return -1;
} }
os_memset(&gd, 0, sizeof(gd));
wpa_supplicant_key_neg_complete(sm, sm->bssid, wpa_supplicant_key_neg_complete(sm, sm->bssid,
key_info & WPA_KEY_INFO_SECURE); key_info & WPA_KEY_INFO_SECURE);
@ -1237,7 +1243,6 @@ static int wpa_supplicant_process_1_of_2_wpa(struct wpa_sm *sm,
struct wpa_gtk_data *gd) struct wpa_gtk_data *gd)
{ {
size_t maxkeylen; size_t maxkeylen;
u8 ek[32];
gd->gtk_len = WPA_GET_BE16(key->key_length); gd->gtk_len = WPA_GET_BE16(key->key_length);
maxkeylen = keydatalen; maxkeylen = keydatalen;
@ -1266,20 +1271,23 @@ static int wpa_supplicant_process_1_of_2_wpa(struct wpa_sm *sm,
gd->keyidx = (key_info & WPA_KEY_INFO_KEY_INDEX_MASK) >> gd->keyidx = (key_info & WPA_KEY_INFO_KEY_INDEX_MASK) >>
WPA_KEY_INFO_KEY_INDEX_SHIFT; WPA_KEY_INFO_KEY_INDEX_SHIFT;
if (ver == WPA_KEY_INFO_TYPE_HMAC_MD5_RC4) { if (ver == WPA_KEY_INFO_TYPE_HMAC_MD5_RC4) {
os_memcpy(ek, key->key_iv, 16); u8 ek[32];
os_memcpy(ek + 16, sm->ptk.kek, 16);
if (keydatalen > sizeof(gd->gtk)) { if (keydatalen > sizeof(gd->gtk)) {
wpa_msg(sm->ctx->msg_ctx, MSG_WARNING, wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
"WPA: RC4 key data too long (%lu)", "WPA: RC4 key data too long (%lu)",
(unsigned long) keydatalen); (unsigned long) keydatalen);
return -1; return -1;
} }
os_memcpy(ek, key->key_iv, 16);
os_memcpy(ek + 16, sm->ptk.kek, 16);
os_memcpy(gd->gtk, key + 1, keydatalen); os_memcpy(gd->gtk, key + 1, keydatalen);
if (rc4_skip(ek, 32, 256, gd->gtk, keydatalen)) { if (rc4_skip(ek, 32, 256, gd->gtk, keydatalen)) {
os_memset(ek, 0, sizeof(ek));
wpa_msg(sm->ctx->msg_ctx, MSG_ERROR, wpa_msg(sm->ctx->msg_ctx, MSG_ERROR,
"WPA: RC4 failed"); "WPA: RC4 failed");
return -1; return -1;
} }
os_memset(ek, 0, sizeof(ek));
} else if (ver == WPA_KEY_INFO_TYPE_HMAC_SHA1_AES) { } else if (ver == WPA_KEY_INFO_TYPE_HMAC_SHA1_AES) {
if (keydatalen % 8) { if (keydatalen % 8) {
wpa_msg(sm->ctx->msg_ctx, MSG_WARNING, wpa_msg(sm->ctx->msg_ctx, MSG_WARNING,
@ -1430,6 +1438,7 @@ static int wpa_supplicant_verify_eapol_key_mic(struct wpa_sm *sm,
sm->tptk_set = 0; sm->tptk_set = 0;
sm->ptk_set = 1; sm->ptk_set = 1;
os_memcpy(&sm->ptk, &sm->tptk, sizeof(sm->ptk)); os_memcpy(&sm->ptk, &sm->tptk, sizeof(sm->ptk));
os_memset(&sm->tptk, 0, sizeof(sm->tptk));
} }
} }
@ -1482,10 +1491,12 @@ static int wpa_supplicant_decrypt_key_data(struct wpa_sm *sm,
os_memcpy(ek, key->key_iv, 16); os_memcpy(ek, key->key_iv, 16);
os_memcpy(ek + 16, sm->ptk.kek, 16); os_memcpy(ek + 16, sm->ptk.kek, 16);
if (rc4_skip(ek, 32, 256, (u8 *) (key + 1), keydatalen)) { if (rc4_skip(ek, 32, 256, (u8 *) (key + 1), keydatalen)) {
os_memset(ek, 0, sizeof(ek));
wpa_msg(sm->ctx->msg_ctx, MSG_ERROR, wpa_msg(sm->ctx->msg_ctx, MSG_ERROR,
"WPA: RC4 failed"); "WPA: RC4 failed");
return -1; return -1;
} }
os_memset(ek, 0, sizeof(ek));
} else if (ver == WPA_KEY_INFO_TYPE_HMAC_SHA1_AES || } else if (ver == WPA_KEY_INFO_TYPE_HMAC_SHA1_AES ||
ver == WPA_KEY_INFO_TYPE_AES_128_CMAC || ver == WPA_KEY_INFO_TYPE_AES_128_CMAC ||
sm->key_mgmt == WPA_KEY_MGMT_OSEN) { sm->key_mgmt == WPA_KEY_MGMT_OSEN) {
@ -2133,7 +2144,9 @@ void wpa_sm_notify_assoc(struct wpa_sm *sm, const u8 *bssid)
*/ */
wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, "WPA: Clear old PTK"); wpa_dbg(sm->ctx->msg_ctx, MSG_DEBUG, "WPA: Clear old PTK");
sm->ptk_set = 0; sm->ptk_set = 0;
os_memset(&sm->ptk, 0, sizeof(sm->ptk));
sm->tptk_set = 0; sm->tptk_set = 0;
os_memset(&sm->tptk, 0, sizeof(sm->tptk));
} }
#ifdef CONFIG_TDLS #ifdef CONFIG_TDLS
@ -2663,20 +2676,14 @@ void wpa_sm_pmksa_cache_flush(struct wpa_sm *sm, void *network_ctx)
#ifdef CONFIG_WNM #ifdef CONFIG_WNM
int wpa_wnmsleep_install_key(struct wpa_sm *sm, u8 subelem_id, u8 *buf) int wpa_wnmsleep_install_key(struct wpa_sm *sm, u8 subelem_id, u8 *buf)
{ {
struct wpa_gtk_data gd;
#ifdef CONFIG_IEEE80211W
struct wpa_igtk_kde igd;
u16 keyidx;
#endif /* CONFIG_IEEE80211W */
u16 keyinfo; u16 keyinfo;
u8 keylen; /* plaintext key len */ u8 keylen; /* plaintext key len */
u8 *key_rsc; u8 *key_rsc;
os_memset(&gd, 0, sizeof(gd)); if (subelem_id == WNM_SLEEP_SUBELEM_GTK) {
#ifdef CONFIG_IEEE80211W struct wpa_gtk_data gd;
os_memset(&igd, 0, sizeof(igd));
#endif /* CONFIG_IEEE80211W */
os_memset(&gd, 0, sizeof(gd));
keylen = wpa_cipher_key_len(sm->group_cipher); keylen = wpa_cipher_key_len(sm->group_cipher);
gd.key_rsc_len = wpa_cipher_rsc_len(sm->group_cipher); gd.key_rsc_len = wpa_cipher_rsc_len(sm->group_cipher);
gd.alg = wpa_cipher_to_alg(sm->group_cipher); gd.alg = wpa_cipher_to_alg(sm->group_cipher);
@ -2685,7 +2692,6 @@ int wpa_wnmsleep_install_key(struct wpa_sm *sm, u8 subelem_id, u8 *buf)
return -1; return -1;
} }
if (subelem_id == WNM_SLEEP_SUBELEM_GTK) {
key_rsc = buf + 5; key_rsc = buf + 5;
keyinfo = WPA_GET_LE16(buf + 2); keyinfo = WPA_GET_LE16(buf + 2);
gd.gtk_len = keylen; gd.gtk_len = keylen;
@ -2703,12 +2709,18 @@ int wpa_wnmsleep_install_key(struct wpa_sm *sm, u8 subelem_id, u8 *buf)
wpa_hexdump_key(MSG_DEBUG, "Install GTK (WNM SLEEP)", wpa_hexdump_key(MSG_DEBUG, "Install GTK (WNM SLEEP)",
gd.gtk, gd.gtk_len); gd.gtk, gd.gtk_len);
if (wpa_supplicant_install_gtk(sm, &gd, key_rsc)) { if (wpa_supplicant_install_gtk(sm, &gd, key_rsc)) {
os_memset(&gd, 0, sizeof(gd));
wpa_printf(MSG_DEBUG, "Failed to install the GTK in " wpa_printf(MSG_DEBUG, "Failed to install the GTK in "
"WNM mode"); "WNM mode");
return -1; return -1;
} }
os_memset(&gd, 0, sizeof(gd));
#ifdef CONFIG_IEEE80211W #ifdef CONFIG_IEEE80211W
} else if (subelem_id == WNM_SLEEP_SUBELEM_IGTK) { } else if (subelem_id == WNM_SLEEP_SUBELEM_IGTK) {
struct wpa_igtk_kde igd;
u16 keyidx;
os_memset(&igd, 0, sizeof(igd));
keylen = wpa_cipher_key_len(sm->mgmt_group_cipher); keylen = wpa_cipher_key_len(sm->mgmt_group_cipher);
os_memcpy(igd.keyid, buf + 2, 2); os_memcpy(igd.keyid, buf + 2, 2);
os_memcpy(igd.pn, buf + 4, 6); os_memcpy(igd.pn, buf + 4, 6);
@ -2724,8 +2736,10 @@ int wpa_wnmsleep_install_key(struct wpa_sm *sm, u8 subelem_id, u8 *buf)
igd.igtk, keylen) < 0) { igd.igtk, keylen) < 0) {
wpa_printf(MSG_DEBUG, "Failed to install the IGTK in " wpa_printf(MSG_DEBUG, "Failed to install the IGTK in "
"WNM mode"); "WNM mode");
os_memset(&igd, 0, sizeof(igd));
return -1; return -1;
} }
os_memset(&igd, 0, sizeof(igd));
#endif /* CONFIG_IEEE80211W */ #endif /* CONFIG_IEEE80211W */
} else { } else {
wpa_printf(MSG_DEBUG, "Unknown element id"); wpa_printf(MSG_DEBUG, "Unknown element id");