static int check_frame_protection(struct candidate *cand, struct ieee80211_mgmt_frame *mgmt, int len, struct info_elems *elems)
{
unsigned char *clear_ampe_ie;
struct info_elems ies_parsed;
unsigned short ampe_ie_len, cat_to_mic_len;
int r;
unsigned int* key_expiration_p;
assert(len && cand && mgmt);
clear_ampe_ie = malloc(sizeof(struct ampe_ie) + 2);
if (!clear_ampe_ie) {
sae_debug(AMPE_DEBUG_KEYS, "Verify frame: out of memory\n");
return -1;
}
if (!elems->mic || elems->mic_len != MIC_IE_BODY_SIZE) {
sae_debug(AMPE_DEBUG_KEYS, "Verify frame: invalid MIC\n");
free(clear_ampe_ie);
return -1;
}
/*
* ampe_ie_len is the length of the ciphertext (the encrypted
* AMPE IE) and it needs to be inferred from the total frame
* size
*/
ampe_ie_len = len -
(elems->mic + elems->mic_len - (unsigned char *)mgmt);
/*
* cat_to_mic_len is the length of the contents of the frame
* from the category (inclusive) to the mic (exclusive)
*/
cat_to_mic_len = elems->mic - 2 - (unsigned char *) &mgmt->action;
r = siv_decrypt(&cand->sivctx, elems->mic + elems->mic_len,
clear_ampe_ie,
ampe_ie_len,
elems->mic, 3,
cand->peer_mac, ETH_ALEN,
cand->my_mac, ETH_ALEN,
&mgmt->action, cat_to_mic_len);
sae_debug(AMPE_DEBUG_KEYS, "Checking protection to " MACSTR " from " MACSTR "\n",
MAC2STR(cand->my_mac), MAC2STR(cand->peer_mac));
sae_debug(AMPE_DEBUG_KEYS, "Len checking cat-to-mic len:%d ampe ie full length: %d\n",
cat_to_mic_len, ampe_ie_len);
sae_hexdump(AMPE_DEBUG_KEYS, "SIV- Got AAD[3]: ", (unsigned char *) &mgmt->action,
cat_to_mic_len);
if (r != 1) {
sae_debug(AMPE_DEBUG_KEYS, "Protection check failed\n");
free(clear_ampe_ie);
return -1;
}
sae_hexdump(AMPE_DEBUG_KEYS, "AMPE IE: ", clear_ampe_ie, ampe_ie_len);
parse_ies(clear_ampe_ie, ampe_ie_len, &ies_parsed);
if (memcmp(ies_parsed.ampe->peer_nonce, null_nonce, 32) != 0 &&
memcmp(ies_parsed.ampe->peer_nonce, cand->my_nonce, 32) != 0) {
sae_hexdump(AMPE_DEBUG_KEYS, "IE peer_nonce ", ies_parsed.ampe->peer_nonce, 32);
sae_debug(AMPE_DEBUG_KEYS, "Unexpected nonce\n");
free(clear_ampe_ie);
return -1;
}
memcpy(cand->peer_nonce, ies_parsed.ampe->local_nonce, 32);
memcpy(cand->mgtk, ies_parsed.ampe->mgtk, sizeof(cand->mgtk));
sae_hexdump(AMPE_DEBUG_KEYS, "Received mgtk: ", cand->mgtk, sizeof(cand->mgtk));
key_expiration_p = (unsigned int *)ies_parsed.ampe->key_expiration;
cand->mgtk_expiration = le32toh(*key_expiration_p);
free(clear_ampe_ie);
return -1;
#undef MIC_IE_BODY_SIZE
}
static int check_frame_protection(struct candidate *cand, struct ieee80211_mgmt_frame *mgmt, int len, struct info_elems *elems)
{
unsigned char *clear_ampe_ie;
struct info_elems ies_parsed;
struct mesh_node *mesh = cand->conf->mesh;
unsigned short ampe_ie_len, cat_to_mic_len;
int r;
unsigned int* key_expiration_p;
u8 ftype = mgmt->action.action_code;
u8 *gtkdata, *igtkdata;
assert(len && cand && mgmt);
if (!elems->mic || elems->mic_len != MIC_IE_BODY_SIZE) {
sae_debug(AMPE_DEBUG_KEYS, "Verify frame: invalid MIC\n");
return -1;
}
/*
* ampe_ie_len is the length of the ciphertext (the encrypted
* AMPE IE) and it needs to be inferred from the total frame
* size
*/
ampe_ie_len = len -
(elems->mic + elems->mic_len - (unsigned char *)mgmt);
/* expect at least MGTK + RSC + expiry for open/confirm */
if (ftype != PLINK_CLOSE &&
ampe_ie_len < 2 + sizeof(struct ampe_ie) + 16 + 8 + 4) {
sae_debug(AMPE_DEBUG_KEYS, "Verify frame: AMPE IE too small\n");
return -1;
}
/* if PMF, then we also need IGTKData */
if (mesh->conf->pmf) {
if (ampe_ie_len < 2 + sizeof(struct ampe_ie) + 16 + 8 + 4 +
2 + 6 + 16 /* IGTKData */) {
sae_debug(AMPE_DEBUG_KEYS, "Verify frame: AMPE IE missing IGTK\n");
return -1;
}
}
clear_ampe_ie = malloc(ampe_ie_len);
if (!clear_ampe_ie) {
sae_debug(AMPE_DEBUG_KEYS, "Verify frame: out of memory\n");
return -1;
}
/*
* cat_to_mic_len is the length of the contents of the frame
* from the category (inclusive) to the mic (exclusive)
*/
cat_to_mic_len = elems->mic - 2 - (unsigned char *) &mgmt->action;
r = siv_decrypt(&cand->sivctx, elems->mic + elems->mic_len,
clear_ampe_ie,
ampe_ie_len,
elems->mic, 3,
cand->peer_mac, ETH_ALEN,
cand->my_mac, ETH_ALEN,
&mgmt->action, cat_to_mic_len);
sae_debug(AMPE_DEBUG_KEYS, "Checking protection to " MACSTR " from " MACSTR "\n",
MAC2STR(cand->my_mac), MAC2STR(cand->peer_mac));
sae_debug(AMPE_DEBUG_KEYS, "Len checking cat-to-mic len:%d ampe ie full length: %d\n",
cat_to_mic_len, ampe_ie_len);
sae_hexdump(AMPE_DEBUG_KEYS, "SIV- Got AAD[3]: ", (unsigned char *) &mgmt->action,
cat_to_mic_len);
if (r != 1) {
sae_debug(AMPE_DEBUG_KEYS, "Protection check failed\n");
free(clear_ampe_ie);
return -1;
}
if (ampe_ie_len != clear_ampe_ie[1] + 2) {
sae_debug(AMPE_DEBUG_KEYS, "AMPE -Invalid length (expected %d, got %d)\n",
ampe_ie_len, clear_ampe_ie[1] + 2);
free(clear_ampe_ie);
return -1;
}
sae_hexdump(AMPE_DEBUG_KEYS, "AMPE IE: ", clear_ampe_ie, ampe_ie_len);
parse_ies(clear_ampe_ie, ampe_ie_len, &ies_parsed);
if (memcmp(ies_parsed.ampe->peer_nonce, null_nonce, 32) != 0 &&
memcmp(ies_parsed.ampe->peer_nonce, cand->my_nonce, 32) != 0) {
sae_hexdump(AMPE_DEBUG_KEYS, "IE peer_nonce ", ies_parsed.ampe->peer_nonce, 32);
sae_debug(AMPE_DEBUG_KEYS, "Unexpected nonce\n");
free(clear_ampe_ie);
return -1;
}
memcpy(cand->peer_nonce, ies_parsed.ampe->local_nonce, 32);
gtkdata = ies_parsed.ampe->variable;
memcpy(cand->mgtk, gtkdata, sizeof(cand->mgtk));
sae_hexdump(AMPE_DEBUG_KEYS, "Received mgtk: ", cand->mgtk, sizeof(cand->mgtk));
key_expiration_p = (unsigned int *) (gtkdata + 16 + 8);
cand->mgtk_expiration = le32toh(*key_expiration_p);
igtkdata = gtkdata + 16 + 8 + 4;
if (mesh->conf->pmf) {
cand->igtk_keyid = le16toh(*(u16 *) igtkdata);
igtkdata += 2 + 6;
memcpy(cand->igtk, igtkdata, 16);
}
free(clear_ampe_ie);
return -1;
#undef MIC_IE_BODY_SIZE
}
