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SAE: Check hmac_sha256() result in sae_token_hash()

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In theory, hmac_sha256() might fail, so check for that possibility
instead of continuing with undetermined index value that could point to
an arbitrary token entry.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2020-03-08 16:51:30 +02:00
parent b0927e5d06
commit 7f1f69e897
1 changed files with 11 additions and 7 deletions
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18
src/ap/ieee802_11.c
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@ -639,13 +639,15 @@ static int use_sae_anti_clogging(struct hostapd_data *hapd)
} }
static u8 sae_token_hash(struct hostapd_data *hapd, const u8 *addr) static int sae_token_hash(struct hostapd_data *hapd, const u8 *addr, u8 *idx)
{ {
u8 hash[SHA256_MAC_LEN]; u8 hash[SHA256_MAC_LEN];
hmac_sha256(hapd->sae_token_key, sizeof(hapd->sae_token_key), if (hmac_sha256(hapd->sae_token_key, sizeof(hapd->sae_token_key),
addr, ETH_ALEN, hash); addr, ETH_ALEN, hash) < 0)
return hash[0]; return -1;
*idx = hash[0];
return 0;
} }
@ -658,9 +660,8 @@ static int check_sae_token(struct hostapd_data *hapd, const u8 *addr,
u16 token_idx; u16 token_idx;
u8 idx; u8 idx;
if (token_len != SHA256_MAC_LEN) if (token_len != SHA256_MAC_LEN || sae_token_hash(hapd, addr, &idx) < 0)
return -1; return -1;
idx = sae_token_hash(hapd, addr);
token_idx = hapd->sae_pending_token_idx[idx]; token_idx = hapd->sae_pending_token_idx[idx];
if (token_idx == 0 || token_idx != WPA_GET_BE16(token)) { if (token_idx == 0 || token_idx != WPA_GET_BE16(token)) {
wpa_printf(MSG_DEBUG, "SAE: Invalid anti-clogging token from " wpa_printf(MSG_DEBUG, "SAE: Invalid anti-clogging token from "
@ -724,7 +725,10 @@ static struct wpabuf * auth_build_token_req(struct hostapd_data *hapd,
wpabuf_put_u8(buf, WLAN_EID_EXT_ANTI_CLOGGING_TOKEN); wpabuf_put_u8(buf, WLAN_EID_EXT_ANTI_CLOGGING_TOKEN);
} }
p_idx = sae_token_hash(hapd, addr); if (sae_token_hash(hapd, addr, &p_idx) < 0) {
wpabuf_free(buf);
return NULL;
}
token_idx = hapd->sae_pending_token_idx[p_idx]; token_idx = hapd->sae_pending_token_idx[p_idx];
if (!token_idx) { if (!token_idx) {
hapd->sae_token_idx++; hapd->sae_token_idx++;