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hostap/wlantest/ccmp.c
Jouni Malinen f2f66ad7e8 wlantest: Fix CCMP-256 cipher 
TK was incorrectly truncated in a way that resulted in CCMP (128-bit
key) encryption being used in practice.

Signed-hostap: Jouni Malinen <jouni@qca.qualcomm.com>
2013-04-05 22:18:25 +03:00

267 lines
6.6 KiB
C
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/*
* CTR with CBC-MAC Protocol (CCMP)
* Copyright (c) 2010-2012, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "utils/includes.h"
#include "utils/common.h"
#include "common/ieee802_11_defs.h"
#include "crypto/aes.h"
#include "crypto/aes_wrap.h"
#include "wlantest.h"
static void ccmp_aad_nonce(const struct ieee80211_hdr *hdr, const u8 *data,
u8 *aad, size_t *aad_len, u8 *nonce)
{
u16 fc, stype, seq;
int qos = 0, addr4 = 0;
u8 *pos;
nonce[0] = 0;
fc = le_to_host16(hdr->frame_control);
stype = WLAN_FC_GET_STYPE(fc);
if ((fc & (WLAN_FC_TODS | WLAN_FC_FROMDS)) ==
(WLAN_FC_TODS | WLAN_FC_FROMDS))
addr4 = 1;
if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_DATA) {
fc &= ~0x0070; /* Mask subtype bits */
if (stype & 0x08) {
const u8 *qc;
qos = 1;
fc &= ~WLAN_FC_ORDER;
qc = (const u8 *) (hdr + 1);
if (addr4)
qc += ETH_ALEN;
nonce[0] = qc[0] & 0x0f;
}
} else if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_MGMT)
nonce[0] |= 0x10; /* Management */
fc &= ~(WLAN_FC_RETRY | WLAN_FC_PWRMGT | WLAN_FC_MOREDATA);
fc |= WLAN_FC_ISWEP;
WPA_PUT_LE16(aad, fc);
pos = aad + 2;
os_memcpy(pos, hdr->addr1, 3 * ETH_ALEN);
pos += 3 * ETH_ALEN;
seq = le_to_host16(hdr->seq_ctrl);
seq &= ~0xfff0; /* Mask Seq#; do not modify Frag# */
WPA_PUT_LE16(pos, seq);
pos += 2;
os_memcpy(pos, hdr + 1, addr4 * ETH_ALEN + qos * 2);
pos += addr4 * ETH_ALEN;
if (qos) {
pos[0] &= ~0x70;
if (1 /* FIX: either device has SPP A-MSDU Capab = 0 */)
pos[0] &= ~0x80;
pos++;
*pos++ = 0x00;
}
*aad_len = pos - aad;
os_memcpy(nonce + 1, hdr->addr2, ETH_ALEN);
nonce[7] = data[7]; /* PN5 */
nonce[8] = data[6]; /* PN4 */
nonce[9] = data[5]; /* PN3 */
nonce[10] = data[4]; /* PN2 */
nonce[11] = data[1]; /* PN1 */
nonce[12] = data[0]; /* PN0 */
}
u8 * ccmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
const u8 *data, size_t data_len, size_t *decrypted_len)
{
u8 aad[30], nonce[13];
size_t aad_len;
size_t mlen;
u8 *plain;
if (data_len < 8 + 8)
return NULL;
plain = os_malloc(data_len + AES_BLOCK_SIZE);
if (plain == NULL)
return NULL;
mlen = data_len - 8 - 8;
os_memset(aad, 0, sizeof(aad));
ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
if (aes_ccm_ad(tk, 16, nonce, 8, data + 8, mlen, aad, aad_len,
data + 8 + mlen, plain) < 0) {
u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
wpa_printf(MSG_INFO, "Invalid CCMP MIC in frame: A1=" MACSTR
" A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
MAC2STR(hdr->addr3),
WLAN_GET_SEQ_SEQ(seq_ctrl),
WLAN_GET_SEQ_FRAG(seq_ctrl));
os_free(plain);
return NULL;
}
wpa_hexdump(MSG_EXCESSIVE, "CCMP decrypted", plain, mlen);
*decrypted_len = mlen;
return plain;
}
void ccmp_get_pn(u8 *pn, const u8 *data)
{
pn[0] = data[7]; /* PN5 */
pn[1] = data[6]; /* PN4 */
pn[2] = data[5]; /* PN3 */
pn[3] = data[4]; /* PN2 */
pn[4] = data[1]; /* PN1 */
pn[5] = data[0]; /* PN0 */
}
u8 * ccmp_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
u8 *pn, int keyid, size_t *encrypted_len)
{
u8 aad[30], nonce[13];
size_t aad_len, plen;
u8 *crypt, *pos;
struct ieee80211_hdr *hdr;
if (len < hdrlen || hdrlen < 24)
return NULL;
plen = len - hdrlen;
crypt = os_malloc(hdrlen + 8 + plen + 8 + AES_BLOCK_SIZE);
if (crypt == NULL)
return NULL;
os_memcpy(crypt, frame, hdrlen);
hdr = (struct ieee80211_hdr *) crypt;
hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
pos = crypt + hdrlen;
*pos++ = pn[5]; /* PN0 */
*pos++ = pn[4]; /* PN1 */
*pos++ = 0x00; /* Rsvd */
*pos++ = 0x20 | (keyid << 6);
*pos++ = pn[3]; /* PN2 */
*pos++ = pn[2]; /* PN3 */
*pos++ = pn[1]; /* PN4 */
*pos++ = pn[0]; /* PN5 */
os_memset(aad, 0, sizeof(aad));
ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
if (aes_ccm_ae(tk, 16, nonce, 8, frame + hdrlen, plen, aad, aad_len,
pos, pos + plen) < 0) {
os_free(crypt);
return NULL;
}
wpa_hexdump(MSG_EXCESSIVE, "CCMP encrypted", crypt + hdrlen + 8, plen);
*encrypted_len = hdrlen + 8 + plen + 8;
return crypt;
}
u8 * ccmp_256_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
const u8 *data, size_t data_len, size_t *decrypted_len)
{
u8 aad[30], nonce[13];
size_t aad_len;
size_t mlen;
u8 *plain;
if (data_len < 8 + 16)
return NULL;
plain = os_malloc(data_len + AES_BLOCK_SIZE);
if (plain == NULL)
return NULL;
mlen = data_len - 8 - 16;
os_memset(aad, 0, sizeof(aad));
ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 AAD", aad, aad_len);
wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 nonce", nonce, 13);
if (aes_ccm_ad(tk, 32, nonce, 16, data + 8, mlen, aad, aad_len,
data + 8 + mlen, plain) < 0) {
u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
wpa_printf(MSG_INFO, "Invalid CCMP-256 MIC in frame: A1=" MACSTR
" A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
MAC2STR(hdr->addr3),
WLAN_GET_SEQ_SEQ(seq_ctrl),
WLAN_GET_SEQ_FRAG(seq_ctrl));
os_free(plain);
return NULL;
}
wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 decrypted", plain, mlen);
*decrypted_len = mlen;
return plain;
}
u8 * ccmp_256_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen,
u8 *qos, u8 *pn, int keyid, size_t *encrypted_len)
{
u8 aad[30], nonce[13];
size_t aad_len, plen;
u8 *crypt, *pos;
struct ieee80211_hdr *hdr;
if (len < hdrlen || hdrlen < 24)
return NULL;
plen = len - hdrlen;
crypt = os_malloc(hdrlen + 8 + plen + 16 + AES_BLOCK_SIZE);
if (crypt == NULL)
return NULL;
os_memcpy(crypt, frame, hdrlen);
hdr = (struct ieee80211_hdr *) crypt;
hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
pos = crypt + hdrlen;
*pos++ = pn[5]; /* PN0 */
*pos++ = pn[4]; /* PN1 */
*pos++ = 0x00; /* Rsvd */
*pos++ = 0x20 | (keyid << 6);
*pos++ = pn[3]; /* PN2 */
*pos++ = pn[2]; /* PN3 */
*pos++ = pn[1]; /* PN4 */
*pos++ = pn[0]; /* PN5 */
os_memset(aad, 0, sizeof(aad));
ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 AAD", aad, aad_len);
wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 nonce", nonce, 13);
if (aes_ccm_ae(tk, 32, nonce, 16, frame + hdrlen, plen, aad, aad_len,
pos, pos + plen) < 0) {
os_free(crypt);
return NULL;
}
wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 encrypted", crypt + hdrlen + 8,
plen);
*encrypted_len = hdrlen + 8 + plen + 16;
return crypt;
}
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