mirror of
https://github.com/vanhoefm/fragattacks.git
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f2f66ad7e8
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>
268 lines
6.6 KiB
C
268 lines
6.6 KiB
C
/*
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* CTR with CBC-MAC Protocol (CCMP)
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* Copyright (c) 2010-2012, Jouni Malinen <j@w1.fi>
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*
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* This software may be distributed under the terms of the BSD license.
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* See README for more details.
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*/
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#include "utils/includes.h"
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#include "utils/common.h"
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#include "common/ieee802_11_defs.h"
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#include "crypto/aes.h"
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#include "crypto/aes_wrap.h"
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#include "wlantest.h"
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static void ccmp_aad_nonce(const struct ieee80211_hdr *hdr, const u8 *data,
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u8 *aad, size_t *aad_len, u8 *nonce)
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{
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u16 fc, stype, seq;
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int qos = 0, addr4 = 0;
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u8 *pos;
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nonce[0] = 0;
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fc = le_to_host16(hdr->frame_control);
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stype = WLAN_FC_GET_STYPE(fc);
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if ((fc & (WLAN_FC_TODS | WLAN_FC_FROMDS)) ==
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(WLAN_FC_TODS | WLAN_FC_FROMDS))
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addr4 = 1;
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if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_DATA) {
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fc &= ~0x0070; /* Mask subtype bits */
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if (stype & 0x08) {
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const u8 *qc;
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qos = 1;
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fc &= ~WLAN_FC_ORDER;
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qc = (const u8 *) (hdr + 1);
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if (addr4)
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qc += ETH_ALEN;
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nonce[0] = qc[0] & 0x0f;
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}
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} else if (WLAN_FC_GET_TYPE(fc) == WLAN_FC_TYPE_MGMT)
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nonce[0] |= 0x10; /* Management */
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fc &= ~(WLAN_FC_RETRY | WLAN_FC_PWRMGT | WLAN_FC_MOREDATA);
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fc |= WLAN_FC_ISWEP;
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WPA_PUT_LE16(aad, fc);
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pos = aad + 2;
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os_memcpy(pos, hdr->addr1, 3 * ETH_ALEN);
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pos += 3 * ETH_ALEN;
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seq = le_to_host16(hdr->seq_ctrl);
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seq &= ~0xfff0; /* Mask Seq#; do not modify Frag# */
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WPA_PUT_LE16(pos, seq);
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pos += 2;
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os_memcpy(pos, hdr + 1, addr4 * ETH_ALEN + qos * 2);
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pos += addr4 * ETH_ALEN;
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if (qos) {
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pos[0] &= ~0x70;
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if (1 /* FIX: either device has SPP A-MSDU Capab = 0 */)
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pos[0] &= ~0x80;
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pos++;
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*pos++ = 0x00;
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}
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*aad_len = pos - aad;
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os_memcpy(nonce + 1, hdr->addr2, ETH_ALEN);
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nonce[7] = data[7]; /* PN5 */
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nonce[8] = data[6]; /* PN4 */
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nonce[9] = data[5]; /* PN3 */
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nonce[10] = data[4]; /* PN2 */
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nonce[11] = data[1]; /* PN1 */
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nonce[12] = data[0]; /* PN0 */
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}
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u8 * ccmp_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
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const u8 *data, size_t data_len, size_t *decrypted_len)
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{
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u8 aad[30], nonce[13];
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size_t aad_len;
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size_t mlen;
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u8 *plain;
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if (data_len < 8 + 8)
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return NULL;
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plain = os_malloc(data_len + AES_BLOCK_SIZE);
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if (plain == NULL)
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return NULL;
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mlen = data_len - 8 - 8;
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os_memset(aad, 0, sizeof(aad));
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ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
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wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
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wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
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if (aes_ccm_ad(tk, 16, nonce, 8, data + 8, mlen, aad, aad_len,
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data + 8 + mlen, plain) < 0) {
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u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
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wpa_printf(MSG_INFO, "Invalid CCMP MIC in frame: A1=" MACSTR
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" A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
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MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
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MAC2STR(hdr->addr3),
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WLAN_GET_SEQ_SEQ(seq_ctrl),
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WLAN_GET_SEQ_FRAG(seq_ctrl));
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os_free(plain);
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return NULL;
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}
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wpa_hexdump(MSG_EXCESSIVE, "CCMP decrypted", plain, mlen);
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*decrypted_len = mlen;
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return plain;
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}
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void ccmp_get_pn(u8 *pn, const u8 *data)
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{
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pn[0] = data[7]; /* PN5 */
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pn[1] = data[6]; /* PN4 */
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pn[2] = data[5]; /* PN3 */
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pn[3] = data[4]; /* PN2 */
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pn[4] = data[1]; /* PN1 */
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pn[5] = data[0]; /* PN0 */
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}
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u8 * ccmp_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen, u8 *qos,
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u8 *pn, int keyid, size_t *encrypted_len)
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{
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u8 aad[30], nonce[13];
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size_t aad_len, plen;
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u8 *crypt, *pos;
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struct ieee80211_hdr *hdr;
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if (len < hdrlen || hdrlen < 24)
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return NULL;
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plen = len - hdrlen;
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crypt = os_malloc(hdrlen + 8 + plen + 8 + AES_BLOCK_SIZE);
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if (crypt == NULL)
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return NULL;
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os_memcpy(crypt, frame, hdrlen);
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hdr = (struct ieee80211_hdr *) crypt;
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hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
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pos = crypt + hdrlen;
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*pos++ = pn[5]; /* PN0 */
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*pos++ = pn[4]; /* PN1 */
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*pos++ = 0x00; /* Rsvd */
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*pos++ = 0x20 | (keyid << 6);
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*pos++ = pn[3]; /* PN2 */
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*pos++ = pn[2]; /* PN3 */
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*pos++ = pn[1]; /* PN4 */
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*pos++ = pn[0]; /* PN5 */
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os_memset(aad, 0, sizeof(aad));
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ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
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wpa_hexdump(MSG_EXCESSIVE, "CCMP AAD", aad, aad_len);
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wpa_hexdump(MSG_EXCESSIVE, "CCMP nonce", nonce, 13);
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if (aes_ccm_ae(tk, 16, nonce, 8, frame + hdrlen, plen, aad, aad_len,
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pos, pos + plen) < 0) {
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os_free(crypt);
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return NULL;
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}
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wpa_hexdump(MSG_EXCESSIVE, "CCMP encrypted", crypt + hdrlen + 8, plen);
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*encrypted_len = hdrlen + 8 + plen + 8;
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return crypt;
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}
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u8 * ccmp_256_decrypt(const u8 *tk, const struct ieee80211_hdr *hdr,
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const u8 *data, size_t data_len, size_t *decrypted_len)
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{
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u8 aad[30], nonce[13];
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size_t aad_len;
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size_t mlen;
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u8 *plain;
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if (data_len < 8 + 16)
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return NULL;
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plain = os_malloc(data_len + AES_BLOCK_SIZE);
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if (plain == NULL)
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return NULL;
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mlen = data_len - 8 - 16;
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os_memset(aad, 0, sizeof(aad));
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ccmp_aad_nonce(hdr, data, aad, &aad_len, nonce);
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wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 AAD", aad, aad_len);
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wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 nonce", nonce, 13);
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if (aes_ccm_ad(tk, 32, nonce, 16, data + 8, mlen, aad, aad_len,
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data + 8 + mlen, plain) < 0) {
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u16 seq_ctrl = le_to_host16(hdr->seq_ctrl);
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wpa_printf(MSG_INFO, "Invalid CCMP-256 MIC in frame: A1=" MACSTR
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" A2=" MACSTR " A3=" MACSTR " seq=%u frag=%u",
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MAC2STR(hdr->addr1), MAC2STR(hdr->addr2),
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MAC2STR(hdr->addr3),
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WLAN_GET_SEQ_SEQ(seq_ctrl),
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WLAN_GET_SEQ_FRAG(seq_ctrl));
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os_free(plain);
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return NULL;
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}
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wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 decrypted", plain, mlen);
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*decrypted_len = mlen;
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return plain;
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}
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u8 * ccmp_256_encrypt(const u8 *tk, u8 *frame, size_t len, size_t hdrlen,
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u8 *qos, u8 *pn, int keyid, size_t *encrypted_len)
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{
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u8 aad[30], nonce[13];
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size_t aad_len, plen;
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u8 *crypt, *pos;
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struct ieee80211_hdr *hdr;
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if (len < hdrlen || hdrlen < 24)
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return NULL;
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plen = len - hdrlen;
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crypt = os_malloc(hdrlen + 8 + plen + 16 + AES_BLOCK_SIZE);
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if (crypt == NULL)
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return NULL;
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os_memcpy(crypt, frame, hdrlen);
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hdr = (struct ieee80211_hdr *) crypt;
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hdr->frame_control |= host_to_le16(WLAN_FC_ISWEP);
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pos = crypt + hdrlen;
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*pos++ = pn[5]; /* PN0 */
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*pos++ = pn[4]; /* PN1 */
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*pos++ = 0x00; /* Rsvd */
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*pos++ = 0x20 | (keyid << 6);
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*pos++ = pn[3]; /* PN2 */
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*pos++ = pn[2]; /* PN3 */
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*pos++ = pn[1]; /* PN4 */
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*pos++ = pn[0]; /* PN5 */
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os_memset(aad, 0, sizeof(aad));
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ccmp_aad_nonce(hdr, crypt + hdrlen, aad, &aad_len, nonce);
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wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 AAD", aad, aad_len);
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wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 nonce", nonce, 13);
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if (aes_ccm_ae(tk, 32, nonce, 16, frame + hdrlen, plen, aad, aad_len,
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pos, pos + plen) < 0) {
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os_free(crypt);
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return NULL;
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}
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wpa_hexdump(MSG_EXCESSIVE, "CCMP-256 encrypted", crypt + hdrlen + 8,
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plen);
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*encrypted_len = hdrlen + 8 + plen + 16;
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return crypt;
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}
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