/*
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* GCM with GMAC Protocol (GCMP)
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* Copyright (c) 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 "rtw_crypto_wrap.h"
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#include "aes.h"
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#include "aes_wrap.h"
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#include "wlancrypto_wrap.h"
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static void gcmp_aad_nonce(_adapter * padapter, 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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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 & WLAN_FC_STYPE_QOS_DATA) {
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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 + 24;
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if (addr4)
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qc += ETH_ALEN;
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}
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}
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fc &= ~(WLAN_FC_RETRY | WLAN_FC_PWRMGT | WLAN_FC_MOREDATA);
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WPA_PUT_LE16(aad, fc);
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pos = aad + 2;
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os_memcpy(pos, GetAddr1Ptr((u8 *)hdr), 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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wpa_printf(_MSG_INFO_, "pos - aad = %u, qos(%d)\n", (pos - aad), qos);
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os_memcpy(pos, (u8 *)hdr + 24, 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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/* only spp mode need to refer QoS bit7 */
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if (padapter->registrypriv.amsdu_mode != RTW_AMSDU_MODE_SPP)
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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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wpa_printf(_MSG_INFO_, "pos - aad = %u\n", (pos - aad));
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*aad_len = pos - aad;
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os_memcpy(nonce, hdr->addr2, ETH_ALEN);
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nonce[6] = data[7]; /* PN5 */
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nonce[7] = data[6]; /* PN4 */
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nonce[8] = data[5]; /* PN3 */
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nonce[9] = data[4]; /* PN2 */
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nonce[10] = data[1]; /* PN1 */
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nonce[11] = data[0]; /* PN0 */
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}
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/**
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* gcmp_decrypt -
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* @tk: the temporal key
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* @tk_len: length of @tk
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* @hdr: the mac header
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* @data: payload after mac header (PN + enc_data + MIC)
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* @data_len: length of @data (PN + enc_data + MIC)
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* @decrypted_len: length of the data decrypted
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*/
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u8 * gcmp_decrypt(_adapter *padapter, const u8 *tk, size_t tk_len, 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[12], *plain;
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size_t aad_len, mlen;
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const u8 *m;
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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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m = data + 8;
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mlen = data_len - 8 - 16;
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os_memset(aad, 0, sizeof(aad));
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gcmp_aad_nonce(padapter, hdr, data, aad, &aad_len, nonce);
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wpa_hexdump(_MSG_EXCESSIVE_, "GCMP AAD", aad, aad_len);
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wpa_hexdump(_MSG_EXCESSIVE_, "GCMP nonce", nonce, sizeof(nonce));
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if (aes_gcm_ad(tk, tk_len, nonce, sizeof(nonce), m, mlen, aad, aad_len,
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m + 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 GCMP 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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rtw_mfree(plain, data_len + AES_BLOCK_SIZE);
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return NULL;
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}
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*decrypted_len = mlen;
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return plain;
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}
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/**
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* gcmp_encrypt -
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* @tk: the temporal key
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* @tk_len: length of @tk
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* @frame: the point to mac header, the frame including mac header and payload,
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* if @pn is NULL, then the frame including pn
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* @len: length of @frame
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* length = mac header + payload
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* @hdrlen: length of the mac header
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* @qos: pointer to the QOS field of the frame
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* @pn: packet number
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* @keyid: key id
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* @encrypted_len: length of the encrypted frame
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* including mac header, pn, payload and MIC
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*/
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u8 * gcmp_encrypt(_adapter *padapter, const u8 *tk, size_t tk_len, const u8 *frame, size_t len,
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size_t hdrlen, const u8 *qos,
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const u8 *pn, int keyid, size_t *encrypted_len)
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{
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u8 aad[30], nonce[12], *crypt, *pos;
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const u8 *pdata;
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size_t aad_len, plen;
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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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if (pn == NULL) {
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os_memcpy(crypt, frame, hdrlen + 8);
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hdr = (struct ieee80211_hdr *)crypt;
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pos = crypt + hdrlen + 8;
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pdata = frame + hdrlen + 8;
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} else {
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os_memcpy(crypt, frame, hdrlen);
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hdr = (struct ieee80211_hdr *)crypt;
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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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pdata = frame + hdrlen;
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}
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os_memset(aad, 0, sizeof(aad));
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gcmp_aad_nonce(padapter, hdr, crypt + hdrlen, aad, &aad_len, nonce);
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wpa_hexdump(_MSG_EXCESSIVE_, "GCMP AAD", aad, aad_len);
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wpa_hexdump(_MSG_EXCESSIVE_, "GCMP nonce", nonce, sizeof(nonce));
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if (aes_gcm_ae(tk, tk_len, nonce, sizeof(nonce), pdata, plen,
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aad, aad_len, pos, pos + plen) < 0) {
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rtw_mfree(crypt, hdrlen + 8 + plen + 16 + AES_BLOCK_SIZE);
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return NULL;
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}
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wpa_hexdump(_MSG_EXCESSIVE_, "GCMP MIC", pos + plen, 16);
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wpa_hexdump(_MSG_EXCESSIVE_, "GCMP encrypted", pos, 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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