cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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lib80211_crypt_ccmp.c (10910B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * lib80211 crypt: host-based CCMP encryption implementation for lib80211
      4 *
      5 * Copyright (c) 2003-2004, Jouni Malinen <j@w1.fi>
      6 * Copyright (c) 2008, John W. Linville <linville@tuxdriver.com>
      7 */
      8
      9#include <linux/kernel.h>
     10#include <linux/err.h>
     11#include <linux/module.h>
     12#include <linux/init.h>
     13#include <linux/slab.h>
     14#include <linux/random.h>
     15#include <linux/skbuff.h>
     16#include <linux/netdevice.h>
     17#include <linux/if_ether.h>
     18#include <linux/if_arp.h>
     19#include <asm/string.h>
     20#include <linux/wireless.h>
     21
     22#include <linux/ieee80211.h>
     23
     24#include <linux/crypto.h>
     25#include <crypto/aead.h>
     26
     27#include <net/lib80211.h>
     28
     29MODULE_AUTHOR("Jouni Malinen");
     30MODULE_DESCRIPTION("Host AP crypt: CCMP");
     31MODULE_LICENSE("GPL");
     32
     33#define AES_BLOCK_LEN 16
     34#define CCMP_HDR_LEN 8
     35#define CCMP_MIC_LEN 8
     36#define CCMP_TK_LEN 16
     37#define CCMP_PN_LEN 6
     38
     39struct lib80211_ccmp_data {
     40	u8 key[CCMP_TK_LEN];
     41	int key_set;
     42
     43	u8 tx_pn[CCMP_PN_LEN];
     44	u8 rx_pn[CCMP_PN_LEN];
     45
     46	u32 dot11RSNAStatsCCMPFormatErrors;
     47	u32 dot11RSNAStatsCCMPReplays;
     48	u32 dot11RSNAStatsCCMPDecryptErrors;
     49
     50	int key_idx;
     51
     52	struct crypto_aead *tfm;
     53
     54	/* scratch buffers for virt_to_page() (crypto API) */
     55	u8 tx_aad[2 * AES_BLOCK_LEN];
     56	u8 rx_aad[2 * AES_BLOCK_LEN];
     57};
     58
     59static void *lib80211_ccmp_init(int key_idx)
     60{
     61	struct lib80211_ccmp_data *priv;
     62
     63	priv = kzalloc(sizeof(*priv), GFP_ATOMIC);
     64	if (priv == NULL)
     65		goto fail;
     66	priv->key_idx = key_idx;
     67
     68	priv->tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);
     69	if (IS_ERR(priv->tfm)) {
     70		priv->tfm = NULL;
     71		goto fail;
     72	}
     73
     74	return priv;
     75
     76      fail:
     77	if (priv) {
     78		if (priv->tfm)
     79			crypto_free_aead(priv->tfm);
     80		kfree(priv);
     81	}
     82
     83	return NULL;
     84}
     85
     86static void lib80211_ccmp_deinit(void *priv)
     87{
     88	struct lib80211_ccmp_data *_priv = priv;
     89	if (_priv && _priv->tfm)
     90		crypto_free_aead(_priv->tfm);
     91	kfree(priv);
     92}
     93
     94static int ccmp_init_iv_and_aad(const struct ieee80211_hdr *hdr,
     95				const u8 *pn, u8 *iv, u8 *aad)
     96{
     97	u8 *pos, qc = 0;
     98	size_t aad_len;
     99	int a4_included, qc_included;
    100
    101	a4_included = ieee80211_has_a4(hdr->frame_control);
    102	qc_included = ieee80211_is_data_qos(hdr->frame_control);
    103
    104	aad_len = 22;
    105	if (a4_included)
    106		aad_len += 6;
    107	if (qc_included) {
    108		pos = (u8 *) & hdr->addr4;
    109		if (a4_included)
    110			pos += 6;
    111		qc = *pos & 0x0f;
    112		aad_len += 2;
    113	}
    114
    115	/* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC
    116	 * mode authentication are not allowed to collide, yet both are derived
    117	 * from the same vector. We only set L := 1 here to indicate that the
    118	 * data size can be represented in (L+1) bytes. The CCM layer will take
    119	 * care of storing the data length in the top (L+1) bytes and setting
    120	 * and clearing the other bits as is required to derive the two IVs.
    121	 */
    122	iv[0] = 0x1;
    123
    124	/* Nonce: QC | A2 | PN */
    125	iv[1] = qc;
    126	memcpy(iv + 2, hdr->addr2, ETH_ALEN);
    127	memcpy(iv + 8, pn, CCMP_PN_LEN);
    128
    129	/* AAD:
    130	 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
    131	 * A1 | A2 | A3
    132	 * SC with bits 4..15 (seq#) masked to zero
    133	 * A4 (if present)
    134	 * QC (if present)
    135	 */
    136	pos = (u8 *) hdr;
    137	aad[0] = pos[0] & 0x8f;
    138	aad[1] = pos[1] & 0xc7;
    139	memcpy(aad + 2, hdr->addr1, 3 * ETH_ALEN);
    140	pos = (u8 *) & hdr->seq_ctrl;
    141	aad[20] = pos[0] & 0x0f;
    142	aad[21] = 0;		/* all bits masked */
    143	memset(aad + 22, 0, 8);
    144	if (a4_included)
    145		memcpy(aad + 22, hdr->addr4, ETH_ALEN);
    146	if (qc_included) {
    147		aad[a4_included ? 28 : 22] = qc;
    148		/* rest of QC masked */
    149	}
    150	return aad_len;
    151}
    152
    153static int lib80211_ccmp_hdr(struct sk_buff *skb, int hdr_len,
    154			      u8 *aeskey, int keylen, void *priv)
    155{
    156	struct lib80211_ccmp_data *key = priv;
    157	int i;
    158	u8 *pos;
    159
    160	if (skb_headroom(skb) < CCMP_HDR_LEN || skb->len < hdr_len)
    161		return -1;
    162
    163	if (aeskey != NULL && keylen >= CCMP_TK_LEN)
    164		memcpy(aeskey, key->key, CCMP_TK_LEN);
    165
    166	pos = skb_push(skb, CCMP_HDR_LEN);
    167	memmove(pos, pos + CCMP_HDR_LEN, hdr_len);
    168	pos += hdr_len;
    169
    170	i = CCMP_PN_LEN - 1;
    171	while (i >= 0) {
    172		key->tx_pn[i]++;
    173		if (key->tx_pn[i] != 0)
    174			break;
    175		i--;
    176	}
    177
    178	*pos++ = key->tx_pn[5];
    179	*pos++ = key->tx_pn[4];
    180	*pos++ = 0;
    181	*pos++ = (key->key_idx << 6) | (1 << 5) /* Ext IV included */ ;
    182	*pos++ = key->tx_pn[3];
    183	*pos++ = key->tx_pn[2];
    184	*pos++ = key->tx_pn[1];
    185	*pos++ = key->tx_pn[0];
    186
    187	return CCMP_HDR_LEN;
    188}
    189
    190static int lib80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
    191{
    192	struct lib80211_ccmp_data *key = priv;
    193	struct ieee80211_hdr *hdr;
    194	struct aead_request *req;
    195	struct scatterlist sg[2];
    196	u8 *aad = key->tx_aad;
    197	u8 iv[AES_BLOCK_LEN];
    198	int len, data_len, aad_len;
    199	int ret;
    200
    201	if (skb_tailroom(skb) < CCMP_MIC_LEN || skb->len < hdr_len)
    202		return -1;
    203
    204	data_len = skb->len - hdr_len;
    205	len = lib80211_ccmp_hdr(skb, hdr_len, NULL, 0, priv);
    206	if (len < 0)
    207		return -1;
    208
    209	req = aead_request_alloc(key->tfm, GFP_ATOMIC);
    210	if (!req)
    211		return -ENOMEM;
    212
    213	hdr = (struct ieee80211_hdr *)skb->data;
    214	aad_len = ccmp_init_iv_and_aad(hdr, key->tx_pn, iv, aad);
    215
    216	skb_put(skb, CCMP_MIC_LEN);
    217
    218	sg_init_table(sg, 2);
    219	sg_set_buf(&sg[0], aad, aad_len);
    220	sg_set_buf(&sg[1], skb->data + hdr_len + CCMP_HDR_LEN,
    221		   data_len + CCMP_MIC_LEN);
    222
    223	aead_request_set_callback(req, 0, NULL, NULL);
    224	aead_request_set_ad(req, aad_len);
    225	aead_request_set_crypt(req, sg, sg, data_len, iv);
    226
    227	ret = crypto_aead_encrypt(req);
    228	aead_request_free(req);
    229
    230	return ret;
    231}
    232
    233/*
    234 * deal with seq counter wrapping correctly.
    235 * refer to timer_after() for jiffies wrapping handling
    236 */
    237static inline int ccmp_replay_check(u8 *pn_n, u8 *pn_o)
    238{
    239	u32 iv32_n, iv16_n;
    240	u32 iv32_o, iv16_o;
    241
    242	iv32_n = (pn_n[0] << 24) | (pn_n[1] << 16) | (pn_n[2] << 8) | pn_n[3];
    243	iv16_n = (pn_n[4] << 8) | pn_n[5];
    244
    245	iv32_o = (pn_o[0] << 24) | (pn_o[1] << 16) | (pn_o[2] << 8) | pn_o[3];
    246	iv16_o = (pn_o[4] << 8) | pn_o[5];
    247
    248	if ((s32)iv32_n - (s32)iv32_o < 0 ||
    249	    (iv32_n == iv32_o && iv16_n <= iv16_o))
    250		return 1;
    251	return 0;
    252}
    253
    254static int lib80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv)
    255{
    256	struct lib80211_ccmp_data *key = priv;
    257	u8 keyidx, *pos;
    258	struct ieee80211_hdr *hdr;
    259	struct aead_request *req;
    260	struct scatterlist sg[2];
    261	u8 *aad = key->rx_aad;
    262	u8 iv[AES_BLOCK_LEN];
    263	u8 pn[6];
    264	int aad_len, ret;
    265	size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN;
    266
    267	if (skb->len < hdr_len + CCMP_HDR_LEN + CCMP_MIC_LEN) {
    268		key->dot11RSNAStatsCCMPFormatErrors++;
    269		return -1;
    270	}
    271
    272	hdr = (struct ieee80211_hdr *)skb->data;
    273	pos = skb->data + hdr_len;
    274	keyidx = pos[3];
    275	if (!(keyidx & (1 << 5))) {
    276		net_dbg_ratelimited("CCMP: received packet without ExtIV flag from %pM\n",
    277				    hdr->addr2);
    278		key->dot11RSNAStatsCCMPFormatErrors++;
    279		return -2;
    280	}
    281	keyidx >>= 6;
    282	if (key->key_idx != keyidx) {
    283		net_dbg_ratelimited("CCMP: RX tkey->key_idx=%d frame keyidx=%d\n",
    284				    key->key_idx, keyidx);
    285		return -6;
    286	}
    287	if (!key->key_set) {
    288		net_dbg_ratelimited("CCMP: received packet from %pM with keyid=%d that does not have a configured key\n",
    289				    hdr->addr2, keyidx);
    290		return -3;
    291	}
    292
    293	pn[0] = pos[7];
    294	pn[1] = pos[6];
    295	pn[2] = pos[5];
    296	pn[3] = pos[4];
    297	pn[4] = pos[1];
    298	pn[5] = pos[0];
    299	pos += 8;
    300
    301	if (ccmp_replay_check(pn, key->rx_pn)) {
    302#ifdef CONFIG_LIB80211_DEBUG
    303		net_dbg_ratelimited("CCMP: replay detected: STA=%pM previous PN %02x%02x%02x%02x%02x%02x received PN %02x%02x%02x%02x%02x%02x\n",
    304				    hdr->addr2,
    305				    key->rx_pn[0], key->rx_pn[1], key->rx_pn[2],
    306				    key->rx_pn[3], key->rx_pn[4], key->rx_pn[5],
    307				    pn[0], pn[1], pn[2], pn[3], pn[4], pn[5]);
    308#endif
    309		key->dot11RSNAStatsCCMPReplays++;
    310		return -4;
    311	}
    312
    313	req = aead_request_alloc(key->tfm, GFP_ATOMIC);
    314	if (!req)
    315		return -ENOMEM;
    316
    317	aad_len = ccmp_init_iv_and_aad(hdr, pn, iv, aad);
    318
    319	sg_init_table(sg, 2);
    320	sg_set_buf(&sg[0], aad, aad_len);
    321	sg_set_buf(&sg[1], pos, data_len);
    322
    323	aead_request_set_callback(req, 0, NULL, NULL);
    324	aead_request_set_ad(req, aad_len);
    325	aead_request_set_crypt(req, sg, sg, data_len, iv);
    326
    327	ret = crypto_aead_decrypt(req);
    328	aead_request_free(req);
    329
    330	if (ret) {
    331		net_dbg_ratelimited("CCMP: decrypt failed: STA=%pM (%d)\n",
    332				    hdr->addr2, ret);
    333		key->dot11RSNAStatsCCMPDecryptErrors++;
    334		return -5;
    335	}
    336
    337	memcpy(key->rx_pn, pn, CCMP_PN_LEN);
    338
    339	/* Remove hdr and MIC */
    340	memmove(skb->data + CCMP_HDR_LEN, skb->data, hdr_len);
    341	skb_pull(skb, CCMP_HDR_LEN);
    342	skb_trim(skb, skb->len - CCMP_MIC_LEN);
    343
    344	return keyidx;
    345}
    346
    347static int lib80211_ccmp_set_key(void *key, int len, u8 * seq, void *priv)
    348{
    349	struct lib80211_ccmp_data *data = priv;
    350	int keyidx;
    351	struct crypto_aead *tfm = data->tfm;
    352
    353	keyidx = data->key_idx;
    354	memset(data, 0, sizeof(*data));
    355	data->key_idx = keyidx;
    356	data->tfm = tfm;
    357	if (len == CCMP_TK_LEN) {
    358		memcpy(data->key, key, CCMP_TK_LEN);
    359		data->key_set = 1;
    360		if (seq) {
    361			data->rx_pn[0] = seq[5];
    362			data->rx_pn[1] = seq[4];
    363			data->rx_pn[2] = seq[3];
    364			data->rx_pn[3] = seq[2];
    365			data->rx_pn[4] = seq[1];
    366			data->rx_pn[5] = seq[0];
    367		}
    368		if (crypto_aead_setauthsize(data->tfm, CCMP_MIC_LEN) ||
    369		    crypto_aead_setkey(data->tfm, data->key, CCMP_TK_LEN))
    370			return -1;
    371	} else if (len == 0)
    372		data->key_set = 0;
    373	else
    374		return -1;
    375
    376	return 0;
    377}
    378
    379static int lib80211_ccmp_get_key(void *key, int len, u8 * seq, void *priv)
    380{
    381	struct lib80211_ccmp_data *data = priv;
    382
    383	if (len < CCMP_TK_LEN)
    384		return -1;
    385
    386	if (!data->key_set)
    387		return 0;
    388	memcpy(key, data->key, CCMP_TK_LEN);
    389
    390	if (seq) {
    391		seq[0] = data->tx_pn[5];
    392		seq[1] = data->tx_pn[4];
    393		seq[2] = data->tx_pn[3];
    394		seq[3] = data->tx_pn[2];
    395		seq[4] = data->tx_pn[1];
    396		seq[5] = data->tx_pn[0];
    397	}
    398
    399	return CCMP_TK_LEN;
    400}
    401
    402static void lib80211_ccmp_print_stats(struct seq_file *m, void *priv)
    403{
    404	struct lib80211_ccmp_data *ccmp = priv;
    405
    406	seq_printf(m,
    407		   "key[%d] alg=CCMP key_set=%d "
    408		   "tx_pn=%02x%02x%02x%02x%02x%02x "
    409		   "rx_pn=%02x%02x%02x%02x%02x%02x "
    410		   "format_errors=%d replays=%d decrypt_errors=%d\n",
    411		   ccmp->key_idx, ccmp->key_set,
    412		   ccmp->tx_pn[0], ccmp->tx_pn[1], ccmp->tx_pn[2],
    413		   ccmp->tx_pn[3], ccmp->tx_pn[4], ccmp->tx_pn[5],
    414		   ccmp->rx_pn[0], ccmp->rx_pn[1], ccmp->rx_pn[2],
    415		   ccmp->rx_pn[3], ccmp->rx_pn[4], ccmp->rx_pn[5],
    416		   ccmp->dot11RSNAStatsCCMPFormatErrors,
    417		   ccmp->dot11RSNAStatsCCMPReplays,
    418		   ccmp->dot11RSNAStatsCCMPDecryptErrors);
    419}
    420
    421static struct lib80211_crypto_ops lib80211_crypt_ccmp = {
    422	.name = "CCMP",
    423	.init = lib80211_ccmp_init,
    424	.deinit = lib80211_ccmp_deinit,
    425	.encrypt_mpdu = lib80211_ccmp_encrypt,
    426	.decrypt_mpdu = lib80211_ccmp_decrypt,
    427	.encrypt_msdu = NULL,
    428	.decrypt_msdu = NULL,
    429	.set_key = lib80211_ccmp_set_key,
    430	.get_key = lib80211_ccmp_get_key,
    431	.print_stats = lib80211_ccmp_print_stats,
    432	.extra_mpdu_prefix_len = CCMP_HDR_LEN,
    433	.extra_mpdu_postfix_len = CCMP_MIC_LEN,
    434	.owner = THIS_MODULE,
    435};
    436
    437static int __init lib80211_crypto_ccmp_init(void)
    438{
    439	return lib80211_register_crypto_ops(&lib80211_crypt_ccmp);
    440}
    441
    442static void __exit lib80211_crypto_ccmp_exit(void)
    443{
    444	lib80211_unregister_crypto_ops(&lib80211_crypt_ccmp);
    445}
    446
    447module_init(lib80211_crypto_ccmp_init);
    448module_exit(lib80211_crypto_ccmp_exit);