Commit eb0e7bf3 authored by Christina Quast's avatar Christina Quast Committed by Greg Kroah-Hartman
Browse files

staging: rtl8192u: ieee80211: ieee80211_crypt_ccmp.c: Use crypto API ccm(aes) 



Use ccm(aes) aead transform instead of invoking the AES block cipher
block by block.

Signed-off-by: default avatarChristina Quast <contact@christina-quast.de>
Reviewed-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Link: https://lore.kernel.org/r/20190816065936.12214-2-contact@christina-quast.de


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 81e0da70

drivers/staging/rtl8192u/Kconfig

+2 −0
Original line number Diff line number Diff line
@@ -6,3 +6,5 @@ config RTL8192U 
	select WIRELESS_EXT

	select WEXT_PRIV

	select CRYPTO

	select CRYPTO_AES

	select CRYPTO_CCM

drivers/staging/rtl8192u/ieee80211/ieee80211_crypt_ccmp.c

+86 −115
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include "ieee80211.h"



#include <linux/crypto.h>

#include <crypto/aead.h>

    #include <linux/scatterlist.h>



MODULE_AUTHOR("Jouni Malinen");
@@ -44,20 +45,13 @@ struct ieee80211_ccmp_data { 


	int key_idx;



	struct crypto_tfm *tfm;

	struct crypto_aead *tfm;



	/* scratch buffers for virt_to_page() (crypto API) */

	u8 tx_b0[AES_BLOCK_LEN], tx_b[AES_BLOCK_LEN],

		tx_e[AES_BLOCK_LEN], tx_s0[AES_BLOCK_LEN];

	u8 rx_b0[AES_BLOCK_LEN], rx_b[AES_BLOCK_LEN], rx_a[AES_BLOCK_LEN];

	u8 tx_aad[2 * AES_BLOCK_LEN];

	u8 rx_aad[2 * AES_BLOCK_LEN];

};



static void ieee80211_ccmp_aes_encrypt(struct crypto_tfm *tfm,

			     const u8 pt[16], u8 ct[16])

{

	crypto_cipher_encrypt_one((void *)tfm, ct, pt);

}



static void *ieee80211_ccmp_init(int key_idx)

{

	struct ieee80211_ccmp_data *priv;
@@ -67,7 +61,7 @@ static void *ieee80211_ccmp_init(int key_idx) 
		goto fail;

	priv->key_idx = key_idx;



	priv->tfm = (void *)crypto_alloc_cipher("aes", 0, 0);

	priv->tfm = crypto_alloc_aead("ccm(aes)", 0, CRYPTO_ALG_ASYNC);

	if (IS_ERR(priv->tfm)) {

		pr_debug("ieee80211_crypt_ccmp: could not allocate crypto API aes\n");

		priv->tfm = NULL;
@@ -79,7 +73,7 @@ static void *ieee80211_ccmp_init(int key_idx) 
fail:

	if (priv) {

		if (priv->tfm)

			crypto_free_cipher((void *)priv->tfm);

			crypto_free_aead(priv->tfm);

		kfree(priv);

	}
@@ -91,28 +85,17 @@ static void ieee80211_ccmp_deinit(void *priv) 
	struct ieee80211_ccmp_data *_priv = priv;



	if (_priv && _priv->tfm)

		crypto_free_cipher((void *)_priv->tfm);

		crypto_free_aead(_priv->tfm);

	kfree(priv);

}



static inline void xor_block(u8 *b, u8 *a, size_t len)

{

	int i;



	for (i = 0; i < len; i++)

		b[i] ^= a[i];

}



static void ccmp_init_blocks(struct crypto_tfm *tfm,

			     struct rtl_80211_hdr_4addr *hdr,

			     u8 *pn, size_t dlen, u8 *b0, u8 *auth,

			     u8 *s0)

static int ccmp_init_iv_and_aad(struct rtl_80211_hdr_4addr *hdr,

			     u8 *pn, u8 *iv, u8 *aad)

{

	u8 *pos, qc = 0;

	size_t aad_len;

	u16 fc;

	int a4_included, qc_included;

	u8 aad[2 * AES_BLOCK_LEN];



	fc = le16_to_cpu(hdr->frame_ctl);

	a4_included = ((fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) ==
@@ -133,18 +116,20 @@ static void ccmp_init_blocks(struct crypto_tfm *tfm, 
		qc = *pos & 0x0f;

		aad_len += 2;

	}

	/* CCM Initial Block:

	 * Flag (Include authentication header, M=3 (8-octet MIC),

	 *       L=1 (2-octet Dlen))

	 * Nonce: 0x00 | A2 | PN

	 * Dlen



	/* In CCM, the initial vectors (IV) used for CTR mode encryption and CBC

	 * mode authentication are not allowed to collide, yet both are derived

	 * from the same vector. We only set L := 1 here to indicate that the

	 * data size can be represented in (L+1) bytes. The CCM layer will take

	 * care of storing the data length in the top (L+1) bytes and setting

	 * and clearing the other bits as is required to derive the two IVs.

	 */

	b0[0] = 0x59;

	b0[1] = qc;

	memcpy(b0 + 2, hdr->addr2, ETH_ALEN);

	memcpy(b0 + 8, pn, CCMP_PN_LEN);

	b0[14] = (dlen >> 8) & 0xff;

	b0[15] = dlen & 0xff;

	iv[0] = 0x1;



	/* Nonce: QC | A2 | PN */

	iv[1] = qc;

	memcpy(iv + 2, hdr->addr2, ETH_ALEN);

	memcpy(iv + 8, pn, CCMP_PN_LEN);



	/* AAD:

	 * FC with bits 4..6 and 11..13 masked to zero; 14 is always one
@@ -154,32 +139,21 @@ static void ccmp_init_blocks(struct crypto_tfm *tfm, 
	 * QC (if present)

	 */

	pos = (u8 *)hdr;

	aad[0] = 0; /* aad_len >> 8 */

	aad[1] = aad_len & 0xff;

	aad[2] = pos[0] & 0x8f;

	aad[3] = pos[1] & 0xc7;

	memcpy(aad + 4, hdr->addr1, 3 * ETH_ALEN);

	aad[0] = pos[0] & 0x8f;

	aad[1] = pos[1] & 0xc7;

	memcpy(aad + 2, hdr->addr1, 3 * ETH_ALEN);

	pos = (u8 *)&hdr->seq_ctl;

	aad[22] = pos[0] & 0x0f;

	aad[23] = 0; /* all bits masked */

	memset(aad + 24, 0, 8);

	aad[20] = pos[0] & 0x0f;

	aad[21] = 0; /* all bits masked */

	memset(aad + 22, 0, 8);

	if (a4_included)

		memcpy(aad + 24, hdr->addr4, ETH_ALEN);

		memcpy(aad + 22, hdr->addr4, ETH_ALEN);

	if (qc_included) {

		aad[a4_included ? 30 : 24] = qc;

		aad[a4_included ? 28 : 22] = qc;

		/* rest of QC masked */

	}



	/* Start with the first block and AAD */

	ieee80211_ccmp_aes_encrypt(tfm, b0, auth);

	xor_block(auth, aad, AES_BLOCK_LEN);

	ieee80211_ccmp_aes_encrypt(tfm, auth, auth);

	xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);

	ieee80211_ccmp_aes_encrypt(tfm, auth, auth);

	b0[0] &= 0x07;

	b0[14] = 0;

	b0[15] = 0;

	ieee80211_ccmp_aes_encrypt(tfm, b0, s0);

	return aad_len;

}



static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv)
@@ -220,36 +194,34 @@ static int ieee80211_ccmp_encrypt(struct sk_buff *skb, int hdr_len, void *priv) 


	hdr = (struct rtl_80211_hdr_4addr *)skb->data;

	if (!tcb_desc->bHwSec) {

		int blocks, last, len;

		u8 *mic;

		u8 *b0 = key->tx_b0;

		u8 *b = key->tx_b;

		u8 *e = key->tx_e;

		u8 *s0 = key->tx_s0;



		/* mic is moved to here by john */

		mic = skb_put(skb, CCMP_MIC_LEN);



		ccmp_init_blocks(key->tfm, hdr, key->tx_pn, data_len, b0, b, s0);



		blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);

		last = data_len % AES_BLOCK_LEN;



		for (i = 1; i <= blocks; i++) {

			len = (i == blocks && last) ? last : AES_BLOCK_LEN;

			/* Authentication */

			xor_block(b, pos, len);

			ieee80211_ccmp_aes_encrypt(key->tfm, b, b);

			/* Encryption, with counter */

			b0[14] = (i >> 8) & 0xff;

			b0[15] = i & 0xff;

			ieee80211_ccmp_aes_encrypt(key->tfm, b0, e);

			xor_block(pos, e, len);

			pos += len;

		}

		struct aead_request *req;

		struct scatterlist sg[2];

		u8 *aad = key->tx_aad;

		u8 iv[AES_BLOCK_LEN];

		int aad_len, ret;

		size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN;



		req = aead_request_alloc(key->tfm, GFP_ATOMIC);

		if (!req)

			return -ENOMEM;



		aad_len = ccmp_init_iv_and_aad(hdr, key->tx_pn, iv, aad);



		for (i = 0; i < CCMP_MIC_LEN; i++)

			mic[i] = b[i] ^ s0[i];

		skb_put(skb, CCMP_MIC_LEN);



		sg_init_table(sg, 2);

		sg_set_buf(&sg[0], aad, aad_len);

		sg_set_buf(&sg[1], skb->data + hdr_len + CCMP_HDR_LEN,

			   data_len + CCMP_MIC_LEN);



		aead_request_set_callback(req, 0, NULL, NULL);

		aead_request_set_ad(req, aad_len);

		aead_request_set_crypt(req, sg, sg, data_len, iv);



		ret = crypto_aead_encrypt(req);

		aead_request_free(req);



		return ret;

	}

	return 0;

}
@@ -309,33 +281,31 @@ static int ieee80211_ccmp_decrypt(struct sk_buff *skb, int hdr_len, void *priv) 
		return -4;

	}

	if (!tcb_desc->bHwSec) {

		size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN - CCMP_MIC_LEN;

		u8 *mic = skb->data + skb->len - CCMP_MIC_LEN;

		u8 *b0 = key->rx_b0;

		u8 *b = key->rx_b;

		u8 *a = key->rx_a;

		int i, blocks, last, len;



		ccmp_init_blocks(key->tfm, hdr, pn, data_len, b0, a, b);

		xor_block(mic, b, CCMP_MIC_LEN);



		blocks = DIV_ROUND_UP(data_len, AES_BLOCK_LEN);

		last = data_len % AES_BLOCK_LEN;



		for (i = 1; i <= blocks; i++) {

			len = (i == blocks && last) ? last : AES_BLOCK_LEN;

			/* Decrypt, with counter */

			b0[14] = (i >> 8) & 0xff;

			b0[15] = i & 0xff;

			ieee80211_ccmp_aes_encrypt(key->tfm, b0, b);

			xor_block(pos, b, len);

			/* Authentication */

			xor_block(a, pos, len);

			ieee80211_ccmp_aes_encrypt(key->tfm, a, a);

			pos += len;

		}

		struct aead_request *req;

		struct scatterlist sg[2];

		u8 *aad = key->rx_aad;

		u8 iv[AES_BLOCK_LEN];

		int aad_len, ret;

		size_t data_len = skb->len - hdr_len - CCMP_HDR_LEN;



		req = aead_request_alloc(key->tfm, GFP_ATOMIC);

		if (!req)

			return -ENOMEM;



		if (memcmp(mic, a, CCMP_MIC_LEN) != 0) {

		aad_len = ccmp_init_iv_and_aad(hdr, pn, iv, aad);



		sg_init_table(sg, 2);

		sg_set_buf(&sg[0], aad, aad_len);

		sg_set_buf(&sg[1], pos, data_len);



		aead_request_set_callback(req, 0, NULL, NULL);

		aead_request_set_ad(req, aad_len);

		aead_request_set_crypt(req, sg, sg, data_len, iv);



		ret = crypto_aead_decrypt(req);

		aead_request_free(req);



		if (ret) {

			if (net_ratelimit()) {

				netdev_dbg(skb->dev, "CCMP: decrypt failed: STA=%pM\n",

					   hdr->addr2);
@@ -358,12 +328,11 @@ static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv) 
{

	struct ieee80211_ccmp_data *data = priv;

	int keyidx;

	struct crypto_tfm *tfm = data->tfm;

	struct crypto_aead *tfm = data->tfm;



	keyidx = data->key_idx;

	memset(data, 0, sizeof(*data));

	data->key_idx = keyidx;

	data->tfm = tfm;

	if (len == CCMP_TK_LEN) {

		memcpy(data->key, key, CCMP_TK_LEN);

		data->key_set = 1;
@@ -375,7 +344,9 @@ static int ieee80211_ccmp_set_key(void *key, int len, u8 *seq, void *priv) 
			data->rx_pn[4] = seq[1];

			data->rx_pn[5] = seq[0];

		}

		crypto_cipher_setkey((void *)data->tfm, data->key, CCMP_TK_LEN);

		if (crypto_aead_setauthsize(tfm, CCMP_MIC_LEN) ||

		    crypto_aead_setkey(tfm, data->key, CCMP_TK_LEN))

				return -1;

	} else if (len == 0) {

		data->key_set = 0;

	} else {