macsec.c 86.4 KB
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
 * drivers/net/macsec.c - MACsec device
 *
 * Copyright (c) 2015 Sabrina Dubroca <sd@queasysnail.net>
 */

#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/socket.h>
#include <linux/module.h>
#include <crypto/aead.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
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#include <linux/refcount.h>
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#include <net/genetlink.h>
#include <net/sock.h>
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#include <net/gro_cells.h>
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#include <uapi/linux/if_macsec.h>

typedef u64 __bitwise sci_t;

#define MACSEC_SCI_LEN 8

/* SecTAG length = macsec_eth_header without the optional SCI */
#define MACSEC_TAG_LEN 6

struct macsec_eth_header {
	struct ethhdr eth;
	/* SecTAG */
	u8  tci_an;
#if defined(__LITTLE_ENDIAN_BITFIELD)
	u8  short_length:6,
		  unused:2;
#elif defined(__BIG_ENDIAN_BITFIELD)
	u8        unused:2,
	    short_length:6;
#else
#error	"Please fix <asm/byteorder.h>"
#endif
	__be32 packet_number;
	u8 secure_channel_id[8]; /* optional */
} __packed;

#define MACSEC_TCI_VERSION 0x80
#define MACSEC_TCI_ES      0x40 /* end station */
#define MACSEC_TCI_SC      0x20 /* SCI present */
#define MACSEC_TCI_SCB     0x10 /* epon */
#define MACSEC_TCI_E       0x08 /* encryption */
#define MACSEC_TCI_C       0x04 /* changed text */
#define MACSEC_AN_MASK     0x03 /* association number */
#define MACSEC_TCI_CONFID  (MACSEC_TCI_E | MACSEC_TCI_C)

/* minimum secure data length deemed "not short", see IEEE 802.1AE-2006 9.7 */
#define MIN_NON_SHORT_LEN 48

#define GCM_AES_IV_LEN 12
#define DEFAULT_ICV_LEN 16

#define MACSEC_NUM_AN 4 /* 2 bits for the association number */

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#define for_each_rxsc(secy, sc)				\
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	for (sc = rcu_dereference_bh(secy->rx_sc);	\
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	     sc;					\
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	     sc = rcu_dereference_bh(sc->next))
#define for_each_rxsc_rtnl(secy, sc)			\
	for (sc = rtnl_dereference(secy->rx_sc);	\
	     sc;					\
	     sc = rtnl_dereference(sc->next))

struct gcm_iv {
	union {
		u8 secure_channel_id[8];
		sci_t sci;
	};
	__be32 pn;
};

/**
 * struct macsec_key - SA key
 * @id: user-provided key identifier
 * @tfm: crypto struct, key storage
 */
struct macsec_key {
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	u8 id[MACSEC_KEYID_LEN];
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	struct crypto_aead *tfm;
};

struct macsec_rx_sc_stats {
	__u64 InOctetsValidated;
	__u64 InOctetsDecrypted;
	__u64 InPktsUnchecked;
	__u64 InPktsDelayed;
	__u64 InPktsOK;
	__u64 InPktsInvalid;
	__u64 InPktsLate;
	__u64 InPktsNotValid;
	__u64 InPktsNotUsingSA;
	__u64 InPktsUnusedSA;
};

struct macsec_rx_sa_stats {
	__u32 InPktsOK;
	__u32 InPktsInvalid;
	__u32 InPktsNotValid;
	__u32 InPktsNotUsingSA;
	__u32 InPktsUnusedSA;
};

struct macsec_tx_sa_stats {
	__u32 OutPktsProtected;
	__u32 OutPktsEncrypted;
};

struct macsec_tx_sc_stats {
	__u64 OutPktsProtected;
	__u64 OutPktsEncrypted;
	__u64 OutOctetsProtected;
	__u64 OutOctetsEncrypted;
};

struct macsec_dev_stats {
	__u64 OutPktsUntagged;
	__u64 InPktsUntagged;
	__u64 OutPktsTooLong;
	__u64 InPktsNoTag;
	__u64 InPktsBadTag;
	__u64 InPktsUnknownSCI;
	__u64 InPktsNoSCI;
	__u64 InPktsOverrun;
};

/**
 * struct macsec_rx_sa - receive secure association
 * @active:
 * @next_pn: packet number expected for the next packet
 * @lock: protects next_pn manipulations
 * @key: key structure
 * @stats: per-SA stats
 */
struct macsec_rx_sa {
	struct macsec_key key;
	spinlock_t lock;
	u32 next_pn;
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	refcount_t refcnt;
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	bool active;
	struct macsec_rx_sa_stats __percpu *stats;
	struct macsec_rx_sc *sc;
	struct rcu_head rcu;
};

struct pcpu_rx_sc_stats {
	struct macsec_rx_sc_stats stats;
	struct u64_stats_sync syncp;
};

/**
 * struct macsec_rx_sc - receive secure channel
 * @sci: secure channel identifier for this SC
 * @active: channel is active
 * @sa: array of secure associations
 * @stats: per-SC stats
 */
struct macsec_rx_sc {
	struct macsec_rx_sc __rcu *next;
	sci_t sci;
	bool active;
	struct macsec_rx_sa __rcu *sa[MACSEC_NUM_AN];
	struct pcpu_rx_sc_stats __percpu *stats;
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	refcount_t refcnt;
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	struct rcu_head rcu_head;
};

/**
 * struct macsec_tx_sa - transmit secure association
 * @active:
 * @next_pn: packet number to use for the next packet
 * @lock: protects next_pn manipulations
 * @key: key structure
 * @stats: per-SA stats
 */
struct macsec_tx_sa {
	struct macsec_key key;
	spinlock_t lock;
	u32 next_pn;
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	refcount_t refcnt;
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	bool active;
	struct macsec_tx_sa_stats __percpu *stats;
	struct rcu_head rcu;
};

struct pcpu_tx_sc_stats {
	struct macsec_tx_sc_stats stats;
	struct u64_stats_sync syncp;
};

/**
 * struct macsec_tx_sc - transmit secure channel
 * @active:
 * @encoding_sa: association number of the SA currently in use
 * @encrypt: encrypt packets on transmit, or authenticate only
 * @send_sci: always include the SCI in the SecTAG
 * @end_station:
 * @scb: single copy broadcast flag
 * @sa: array of secure associations
 * @stats: stats for this TXSC
 */
struct macsec_tx_sc {
	bool active;
	u8 encoding_sa;
	bool encrypt;
	bool send_sci;
	bool end_station;
	bool scb;
	struct macsec_tx_sa __rcu *sa[MACSEC_NUM_AN];
	struct pcpu_tx_sc_stats __percpu *stats;
};

#define MACSEC_VALIDATE_DEFAULT MACSEC_VALIDATE_STRICT

/**
 * struct macsec_secy - MACsec Security Entity
 * @netdev: netdevice for this SecY
 * @n_rx_sc: number of receive secure channels configured on this SecY
 * @sci: secure channel identifier used for tx
 * @key_len: length of keys used by the cipher suite
 * @icv_len: length of ICV used by the cipher suite
 * @validate_frames: validation mode
 * @operational: MAC_Operational flag
 * @protect_frames: enable protection for this SecY
 * @replay_protect: enable packet number checks on receive
 * @replay_window: size of the replay window
 * @tx_sc: transmit secure channel
 * @rx_sc: linked list of receive secure channels
 */
struct macsec_secy {
	struct net_device *netdev;
	unsigned int n_rx_sc;
	sci_t sci;
	u16 key_len;
	u16 icv_len;
	enum macsec_validation_type validate_frames;
	bool operational;
	bool protect_frames;
	bool replay_protect;
	u32 replay_window;
	struct macsec_tx_sc tx_sc;
	struct macsec_rx_sc __rcu *rx_sc;
};

struct pcpu_secy_stats {
	struct macsec_dev_stats stats;
	struct u64_stats_sync syncp;
};

/**
 * struct macsec_dev - private data
 * @secy: SecY config
 * @real_dev: pointer to underlying netdevice
 * @stats: MACsec device stats
 * @secys: linked list of SecY's on the underlying device
 */
struct macsec_dev {
	struct macsec_secy secy;
	struct net_device *real_dev;
	struct pcpu_secy_stats __percpu *stats;
	struct list_head secys;
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	struct gro_cells gro_cells;
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	unsigned int nest_level;
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};

/**
 * struct macsec_rxh_data - rx_handler private argument
 * @secys: linked list of SecY's on this underlying device
 */
struct macsec_rxh_data {
	struct list_head secys;
};

static struct macsec_dev *macsec_priv(const struct net_device *dev)
{
	return (struct macsec_dev *)netdev_priv(dev);
}

static struct macsec_rxh_data *macsec_data_rcu(const struct net_device *dev)
{
	return rcu_dereference_bh(dev->rx_handler_data);
}

static struct macsec_rxh_data *macsec_data_rtnl(const struct net_device *dev)
{
	return rtnl_dereference(dev->rx_handler_data);
}

struct macsec_cb {
	struct aead_request *req;
	union {
		struct macsec_tx_sa *tx_sa;
		struct macsec_rx_sa *rx_sa;
	};
	u8 assoc_num;
	bool valid;
	bool has_sci;
};

static struct macsec_rx_sa *macsec_rxsa_get(struct macsec_rx_sa __rcu *ptr)
{
	struct macsec_rx_sa *sa = rcu_dereference_bh(ptr);

	if (!sa || !sa->active)
		return NULL;

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	if (!refcount_inc_not_zero(&sa->refcnt))
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		return NULL;

	return sa;
}

static void free_rx_sc_rcu(struct rcu_head *head)
{
	struct macsec_rx_sc *rx_sc = container_of(head, struct macsec_rx_sc, rcu_head);

	free_percpu(rx_sc->stats);
	kfree(rx_sc);
}

static struct macsec_rx_sc *macsec_rxsc_get(struct macsec_rx_sc *sc)
{
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	return refcount_inc_not_zero(&sc->refcnt) ? sc : NULL;
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}

static void macsec_rxsc_put(struct macsec_rx_sc *sc)
{
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	if (refcount_dec_and_test(&sc->refcnt))
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		call_rcu(&sc->rcu_head, free_rx_sc_rcu);
}

static void free_rxsa(struct rcu_head *head)
{
	struct macsec_rx_sa *sa = container_of(head, struct macsec_rx_sa, rcu);

	crypto_free_aead(sa->key.tfm);
	free_percpu(sa->stats);
	kfree(sa);
}

static void macsec_rxsa_put(struct macsec_rx_sa *sa)
{
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	if (refcount_dec_and_test(&sa->refcnt))
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		call_rcu(&sa->rcu, free_rxsa);
}

static struct macsec_tx_sa *macsec_txsa_get(struct macsec_tx_sa __rcu *ptr)
{
	struct macsec_tx_sa *sa = rcu_dereference_bh(ptr);

	if (!sa || !sa->active)
		return NULL;

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	if (!refcount_inc_not_zero(&sa->refcnt))
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		return NULL;

	return sa;
}

static void free_txsa(struct rcu_head *head)
{
	struct macsec_tx_sa *sa = container_of(head, struct macsec_tx_sa, rcu);

	crypto_free_aead(sa->key.tfm);
	free_percpu(sa->stats);
	kfree(sa);
}

static void macsec_txsa_put(struct macsec_tx_sa *sa)
{
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	if (refcount_dec_and_test(&sa->refcnt))
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		call_rcu(&sa->rcu, free_txsa);
}

static struct macsec_cb *macsec_skb_cb(struct sk_buff *skb)
{
	BUILD_BUG_ON(sizeof(struct macsec_cb) > sizeof(skb->cb));
	return (struct macsec_cb *)skb->cb;
}

#define MACSEC_PORT_ES (htons(0x0001))
#define MACSEC_PORT_SCB (0x0000)
#define MACSEC_UNDEF_SCI ((__force sci_t)0xffffffffffffffffULL)

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#define MACSEC_GCM_AES_128_SAK_LEN 16
#define MACSEC_GCM_AES_256_SAK_LEN 32

#define DEFAULT_SAK_LEN MACSEC_GCM_AES_128_SAK_LEN
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#define DEFAULT_SEND_SCI true
#define DEFAULT_ENCRYPT false
#define DEFAULT_ENCODING_SA 0

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static bool send_sci(const struct macsec_secy *secy)
{
	const struct macsec_tx_sc *tx_sc = &secy->tx_sc;

	return tx_sc->send_sci ||
		(secy->n_rx_sc > 1 && !tx_sc->end_station && !tx_sc->scb);
}

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static sci_t make_sci(u8 *addr, __be16 port)
{
	sci_t sci;

	memcpy(&sci, addr, ETH_ALEN);
	memcpy(((char *)&sci) + ETH_ALEN, &port, sizeof(port));

	return sci;
}

static sci_t macsec_frame_sci(struct macsec_eth_header *hdr, bool sci_present)
{
	sci_t sci;

	if (sci_present)
		memcpy(&sci, hdr->secure_channel_id,
		       sizeof(hdr->secure_channel_id));
	else
		sci = make_sci(hdr->eth.h_source, MACSEC_PORT_ES);

	return sci;
}

static unsigned int macsec_sectag_len(bool sci_present)
{
	return MACSEC_TAG_LEN + (sci_present ? MACSEC_SCI_LEN : 0);
}

static unsigned int macsec_hdr_len(bool sci_present)
{
	return macsec_sectag_len(sci_present) + ETH_HLEN;
}

static unsigned int macsec_extra_len(bool sci_present)
{
	return macsec_sectag_len(sci_present) + sizeof(__be16);
}

/* Fill SecTAG according to IEEE 802.1AE-2006 10.5.3 */
static void macsec_fill_sectag(struct macsec_eth_header *h,
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			       const struct macsec_secy *secy, u32 pn,
			       bool sci_present)
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{
	const struct macsec_tx_sc *tx_sc = &secy->tx_sc;

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	memset(&h->tci_an, 0, macsec_sectag_len(sci_present));
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	h->eth.h_proto = htons(ETH_P_MACSEC);

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	if (sci_present) {
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		h->tci_an |= MACSEC_TCI_SC;
		memcpy(&h->secure_channel_id, &secy->sci,
		       sizeof(h->secure_channel_id));
	} else {
		if (tx_sc->end_station)
			h->tci_an |= MACSEC_TCI_ES;
		if (tx_sc->scb)
			h->tci_an |= MACSEC_TCI_SCB;
	}

	h->packet_number = htonl(pn);

	/* with GCM, C/E clear for !encrypt, both set for encrypt */
	if (tx_sc->encrypt)
		h->tci_an |= MACSEC_TCI_CONFID;
	else if (secy->icv_len != DEFAULT_ICV_LEN)
		h->tci_an |= MACSEC_TCI_C;

	h->tci_an |= tx_sc->encoding_sa;
}

static void macsec_set_shortlen(struct macsec_eth_header *h, size_t data_len)
{
	if (data_len < MIN_NON_SHORT_LEN)
		h->short_length = data_len;
}

/* validate MACsec packet according to IEEE 802.1AE-2006 9.12 */
static bool macsec_validate_skb(struct sk_buff *skb, u16 icv_len)
{
	struct macsec_eth_header *h = (struct macsec_eth_header *)skb->data;
	int len = skb->len - 2 * ETH_ALEN;
	int extra_len = macsec_extra_len(!!(h->tci_an & MACSEC_TCI_SC)) + icv_len;

	/* a) It comprises at least 17 octets */
	if (skb->len <= 16)
		return false;

	/* b) MACsec EtherType: already checked */

	/* c) V bit is clear */
	if (h->tci_an & MACSEC_TCI_VERSION)
		return false;

	/* d) ES or SCB => !SC */
	if ((h->tci_an & MACSEC_TCI_ES || h->tci_an & MACSEC_TCI_SCB) &&
	    (h->tci_an & MACSEC_TCI_SC))
		return false;

	/* e) Bits 7 and 8 of octet 4 of the SecTAG are clear */
	if (h->unused)
		return false;

	/* rx.pn != 0 (figure 10-5) */
	if (!h->packet_number)
		return false;

	/* length check, f) g) h) i) */
	if (h->short_length)
		return len == extra_len + h->short_length;
	return len >= extra_len + MIN_NON_SHORT_LEN;
}

#define MACSEC_NEEDED_HEADROOM (macsec_extra_len(true))
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#define MACSEC_NEEDED_TAILROOM MACSEC_STD_ICV_LEN
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static void macsec_fill_iv(unsigned char *iv, sci_t sci, u32 pn)
{
	struct gcm_iv *gcm_iv = (struct gcm_iv *)iv;

	gcm_iv->sci = sci;
	gcm_iv->pn = htonl(pn);
}

static struct macsec_eth_header *macsec_ethhdr(struct sk_buff *skb)
{
	return (struct macsec_eth_header *)skb_mac_header(skb);
}

static u32 tx_sa_update_pn(struct macsec_tx_sa *tx_sa, struct macsec_secy *secy)
{
	u32 pn;

	spin_lock_bh(&tx_sa->lock);
	pn = tx_sa->next_pn;

	tx_sa->next_pn++;
	if (tx_sa->next_pn == 0) {
		pr_debug("PN wrapped, transitioning to !oper\n");
		tx_sa->active = false;
		if (secy->protect_frames)
			secy->operational = false;
	}
	spin_unlock_bh(&tx_sa->lock);

	return pn;
}

static void macsec_encrypt_finish(struct sk_buff *skb, struct net_device *dev)
{
	struct macsec_dev *macsec = netdev_priv(dev);

	skb->dev = macsec->real_dev;
	skb_reset_mac_header(skb);
	skb->protocol = eth_hdr(skb)->h_proto;
}

static void macsec_count_tx(struct sk_buff *skb, struct macsec_tx_sc *tx_sc,
			    struct macsec_tx_sa *tx_sa)
{
	struct pcpu_tx_sc_stats *txsc_stats = this_cpu_ptr(tx_sc->stats);

	u64_stats_update_begin(&txsc_stats->syncp);
	if (tx_sc->encrypt) {
		txsc_stats->stats.OutOctetsEncrypted += skb->len;
		txsc_stats->stats.OutPktsEncrypted++;
		this_cpu_inc(tx_sa->stats->OutPktsEncrypted);
	} else {
		txsc_stats->stats.OutOctetsProtected += skb->len;
		txsc_stats->stats.OutPktsProtected++;
		this_cpu_inc(tx_sa->stats->OutPktsProtected);
	}
	u64_stats_update_end(&txsc_stats->syncp);
}

static void count_tx(struct net_device *dev, int ret, int len)
{
	if (likely(ret == NET_XMIT_SUCCESS || ret == NET_XMIT_CN)) {
		struct pcpu_sw_netstats *stats = this_cpu_ptr(dev->tstats);

		u64_stats_update_begin(&stats->syncp);
		stats->tx_packets++;
		stats->tx_bytes += len;
		u64_stats_update_end(&stats->syncp);
	}
}

static void macsec_encrypt_done(struct crypto_async_request *base, int err)
{
	struct sk_buff *skb = base->data;
	struct net_device *dev = skb->dev;
	struct macsec_dev *macsec = macsec_priv(dev);
	struct macsec_tx_sa *sa = macsec_skb_cb(skb)->tx_sa;
	int len, ret;

	aead_request_free(macsec_skb_cb(skb)->req);

	rcu_read_lock_bh();
	macsec_encrypt_finish(skb, dev);
	macsec_count_tx(skb, &macsec->secy.tx_sc, macsec_skb_cb(skb)->tx_sa);
	len = skb->len;
	ret = dev_queue_xmit(skb);
	count_tx(dev, ret, len);
	rcu_read_unlock_bh();

	macsec_txsa_put(sa);
	dev_put(dev);
}

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static struct aead_request *macsec_alloc_req(struct crypto_aead *tfm,
					     unsigned char **iv,
618
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					     struct scatterlist **sg,
					     int num_frags)
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{
	size_t size, iv_offset, sg_offset;
	struct aead_request *req;
	void *tmp;

	size = sizeof(struct aead_request) + crypto_aead_reqsize(tfm);
	iv_offset = size;
	size += GCM_AES_IV_LEN;

	size = ALIGN(size, __alignof__(struct scatterlist));
	sg_offset = size;
631
	size += sizeof(struct scatterlist) * num_frags;
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	tmp = kmalloc(size, GFP_ATOMIC);
	if (!tmp)
		return NULL;

	*iv = (unsigned char *)(tmp + iv_offset);
	*sg = (struct scatterlist *)(tmp + sg_offset);
	req = tmp;

	aead_request_set_tfm(req, tfm);

	return req;
}

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static struct sk_buff *macsec_encrypt(struct sk_buff *skb,
				      struct net_device *dev)
{
	int ret;
650
	struct scatterlist *sg;
651
	struct sk_buff *trailer;
652
	unsigned char *iv;
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	struct ethhdr *eth;
	struct macsec_eth_header *hh;
	size_t unprotected_len;
	struct aead_request *req;
	struct macsec_secy *secy;
	struct macsec_tx_sc *tx_sc;
	struct macsec_tx_sa *tx_sa;
	struct macsec_dev *macsec = macsec_priv(dev);
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	bool sci_present;
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	u32 pn;

	secy = &macsec->secy;
	tx_sc = &secy->tx_sc;

	/* 10.5.1 TX SA assignment */
	tx_sa = macsec_txsa_get(tx_sc->sa[tx_sc->encoding_sa]);
	if (!tx_sa) {
		secy->operational = false;
		kfree_skb(skb);
		return ERR_PTR(-EINVAL);
	}

	if (unlikely(skb_headroom(skb) < MACSEC_NEEDED_HEADROOM ||
		     skb_tailroom(skb) < MACSEC_NEEDED_TAILROOM)) {
		struct sk_buff *nskb = skb_copy_expand(skb,
						       MACSEC_NEEDED_HEADROOM,
						       MACSEC_NEEDED_TAILROOM,
						       GFP_ATOMIC);
		if (likely(nskb)) {
			consume_skb(skb);
			skb = nskb;
		} else {
			macsec_txsa_put(tx_sa);
			kfree_skb(skb);
			return ERR_PTR(-ENOMEM);
		}
	} else {
		skb = skb_unshare(skb, GFP_ATOMIC);
		if (!skb) {
			macsec_txsa_put(tx_sa);
			return ERR_PTR(-ENOMEM);
		}
	}

	unprotected_len = skb->len;
	eth = eth_hdr(skb);
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	sci_present = send_sci(secy);
700
	hh = skb_push(skb, macsec_extra_len(sci_present));
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	memmove(hh, eth, 2 * ETH_ALEN);

	pn = tx_sa_update_pn(tx_sa, secy);
	if (pn == 0) {
		macsec_txsa_put(tx_sa);
		kfree_skb(skb);
		return ERR_PTR(-ENOLINK);
	}
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	macsec_fill_sectag(hh, secy, pn, sci_present);
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	macsec_set_shortlen(hh, unprotected_len - 2 * ETH_ALEN);

	skb_put(skb, secy->icv_len);

	if (skb->len - ETH_HLEN > macsec_priv(dev)->real_dev->mtu) {
		struct pcpu_secy_stats *secy_stats = this_cpu_ptr(macsec->stats);

		u64_stats_update_begin(&secy_stats->syncp);
		secy_stats->stats.OutPktsTooLong++;
		u64_stats_update_end(&secy_stats->syncp);

		macsec_txsa_put(tx_sa);
		kfree_skb(skb);
		return ERR_PTR(-EINVAL);
	}

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	ret = skb_cow_data(skb, 0, &trailer);
	if (unlikely(ret < 0)) {
		macsec_txsa_put(tx_sa);
		kfree_skb(skb);
		return ERR_PTR(ret);
	}

	req = macsec_alloc_req(tx_sa->key.tfm, &iv, &sg, ret);
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	if (!req) {
		macsec_txsa_put(tx_sa);
		kfree_skb(skb);
		return ERR_PTR(-ENOMEM);
	}

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741
	macsec_fill_iv(iv, secy->sci, pn);

742
	sg_init_table(sg, ret);
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	ret = skb_to_sgvec(skb, sg, 0, skb->len);
	if (unlikely(ret < 0)) {
745
		aead_request_free(req);
746
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749
		macsec_txsa_put(tx_sa);
		kfree_skb(skb);
		return ERR_PTR(ret);
	}
750
751

	if (tx_sc->encrypt) {
752
		int len = skb->len - macsec_hdr_len(sci_present) -
753
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			  secy->icv_len;
		aead_request_set_crypt(req, sg, sg, len, iv);
755
		aead_request_set_ad(req, macsec_hdr_len(sci_present));
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	} else {
		aead_request_set_crypt(req, sg, sg, 0, iv);
		aead_request_set_ad(req, skb->len - secy->icv_len);
	}

	macsec_skb_cb(skb)->req = req;
	macsec_skb_cb(skb)->tx_sa = tx_sa;
	aead_request_set_callback(req, 0, macsec_encrypt_done, skb);

	dev_hold(skb->dev);
	ret = crypto_aead_encrypt(req);
	if (ret == -EINPROGRESS) {
		return ERR_PTR(ret);
	} else if (ret != 0) {
		dev_put(skb->dev);
		kfree_skb(skb);
		aead_request_free(req);
		macsec_txsa_put(tx_sa);
		return ERR_PTR(-EINVAL);
	}

	dev_put(skb->dev);
	aead_request_free(req);
	macsec_txsa_put(tx_sa);

	return skb;
}

static bool macsec_post_decrypt(struct sk_buff *skb, struct macsec_secy *secy, u32 pn)
{
	struct macsec_rx_sa *rx_sa = macsec_skb_cb(skb)->rx_sa;
	struct pcpu_rx_sc_stats *rxsc_stats = this_cpu_ptr(rx_sa->sc->stats);
	struct macsec_eth_header *hdr = macsec_ethhdr(skb);
	u32 lowest_pn = 0;

	spin_lock(&rx_sa->lock);
	if (rx_sa->next_pn >= secy->replay_window)
		lowest_pn = rx_sa->next_pn - secy->replay_window;

	/* Now perform replay protection check again
	 * (see IEEE 802.1AE-2006 figure 10-5)
	 */
	if (secy->replay_protect && pn < lowest_pn) {
		spin_unlock(&rx_sa->lock);
		u64_stats_update_begin(&rxsc_stats->syncp);
		rxsc_stats->stats.InPktsLate++;
		u64_stats_update_end(&rxsc_stats->syncp);
		return false;
	}

	if (secy->validate_frames != MACSEC_VALIDATE_DISABLED) {
		u64_stats_update_begin(&rxsc_stats->syncp);
		if (hdr->tci_an & MACSEC_TCI_E)
			rxsc_stats->stats.InOctetsDecrypted += skb->len;
		else
			rxsc_stats->stats.InOctetsValidated += skb->len;
		u64_stats_update_end(&rxsc_stats->syncp);
	}

	if (!macsec_skb_cb(skb)->valid) {
		spin_unlock(&rx_sa->lock);

		/* 10.6.5 */
		if (hdr->tci_an & MACSEC_TCI_C ||
		    secy->validate_frames == MACSEC_VALIDATE_STRICT) {
			u64_stats_update_begin(&rxsc_stats->syncp);
			rxsc_stats->stats.InPktsNotValid++;
			u64_stats_update_end(&rxsc_stats->syncp);
			return false;
		}

		u64_stats_update_begin(&rxsc_stats->syncp);
		if (secy->validate_frames == MACSEC_VALIDATE_CHECK) {
			rxsc_stats->stats.InPktsInvalid++;
			this_cpu_inc(rx_sa->stats->InPktsInvalid);
		} else if (pn < lowest_pn) {
			rxsc_stats->stats.InPktsDelayed++;
		} else {
			rxsc_stats->stats.InPktsUnchecked++;
		}
		u64_stats_update_end(&rxsc_stats->syncp);
	} else {
		u64_stats_update_begin(&rxsc_stats->syncp);
		if (pn < lowest_pn) {
			rxsc_stats->stats.InPktsDelayed++;
		} else {
			rxsc_stats->stats.InPktsOK++;
			this_cpu_inc(rx_sa->stats->InPktsOK);
		}
		u64_stats_update_end(&rxsc_stats->syncp);

		if (pn >= rx_sa->next_pn)
			rx_sa->next_pn = pn + 1;
		spin_unlock(&rx_sa->lock);
	}

	return true;
}

static void macsec_reset_skb(struct sk_buff *skb, struct net_device *dev)
{
	skb->pkt_type = PACKET_HOST;
	skb->protocol = eth_type_trans(skb, dev);

	skb_reset_network_header(skb);
	if (!skb_transport_header_was_set(skb))
		skb_reset_transport_header(skb);
	skb_reset_mac_len(skb);
}

static void macsec_finalize_skb(struct sk_buff *skb, u8 icv_len, u8 hdr_len)
{
868
	skb->ip_summed = CHECKSUM_NONE;
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
	memmove(skb->data + hdr_len, skb->data, 2 * ETH_ALEN);
	skb_pull(skb, hdr_len);
	pskb_trim_unique(skb, skb->len - icv_len);
}

static void count_rx(struct net_device *dev, int len)
{
	struct pcpu_sw_netstats *stats = this_cpu_ptr(dev->tstats);

	u64_stats_update_begin(&stats->syncp);
	stats->rx_packets++;
	stats->rx_bytes += len;
	u64_stats_update_end(&stats->syncp);
}

static void macsec_decrypt_done(struct crypto_async_request *base, int err)
{
	struct sk_buff *skb = base->data;
	struct net_device *dev = skb->dev;
	struct macsec_dev *macsec = macsec_priv(dev);
	struct macsec_rx_sa *rx_sa = macsec_skb_cb(skb)->rx_sa;
890
	struct macsec_rx_sc *rx_sc = rx_sa->sc;
891
	int len;
892
893
894
895
	u32 pn;

	aead_request_free(macsec_skb_cb(skb)->req);

896
897
898
	if (!err)
		macsec_skb_cb(skb)->valid = true;

899
900
901
902
903
904
905
906
907
908
909
910
911
	rcu_read_lock_bh();
	pn = ntohl(macsec_ethhdr(skb)->packet_number);
	if (!macsec_post_decrypt(skb, &macsec->secy, pn)) {
		rcu_read_unlock_bh();
		kfree_skb(skb);
		goto out;
	}

	macsec_finalize_skb(skb, macsec->secy.icv_len,
			    macsec_extra_len(macsec_skb_cb(skb)->has_sci));
	macsec_reset_skb(skb, macsec->secy.netdev);

	len = skb->len;
912
	if (gro_cells_receive(&macsec->gro_cells, skb) == NET_RX_SUCCESS)
913
914
915
916
917
918
		count_rx(dev, len);

	rcu_read_unlock_bh();

out:
	macsec_rxsa_put(rx_sa);
919
	macsec_rxsc_put(rx_sc);
920
921
922
923
924
925
926
927
928
929
	dev_put(dev);
}

static struct sk_buff *macsec_decrypt(struct sk_buff *skb,
				      struct net_device *dev,
				      struct macsec_rx_sa *rx_sa,
				      sci_t sci,
				      struct macsec_secy *secy)
{
	int ret;
930
	struct scatterlist *sg;
931
	struct sk_buff *trailer;
932
	unsigned char *iv;
933
934
935
936
937
938
939
	struct aead_request *req;
	struct macsec_eth_header *hdr;
	u16 icv_len = secy->icv_len;

	macsec_skb_cb(skb)->valid = false;
	skb = skb_share_check(skb, GFP_ATOMIC);
	if (!skb)
940
		return ERR_PTR(-ENOMEM);
941

942
943
944
945
946
947
	ret = skb_cow_data(skb, 0, &trailer);
	if (unlikely(ret < 0)) {
		kfree_skb(skb);
		return ERR_PTR(ret);
	}
	req = macsec_alloc_req(rx_sa->key.tfm, &iv, &sg, ret);
948
949
	if (!req) {
		kfree_skb(skb);
950
		return ERR_PTR(-ENOMEM);
951
952
953
954
955
	}

	hdr = (struct macsec_eth_header *)skb->data;
	macsec_fill_iv(iv, sci, ntohl(hdr->packet_number));

956
	sg_init_table(sg, ret);
957
958
	ret = skb_to_sgvec(skb, sg, 0, skb->len);
	if (unlikely(ret < 0)) {
959
		aead_request_free(req);
960
961
962
		kfree_skb(skb);
		return ERR_PTR(ret);
	}
963
964
965
966
967
968
969
970
971
972
973
974

	if (hdr->tci_an & MACSEC_TCI_E) {
		/* confidentiality: ethernet + macsec header
		 * authenticated, encrypted payload
		 */
		int len = skb->len - macsec_hdr_len(macsec_skb_cb(skb)->has_sci);

		aead_request_set_crypt(req, sg, sg, len, iv);
		aead_request_set_ad(req, macsec_hdr_len(macsec_skb_cb(skb)->has_sci));
		skb = skb_unshare(skb, GFP_ATOMIC);
		if (!skb) {
			aead_request_free(req);
975
			return ERR_PTR(-ENOMEM);
976
977
978
979
980
981
982
983
984
985
986
987
988
989
		}
	} else {
		/* integrity only: all headers + data authenticated */
		aead_request_set_crypt(req, sg, sg, icv_len, iv);
		aead_request_set_ad(req, skb->len - icv_len);
	}

	macsec_skb_cb(skb)->req = req;
	skb->dev = dev;
	aead_request_set_callback(req, 0, macsec_decrypt_done, skb);

	dev_hold(dev);
	ret = crypto_aead_decrypt(req);
	if (ret == -EINPROGRESS) {
990
		return ERR_PTR(ret);
991
992
993
994
995
996
	} else if (ret != 0) {
		/* decryption/authentication failed
		 * 10.6 if validateFrames is disabled, deliver anyway
		 */
		if (ret != -EBADMSG) {
			kfree_skb(skb);
997
			skb = ERR_PTR(ret);
998
999
1000
		}
	} else {
		macsec_skb_cb(skb)->valid = true;