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macsec: Add support for GCM-AES-256 cipher suite
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This adds support for the GCM-AES-256 cipher suite as specified in
IEEE 802.1AEbn-2011. The prepared cipher suite selection mechanism is used,
with GCM-AES-128 being the default cipher suite as defined in the standard.

Signed-off-by: Felix Walter <felix.walter@cloudandheat.com>
Cc: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Felix Walter authored and David S. Miller committed Jan 9, 2018
1 parent e8b18af commit ccfdec9
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Showing 2 changed files with 67 additions and 16 deletions.
72 changes: 59 additions & 13 deletions drivers/net/macsec.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -393,7 +393,12 @@ static struct macsec_cb *macsec_skb_cb(struct sk_buff *skb)
#define MACSEC_PORT_SCB (0x0000)
#define MACSEC_UNDEF_SCI ((__force sci_t)0xffffffffffffffffULL)

#define DEFAULT_SAK_LEN 16
#define MACSEC_GCM_AES_128_SAK_LEN 16
#define MACSEC_GCM_AES_256_SAK_LEN 32

#define MAX_SAK_LEN MACSEC_GCM_AES_256_SAK_LEN

#define DEFAULT_SAK_LEN MACSEC_GCM_AES_128_SAK_LEN
#define DEFAULT_SEND_SCI true
#define DEFAULT_ENCRYPT false
#define DEFAULT_ENCODING_SA 0
Expand Down Expand Up @@ -1600,7 +1605,7 @@ static const struct nla_policy macsec_genl_sa_policy[NUM_MACSEC_SA_ATTR] = {
[MACSEC_SA_ATTR_KEYID] = { .type = NLA_BINARY,
.len = MACSEC_KEYID_LEN, },
[MACSEC_SA_ATTR_KEY] = { .type = NLA_BINARY,
.len = MACSEC_MAX_KEY_LEN, },
.len = MAX_SAK_LEN, },
};

static int parse_sa_config(struct nlattr **attrs, struct nlattr **tb_sa)
Expand Down Expand Up @@ -2362,15 +2367,26 @@ static int nla_put_secy(struct macsec_secy *secy, struct sk_buff *skb)
{
struct macsec_tx_sc *tx_sc = &secy->tx_sc;
struct nlattr *secy_nest = nla_nest_start(skb, MACSEC_ATTR_SECY);
u64 csid;

if (!secy_nest)
return 1;

switch (secy->key_len) {
case MACSEC_GCM_AES_128_SAK_LEN:
csid = MACSEC_CIPHER_ID_GCM_AES_128;
break;
case MACSEC_GCM_AES_256_SAK_LEN:
csid = MACSEC_CIPHER_ID_GCM_AES_256;
break;
default:
goto cancel;
}

if (nla_put_sci(skb, MACSEC_SECY_ATTR_SCI, secy->sci,
MACSEC_SECY_ATTR_PAD) ||
nla_put_u64_64bit(skb, MACSEC_SECY_ATTR_CIPHER_SUITE,
MACSEC_DEFAULT_CIPHER_ID,
MACSEC_SECY_ATTR_PAD) ||
csid, MACSEC_SECY_ATTR_PAD) ||
nla_put_u8(skb, MACSEC_SECY_ATTR_ICV_LEN, secy->icv_len) ||
nla_put_u8(skb, MACSEC_SECY_ATTR_OPER, secy->operational) ||
nla_put_u8(skb, MACSEC_SECY_ATTR_PROTECT, secy->protect_frames) ||
Expand Down Expand Up @@ -3015,8 +3031,8 @@ static void macsec_setup(struct net_device *dev)
eth_zero_addr(dev->broadcast);
}

static void macsec_changelink_common(struct net_device *dev,
struct nlattr *data[])
static int macsec_changelink_common(struct net_device *dev,
struct nlattr *data[])
{
struct macsec_secy *secy;
struct macsec_tx_sc *tx_sc;
Expand Down Expand Up @@ -3056,6 +3072,22 @@ static void macsec_changelink_common(struct net_device *dev,

if (data[IFLA_MACSEC_VALIDATION])
secy->validate_frames = nla_get_u8(data[IFLA_MACSEC_VALIDATION]);

if (data[IFLA_MACSEC_CIPHER_SUITE]) {
switch (nla_get_u64(data[IFLA_MACSEC_CIPHER_SUITE])) {
case MACSEC_CIPHER_ID_GCM_AES_128:
case MACSEC_DEFAULT_CIPHER_ALT:
secy->key_len = MACSEC_GCM_AES_128_SAK_LEN;
break;
case MACSEC_CIPHER_ID_GCM_AES_256:
secy->key_len = MACSEC_GCM_AES_256_SAK_LEN;
break;
default:
return -EINVAL;
}
}

return 0;
}

static int macsec_changelink(struct net_device *dev, struct nlattr *tb[],
Expand All @@ -3071,9 +3103,7 @@ static int macsec_changelink(struct net_device *dev, struct nlattr *tb[],
data[IFLA_MACSEC_PORT])
return -EINVAL;

macsec_changelink_common(dev, data);

return 0;
return macsec_changelink_common(dev, data);
}

static void macsec_del_dev(struct macsec_dev *macsec)
Expand Down Expand Up @@ -3270,8 +3300,11 @@ static int macsec_newlink(struct net *net, struct net_device *dev,
if (err)
goto unlink;

if (data)
macsec_changelink_common(dev, data);
if (data) {
err = macsec_changelink_common(dev, data);
if (err)
goto del_dev;
}

err = register_macsec_dev(real_dev, dev);
if (err < 0)
Expand Down Expand Up @@ -3320,7 +3353,8 @@ static int macsec_validate_attr(struct nlattr *tb[], struct nlattr *data[],
}

switch (csid) {
case MACSEC_DEFAULT_CIPHER_ID:
case MACSEC_CIPHER_ID_GCM_AES_128:
case MACSEC_CIPHER_ID_GCM_AES_256:
case MACSEC_DEFAULT_CIPHER_ALT:
if (icv_len < MACSEC_MIN_ICV_LEN ||
icv_len > MACSEC_STD_ICV_LEN)
Expand Down Expand Up @@ -3390,12 +3424,24 @@ static int macsec_fill_info(struct sk_buff *skb,
{
struct macsec_secy *secy = &macsec_priv(dev)->secy;
struct macsec_tx_sc *tx_sc = &secy->tx_sc;
u64 csid;

switch (secy->key_len) {
case MACSEC_GCM_AES_128_SAK_LEN:
csid = MACSEC_CIPHER_ID_GCM_AES_128;
break;
case MACSEC_GCM_AES_256_SAK_LEN:
csid = MACSEC_CIPHER_ID_GCM_AES_256;
break;
default:
goto nla_put_failure;
}

if (nla_put_sci(skb, IFLA_MACSEC_SCI, secy->sci,
IFLA_MACSEC_PAD) ||
nla_put_u8(skb, IFLA_MACSEC_ICV_LEN, secy->icv_len) ||
nla_put_u64_64bit(skb, IFLA_MACSEC_CIPHER_SUITE,
MACSEC_DEFAULT_CIPHER_ID, IFLA_MACSEC_PAD) ||
csid, IFLA_MACSEC_PAD) ||
nla_put_u8(skb, IFLA_MACSEC_ENCODING_SA, tx_sc->encoding_sa) ||
nla_put_u8(skb, IFLA_MACSEC_ENCRYPT, tx_sc->encrypt) ||
nla_put_u8(skb, IFLA_MACSEC_PROTECT, secy->protect_frames) ||
Expand Down
11 changes: 8 additions & 3 deletions include/uapi/linux/if_macsec.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,12 +18,17 @@
#define MACSEC_GENL_NAME "macsec"
#define MACSEC_GENL_VERSION 1

#define MACSEC_MAX_KEY_LEN 128
#define MACSEC_MAX_KEY_LEN 256

#define MACSEC_KEYID_LEN 16

#define MACSEC_DEFAULT_CIPHER_ID 0x0080020001000001ULL
#define MACSEC_DEFAULT_CIPHER_ALT 0x0080C20001000001ULL
/* cipher IDs as per IEEE802.1AEbn-2011 */
#define MACSEC_CIPHER_ID_GCM_AES_128 0x0080C20001000001ULL
#define MACSEC_CIPHER_ID_GCM_AES_256 0x0080C20001000002ULL

#define MACSEC_DEFAULT_CIPHER_ID MACSEC_CIPHER_ID_GCM_AES_128
/* deprecated cipher ID for GCM-AES-128 */
#define MACSEC_DEFAULT_CIPHER_ALT 0x0080020001000001ULL

#define MACSEC_MIN_ICV_LEN 8
#define MACSEC_MAX_ICV_LEN 32
Expand Down

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