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macsec: fix configurable ICV length

PATCH In review Davide Caratti 3 participants 6 messages Jul 22, 2016 – Jul 25, 2016

Subsystems (3)
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Davide Caratti

author
#0 lore raw

cover macsec: fix configurable ICV length

This series provides a fix for macsec configurable ICV length. The maximum length of ICV element has been made compliant to IEEE 802.1AE, and error reporting in case of cipher suite configuration failure has been improved. Finally, a test has been added to netlink verify() callback in order to avoid creation of macsec interfaces having user-provided ICV length values that are not supported by the cipher suite.

Signed-off-by Davide Caratti <[email protected]>

Davide Caratti (3):
macsec: limit ICV length to 16 octets
macsec: fix error codes when a SA is created
macsec: validate ICV length on link creation

 drivers/net/macsec.c           | 76 ++++++++++++++++++++++++++++--------------
 include/uapi/linux/if_macsec.h |  2 ++
 2 files changed, 53 insertions(+), 25 deletions(-)
Signature · 1 line
2.5.5
author
#1 lore raw

PATCH 1/3 macsec: limit ICV length to 16 octets

IEEE 802.1AE-2006 standard recommends that the ICV element in a MACsec frame should not exceed 16 octets: add MACSEC_STD_ICV_LEN in uapi definitions accordingly, and avoid accepting configurations where the ICV length exceeds the standard value. Leave definition of MACSEC_MAX_ICV_LEN unchanged for backwards compatibility with userspace programs.

Fixes dece8d2b78d1 ("uapi: add MACsec bits")
Signed-off-by Davide Caratti <[email protected]>
---
 drivers/net/macsec.c           | 4 ++--
 include/uapi/linux/if_macsec.h | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)
drivers/net/macsec.c +2 -2
index 8bcd78f..7c0e732 100644
@@ -508,7 +508,7 @@ static bool macsec_validate_skb(struct sk_buff *skb, u16 icv_len)
 }
 
 #define MACSEC_NEEDED_HEADROOM (macsec_extra_len(true))
-#define MACSEC_NEEDED_TAILROOM MACSEC_MAX_ICV_LEN
+#define MACSEC_NEEDED_TAILROOM MACSEC_STD_ICV_LEN
 
 static void macsec_fill_iv(unsigned char *iv, sci_t sci, u32 pn)
 {

@@ -3199,7 +3199,7 @@ static int macsec_validate_attr(struct nlattr *tb[], struct nlattr *data[])
 	case MACSEC_DEFAULT_CIPHER_ID:
 	case MACSEC_DEFAULT_CIPHER_ALT:
 		if (icv_len < MACSEC_MIN_ICV_LEN ||
-		    icv_len > MACSEC_MAX_ICV_LEN)
+		    icv_len > MACSEC_STD_ICV_LEN)
 			return -EINVAL;
 		break;
 	default:
include/uapi/linux/if_macsec.h +2 -0
index f7d4831..02fc49c 100644
@@ -26,6 +26,8 @@
 
 #define MACSEC_MIN_ICV_LEN 8
 #define MACSEC_MAX_ICV_LEN 32
+/* upper limit for ICV length as recommended by IEEE802.1AE-2006 */
+#define MACSEC_STD_ICV_LEN 16
 
 enum macsec_attrs {
 	MACSEC_ATTR_UNSPEC,
Signature · 1 line
2.5.5
author
#2 lore raw

PATCH 2/3 macsec: fix error codes when a SA is created

In reply to Davide Caratti

preserve the return value of AEAD functions that are called when a SA is created, to avoid inappropriate display of "RTNETLINK answers: Cannot allocate memory" message.

Signed-off-by Davide Caratti <[email protected]>
---
 drivers/net/macsec.c | 58 ++++++++++++++++++++++++++++++++--------------------
 1 file changed, 36 insertions(+), 22 deletions(-)
drivers/net/macsec.c +36 -22
index 7c0e732..6d45ba6 100644
@@ -1263,22 +1263,22 @@ static struct crypto_aead *macsec_alloc_tfm(char *key, int key_len, int icv_len)
 	int ret;
 
 	tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
-	if (!tfm || IS_ERR(tfm))
-		return NULL;
+
+	if (IS_ERR(tfm))
+		return tfm;
 
 	ret = crypto_aead_setkey(tfm, key, key_len);
-	if (ret < 0) {
-		crypto_free_aead(tfm);
-		return NULL;
-	}
+	if (ret < 0)
+		goto fail;
 
 	ret = crypto_aead_setauthsize(tfm, icv_len);
-	if (ret < 0) {
-		crypto_free_aead(tfm);
-		return NULL;
-	}
+	if (ret < 0)
+		goto fail;
 
 	return tfm;
+fail:
+	crypto_free_aead(tfm);
+	return ERR_PTR(ret);
 }
 
 static int init_rx_sa(struct macsec_rx_sa *rx_sa, char *sak, int key_len,

@@ -1286,12 +1286,12 @@ static int init_rx_sa(struct macsec_rx_sa *rx_sa, char *sak, int key_len,
 {
 	rx_sa->stats = alloc_percpu(struct macsec_rx_sa_stats);
 	if (!rx_sa->stats)
-		return -1;
+		return -ENOMEM;
 
 	rx_sa->key.tfm = macsec_alloc_tfm(sak, key_len, icv_len);
-	if (!rx_sa->key.tfm) {
+	if (IS_ERR(rx_sa->key.tfm)) {
 		free_percpu(rx_sa->stats);
-		return -1;
+		return PTR_ERR(rx_sa->key.tfm);
 	}
 
 	rx_sa->active = false;

@@ -1384,12 +1384,12 @@ static int init_tx_sa(struct macsec_tx_sa *tx_sa, char *sak, int key_len,
 {
 	tx_sa->stats = alloc_percpu(struct macsec_tx_sa_stats);
 	if (!tx_sa->stats)
-		return -1;
+		return -ENOMEM;
 
 	tx_sa->key.tfm = macsec_alloc_tfm(sak, key_len, icv_len);
-	if (!tx_sa->key.tfm) {
+	if (IS_ERR(tx_sa->key.tfm)) {
 		free_percpu(tx_sa->stats);
-		return -1;
+		return PTR_ERR(tx_sa->key.tfm);
 	}
 
 	tx_sa->active = false;

@@ -1622,6 +1622,7 @@ static int macsec_add_rxsa(struct sk_buff *skb, struct genl_info *info)
 	unsigned char assoc_num;
 	struct nlattr *tb_rxsc[MACSEC_RXSC_ATTR_MAX + 1];
 	struct nlattr *tb_sa[MACSEC_SA_ATTR_MAX + 1];
+	int err;
 
 	if (!attrs[MACSEC_ATTR_IFINDEX])
 		return -EINVAL;

@@ -1658,13 +1659,19 @@ static int macsec_add_rxsa(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	rx_sa = kmalloc(sizeof(*rx_sa), GFP_KERNEL);
-	if (!rx_sa || init_rx_sa(rx_sa, nla_data(tb_sa[MACSEC_SA_ATTR_KEY]),
-				 secy->key_len, secy->icv_len)) {
-		kfree(rx_sa);
+	if (!rx_sa) {
 		rtnl_unlock();
 		return -ENOMEM;
 	}
 
+	err = init_rx_sa(rx_sa, nla_data(tb_sa[MACSEC_SA_ATTR_KEY]),
+			 secy->key_len, secy->icv_len);
+	if (err < 0) {
+		kfree(rx_sa);
+		rtnl_unlock();
+		return err;
+	}
+
 	if (tb_sa[MACSEC_SA_ATTR_PN]) {
 		spin_lock_bh(&rx_sa->lock);
 		rx_sa->next_pn = nla_get_u32(tb_sa[MACSEC_SA_ATTR_PN]);

@@ -1770,6 +1777,7 @@ static int macsec_add_txsa(struct sk_buff *skb, struct genl_info *info)
 	struct macsec_tx_sa *tx_sa;
 	unsigned char assoc_num;
 	struct nlattr *tb_sa[MACSEC_SA_ATTR_MAX + 1];
+	int err;
 
 	if (!attrs[MACSEC_ATTR_IFINDEX])
 		return -EINVAL;

@@ -1806,13 +1814,19 @@ static int macsec_add_txsa(struct sk_buff *skb, struct genl_info *info)
 	}
 
 	tx_sa = kmalloc(sizeof(*tx_sa), GFP_KERNEL);
-	if (!tx_sa || init_tx_sa(tx_sa, nla_data(tb_sa[MACSEC_SA_ATTR_KEY]),
-				 secy->key_len, secy->icv_len)) {
-		kfree(tx_sa);
+	if (!tx_sa) {
 		rtnl_unlock();
 		return -ENOMEM;
 	}
 
+	err = init_tx_sa(tx_sa, nla_data(tb_sa[MACSEC_SA_ATTR_KEY]),
+			 secy->key_len, secy->icv_len);
+	if (err < 0) {
+		kfree(tx_sa);
+		rtnl_unlock();
+		return err;
+	}
+
 	nla_memcpy(tx_sa->key.id, tb_sa[MACSEC_SA_ATTR_KEYID], MACSEC_KEYID_LEN);
 
 	spin_lock_bh(&tx_sa->lock);
Signature · 1 line
2.5.5
author
#3 lore raw

PATCH 3/3 macsec: validate ICV length on link creation

In reply to Davide Caratti

Test the cipher suite initialization in case ICV length has a value different than its default. If this test fails, creation of a new macsec link will also fail. This avoids situations where further security associations can't be added due to failures of crypto_aead_setauthsize(), caused by unsupported user-provided values of the ICV length.

Signed-off-by Davide Caratti <[email protected]>
---
 drivers/net/macsec.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)
drivers/net/macsec.c +13 -1
index 6d45ba6..5441517 100644
@@ -3206,8 +3206,20 @@ static int macsec_validate_attr(struct nlattr *tb[], struct nlattr *data[])
 	if (data[IFLA_MACSEC_CIPHER_SUITE])
 		csid = nla_get_u64(data[IFLA_MACSEC_CIPHER_SUITE]);
 
-	if (data[IFLA_MACSEC_ICV_LEN])
+	if (data[IFLA_MACSEC_ICV_LEN]) {
 		icv_len = nla_get_u8(data[IFLA_MACSEC_ICV_LEN]);
+		if (icv_len != DEFAULT_ICV_LEN) {
+			char dummy_key[DEFAULT_SAK_LEN] = { 0 };
+			struct crypto_aead *dummy_tfm;
+
+			dummy_tfm = macsec_alloc_tfm(dummy_key,
+						     DEFAULT_SAK_LEN,
+						     icv_len);
+			if (IS_ERR(dummy_tfm))
+				return PTR_ERR(dummy_tfm);
+			crypto_free_aead(dummy_tfm);
+		}
+	}
 
 	switch (csid) {
 	case MACSEC_DEFAULT_CIPHER_ID:
Signature · 1 line
2.5.5
maintainer Acked-by on the v1 series
#4 lore raw
In reply to Davide Caratti
Quoted 9 lines · Davide Caratti

This series provides a fix for macsec configurable ICV length. The maximum length of ICV element has been made compliant to IEEE 802.1AE, and error reporting in case of cipher suite configuration failure has been improved. Finally, a test has been added to netlink verify() callback in order to avoid creation of macsec interfaces having user-provided ICV length values that are not supported by the cipher suite.

Signed-off-by Davide Caratti <[email protected]>
Quoted 8 lines

Davide Caratti (3):
macsec: limit ICV length to 16 octets
macsec: fix error codes when a SA is created
macsec: validate ICV length on link creation

 drivers/net/macsec.c           | 76 ++++++++++++++++++++++++++++--------------
 include/uapi/linux/if_macsec.h |  2 ++
 2 files changed, 53 insertions(+), 25 deletions(-)
Acked-by Sabrina Dubroca <[email protected]>
Signature · 1 line
Sabrina
maintainer
#5 lore raw
In reply to Davide Caratti

From: Davide Caratti <[email protected]>
Date: Fri, 22 Jul 2016 15:07:55 +0200

Quoted 8 lines

This series provides a fix for macsec configurable ICV length. The maximum length of ICV element has been made compliant to IEEE 802.1AE, and error reporting in case of cipher suite configuration failure has been improved. Finally, a test has been added to netlink verify() callback in order to avoid creation of macsec interfaces having user-provided ICV length values that are not supported by the cipher suite.

Signed-off-by Davide Caratti <[email protected]>

Series applied and queued up for -stable, thanks.