This patch provides an implementation of the genetlink commands
to associate a given HMAC key identifier with an hashing algorithm
and a secret. It also provides a per-interface sysctl called
seg6_require_hmac, allowing a user-defined policy for processing
HMAC-signed SR-enabled packets. A value of -1 means that the HMAC
field will always be ignored. A value of 0 means that if an HMAC
field is present, its validity will be enforced (the packet is
dropped is the signature is incorrect). Finally, a value of 1 means
that any SR-enabled packet that does not contain an HMAC signature
or whose signature is incorrect will be dropped.
Signed-off-by: David Lebrun <david.leb...@uclouvain.be>
---
include/linux/ipv6.h | 3 +
include/net/seg6.h | 6 ++
include/net/seg6_hmac.h | 1 +
include/uapi/linux/ipv6.h | 1 +
net/ipv6/Makefile | 1 +
net/ipv6/addrconf.c | 18 +++++
net/ipv6/seg6.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++
net/ipv6/seg6_hmac.c | 19 ++++++
8 files changed, 219 insertions(+)
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 76830e6..bad8363 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -65,6 +65,9 @@ struct ipv6_devconf {
__s32 use_oif_addrs_only;
__s32 keep_addr_on_down;
__s32 seg6_enabled;
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ __s32 seg6_require_hmac;
+#endif
struct ctl_table_header *sysctl_header;
};
diff --git a/include/net/seg6.h b/include/net/seg6.h
index 7ff7403..43b7424 100644
--- a/include/net/seg6.h
+++ b/include/net/seg6.h
@@ -17,10 +17,16 @@
#include <linux/net.h>
#include <linux/ipv6.h>
#include <net/lwtunnel.h>
+#ifdef CONFIG_IPV6_SEG6_HMAC
+#include <net/seg6_hmac.h>
+#endif
struct seg6_pernet_data {
struct mutex lock;
struct in6_addr __rcu *tun_src;
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ struct list_head hmac_infos;
+#endif
};
static inline struct seg6_pernet_data *seg6_pernet(struct net *net)
diff --git a/include/net/seg6_hmac.h b/include/net/seg6_hmac.h
index 6e5ee6a..9646b7e 100644
--- a/include/net/seg6_hmac.h
+++ b/include/net/seg6_hmac.h
@@ -21,6 +21,7 @@
#include <linux/ipv6.h>
#include <linux/route.h>
#include <net/seg6.h>
+#include <linux/seg6.h>
#include <linux/seg6_hmac.h>
#define SEG6_HMAC_MAX_DIGESTSIZE 160
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index 7ff1d65..53561be 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -180,6 +180,7 @@ enum {
DEVCONF_KEEP_ADDR_ON_DOWN,
DEVCONF_RTR_SOLICIT_MAX_INTERVAL,
DEVCONF_SEG6_ENABLED,
+ DEVCONF_SEG6_REQUIRE_HMAC,
DEVCONF_MAX
};
diff --git a/net/ipv6/Makefile b/net/ipv6/Makefile
index 59ee92f..129cad2 100644
--- a/net/ipv6/Makefile
+++ b/net/ipv6/Makefile
@@ -44,6 +44,7 @@ obj-$(CONFIG_IPV6_SIT) += sit.o
obj-$(CONFIG_IPV6_TUNNEL) += ip6_tunnel.o
obj-$(CONFIG_IPV6_GRE) += ip6_gre.o
obj-$(CONFIG_IPV6_FOU) += fou6.o
+obj-$(CONFIG_IPV6_SEG6_HMAC) += seg6_hmac.o
obj-y += addrconf_core.o exthdrs_core.o ip6_checksum.o ip6_icmp.o
obj-$(CONFIG_INET) += output_core.o protocol.o $(ipv6-offload)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 8d068ee..6e5f72b 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -240,6 +240,9 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
.ignore_routes_with_linkdown = 0,
.keep_addr_on_down = 0,
.seg6_enabled = 0,
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ .seg6_require_hmac = 0,
+#endif
};
static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -287,6 +290,9 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly
= {
.ignore_routes_with_linkdown = 0,
.keep_addr_on_down = 0,
.seg6_enabled = 0,
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ .seg6_require_hmac = 0,
+#endif
};
/* Check if a valid qdisc is available */
@@ -4968,6 +4974,9 @@ static inline void ipv6_store_devconf(struct ipv6_devconf
*cnf,
array[DEVCONF_DROP_UNSOLICITED_NA] = cnf->drop_unsolicited_na;
array[DEVCONF_KEEP_ADDR_ON_DOWN] = cnf->keep_addr_on_down;
array[DEVCONF_SEG6_ENABLED] = cnf->seg6_enabled;
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ array[DEVCONF_SEG6_REQUIRE_HMAC] = cnf->seg6_require_hmac;
+#endif
}
static inline size_t inet6_ifla6_size(void)
@@ -6066,6 +6075,15 @@ static const struct ctl_table addrconf_sysctl[] = {
.mode = 0644,
.proc_handler = proc_dointvec,
},
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ {
+ .procname = "seg6_require_hmac",
+ .data = &ipv6_devconf.seg6_require_hmac,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+#endif
{
/* sentinel */
}
diff --git a/net/ipv6/seg6.c b/net/ipv6/seg6.c
index fb9ebea..45d9f7e 100644
--- a/net/ipv6/seg6.c
+++ b/net/ipv6/seg6.c
@@ -25,6 +25,9 @@
#include <net/genetlink.h>
#include <linux/seg6.h>
#include <linux/seg6_genl.h>
+#ifdef CONFIG_IPV6_SEG6_HMAC
+#include <net/seg6_hmac.h>
+#endif
static const struct nla_policy seg6_genl_policy[SEG6_ATTR_MAX + 1] = {
[SEG6_ATTR_DST] = { .type = NLA_BINARY,
@@ -46,11 +49,90 @@ static struct genl_family seg6_genl_family = {
.netnsok = true,
};
+#ifdef CONFIG_IPV6_SEG6_HMAC
+
+static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
+{
+ struct net *net = genl_info_net(info);
+ struct seg6_pernet_data *sdata;
+ struct seg6_hmac_info *hinfo;
+ u32 hmackeyid;
+ char *secret;
+ int err = 0;
+ u8 algid;
+ u8 slen;
+
+ sdata = seg6_pernet(net);
+
+ if (!info->attrs[SEG6_ATTR_HMACKEYID] ||
+ !info->attrs[SEG6_ATTR_SECRETLEN] ||
+ !info->attrs[SEG6_ATTR_ALGID])
+ return -EINVAL;
+
+ hmackeyid = nla_get_u32(info->attrs[SEG6_ATTR_HMACKEYID]);
+ slen = nla_get_u8(info->attrs[SEG6_ATTR_SECRETLEN]);
+ algid = nla_get_u8(info->attrs[SEG6_ATTR_ALGID]);
+
+ if (hmackeyid == 0)
+ return -EINVAL;
+
+ if (slen > SEG6_HMAC_SECRET_LEN)
+ return -EINVAL;
+
+ mutex_lock(&sdata->lock);
+ hinfo = seg6_hmac_info_lookup(net, hmackeyid);
+
+ if (!slen) {
+ if (!hinfo || seg6_hmac_info_del(net, hmackeyid, hinfo))
+ err = -ENOENT;
+ else
+ kfree(hinfo);
+
+ goto out_unlock;
+ }
+
+ if (!info->attrs[SEG6_ATTR_SECRET]) {
+ err = -EINVAL;
+ goto out_unlock;
+ }
+
+ if (hinfo) {
+ if (seg6_hmac_info_del(net, hmackeyid, hinfo)) {
+ err = -ENOENT;
+ goto out_unlock;
+ }
+ kfree(hinfo);
+ }
+
+ secret = (char *)nla_data(info->attrs[SEG6_ATTR_SECRET]);
+
+ hinfo = kzalloc(sizeof(*hinfo), GFP_KERNEL);
+ if (!hinfo) {
+ err = -ENOMEM;
+ goto out_unlock;
+ }
+
+ memcpy(hinfo->secret, secret, slen);
+ hinfo->slen = slen;
+ hinfo->alg_id = algid;
+ hinfo->hmackeyid = hmackeyid;
+
+ seg6_hmac_info_add(net, hmackeyid, hinfo);
+
+out_unlock:
+ mutex_unlock(&sdata->lock);
+ return err;
+}
+
+#else
+
static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
{
return -ENOTSUPP;
}
+#endif
+
static int seg6_genl_set_tunsrc(struct sk_buff *skb, struct genl_info *info)
{
struct net *net = genl_info_net(info);
@@ -115,11 +197,78 @@ static int seg6_genl_get_tunsrc(struct sk_buff *skb,
struct genl_info *info)
return -ENOMEM;
}
+#ifdef CONFIG_IPV6_SEG6_HMAC
+
+static int __seg6_hmac_fill_info(struct seg6_hmac_info *hinfo,
+ struct sk_buff *msg)
+{
+ if (nla_put_u32(msg, SEG6_ATTR_HMACKEYID, hinfo->hmackeyid) ||
+ nla_put_u8(msg, SEG6_ATTR_SECRETLEN, hinfo->slen) ||
+ nla_put(msg, SEG6_ATTR_SECRET, hinfo->slen, hinfo->secret) ||
+ nla_put_u8(msg, SEG6_ATTR_ALGID, hinfo->alg_id))
+ return -1;
+
+ return 0;
+}
+
+static int __seg6_genl_dumphmac_element(struct seg6_hmac_info *hinfo,
+ u32 portid, u32 seq, u32 flags,
+ struct sk_buff *skb, u8 cmd)
+{
+ void *hdr;
+
+ hdr = genlmsg_put(skb, portid, seq, &seg6_genl_family, flags, cmd);
+ if (!hdr)
+ return -ENOMEM;
+
+ if (__seg6_hmac_fill_info(hinfo, skb) < 0)
+ goto nla_put_failure;
+
+ genlmsg_end(skb, hdr);
+ return 0;
+
+nla_put_failure:
+ genlmsg_cancel(skb, hdr);
+ return -EMSGSIZE;
+}
+
+static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
+{
+ struct net *net = sock_net(skb->sk);
+ struct seg6_pernet_data *sdata;
+ struct seg6_hmac_info *hinfo;
+ int idx = 0, ret;
+
+ sdata = seg6_pernet(net);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(hinfo, &sdata->hmac_infos, list) {
+ if (idx++ < cb->args[0])
+ continue;
+
+ ret = __seg6_genl_dumphmac_element(hinfo,
+ NETLINK_CB(cb->skb).portid,
+ cb->nlh->nlmsg_seq,
+ NLM_F_MULTI,
+ skb, SEG6_CMD_DUMPHMAC);
+ if (ret)
+ break;
+ }
+ rcu_read_unlock();
+
+ cb->args[0] = idx;
+ return skb->len;
+}
+
+#else
+
static int seg6_genl_dumphmac(struct sk_buff *skb, struct netlink_callback *cb)
{
return -ENOTSUPP;
}
+#endif
+
static const struct genl_ops seg6_genl_ops[] = {
{
.cmd = SEG6_CMD_SETHMAC,
@@ -165,6 +314,10 @@ static int __net_init seg6_net_init(struct net *net)
net->ipv6.seg6_data = sdata;
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ seg6_hmac_net_init(net);
+#endif
+
return 0;
}
@@ -172,6 +325,10 @@ static void __net_exit seg6_net_exit(struct net *net)
{
struct seg6_pernet_data *sdata = seg6_pernet(net);
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ seg6_hmac_net_exit(net);
+#endif
+
kfree(sdata->tun_src);
kfree(sdata);
}
@@ -197,10 +354,20 @@ int __init seg6_init(void)
if (err)
goto out_unregister_pernet;
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ err = seg6_hmac_init();
+ if (err)
+ goto out_unregister_iptun;
+#endif
+
pr_info("Segment Routing with IPv6\n");
out:
return err;
+#ifdef CONFIG_IPV6_SEG6_HMAC
+out_unregister_iptun:
+ seg6_iptunnel_exit();
+#endif
out_unregister_pernet:
unregister_pernet_subsys(&ip6_segments_ops);
out_unregister_genl:
@@ -210,6 +377,9 @@ int __init seg6_init(void)
void seg6_exit(void)
{
+#ifdef CONFIG_IPV6_SEG6_HMAC
+ seg6_hmac_exit();
+#endif
seg6_iptunnel_exit();
unregister_pernet_subsys(&ip6_segments_ops);
genl_unregister_family(&seg6_genl_family);
diff --git a/net/ipv6/seg6_hmac.c b/net/ipv6/seg6_hmac.c
index 96fe950..c09ce36 100644
--- a/net/ipv6/seg6_hmac.c
+++ b/net/ipv6/seg6_hmac.c
@@ -58,6 +58,25 @@ static struct seg6_hmac_algo hmac_algos[] = {
},
};
+static struct sr6_tlv_hmac *seg6_get_tlv_hmac(struct ipv6_sr_hdr *srh)
+{
+ struct sr6_tlv_hmac *tlv;
+
+ if (srh->hdrlen < (srh->first_segment + 1) * 2 + 5)
+ return NULL;
+
+ if (!sr_has_hmac(srh))
+ return NULL;
+
+ tlv = (struct sr6_tlv_hmac *)
+ ((char *)srh + ((srh->hdrlen + 1) << 3) - 40);
+
+ if (tlv->type != SR6_TLV_HMAC || tlv->len != 38)
+ return NULL;
+
+ return tlv;
+}
+
static struct seg6_hmac_algo *__hmac_get_algo(u8 alg_id)
{
struct seg6_hmac_algo *algo;
--
2.7.3
