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Message-ID: <20200419121658.GA765@archlinux-current.localdomain>
Date: Sun, 19 Apr 2020 09:16:58 -0300
From: Fernando Gont <fgont@...networks.com>
To: netdev@...r.kernel.org
Cc: David Miller <davem@...emloft.net>
Subject: [PATCH net-next] ipv6: Implement draft-ietf-6man-rfc4941bis
Implement the upcoming rev of RFC4941 (IPv6 temporary addresses):
https://tools.ietf.org/html/draft-ietf-6man-rfc4941bis-09
* Reduces the default Valid Lifetime to 2 days
The number of extra addresses employed when Valid Lifetime was
7 days exacerbated the stress caused on network
elements/devices. Additionally, the motivation for temporary
addresses is indeed privacy and reduced exposure. With a
default Valid Lifetime of 7 days, an address that becomes
revealed by active communication is reachable and exposed for
one whole week. The only use case for a Valid Lifetime of 7
days could be some application that is expecting to have long
lived connections. But if you want to have a long lived
connections, you shouldn't be using a temporary address in the
first place. Additionally, in the era of mobile devices, general
applications should nevertheless be prepared and robust to
address changes (e.g. nodes swap wifi <-> 4G, etc.)
* Employs different IIDs for different prefixes
To avoid network activity correlation among addresses configured
for different prefixes
* Uses a simpler algorithm for IID generation
No need to store "history" anywhere
Signed-off-by: Fernando Gont <fgont@...networks.com>
---
Documentation/networking/ip-sysctl.txt | 2 +-
include/net/addrconf.h | 2 +-
include/net/if_inet6.h | 1 -
net/ipv6/addrconf.c | 85 +++++++++++---------------
4 files changed, 38 insertions(+), 52 deletions(-)
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index 6fcfd313dbe4..e9cf8cf022f7 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1807,7 +1807,7 @@ use_tempaddr - INTEGER
temp_valid_lft - INTEGER
valid lifetime (in seconds) for temporary addresses.
- Default: 604800 (7 days)
+ Default: 172800 (2 days)
temp_prefered_lft - INTEGER
Preferred lifetime (in seconds) for temporary addresses.
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index e0eabe58aa8b..37ecd7d322de 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -8,7 +8,7 @@
#define MIN_VALID_LIFETIME (2*3600) /* 2 hours */
-#define TEMP_VALID_LIFETIME (7*86400)
+#define TEMP_VALID_LIFETIME (2 * 86400)
#define TEMP_PREFERRED_LIFETIME (86400)
#define REGEN_MAX_RETRY (3)
#define MAX_DESYNC_FACTOR (600)
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index a01981d7108f..212eb278bda6 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -190,7 +190,6 @@ struct inet6_dev {
int dead;
u32 desync_factor;
- u8 rndid[8];
struct list_head tempaddr_list;
struct in6_addr token;
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 24e319dfb510..7a0bb5dedcfa 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -135,8 +135,7 @@ static inline void addrconf_sysctl_unregister(struct inet6_dev *idev)
}
#endif
-static void ipv6_regen_rndid(struct inet6_dev *idev);
-static void ipv6_try_regen_rndid(struct inet6_dev *idev, struct in6_addr *tmpaddr);
+static void ipv6_gen_rnd_iid(struct in6_addr *addr);
static int ipv6_generate_eui64(u8 *eui, struct net_device *dev);
static int ipv6_count_addresses(const struct inet6_dev *idev);
@@ -432,8 +431,7 @@ static struct inet6_dev *ipv6_add_dev(struct net_device *dev)
dev->type == ARPHRD_SIT ||
dev->type == ARPHRD_NONE) {
ndev->cnf.use_tempaddr = -1;
- } else
- ipv6_regen_rndid(ndev);
+ }
ndev->token = in6addr_any;
@@ -1306,12 +1304,11 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp)
in6_ifa_put(ifp);
}
-static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp,
- struct inet6_ifaddr *ift,
- bool block)
+static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block)
{
struct inet6_dev *idev = ifp->idev;
- struct in6_addr addr, *tmpaddr;
+ struct in6_addr addr;
+ struct inet6_ifaddr *ift;
unsigned long tmp_tstamp, age;
unsigned long regen_advance;
struct ifa6_config cfg;
@@ -1321,14 +1318,7 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp,
s32 cnf_temp_preferred_lft;
write_lock_bh(&idev->lock);
- if (ift) {
- spin_lock_bh(&ift->lock);
- memcpy(&addr.s6_addr[8], &ift->addr.s6_addr[8], 8);
- spin_unlock_bh(&ift->lock);
- tmpaddr = &addr;
- } else {
- tmpaddr = NULL;
- }
+
retry:
in6_dev_hold(idev);
if (idev->cnf.use_tempaddr <= 0) {
@@ -1351,8 +1341,8 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp,
}
in6_ifa_hold(ifp);
memcpy(addr.s6_addr, ifp->addr.s6_addr, 8);
- ipv6_try_regen_rndid(idev, tmpaddr);
- memcpy(&addr.s6_addr[8], idev->rndid, 8);
+ ipv6_gen_rnd_iid(&addr);
+
age = (now - ifp->tstamp) / HZ;
regen_advance = idev->cnf.regen_max_retry *
@@ -1417,7 +1407,6 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp,
in6_ifa_put(ifp);
in6_dev_put(idev);
pr_info("%s: retry temporary address regeneration\n", __func__);
- tmpaddr = &addr;
write_lock_bh(&idev->lock);
goto retry;
}
@@ -2032,7 +2021,7 @@ static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed)
if (ifpub) {
in6_ifa_hold(ifpub);
spin_unlock_bh(&ifp->lock);
- ipv6_create_tempaddr(ifpub, ifp, true);
+ ipv6_create_tempaddr(ifpub, true);
in6_ifa_put(ifpub);
} else {
spin_unlock_bh(&ifp->lock);
@@ -2329,40 +2318,38 @@ static int ipv6_inherit_eui64(u8 *eui, struct inet6_dev *idev)
return err;
}
-/* (re)generation of randomized interface identifier (RFC 3041 3.2, 3.5) */
-static void ipv6_regen_rndid(struct inet6_dev *idev)
+/* Generation of a randomized Interface Identifier
+ * draft-ietf-6man-rfc4941bis, Section 3.3.1
+ */
+
+static void ipv6_gen_rnd_iid(struct in6_addr *addr)
{
regen:
- get_random_bytes(idev->rndid, sizeof(idev->rndid));
- idev->rndid[0] &= ~0x02;
+ get_random_bytes(&addr->s6_addr[8], 8);
- /*
- * <draft-ietf-ipngwg-temp-addresses-v2-00.txt>:
- * check if generated address is not inappropriate
+ /* <draft-ietf-6man-rfc4941bis-08.txt>, Section 3.3.1:
+ * check if generated address is not inappropriate:
*
- * - Reserved subnet anycast (RFC 2526)
- * 11111101 11....11 1xxxxxxx
- * - ISATAP (RFC4214) 6.1
- * 00-00-5E-FE-xx-xx-xx-xx
- * - value 0
- * - XXX: already assigned to an address on the device
+ * - Reserved IPv6 Interface Identifers
+ * - XXX: already assigned to an address on the device
*/
- if (idev->rndid[0] == 0xfd &&
- (idev->rndid[1]&idev->rndid[2]&idev->rndid[3]&idev->rndid[4]&idev->rndid[5]&idev->rndid[6]) == 0xff &&
- (idev->rndid[7]&0x80))
+
+ /* Subnet-router anycast: 0000:0000:0000:0000 */
+ if (!(addr->s6_addr32[2] | addr->s6_addr32[3]))
goto regen;
- if ((idev->rndid[0]|idev->rndid[1]) == 0) {
- if (idev->rndid[2] == 0x5e && idev->rndid[3] == 0xfe)
- goto regen;
- if ((idev->rndid[2]|idev->rndid[3]|idev->rndid[4]|idev->rndid[5]|idev->rndid[6]|idev->rndid[7]) == 0x00)
- goto regen;
- }
-}
-static void ipv6_try_regen_rndid(struct inet6_dev *idev, struct in6_addr *tmpaddr)
-{
- if (tmpaddr && memcmp(idev->rndid, &tmpaddr->s6_addr[8], 8) == 0)
- ipv6_regen_rndid(idev);
+ /* IANA Ethernet block: 0200:5EFF:FE00:0000-0200:5EFF:FE00:5212
+ * Proxy Mobile IPv6: 0200:5EFF:FE00:5213
+ * IANA Ethernet block: 0200:5EFF:FE00:5214-0200:5EFF:FEFF:FFFF
+ */
+ if (ntohl(addr->s6_addr32[2]) == 0x02005eff &&
+ (ntohl(addr->s6_addr32[3]) & 0Xff000000) == 0xfe000000)
+ goto regen;
+
+ /* Reserved subnet anycast addresses */
+ if (ntohl(addr->s6_addr32[2]) == 0xfdffffff &&
+ ntohl(addr->s6_addr32[3]) >= 0Xffffff80)
+ goto regen;
}
/*
@@ -2544,7 +2531,7 @@ static void manage_tempaddrs(struct inet6_dev *idev,
* no temporary address currently exists.
*/
read_unlock_bh(&idev->lock);
- ipv6_create_tempaddr(ifp, NULL, false);
+ ipv6_create_tempaddr(ifp, false);
} else {
read_unlock_bh(&idev->lock);
}
@@ -4544,7 +4531,7 @@ static void addrconf_verify_rtnl(void)
ifpub->regen_count = 0;
spin_unlock(&ifpub->lock);
rcu_read_unlock_bh();
- ipv6_create_tempaddr(ifpub, ifp, true);
+ ipv6_create_tempaddr(ifpub, true);
in6_ifa_put(ifpub);
in6_ifa_put(ifp);
rcu_read_lock_bh();
--
2.26.0
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