From: Fernando Gont Date: Fri, 1 May 2020 03:51:47 +0000 (-0300) Subject: BACKPORT: ipv6: Implement draft-ietf-6man-rfc4941bis X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3343f72d3f5edcd964a49f5e5de252d230f4fd49;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git BACKPORT: 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 Bug: 175340972 Signed-off-by: Fernando Gont Signed-off-by: David S. Miller (cherry picked from commit 969c54646af0d7d94a5f0f37adbbfe024e85466e) Signed-off-by: Lee Jones Change-Id: Idce8f00b9b29ad329b6b90a5a4a9641c3d2b96d9 --- diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index b648c006b7d2..fb4f2b3bc2b0 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1644,7 +1644,7 @@ 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/if_inet6.h b/include/net/if_inet6.h index d4088d1a688d..c8569e7a9f68 100644 --- a/include/net/if_inet6.h +++ b/include/net/if_inet6.h @@ -193,7 +193,6 @@ 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 c16ea7055f24..59ee7d78db60 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -148,8 +148,7 @@ 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(struct inet6_dev *idev); @@ -449,8 +448,7 @@ 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; @@ -1230,28 +1228,22 @@ out: in6_ifa_put(ifp); } -static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, struct inet6_ifaddr *ift) +static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp) { struct inet6_dev *idev = ifp->idev; - struct in6_addr addr, *tmpaddr; unsigned long tmp_prefered_lft, tmp_valid_lft, tmp_tstamp, age; unsigned long regen_advance; - int tmp_plen; - int ret = 0; - u32 addr_flags; unsigned long now = jiffies; - long max_desync_factor; s32 cnf_temp_preferred_lft; + struct inet6_ifaddr *ift; + long max_desync_factor; + struct in6_addr addr; + int ret = 0; + int tmp_plen; + u32 addr_flags; 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) { @@ -1274,8 +1266,8 @@ retry: } 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 * @@ -1339,7 +1331,6 @@ retry: 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; } @@ -1946,7 +1937,7 @@ 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); + ipv6_create_tempaddr(ifpub); in6_ifa_put(ifpub); } else { spin_unlock_bh(&ifp->lock); @@ -2241,40 +2232,38 @@ 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); - /* - * : - * check if generated address is not inappropriate + /* , 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; } u32 addrconf_rt_table(const struct net_device *dev, u32 default_table) { @@ -2472,7 +2461,7 @@ static void manage_tempaddrs(struct inet6_dev *idev, * no temporary address currently exists. */ read_unlock_bh(&idev->lock); - ipv6_create_tempaddr(ifp, NULL); + ipv6_create_tempaddr(ifp); } else { read_unlock_bh(&idev->lock); } @@ -4404,7 +4393,7 @@ restart: spin_lock(&ifpub->lock); ifpub->regen_count = 0; spin_unlock(&ifpub->lock); - ipv6_create_tempaddr(ifpub, ifp); + ipv6_create_tempaddr(ifpub); in6_ifa_put(ifpub); in6_ifa_put(ifp); goto restart;