diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 407d917d1a36..bd50df6a5a42 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -2511,7 +2511,7 @@ temp_valid_lft - INTEGER temp_prefered_lft - INTEGER Preferred lifetime (in seconds) for temporary addresses. If temp_prefered_lft is less than the minimum required lifetime (typically - 5-7 seconds), temporary addresses will not be created. If + 5-7 seconds), the preferred lifetime is the minimum required. If temp_prefered_lft is greater than temp_valid_lft, the preferred lifetime is temp_valid_lft. diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 283823fba96a..d3f4b7b9cf1f 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1354,6 +1354,7 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block) unsigned long tmp_tstamp, age; unsigned long regen_advance; unsigned long now = jiffies; + u32 if_public_preferred_lft; s32 cnf_temp_preferred_lft; struct inet6_ifaddr *ift; struct ifa6_config cfg; @@ -1409,11 +1410,13 @@ retry: } } + if_public_preferred_lft = ifp->prefered_lft; + memset(&cfg, 0, sizeof(cfg)); cfg.valid_lft = min_t(__u32, ifp->valid_lft, idev->cnf.temp_valid_lft + age); cfg.preferred_lft = cnf_temp_preferred_lft + age - idev->desync_factor; - cfg.preferred_lft = min_t(__u32, ifp->prefered_lft, cfg.preferred_lft); + cfg.preferred_lft = min_t(__u32, if_public_preferred_lft, cfg.preferred_lft); cfg.preferred_lft = min_t(__u32, cfg.valid_lft, cfg.preferred_lft); cfg.plen = ifp->prefix_len; @@ -1422,19 +1425,41 @@ retry: write_unlock_bh(&idev->lock); - /* A temporary address is created only if this calculated Preferred - * Lifetime is greater than REGEN_ADVANCE time units. In particular, - * an implementation must not create a temporary address with a zero - * Preferred Lifetime. + /* From RFC 4941: + * + * A temporary address is created only if this calculated Preferred + * Lifetime is greater than REGEN_ADVANCE time units. In + * particular, an implementation must not create a temporary address + * with a zero Preferred Lifetime. + * + * ... + * + * When creating a temporary address, the lifetime values MUST be + * derived from the corresponding prefix as follows: + * + * ... + * + * * Its Preferred Lifetime is the lower of the Preferred Lifetime + * of the public address or TEMP_PREFERRED_LIFETIME - + * DESYNC_FACTOR. + * + * To comply with the RFC's requirements, clamp the preferred lifetime + * to a minimum of regen_advance, unless that would exceed valid_lft or + * ifp->prefered_lft. + * * Use age calculation as in addrconf_verify to avoid unnecessary * temporary addresses being generated. */ age = (now - tmp_tstamp + ADDRCONF_TIMER_FUZZ_MINUS) / HZ; if (cfg.preferred_lft <= regen_advance + age) { - in6_ifa_put(ifp); - in6_dev_put(idev); - ret = -1; - goto out; + cfg.preferred_lft = regen_advance + age + 1; + if (cfg.preferred_lft > cfg.valid_lft || + cfg.preferred_lft > if_public_preferred_lft) { + in6_ifa_put(ifp); + in6_dev_put(idev); + ret = -1; + goto out; + } } cfg.ifa_flags = IFA_F_TEMPORARY;