Messages in this thread Patch in this message | | | From | Alex Henrie <> | Subject | [PATCH net] net: ipv6/addrconf: clamp temporary address's preferred lifetime to public address's | Date | Fri, 22 Dec 2023 16:42:28 -0700 |
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Fixes: 629df6701c8a ("net: ipv6/addrconf: clamp preferred_lft to the minimum required") Reported-by: Dan Moulding <dan@danm.net> Closes: https://lore.kernel.org/netdev/20231221231115.12402-1-dan@danm.net/ Signed-off-by: Alex Henrie <alexhenrie24@gmail.com> --- net/ipv6/addrconf.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 2692a7b24c40..37141d3417fe 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1337,7 +1337,7 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block) unsigned long tmp_tstamp, age; unsigned long regen_advance; unsigned long now = jiffies; - s32 cnf_temp_preferred_lft; + s32 cnf_temp_preferred_lft, if_public_preferred_lft; struct inet6_ifaddr *ift; struct ifa6_config cfg; long max_desync_factor; @@ -1394,11 +1394,13 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block) } } + 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; @@ -1414,20 +1416,34 @@ static int ipv6_create_tempaddr(struct inet6_ifaddr *ifp, bool block) * particular, an implementation must not create a temporary address * with a zero Preferred Lifetime. * - * Clamp the preferred lifetime to a minimum of regen_advance, unless - * that would exceed valid_lft. + * ... + * + * 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) + if (cfg.preferred_lft <= regen_advance + age) { cfg.preferred_lft = regen_advance + age + 1; - if (cfg.preferred_lft > cfg.valid_lft) { - in6_ifa_put(ifp); - in6_dev_put(idev); - ret = -1; - goto out; + 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; -- 2.43.0
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