6.5-stable review patch. If anyone has any objections, please let me know.
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From: Patrick Rohr prohr@google.com
commit 5027d54a9c30bc7ec808360378e2b4753f053f25 upstream.
accept_ra_min_rtr_lft only considered the lifetime of the default route and discarded entire RAs accordingly.
This change renames accept_ra_min_rtr_lft to accept_ra_min_lft, and applies the value to individual RA sections; in particular, router lifetime, PIO preferred lifetime, and RIO lifetime. If any of those lifetimes are lower than the configured value, the specific RA section is ignored.
In order for the sysctl to be useful to Android, it should really apply to all lifetimes in the RA, since that is what determines the minimum frequency at which RAs must be processed by the kernel. Android uses hardware offloads to drop RAs for a fraction of the minimum of all lifetimes present in the RA (some networks have very frequent RAs (5s) with high lifetimes (2h)). Despite this, we have encountered networks that set the router lifetime to 30s which results in very frequent CPU wakeups. Instead of disabling IPv6 (and dropping IPv6 ethertype in the WiFi firmware) entirely on such networks, it seems better to ignore the misconfigured routers while still processing RAs from other IPv6 routers on the same network (i.e. to support IoT applications).
The previous implementation dropped the entire RA based on router lifetime. This turned out to be hard to expand to the other lifetimes present in the RA in a consistent manner; dropping the entire RA based on RIO/PIO lifetimes would essentially require parsing the whole thing twice.
Fixes: 1671bcfd76fd ("net: add sysctl accept_ra_min_rtr_lft") Cc: Lorenzo Colitti lorenzo@google.com Signed-off-by: Patrick Rohr prohr@google.com Reviewed-by: Maciej Żenczykowski maze@google.com Reviewed-by: David Ahern dsahern@kernel.org Link: https://lore.kernel.org/r/20230726230701.919212-1-prohr@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- Documentation/networking/ip-sysctl.rst | 8 ++++---- include/linux/ipv6.h | 2 +- include/uapi/linux/ipv6.h | 2 +- net/ipv6/addrconf.c | 13 ++++++++----- net/ipv6/ndisc.c | 27 +++++++++++---------------- 5 files changed, 25 insertions(+), 27 deletions(-)
--- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -2287,11 +2287,11 @@ accept_ra_min_hop_limit - INTEGER
Default: 1
-accept_ra_min_rtr_lft - INTEGER - Minimum acceptable router lifetime in Router Advertisement. +accept_ra_min_lft - INTEGER + Minimum acceptable lifetime value in Router Advertisement.
- RAs with a router lifetime less than this value shall be - ignored. RAs with a router lifetime of 0 are unaffected. + RA sections with a lifetime less than this value shall be + ignored. Zero lifetimes stay unaffected.
Default: 0
--- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -33,7 +33,7 @@ struct ipv6_devconf { __s32 accept_ra_defrtr; __u32 ra_defrtr_metric; __s32 accept_ra_min_hop_limit; - __s32 accept_ra_min_rtr_lft; + __s32 accept_ra_min_lft; __s32 accept_ra_pinfo; __s32 ignore_routes_with_linkdown; #ifdef CONFIG_IPV6_ROUTER_PREF --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -198,7 +198,7 @@ enum { DEVCONF_IOAM6_ID_WIDE, DEVCONF_NDISC_EVICT_NOCARRIER, DEVCONF_ACCEPT_UNTRACKED_NA, - DEVCONF_ACCEPT_RA_MIN_RTR_LFT, + DEVCONF_ACCEPT_RA_MIN_LFT, DEVCONF_MAX };
--- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -202,7 +202,7 @@ static struct ipv6_devconf ipv6_devconf .ra_defrtr_metric = IP6_RT_PRIO_USER, .accept_ra_from_local = 0, .accept_ra_min_hop_limit= 1, - .accept_ra_min_rtr_lft = 0, + .accept_ra_min_lft = 0, .accept_ra_pinfo = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, @@ -263,7 +263,7 @@ static struct ipv6_devconf ipv6_devconf_ .ra_defrtr_metric = IP6_RT_PRIO_USER, .accept_ra_from_local = 0, .accept_ra_min_hop_limit= 1, - .accept_ra_min_rtr_lft = 0, + .accept_ra_min_lft = 0, .accept_ra_pinfo = 1, #ifdef CONFIG_IPV6_ROUTER_PREF .accept_ra_rtr_pref = 1, @@ -2733,6 +2733,9 @@ void addrconf_prefix_rcv(struct net_devi return; }
+ if (valid_lft != 0 && valid_lft < in6_dev->cnf.accept_ra_min_lft) + return; + /* * Two things going on here: * 1) Add routes for on-link prefixes @@ -5604,7 +5607,7 @@ static inline void ipv6_store_devconf(st array[DEVCONF_IOAM6_ID_WIDE] = cnf->ioam6_id_wide; array[DEVCONF_NDISC_EVICT_NOCARRIER] = cnf->ndisc_evict_nocarrier; array[DEVCONF_ACCEPT_UNTRACKED_NA] = cnf->accept_untracked_na; - array[DEVCONF_ACCEPT_RA_MIN_RTR_LFT] = cnf->accept_ra_min_rtr_lft; + array[DEVCONF_ACCEPT_RA_MIN_LFT] = cnf->accept_ra_min_lft; }
static inline size_t inet6_ifla6_size(void) @@ -6799,8 +6802,8 @@ static const struct ctl_table addrconf_s .proc_handler = proc_dointvec, }, { - .procname = "accept_ra_min_rtr_lft", - .data = &ipv6_devconf.accept_ra_min_rtr_lft, + .procname = "accept_ra_min_lft", + .data = &ipv6_devconf.accept_ra_min_lft, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec, --- a/net/ipv6/ndisc.c +++ b/net/ipv6/ndisc.c @@ -1281,8 +1281,6 @@ static enum skb_drop_reason ndisc_router if (!ndisc_parse_options(skb->dev, opt, optlen, &ndopts)) return SKB_DROP_REASON_IPV6_NDISC_BAD_OPTIONS;
- lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime); - if (!ipv6_accept_ra(in6_dev)) { ND_PRINTK(2, info, "RA: %s, did not accept ra for dev: %s\n", @@ -1290,13 +1288,6 @@ static enum skb_drop_reason ndisc_router goto skip_linkparms; }
- if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_rtr_lft) { - ND_PRINTK(2, info, - "RA: router lifetime (%ds) is too short: %s\n", - lifetime, skb->dev->name); - goto skip_linkparms; - } - #ifdef CONFIG_IPV6_NDISC_NODETYPE /* skip link-specific parameters from interior routers */ if (skb->ndisc_nodetype == NDISC_NODETYPE_NODEFAULT) { @@ -1337,6 +1328,14 @@ static enum skb_drop_reason ndisc_router goto skip_defrtr; }
+ lifetime = ntohs(ra_msg->icmph.icmp6_rt_lifetime); + if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_lft) { + ND_PRINTK(2, info, + "RA: router lifetime (%ds) is too short: %s\n", + lifetime, skb->dev->name); + goto skip_defrtr; + } + /* Do not accept RA with source-addr found on local machine unless * accept_ra_from_local is set to true. */ @@ -1500,13 +1499,6 @@ skip_linkparms: goto out; }
- if (lifetime != 0 && lifetime < in6_dev->cnf.accept_ra_min_rtr_lft) { - ND_PRINTK(2, info, - "RA: router lifetime (%ds) is too short: %s\n", - lifetime, skb->dev->name); - goto out; - } - #ifdef CONFIG_IPV6_ROUTE_INFO if (!in6_dev->cnf.accept_ra_from_local && ipv6_chk_addr(dev_net(in6_dev->dev), &ipv6_hdr(skb)->saddr, @@ -1531,6 +1523,9 @@ skip_linkparms: if (ri->prefix_len == 0 && !in6_dev->cnf.accept_ra_defrtr) continue; + if (ri->lifetime != 0 && + ntohl(ri->lifetime) < in6_dev->cnf.accept_ra_min_lft) + continue; if (ri->prefix_len < in6_dev->cnf.accept_ra_rt_info_min_plen) continue; if (ri->prefix_len > in6_dev->cnf.accept_ra_rt_info_max_plen)