From: Sven Eckelmann Date: Fri, 29 May 2026 21:36:43 +0000 (+0200) Subject: batman-adv: prevent ELP transmission interval underflow X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5e50d4b8ae3ea622122d3c6a38d7f6fe68dfddca;p=thirdparty%2Flinux.git batman-adv: prevent ELP transmission interval underflow batadv_v_elp_start_timer() enqeues a delayed work. The time when it starts is randomly chosen between (elp_interval - BATADV_JITTER) and (elp_interval + BATADV_JITTER). The configured elp_interval must therefore be larger or equal to BATADV_JITTER to avoid that it causes an underflow of the unsigned integer. If this would happen, then a "fast" ELP interval would turn into a "day long" delay. At the same time, it must not be larger than the maximum value the variable can store. Cc: stable@kernel.org Fixes: a10800829040 ("batman-adv: Add elp_interval hardif genl configuration") Signed-off-by: Sven Eckelmann --- diff --git a/net/batman-adv/netlink.c b/net/batman-adv/netlink.c index e5463003a3bd6..1ba206e402733 100644 --- a/net/batman-adv/netlink.c +++ b/net/batman-adv/netlink.c @@ -919,9 +919,15 @@ static int batadv_netlink_set_hardif(struct sk_buff *skb, #ifdef CONFIG_BATMAN_ADV_BATMAN_V if (info->attrs[BATADV_ATTR_ELP_INTERVAL]) { + u32 elp_interval; + attr = info->attrs[BATADV_ATTR_ELP_INTERVAL]; + elp_interval = nla_get_u32(attr); + + elp_interval = min_t(u32, elp_interval, INT_MAX); + elp_interval = max_t(u32, elp_interval, BATADV_JITTER); - WRITE_ONCE(hard_iface->bat_v.elp_interval, nla_get_u32(attr)); + WRITE_ONCE(hard_iface->bat_v.elp_interval, elp_interval); } if (info->attrs[BATADV_ATTR_THROUGHPUT_OVERRIDE]) {