From d34367991933d28bd7331f67a759be9a8c474014 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 5 Oct 2021 14:04:17 -0700 Subject: [PATCH] rtnetlink: fix if_nlmsg_stats_size() under estimation rtnl_fill_statsinfo() is filling skb with one mandatory if_stats_msg structure. nlmsg_put(skb, pid, seq, type, sizeof(struct if_stats_msg), flags); But if_nlmsg_stats_size() never considered the needed storage. This bug did not show up because alloc_skb(X) allocates skb with extra tailroom, because of added alignments. This could very well be changed in the future to have deterministic behavior. Fixes: 10c9ead9f3c6 ("rtnetlink: add new RTM_GETSTATS message to dump link stats") Signed-off-by: Eric Dumazet Cc: Roopa Prabhu Acked-by: Roopa Prabhu Signed-off-by: David S. Miller --- net/core/rtnetlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 972c8cb303a5..8ccce85562a1 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -5262,7 +5262,7 @@ nla_put_failure: static size_t if_nlmsg_stats_size(const struct net_device *dev, u32 filter_mask) { - size_t size = 0; + size_t size = NLMSG_ALIGN(sizeof(struct if_stats_msg)); if (stats_attr_valid(filter_mask, IFLA_STATS_LINK_64, 0)) size += nla_total_size_64bit(sizeof(struct rtnl_link_stats64)); -- 2.20.1