From 23cfe941b52e2fa645bdfd770087128a74c7dbee Mon Sep 17 00:00:00 2001 From: Petr Machata Date: Tue, 12 Apr 2022 22:25:06 +0200 Subject: rtnetlink: Fix handling of disabled L3 stats in RTM_GETSTATS replies When L3 stats are disabled, rtnl_offload_xstats_get_size_stats() returns size of 0, which is supposed to be an indication that the corresponding attribute should not be emitted. However, instead, the current code reserves a 0-byte attribute. The reason this does not show up as a citation on a kasan kernel is that netdev_offload_xstats_get(), which is supposed to fill in the data, never ends up getting called, because rtnl_offload_xstats_get_stats() notices that the stats are not actually used and skips the call. Thus a zero-length IFLA_OFFLOAD_XSTATS_L3_STATS attribute ends up in a response, confusing the userspace. Fix by skipping the L3-stats related block in rtnl_offload_xstats_fill(). Fixes: 0e7788fd7622 ("net: rtnetlink: Add UAPI for obtaining L3 offload xstats") Signed-off-by: Petr Machata Reviewed-by: Ido Schimmel Link: https://lore.kernel.org/r/591b58e7623edc3eb66dd1fcfa8c8f133d090974.1649794741.git.petrm@nvidia.com Signed-off-by: Paolo Abeni --- net/core/rtnetlink.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/core/rtnetlink.c') diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 159c9c61e6af..d1381ea6d52e 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -5242,6 +5242,8 @@ static int rtnl_offload_xstats_fill(struct sk_buff *skb, struct net_device *dev, *prividx = attr_id_l3_stats; size_l3 = rtnl_offload_xstats_get_size_stats(dev, t_l3); + if (!size_l3) + goto skip_l3_stats; attr = nla_reserve_64bit(skb, attr_id_l3_stats, size_l3, IFLA_OFFLOAD_XSTATS_UNSPEC); if (!attr) @@ -5253,6 +5255,7 @@ static int rtnl_offload_xstats_fill(struct sk_buff *skb, struct net_device *dev, return err; have_data = true; +skip_l3_stats: *prividx = 0; } -- cgit