set->klen has to be used, not sizeof(). The latter only compares a single register but a full check of the entire key is needed. Example: table ip t { map s { typeof iifname . ip saddr : verdict flags interval } } nft add element t s '{ "lo" . 10.0.0.0/24 : drop }' # no error, expected nft add element t s '{ "lo" . 10.0.0.0/24 : drop }' # no error, expected nft add element t s '{ "lo" . 10.0.0.0/8 : drop }' # bug: no error The 3rd 'add element' should be rejected via -ENOTEMPTY, not -EEXIST, so userspace / nft can report an error to the user. The latter is only correct for the 2nd case (re-add of existing element). As-is, userspace is told that the command was successful, but no elements were added. After this patch, 3rd command gives: Error: Could not process rule: File exists add element t s { "lo" . 127.0.0.0/8 . "lo" : drop } ^^^^^^^^^^^^^^^^^^^^^^^^^ Fixes: 0eb4b5ee33f2 ("netfilter: nft_set_pipapo: Separate partial and complete overlap cases on insertion") Signed-off-by: Florian Westphal --- net/netfilter/nft_set_pipapo.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nft_set_pipapo.c b/net/netfilter/nft_set_pipapo.c index 112fe46788b6..6d77a5f0088a 100644 --- a/net/netfilter/nft_set_pipapo.c +++ b/net/netfilter/nft_set_pipapo.c @@ -1317,8 +1317,8 @@ static int nft_pipapo_insert(const struct net *net, const struct nft_set *set, else dup_end = dup_key; - if (!memcmp(start, dup_key->data, sizeof(*dup_key->data)) && - !memcmp(end, dup_end->data, sizeof(*dup_end->data))) { + if (!memcmp(start, dup_key->data, set->klen) && + !memcmp(end, dup_end->data, set->klen)) { *elem_priv = &dup->priv; return -EEXIST; } -- 2.51.2