[PATCH -stable,4.19.x 04/40] netfilter: nft_set_rbtree: allow loose matching of closing element in interval

[Pablo Neira Ayuso <pablo@netfilter.org>]

commit 3b18d5eba491b2328b31efa4235724a2354af010 upstream.

Allow to find closest matching for the right side of an interval (end
flag set on) so we allow lookups in inner ranges, eg. 10-20 in 5-25.

Fixes: ba0e4d9917b4 ("netfilter: nf_tables: get set elements via netlink")
Reported-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nft_set_rbtree.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c
index 60ef5dea89fa..81b69aa7e35c 100644
--- a/net/netfilter/nft_set_rbtree.c
+++ b/net/netfilter/nft_set_rbtree.c
@@ -145,9 +145,12 @@ static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
 		d = memcmp(this, key, set->klen);
 		if (d < 0) {
 			parent = rcu_dereference_raw(parent->rb_left);
-			interval = rbe;
+			if (!(flags & NFT_SET_ELEM_INTERVAL_END))
+				interval = rbe;
 		} else if (d > 0) {
 			parent = rcu_dereference_raw(parent->rb_right);
+			if (flags & NFT_SET_ELEM_INTERVAL_END)
+				interval = rbe;
 		} else {
 			if (!nft_set_elem_active(&rbe->ext, genmask)) {
 				parent = rcu_dereference_raw(parent->rb_left);
@@ -170,7 +173,10 @@ static bool __nft_rbtree_get(const struct net *net, const struct nft_set *set,
 
 	if (set->flags & NFT_SET_INTERVAL && interval != NULL &&
 	    nft_set_elem_active(&interval->ext, genmask) &&
-	    !nft_rbtree_interval_end(interval)) {
+	    ((!nft_rbtree_interval_end(interval) &&
+	      !(flags & NFT_SET_ELEM_INTERVAL_END)) ||
+	     (nft_rbtree_interval_end(interval) &&
+	      (flags & NFT_SET_ELEM_INTERVAL_END)))) {
 		*elem = interval;
 		return true;
 	}
-- 
2.30.2