From 2cf55125c64d64cc106e204d53b107094762dfdf Mon Sep 17 00:00:00 2001 From: Oliver Smith Date: Mon, 16 Sep 2013 20:30:57 +0200 Subject: [PATCH] netfilter: ipset: Fix serious failure in CIDR tracking This fixes a serious bug affecting all hash types with a net element - specifically, if a CIDR value is deleted such that none of the same size exist any more, all larger (less-specific) values will then fail to match. Adding back any prefix with a CIDR equal to or more specific than the one deleted will fix it. Steps to reproduce: ipset -N test hash:net ipset -A test 1.1.0.0/16 ipset -A test 2.2.2.0/24 ipset -T test 1.1.1.1 #1.1.1.1 IS in set ipset -D test 2.2.2.0/24 ipset -T test 1.1.1.1 #1.1.1.1 IS NOT in set This is due to the fact that the nets counter was unconditionally decremented prior to the iteration that shifts up the entries. Now, we first check if there is a proceeding entry and if not, decrement it and return. Otherwise, we proceed to iterate and then zero the last element, which, in most cases, will already be zero. Signed-off-by: Oliver Smith Signed-off-by: Jozsef Kadlecsik --- net/netfilter/ipset/ip_set_hash_gen.h | 28 +++++++++++++++------------ 1 file changed, 16 insertions(+), 12 deletions(-) diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h index 57beb1762b2d..707bc520d629 100644 --- a/net/netfilter/ipset/ip_set_hash_gen.h +++ b/net/netfilter/ipset/ip_set_hash_gen.h @@ -325,18 +325,22 @@ mtype_add_cidr(struct htype *h, u8 cidr, u8 nets_length) static void mtype_del_cidr(struct htype *h, u8 cidr, u8 nets_length) { - u8 i, j; - - for (i = 0; i < nets_length - 1 && h->nets[i].cidr != cidr; i++) - ; - h->nets[i].nets--; - - if (h->nets[i].nets != 0) - return; - - for (j = i; j < nets_length - 1 && h->nets[j].nets; j++) { - h->nets[j].cidr = h->nets[j + 1].cidr; - h->nets[j].nets = h->nets[j + 1].nets; + u8 i, j, net_end = nets_length - 1; + + for (i = 0; i < nets_length; i++) { + if (h->nets[i].cidr != cidr) + continue; + if (h->nets[i].nets > 1 || i == net_end || + h->nets[i + 1].nets == 0) { + h->nets[i].nets--; + return; + } + for (j = i; j < net_end && h->nets[j].nets; j++) { + h->nets[j].cidr = h->nets[j + 1].cidr; + h->nets[j].nets = h->nets[j + 1].nets; + } + h->nets[j].nets = 0; + return; } } #endif -- 2.20.1