From 4440a2ab3b9f40dddbe006331ef0659c76859296 Mon Sep 17 00:00:00 2001 From: Gao Feng Date: Tue, 13 Sep 2016 08:49:18 +0800 Subject: [PATCH] netfilter: synproxy: Check oom when adding synproxy and seqadj ct extensions When memory is exhausted, nfct_seqadj_ext_add may fail to add the synproxy and seqadj extensions. The function nf_ct_seqadj_init doesn't check if get valid seqadj pointer by the nfct_seqadj. Now drop the packet directly when fail to add seqadj extension to avoid dereference NULL pointer in nf_ct_seqadj_init from init_conntrack(). Signed-off-by: Gao Feng Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_conntrack_synproxy.h | 14 ++++++++++++++ net/netfilter/nf_conntrack_core.c | 6 +++--- net/netfilter/nf_nat_core.c | 3 ++- 3 files changed, 19 insertions(+), 4 deletions(-) diff --git a/include/net/netfilter/nf_conntrack_synproxy.h b/include/net/netfilter/nf_conntrack_synproxy.h index 6793614e6502..e6937318546c 100644 --- a/include/net/netfilter/nf_conntrack_synproxy.h +++ b/include/net/netfilter/nf_conntrack_synproxy.h @@ -27,6 +27,20 @@ static inline struct nf_conn_synproxy *nfct_synproxy_ext_add(struct nf_conn *ct) #endif } +static inline bool nf_ct_add_synproxy(struct nf_conn *ct, + const struct nf_conn *tmpl) +{ + if (tmpl && nfct_synproxy(tmpl)) { + if (!nfct_seqadj_ext_add(ct)) + return false; + + if (!nfct_synproxy_ext_add(ct)) + return false; + } + + return true; +} + struct synproxy_stats { unsigned int syn_received; unsigned int cookie_invalid; diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index dd2c43abf9e2..9934b0c93c1e 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1035,9 +1035,9 @@ init_conntrack(struct net *net, struct nf_conn *tmpl, if (IS_ERR(ct)) return (struct nf_conntrack_tuple_hash *)ct; - if (tmpl && nfct_synproxy(tmpl)) { - nfct_seqadj_ext_add(ct); - nfct_synproxy_ext_add(ct); + if (!nf_ct_add_synproxy(ct, tmpl)) { + nf_conntrack_free(ct); + return ERR_PTR(-ENOMEM); } timeout_ext = tmpl ? nf_ct_timeout_find(tmpl) : NULL; diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index 19c081e1b328..ecee105bbada 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -441,7 +441,8 @@ nf_nat_setup_info(struct nf_conn *ct, ct->status |= IPS_DST_NAT; if (nfct_help(ct)) - nfct_seqadj_ext_add(ct); + if (!nfct_seqadj_ext_add(ct)) + return NF_DROP; } if (maniptype == NF_NAT_MANIP_SRC) { -- 2.20.1