From: Gao Feng <fgao@xxxxxxxxxx>
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 <fgao@xxxxxxxxxx>
---
v8: Return ERR_PTR(-ENOMEM) instead of NULL;
v7: Remove one debug log and revert to NF_DROP again;
v6: Add one helper function to add synproxy
v5: Return NF_ACCEPT instead of NF_DROP when nfct_seqadj_ext_add failed in nf_nat_setup_info
v4: Drop the packet directly when fail to add seqadj extension;
v3: Remove the warning log when seqadj is null;
v2: Remove the unnessary seqadj check in nf_ct_seq_adjust
v1: Initial patch
include/net/netfilter/nf_conntrack_synproxy.h | 13 +++++++++++++
net/netfilter/nf_conntrack_core.c | 6 +++---
net/netfilter/nf_nat_core.c | 3 ++-
3 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack_synproxy.h b/include/net/netfilter/nf_conntrack_synproxy.h
index 6793614..e8cf825 100644
--- a/include/net/netfilter/nf_conntrack_synproxy.h
+++ b/include/net/netfilter/nf_conntrack_synproxy.h
@@ -27,6 +27,19 @@ 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 dd2c43a..9934b0c 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 de31818..b82282a 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) {
--
1.9.1
--
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