Re: [PATCH] netfilter: extend CONFIG_NF_CONNTRACK compile time checks
From: Tom Rix
Date: Tue Jan 11 2022 - 09:20:37 EST
On 1/11/22 1:46 AM, Pablo Neira Ayuso wrote:
Hi,
On Sat, Dec 25, 2021 at 09:37:44AM -0800, trix@xxxxxxxxxx wrote:
From: Tom Rix <trix@xxxxxxxxxx>
Extends
commit 83ace77f5117 ("netfilter: ctnetlink: remove get_ct indirection")
Add some compile time checks by following the ct and ctinfo variables
that are only set when CONFIG_NF_CONNTRACK is enabled.
In nfulnl_log_packet(), ct is only set when CONFIG_NF_CONNTRACK
is enabled. ct's later use in __build_packet_message() is only
meaningful when CONFIG_NF_CONNTRACK is enabled, so add a check.
In nfqnl_build_packet_message(), ct and ctinfo are only set when
CONFIG_NF_CONNTRACK is enabled. Add a check for their decl and use.
nfqnl_ct_parse() is a static function, move the check to the whole
function.
In nfqa_parse_bridge(), ct and ctinfo are only set by the only
call to nfqnl_ct_parse(), so add a check for their decl and use.
Consistently initialize ctinfo to 0.
Are compile warning being trigger without this patch, maybe with
CONFIG_NF_CONNTRACK=n?
No compiler warnings, this was found by visual inspection.
Robot says to entend more, so I want to make sure a human is also
interested.
Tom
Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
---
net/netfilter/nfnetlink_log.c | 4 +++-
net/netfilter/nfnetlink_queue.c | 18 +++++++++++++-----
2 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index ae9c0756bba59..e79d152184b71 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -627,9 +627,11 @@ __build_packet_message(struct nfnl_log_net *log,
htonl(atomic_inc_return(&log->global_seq))))
goto nla_put_failure;
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
if (ct && nfnl_ct->build(inst->skb, ct, ctinfo,
NFULA_CT, NFULA_CT_INFO) < 0)
goto nla_put_failure;
+#endif
if ((pf == NFPROTO_NETDEV || pf == NFPROTO_BRIDGE) &&
nfulnl_put_bridge(inst, skb) < 0)
@@ -689,7 +691,7 @@ nfulnl_log_packet(struct net *net,
struct nfnl_log_net *log = nfnl_log_pernet(net);
const struct nfnl_ct_hook *nfnl_ct = NULL;
struct nf_conn *ct = NULL;
- enum ip_conntrack_info ctinfo;
+ enum ip_conntrack_info ctinfo = 0;
if (li_user && li_user->type == NF_LOG_TYPE_ULOG)
li = li_user;
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 44c3de176d186..d59cae7561bf8 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -386,8 +386,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
struct sk_buff *entskb = entry->skb;
struct net_device *indev;
struct net_device *outdev;
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
struct nf_conn *ct = NULL;
enum ip_conntrack_info ctinfo = 0;
+#endif
struct nfnl_ct_hook *nfnl_ct;
bool csum_verify;
char *secdata = NULL;
@@ -595,8 +597,10 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue,
if (seclen && nla_put(skb, NFQA_SECCTX, seclen, secdata))
goto nla_put_failure;
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
if (ct && nfnl_ct->build(skb, ct, ctinfo, NFQA_CT, NFQA_CT_INFO) < 0)
goto nla_put_failure;
+#endif
if (cap_len > data_len &&
nla_put_be32(skb, NFQA_CAP_LEN, htonl(cap_len)))
@@ -1104,13 +1108,13 @@ static int nfqnl_recv_verdict_batch(struct sk_buff *skb,
return 0;
}
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
static struct nf_conn *nfqnl_ct_parse(struct nfnl_ct_hook *nfnl_ct,
const struct nlmsghdr *nlh,
const struct nlattr * const nfqa[],
struct nf_queue_entry *entry,
enum ip_conntrack_info *ctinfo)
{
-#if IS_ENABLED(CONFIG_NF_CONNTRACK)
struct nf_conn *ct;
ct = nf_ct_get(entry->skb, ctinfo);
@@ -1125,10 +1129,8 @@ static struct nf_conn *nfqnl_ct_parse(struct nfnl_ct_hook *nfnl_ct,
NETLINK_CB(entry->skb).portid,
nlmsg_report(nlh));
return ct;
-#else
- return NULL;
-#endif
}
+#endif
static int nfqa_parse_bridge(struct nf_queue_entry *entry,
const struct nlattr * const nfqa[])
@@ -1172,11 +1174,13 @@ static int nfqnl_recv_verdict(struct sk_buff *skb, const struct nfnl_info *info,
struct nfnl_queue_net *q = nfnl_queue_pernet(info->net);
u_int16_t queue_num = ntohs(info->nfmsg->res_id);
struct nfqnl_msg_verdict_hdr *vhdr;
- enum ip_conntrack_info ctinfo;
struct nfqnl_instance *queue;
struct nf_queue_entry *entry;
struct nfnl_ct_hook *nfnl_ct;
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
struct nf_conn *ct = NULL;
+ enum ip_conntrack_info ctinfo = 0;
+#endif
unsigned int verdict;
int err;
@@ -1198,11 +1202,13 @@ static int nfqnl_recv_verdict(struct sk_buff *skb, const struct nfnl_info *info,
/* rcu lock already held from nfnl->call_rcu. */
nfnl_ct = rcu_dereference(nfnl_ct_hook);
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
if (nfqa[NFQA_CT]) {
if (nfnl_ct != NULL)
ct = nfqnl_ct_parse(nfnl_ct, info->nlh, nfqa, entry,
&ctinfo);
}
+#endif
if (entry->state.pf == PF_BRIDGE) {
err = nfqa_parse_bridge(entry, nfqa);
@@ -1218,8 +1224,10 @@ static int nfqnl_recv_verdict(struct sk_buff *skb, const struct nfnl_info *info,
payload_len, entry, diff) < 0)
verdict = NF_DROP;
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
if (ct && diff)
nfnl_ct->seq_adjust(entry->skb, ct, ctinfo, diff);
+#endif
}
if (nfqa[NFQA_MARK])
--
2.26.3