[PATCH v5 2/2] audit: include source and destination ports to NETFILTER_PKT

Ricardo Robaina
2025-11-06T16:53:31Z

NETFILTER_PKT records show both source and destination
addresses, in addition to the associated networking protocol.
However, it lacks the ports information, which is often
valuable for troubleshooting.

This patch adds both source and destination port numbers,
'sport' and 'dport' respectively, to TCP, UDP, UDP-Lite and
SCTP-related NETFILTER_PKT records.

$ TESTS="netfilter_pkt" make -e test &> /dev/null
$ ausearch -i -ts recent |grep NETFILTER_PKT
type=NETFILTER_PKT ... proto=icmp
type=NETFILTER_PKT ... proto=ipv6-icmp
type=NETFILTER_PKT ... proto=udp sport=46333 dport=42424
type=NETFILTER_PKT ... proto=udp sport=35953 dport=42424
type=NETFILTER_PKT ... proto=tcp sport=50314 dport=42424
type=NETFILTER_PKT ... proto=tcp sport=57346 dport=42424

Link: https://github.com/linux-audit/audit-kernel/issues/162

Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>
---
kernel/audit.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 79 insertions(+), 4 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index 09764003db74..71dcadf12c99 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -60,6 +60,7 @@
#include <net/netns/generic.h>
#include <net/ip.h>
#include <net/ipv6.h>
+#include <linux/sctp.h>

#include "audit.h"

@@ -2544,13 +2545,50 @@ bool audit_log_packet_ip4(struct audit_buffer *ab, struct sk_buff *skb)
{
struct iphdr _iph;
const struct iphdr *ih;
+ struct tcphdr _tcph;
+ const struct tcphdr *th;
+ struct udphdr _udph;
+ const struct udphdr *uh;
+ struct sctphdr _sctph;
+ const struct sctphdr *sh;

ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_iph), &_iph);
if (!ih)
return false;

- audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
- &ih->saddr, &ih->daddr, ih->protocol);
+ switch (ih->protocol) {
+ case IPPROTO_TCP:
+ th = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_tcph), &_tcph);
+ if (!th)
+ return false;
+
+ audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu",
+ &ih->saddr, &ih->daddr, ih->protocol,
+ ntohs(th->source), ntohs(th->dest));
+ break;
+ case IPPROTO_UDP:
+ case IPPROTO_UDPLITE:
+ uh = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_udph), &_udph);
+ if (!uh)
+ return false;
+
+ audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu",
+ &ih->saddr, &ih->daddr, ih->protocol,
+ ntohs(uh->source), ntohs(uh->dest));
+ break;
+ case IPPROTO_SCTP:
+ sh = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_sctph), &_sctph);
+ if (!sh)
+ return false;
+
+ audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu sport=%hu dport=%hu",
+ &ih->saddr, &ih->daddr, ih->protocol,
+ ntohs(sh->source), ntohs(sh->dest));
+ break;
+ default:
+ audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
+ &ih->saddr, &ih->daddr, ih->protocol);
+ }

return true;
}
@@ -2562,6 +2600,12 @@ bool audit_log_packet_ip6(struct audit_buffer *ab, struct sk_buff *skb)
const struct ipv6hdr *ih;
u8 nexthdr;
__be16 frag_off;
+ struct tcphdr _tcph;
+ const struct tcphdr *th;
+ struct udphdr _udph;
+ const struct udphdr *uh;
+ struct sctphdr _sctph;
+ const struct sctphdr *sh;

ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
if (!ih)
@@ -2570,8 +2614,39 @@ bool audit_log_packet_ip6(struct audit_buffer *ab, struct sk_buff *skb)
nexthdr = ih->nexthdr;
ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(_ip6h), &nexthdr, &frag_off);

- audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
- &ih->saddr, &ih->daddr, nexthdr);
+ switch (nexthdr) {
+ case IPPROTO_TCP:
+ th = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_tcph), &_tcph);
+ if (!th)
+ return false;
+
+ audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu",
+ &ih->saddr, &ih->daddr, nexthdr,
+ ntohs(th->source), ntohs(th->dest));
+ break;
+ case IPPROTO_UDP:
+ case IPPROTO_UDPLITE:
+ uh = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_udph), &_udph);
+ if (!uh)
+ return false;
+
+ audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu",
+ &ih->saddr, &ih->daddr, nexthdr,
+ ntohs(uh->source), ntohs(uh->dest));
+ break;
+ case IPPROTO_SCTP:
+ sh = skb_header_pointer(skb, skb_transport_offset(skb), sizeof(_sctph), &_sctph);
+ if (!sh)
+ return false;
+
+ audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu sport=%hu dport=%hu",
+ &ih->saddr, &ih->daddr, nexthdr,
+ ntohs(sh->source), ntohs(sh->dest));
+ break;
+ default:
+ audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
+ &ih->saddr, &ih->daddr, nexthdr);
+ }

return true;
}
--
2.51.1