[PATCH v5 1/2] audit: add audit_log_packet_ip4 and audit_log_packet_ip6 helper functions

Ricardo Robaina
2025-11-06T16:53:26Z

Netfilter code (net/netfilter/nft_log.c and net/netfilter/xt_AUDIT.c)
have to be kept in sync. Both source files had duplicated versions of
audit_ip4() and audit_ip6() functions, which can result in lack of
consistency and/or duplicated work.

This patch adds two helper functions in audit.c that can be called by
netfilter code commonly, aiming to improve maintainability and
consistency.

Signed-off-by: Ricardo Robaina <rrobaina@redhat.com>
---
include/linux/audit.h | 12 +++++++++++
kernel/audit.c | 39 ++++++++++++++++++++++++++++++++++++
net/netfilter/nft_log.c | 43 ++++------------------------------------
net/netfilter/xt_AUDIT.c | 43 ++++------------------------------------
4 files changed, 59 insertions(+), 78 deletions(-)

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 536f8ee8da81..0f16ced08fdb 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -195,6 +195,8 @@ extern int audit_log_subj_ctx(struct audit_buffer *ab, struct lsm_prop *prop);
extern int audit_log_obj_ctx(struct audit_buffer *ab, struct lsm_prop *prop);
extern int audit_log_task_context(struct audit_buffer *ab);
extern void audit_log_task_info(struct audit_buffer *ab);
+extern bool audit_log_packet_ip4(struct audit_buffer *ab, struct sk_buff *skb);
+extern bool audit_log_packet_ip6(struct audit_buffer *ab, struct sk_buff *skb);

extern int audit_update_lsm_rules(void);

@@ -272,6 +274,16 @@ static inline int audit_log_task_context(struct audit_buffer *ab)
static inline void audit_log_task_info(struct audit_buffer *ab)
{ }

+static inline bool audit_log_packet_ip4(struct audit_buffer *ab, struct sk_buff *skb)
+{
+ return false;
+}
+
+static inline bool audit_log_packet_ip6(struct audit_buffer *ab, struct sk_buff *skb)
+{
+ return false;
+}
+
static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
{
return INVALID_UID;
diff --git a/kernel/audit.c b/kernel/audit.c
index 26a332ffb1b8..09764003db74 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -58,6 +58,8 @@
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
#include <net/netns/generic.h>
+#include <net/ip.h>
+#include <net/ipv6.h>

#include "audit.h"

@@ -2538,6 +2540,43 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
audit_log_end(ab);
}

+bool audit_log_packet_ip4(struct audit_buffer *ab, struct sk_buff *skb)
+{
+ struct iphdr _iph;
+ const struct iphdr *ih;
+
+ 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);
+
+ return true;
+}
+EXPORT_SYMBOL(audit_log_packet_ip4);
+
+bool audit_log_packet_ip6(struct audit_buffer *ab, struct sk_buff *skb)
+{
+ struct ipv6hdr _ip6h;
+ const struct ipv6hdr *ih;
+ u8 nexthdr;
+ __be16 frag_off;
+
+ ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
+ if (!ih)
+ return false;
+
+ 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);
+
+ return true;
+}
+EXPORT_SYMBOL(audit_log_packet_ip6);
+
/**
* audit_set_loginuid - set current task's loginuid
* @loginuid: loginuid value
diff --git a/net/netfilter/nft_log.c b/net/netfilter/nft_log.c
index e35588137995..f53fb4222134 100644
--- a/net/netfilter/nft_log.c
+++ b/net/netfilter/nft_log.c
@@ -26,41 +26,6 @@ struct nft_log {
char *prefix;
};

-static bool audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
-{
- struct iphdr _iph;
- const struct iphdr *ih;
-
- 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);
-
- return true;
-}
-
-static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
-{
- struct ipv6hdr _ip6h;
- const struct ipv6hdr *ih;
- u8 nexthdr;
- __be16 frag_off;
-
- ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
- if (!ih)
- return false;
-
- 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);
-
- return true;
-}
-
static void nft_log_eval_audit(const struct nft_pktinfo *pkt)
{
struct sk_buff *skb = pkt->skb;
@@ -80,18 +45,18 @@ static void nft_log_eval_audit(const struct nft_pktinfo *pkt)
case NFPROTO_BRIDGE:
switch (eth_hdr(skb)->h_proto) {
case htons(ETH_P_IP):
- fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
+ fam = audit_log_packet_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
break;
case htons(ETH_P_IPV6):
- fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
+ fam = audit_log_packet_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
break;
}
break;
case NFPROTO_IPV4:
- fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
+ fam = audit_log_packet_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
break;
case NFPROTO_IPV6:
- fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
+ fam = audit_log_packet_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
break;
}

diff --git a/net/netfilter/xt_AUDIT.c b/net/netfilter/xt_AUDIT.c
index b6a015aee0ce..28cdd6435d56 100644
--- a/net/netfilter/xt_AUDIT.c
+++ b/net/netfilter/xt_AUDIT.c
@@ -28,41 +28,6 @@ MODULE_ALIAS("ip6t_AUDIT");
MODULE_ALIAS("ebt_AUDIT");
MODULE_ALIAS("arpt_AUDIT");

-static bool audit_ip4(struct audit_buffer *ab, struct sk_buff *skb)
-{
- struct iphdr _iph;
- const struct iphdr *ih;
-
- 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);
-
- return true;
-}
-
-static bool audit_ip6(struct audit_buffer *ab, struct sk_buff *skb)
-{
- struct ipv6hdr _ip6h;
- const struct ipv6hdr *ih;
- u8 nexthdr;
- __be16 frag_off;
-
- ih = skb_header_pointer(skb, skb_network_offset(skb), sizeof(_ip6h), &_ip6h);
- if (!ih)
- return false;
-
- 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);
-
- return true;
-}
-
static unsigned int
audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
@@ -81,18 +46,18 @@ audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
case NFPROTO_BRIDGE:
switch (eth_hdr(skb)->h_proto) {
case htons(ETH_P_IP):
- fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
+ fam = audit_log_packet_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
break;
case htons(ETH_P_IPV6):
- fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
+ fam = audit_log_packet_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
break;
}
break;
case NFPROTO_IPV4:
- fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
+ fam = audit_log_packet_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
break;
case NFPROTO_IPV6:
- fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
+ fam = audit_log_packet_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
break;
}

--
2.51.1