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Message-ID: <589b485078a65c766bcdee2fd9881c540813f8c5.1763036807.git.rrobaina@redhat.com>
Date: Thu, 13 Nov 2025 10:36:55 -0300
From: Ricardo Robaina <rrobaina@...hat.com>
To: audit@...r.kernel.org,
linux-kernel@...r.kernel.org,
netfilter-devel@...r.kernel.org,
coreteam@...filter.org
Cc: paul@...l-moore.com,
eparis@...hat.com,
fw@...len.de,
pablo@...filter.org,
kadlec@...filter.org,
Ricardo Robaina <rrobaina@...hat.com>
Subject: [PATCH v6 1/2] audit: add audit_log_nf_skb helper function
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 a helper function in audit.c that can be called by
netfilter code commonly, aiming to improve maintainability and
consistency.
Suggested-by: Florian Westphal <fw@...len.de>
Suggested-by: Paul Moore <paul@...l-moore.com>
Signed-off-by: Ricardo Robaina <rrobaina@...hat.com>
---
include/linux/audit.h | 8 +++++
kernel/audit.c | 64 ++++++++++++++++++++++++++++++++++++++++
net/netfilter/nft_log.c | 57 +----------------------------------
net/netfilter/xt_AUDIT.c | 57 +----------------------------------
4 files changed, 74 insertions(+), 112 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 536f8ee8da81..d8173af498ba 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 int audit_log_nf_skb(struct audit_buffer *ab,
+ const struct sk_buff *skb, u8 nfproto);
extern int audit_update_lsm_rules(void);
@@ -272,6 +274,12 @@ static inline int audit_log_task_context(struct audit_buffer *ab)
static inline void audit_log_task_info(struct audit_buffer *ab)
{ }
+static inline int audit_log_nf_skb(struct audit_buffer *ab,
+ const struct sk_buff *skb, u8 nfproto)
+{
+ return 0;
+}
+
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..5c302c4592db 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"
@@ -2488,6 +2490,68 @@ void audit_log_path_denied(int type, const char *operation)
audit_log_end(ab);
}
+int audit_log_nf_skb(struct audit_buffer *ab,
+ const struct sk_buff *skb, u8 nfproto)
+{
+ /* find the IP protocol in the case of NFPROTO_BRIDGE */
+ if (nfproto == NFPROTO_BRIDGE) {
+ switch (eth_hdr(skb)->h_proto) {
+ case htons(ETH_P_IP):
+ nfproto = NFPROTO_IPV4;
+ break;
+ case htons(ETH_P_IPV6):
+ nfproto = NFPROTO_IPV6;
+ break;
+ default:
+ goto unknown_proto;
+ }
+ }
+
+ switch (nfproto) {
+ case NFPROTO_IPV4: {
+ struct iphdr iph;
+ const struct iphdr *ih;
+
+ ih = skb_header_pointer(skb, skb_network_offset(skb),
+ sizeof(iph), &iph);
+ if (!ih)
+ return -ENOMEM;
+
+ audit_log_format(ab, " saddr=%pI4 daddr=%pI4 proto=%hhu",
+ &ih->saddr, &ih->daddr, ih->protocol);
+ break;
+ }
+ case NFPROTO_IPV6: {
+ struct ipv6hdr iph;
+ const struct ipv6hdr *ih;
+ u8 nexthdr;
+ __be16 frag_off;
+
+ ih = skb_header_pointer(skb, skb_network_offset(skb),
+ sizeof(iph), &iph);
+ if (!ih)
+ return -ENOMEM;
+
+ nexthdr = ih->nexthdr;
+ ipv6_skip_exthdr(skb, skb_network_offset(skb) + sizeof(iph),
+ &nexthdr, &frag_off);
+
+ audit_log_format(ab, " saddr=%pI6c daddr=%pI6c proto=%hhu",
+ &ih->saddr, &ih->daddr, nexthdr);
+ break;
+ }
+ default:
+ goto unknown_proto;
+ }
+
+ return 0;
+
+unknown_proto:
+ audit_log_format(ab, " saddr=? daddr=? proto=?");
+ return -EPFNOSUPPORT;
+}
+EXPORT_SYMBOL(audit_log_nf_skb);
+
/* global counter which is incremented every time something logs in */
static atomic_t session_id = ATOMIC_INIT(0);
diff --git a/net/netfilter/nft_log.c b/net/netfilter/nft_log.c
index e35588137995..cd4fc175d9e4 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;
@@ -76,27 +41,7 @@ static void nft_log_eval_audit(const struct nft_pktinfo *pkt)
audit_log_format(ab, "mark=%#x", skb->mark);
- switch (nft_pf(pkt)) {
- case NFPROTO_BRIDGE:
- switch (eth_hdr(skb)->h_proto) {
- case htons(ETH_P_IP):
- fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
- break;
- case htons(ETH_P_IPV6):
- fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
- break;
- }
- break;
- case NFPROTO_IPV4:
- fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
- break;
- case NFPROTO_IPV6:
- fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
- break;
- }
-
- if (fam == -1)
- audit_log_format(ab, " saddr=? daddr=? proto=-1");
+ audit_log_nf_skb(ab, skb, nft_pf(pkt));
audit_log_end(ab);
}
diff --git a/net/netfilter/xt_AUDIT.c b/net/netfilter/xt_AUDIT.c
index b6a015aee0ce..6881a7833707 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)
{
@@ -77,27 +42,7 @@ audit_tg(struct sk_buff *skb, const struct xt_action_param *par)
audit_log_format(ab, "mark=%#x", skb->mark);
- switch (xt_family(par)) {
- case NFPROTO_BRIDGE:
- switch (eth_hdr(skb)->h_proto) {
- case htons(ETH_P_IP):
- fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
- break;
- case htons(ETH_P_IPV6):
- fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
- break;
- }
- break;
- case NFPROTO_IPV4:
- fam = audit_ip4(ab, skb) ? NFPROTO_IPV4 : -1;
- break;
- case NFPROTO_IPV6:
- fam = audit_ip6(ab, skb) ? NFPROTO_IPV6 : -1;
- break;
- }
-
- if (fam == -1)
- audit_log_format(ab, " saddr=? daddr=? proto=-1");
+ audit_log_nf_skb(ab, skb, xt_family(par));
audit_log_end(ab);
--
2.51.1
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