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Message-Id: <e7394a7e66a5ef3186055eb5fbef6d73fbc7edf6.1616641542.git.rgb@redhat.com>
Date: Wed, 24 Mar 2021 23:52:24 -0400
From: Richard Guy Briggs <rgb@...hat.com>
To: Linux-Audit Mailing List <linux-audit@...hat.com>,
LKML <linux-kernel@...r.kernel.org>,
netfilter-devel@...r.kernel.org
Cc: Paul Moore <paul@...l-moore.com>,
Eric Paris <eparis@...isplace.org>,
Steve Grubb <sgrubb@...hat.com>,
Richard Guy Briggs <rgb@...hat.com>,
Florian Westphal <fw@...len.de>, Phil Sutter <phil@....cc>,
twoerner@...hat.com, tgraf@...radead.org, dan.carpenter@...cle.com,
Jones Desougi <jones.desougi+netfilter@...il.com>
Subject: [PATCH v4] audit: log nftables configuration change events once per table
Reduce logging of nftables events to a level similar to iptables.
Restore the table field to list the table, adding the generation.
Indicate the op as the most significant operation in the event.
A couple of sample events:
type=PROCTITLE msg=audit(2021-03-18 09:30:49.801:143) : proctitle=/usr/bin/python3 -s /usr/sbin/firewalld --nofork --nopid
type=SYSCALL msg=audit(2021-03-18 09:30:49.801:143) : arch=x86_64 syscall=sendmsg success=yes exit=172 a0=0x6 a1=0x7ffdcfcbe650 a2=0x0 a3=0x7ffdcfcbd52c items=0 ppid=1 pid=367 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=roo
t sgid=root fsgid=root tty=(none) ses=unset comm=firewalld exe=/usr/bin/python3.9 subj=system_u:system_r:firewalld_t:s0 key=(null)
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.801:143) : table=firewalld:2 family=ipv6 entries=1 op=nft_register_table pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.801:143) : table=firewalld:2 family=ipv4 entries=1 op=nft_register_table pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.801:143) : table=firewalld:2 family=inet entries=1 op=nft_register_table pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=PROCTITLE msg=audit(2021-03-18 09:30:49.839:144) : proctitle=/usr/bin/python3 -s /usr/sbin/firewalld --nofork --nopid
type=SYSCALL msg=audit(2021-03-18 09:30:49.839:144) : arch=x86_64 syscall=sendmsg success=yes exit=22792 a0=0x6 a1=0x7ffdcfcbe650 a2=0x0 a3=0x7ffdcfcbd52c items=0 ppid=1 pid=367 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=r
oot sgid=root fsgid=root tty=(none) ses=unset comm=firewalld exe=/usr/bin/python3.9 subj=system_u:system_r:firewalld_t:s0 key=(null)
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.839:144) : table=firewalld:3 family=ipv6 entries=30 op=nft_register_chain pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.839:144) : table=firewalld:3 family=ipv4 entries=30 op=nft_register_chain pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
type=NETFILTER_CFG msg=audit(2021-03-18 09:30:49.839:144) : table=firewalld:3 family=inet entries=165 op=nft_register_chain pid=367 subj=system_u:system_r:firewalld_t:s0 comm=firewalld
The issue was originally documented in
https://github.com/linux-audit/audit-kernel/issues/124
Signed-off-by: Richard Guy Briggs <rgb@...hat.com>
---
Changelog:
v4:
- move nf_tables_commit_audit_log() before nf_tables_commit_release() [fw]
- move nft2audit_op[] from audit.h to nf_tables_api.c
v3:
- fix function braces, reduce parameter scope [pna]
- pre-allocate nft_audit_data per table in step 1, bail on ENOMEM [pna]
v2:
- convert NFT ops to array indicies in nft2audit_op[] [ps]
- use linux lists [pna]
- use functions for each of collection and logging of audit data [pna]
---
net/netfilter/nf_tables_api.c | 187 +++++++++++++++++++---------------
1 file changed, 104 insertions(+), 83 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index c1eb5cdb3033..9c930fe72005 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -66,6 +66,41 @@ static const struct rhashtable_params nft_objname_ht_params = {
.automatic_shrinking = true,
};
+struct nft_audit_data {
+ struct nft_table *table;
+ int entries;
+ int op;
+ struct list_head list;
+};
+
+static const u8 nft2audit_op[NFT_MSG_MAX] = { // enum nf_tables_msg_types
+ [NFT_MSG_NEWTABLE] = AUDIT_NFT_OP_TABLE_REGISTER,
+ [NFT_MSG_GETTABLE] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_DELTABLE] = AUDIT_NFT_OP_TABLE_UNREGISTER,
+ [NFT_MSG_NEWCHAIN] = AUDIT_NFT_OP_CHAIN_REGISTER,
+ [NFT_MSG_GETCHAIN] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_DELCHAIN] = AUDIT_NFT_OP_CHAIN_UNREGISTER,
+ [NFT_MSG_NEWRULE] = AUDIT_NFT_OP_RULE_REGISTER,
+ [NFT_MSG_GETRULE] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_DELRULE] = AUDIT_NFT_OP_RULE_UNREGISTER,
+ [NFT_MSG_NEWSET] = AUDIT_NFT_OP_SET_REGISTER,
+ [NFT_MSG_GETSET] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_DELSET] = AUDIT_NFT_OP_SET_UNREGISTER,
+ [NFT_MSG_NEWSETELEM] = AUDIT_NFT_OP_SETELEM_REGISTER,
+ [NFT_MSG_GETSETELEM] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_DELSETELEM] = AUDIT_NFT_OP_SETELEM_UNREGISTER,
+ [NFT_MSG_NEWGEN] = AUDIT_NFT_OP_GEN_REGISTER,
+ [NFT_MSG_GETGEN] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_TRACE] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_NEWOBJ] = AUDIT_NFT_OP_OBJ_REGISTER,
+ [NFT_MSG_GETOBJ] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_DELOBJ] = AUDIT_NFT_OP_OBJ_UNREGISTER,
+ [NFT_MSG_GETOBJ_RESET] = AUDIT_NFT_OP_OBJ_RESET,
+ [NFT_MSG_NEWFLOWTABLE] = AUDIT_NFT_OP_FLOWTABLE_REGISTER,
+ [NFT_MSG_GETFLOWTABLE] = AUDIT_NFT_OP_INVALID,
+ [NFT_MSG_DELFLOWTABLE] = AUDIT_NFT_OP_FLOWTABLE_UNREGISTER,
+};
+
static void nft_validate_state_update(struct net *net, u8 new_validate_state)
{
switch (net->nft.validate_state) {
@@ -717,17 +752,6 @@ static void nf_tables_table_notify(const struct nft_ctx *ctx, int event)
{
struct sk_buff *skb;
int err;
- char *buf = kasprintf(GFP_KERNEL, "%s:%llu;?:0",
- ctx->table->name, ctx->table->handle);
-
- audit_log_nfcfg(buf,
- ctx->family,
- ctx->table->use,
- event == NFT_MSG_NEWTABLE ?
- AUDIT_NFT_OP_TABLE_REGISTER :
- AUDIT_NFT_OP_TABLE_UNREGISTER,
- GFP_KERNEL);
- kfree(buf);
if (!ctx->report &&
!nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
@@ -1491,18 +1515,6 @@ static void nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
{
struct sk_buff *skb;
int err;
- char *buf = kasprintf(GFP_KERNEL, "%s:%llu;%s:%llu",
- ctx->table->name, ctx->table->handle,
- ctx->chain->name, ctx->chain->handle);
-
- audit_log_nfcfg(buf,
- ctx->family,
- ctx->chain->use,
- event == NFT_MSG_NEWCHAIN ?
- AUDIT_NFT_OP_CHAIN_REGISTER :
- AUDIT_NFT_OP_CHAIN_UNREGISTER,
- GFP_KERNEL);
- kfree(buf);
if (!ctx->report &&
!nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
@@ -2855,18 +2867,6 @@ static void nf_tables_rule_notify(const struct nft_ctx *ctx,
{
struct sk_buff *skb;
int err;
- char *buf = kasprintf(GFP_KERNEL, "%s:%llu;%s:%llu",
- ctx->table->name, ctx->table->handle,
- ctx->chain->name, ctx->chain->handle);
-
- audit_log_nfcfg(buf,
- ctx->family,
- rule->handle,
- event == NFT_MSG_NEWRULE ?
- AUDIT_NFT_OP_RULE_REGISTER :
- AUDIT_NFT_OP_RULE_UNREGISTER,
- GFP_KERNEL);
- kfree(buf);
if (!ctx->report &&
!nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
@@ -3901,18 +3901,6 @@ static void nf_tables_set_notify(const struct nft_ctx *ctx,
struct sk_buff *skb;
u32 portid = ctx->portid;
int err;
- char *buf = kasprintf(gfp_flags, "%s:%llu;%s:%llu",
- ctx->table->name, ctx->table->handle,
- set->name, set->handle);
-
- audit_log_nfcfg(buf,
- ctx->family,
- set->field_count,
- event == NFT_MSG_NEWSET ?
- AUDIT_NFT_OP_SET_REGISTER :
- AUDIT_NFT_OP_SET_UNREGISTER,
- gfp_flags);
- kfree(buf);
if (!ctx->report &&
!nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
@@ -5097,18 +5085,6 @@ static void nf_tables_setelem_notify(const struct nft_ctx *ctx,
u32 portid = ctx->portid;
struct sk_buff *skb;
int err;
- char *buf = kasprintf(GFP_KERNEL, "%s:%llu;%s:%llu",
- ctx->table->name, ctx->table->handle,
- set->name, set->handle);
-
- audit_log_nfcfg(buf,
- ctx->family,
- set->handle,
- event == NFT_MSG_NEWSETELEM ?
- AUDIT_NFT_OP_SETELEM_REGISTER :
- AUDIT_NFT_OP_SETELEM_UNREGISTER,
- GFP_KERNEL);
- kfree(buf);
if (!ctx->report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
return;
@@ -6310,12 +6286,11 @@ static int nf_tables_dump_obj(struct sk_buff *skb, struct netlink_callback *cb)
filter->type != NFT_OBJECT_UNSPEC &&
obj->ops->type->type != filter->type)
goto cont;
-
if (reset) {
char *buf = kasprintf(GFP_ATOMIC,
- "%s:%llu;?:0",
+ "%s:%u",
table->name,
- table->handle);
+ net->nft.base_seq);
audit_log_nfcfg(buf,
family,
@@ -6436,8 +6411,8 @@ static int nf_tables_getobj(struct net *net, struct sock *nlsk,
reset = true;
if (reset) {
- char *buf = kasprintf(GFP_ATOMIC, "%s:%llu;?:0",
- table->name, table->handle);
+ char *buf = kasprintf(GFP_ATOMIC, "%s:%u",
+ table->name, net->nft.base_seq);
audit_log_nfcfg(buf,
family,
@@ -6525,15 +6500,15 @@ void nft_obj_notify(struct net *net, const struct nft_table *table,
{
struct sk_buff *skb;
int err;
- char *buf = kasprintf(gfp, "%s:%llu;?:0",
- table->name, table->handle);
+ char *buf = kasprintf(gfp, "%s:%u",
+ table->name, net->nft.base_seq);
audit_log_nfcfg(buf,
family,
obj->handle,
event == NFT_MSG_NEWOBJ ?
- AUDIT_NFT_OP_OBJ_REGISTER :
- AUDIT_NFT_OP_OBJ_UNREGISTER,
+ AUDIT_NFT_OP_OBJ_REGISTER :
+ AUDIT_NFT_OP_OBJ_UNREGISTER,
gfp);
kfree(buf);
@@ -7333,18 +7308,6 @@ static void nf_tables_flowtable_notify(struct nft_ctx *ctx,
{
struct sk_buff *skb;
int err;
- char *buf = kasprintf(GFP_KERNEL, "%s:%llu;%s:%llu",
- flowtable->table->name, flowtable->table->handle,
- flowtable->name, flowtable->handle);
-
- audit_log_nfcfg(buf,
- ctx->family,
- flowtable->hooknum,
- event == NFT_MSG_NEWFLOWTABLE ?
- AUDIT_NFT_OP_FLOWTABLE_REGISTER :
- AUDIT_NFT_OP_FLOWTABLE_UNREGISTER,
- GFP_KERNEL);
- kfree(buf);
if (!ctx->report &&
!nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
@@ -7465,9 +7428,6 @@ static void nf_tables_gen_notify(struct net *net, struct sk_buff *skb,
struct sk_buff *skb2;
int err;
- audit_log_nfcfg("?:0;?:0", 0, net->nft.base_seq,
- AUDIT_NFT_OP_GEN_REGISTER, GFP_KERNEL);
-
if (!nlmsg_report(nlh) &&
!nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
return;
@@ -8006,12 +7966,65 @@ static void nft_commit_notify(struct net *net, u32 portid)
WARN_ON_ONCE(!list_empty(&net->nft.notify_list));
}
+int nf_tables_commit_audit_alloc(struct list_head *adl,
+ struct nft_table *table)
+{
+ struct nft_audit_data *adp;
+
+ list_for_each_entry(adp, adl, list) {
+ if (adp->table == table)
+ return 0;
+ }
+ adp = kzalloc(sizeof(*adp), GFP_KERNEL);
+ if (!adp)
+ return -ENOMEM;
+ adp->table = table;
+ INIT_LIST_HEAD(&adp->list);
+ list_add(&adp->list, adl);
+ return 0;
+}
+
+void nf_tables_commit_audit_collect(struct list_head *adl,
+ struct nft_table *table, u32 op)
+{
+ struct nft_audit_data *adp;
+
+ list_for_each_entry(adp, adl, list) {
+ if (adp->table == table)
+ goto found;
+ }
+ WARN_ONCE("table=%s not expected in commit list", table->name);
+ return;
+found:
+ adp->entries++;
+ if (!adp->op || adp->op > op)
+ adp->op = op;
+}
+
+#define AUNFTABLENAMELEN (NFT_TABLE_MAXNAMELEN + 22)
+
+void nf_tables_commit_audit_log(struct list_head *adl, u32 generation)
+{
+ struct nft_audit_data *adp, *adn;
+ char aubuf[AUNFTABLENAMELEN];
+
+ list_for_each_entry_safe(adp, adn, adl, list) {
+ snprintf(aubuf, AUNFTABLENAMELEN, "%s:%u", adp->table->name,
+ generation);
+ audit_log_nfcfg(aubuf, adp->table->family, adp->entries,
+ nft2audit_op[adp->op], GFP_KERNEL);
+ list_del(&adp->list);
+ kfree(adp);
+ }
+}
+
static int nf_tables_commit(struct net *net, struct sk_buff *skb)
{
struct nft_trans *trans, *next;
struct nft_trans_elem *te;
struct nft_chain *chain;
struct nft_table *table;
+ LIST_HEAD(adl);
int err;
if (list_empty(&net->nft.commit_list)) {
@@ -8031,6 +8044,11 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
int ret;
+ ret = nf_tables_commit_audit_alloc(&adl, trans->ctx.table);
+ if (ret) {
+ nf_tables_commit_chain_prepare_cancel(net);
+ return ret;
+ }
if (trans->msg_type == NFT_MSG_NEWRULE ||
trans->msg_type == NFT_MSG_DELRULE) {
chain = trans->ctx.chain;
@@ -8206,10 +8224,13 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
}
break;
}
+ nf_tables_commit_audit_collect(&adl, trans->ctx.table,
+ trans->msg_type);
}
nft_commit_notify(net, NETLINK_CB(skb).portid);
nf_tables_gen_notify(net, skb, NFT_MSG_NEWGEN);
+ nf_tables_commit_audit_log(&adl, net->nft.base_seq);
nf_tables_commit_release(net);
return 0;
--
2.27.0
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