[PATCH] audit: log nftables configuration change events once per table
Pablo Neira Ayuso
pablo at netfilter.org
Thu Mar 18 16:29:47 UTC 2021
On Thu, Mar 18, 2021 at 11:39:52AM -0400, Richard Guy Briggs wrote:
> 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 at redhat.com>
> ---
> include/linux/audit.h | 29 ++++++++
> net/netfilter/nf_tables_api.c | 132 +++++++++++++---------------------
> 2 files changed, 78 insertions(+), 83 deletions(-)
>
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 82b7c1116a85..bba6a0386742 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -118,6 +118,35 @@ enum audit_nfcfgop {
> AUDIT_NFT_OP_INVALID,
> };
>
> +static const u8 nft2audit_op[] = { // 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,
> + /* NFT_MSG_MAX */ AUDIT_NFT_OP_INVALID,
> +};
> +
> extern int is_audit_feature_set(int which);
>
> extern int __init audit_register_class(int class, unsigned *list);
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index 8d5aa0ac45f4..ad31d8876169 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -709,17 +709,6 @@ 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))
> @@ -1476,18 +1465,6 @@ 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))
> @@ -2838,18 +2815,6 @@ 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))
> @@ -3882,18 +3847,6 @@ 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))
> @@ -5067,18 +5020,6 @@ 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;
> @@ -6278,12 +6219,11 @@ 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,
> @@ -6404,8 +6344,8 @@ 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,
> @@ -6492,15 +6432,15 @@ 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);
>
> @@ -7300,18 +7240,6 @@ 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))
> @@ -7432,9 +7360,6 @@ 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;
> @@ -7979,6 +7904,14 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
> struct nft_trans_elem *te;
> struct nft_chain *chain;
> struct nft_table *table;
> + struct audit_log_nftdata {
> + struct nft_table *table;
> + int entries;
> + int op;
> + struct audit_log_nftdata *next;
Use linux lists instead?
> + } ad = { NULL, 0, 0, NULL }, *adp, *adnext;
> +#define AUNFTABLENAMELEN (NFT_TABLE_MAXNAMELEN + 22)
> + char aubuf[AUNFTABLENAMELEN];
> int err;
>
> if (list_empty(&net->nft.commit_list)) {
> @@ -8173,12 +8106,45 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
> }
> break;
> }
> + adp = &ad;
> + if (!adp->table) {
> + adp->table = trans->ctx.table;
> + adp->entries = 1;
> + adp->op = trans->msg_type;
> + } else {
> + adnext = &ad;
> + do {
> + adp = adnext;
> + if (adp->table == trans->ctx.table)
> + goto found;
> + adnext = adp->next;
> + } while (adnext);
> + adp->next = kzalloc(sizeof(*adp->next), GFP_KERNEL);
> + adp = adp->next;
> + adp->table = trans->ctx.table;
> +found:
> + adp->entries++;
> + if (!adp->op || adp->op > trans->msg_type)
> + adp->op = trans->msg_type;
> + }
Would you wrap this code in a function?
> }
>
> nft_commit_notify(net, NETLINK_CB(skb).portid);
> nf_tables_gen_notify(net, skb, NFT_MSG_NEWGEN);
> nf_tables_commit_release(net);
>
> + adp = &ad;
> + while (adp && adp->table) {
> + snprintf(aubuf, AUNFTABLENAMELEN, "%s:%u", adp->table->name,
> + net->nft.base_seq);
> + audit_log_nfcfg(aubuf, adp->table->family, adp->entries,
> + nft2audit_op[adp->op], GFP_KERNEL);
> + adnext = adp->next;
> + if (adp != &ad)
> + kfree(adp);
> + adp = adnext;
> + }
Same thing here.
Thanks.
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