Re: [PATCH ghak124 v3] audit: log nftables configuration change events

On Thursday, June 4, 2020 9:20:49 AM EDT Richard Guy Briggs wrote: > iptables, ip6tables, arptables and ebtables table registration, > replacement and unregistration configuration events are logged for the > native (legacy) iptables setsockopt api, but not for the > nftables netlink api which is used by the nft-variant of iptables in > addition to nftables itself. > > Add calls to log the configuration actions in the nftables netlink api. > > This uses the same NETFILTER_CFG record format but overloads the table > field. > > type=NETFILTER_CFG msg=audit(2020-05-28 17:46:41.878:162) : table=?:0;?:0 > family=unspecified entries=2 op=nft_register_gen pid=396 > subj=system_u:system_r:firewalld_t:s0 comm=firewalld ... > type=NETFILTER_CFG msg=audit(2020-05-28 17:46:41.878:162) : > table=firewalld:1;?:0 family=inet entries=0 op=nft_register_table pid=396 > subj=system_u:system_r:firewalld_t:s0 comm=firewalld ... > type=NETFILTER_CFG msg=audit(2020-05-28 17:46:41.911:163) : > table=firewalld:1;filter_FORWARD:85 family=inet entries=8 > op=nft_register_chain pid=396 subj=system_u:system_r:firewalld_t:s0 > comm=firewalld ... > type=NETFILTER_CFG msg=audit(2020-05-28 17:46:41.911:163) : > table=firewalld:1;filter_FORWARD:85 family=inet entries=101 > op=nft_register_rule pid=396 subj=system_u:system_r:firewalld_t:s0 > comm=firewalld ... > type=NETFILTER_CFG msg=audit(2020-05-28 17:46:41.911:163) : > table=firewalld:1;__set0:87 family=inet entries=87 op=nft_register_setelem > pid=396 subj=system_u:system_r:firewalld_t:s0 comm=firewalld ... > type=NETFILTER_CFG msg=audit(2020-05-28 17:46:41.911:163) : > table=firewalld:1;__set0:87 family=inet entries=0 op=nft_register_set > pid=396 subj=system_u:system_r:firewalld_t:s0 comm=firewalld > > For further information please see issue > https://github.com/linux-audit/audit-kernel/issues/124 > > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > --- > Changelog: > v3: > - inline message type rather than table > > v2: > - differentiate between xtables and nftables > - add set, setelem, obj, flowtable, gen > - use nentries field as appropriate per type > - overload the "tables" field with table handle and chain/set/flowtable > > include/linux/audit.h | 18 ++++++++ > kernel/auditsc.c | 24 ++++++++-- > net/netfilter/nf_tables_api.c | 103 > ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 142 > insertions(+), 3 deletions(-) > > diff --git a/include/linux/audit.h b/include/linux/audit.h > index 3fcd9ee49734..604ede630580 100644 > --- a/include/linux/audit.h > +++ b/include/linux/audit.h > @@ -12,6 +12,7 @@ > #include <linux/sched.h> > #include <linux/ptrace.h> > #include <uapi/linux/audit.h> > +#include <uapi/linux/netfilter/nf_tables.h> > > #define AUDIT_INO_UNSET ((unsigned long)-1) > #define AUDIT_DEV_UNSET ((dev_t)-1) > @@ -98,6 +99,23 @@ enum audit_nfcfgop { > AUDIT_XT_OP_REGISTER, > AUDIT_XT_OP_REPLACE, > AUDIT_XT_OP_UNREGISTER, > + AUDIT_NFT_OP_TABLE_REGISTER, > + AUDIT_NFT_OP_TABLE_UNREGISTER, > + AUDIT_NFT_OP_CHAIN_REGISTER, > + AUDIT_NFT_OP_CHAIN_UNREGISTER, > + AUDIT_NFT_OP_RULE_REGISTER, > + AUDIT_NFT_OP_RULE_UNREGISTER, > + AUDIT_NFT_OP_SET_REGISTER, > + AUDIT_NFT_OP_SET_UNREGISTER, > + AUDIT_NFT_OP_SETELEM_REGISTER, > + AUDIT_NFT_OP_SETELEM_UNREGISTER, > + AUDIT_NFT_OP_GEN_REGISTER, > + AUDIT_NFT_OP_OBJ_REGISTER, > + AUDIT_NFT_OP_OBJ_UNREGISTER, > + AUDIT_NFT_OP_OBJ_RESET, > + AUDIT_NFT_OP_FLOWTABLE_REGISTER, > + AUDIT_NFT_OP_FLOWTABLE_UNREGISTER, > + AUDIT_NFT_OP_INVALID, > }; > > extern int is_audit_feature_set(int which); > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index 468a23390457..3a9100e95fda 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -75,6 +75,7 @@ > #include <linux/uaccess.h> > #include <linux/fsnotify_backend.h> > #include <uapi/linux/limits.h> > +#include <uapi/linux/netfilter/nf_tables.h> > > #include "audit.h" > > @@ -136,9 +137,26 @@ struct audit_nfcfgop_tab { > }; > > static const struct audit_nfcfgop_tab audit_nfcfgs[] = { > - { AUDIT_XT_OP_REGISTER, "register" }, > - { AUDIT_XT_OP_REPLACE, "replace" }, > - { AUDIT_XT_OP_UNREGISTER, "unregister" }, > + { AUDIT_XT_OP_REGISTER, "xt_register" }, > + { AUDIT_XT_OP_REPLACE, "xt_replace" }, > + { AUDIT_XT_OP_UNREGISTER, "xt_unregister" }, > + { AUDIT_NFT_OP_TABLE_REGISTER, "nft_register_table" }, > + { AUDIT_NFT_OP_TABLE_UNREGISTER, "nft_unregister_table" }, > + { AUDIT_NFT_OP_CHAIN_REGISTER, "nft_register_chain" }, > + { AUDIT_NFT_OP_CHAIN_UNREGISTER, "nft_unregister_chain" }, > + { AUDIT_NFT_OP_RULE_REGISTER, "nft_register_rule" }, > + { AUDIT_NFT_OP_RULE_UNREGISTER, "nft_unregister_rule" }, > + { AUDIT_NFT_OP_SET_REGISTER, "nft_register_set" }, > + { AUDIT_NFT_OP_SET_UNREGISTER, "nft_unregister_set" }, > + { AUDIT_NFT_OP_SETELEM_REGISTER, "nft_register_setelem" }, > + { AUDIT_NFT_OP_SETELEM_UNREGISTER, "nft_unregister_setelem" }, > + { AUDIT_NFT_OP_GEN_REGISTER, "nft_register_gen" }, > + { AUDIT_NFT_OP_OBJ_REGISTER, "nft_register_obj" }, > + { AUDIT_NFT_OP_OBJ_UNREGISTER, "nft_unregister_obj" }, > + { AUDIT_NFT_OP_OBJ_RESET, "nft_reset_obj" }, > + { AUDIT_NFT_OP_FLOWTABLE_REGISTER, "nft_register_flowtable" }, > + { AUDIT_NFT_OP_FLOWTABLE_UNREGISTER, "nft_unregister_flowtable" }, > + { AUDIT_NFT_OP_INVALID, "nft_invalid" }, > }; I still don't like the event format because it doesn't give complete subject information. However, I thought I'd comment on this string table. Usually it's sufficient to log the number and then have the string table in user space which looks it up during interpretation.

-Steve > static int audit_match_perm(struct audit_context *ctx, int mask) > diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c > index 3558e76e2733..b9e7440cc87d 100644 > --- a/net/netfilter/nf_tables_api.c > +++ b/net/netfilter/nf_tables_api.c > @@ -12,6 +12,7 @@ > #include <linux/netlink.h> > #include <linux/vmalloc.h> > #include <linux/rhashtable.h> > +#include <linux/audit.h> > #include <linux/netfilter.h> > #include <linux/netfilter/nfnetlink.h> > #include <linux/netfilter/nf_tables.h> > @@ -693,6 +694,16 @@ 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); > + kfree(buf); > > if (!ctx->report && > !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES)) > @@ -1428,6 +1439,17 @@ 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); > + kfree(buf); > > if (!ctx->report && > !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES)) > @@ -2691,6 +2713,17 @@ 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); > + kfree(buf); > > if (!ctx->report && > !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES)) > @@ -3693,6 +3726,17 @@ 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); > + kfree(buf); > > if (!ctx->report && > !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES)) > @@ -4809,6 +4853,17 @@ 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); > + kfree(buf); > > if (!ctx->report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES)) > return; > @@ -5890,6 +5945,19 @@ static int nf_tables_dump_obj(struct sk_buff *skb, > struct netlink_callback *cb) obj->ops->type->type != filter->type) > goto cont; > > + if (reset) { > + char *buf = kasprintf(GFP_KERNEL, > + "%s:%llu;?:0", > + table->name, > + table->handle); > + > + audit_log_nfcfg(buf, > + family, > + obj->handle, > + AUDIT_NFT_OP_OBJ_RESET); > + kfree(buf); > + } > + > if (nf_tables_fill_obj_info(skb, net, NETLINK_CB(cb- >skb).portid, > cb->nlh->nlmsg_seq, > NFT_MSG_NEWOBJ, > @@ -6000,6 +6068,17 @@ static int nf_tables_getobj(struct net *net, struct > sock *nlsk, if (NFNL_MSG_TYPE(nlh->nlmsg_type) == NFT_MSG_GETOBJ_RESET) > reset = true; > > + if (reset) { > + char *buf = kasprintf(GFP_KERNEL, "%s:%llu;?:0", > + table->name, table->handle); > + > + audit_log_nfcfg(buf, > + family, > + obj->handle, > + AUDIT_NFT_OP_OBJ_RESET); > + kfree(buf); > + } > + > err = nf_tables_fill_obj_info(skb2, net, NETLINK_CB(skb).portid, > nlh->nlmsg_seq, NFT_MSG_NEWOBJ, 0, > family, table, obj, reset); > @@ -6075,6 +6154,16 @@ void nft_obj_notify(struct net *net, const struct > nft_table *table, { > struct sk_buff *skb; > int err; > + char *buf = kasprintf(GFP_KERNEL, "%s:%llu;?:0", > + table->name, table->handle); > + > + audit_log_nfcfg(buf, > + family, > + obj->handle, > + event == NFT_MSG_NEWOBJ ? > + AUDIT_NFT_OP_OBJ_REGISTER : > + AUDIT_NFT_OP_OBJ_UNREGISTER); > + kfree(buf); > > if (!report && > !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES)) > @@ -6701,6 +6790,17 @@ 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); > + kfree(buf); > > if (ctx->report && > !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES)) > @@ -6822,6 +6922,9 @@ 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); > + > if (nlmsg_report(nlh) && > !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES)) > return;