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 <[email protected]>
---
Changelog:
v5:
(sorry for all the noise...)
- fix kbuild missing prototype warning in nf_tables_commit_audit_{alloc,collect,log}() <[email protected]>
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..ef51abe3a6d7 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));
}
+static 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;
+}
+
+static 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)
+
+static 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
On Fri, Mar 26, 2021 at 1:39 PM Richard Guy Briggs <[email protected]> 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 <[email protected]>
> ---
> Changelog:
> v5:
> (sorry for all the noise...)
> - fix kbuild missing prototype warning in nf_tables_commit_audit_{alloc,collect,log}() <[email protected]>
>
> 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(-)
Netfilter folks, were you planning to pull this via your tree/netdev
or would you like me to merge this via the audit tree? If the latter,
I would appreciate it if I could get an ACK from one of you; if the
former, my ACK is below.
Acked-by: Paul Moore <[email protected]>
--
paul moore
http://www.paul-moore.com
On Sun, Mar 28, 2021 at 08:50:45PM -0400, Paul Moore wrote:
[...]
> Netfilter folks, were you planning to pull this via your tree/netdev
> or would you like me to merge this via the audit tree? If the latter,
> I would appreciate it if I could get an ACK from one of you; if the
> former, my ACK is below.
>
> Acked-by: Paul Moore <[email protected]>
I'll merge this one into nf-next, this might simplify possible
conflict resolution later on.
Thanks for acking.
On Tue, Mar 30, 2021 at 6:53 PM Pablo Neira Ayuso <[email protected]> wrote:
> On Sun, Mar 28, 2021 at 08:50:45PM -0400, Paul Moore wrote:
> [...]
> > Netfilter folks, were you planning to pull this via your tree/netdev
> > or would you like me to merge this via the audit tree? If the latter,
> > I would appreciate it if I could get an ACK from one of you; if the
> > former, my ACK is below.
> >
> > Acked-by: Paul Moore <[email protected]>
>
> I'll merge this one into nf-next, this might simplify possible
> conflict resolution later on.
Yep, I think that's the best choice. Thanks.
--
paul moore
http://www.paul-moore.com
On Fri, Mar 26, 2021 at 01:38:59PM -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.
There's a UAF, Florian reported. I'm attaching an incremental fix.
nf_tables_commit_audit_collect() refers to the trans object which
might have been already released.
On Fri, Mar 26, 2021 at 01:38:59PM -0400, Richard Guy Briggs wrote:
> @@ -8006,12 +7966,65 @@ static void nft_commit_notify(struct net *net, u32 portid)
> WARN_ON_ONCE(!list_empty(&net->nft.notify_list));
> }
>
> +static 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);
This INIT_LIST_HEAD is not required for an object that is going to be
inserted into the 'adl' list.
> + list_add(&adp->list, adl);
If no objections, I'll amend this patch. I'll include the UAF fix and
remove this unnecessary INIT_LIST_HEAD.
On 2021-03-31 22:22, Pablo Neira Ayuso wrote:
> On Fri, Mar 26, 2021 at 01:38:59PM -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.
>
> There's a UAF, Florian reported. I'm attaching an incremental fix.
>
> nf_tables_commit_audit_collect() refers to the trans object which
> might have been already released.
Got it. Thanks Pablo. I didn't see it when running nft-test.py Where
was it reported? Here I tried to stay out of the way by putting that
call at the end of the loop but that was obviously a mistake in
hindsight. :-)
> commit e4d272948d25b66d86fc241cefd95281bfb1079e
> Author: Pablo Neira Ayuso <[email protected]>
> Date: Wed Mar 31 22:19:51 2021 +0200
>
> netfilter: nf_tables: use-after-free
>
> Signed-off-by: Pablo Neira Ayuso <[email protected]>
>
> diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
> index 5dd4bb7cabf5..01674c0d9103 100644
> --- a/net/netfilter/nf_tables_api.c
> +++ b/net/netfilter/nf_tables_api.c
> @@ -8063,6 +8063,8 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
> net->nft.gencursor = nft_gencursor_next(net);
>
> list_for_each_entry_safe(trans, next, &net->nft.commit_list, list) {
> + nf_tables_commit_audit_collect(&adl, trans->ctx.table,
> + trans->msg_type);
> switch (trans->msg_type) {
> case NFT_MSG_NEWTABLE:
> if (nft_trans_table_update(trans)) {
> @@ -8211,8 +8213,6 @@ 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);
- RGB
--
Richard Guy Briggs <[email protected]>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
On Wed, Mar 31, 2021 at 04:53:10PM -0400, Richard Guy Briggs wrote:
> On 2021-03-31 22:22, Pablo Neira Ayuso wrote:
> > On Fri, Mar 26, 2021 at 01:38:59PM -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.
> >
> > There's a UAF, Florian reported. I'm attaching an incremental fix.
> >
> > nf_tables_commit_audit_collect() refers to the trans object which
> > might have been already released.
>
> Got it. Thanks Pablo. I didn't see it when running nft-test.py Where
> was it reported?
CONFIG_KASAN.
> Here I tried to stay out of the way by putting that
> call at the end of the loop but that was obviously a mistake in
> hindsight. :-)
No problem, I'll squash this incremental fix into your audit patch.
On 2021-03-31 22:46, Pablo Neira Ayuso wrote:
> On Fri, Mar 26, 2021 at 01:38:59PM -0400, Richard Guy Briggs wrote:
> > @@ -8006,12 +7966,65 @@ static void nft_commit_notify(struct net *net, u32 portid)
> > WARN_ON_ONCE(!list_empty(&net->nft.notify_list));
> > }
> >
> > +static 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);
>
> This INIT_LIST_HEAD is not required for an object that is going to be
> inserted into the 'adl' list.
>
> > + list_add(&adp->list, adl);
>
> If no objections, I'll amend this patch. I'll include the UAF fix and
> remove this unnecessary INIT_LIST_HEAD.
Ok, so it is harmless other than being code noise and overhead, thanks again.
- RGB
--
Richard Guy Briggs <[email protected]>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
On 2021-04-01 15:24, Phil Sutter wrote:
> On Fri, Mar 26, 2021 at 01:38:59PM -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 <[email protected]>
>
> Tested this patch to make sure it eliminates the slowdown of
> iptables-nft when auditd is running. With this applied, neither
> iptables-nft-restore nor 'iptables-nft -F' show a significant
> difference in run-time between running or stopped auditd, at least for
> large rulesets. Individual calls suffer from added audit logging, but
> that's expected of course.
>
> Tested-by: Phil Sutter <[email protected]>
Excellent, thanks Phil for helping nail this one down and confirming the
fix.
> Thanks, Phil
- RGB
--
Richard Guy Briggs <[email protected]>
Sr. S/W Engineer, Kernel Security, Base Operating Systems
Remote, Ottawa, Red Hat Canada
IRC: rgb, SunRaycer
Voice: +1.647.777.2635, Internal: (81) 32635
On Fri, Mar 26, 2021 at 01:38:59PM -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 <[email protected]>
Tested this patch to make sure it eliminates the slowdown of
iptables-nft when auditd is running. With this applied, neither
iptables-nft-restore nor 'iptables-nft -F' show a significant
difference in run-time between running or stopped auditd, at least for
large rulesets. Individual calls suffer from added audit logging, but
that's expected of course.
Tested-by: Phil Sutter <[email protected]>
Thanks, Phil