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netfilter: nf_tables: honor NLM_F_CREATE and NLM_F_EXCL in event noti…
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…fication

Include the NLM_F_CREATE and NLM_F_EXCL flags in netlink event
notifications, otherwise userspace cannot distiguish between create and
add commands.

Fixes: 9651851 ("netfilter: add nftables")
Signed-off-by: Pablo Neira Ayuso <[email protected]>
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@ummakynes
ummakynes committed Oct 2, 2021
1 parent 2c964c5 commit 6fb721c
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Showing 3 changed files with 37 additions and 14 deletions.
2 changes: 1 addition & 1 deletion include/net/netfilter/nf_tables.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1202,7 +1202,7 @@ struct nft_object *nft_obj_lookup(const struct net *net,

void nft_obj_notify(struct net *net, const struct nft_table *table,
struct nft_object *obj, u32 portid, u32 seq,
int event, int family, int report, gfp_t gfp);
int event, u16 flags, int family, int report, gfp_t gfp);

/**
* struct nft_object_type - stateful object type
Expand Down
47 changes: 35 additions & 12 deletions net/netfilter/nf_tables_api.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -780,6 +780,7 @@ static void nf_tables_table_notify(const struct nft_ctx *ctx, int event)
{
struct nftables_pernet *nft_net;
struct sk_buff *skb;
u16 flags = 0;
int err;

if (!ctx->report &&
Expand All @@ -790,8 +791,11 @@ static void nf_tables_table_notify(const struct nft_ctx *ctx, int event)
if (skb == NULL)
goto err;

if (ctx->flags & (NLM_F_CREATE | NLM_F_EXCL))
flags |= ctx->flags & (NLM_F_CREATE | NLM_F_EXCL);

err = nf_tables_fill_table_info(skb, ctx->net, ctx->portid, ctx->seq,
event, 0, ctx->family, ctx->table);
event, flags, ctx->family, ctx->table);
if (err < 0) {
kfree_skb(skb);
goto err;
Expand Down Expand Up @@ -1563,6 +1567,7 @@ static void nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
{
struct nftables_pernet *nft_net;
struct sk_buff *skb;
u16 flags = 0;
int err;

if (!ctx->report &&
Expand All @@ -1573,8 +1578,11 @@ static void nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
if (skb == NULL)
goto err;

if (ctx->flags & (NLM_F_CREATE | NLM_F_EXCL))
flags |= ctx->flags & (NLM_F_CREATE | NLM_F_EXCL);

err = nf_tables_fill_chain_info(skb, ctx->net, ctx->portid, ctx->seq,
event, 0, ctx->family, ctx->table,
event, flags, ctx->family, ctx->table,
ctx->chain);
if (err < 0) {
kfree_skb(skb);
Expand Down Expand Up @@ -2945,6 +2953,8 @@ static void nf_tables_rule_notify(const struct nft_ctx *ctx,
}
if (ctx->flags & (NLM_F_APPEND | NLM_F_REPLACE))
flags |= NLM_F_APPEND;
if (ctx->flags & (NLM_F_CREATE | NLM_F_EXCL))
flags |= ctx->flags & (NLM_F_CREATE | NLM_F_EXCL);

err = nf_tables_fill_rule_info(skb, ctx->net, ctx->portid, ctx->seq,
event, flags, ctx->family, ctx->table,
Expand Down Expand Up @@ -3957,8 +3967,9 @@ static void nf_tables_set_notify(const struct nft_ctx *ctx,
gfp_t gfp_flags)
{
struct nftables_pernet *nft_net = nft_pernet(ctx->net);
struct sk_buff *skb;
u32 portid = ctx->portid;
struct sk_buff *skb;
u16 flags = 0;
int err;

if (!ctx->report &&
Expand All @@ -3969,7 +3980,10 @@ static void nf_tables_set_notify(const struct nft_ctx *ctx,
if (skb == NULL)
goto err;

err = nf_tables_fill_set(skb, ctx, set, event, 0);
if (ctx->flags & (NLM_F_CREATE | NLM_F_EXCL))
flags |= ctx->flags & (NLM_F_CREATE | NLM_F_EXCL);

err = nf_tables_fill_set(skb, ctx, set, event, flags);
if (err < 0) {
kfree_skb(skb);
goto err;
Expand Down Expand Up @@ -5245,12 +5259,13 @@ static int nf_tables_getsetelem(struct sk_buff *skb,
static void nf_tables_setelem_notify(const struct nft_ctx *ctx,
const struct nft_set *set,
const struct nft_set_elem *elem,
int event, u16 flags)
int event)
{
struct nftables_pernet *nft_net;
struct net *net = ctx->net;
u32 portid = ctx->portid;
struct sk_buff *skb;
u16 flags = 0;
int err;

if (!ctx->report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
Expand All @@ -5260,6 +5275,9 @@ static void nf_tables_setelem_notify(const struct nft_ctx *ctx,
if (skb == NULL)
goto err;

if (ctx->flags & (NLM_F_CREATE | NLM_F_EXCL))
flags |= ctx->flags & (NLM_F_CREATE | NLM_F_EXCL);

err = nf_tables_fill_setelem_info(skb, ctx, 0, portid, event, flags,
set, elem);
if (err < 0) {
Expand Down Expand Up @@ -6935,7 +6953,7 @@ static int nf_tables_delobj(struct sk_buff *skb, const struct nfnl_info *info,

void nft_obj_notify(struct net *net, const struct nft_table *table,
struct nft_object *obj, u32 portid, u32 seq, int event,
int family, int report, gfp_t gfp)
u16 flags, int family, int report, gfp_t gfp)
{
struct nftables_pernet *nft_net = nft_pernet(net);
struct sk_buff *skb;
Expand All @@ -6960,8 +6978,9 @@ void nft_obj_notify(struct net *net, const struct nft_table *table,
if (skb == NULL)
goto err;

err = nf_tables_fill_obj_info(skb, net, portid, seq, event, 0, family,
table, obj, false);
err = nf_tables_fill_obj_info(skb, net, portid, seq, event,
flags & (NLM_F_CREATE | NLM_F_EXCL),
family, table, obj, false);
if (err < 0) {
kfree_skb(skb);
goto err;
Expand All @@ -6978,7 +6997,7 @@ static void nf_tables_obj_notify(const struct nft_ctx *ctx,
struct nft_object *obj, int event)
{
nft_obj_notify(ctx->net, ctx->table, obj, ctx->portid, ctx->seq, event,
ctx->family, ctx->report, GFP_KERNEL);
ctx->flags, ctx->family, ctx->report, GFP_KERNEL);
}

/*
Expand Down Expand Up @@ -7759,6 +7778,7 @@ static void nf_tables_flowtable_notify(struct nft_ctx *ctx,
{
struct nftables_pernet *nft_net = nft_pernet(ctx->net);
struct sk_buff *skb;
u16 flags = 0;
int err;

if (!ctx->report &&
Expand All @@ -7769,8 +7789,11 @@ static void nf_tables_flowtable_notify(struct nft_ctx *ctx,
if (skb == NULL)
goto err;

if (ctx->flags & (NLM_F_CREATE | NLM_F_EXCL))
flags |= ctx->flags & (NLM_F_CREATE | NLM_F_EXCL);

err = nf_tables_fill_flowtable_info(skb, ctx->net, ctx->portid,
ctx->seq, event, 0,
ctx->seq, event, flags,
ctx->family, flowtable, hook_list);
if (err < 0) {
kfree_skb(skb);
Expand Down Expand Up @@ -8648,15 +8671,15 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb)
nft_setelem_activate(net, te->set, &te->elem);
nf_tables_setelem_notify(&trans->ctx, te->set,
&te->elem,
NFT_MSG_NEWSETELEM, 0);
NFT_MSG_NEWSETELEM);
nft_trans_destroy(trans);
break;
case NFT_MSG_DELSETELEM:
te = (struct nft_trans_elem *)trans->data;

nf_tables_setelem_notify(&trans->ctx, te->set,
&te->elem,
NFT_MSG_DELSETELEM, 0);
NFT_MSG_DELSETELEM);
nft_setelem_remove(net, te->set, &te->elem);
if (!nft_setelem_is_catchall(te->set, &te->elem)) {
atomic_dec(&te->set->nelems);
Expand Down
2 changes: 1 addition & 1 deletion net/netfilter/nft_quota.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -60,7 +60,7 @@ static void nft_quota_obj_eval(struct nft_object *obj,
if (overquota &&
!test_and_set_bit(NFT_QUOTA_DEPLETED_BIT, &priv->flags))
nft_obj_notify(nft_net(pkt), obj->key.table, obj, 0, 0,
NFT_MSG_NEWOBJ, nft_pf(pkt), 0, GFP_ATOMIC);
NFT_MSG_NEWOBJ, 0, nft_pf(pkt), 0, GFP_ATOMIC);
}

static int nft_quota_do_init(const struct nlattr * const tb[],
Expand Down

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