[PATCH AUTOSEL 6.1 7/9] netfilter: nf_tables: deactivate anonymous set from preparation phase

Sasha Levin
2023-05-11T19:41:45Z

From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit c1592a89942e9678f7d9c8030efa777c0d57edab ]

Toggle deleted anonymous sets as inactive in the next generation, so
users cannot perform any update on it. Clear the generation bitmask
in case the transaction is aborted.

The following KASAN splat shows a set element deletion for a bound
anonymous set that has been already removed in the same transaction.

[ 64.921510] ==================================================================
[ 64.923123] BUG: KASAN: wild-memory-access in nf_tables_commit+0xa24/0x1490 [nf_tables]
[ 64.924745] Write of size 8 at addr dead000000000122 by task test/890
[ 64.927903] CPU: 3 PID: 890 Comm: test Not tainted 6.3.0+ #253
[ 64.931120] Call Trace:
[ 64.932699] <TASK>
[ 64.934292] dump_stack_lvl+0x33/0x50
[ 64.935908] ? nf_tables_commit+0xa24/0x1490 [nf_tables]
[ 64.937551] kasan_report+0xda/0x120
[ 64.939186] ? nf_tables_commit+0xa24/0x1490 [nf_tables]
[ 64.940814] nf_tables_commit+0xa24/0x1490 [nf_tables]
[ 64.942452] ? __kasan_slab_alloc+0x2d/0x60
[ 64.944070] ? nf_tables_setelem_notify+0x190/0x190 [nf_tables]
[ 64.945710] ? kasan_set_track+0x21/0x30
[ 64.947323] nfnetlink_rcv_batch+0x709/0xd90 [nfnetlink]
[ 64.948898] ? nfnetlink_rcv_msg+0x480/0x480 [nfnetlink]

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/net/netfilter/nf_tables.h | 1 +
net/netfilter/nf_tables_api.c | 12 ++++++++++++
net/netfilter/nft_dynset.c | 2 +-
net/netfilter/nft_lookup.c | 2 +-
net/netfilter/nft_objref.c | 2 +-
5 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index 6bacbf57ac175..a1ccf1276f3ee 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -614,6 +614,7 @@ struct nft_set_binding {
};

enum nft_trans_phase;
+void nf_tables_activate_set(const struct nft_ctx *ctx, struct nft_set *set);
void nf_tables_deactivate_set(const struct nft_ctx *ctx, struct nft_set *set,
struct nft_set_binding *binding,
enum nft_trans_phase phase);
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 12d815b9aa131..f82a61d92aa90 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -4936,12 +4936,24 @@ static void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
}
}

+void nf_tables_activate_set(const struct nft_ctx *ctx, struct nft_set *set)
+{
+ if (nft_set_is_anonymous(set))
+ nft_clear(ctx->net, set);
+
+ set->use++;
+}
+EXPORT_SYMBOL_GPL(nf_tables_activate_set);
+
void nf_tables_deactivate_set(const struct nft_ctx *ctx, struct nft_set *set,
struct nft_set_binding *binding,
enum nft_trans_phase phase)
{
switch (phase) {
case NFT_TRANS_PREPARE:
+ if (nft_set_is_anonymous(set))
+ nft_deactivate_next(ctx->net, set);
+
set->use--;
return;
case NFT_TRANS_ABORT:
diff --git a/net/netfilter/nft_dynset.c b/net/netfilter/nft_dynset.c
index 6983e6ddeef90..e65a83328b554 100644
--- a/net/netfilter/nft_dynset.c
+++ b/net/netfilter/nft_dynset.c
@@ -342,7 +342,7 @@ static void nft_dynset_activate(const struct nft_ctx *ctx,
{
struct nft_dynset *priv = nft_expr_priv(expr);

- priv->set->use++;
+ nf_tables_activate_set(ctx, priv->set);
}

static void nft_dynset_destroy(const struct nft_ctx *ctx,
diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c
index d9ad1aa818564..68a5dea805480 100644
--- a/net/netfilter/nft_lookup.c
+++ b/net/netfilter/nft_lookup.c
@@ -167,7 +167,7 @@ static void nft_lookup_activate(const struct nft_ctx *ctx,
{
struct nft_lookup *priv = nft_expr_priv(expr);

- priv->set->use++;
+ nf_tables_activate_set(ctx, priv->set);
}

static void nft_lookup_destroy(const struct nft_ctx *ctx,
diff --git a/net/netfilter/nft_objref.c b/net/netfilter/nft_objref.c
index 5d8d91b3904db..7f8e480b6be5b 100644
--- a/net/netfilter/nft_objref.c
+++ b/net/netfilter/nft_objref.c
@@ -184,7 +184,7 @@ static void nft_objref_map_activate(const struct nft_ctx *ctx,
{
struct nft_objref_map *priv = nft_expr_priv(expr);

- priv->set->use++;
+ nf_tables_activate_set(ctx, priv->set);
}

static void nft_objref_map_destroy(const struct nft_ctx *ctx,
--
2.39.2