[PATCH AUTOSEL 5.4 2/2] netfilter: nf_tables: deactivate anonymous set from preparation phase

[Sasha Levin <sashal@kernel.org>]

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 886866bee8b27..ad2a52a6c478b 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -493,6 +493,7 @@ 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 140c24f1b6c60..f60d130c15676 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3909,12 +3909,24 @@ 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 6bcc18124e5bd..7f9e6c90f7271 100644
--- a/net/netfilter/nft_dynset.c
+++ b/net/netfilter/nft_dynset.c
@@ -259,7 +259,7 @@ 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 660bad688e2bc..4eb4d076927e4 100644
--- a/net/netfilter/nft_lookup.c
+++ b/net/netfilter/nft_lookup.c
@@ -129,7 +129,7 @@ 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 bfd18d2b65a28..74c61278e6bd3 100644
--- a/net/netfilter/nft_objref.c
+++ b/net/netfilter/nft_objref.c
@@ -180,7 +180,7 @@ 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