[PATCH -stable,4.14 6/6] netfilter: nf_tables: deactivate anonymous set from preparation phase

Pablo Neira Ayuso
2023-05-11T15:42:15Z

[ backport for 4.14 of 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>
---
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 fe56b2f825b4..2db486e9724c 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -462,6 +462,7 @@ 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 2f5b5d563e4d..c683a45b8ae5 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3420,12 +3420,24 @@ void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set,
}
EXPORT_SYMBOL_GPL(nf_tables_unbind_set);

+void nf_tables_activate_set(const struct nft_ctx *ctx, struct nft_set *set)
+{
+ if (set->flags & NFT_SET_ANONYMOUS)
+ 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 (set->flags & NFT_SET_ANONYMOUS)
+ 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 a20f1668328d..74e8fdaa3432 100644
--- a/net/netfilter/nft_dynset.c
+++ b/net/netfilter/nft_dynset.c
@@ -237,7 +237,7 @@ 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 453f84c57166..4fcbe51e88c7 100644
--- a/net/netfilter/nft_lookup.c
+++ b/net/netfilter/nft_lookup.c
@@ -132,7 +132,7 @@ 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 7e628f4f02b9..49a067a67e72 100644
--- a/net/netfilter/nft_objref.c
+++ b/net/netfilter/nft_objref.c
@@ -168,7 +168,7 @@ 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,
--
2.30.2