[PATCH 4.14 087/204] netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE

[PATCH 4.14 087/204] netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE

[Greg Kroah-Hartman]

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

[ 1240eb93f0616b21c675416516ff3d74798fdc97 ]

In case of error when adding a new rule that refers to an anonymous set,
deactivate expressions via NFT_TRANS_PREPARE state, not NFT_TRANS_RELEASE.
Thus, the lookup expression marks anonymous sets as inactive in the next
generation to ensure it is not reachable in this transaction anymore and
decrement the set refcount as introduced by c1592a89942e ("netfilter:
nf_tables: deactivate anonymous set from preparation phase"). The abort
step takes care of undoing the anonymous set.

This is also consistent with rule deletion, where NFT_TRANS_PREPARE is
used. Note that this error path is exercised in the preparation step of
the commit protocol. This patch replaces nf_tables_rule_release() by the
deactivate and destroy calls, this time with NFT_TRANS_PREPARE.

Due to this incorrect error handling, it is possible to access a
dangling pointer to the anonymous set that remains in the transaction
list.

[1009.379054] BUG: KASAN: use-after-free in nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379106] Read of size 8 at addr ffff88816c4c8020 by task nft-rule-add/137110
[1009.379116] CPU: 7 PID: 137110 Comm: nft-rule-add Not tainted 6.4.0-rc4+ #256
[1009.379128] Call Trace:
[1009.379132]  <TASK>
[1009.379135]  dump_stack_lvl+0x33/0x50
[1009.379146]  ? nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379191]  print_address_description.constprop.0+0x27/0x300
[1009.379201]  kasan_report+0x107/0x120
[1009.379210]  ? nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379255]  nft_set_lookup_global+0x147/0x1a0 [nf_tables]
[1009.379302]  nft_lookup_init+0xa5/0x270 [nf_tables]
[1009.379350]  nf_tables_newrule+0x698/0xe50 [nf_tables]
[1009.379397]  ? nf_tables_rule_release+0xe0/0xe0 [nf_tables]
[1009.379441]  ? kasan_unpoison+0x23/0x50
[1009.379450]  nfnetlink_rcv_batch+0x97c/0xd90 [nfnetlink]
[1009.379470]  ? nfnetlink_rcv_msg+0x480/0x480 [nfnetlink]
[1009.379485]  ? __alloc_skb+0xb8/0x1e0
[1009.379493]  ? __alloc_skb+0xb8/0x1e0
[1009.379502]  ? entry_SYSCALL_64_after_hwframe+0x46/0xb0
[1009.379509]  ? unwind_get_return_address+0x2a/0x40
[1009.379517]  ? write_profile+0xc0/0xc0
[1009.379524]  ? avc_lookup+0x8f/0xc0
[1009.379532]  ? __rcu_read_unlock+0x43/0x60

Fixes: 958bee14d071 ("netfilter: nf_tables: use new transaction infrastructure to handle sets")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/netfilter/nf_tables_api.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -2465,7 +2465,8 @@ static int nf_tables_newrule(struct net
 	return 0;
 
 err2:
-	nf_tables_rule_release(&ctx, rule);
+	nft_rule_expr_deactivate(&ctx, rule, NFT_TRANS_PREPARE);
+	nf_tables_rule_destroy(&ctx, rule);
 err1:
 	for (i = 0; i < n; i++) {
 		if (info[i].ops != NULL)

[PATCH 4.14 088/204] netfilter: nf_tables: add NFT_TRANS_PREPARE_ERROR to deal with bound set/chain

[Greg Kroah-Hartman]

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

[ 26b5a5712eb85e253724e56a54c17f8519bd8e4e ]

Add a new state to deal with rule expressions deactivation from the
newrule error path, otherwise the anonymous set remains in the list in
inactive state for the next generation. Mark the set/chain transaction
as unbound so the abort path releases this object, set it as inactive in
the next generation so it is not reachable anymore from this transaction
and reference counter is dropped.

Fixes: 1240eb93f061 ("netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/netfilter/nf_tables.h |    1 +
 net/netfilter/nf_tables_api.c     |   26 ++++++++++++++++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -725,6 +725,7 @@ struct nft_expr_type {
 
 enum nft_trans_phase {
 	NFT_TRANS_PREPARE,
+	NFT_TRANS_PREPARE_ERROR,
 	NFT_TRANS_ABORT,
 	NFT_TRANS_COMMIT,
 	NFT_TRANS_RELEASE
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -140,7 +140,8 @@ static void nft_trans_destroy(struct nft
 	kfree(trans);
 }
 
-static void nft_set_trans_bind(const struct nft_ctx *ctx, struct nft_set *set)
+static void __nft_set_trans_bind(const struct nft_ctx *ctx, struct nft_set *set,
+				 bool bind)
 {
 	struct net *net = ctx->net;
 	struct nft_trans *trans;
@@ -152,16 +153,26 @@ static void nft_set_trans_bind(const str
 		switch (trans->msg_type) {
 		case NFT_MSG_NEWSET:
 			if (nft_trans_set(trans) == set)
-				nft_trans_set_bound(trans) = true;
+				nft_trans_set_bound(trans) = bind;
 			break;
 		case NFT_MSG_NEWSETELEM:
 			if (nft_trans_elem_set(trans) == set)
-				nft_trans_elem_set_bound(trans) = true;
+				nft_trans_elem_set_bound(trans) = bind;
 			break;
 		}
 	}
 }
 
+static void nft_set_trans_bind(const struct nft_ctx *ctx, struct nft_set *set)
+{
+	return __nft_set_trans_bind(ctx, set, true);
+}
+
+static void nft_set_trans_unbind(const struct nft_ctx *ctx, struct nft_set *set)
+{
+	return __nft_set_trans_bind(ctx, set, false);
+}
+
 static int nf_tables_register_hooks(struct net *net,
 				    const struct nft_table *table,
 				    struct nft_chain *chain,
@@ -2465,7 +2476,7 @@ static int nf_tables_newrule(struct net
 	return 0;
 
 err2:
-	nft_rule_expr_deactivate(&ctx, rule, NFT_TRANS_PREPARE);
+	nft_rule_expr_deactivate(&ctx, rule, NFT_TRANS_PREPARE_ERROR);
 	nf_tables_rule_destroy(&ctx, rule);
 err1:
 	for (i = 0; i < n; i++) {
@@ -3446,6 +3457,13 @@ void nf_tables_deactivate_set(const stru
 			      enum nft_trans_phase phase)
 {
 	switch (phase) {
+	case NFT_TRANS_PREPARE_ERROR:
+		nft_set_trans_unbind(ctx, set);
+		if (set->flags & NFT_SET_ANONYMOUS)
+			nft_deactivate_next(ctx->net, set);
+
+		set->use--;
+		break;
 	case NFT_TRANS_PREPARE:
 		if (set->flags & NFT_SET_ANONYMOUS)
 			nft_deactivate_next(ctx->net, set);

[PATCH 4.14 089/204] netfilter: nf_tables: unbind non-anonymous set if rule construction fails

[Greg Kroah-Hartman]

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

[ 3e70489721b6c870252c9082c496703677240f53 ]

Otherwise a dangling reference to a rule object that is gone remains
in the set binding list.

Fixes: 26b5a5712eb8 ("netfilter: nf_tables: add NFT_TRANS_PREPARE_ERROR to deal with bound set/chain")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/netfilter/nf_tables_api.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3461,6 +3461,8 @@ void nf_tables_deactivate_set(const stru
 		nft_set_trans_unbind(ctx, set);
 		if (set->flags & NFT_SET_ANONYMOUS)
 			nft_deactivate_next(ctx->net, set);
+		else
+			list_del_rcu(&binding->list);
 
 		set->use--;
 		break;