netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE

ummakynes · gregkh · commit 1adb5c272b20 · 2023-07-27T08:37:27.000+02:00
[ 1240eb9 ] 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 c1592a8 ("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: 958bee1 ("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>
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
@@ -2939,7 +2939,8 @@ static int nf_tables_newrule(struct net *net, struct sock *nlsk,
 
 	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) {
