From: Florian Westphal <fw@strlen.de>

Date: Tue, 9 Aug 2022 18:34:02 +0200

Subject: netfilter: nf_tables: fix null deref due to zeroed list head

Git-commit: 580077855a40741cf511766129702d97ff02f4d9

Patch-mainline: v6.0-rc1

References: CVE-2023-1095 bsc#1208777

In nf_tables_updtable, if nf_tables_table_enable returns an error,

nft_trans_destroy is called to free the transaction object.

nft_trans_destroy() calls list_del(), but the transaction was never

placed on a list -- the list head is all zeroes, this results in

a null dereference:

BUG: KASAN: null-ptr-deref in nft_trans_destroy+0x26/0x59

Call Trace:

 nft_trans_destroy+0x26/0x59

 nf_tables_newtable+0x4bc/0x9bc

 [..]

Its sane to assume that nft_trans_destroy() can be called

on the transaction object returned by nft_trans_alloc(), so

make sure the list head is initialised.

Fixes: 55dd6f93076b ("netfilter: nf_tables: use new transaction infrastructure to handle table")

Reported-by: mingi cho <mgcho.minic@gmail.com>

Signed-off-by: Florian Westphal <fw@strlen.de>

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Acked-by: Miroslav Franc <mfranc@suse.cz>

---

 net/netfilter/nf_tables_api.c | 1 +

 1 file changed, 1 insertion(+)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c

index 460b0925ea60..3cc88998b879 100644

--- a/net/netfilter/nf_tables_api.c

+++ b/net/netfilter/nf_tables_api.c

@@ -153,6 +153,7 @@ static struct nft_trans *nft_trans_alloc_gfp(const struct nft_ctx *ctx,

 	if (trans == NULL)

 		return NULL;

+	INIT_LIST_HEAD(&trans->list);

 	trans->msg_type = msg_type;

 	trans->ctx	= *ctx;