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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot+5fcdbfab6d6744c57418@syzkaller.appspotmail.com,
        Pablo Neira Ayuso <pablo@netfilter.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 49/79] netfilter: nf_tables: clean up hook list when offload flags check fails
Date:   Tue, 13 Sep 2022 16:04:54 +0200
Message-Id: <20220913140352.621056306@linuxfoundation.org>
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From: Pablo Neira Ayuso <pablo@netfilter.org>

[ Upstream commit 77972a36ecc4db7fc7c68f0e80714263c5f03f65 ]

splice back the hook list so nft_chain_release_hook() has a chance to
release the hooks.

BUG: memory leak
unreferenced object 0xffff88810180b100 (size 96):
  comm "syz-executor133", pid 3619, jiffies 4294945714 (age 12.690s)
  hex dump (first 32 bytes):
    28 64 23 02 81 88 ff ff 28 64 23 02 81 88 ff ff  (d#.....(d#.....
    90 a8 aa 83 ff ff ff ff 00 00 b5 0f 81 88 ff ff  ................
  backtrace:
    [<ffffffff83a8c59b>] kmalloc include/linux/slab.h:600 [inline]
    [<ffffffff83a8c59b>] nft_netdev_hook_alloc+0x3b/0xc0 net/netfilter/nf_tables_api.c:1901
    [<ffffffff83a9239a>] nft_chain_parse_netdev net/netfilter/nf_tables_api.c:1998 [inline]
    [<ffffffff83a9239a>] nft_chain_parse_hook+0x33a/0x530 net/netfilter/nf_tables_api.c:2073
    [<ffffffff83a9b14b>] nf_tables_addchain.constprop.0+0x10b/0x950 net/netfilter/nf_tables_api.c:2218
    [<ffffffff83a9c41b>] nf_tables_newchain+0xa8b/0xc60 net/netfilter/nf_tables_api.c:2593
    [<ffffffff83a3d6a6>] nfnetlink_rcv_batch+0xa46/0xd20 net/netfilter/nfnetlink.c:517
    [<ffffffff83a3db79>] nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:638 [inline]
    [<ffffffff83a3db79>] nfnetlink_rcv+0x1f9/0x220 net/netfilter/nfnetlink.c:656
    [<ffffffff83a13b17>] netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
    [<ffffffff83a13b17>] netlink_unicast+0x397/0x4c0 net/netlink/af_netlink.c:1345
    [<ffffffff83a13fd6>] netlink_sendmsg+0x396/0x710 net/netlink/af_netlink.c:1921
    [<ffffffff83865ab6>] sock_sendmsg_nosec net/socket.c:714 [inline]
    [<ffffffff83865ab6>] sock_sendmsg+0x56/0x80 net/socket.c:734
    [<ffffffff8386601c>] ____sys_sendmsg+0x36c/0x390 net/socket.c:2482
    [<ffffffff8386a918>] ___sys_sendmsg+0xa8/0x110 net/socket.c:2536
    [<ffffffff8386aaa8>] __sys_sendmsg+0x88/0x100 net/socket.c:2565
    [<ffffffff845e5955>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    [<ffffffff845e5955>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
    [<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: d54725cd11a5 ("netfilter: nf_tables: support for multiple devices per netdev hook")
Reported-by: syzbot+5fcdbfab6d6744c57418@syzkaller.appspotmail.com
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/nf_tables_api.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 1b039476e4d6a..b8e7e1c5c08a8 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -1971,8 +1971,10 @@ static int nft_basechain_init(struct nft_base_chain *basechain, u8 family,
 	chain->flags |= NFT_CHAIN_BASE | flags;
 	basechain->policy = NF_ACCEPT;
 	if (chain->flags & NFT_CHAIN_HW_OFFLOAD &&
-	    !nft_chain_offload_support(basechain))
+	    !nft_chain_offload_support(basechain)) {
+		list_splice_init(&basechain->hook_list, &hook->list);
 		return -EOPNOTSUPP;
+	}
 
 	flow_block_init(&basechain->flow_block);
 
-- 
2.35.1