From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FE5213A25F; Tue, 9 Jul 2024 11:23:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720524237; cv=none; b=K+p+48dNtfTvip6Fu2h08BT5V1+1owdQwzcfTXuKVxk6EFqnfoORt7NBNlO65S23ZkPS4VFlFxf2ThwML2Ub5WDGgJdeUjksyWA7JiWR7NQCM1Gf/4Kis18FvqUdI2Uq6ccYVpgxAaumzRY4rOxdARFwqN4z50oocJCz3LidbwQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720524237; c=relaxed/simple; bh=fjMSAQ5ZSXKAlHYK1k7AfwQOhHEazQNx4Dt7Tn6Lu6E=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PM1ZNUVMs2bNv7pd8tN1uadgnLx7UTwbd4/4ZtszmIrXh5eRMBD2lL9A1MmIUQir27WXWsRM/Jvdw3y/Hq3QYi2dMq19of54qvn+tccKfmDSaYocRbU9S/CrX/yezUbo99bRoSJGD4hdfSYOV/0Vj+rGevqJxSAn+yRk42/3idQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=v9DV8rI3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="v9DV8rI3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFD89C3277B; Tue, 9 Jul 2024 11:23:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1720524237; bh=fjMSAQ5ZSXKAlHYK1k7AfwQOhHEazQNx4Dt7Tn6Lu6E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=v9DV8rI3HMTLTbWZZs6CakF+bxRVf5UNecf4CfVue8PMtiWjiTJHhr2fUDjjr1T6t 2vid7j6apehkgUiOzgUwWL5e+8c8kbE+++Ti4XC0V9UHPZ9SHnrH6WiSy9nJvb8rTo d6qf6BzFoKg4JHB74UJbyX/Bv8TpHqzq7uMb114M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Florian Westphal , Pablo Neira Ayuso , Sasha Levin , syzbot+4fd66a69358fc15ae2ad@syzkaller.appspotmail.com Subject: [PATCH 6.9 116/197] netfilter: nf_tables: unconditionally flush pending work before notifier Date: Tue, 9 Jul 2024 13:09:30 +0200 Message-ID: <20240709110713.439944902@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240709110708.903245467@linuxfoundation.org> References: <20240709110708.903245467@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Florian Westphal [ Upstream commit 9f6958ba2e902f9820c594869bd710ba74b7c4c0 ] syzbot reports: KASAN: slab-uaf in nft_ctx_update include/net/netfilter/nf_tables.h:1831 KASAN: slab-uaf in nft_commit_release net/netfilter/nf_tables_api.c:9530 KASAN: slab-uaf int nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597 Read of size 2 at addr ffff88802b0051c4 by task kworker/1:1/45 [..] Workqueue: events nf_tables_trans_destroy_work Call Trace: nft_ctx_update include/net/netfilter/nf_tables.h:1831 [inline] nft_commit_release net/netfilter/nf_tables_api.c:9530 [inline] nf_tables_trans_destroy_work+0x152b/0x1750 net/netfilter/nf_tables_api.c:9597 Problem is that the notifier does a conditional flush, but its possible that the table-to-be-removed is still referenced by transactions being processed by the worker, so we need to flush unconditionally. We could make the flush_work depend on whether we found a table to delete in nf-next to avoid the flush for most cases. AFAICS this problem is only exposed in nf-next, with commit e169285f8c56 ("netfilter: nf_tables: do not store nft_ctx in transaction objects"), with this commit applied there is an unconditional fetch of table->family which is whats triggering the above splat. Fixes: 2c9f0293280e ("netfilter: nf_tables: flush pending destroy work before netlink notifier") Reported-and-tested-by: syzbot+4fd66a69358fc15ae2ad@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4fd66a69358fc15ae2ad Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nf_tables_api.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index faa77b031d1f3..0f77ba3306c23 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -11479,8 +11479,7 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event, gc_seq = nft_gc_seq_begin(nft_net); - if (!list_empty(&nf_tables_destroy_list)) - nf_tables_trans_destroy_flush_work(); + nf_tables_trans_destroy_flush_work(); again: list_for_each_entry(table, &nft_net->tables, list) { if (nft_table_has_owner(table) && -- 2.43.0