From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B660C43334 for ; Mon, 13 Jun 2022 10:26:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244189AbiFMK0J (ORCPT ); Mon, 13 Jun 2022 06:26:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45172 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245252AbiFMKY2 (ORCPT ); Mon, 13 Jun 2022 06:24:28 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 88C4823BD5; Mon, 13 Jun 2022 03:18:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0FD8C60AE7; Mon, 13 Jun 2022 10:18:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 15BFAC34114; Mon, 13 Jun 2022 10:18:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655115522; bh=yCAleXJDktB66sB5iU+I8JfPVZVS2tZjE0AbN1XaUk0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aT0rDf/5AlOhTIn1hliLu4aG1GVuuO+emkNjgL810hX/2PZGlq/fQ1upyk574GIjY /2sTkftirwqxpiGr2lkGm0hJIwezKdEid63iubfAER2L4IPJiFdyFhGI+5OafIwmXU vTi34cdWntDZ0KoWC20ECvJbWy7Asntpl4sFwZb8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pablo Neira Ayuso , Ajay Kaher , Aaron Adams Subject: [PATCH 4.9 107/167] netfilter: nf_tables: disallow non-stateful expression in sets earlier Date: Mon, 13 Jun 2022 12:09:41 +0200 Message-Id: <20220613094905.883707696@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094840.720778945@linuxfoundation.org> References: <20220613094840.720778945@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pablo Neira Ayuso commit 520778042ccca019f3ffa136dd0ca565c486cedd upstream. Since 3e135cd499bf ("netfilter: nft_dynset: dynamic stateful expression instantiation"), it is possible to attach stateful expressions to set elements. cd5125d8f518 ("netfilter: nf_tables: split set destruction in deactivate and destroy phase") introduces conditional destruction on the object to accomodate transaction semantics. nft_expr_init() calls expr->ops->init() first, then check for NFT_STATEFUL_EXPR, this stills allows to initialize a non-stateful lookup expressions which points to a set, which might lead to UAF since the set is not properly detached from the set->binding for this case. Anyway, this combination is non-sense from nf_tables perspective. This patch fixes this problem by checking for NFT_STATEFUL_EXPR before expr->ops->init() is called. The reporter provides a KASAN splat and a poc reproducer (similar to those autogenerated by syzbot to report use-after-free errors). It is unknown to me if they are using syzbot or if they use similar automated tool to locate the bug that they are reporting. For the record, this is the KASAN splat. [ 85.431824] ================================================================== [ 85.432901] BUG: KASAN: use-after-free in nf_tables_bind_set+0x81b/0xa20 [ 85.433825] Write of size 8 at addr ffff8880286f0e98 by task poc/776 [ 85.434756] [ 85.434999] CPU: 1 PID: 776 Comm: poc Tainted: G W 5.18.0+ #2 [ 85.436023] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 Fixes: 0b2d8a7b638b ("netfilter: nf_tables: add helper functions for expression handling") Reported-and-tested-by: Aaron Adams Signed-off-by: Pablo Neira Ayuso [Ajay: Regenerated the patch for v4.9.y] Signed-off-by: Ajay Kaher Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nf_tables_api.c | 16 ++++++++++------ net/netfilter/nft_dynset.c | 3 --- 2 files changed, 10 insertions(+), 9 deletions(-) --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1756,23 +1756,27 @@ struct nft_expr *nft_expr_init(const str err = nf_tables_expr_parse(ctx, nla, &info); if (err < 0) - goto err1; + goto err_expr_parse; + + err = -EOPNOTSUPP; + if (!(info.ops->type->flags & NFT_EXPR_STATEFUL)) + goto err_expr_stateful; err = -ENOMEM; expr = kzalloc(info.ops->size, GFP_KERNEL); if (expr == NULL) - goto err2; + goto err_expr_stateful; err = nf_tables_newexpr(ctx, &info, expr); if (err < 0) - goto err3; + goto err_expr_new; return expr; -err3: +err_expr_new: kfree(expr); -err2: +err_expr_stateful: module_put(info.ops->type->owner); -err1: +err_expr_parse: return ERR_PTR(err); } --- a/net/netfilter/nft_dynset.c +++ b/net/netfilter/nft_dynset.c @@ -196,9 +196,6 @@ static int nft_dynset_init(const struct if (IS_ERR(priv->expr)) return PTR_ERR(priv->expr); - err = -EOPNOTSUPP; - if (!(priv->expr->ops->type->flags & NFT_EXPR_STATEFUL)) - goto err1; } else if (set->flags & NFT_SET_EVAL) return -EINVAL;