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 DB5F48F57 for ; Sun, 16 Jul 2023 20:52:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5B19AC433C8; Sun, 16 Jul 2023 20:52:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689540739; bh=3PgARpoWSwEpNQz1h07/Ra0r2oN1jwiPWQOElYi2O1Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dNzA0dGHZQYICTqYxs8cjyvH4ChGZlKRPRYKOaafU9y59CrKcLBwsUPC7KkwiBq3b dUpLd/TdTzoCn6CNofq6QzSKqH47gfPfsaekHWbyf9C4LglOlTVNShOhevu1dXQy/5 Z0UBFb6ytEPSikB3qOu7zRnZsI7ppFmkdeMjTO4s= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Florian Westphal , Simon Horman , Jamal Hadi Salim , Paolo Abeni , Sasha Levin Subject: [PATCH 6.1 471/591] net/sched: act_ipt: add sanity checks on table name and hook locations Date: Sun, 16 Jul 2023 21:50:10 +0200 Message-ID: <20230716194936.092319534@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230716194923.861634455@linuxfoundation.org> References: <20230716194923.861634455@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Florian Westphal [ Upstream commit b4ee93380b3c891fea996af8d1d3ca0e36ad31f0 ] Looks like "tc" hard-codes "mangle" as the only supported table name, but on kernel side there are no checks. This is wrong. Not all xtables targets are safe to call from tc. E.g. "nat" targets assume skb has a conntrack object assigned to it. Normally those get called from netfilter nat core which consults the nat table to obtain the address mapping. "tc" userspace either sets PRE or POSTROUTING as hook number, but there is no validation of this on kernel side, so update netlink policy to reject bogus numbers. Some targets may assume skb_dst is set for input/forward hooks, so prevent those from being used. act_ipt uses the hook number in two places: 1. the state hook number, this is fine as-is 2. to set par.hook_mask The latter is a bit mask, so update the assignment to make xt_check_target() to the right thing. Followup patch adds required checks for the skb/packet headers before calling the targets evaluation function. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Florian Westphal Reviewed-by: Simon Horman Acked-by: Jamal Hadi Salim Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/sched/act_ipt.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c index 1625e10374161..dc92975a9374f 100644 --- a/net/sched/act_ipt.c +++ b/net/sched/act_ipt.c @@ -47,7 +47,7 @@ static int ipt_init_target(struct net *net, struct xt_entry_target *t, par.entryinfo = &e; par.target = target; par.targinfo = t->data; - par.hook_mask = hook; + par.hook_mask = 1 << hook; par.family = NFPROTO_IPV4; ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); @@ -84,7 +84,8 @@ static void tcf_ipt_release(struct tc_action *a) static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, - [TCA_IPT_HOOK] = { .type = NLA_U32 }, + [TCA_IPT_HOOK] = NLA_POLICY_RANGE(NLA_U32, NF_INET_PRE_ROUTING, + NF_INET_NUMHOOKS), [TCA_IPT_INDEX] = { .type = NLA_U32 }, [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) }, }; @@ -157,15 +158,27 @@ static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla, return -EEXIST; } } + + err = -EINVAL; hook = nla_get_u32(tb[TCA_IPT_HOOK]); + switch (hook) { + case NF_INET_PRE_ROUTING: + break; + case NF_INET_POST_ROUTING: + break; + default: + goto err1; + } + + if (tb[TCA_IPT_TABLE]) { + /* mangle only for now */ + if (nla_strcmp(tb[TCA_IPT_TABLE], "mangle")) + goto err1; + } - err = -ENOMEM; - tname = kmalloc(IFNAMSIZ, GFP_KERNEL); + tname = kstrdup("mangle", GFP_KERNEL); if (unlikely(!tname)) goto err1; - if (tb[TCA_IPT_TABLE] == NULL || - nla_strscpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) - strcpy(tname, "mangle"); t = kmemdup(td, td->u.target_size, GFP_KERNEL); if (unlikely(!t)) -- 2.39.2