From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 EB46022D7A9 for ; Wed, 30 Sep 2026 00:20:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790727623; cv=none; b=rbljo8xSfwYHcpnvpeUXww9ezMzxodrYI9mId9ui388lIvF3eKMa2gLW5RIUrNntZ5V9b4RzPxJN/NHvTNz5F+B5MnsnRjw0uobXwnvbDHMVaBaT69UiFPHZCmSTHAkH0fRytbltVldZbltE2AemG0dTMd/CS6zc7ebF7FH23SM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790727623; c=relaxed/simple; bh=grZ5hJlWe7OAftg+o9KETGwJiXX7n6A0NX1qpNG1GDM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GAGMvMWmkxV2gt7h6TN2b3JCb7ibYf+nm7JNLFLS0RwkNotHPOnLsRqXm+A0nJUWv7ioPWJLfjYieOcijLHyXMiFji0K2x8Sh7g/7GWK1Cbj8iDNSxGXtjK1MbzwOErfjt7iY8iFAP2w38GaphgxKofotAKUCGBRrbb+KEujBEI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mrxJUcmc; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mrxJUcmc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF5061F00893; Wed, 30 Sep 2026 00:20:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790727621; bh=H4o9xKkLiA/6PLFyNGVpD8W1FYdgmNfXn9QsBGn+7kA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=mrxJUcmcH5MBzXu0sqp5p/W8PXab4XbBn0CB2Azg3zUKap2iolv46BqMYcS6D1mex 8qGE9mDAVOyRAg/r2fpyYbz+nvuaF1Tf+JSKtZkGNkthxFUvLJW6UWKNjZe8cv//kC 8EOdwIljF+u17hSg8ZYtRbYY+NELce8pZp7VxQloRtJV0GoU3+kZWlV1wmhcWpaJoE a2f9v8O0Enx/ukX1hpGPALA/AePtcr4GQY+a4eEOVhEFli1EyQh1pGjDNYUyBYqRcM Nm02FNbMm/ktgua4Lg2KF3I79x9R66oah7FqvAp9hwKTRi8rqE1KT+UNtCm4vtlvHS uSLjx0rjBLuAA== From: Sasha Levin To: stable@vger.kernel.org Cc: Ilya Maximets , Axel Mierczuk , Xin Long , Jamal Hadi Salim , Aaron Conole , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.18.y 2/2] net/sched: act_ct: fix helper UAF due to extensions realloc Date: Tue, 29 Sep 2026 20:20:18 -0400 Message-ID: <20260930002018.2933978-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260930002018.2933978-1-sashal@kernel.org> References: <2026092923-during-buffalo-09b7@gregkh> <20260930002018.2933978-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Ilya Maximets [ Upstream commit dad19b59da050cb60d3f7023dac2a042a84bf0bd ] While calling the helpers, a raw pointer to the extensions area is wired into expectations list: -> nf_ct_helper() -> helper->help() -> nf_ct_expect_related_report() -> nf_ct_expect_insert() -> hlist_add_head_rcu(&exp->lnode, &master_help->expectations) In case the connection is not confirmed yet, more extensions can be added afterwards with *_ext_add() calls reallocating the extension space and leaving the now invalid pointer in the expectations list that is later accessed while removing the expectation. Make sure that helpers are called at the end after all the other extensions are already added. Note that the helper rejection now leaves the mark and labels set, but that's not different from how the NAT was handled before or how the mark and the labels were handled on confirmation failure. And there are no atomicity guarantees provided by the API anyway. Fixes: a21b06e73191 ("net: sched: add helper support in act_ct") Cc: stable@vger.kernel.org Reported-by: Axel Mierczuk Signed-off-by: Ilya Maximets Reviewed-by: Xin Long Reviewed-by: Jamal Hadi Salim Reviewed-by: Aaron Conole Link: https://patch.msgid.link/20260921145655.3167436-7-i.maximets@ovn.org Signed-off-by: Jakub Kicinski [ Preserved the existing add_helper condition that upstream had removed. ] Signed-off-by: Sasha Levin --- net/sched/act_ct.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index cbac27ba76afc..c6085b06ec279 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -1088,19 +1088,25 @@ TC_INDIRECT_SCOPE int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a, } } - if (nf_ct_is_confirmed(ct) ? ((!cached && !skip_add) || add_helper) : commit) { - err = nf_ct_helper(skb, ct, ctinfo, family); - if (err != NF_ACCEPT) - goto nf_error; - } - if (commit) { tcf_ct_act_set_mark(ct, p->mark, p->mark_mask); tcf_ct_act_set_labels(ct, p->labels, p->labels_mask); if (!nf_ct_is_confirmed(ct)) nf_conn_act_ct_ext_add(skb, ct, ctinfo); + } + /* Run helpers for the connection if nf_conntrack_in() was executed + * or if we're about to commit. This has to be done after all the + * extensions are already added. + */ + if (nf_ct_is_confirmed(ct) ? ((!cached && !skip_add) || add_helper) : commit) { + err = nf_ct_helper(skb, ct, ctinfo, family); + if (err != NF_ACCEPT) + goto nf_error; + } + + if (commit) { /* This will take care of sending queued events * even if the connection is already confirmed. */ -- 2.53.0