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 991DD17744 for ; Wed, 9 Aug 2023 11:31:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC4C6C433C8; Wed, 9 Aug 2023 11:31:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691580670; bh=OrF6ETYTalG4nUTcZCg/SrKqQgjs87t1zsVu8Vjt/ag=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SuAP2AhoTxD0PUCgbu7r7Y4lI1Y0kVZtJU/DY3BG745GMku8B5oScOa2tO4czZ78z YqADfXIHuibTz7qO5OlvJYBmObSp5PcmAnm9plpfrQwKLjSJmlrdIMIQ0y18FM9xlp yAVUMy5BSEUNNzgDkyTyT5ysCM88XIjxt+UobR0A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, valis , M A Ramdhan , Jamal Hadi Salim , Victor Nogueira , Pedro Tammela , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.4 107/154] net/sched: cls_u32: No longer copy tcf_result on update to avoid use-after-free Date: Wed, 9 Aug 2023 12:42:18 +0200 Message-ID: <20230809103640.497617136@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103636.887175326@linuxfoundation.org> References: <20230809103636.887175326@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: valis [ Upstream commit 3044b16e7c6fe5d24b1cdbcf1bd0a9d92d1ebd81 ] When u32_change() is called on an existing filter, the whole tcf_result struct is always copied into the new instance of the filter. This causes a problem when updating a filter bound to a class, as tcf_unbind_filter() is always called on the old instance in the success path, decreasing filter_cnt of the still referenced class and allowing it to be deleted, leading to a use-after-free. Fix this by no longer copying the tcf_result struct from the old filter. Fixes: de5df63228fc ("net: sched: cls_u32 changes to knode must appear atomic to readers") Reported-by: valis Reported-by: M A Ramdhan Signed-off-by: valis Signed-off-by: Jamal Hadi Salim Reviewed-by: Victor Nogueira Reviewed-by: Pedro Tammela Reviewed-by: M A Ramdhan Link: https://lore.kernel.org/r/20230729123202.72406-2-jhs@mojatatu.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/cls_u32.c | 1 - 1 file changed, 1 deletion(-) diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c index 316ccbb01b55f..65598207a2fcb 100644 --- a/net/sched/cls_u32.c +++ b/net/sched/cls_u32.c @@ -814,7 +814,6 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp, new->ifindex = n->ifindex; new->fshift = n->fshift; - new->res = n->res; new->flags = n->flags; RCU_INIT_POINTER(new->ht_down, ht); -- 2.40.1