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 76EB81F93D for ; Fri, 21 Jul 2023 16:11:49 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EAA4AC433C8; Fri, 21 Jul 2023 16:11:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689955909; bh=K5Q8LuXtV60lEE3DQknT0iAKwqbcXNrVjqM7CKWwELI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OR8xdqOjK2+pzOlSvpd6HYK6r9uJINdV2oqKZSe59ybhr9Nuj72bjUuR+A/SiOMbh XPv7vOdzwNktsLsl8zLxxgxIxiAUCmV5ZRdbyvx4bYjy9YiniZCxGC//7V4HbflIr/ +vLTVVMR0DzHvMnLLuaaXFdTqMV8D1WFyVjB/SEI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, M A Ramdhan , Jamal Hadi Salim , Pedro Tammela , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.4 045/292] net/sched: cls_fw: Fix improper refcount update leads to use-after-free Date: Fri, 21 Jul 2023 18:02:34 +0200 Message-ID: <20230721160530.738697516@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160528.800311148@linuxfoundation.org> References: <20230721160528.800311148@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: M A Ramdhan [ Upstream commit 0323bce598eea038714f941ce2b22541c46d488f ] In the event of a failure in tcf_change_indev(), fw_set_parms() will immediately return an error after incrementing or decrementing reference counter in tcf_bind_filter(). If attacker can control reference counter to zero and make reference freed, leading to use after free. In order to prevent this, move the point of possible failure above the point where the TC_FW_CLASSID is handled. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: M A Ramdhan Signed-off-by: M A Ramdhan Acked-by: Jamal Hadi Salim Reviewed-by: Pedro Tammela Message-ID: <20230705161530.52003-1-ramdhan@starlabs.sg> Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/cls_fw.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c index ae9439a6c56c9..8641f80593179 100644 --- a/net/sched/cls_fw.c +++ b/net/sched/cls_fw.c @@ -212,11 +212,6 @@ static int fw_set_parms(struct net *net, struct tcf_proto *tp, if (err < 0) return err; - if (tb[TCA_FW_CLASSID]) { - f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]); - tcf_bind_filter(tp, &f->res, base); - } - if (tb[TCA_FW_INDEV]) { int ret; ret = tcf_change_indev(net, tb[TCA_FW_INDEV], extack); @@ -233,6 +228,11 @@ static int fw_set_parms(struct net *net, struct tcf_proto *tp, } else if (head->mask != 0xFFFFFFFF) return err; + if (tb[TCA_FW_CLASSID]) { + f->res.classid = nla_get_u32(tb[TCA_FW_CLASSID]); + tcf_bind_filter(tp, &f->res, base); + } + return 0; } -- 2.39.2