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 05F3F1774C for ; Wed, 9 Aug 2023 11:11:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 791DBC433C7; Wed, 9 Aug 2023 11:11:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1691579469; bh=I3UXroALJLUEpABFaBQQqmNLj4WewaGE1AGtLJ8LP+0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iKcgs/awWwVnFGT6pRKBGrGPduOKDmbnNVv3yi1f7jommEVrOm/MG1zhFrRWaS4Kp YN8BSI+t4HconWo20MiUpIJ8KS+N44zFsuQOIXLhWh4KatvaO7UwGHhKs7WxvQ+bza V/I4TE5nz091XKj+6kdZ6rmupcMCuwPejdDX05Bg= 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 , SeongJae Park Subject: [PATCH 4.14 178/204] net/sched: cls_fw: Fix improper refcount update leads to use-after-free Date: Wed, 9 Aug 2023 12:41:56 +0200 Message-ID: <20230809103648.460763089@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230809103642.552405807@linuxfoundation.org> References: <20230809103642.552405807@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 commit 0323bce598eea038714f941ce2b22541c46d488f upstream. 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: SeongJae Park Signed-off-by: Greg Kroah-Hartman --- net/sched/cls_fw.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/net/sched/cls_fw.c +++ b/net/sched/cls_fw.c @@ -225,11 +225,6 @@ static int fw_set_parms(struct net *net, 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); - } - #ifdef CONFIG_NET_CLS_IND if (tb[TCA_FW_INDEV]) { int ret; @@ -248,6 +243,11 @@ static int fw_set_parms(struct net *net, } 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; }