From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 50A9AC04E84 for ; Wed, 15 May 2019 12:11:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 204D62089E for ; Wed, 15 May 2019 12:11:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557922287; bh=OhOw0vL38yXmaU2eKj8DUsYjAkBuuhupC6ayetxH300=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=kfH2xHasPKv5IEXseKlzZRbTgCyzJaqqYReyAWJgT+HAs8pgN+CpNVAWB8tbECUVh x+AgjEeVoierahiWxWCJCWHIlatB+MrRbasXQ0hUmdmqcm4Tl4iTUVGcfiWIH4opNR 6H7Ku6J+JmUC++J87EGF2pQTiKl8IzN3z6YM4Xk4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728488AbfEOLGl (ORCPT ); Wed, 15 May 2019 07:06:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:37550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728008AbfEOLGk (ORCPT ); Wed, 15 May 2019 07:06:40 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D37FB2173C; Wed, 15 May 2019 11:06:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557918399; bh=OhOw0vL38yXmaU2eKj8DUsYjAkBuuhupC6ayetxH300=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q/HcehkXA9xXxLGj1YdA3tK+Npxk8Q0sAKfWeDLvERf+T8NkOn+1oNduLVSGWPREX CQbmWCAS0A4Dczz3Y+u6WwpilmUUWCOOPBHHvTjHd1/CtBdAPP1unM8+4yg3zXkj0O pMHyAFTFzrJ3eWVW6a1ztDztVy18qGZap6Hqsc5w= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daniel Borkmann , Alexei Starovoitov , "David S. Miller" , Zubin Mithra Subject: [PATCH 4.4 073/266] bpf: reject wrong sized filters earlier Date: Wed, 15 May 2019 12:53:00 +0200 Message-Id: <20190515090724.904798248@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190515090722.696531131@linuxfoundation.org> References: <20190515090722.696531131@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Daniel Borkmann commit f7bd9e36ee4a4ce38e1cddd7effe6c0d9943285b upstream. Add a bpf_check_basics_ok() and reject filters that are of invalid size much earlier, so we don't do any useless work such as invoking bpf_prog_alloc(). Currently, rejection happens in bpf_check_classic() only, but it's really unnecessarily late and they should be rejected at earliest point. While at it, also clean up one bpf_prog_size() to make it consistent with the remaining invocations. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller Signed-off-by: Zubin Mithra Signed-off-by: Greg Kroah-Hartman --- net/core/filter.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) --- a/net/core/filter.c +++ b/net/core/filter.c @@ -742,6 +742,17 @@ static bool chk_code_allowed(u16 code_to return codes[code_to_probe]; } +static bool bpf_check_basics_ok(const struct sock_filter *filter, + unsigned int flen) +{ + if (filter == NULL) + return false; + if (flen == 0 || flen > BPF_MAXINSNS) + return false; + + return true; +} + /** * bpf_check_classic - verify socket filter code * @filter: filter to verify @@ -762,9 +773,6 @@ static int bpf_check_classic(const struc bool anc_found; int pc; - if (flen == 0 || flen > BPF_MAXINSNS) - return -EINVAL; - /* Check the filter code now */ for (pc = 0; pc < flen; pc++) { const struct sock_filter *ftest = &filter[pc]; @@ -1057,7 +1065,7 @@ int bpf_prog_create(struct bpf_prog **pf struct bpf_prog *fp; /* Make sure new filter is there and in the right amounts. */ - if (fprog->filter == NULL) + if (!bpf_check_basics_ok(fprog->filter, fprog->len)) return -EINVAL; fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0); @@ -1104,7 +1112,7 @@ int bpf_prog_create_from_user(struct bpf int err; /* Make sure new filter is there and in the right amounts. */ - if (fprog->filter == NULL) + if (!bpf_check_basics_ok(fprog->filter, fprog->len)) return -EINVAL; fp = bpf_prog_alloc(bpf_prog_size(fprog->len), 0); @@ -1184,7 +1192,6 @@ int __sk_attach_filter(struct sock_fprog bool locked) { unsigned int fsize = bpf_classic_proglen(fprog); - unsigned int bpf_fsize = bpf_prog_size(fprog->len); struct bpf_prog *prog; int err; @@ -1192,10 +1199,10 @@ int __sk_attach_filter(struct sock_fprog return -EPERM; /* Make sure new filter is there and in the right amounts. */ - if (fprog->filter == NULL) + if (!bpf_check_basics_ok(fprog->filter, fprog->len)) return -EINVAL; - prog = bpf_prog_alloc(bpf_fsize, 0); + prog = bpf_prog_alloc(bpf_prog_size(fprog->len), 0); if (!prog) return -ENOMEM;