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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 E3926C433E1 for ; Mon, 18 May 2020 18:08:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BAC3D207D3 for ; Mon, 18 May 2020 18:08:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589825318; bh=Pzq/bwdmcfK0uHr0nFUNIcZXV374tVzgP2Jls2Q/+1I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=GlzqeFMC8xtAe8MicGtO9lpz1jlUgcC9ySONS1ljwQl/BDpqM6jeFhMkePuiUHcuZ bO53h7Zyih425oCUuCUU6/kaRQnFPmNV8WeVIYp3Ac05q8LXWJ6m5rapYoMSbKaSa2 R7xAUMkGov1fvpOjXpUQhyXoepKEILYAf1PAPgtk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387432AbgERSHj (ORCPT ); Mon, 18 May 2020 14:07:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:56576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387426AbgERSHi (ORCPT ); Mon, 18 May 2020 14:07:38 -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 D0A5A20715; Mon, 18 May 2020 18:07:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589825257; bh=Pzq/bwdmcfK0uHr0nFUNIcZXV374tVzgP2Jls2Q/+1I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Lk1RJ1Rb55qMeYzg5BzbKBpFWWz0Kaz/4R6+iHZ5C2DllmyqrICWSgMZngg/WAi4p O0PYE2L7vZ8YUtPQGxEUUTec61aM8kpkGhZaH2NMvsEnv4J6rK3CnVWoqBV19HNSNY t5AQqfr1VCIsnhvXuRMq1DZColVMSMmPa40kmn2E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yonghong Song , Alexei Starovoitov , Andrii Nakryiko Subject: [PATCH 5.6 191/194] bpf: Enforce returning 0 for fentry/fexit progs Date: Mon, 18 May 2020 19:38:01 +0200 Message-Id: <20200518173547.306820163@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173531.455604187@linuxfoundation.org> References: <20200518173531.455604187@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: Yonghong Song commit e92888c72fbdc6f9d07b3b0604c012e81d7c0da7 upstream. Currently, tracing/fentry and tracing/fexit prog return values are not enforced. In trampoline codes, the fentry/fexit prog return values are ignored. Let us enforce it to be 0 to avoid confusion and allows potential future extension. This patch also explicitly added return value checking for tracing/raw_tp, tracing/fmod_ret, and freplace programs such that these program return values can be anything. The purpose are two folds: 1. to make it explicit about return value expectations for these programs in verifier. 2. for tracing prog_type, if a future attach type is added, the default is -ENOTSUPP which will enforce to specify return value ranges explicitly. Fixes: fec56f5890d9 ("bpf: Introduce BPF trampoline") Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200514053206.1298415-1-yhs@fb.com Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/verifier.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6498,6 +6498,22 @@ static int check_return_code(struct bpf_ return 0; range = tnum_const(0); break; + case BPF_PROG_TYPE_TRACING: + switch (env->prog->expected_attach_type) { + case BPF_TRACE_FENTRY: + case BPF_TRACE_FEXIT: + range = tnum_const(0); + break; + case BPF_TRACE_RAW_TP: + return 0; + default: + return -ENOTSUPP; + } + break; + case BPF_PROG_TYPE_EXT: + /* freplace program can return anything as its return value + * depends on the to-be-replaced kernel func or bpf program. + */ default: return 0; }