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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 0FE69C433E0 for ; Tue, 9 Jun 2020 00:28:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D72EB2078B for ; Tue, 9 Jun 2020 00:28:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591662483; bh=O4sIm0dMTHqRZCNxs3PMb5hcgRJULMMM54RSsYvmZzM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=151XskYgVBKrQyxgsOYe9U2Ty3WFuubWOl6W4DvdN/YjWFLeguhJT808suKMMQadw zVGwdK8XZVqw4eHYZl55lleHkYFmzOwrlTho9Ov68g+SCSQbEgN9EsLtSzyzDZx068 j3IvEyuJZvsL/TRARSmGaE7O1TfOiHI0mv/acWfs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730264AbgFHXQe (ORCPT ); Mon, 8 Jun 2020 19:16:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:33578 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729551AbgFHXNn (ORCPT ); Mon, 8 Jun 2020 19:13:43 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ADBF7214D8; Mon, 8 Jun 2020 23:13:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658022; bh=O4sIm0dMTHqRZCNxs3PMb5hcgRJULMMM54RSsYvmZzM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F1yw1wz+uI9OEFQsyy85GOQZGHGC3KoGlB+D/SIm0JmdbSTAmmD1l3wts9O9c//c6 ic/0LubGEJyDE4eQxEaPXgyJbTzL7zLwOZb0IVHgz4KJJTij391/f4h86OZSLw2S8F MGGaJuS01F2kLvG7WOQmjW/T54rB3TZcAW3IkKb8= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Yonghong Song , Alexei Starovoitov , Andrii Nakryiko , Greg Kroah-Hartman , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 5.6 075/606] bpf: Enforce returning 0 for fentry/fexit progs Date: Mon, 8 Jun 2020 19:03:20 -0400 Message-Id: <20200608231211.3363633-75-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231211.3363633-1-sashal@kernel.org> References: <20200608231211.3363633-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1c53ccbd5b5d..c1bb5be530e9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6498,6 +6498,22 @@ static int check_return_code(struct bpf_verifier_env *env) 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; } -- 2.25.1