From patchwork Thu May 20 09:18:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 445613 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 53229C433ED for ; Thu, 20 May 2021 10:16:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3B26661447 for ; Thu, 20 May 2021 10:16:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234695AbhETKRW (ORCPT ); Thu, 20 May 2021 06:17:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:47740 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236473AbhETKPU (ORCPT ); Thu, 20 May 2021 06:15:20 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id F335A6198C; Thu, 20 May 2021 09:45:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621503932; bh=beTbDepfJp+gV3uCFBN0fe35WAaiIPXY1D7wJK7dTI4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uwmiPT2mqQu7OA/m8dpi6/Zu3AVD9l4mmcWLbKEZgRxI00866Mi3cJ69yCW0+aj9M +W6Z6icd7EqWeTlAtoVrqfMoCDpzui+h0L9UEqyGkNQ9Z0aJY3+hutwqolL0aqv93Q eYBB/Io+RQ/IZIvq3VFLs4iUq32/3KoH6RSAOTfI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Samuel Mendoza-Jonas , Frank van der Linden , Ethan Chen , Yonghong Song Subject: [PATCH 4.14 004/323] bpf: Fix backport of "bpf: restrict unknown scalars of mixed signed bounds for unprivileged" Date: Thu, 20 May 2021 11:18:16 +0200 Message-Id: <20210520092120.276176727@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092120.115153432@linuxfoundation.org> References: <20210520092120.115153432@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Samuel Mendoza-Jonas The 4.14 backport of 9d7eceede ("bpf: restrict unknown scalars of mixed signed bounds for unprivileged") adds the PTR_TO_MAP_VALUE check to the wrong location in adjust_ptr_min_max_vals(), most likely because 4.14 doesn't include the commit that updates the if-statement to a switch-statement (aad2eeaf4 "bpf: Simplify ptr_min_max_vals adjustment"). Move the check to the proper location in adjust_ptr_min_max_vals(). Fixes: 17efa65350c5a ("bpf: restrict unknown scalars of mixed signed bounds for unprivileged") Signed-off-by: Samuel Mendoza-Jonas Reviewed-by: Frank van der Linden Reviewed-by: Ethan Chen Acked-by: Yonghong Song Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/verifier.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2204,6 +2204,13 @@ static int adjust_ptr_min_max_vals(struc dst); return -EACCES; } + if (ptr_reg->type == PTR_TO_MAP_VALUE) { + if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) { + verbose("R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n", + off_reg == dst_reg ? dst : src); + return -EACCES; + } + } /* In case of 'scalar += pointer', dst_reg inherits pointer type and id. * The id may be overwritten later if we create a new variable offset. @@ -2349,13 +2356,6 @@ static int adjust_ptr_min_max_vals(struc verbose("R%d bitwise operator %s on pointer prohibited\n", dst, bpf_alu_string[opcode >> 4]); return -EACCES; - case PTR_TO_MAP_VALUE: - if (!env->allow_ptr_leaks && !known && (smin_val < 0) != (smax_val < 0)) { - verbose("R%d has unknown scalar with mixed signed bounds, pointer arithmetic with it prohibited for !root\n", - off_reg == dst_reg ? dst : src); - return -EACCES; - } - /* fall-through */ default: /* other operators (e.g. MUL,LSH) produce non-pointer results */ if (!env->allow_ptr_leaks)