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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F2ACC433F5 for ; Sat, 7 May 2022 19:15:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1387041AbiEGTSn (ORCPT ); Sat, 7 May 2022 15:18:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229437AbiEGTSl (ORCPT ); Sat, 7 May 2022 15:18:41 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B30AF28980; Sat, 7 May 2022 12:14:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=/znyXJRLDsok/YXirIxLkxYec6QFvnOe+R9jljS85JE=; b=V5byyGjS+aQTtTXriJ+35IDUKR v3q+TWlwj4c97wcCcmG8DlQY+MLorVgC38EJB7oc1omiLMr2+FTBkkNT4GK2gGUFTKhw71ormve2g jQ+VriF3FmMYXJH5iKuw6xPC2FmfoHlPfaGz/SlL/EANgoW+fsRQ4Zsg0rKqQnLsKE0P3JqP/9YQZ TaGz6w1h9ZZrYf0zs9Z3e/rtASJOB7tPUOKXX0ZVHJqa1aaxyv4ebPkedCgnz/d1FNDoXO57GrBmo 1ivFTOe7e/CW+pCiPC4L2awJ8+JiW93SfrwgPIBj4WwwFVbeoisk1oVBiEC1/IgehgiBIJH2PdtBN kiMQWe+w==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nnPt9-0085Um-Iu; Sat, 07 May 2022 19:14:47 +0000 Date: Sat, 7 May 2022 12:14:47 -0700 From: Luis Chamberlain To: Christophe Leroy Cc: Herbert Xu , "linux-kernel@vger.kernel.org" , "linux-modules@vger.kernel.org" , linuxppc-dev , "fnovak@us.ibm.com" Subject: Re: request_module DoS Message-ID: References: <77ecde32-e868-5804-d9a5-3bb22d314777@csgroup.eu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Luis Chamberlain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 07, 2022 at 01:02:20AM -0700, Luis Chamberlain wrote: > You can try to reproduce by using adding a new test type for crypto-aegis256 > on lib/test_kmod.c. These tests however can try something similar but other > modules. > > /tools/testing/selftests/kmod/kmod.sh -t 0008 > /tools/testing/selftests/kmod/kmod.sh -t 0009 > > I can't decipher this yet. Without testing it... but something like this might be an easier reproducer: diff --git a/tools/testing/selftests/kmod/kmod.sh b/tools/testing/selftests/kmod/kmod.sh index afd42387e8b2..48b6b5ec6c1e 100755 --- a/tools/testing/selftests/kmod/kmod.sh +++ b/tools/testing/selftests/kmod/kmod.sh @@ -41,6 +41,7 @@ set -e TEST_NAME="kmod" TEST_DRIVER="test_${TEST_NAME}" TEST_DIR=$(dirname $0) +PROC_CONFIG="/proc/config.gz" # This represents # @@ -65,6 +66,7 @@ ALL_TESTS="$ALL_TESTS 0010:1:1" ALL_TESTS="$ALL_TESTS 0011:1:1" ALL_TESTS="$ALL_TESTS 0012:1:1" ALL_TESTS="$ALL_TESTS 0013:1:1" +ALL_TESTS="$ALL_TESTS 0014:150:1" # Kselftest framework requirement - SKIP code is 4. ksft_skip=4 @@ -79,6 +81,19 @@ test_modprobe() fi } +kconfig_has() +{ + if [ -f $PROC_CONFIG ]; then + if zgrep -q $1 $PROC_CONFIG 2>/dev/null; then + echo "yes" + else + echo "no" + fi + else + echo "no" + fi +} + function allow_user_defaults() { if [ -z $DEFAULT_KMOD_DRIVER ]; then @@ -106,6 +121,8 @@ function allow_user_defaults() fi MODPROBE_LIMIT_FILE="${PROC_DIR}/kmod-limit" + HAS_CRYPTO_AEGIS256_MOD="$(kconfig_has CONFIG_CRYPTO_AEGIS256=m)" + HAS_CRYPTO_AEGIS256_BUILTIN="$(kconfig_has CONFIG_CRYPTO_AEGIS256=y)" } test_reqs() @@ -504,6 +521,21 @@ kmod_test_0013() "cat /sys/module/${DEFAULT_KMOD_DRIVER}/sections/.*text | head -n1" } +kmod_test_0014() +{ + kmod_defaults_driver + MODPROBE_LIMIT=$(config_get_modprobe_limit) + let EXTRA=$MODPROBE_LIMIT/6 + config_set_driver crypto-aegis256 + config_num_thread_limit_extra $EXTRA + config_trigger ${FUNCNAME[0]} + if [[ "$HAS_CRYPTO_AEGIS256_MOD" == "yes" || "$HAS_CRYPTO_AEGIS256_BUILTIN" == "yes" ]]; then + config_expect_result ${FUNCNAME[0]} SUCCESS + else + config_expect_result ${FUNCNAME[0]} MODULE_NOT_FOUND + fi +} + list_tests() { echo "Test ID list:" @@ -525,6 +557,7 @@ list_tests() echo "0011 x $(get_test_count 0011) - test completely disabling module autoloading" echo "0012 x $(get_test_count 0012) - test /proc/modules address visibility under CAP_SYSLOG" echo "0013 x $(get_test_count 0013) - test /sys/module/*/sections/* visibility under CAP_SYSLOG" + echo "0014 x $(get_test_count 0014) - multithreaded - push kmod_concurrent over max_modprobes for request_module() for crypto-aegis256" } usage()