From patchwork Fri Sep 18 10:47:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Boyan Karatotev X-Patchwork-Id: 255200 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=-12.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, 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 28D0DC43463 for ; Fri, 18 Sep 2020 10:48:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8FFC22208 for ; Fri, 18 Sep 2020 10:48:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="o/l08dU0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726361AbgIRKrz (ORCPT ); Fri, 18 Sep 2020 06:47:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726309AbgIRKrt (ORCPT ); Fri, 18 Sep 2020 06:47:49 -0400 Received: from mail-wr1-x441.google.com (mail-wr1-x441.google.com [IPv6:2a00:1450:4864:20::441]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9872C061756; Fri, 18 Sep 2020 03:47:48 -0700 (PDT) Received: by mail-wr1-x441.google.com with SMTP id w5so5126747wrp.8; Fri, 18 Sep 2020 03:47:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=mIUKYQBe5Fl+GZXzuMdAIZ0zeMrQ+6eL85ZD/kHw8aY=; b=o/l08dU0a3iblTzC+cQL18/yCNFr+G6et9Nfymcwn3P7xz+BuqkejV3JvsJI4gVLq+ nN3aArF1cqbbiT00q1Sd0xLznM6Hr9WQAVN12rzM3eQMRX5QkYum4QFvbWnt9upRItHo 1NRxIeeMeeoNyr2KaWG3U4dk97gxDRlY1XYEzwtVstTPU7YFvR9SWxA0orlnIRuKl9Md sycaJp8s0tg9su+5g5VscOmyRIqkulX6lyPNCPJIwTZZplkm/dauDGzaNgbpEyRzTetS uyPUkYK1mmfNZm7AffTQTN/WzdLNN2CXGYq+LSpWj2IkcZ3LhDGMn3HFN6i79mqrO7fW p+YA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=mIUKYQBe5Fl+GZXzuMdAIZ0zeMrQ+6eL85ZD/kHw8aY=; b=Zwkpuos2GP2wY7NqDq8FLiwdmc8TF1kJtQhi7YVyo4Q1lI0NuGSYsz8V8al63P+TMA wqAwtwGSVdIpszMHs/knK78g3C3VBdW1jyOrFPzH9jmljA20TSeG63o1JnEGm2nX3GJY Qchn3UfK801W1ddAsc4Bdv4sMqLav6U2rc5mqTinxdovGKaoKNIwmnry5JpZ+fvdpAkn M2wiyeubQW7k+0M0GKKU8g02PQWFIUDB4IG5ZiZOhEaviP9QZJoOL2qgs55FzbBR4pR8 LMlp4oTuYbm7Tgk11N4ftCzdUapCQr0nxsFpDZGEVDHsAcOL5e+uEK0ShU6oMvB5ffMk 40Rw== X-Gm-Message-State: AOAM533x7JpVsZHUvx02pYfvQ4dZ2SPdBwLVaY2+L+AcmA8JeaJKzqj2 4LwqNw/FEirUuaiOFkqUipQ= X-Google-Smtp-Source: ABdhPJyDY4zAyIqiiJ/zK6mMJVToLY91t8rOydnNP7+wypwPmVLmuAtew63ljrzeKgiu1sV0AjqoKQ== X-Received: by 2002:a5d:430d:: with SMTP id h13mr39405899wrq.41.1600426067296; Fri, 18 Sep 2020 03:47:47 -0700 (PDT) Received: from trantor.home (cpc153975-seac28-2-0-cust722.7-2.cable.virginm.net. [81.109.38.211]) by smtp.gmail.com with ESMTPSA id h4sm5197846wrm.54.2020.09.18.03.47.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 18 Sep 2020 03:47:46 -0700 (PDT) From: Boyan Karatotev To: linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Boyan Karatotev , Boyan Karatotev , Shuah Khan , Catalin Marinas , Will Deacon , Vincenzo Frascino , Amit Daniel Kachhap , Shuah Khan Subject: [PATCH v3 3/4] kselftests/arm64: add PAuth test for whether exec() changes keys Date: Fri, 18 Sep 2020 11:47:14 +0100 Message-Id: <20200918104715.182310-4-boian4o1@gmail.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200918104715.182310-1-boian4o1@gmail.com> References: <20200918104715.182310-1-boian4o1@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Boyan Karatotev Kernel documentation states that it will change PAuth keys on exec() calls. Verify that all keys are correctly switched to new ones. Cc: Shuah Khan Cc: Catalin Marinas Cc: Will Deacon Reviewed-by: Vincenzo Frascino Reviewed-by: Amit Daniel Kachhap Acked-by: Shuah Khan Signed-off-by: Boyan Karatotev --- tools/testing/selftests/arm64/pauth/Makefile | 4 + .../selftests/arm64/pauth/exec_target.c | 34 ++++ tools/testing/selftests/arm64/pauth/helper.h | 10 ++ tools/testing/selftests/arm64/pauth/pac.c | 150 ++++++++++++++++++ 4 files changed, 198 insertions(+) create mode 100644 tools/testing/selftests/arm64/pauth/exec_target.c diff --git a/tools/testing/selftests/arm64/pauth/Makefile b/tools/testing/selftests/arm64/pauth/Makefile index 5c0dd129562f..72e290b0b10c 100644 --- a/tools/testing/selftests/arm64/pauth/Makefile +++ b/tools/testing/selftests/arm64/pauth/Makefile @@ -13,6 +13,7 @@ pauth_cc_support := $(shell if ($(CC) $(CFLAGS) -march=armv8.3-a -E -x c /dev/nu ifeq ($(pauth_cc_support),1) TEST_GEN_PROGS := pac TEST_GEN_FILES := pac_corruptor.o helper.o +TEST_GEN_PROGS_EXTENDED := exec_target endif include ../../lib.mk @@ -30,6 +31,9 @@ $(OUTPUT)/helper.o: helper.c # greater, gcc emits pac* instructions which are not in HINT NOP space, # preventing the tests from occurring at all. Compile for ARMv8.2 so tests can # run on earlier targets and print a meaningful error messages +$(OUTPUT)/exec_target: exec_target.c $(OUTPUT)/helper.o + $(CC) $^ -o $@ $(CFLAGS) -march=armv8.2-a + $(OUTPUT)/pac: pac.c $(OUTPUT)/pac_corruptor.o $(OUTPUT)/helper.o $(CC) $^ -o $@ $(CFLAGS) -march=armv8.2-a endif diff --git a/tools/testing/selftests/arm64/pauth/exec_target.c b/tools/testing/selftests/arm64/pauth/exec_target.c new file mode 100644 index 000000000000..4435600ca400 --- /dev/null +++ b/tools/testing/selftests/arm64/pauth/exec_target.c @@ -0,0 +1,34 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2020 ARM Limited + +#include +#include +#include + +#include "helper.h" + +int main(void) +{ + struct signatures signed_vals; + unsigned long hwcaps; + size_t val; + + fread(&val, sizeof(size_t), 1, stdin); + + /* don't try to execute illegal (unimplemented) instructions) caller + * should have checked this and keep worker simple + */ + hwcaps = getauxval(AT_HWCAP); + + if (hwcaps & HWCAP_PACA) { + signed_vals.keyia = keyia_sign(val); + signed_vals.keyib = keyib_sign(val); + signed_vals.keyda = keyda_sign(val); + signed_vals.keydb = keydb_sign(val); + } + signed_vals.keyg = (hwcaps & HWCAP_PACG) ? keyg_sign(val) : 0; + + fwrite(&signed_vals, sizeof(struct signatures), 1, stdout); + + return 0; +} diff --git a/tools/testing/selftests/arm64/pauth/helper.h b/tools/testing/selftests/arm64/pauth/helper.h index 35c4f3357ae3..652496c7b411 100644 --- a/tools/testing/selftests/arm64/pauth/helper.h +++ b/tools/testing/selftests/arm64/pauth/helper.h @@ -6,6 +6,16 @@ #include +#define NKEYS 5 + +struct signatures { + size_t keyia; + size_t keyib; + size_t keyda; + size_t keydb; + size_t keyg; +}; + void pac_corruptor(void); /* PAuth sign a value with key ia and modifier value 0 */ diff --git a/tools/testing/selftests/arm64/pauth/pac.c b/tools/testing/selftests/arm64/pauth/pac.c index bd3d4c0eca9d..b363ad6a0b50 100644 --- a/tools/testing/selftests/arm64/pauth/pac.c +++ b/tools/testing/selftests/arm64/pauth/pac.c @@ -2,6 +2,8 @@ // Copyright (C) 2020 ARM Limited #include +#include +#include #include #include @@ -28,6 +30,117 @@ do { \ ASSERT_NE(0, hwcaps & HWCAP_PACG) TH_LOG("Generic PAUTH not enabled"); \ } while (0) +void sign_specific(struct signatures *sign, size_t val) +{ + sign->keyia = keyia_sign(val); + sign->keyib = keyib_sign(val); + sign->keyda = keyda_sign(val); + sign->keydb = keydb_sign(val); +} + +void sign_all(struct signatures *sign, size_t val) +{ + sign->keyia = keyia_sign(val); + sign->keyib = keyib_sign(val); + sign->keyda = keyda_sign(val); + sign->keydb = keydb_sign(val); + sign->keyg = keyg_sign(val); +} + +int n_same(struct signatures *old, struct signatures *new, int nkeys) +{ + int res = 0; + + res += old->keyia == new->keyia; + res += old->keyib == new->keyib; + res += old->keyda == new->keyda; + res += old->keydb == new->keydb; + if (nkeys == NKEYS) + res += old->keyg == new->keyg; + + return res; +} + +int exec_sign_all(struct signatures *signed_vals, size_t val) +{ + int new_stdin[2]; + int new_stdout[2]; + int status; + ssize_t ret; + pid_t pid; + + ret = pipe(new_stdin); + if (ret == -1) { + perror("pipe returned error"); + return -1; + } + + ret = pipe(new_stdout); + if (ret == -1) { + perror("pipe returned error"); + return -1; + } + + pid = fork(); + // child + if (pid == 0) { + dup2(new_stdin[0], STDIN_FILENO); + if (ret == -1) { + perror("dup2 returned error"); + exit(1); + } + + dup2(new_stdout[1], STDOUT_FILENO); + if (ret == -1) { + perror("dup2 returned error"); + exit(1); + } + + close(new_stdin[0]); + close(new_stdin[1]); + close(new_stdout[0]); + close(new_stdout[1]); + + ret = execl("exec_target", "exec_target", (char *)NULL); + if (ret == -1) { + perror("exec returned error"); + exit(1); + } + } + + close(new_stdin[0]); + close(new_stdout[1]); + + ret = write(new_stdin[1], &val, sizeof(size_t)); + if (ret == -1) { + perror("write returned error"); + return -1; + } + + /* + * wait for the worker to finish, so that read() reads all data + * will also context switch with worker so that this function can be used + * for context switch tests + */ + waitpid(pid, &status, 0); + if (WIFEXITED(status) == 0) { + fprintf(stderr, "worker exited unexpectedly\n"); + return -1; + } + if (WEXITSTATUS(status) != 0) { + fprintf(stderr, "worker exited with error\n"); + return -1; + } + + ret = read(new_stdout[0], signed_vals, sizeof(struct signatures)); + if (ret == -1) { + perror("read returned error"); + return -1; + } + + return 0; +} + sigjmp_buf jmpbuf; void pac_signal_handler(int signum, siginfo_t *si, void *uc) { @@ -92,4 +205,41 @@ TEST(pac_instructions_not_nop_generic) ASSERT_NE(0, keyg) TH_LOG("keyg instructions did nothing"); } +/* + * fork() does not change keys. Only exec() does so call a worker program. + * Its only job is to sign a value and report back the resutls + */ +TEST(exec_changed_keys) +{ + struct signatures new_keys; + struct signatures old_keys; + int ret; + int same = 10; + int nkeys = NKEYS; + unsigned long hwcaps = getauxval(AT_HWCAP); + + /* generic and data key instructions are not in NOP space. This prevents a SIGILL */ + ASSERT_NE(0, hwcaps & HWCAP_PACA) TH_LOG("PAUTH not enabled"); + if (!(hwcaps & HWCAP_PACG)) { + TH_LOG("WARNING: Generic PAUTH not enabled. Skipping generic key checks"); + nkeys = NKEYS - 1; + } + + for (int i = 0; i < PAC_COLLISION_ATTEMPTS; i++) { + ret = exec_sign_all(&new_keys, i); + ASSERT_EQ(0, ret) TH_LOG("failed to run worker"); + + if (nkeys == NKEYS) + sign_all(&old_keys, i); + else + sign_specific(&old_keys, i); + + ret = n_same(&old_keys, &new_keys, nkeys); + if (ret < same) + same = ret; + } + + ASSERT_EQ(0, same) TH_LOG("exec() did not change %d keys", same); +} + TEST_HARNESS_MAIN