From patchwork Fri Aug 5 23:01:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kyle Huey X-Patchwork-Id: 12937881 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 7D0CFC25B0C for ; Fri, 5 Aug 2022 23:02:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238581AbiHEXCG (ORCPT ); Fri, 5 Aug 2022 19:02:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57368 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238634AbiHEXCF (ORCPT ); Fri, 5 Aug 2022 19:02:05 -0400 Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 490C95FAD1 for ; Fri, 5 Aug 2022 16:02:03 -0700 (PDT) Received: by mail-pf1-x42d.google.com with SMTP id y141so3422395pfb.7 for ; Fri, 05 Aug 2022 16:02:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kylehuey.com; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=nFYDqdYlKjDN/X9hygUy8BrADildhN55ltpacqhkjvk=; b=Ub3SJjm4lKtLgOBKlk6F0NN6b1z1p0/7UOM205dCDKd00WpkwlCyMquyC48vh26HIN AVj+rJuIZ/MSzJYPOHfeasr/8Ptjd9hcbaG7mCh4CcKVIV6KGlLp4LMDfRQLpK0V2uFI sa6gu0npzlMwUn4NaoewDvikeJhWC4WItKEoeY1ka87GBAp0Pggs5I83tZDz3A183AP0 bry8r1oFq0y9dkh7Fnnv9EjGJyJUw8dBejX7HxmYZFF7oFUqAk68mv8/sjxcCYCkeucJ 6KImTMRFEdsmYxb1zT2bEAwb4/oO3nsdvGQYoLB3JZ5jI2Pnz6Zf+4/wNEfb3aGzP6pY 1QaA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=nFYDqdYlKjDN/X9hygUy8BrADildhN55ltpacqhkjvk=; b=C8jJY1jZJjxRSjnxaOk3Kw/THqUSFbHNeqj/0O2DFBrfMouQDirlqTUCwEo1zvszkI ZE22x8FgCYws8hLcKMaYX0tyj22VT/QoeqzKQ7uzmEvjU13ekdXMwfbLAyRKeSQMvMPN DTp48wv3US7+DWqgsBAeZ1lFfUq9Ut7KXTAOwOdISmHWuG2VRmWAo5LMD3sD1CZDg7Pi bSFgNfZL4BJ0ijrO6XL0NC/8dcfzpGFBpWYq/uozJvnsUb3qTB3gEd7JZkULc3YlCkas OSmPfbRseDHoApAEta0Wtu0V6AZv3fsh0rLV6pNK/sZ/1DedRd6kKOERUBYG6/3xCqn1 YibQ== X-Gm-Message-State: ACgBeo0XVqz/gf5roBDCSxpJ42q2nBEw/BArkrhPVL8O5sOTKhkuZQ4S 0d+UvFEQ54TIwKx0zO0KDoYgOg== X-Google-Smtp-Source: AA6agR4bTfP1/w3A+DEkFJCGOJfEqaQeFteArUJJ+Jh14QBa7OAVShI1FIYTgY0tQSaGOH4Gxk7IoQ== X-Received: by 2002:a05:6a00:1248:b0:52b:ca7:f2b6 with SMTP id u8-20020a056a00124800b0052b0ca7f2b6mr8878508pfi.82.1659740522715; Fri, 05 Aug 2022 16:02:02 -0700 (PDT) Received: from minbar.home.kylehuey.com (c-71-198-251-229.hsd1.ca.comcast.net. [71.198.251.229]) by smtp.gmail.com with ESMTPSA id g18-20020a635652000000b0041af82dacf7sm1958702pgm.73.2022.08.05.16.02.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 05 Aug 2022 16:02:02 -0700 (PDT) From: Kyle Huey X-Google-Original-From: Kyle Huey To: Dave Hansen , Thomas Gleixner , Borislav Petkov Cc: Ingo Molnar , x86@kernel.org, "H. Peter Anvin" , Paolo Bonzini , Andy Lutomirski , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Robert O'Callahan , David Manouchehri , Kyle Huey Subject: [PATCH v4 2/2] selftests/vm/pkeys: Add a regression test for setting PKRU through ptrace Date: Fri, 5 Aug 2022 16:01:58 -0700 Message-Id: <20220805230158.39378-2-khuey@kylehuey.com> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220805230158.39378-1-khuey@kylehuey.com> References: <20220805230158.39378-1-khuey@kylehuey.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Kyle Huey This tests PTRACE_SETREGSET with NT_X86_XSTATE modifying PKRU directly and removing the PKRU bit from XSTATE_BV. Signed-off-by: Kyle Huey --- tools/testing/selftests/vm/pkey-x86.h | 12 +++ tools/testing/selftests/vm/protection_keys.c | 88 +++++++++++++++++++- 2 files changed, 98 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/vm/pkey-x86.h b/tools/testing/selftests/vm/pkey-x86.h index b078ce9c6d2a..72c14cd3ddc7 100644 --- a/tools/testing/selftests/vm/pkey-x86.h +++ b/tools/testing/selftests/vm/pkey-x86.h @@ -104,6 +104,18 @@ static inline int cpu_has_pkeys(void) return 1; } +static inline int cpu_max_xsave_size(void) +{ + unsigned long XSTATE_CPUID = 0xd; + unsigned int eax; + unsigned int ebx; + unsigned int ecx; + unsigned int edx; + + __cpuid_count(XSTATE_CPUID, 0, eax, ebx, ecx, edx); + return ecx; +} + static inline u32 pkey_bit_position(int pkey) { return pkey * PKEY_BITS_PER_PKEY; diff --git a/tools/testing/selftests/vm/protection_keys.c b/tools/testing/selftests/vm/protection_keys.c index 291bc1e07842..27759d3ed9cd 100644 --- a/tools/testing/selftests/vm/protection_keys.c +++ b/tools/testing/selftests/vm/protection_keys.c @@ -18,12 +18,13 @@ * do a plain mprotect() to a mprotect_pkey() area and make sure the pkey sticks * * Compile like this: - * gcc -o protection_keys -O2 -g -std=gnu99 -pthread -Wall protection_keys.c -lrt -ldl -lm - * gcc -m32 -o protection_keys_32 -O2 -g -std=gnu99 -pthread -Wall protection_keys.c -lrt -ldl -lm + * gcc -mxsave -o protection_keys -O2 -g -std=gnu99 -pthread -Wall protection_keys.c -lrt -ldl -lm + * gcc -mxsave -m32 -o protection_keys_32 -O2 -g -std=gnu99 -pthread -Wall protection_keys.c -lrt -ldl -lm */ #define _GNU_SOURCE #define __SANE_USERSPACE_TYPES__ #include +#include #include #include #include @@ -1550,6 +1551,86 @@ void test_implicit_mprotect_exec_only_memory(int *ptr, u16 pkey) do_not_expect_pkey_fault("plain read on recently PROT_EXEC area"); } +#if defined(__i386__) || defined(__x86_64__) +void test_ptrace_modifies_pkru(int *ptr, u16 pkey) +{ + pid_t child; + int status, ret; + int pkey_offset = pkey_reg_xstate_offset(); + size_t xsave_size = cpu_max_xsave_size(); + void *xsave; + u32 *pkey_register; + u64 *xstate_bv; + struct iovec iov; + + child = fork(); + pkey_assert(child >= 0); + dprintf3("[%d] fork() ret: %d\n", getpid(), child); + if (!child) { + u32 pkey_register = read_pkey_reg(); + + ptrace(PTRACE_TRACEME, 0, 0, 0); + raise(SIGSTOP); + + /* + * need __read_pkey_reg() version so we do not do shadow_pkey_reg + * checking + */ + if (pkey_register == __read_pkey_reg()) + exit(1); + + raise(SIGSTOP); + + exit(__read_pkey_reg()); + } + + pkey_assert(child == waitpid(child, &status, 0)); + dprintf3("[%d] waitpid(%d) status: %x\n", getpid(), child, status); + pkey_assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP); + + xsave = (void *)malloc(xsave_size); + pkey_assert(xsave > 0); + + iov.iov_base = xsave; + iov.iov_len = xsave_size; + ret = ptrace(PTRACE_GETREGSET, child, (void *)NT_X86_XSTATE, &iov); + pkey_assert(ret == 0); + + pkey_register = (u32 *)(xsave + pkey_offset); + pkey_assert(*pkey_register == read_pkey_reg()); + + *pkey_register = !read_pkey_reg(); + + ret = ptrace(PTRACE_SETREGSET, child, (void *)NT_X86_XSTATE, &iov); + pkey_assert(ret == 0); + + ret = ptrace(PTRACE_CONT, child, 0, 0); + pkey_assert(ret == 0); + + pkey_assert(child == waitpid(child, &status, 0)); + dprintf3("[%d] waitpid(%d) status: %x\n", getpid(), child, status); + pkey_assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP); + + ret = ptrace(PTRACE_GETREGSET, child, (void *)NT_X86_XSTATE, &iov); + pkey_assert(ret == 0); + + xstate_bv = (u64 *)(xsave + 512); + *xstate_bv &= ~(1 << 9); + + ret = ptrace(PTRACE_SETREGSET, child, (void *)NT_X86_XSTATE, &iov); + pkey_assert(ret == 0); + + ret = ptrace(PTRACE_CONT, child, 0, 0); + pkey_assert(ret == 0); + + pkey_assert(child == waitpid(child, &status, 0)); + dprintf3("[%d] waitpid(%d) status: %x\n", getpid(), child, status); + pkey_assert(WIFEXITED(status)); + pkey_assert(WEXITSTATUS(status) == 0); + free(xsave); +} +#endif + void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 pkey) { int size = PAGE_SIZE; @@ -1585,6 +1666,9 @@ void (*pkey_tests[])(int *ptr, u16 pkey) = { test_pkey_syscalls_bad_args, test_pkey_alloc_exhaust, test_pkey_alloc_free_attach_pkey0, +#if defined(__i386__) || defined(__x86_64__) + test_ptrace_modifies_pkru, +#endif }; void run_tests_once(void)