From patchwork Mon Apr 15 16:35:24 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Xu X-Patchwork-Id: 13630316 Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 213B182890 for ; Mon, 15 Apr 2024 16:35:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.182 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713198943; cv=none; b=SjlwUrII1nRkaAIznY1QqvH0HNFRYD3/Z2Lx+WHzi9oX7W7tqJZmzuLG3HjwTNiThk5xUL20ZiYYqlVkCYOkiFY6k105WIYZLzr1pw80bvU9UmJijK0TGGXtJ3Bftc8c5UeV5kSeyuXy4Go01uwIQLMbhyscn5dcMdOQTuWwjSA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713198943; c=relaxed/simple; bh=tEqZvV3FTwNDGdXGDfu5US6D8OLXShAXUJ74HD0l3yw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=KBqDDhmeliGYDzb1TGGcV2rt+ZWx9CWvhe9xF/UEZtMbGwGDqb6sqh1Tzp4f/DxafY/355ok3ICRiQCoeMB0O48juOMhyHvoRjDUQc3YGk6tfiSv6b2m9IEU8KQET72tVfIrKdO4nFyXJOlqFWhsyw4sy9ZOQhTK9Bjy7eCkrSc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=KWWw0XX+; arc=none smtp.client-ip=209.85.210.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="KWWw0XX+" Received: by mail-pf1-f182.google.com with SMTP id d2e1a72fcca58-6ed11782727so2900601b3a.1 for ; Mon, 15 Apr 2024 09:35:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1713198941; x=1713803741; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=AJHOXE7W4iXMxi8stv8aQLFD0obJISw2P5aysbaDa0s=; b=KWWw0XX+uRhxngnEB1gxEnR00m+vN8V9cxoyzeZ0ePPrVk+Yh9u3YLJrlE+Y+jPisW uDJ1fvHE9KwRd9r1qgESRWqbyIBgfzfUoPeYN0xhDV5NMuYxHjFiN94VfVbQIRoduUN2 vseEgNBAC9pRk0e4510/tOMcTcPpmCGAcOjsg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1713198941; x=1713803741; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=AJHOXE7W4iXMxi8stv8aQLFD0obJISw2P5aysbaDa0s=; b=tCTRGYfWSK9Q4FAS4X4V28OwpWnDt+6WVbip/A0gJMZRg0T2yihbB2oOMm9DqrVG2/ oYyPG8C1q2Fvm++shgSgmATeS4u7JcLTPcD2jxlbeOjnWnUgJTI97SLLU5B8PzuYyrAo fiB5KgcymvnJGpoxy+mT3gYIVAAinc9QlkzzXoqYNjtvbYpZoZSzR3WjtDhRIr/d4c40 TyKBFDIRf18fdLaZ+618kVri+niNmjOZi8HidQH2KMo8LeJ+TYKtK4GOS+xXvdqxhDqv 5RQbKEG9FhAj9BYmCFjxvkYNclKrEQ1xS4wGff75pwNNXJafvKY1Un/ttACLq+hJeTKH JlhQ== X-Forwarded-Encrypted: i=1; AJvYcCUi7FJIg7EFODC/dheoFGOW5tGdifC0nVZWrkwdP5F36P6pMwlLmffnf1IStOFgCjC8n7dpemWwfNYQm4kDcnyQgBwdzc7I9oVWAQ8Q+wDd X-Gm-Message-State: AOJu0YxignHK8G8y36YjnbGWhDDyGQ4U5YMDsLvplKPsht2WidY/syF2 xCH7XUhpDYF4TGN+51DGynJ0fZkUYg9/vvLZVNgc39zgz0XpTrNyjXUI/cX85Q== X-Google-Smtp-Source: AGHT+IGpxBiXitUV65X12uO9kCt9yTS7pqi2G5lLyGKRXo70DVpYj0l9hUD2hNlk3bYPsgQK0YTsXQ== X-Received: by 2002:a05:6a21:151a:b0:1a9:b3e9:a62c with SMTP id nq26-20020a056a21151a00b001a9b3e9a62cmr8978922pzb.48.1713198941478; Mon, 15 Apr 2024 09:35:41 -0700 (PDT) Received: from localhost (15.4.198.104.bc.googleusercontent.com. [104.198.4.15]) by smtp.gmail.com with UTF8SMTPSA id b13-20020a630c0d000000b005dc4da2121fsm7213902pgl.6.2024.04.15.09.35.40 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Apr 2024 09:35:40 -0700 (PDT) From: jeffxu@chromium.org To: akpm@linux-foundation.org, keescook@chromium.org, jannh@google.com, sroettger@google.com, willy@infradead.org, gregkh@linuxfoundation.org, torvalds@linux-foundation.org, usama.anjum@collabora.com, corbet@lwn.net, Liam.Howlett@oracle.com, surenb@google.com, merimus@google.com, rdunlap@infradead.org Cc: jeffxu@google.com, jorgelo@chromium.org, groeck@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, pedro.falcato@gmail.com, dave.hansen@intel.com, linux-hardening@vger.kernel.org, deraadt@openbsd.org, Jeff Xu Subject: [PATCH v10 5/5] selftest mm/mseal read-only elf memory segment Date: Mon, 15 Apr 2024 16:35:24 +0000 Message-ID: <20240415163527.626541-6-jeffxu@chromium.org> X-Mailer: git-send-email 2.44.0.683.g7961c838ac-goog In-Reply-To: <20240415163527.626541-1-jeffxu@chromium.org> References: <20240415163527.626541-1-jeffxu@chromium.org> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Jeff Xu Sealing read-only of elf mapping so it can't be changed by mprotect. Signed-off-by: Jeff Xu --- tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/seal_elf.c | 183 ++++++++++++++++++++++++++ 3 files changed, 185 insertions(+) create mode 100644 tools/testing/selftests/mm/seal_elf.c diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftests/mm/.gitignore index 98eaa4590f11..0b9ab987601c 100644 --- a/tools/testing/selftests/mm/.gitignore +++ b/tools/testing/selftests/mm/.gitignore @@ -48,3 +48,4 @@ va_high_addr_switch hugetlb_fault_after_madv hugetlb_madv_vs_map mseal_test +seal_elf diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index 95d10fe1b3c1..02392c426759 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -60,6 +60,7 @@ TEST_GEN_FILES += mrelease_test TEST_GEN_FILES += mremap_dontunmap TEST_GEN_FILES += mremap_test TEST_GEN_FILES += mseal_test +TEST_GEN_FILES += seal_elf TEST_GEN_FILES += on-fault-limit TEST_GEN_FILES += pagemap_ioctl TEST_GEN_FILES += thuge-gen diff --git a/tools/testing/selftests/mm/seal_elf.c b/tools/testing/selftests/mm/seal_elf.c new file mode 100644 index 000000000000..61a2f1c94e02 --- /dev/null +++ b/tools/testing/selftests/mm/seal_elf.c @@ -0,0 +1,183 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include "../kselftest.h" +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* + * need those definition for manually build using gcc. + * gcc -I ../../../../usr/include -DDEBUG -O3 -DDEBUG -O3 seal_elf.c -o seal_elf + */ +#define FAIL_TEST_IF_FALSE(c) do {\ + if (!(c)) {\ + ksft_test_result_fail("%s, line:%d\n", __func__, __LINE__);\ + goto test_end;\ + } \ + } \ + while (0) + +#define SKIP_TEST_IF_FALSE(c) do {\ + if (!(c)) {\ + ksft_test_result_skip("%s, line:%d\n", __func__, __LINE__);\ + goto test_end;\ + } \ + } \ + while (0) + + +#define TEST_END_CHECK() {\ + ksft_test_result_pass("%s\n", __func__);\ + return;\ +test_end:\ + return;\ +} + +#ifndef u64 +#define u64 unsigned long long +#endif + +/* + * define sys_xyx to call syscall directly. + */ +static int sys_mseal(void *start, size_t len) +{ + int sret; + + errno = 0; + sret = syscall(__NR_mseal, start, len, 0); + return sret; +} + +static void *sys_mmap(void *addr, unsigned long len, unsigned long prot, + unsigned long flags, unsigned long fd, unsigned long offset) +{ + void *sret; + + errno = 0; + sret = (void *) syscall(__NR_mmap, addr, len, prot, + flags, fd, offset); + return sret; +} + +inline int sys_mprotect(void *ptr, size_t size, unsigned long prot) +{ + int sret; + + errno = 0; + sret = syscall(__NR_mprotect, ptr, size, prot); + return sret; +} + +static bool seal_support(void) +{ + int ret; + void *ptr; + unsigned long page_size = getpagesize(); + + ptr = sys_mmap(NULL, page_size, PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); + if (ptr == (void *) -1) + return false; + + ret = sys_mseal(ptr, page_size); + if (ret < 0) + return false; + + return true; +} + +const char somestr[4096] = {"READONLY"}; + +static void test_seal_elf(void) +{ + int ret; + FILE *maps; + char line[512]; + int size = 0; + uintptr_t addr_start, addr_end; + char prot[5]; + char filename[256]; + unsigned long page_size = getpagesize(); + unsigned long long ptr = (unsigned long long) somestr; + char *somestr2 = (char *)somestr; + + /* + * Modify the protection of readonly somestr + */ + if (((unsigned long long)ptr % page_size) != 0) + ptr = (unsigned long long)ptr & ~(page_size - 1); + + ksft_print_msg("somestr = %s\n", somestr); + ksft_print_msg("change protection to rw\n"); + ret = sys_mprotect((void *)ptr, page_size, PROT_READ|PROT_WRITE); + FAIL_TEST_IF_FALSE(!ret); + *somestr2 = 'A'; + ksft_print_msg("somestr is modified to: %s\n", somestr); + ret = sys_mprotect((void *)ptr, page_size, PROT_READ); + FAIL_TEST_IF_FALSE(!ret); + + maps = fopen("/proc/self/maps", "r"); + FAIL_TEST_IF_FALSE(maps); + + /* + * apply sealing to elf binary + */ + while (fgets(line, sizeof(line), maps)) { + if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*u %255[^\n]", + &addr_start, &addr_end, &prot, &filename) == 4) { + if (strlen(filename)) { + /* + * seal the mapping if read only. + */ + if (strstr(prot, "r-")) { + ret = sys_mseal((void *)addr_start, addr_end - addr_start); + FAIL_TEST_IF_FALSE(!ret); + ksft_print_msg("sealed: %lx-%lx %s %s\n", + addr_start, addr_end, prot, filename); + if ((uintptr_t) somestr >= addr_start && + (uintptr_t) somestr <= addr_end) + ksft_print_msg("mapping for somestr found\n"); + } + } + } + } + fclose(maps); + + ret = sys_mprotect((void *)ptr, page_size, PROT_READ | PROT_WRITE); + FAIL_TEST_IF_FALSE(ret < 0); + ksft_print_msg("somestr is sealed, mprotect is rejected\n"); + + TEST_END_CHECK(); +} + +int main(int argc, char **argv) +{ + bool test_seal = seal_support(); + + ksft_print_header(); + ksft_print_msg("pid=%d\n", getpid()); + + if (!test_seal) + ksft_exit_skip("sealing not supported, check CONFIG_64BIT\n"); + + ksft_set_plan(1); + + test_seal_elf(); + + ksft_finished(); + return 0; +}