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Verify that the test variable holds the initialization value, rather than any non-zero value. Link: https://lkml.kernel.org/r/386ffda192eb4a26f68c526c496afd48a5cd87ce.1732016064.git.ptesarik@suse.com Signed-off-by: Petr Tesarik <ptesarik@suse.com> Reviewed-by: Kees Cook <kees@kernel.org> Cc: Jinbum Park <jinb.park7@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
53 lines
1.3 KiB
C
53 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* rodata_test.c: functional test for mark_rodata_ro function
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*
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* (C) Copyright 2008 Intel Corporation
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* Author: Arjan van de Ven <arjan@linux.intel.com>
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*/
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#define pr_fmt(fmt) "rodata_test: " fmt
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#include <linux/rodata_test.h>
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#include <linux/uaccess.h>
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#include <linux/mm.h>
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#include <asm/sections.h>
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#define TEST_VALUE 0xC3
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static const int rodata_test_data = TEST_VALUE;
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void rodata_test(void)
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{
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int zero = 0;
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/* test 1: read the value */
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/* If this test fails, some previous testrun has clobbered the state */
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if (unlikely(READ_ONCE(rodata_test_data) != TEST_VALUE)) {
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pr_err("test 1 fails (start data)\n");
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return;
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}
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/* test 2: write to the variable; this should fault */
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if (!copy_to_kernel_nofault((void *)&rodata_test_data,
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(void *)&zero, sizeof(zero))) {
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pr_err("test data was not read only\n");
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return;
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}
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/* test 3: check the value hasn't changed */
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if (unlikely(READ_ONCE(rodata_test_data) != TEST_VALUE)) {
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pr_err("test data was changed\n");
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return;
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}
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/* test 4: check if the rodata section is PAGE_SIZE aligned */
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if (!PAGE_ALIGNED(__start_rodata)) {
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pr_err("start of .rodata is not page size aligned\n");
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return;
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}
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if (!PAGE_ALIGNED(__end_rodata)) {
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pr_err("end of .rodata is not page size aligned\n");
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return;
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}
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pr_info("all tests were successful\n");
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}
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