From: Jinbum Park <jinb.park7@xxxxxxxxx> Subject: mm: add arch-independent testcases for RODATA This patch makes arch-independent testcases for RODATA. Both x86 and x86_64 already have testcases for RODATA, But they are arch-specific because using inline assembly directly. And cacheflush.h is not a suitable location for rodata-test related things. Since they were in cacheflush.h, If someone change the state of CONFIG_DEBUG_RODATA_TEST, It cause overhead of kernel build. To solve the above issues, write arch-independent testcases and move it to shared location. [jinb.park7@xxxxxxxxx: fix config dependency] Link: http://lkml.kernel.org/r/20170209131625.GA16954@pjb1027-Latitude-E5410 Link: http://lkml.kernel.org/r/20170129105436.GA9303@pjb1027-Latitude-E5410 Signed-off-by: Jinbum Park <jinb.park7@xxxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> Cc: Laura Abbott <labbott@xxxxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: Valentin Rothberg <valentinrothberg@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/x86/Kconfig.debug | 8 -- arch/x86/include/asm/cacheflush.h | 10 --- arch/x86/kernel/Makefile | 1 arch/x86/kernel/test_rodata.c | 75 ---------------------------- arch/x86/mm/init_32.c | 4 - arch/x86/mm/init_64.c | 5 - include/linux/rodata_test.h | 24 ++++++++ init/main.c | 6 +- mm/Kconfig.debug | 7 ++ mm/Makefile | 1 mm/rodata_test.c | 56 ++++++++++++++++++++ 11 files changed, 92 insertions(+), 105 deletions(-) diff -puN arch/x86/Kconfig.debug~mm-add-arch-independent-testcases-for-rodata arch/x86/Kconfig.debug --- a/arch/x86/Kconfig.debug~mm-add-arch-independent-testcases-for-rodata +++ a/arch/x86/Kconfig.debug @@ -74,14 +74,6 @@ config EFI_PGT_DUMP issues with the mapping of the EFI runtime regions into that table. -config DEBUG_RODATA_TEST - bool "Testcase for the marking rodata read-only" - default y - ---help--- - This option enables a testcase for the setting rodata read-only - as well as for the change_page_attr() infrastructure. - If in doubt, say "N" - config DEBUG_WX bool "Warn on W+X mappings at boot" select X86_PTDUMP_CORE diff -puN arch/x86/include/asm/cacheflush.h~mm-add-arch-independent-testcases-for-rodata arch/x86/include/asm/cacheflush.h --- a/arch/x86/include/asm/cacheflush.h~mm-add-arch-independent-testcases-for-rodata +++ a/arch/x86/include/asm/cacheflush.h @@ -90,18 +90,8 @@ void clflush_cache_range(void *addr, uns #define mmio_flush_range(addr, size) clflush_cache_range(addr, size) -extern const int rodata_test_data; extern int kernel_set_to_readonly; void set_kernel_text_rw(void); void set_kernel_text_ro(void); -#ifdef CONFIG_DEBUG_RODATA_TEST -int rodata_test(void); -#else -static inline int rodata_test(void) -{ - return 0; -} -#endif - #endif /* _ASM_X86_CACHEFLUSH_H */ diff -puN arch/x86/kernel/Makefile~mm-add-arch-independent-testcases-for-rodata arch/x86/kernel/Makefile --- a/arch/x86/kernel/Makefile~mm-add-arch-independent-testcases-for-rodata +++ a/arch/x86/kernel/Makefile @@ -100,7 +100,6 @@ obj-$(CONFIG_HPET_TIMER) += hpet.o obj-$(CONFIG_APB_TIMER) += apb_timer.o obj-$(CONFIG_AMD_NB) += amd_nb.o -obj-$(CONFIG_DEBUG_RODATA_TEST) += test_rodata.o obj-$(CONFIG_DEBUG_NMI_SELFTEST) += nmi_selftest.o obj-$(CONFIG_KVM_GUEST) += kvm.o kvmclock.o diff -puN arch/x86/kernel/test_rodata.c~mm-add-arch-independent-testcases-for-rodata /dev/null --- a/arch/x86/kernel/test_rodata.c +++ /dev/null @@ -1,75 +0,0 @@ -/* - * test_rodata.c: functional test for mark_rodata_ro function - * - * (C) Copyright 2008 Intel Corporation - * Author: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; version 2 - * of the License. - */ -#include <asm/cacheflush.h> -#include <asm/sections.h> -#include <asm/asm.h> - -int rodata_test(void) -{ - unsigned long result; - unsigned long start, end; - - /* test 1: read the value */ - /* If this test fails, some previous testrun has clobbered the state */ - if (!rodata_test_data) { - printk(KERN_ERR "rodata_test: test 1 fails (start data)\n"); - return -ENODEV; - } - - /* test 2: write to the variable; this should fault */ - /* - * If this test fails, we managed to overwrite the data - * - * This is written in assembly to be able to catch the - * exception that is supposed to happen in the correct - * case - */ - - result = 1; - asm volatile( - "0: mov %[zero],(%[rodata_test])\n" - " mov %[zero], %[rslt]\n" - "1:\n" - ".section .fixup,\"ax\"\n" - "2: jmp 1b\n" - ".previous\n" - _ASM_EXTABLE(0b,2b) - : [rslt] "=r" (result) - : [rodata_test] "r" (&rodata_test_data), [zero] "r" (0UL) - ); - - - if (!result) { - printk(KERN_ERR "rodata_test: test data was not read only\n"); - return -ENODEV; - } - - /* test 3: check the value hasn't changed */ - /* If this test fails, we managed to overwrite the data */ - if (!rodata_test_data) { - printk(KERN_ERR "rodata_test: Test 3 fails (end data)\n"); - return -ENODEV; - } - /* test 4: check if the rodata section is 4Kb aligned */ - start = (unsigned long)__start_rodata; - end = (unsigned long)__end_rodata; - if (start & (PAGE_SIZE - 1)) { - printk(KERN_ERR "rodata_test: .rodata is not 4k aligned\n"); - return -ENODEV; - } - if (end & (PAGE_SIZE - 1)) { - printk(KERN_ERR "rodata_test: .rodata end is not 4k aligned\n"); - return -ENODEV; - } - - return 0; -} diff -puN arch/x86/mm/init_32.c~mm-add-arch-independent-testcases-for-rodata arch/x86/mm/init_32.c --- a/arch/x86/mm/init_32.c~mm-add-arch-independent-testcases-for-rodata +++ a/arch/x86/mm/init_32.c @@ -864,9 +864,6 @@ static noinline int do_test_wp_bit(void) return flag; } -const int rodata_test_data = 0xC3; -EXPORT_SYMBOL_GPL(rodata_test_data); - int kernel_set_to_readonly __read_mostly; void set_kernel_text_rw(void) @@ -939,7 +936,6 @@ void mark_rodata_ro(void) set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", size >> 10); - rodata_test(); #ifdef CONFIG_CPA_DEBUG printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size); diff -puN arch/x86/mm/init_64.c~mm-add-arch-independent-testcases-for-rodata arch/x86/mm/init_64.c --- a/arch/x86/mm/init_64.c~mm-add-arch-independent-testcases-for-rodata +++ a/arch/x86/mm/init_64.c @@ -1000,9 +1000,6 @@ void __init mem_init(void) mem_init_print_info(NULL); } -const int rodata_test_data = 0xC3; -EXPORT_SYMBOL_GPL(rodata_test_data); - int kernel_set_to_readonly; void set_kernel_text_rw(void) @@ -1071,8 +1068,6 @@ void mark_rodata_ro(void) all_end = roundup((unsigned long)_brk_end, PMD_SIZE); set_memory_nx(text_end, (all_end - text_end) >> PAGE_SHIFT); - rodata_test(); - #ifdef CONFIG_CPA_DEBUG printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, end); set_memory_rw(start, (end-start) >> PAGE_SHIFT); diff -puN /dev/null include/linux/rodata_test.h --- /dev/null +++ a/include/linux/rodata_test.h @@ -0,0 +1,24 @@ +/* + * rodata_test.h: functional test for mark_rodata_ro function + * + * (C) Copyright 2008 Intel Corporation + * Author: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ + +#ifndef _RODATA_TEST_H +#define _RODATA_TEST_H + +#ifdef CONFIG_DEBUG_RODATA_TEST +extern const int rodata_test_data; +void rodata_test(void); +#else +static inline void rodata_test(void) {} +#endif + +#endif /* _RODATA_TEST_H */ + diff -puN init/main.c~mm-add-arch-independent-testcases-for-rodata init/main.c --- a/init/main.c~mm-add-arch-independent-testcases-for-rodata +++ a/init/main.c @@ -82,6 +82,7 @@ #include <linux/proc_ns.h> #include <linux/io.h> #include <linux/cache.h> +#include <linux/rodata_test.h> #include <asm/io.h> #include <asm/bugs.h> @@ -935,9 +936,10 @@ __setup("rodata=", set_debug_rodata); #ifdef CONFIG_STRICT_KERNEL_RWX static void mark_readonly(void) { - if (rodata_enabled) + if (rodata_enabled) { mark_rodata_ro(); - else + rodata_test(); + } else pr_info("Kernel memory protection disabled.\n"); } #else diff -puN mm/Kconfig.debug~mm-add-arch-independent-testcases-for-rodata mm/Kconfig.debug --- a/mm/Kconfig.debug~mm-add-arch-independent-testcases-for-rodata +++ a/mm/Kconfig.debug @@ -90,3 +90,10 @@ config DEBUG_PAGE_REF careful when enabling this feature because it adds about 30 KB to the kernel code. However the runtime performance overhead is virtually nil until the tracepoints are actually enabled. + +config DEBUG_RODATA_TEST + bool "Testcase for the marking rodata read-only" + depends on STRICT_KERNEL_RWX + ---help--- + This option enables a testcase for the setting rodata read-only. + diff -puN mm/Makefile~mm-add-arch-independent-testcases-for-rodata mm/Makefile --- a/mm/Makefile~mm-add-arch-independent-testcases-for-rodata +++ a/mm/Makefile @@ -85,6 +85,7 @@ obj-$(CONFIG_MEMORY_FAILURE) += memory-f obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o +obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o obj-$(CONFIG_PAGE_OWNER) += page_owner.o obj-$(CONFIG_CLEANCACHE) += cleancache.o obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o diff -puN /dev/null mm/rodata_test.c --- /dev/null +++ a/mm/rodata_test.c @@ -0,0 +1,56 @@ +/* + * rodata_test.c: functional test for mark_rodata_ro function + * + * (C) Copyright 2008 Intel Corporation + * Author: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ +#include <linux/uaccess.h> +#include <asm/sections.h> + +const int rodata_test_data = 0xC3; +EXPORT_SYMBOL_GPL(rodata_test_data); + +void rodata_test(void) +{ + unsigned long start, end; + int zero = 0; + + /* test 1: read the value */ + /* If this test fails, some previous testrun has clobbered the state */ + if (!rodata_test_data) { + pr_err("rodata_test: test 1 fails (start data)\n"); + return; + } + + /* test 2: write to the variable; this should fault */ + if (!probe_kernel_write((void *)&rodata_test_data, + (void *)&zero, sizeof(zero))) { + pr_err("rodata_test: test data was not read only\n"); + return; + } + + /* test 3: check the value hasn't changed */ + if (rodata_test_data == zero) { + pr_err("rodata_test: test data was changed\n"); + return; + } + + /* test 4: check if the rodata section is PAGE_SIZE aligned */ + start = (unsigned long)__start_rodata; + end = (unsigned long)__end_rodata; + if (start & (PAGE_SIZE - 1)) { + pr_err("rodata_test: start of .rodata is not page size aligned\n"); + return; + } + if (end & (PAGE_SIZE - 1)) { + pr_err("rodata_test: end of .rodata is not page size aligned\n"); + return; + } + + pr_info("rodata_test: all tests were successful\n"); +} _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
