mirror of
https://github.com/torvalds/linux.git
synced 2024-12-21 18:42:44 +00:00
9ccaf77cf0
This removes the CONFIG_DEBUG_RODATA option and makes it always enabled. This simplifies the code and also makes it clearer that read-only mapped memory is just as fundamental a security feature in kernel-space as it is in user-space. Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: David Brown <david.brown@linaro.org> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Emese Revfy <re.emese@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathias Krause <minipli@googlemail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: PaX Team <pageexec@freemail.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel-hardening@lists.openwall.com Cc: linux-arch <linux-arch@vger.kernel.org> Link: http://lkml.kernel.org/r/1455748879-21872-4-git-send-email-keescook@chromium.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
81 lines
2.1 KiB
C
81 lines
2.1 KiB
C
/*
|
|
* test_rodata.c: functional test for mark_rodata_ro function
|
|
*
|
|
* (C) Copyright 2008 Intel Corporation
|
|
* Author: Arjan van de Ven <arjan@linux.intel.com>
|
|
*
|
|
* 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/module.h>
|
|
#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;
|
|
}
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("Testcase for marking rodata as read-only");
|
|
MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");
|