Commit 11d91a77 authored by Laura Abbott's avatar Laura Abbott Committed by Will Deacon

arm64: Add CONFIG_DEBUG_SET_MODULE_RONX support

In a similar fashion to other architecture, add the infrastructure
and Kconfig to enable DEBUG_SET_MODULE_RONX support. When
enabled, module ranges will be marked read-only/no-execute as
appropriate.
Signed-off-by: default avatarLaura Abbott <lauraa@codeaurora.org>
[will: fixed off-by-one in module end check]
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent b6d4f280
......@@ -43,4 +43,15 @@ config ARM64_RANDOMIZE_TEXT_OFFSET
of TEXT_OFFSET and platforms must not require a specific
value.
config DEBUG_SET_MODULE_RONX
bool "Set loadable kernel module data as NX and text as RO"
depends on MODULES
help
This option helps catch unintended modifications to loadable
kernel module's text and read-only data. It also prevents execution
of module data. Such protection may interfere with run-time code
patching and dynamic kernel tracing - and they might also protect
against certain classes of kernel exploits.
If in doubt, say "N".
endmenu
......@@ -148,4 +148,8 @@ static inline void flush_cache_vunmap(unsigned long start, unsigned long end)
{
}
int set_memory_ro(unsigned long addr, int numpages);
int set_memory_rw(unsigned long addr, int numpages);
int set_memory_x(unsigned long addr, int numpages);
int set_memory_nx(unsigned long addr, int numpages);
#endif
obj-y := dma-mapping.o extable.o fault.o init.o \
cache.o copypage.o flush.o \
ioremap.o mmap.o pgd.o mmu.o \
context.o proc.o
context.o proc.o pageattr.o
obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
/*
* Copyright (c) 2014, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
struct page_change_data {
pgprot_t set_mask;
pgprot_t clear_mask;
};
static int change_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,
void *data)
{
struct page_change_data *cdata = data;
pte_t pte = *ptep;
pte = clear_pte_bit(pte, cdata->clear_mask);
pte = set_pte_bit(pte, cdata->set_mask);
set_pte(ptep, pte);
return 0;
}
static int change_memory_common(unsigned long addr, int numpages,
pgprot_t set_mask, pgprot_t clear_mask)
{
unsigned long start = addr;
unsigned long size = PAGE_SIZE*numpages;
unsigned long end = start + size;
int ret;
struct page_change_data data;
if (!IS_ALIGNED(addr, PAGE_SIZE)) {
addr &= PAGE_MASK;
WARN_ON_ONCE(1);
}
if (!is_module_address(start) || !is_module_address(end - 1))
return -EINVAL;
data.set_mask = set_mask;
data.clear_mask = clear_mask;
ret = apply_to_page_range(&init_mm, start, size, change_page_range,
&data);
flush_tlb_kernel_range(start, end);
return ret;
}
int set_memory_ro(unsigned long addr, int numpages)
{
return change_memory_common(addr, numpages,
__pgprot(PTE_RDONLY),
__pgprot(PTE_WRITE));
}
EXPORT_SYMBOL_GPL(set_memory_ro);
int set_memory_rw(unsigned long addr, int numpages)
{
return change_memory_common(addr, numpages,
__pgprot(PTE_WRITE),
__pgprot(PTE_RDONLY));
}
EXPORT_SYMBOL_GPL(set_memory_rw);
int set_memory_nx(unsigned long addr, int numpages)
{
return change_memory_common(addr, numpages,
__pgprot(PTE_PXN),
__pgprot(0));
}
EXPORT_SYMBOL_GPL(set_memory_nx);
int set_memory_x(unsigned long addr, int numpages)
{
return change_memory_common(addr, numpages,
__pgprot(0),
__pgprot(PTE_PXN));
}
EXPORT_SYMBOL_GPL(set_memory_x);
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