diff options
| -rw-r--r-- | arch/arm64/Kconfig.debug | 11 | ||||
| -rw-r--r-- | arch/arm64/include/asm/cacheflush.h | 4 | ||||
| -rw-r--r-- | arch/arm64/mm/Makefile | 2 | ||||
| -rw-r--r-- | arch/arm64/mm/pageattr.c | 96 |
4 files changed, 112 insertions, 1 deletions
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index 4ee8e90b7a45..0a12933e50ed 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -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 diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h index f2defe1c380c..689b6379188c 100644 --- a/arch/arm64/include/asm/cacheflush.h +++ b/arch/arm64/include/asm/cacheflush.h @@ -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 diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile index 3ecb56c624d3..c56179ed2c09 100644 --- a/arch/arm64/mm/Makefile +++ b/arch/arm64/mm/Makefile @@ -1,5 +1,5 @@ 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 diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c new file mode 100644 index 000000000000..75e744e4cec5 --- /dev/null +++ b/arch/arm64/mm/pageattr.c @@ -0,0 +1,96 @@ +/* + * 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); |