Messages in this thread Patch in this message | | | From | Zong Li <> | Subject | [PATCH v2 6/9] riscv: add STRICT_KERNEL_RWX support | Date | Mon, 9 Mar 2020 16:22:26 +0800 |
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The commit contains that make text section as non-writable, rodata section as read-only, and data section as non-executable.
The init section should be changed to non-executable.
Signed-off-by: Zong Li <zong.li@sifive.com> --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/set_memory.h | 8 +++++ arch/riscv/mm/init.c | 45 +++++++++++++++++++++++++++++ 3 files changed, 54 insertions(+)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index f524d7e60648..308a4dbc0b39 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -62,6 +62,7 @@ config RISCV select ARCH_HAS_GIGANTIC_PAGE select ARCH_HAS_SET_DIRECT_MAP select ARCH_HAS_SET_MEMORY + select ARCH_HAS_STRICT_KERNEL_RWX select ARCH_WANT_HUGE_PMD_SHARE if 64BIT select SPARSEMEM_STATIC if 32BIT select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h index a91f192063c2..d3076087cb34 100644 --- a/arch/riscv/include/asm/set_memory.h +++ b/arch/riscv/include/asm/set_memory.h @@ -15,6 +15,14 @@ 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); +#ifdef CONFIG_STRICT_KERNEL_RWX +void set_kernel_text_ro(void); +void set_kernel_text_rw(void); +#else +static inline void set_kernel_text_ro(void) { } +static inline void set_kernel_text_rw(void) { } +#endif + int set_direct_map_invalid_noflush(struct page *page); int set_direct_map_default_noflush(struct page *page); diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 965a8cf4829c..0d489cb51d5a 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -12,11 +12,13 @@ #include <linux/sizes.h> #include <linux/of_fdt.h> #include <linux/libfdt.h> +#include <linux/set_memory.h> #include <asm/fixmap.h> #include <asm/tlbflush.h> #include <asm/sections.h> #include <asm/pgtable.h> +#include <asm/ptdump.h> #include <asm/io.h> #include "../kernel/head.h" @@ -477,6 +479,49 @@ static void __init setup_vm_final(void) csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE); local_flush_tlb_all(); } + +#ifdef CONFIG_STRICT_KERNEL_RWX +void set_kernel_text_rw(void) +{ + unsigned long text_start = (unsigned long)_text; + unsigned long text_end = (unsigned long)_etext; + + set_memory_rw(text_start, (text_end - text_start) >> PAGE_SHIFT); +} + +void set_kernel_text_ro(void) +{ + unsigned long text_start = (unsigned long)_text; + unsigned long text_end = (unsigned long)_etext; + + set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT); +} + +void mark_rodata_ro(void) +{ + unsigned long text_start = (unsigned long)_text; + unsigned long text_end = (unsigned long)_etext; + unsigned long rodata_start = (unsigned long)__start_rodata; + unsigned long data_start = (unsigned long)_data; + unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn))); + + set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT); + set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT); + set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT); + set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT); +} +#endif + +void free_initmem(void) +{ + unsigned long init_begin = (unsigned long)__init_begin; + unsigned long init_end = (unsigned long)__init_end; + + /* Make the region as non-execuatble. */ + set_memory_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT); + free_initmem_default(POISON_FREE_INITMEM); +} + #else asmlinkage void __init setup_vm(uintptr_t dtb_pa) { -- 2.25.1
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