Messages in this thread Patch in this message | | | From | Atish Patra <> | Subject | [PATCH v2 3/6] RISC-V: Enforce protections for kernel sections early | Date | Mon, 26 Oct 2020 16:02:51 -0700 |
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Currently, all memblocks are mapped with PAGE_KERNEL_EXEC and the strict permissions are only enforced after /init starts. This leaves the kernel vulnerable from possible buggy built-in modules.
Apply permissions to individual sections as early as possible.
Signed-off-by: Atish Patra <atish.patra@wdc.com> --- arch/riscv/include/asm/set_memory.h | 2 ++ arch/riscv/kernel/setup.c | 2 ++ arch/riscv/mm/init.c | 11 +++++++++-- 3 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h index 4c5bae7ca01c..4cc3a4e2afd3 100644 --- a/arch/riscv/include/asm/set_memory.h +++ b/arch/riscv/include/asm/set_memory.h @@ -15,11 +15,13 @@ 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); +void protect_kernel_text_data(void); #else static inline int set_memory_ro(unsigned long addr, int numpages) { return 0; } static inline int set_memory_rw(unsigned long addr, int numpages) { return 0; } static inline int set_memory_x(unsigned long addr, int numpages) { return 0; } static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; } +static inline void protect_kernel_text_data(void) {}; #endif int set_direct_map_invalid_noflush(struct page *page); diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 7d6a04ae3929..b722c5bf892c 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -22,6 +22,7 @@ #include <asm/cpu_ops.h> #include <asm/early_ioremap.h> #include <asm/setup.h> +#include <asm/set_memory.h> #include <asm/sections.h> #include <asm/sbi.h> #include <asm/tlbflush.h> @@ -92,6 +93,7 @@ void __init setup_arch(char **cmdline_p) #if IS_ENABLED(CONFIG_RISCV_SBI) sbi_init(); #endif + protect_kernel_text_data(); #ifdef CONFIG_SWIOTLB swiotlb_init(1); #endif diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index ea933b789a88..5f196f8158d4 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -608,7 +608,7 @@ static inline void setup_vm_final(void) #endif /* CONFIG_MMU */ #ifdef CONFIG_STRICT_KERNEL_RWX -void mark_rodata_ro(void) +void protect_kernel_text_data(void) { unsigned long text_start = (unsigned long)_text; unsigned long text_end = (unsigned long)_etext; @@ -617,9 +617,16 @@ void mark_rodata_ro(void) 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); +} + +void mark_rodata_ro(void) +{ + unsigned long rodata_start = (unsigned long)__start_rodata; + unsigned long data_start = (unsigned long)_data; + + set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT); debug_checkwx(); } -- 2.25.1
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