From 029d9252b116fa52a95150819e62af1f6e420fe5 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Fri, 14 Jul 2017 16:51:23 +1000 Subject: powerpc/mm: Mark __init memory no-execute when STRICT_KERNEL_RWX=y Currently even with STRICT_KERNEL_RWX we leave the __init text marked executable after init, which is bad. Add a hook to mark it NX (no-execute) before we free it, and implement it for radix and hash. Note that we use __init_end as the end address, not _einittext, because overlaps_kernel_text() uses __init_end, because there are additional executable sections other than .init.text between __init_begin and __init_end. Tested on radix and hash with: 0:mon> p $__init_begin *** 400 exception occurred Fixes: 1e0fc9d1eb2b ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs") Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/book3s/64/hash.h | 1 + arch/powerpc/include/asm/book3s/64/pgtable.h | 1 + arch/powerpc/include/asm/book3s/64/radix.h | 1 + arch/powerpc/include/asm/pgtable.h | 7 +++++++ arch/powerpc/mm/mem.c | 1 + arch/powerpc/mm/pgtable-hash64.c | 12 ++++++++++++ arch/powerpc/mm/pgtable-radix.c | 8 ++++++++ arch/powerpc/mm/pgtable_64.c | 8 ++++++++ 8 files changed, 39 insertions(+) (limited to 'arch') diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index 0ce513f2926f..36fc7bfe9e11 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -91,6 +91,7 @@ static inline int hash__pgd_bad(pgd_t pgd) } #ifdef CONFIG_STRICT_KERNEL_RWX extern void hash__mark_rodata_ro(void); +extern void hash__mark_initmem_nx(void); #endif extern void hpte_need_flush(struct mm_struct *mm, unsigned long addr, diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index c0737c86a362..d1da415e283c 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -1192,5 +1192,6 @@ static inline const int pud_pfn(pud_t pud) BUILD_BUG(); return 0; } + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_BOOK3S_64_PGTABLE_H_ */ diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h index 487709ff6875..544440b5aff3 100644 --- a/arch/powerpc/include/asm/book3s/64/radix.h +++ b/arch/powerpc/include/asm/book3s/64/radix.h @@ -118,6 +118,7 @@ #ifdef CONFIG_STRICT_KERNEL_RWX extern void radix__mark_rodata_ro(void); +extern void radix__mark_initmem_nx(void); #endif static inline unsigned long __radix_pte_update(pte_t *ptep, unsigned long clr, diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h index dd01212935ac..afae9a336136 100644 --- a/arch/powerpc/include/asm/pgtable.h +++ b/arch/powerpc/include/asm/pgtable.h @@ -80,6 +80,13 @@ unsigned long vmalloc_to_phys(void *vmalloc_addr); void pgtable_cache_add(unsigned shift, void (*ctor)(void *)); void pgtable_cache_init(void); + +#ifdef CONFIG_STRICT_KERNEL_RWX +void mark_initmem_nx(void); +#else +static inline void mark_initmem_nx(void) { } +#endif + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_PGTABLE_H */ diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 8541f18694a4..46b4e67d2372 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -402,6 +402,7 @@ void __init mem_init(void) void free_initmem(void) { ppc_md.progress = ppc_printk_progress; + mark_initmem_nx(); free_initmem_default(POISON_FREE_INITMEM); } diff --git a/arch/powerpc/mm/pgtable-hash64.c b/arch/powerpc/mm/pgtable-hash64.c index 73019c52141f..443a2c66a304 100644 --- a/arch/powerpc/mm/pgtable-hash64.c +++ b/arch/powerpc/mm/pgtable-hash64.c @@ -460,4 +460,16 @@ void hash__mark_rodata_ro(void) WARN_ON(!hash__change_memory_range(start, end, PP_RXXX)); } + +void hash__mark_initmem_nx(void) +{ + unsigned long start, end, pp; + + start = (unsigned long)__init_begin; + end = (unsigned long)__init_end; + + pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL)); + + WARN_ON(!hash__change_memory_range(start, end, pp)); +} #endif diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c index 336e52ec652c..5cc50d47ce3f 100644 --- a/arch/powerpc/mm/pgtable-radix.c +++ b/arch/powerpc/mm/pgtable-radix.c @@ -162,6 +162,14 @@ void radix__mark_rodata_ro(void) radix__change_memory_range(start, end, _PAGE_WRITE); } + +void radix__mark_initmem_nx(void) +{ + unsigned long start = (unsigned long)__init_begin; + unsigned long end = (unsigned long)__init_end; + + radix__change_memory_range(start, end, _PAGE_EXEC); +} #endif /* CONFIG_STRICT_KERNEL_RWX */ static inline void __meminit print_mapping(unsigned long start, diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index 5c0b795d656c..0736e94c7615 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -505,4 +505,12 @@ void mark_rodata_ro(void) else hash__mark_rodata_ro(); } + +void mark_initmem_nx(void) +{ + if (radix_enabled()) + radix__mark_initmem_nx(); + else + hash__mark_initmem_nx(); +} #endif -- cgit v1.2.3-59-g8ed1b