From 316d097c4cd4e7f2ef50c40cff2db266593c4ec4 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 20 Apr 2018 15:20:28 -0700 Subject: [PATCH] x86/pti: Filter at vma->vm_page_prot population commit ce9962bf7e22bb3891655c349faff618922d4a73 0day reported warnings at boot on 32-bit systems without NX support: attempted to set unsupported pgprot: 8000000000000025 bits: 8000000000000000 supported: 7fffffffffffffff WARNING: CPU: 0 PID: 1 at arch/x86/include/asm/pgtable.h:540 handle_mm_fault+0xfc1/0xfe0: check_pgprot at arch/x86/include/asm/pgtable.h:535 (inlined by) pfn_pte at arch/x86/include/asm/pgtable.h:549 (inlined by) do_anonymous_page at mm/memory.c:3169 (inlined by) handle_pte_fault at mm/memory.c:3961 (inlined by) __handle_mm_fault at mm/memory.c:4087 (inlined by) handle_mm_fault at mm/memory.c:4124 The problem is that due to the recent commit which removed auto-massaging of page protections, filtering page permissions at PTE creation time is not longer done, so vma->vm_page_prot is passed unfiltered to PTE creation. Filter the page protections before they are installed in vma->vm_page_prot. Fixes: fb43d6cb91 ("x86/mm: Do not auto-massage page protections") Reported-by: Fengguang Wu Signed-off-by: Dave Hansen Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Cc: Andrea Arcangeli Cc: Juergen Gross Cc: Kees Cook Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: David Woodhouse Cc: Hugh Dickins Cc: linux-mm@kvack.org Cc: Linus Torvalds Cc: Borislav Petkov Cc: Andy Lutomirski Cc: Greg Kroah-Hartman Cc: Nadav Amit Cc: Dan Williams Cc: Arjan van de Ven Link: https://lkml.kernel.org/r/20180420222028.99D72858@viggo.jf.intel.com --- arch/x86/Kconfig | 4 ++++ arch/x86/include/asm/pgtable.h | 5 +++++ mm/mmap.c | 11 ++++++++++- 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 00fcf81f2c56..c07f492b871a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -52,6 +52,7 @@ config X86 select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_FAST_MULTIPLIER + select ARCH_HAS_FILTER_PGPROT select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_KCOV if X86_64 @@ -273,6 +274,9 @@ config ARCH_HAS_CPU_RELAX config ARCH_HAS_CACHE_LINE_SIZE def_bool y +config ARCH_HAS_FILTER_PGPROT + def_bool y + config HAVE_SETUP_PER_CPU_AREA def_bool y diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 5f49b4ff0c24..f1633de5a675 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -601,6 +601,11 @@ static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) #define canon_pgprot(p) __pgprot(massage_pgprot(p)) +static inline pgprot_t arch_filter_pgprot(pgprot_t prot) +{ + return canon_pgprot(prot); +} + static inline int is_new_memtype_allowed(u64 paddr, unsigned long size, enum page_cache_mode pcm, enum page_cache_mode new_pcm) diff --git a/mm/mmap.c b/mm/mmap.c index 188f195883b9..9d5968d1e8e3 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -100,11 +100,20 @@ pgprot_t protection_map[16] __ro_after_init = { __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 }; +#ifndef CONFIG_ARCH_HAS_FILTER_PGPROT +static inline pgprot_t arch_filter_pgprot(pgprot_t prot) +{ + return prot; +} +#endif + pgprot_t vm_get_page_prot(unsigned long vm_flags) { - return __pgprot(pgprot_val(protection_map[vm_flags & + pgprot_t ret = __pgprot(pgprot_val(protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | pgprot_val(arch_vm_get_page_prot(vm_flags))); + + return arch_filter_pgprot(ret); } EXPORT_SYMBOL(vm_get_page_prot); -- 2.11.0