• Dave Hansen's avatar
    x86/pti: Filter at vma->vm_page_prot population · 316d097c
    Dave Hansen authored
    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: fb43d6cb ("x86/mm: Do not auto-massage page protections")
    Reported-by: default avatarFengguang Wu <fengguang.wu@intel.com>
    Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Acked-by: default avatarIngo Molnar <mingo@kernel.org>
    Cc: Andrea Arcangeli <aarcange@redhat.com>
    Cc: Juergen Gross <jgross@suse.com>
    Cc: Kees Cook <keescook@google.com>
    Cc: Josh Poimboeuf <jpoimboe@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: David Woodhouse <dwmw2@infradead.org>
    Cc: Hugh Dickins <hughd@google.com>
    Cc: linux-mm@kvack.org
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: Nadav Amit <namit@vmware.com>
    Cc: Dan Williams <dan.j.williams@intel.com>
    Cc: Arjan van de Ven <arjan@linux.intel.com>
    Link: https://lkml.kernel.org/r/20180420222028.99D72858@viggo.jf.intel.com
    
    316d097c
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