releases/3.19.2/mm-memory.c-actually-remap-enough-memory.patch

   1 From 9cb12d7b4ccaa976f97ce0c5fd0f1b6a83bc2a75 Mon Sep 17 00:00:00 2001
   2 From: Grazvydas Ignotas <notasas@gmail.com>
   3 Date: Thu, 12 Feb 2015 15:00:19 -0800
   4 Subject: mm/memory.c: actually remap enough memory
   5
   6 From: Grazvydas Ignotas <notasas@gmail.com>
   7
   8 commit 9cb12d7b4ccaa976f97ce0c5fd0f1b6a83bc2a75 upstream.
   9
  10 For whatever reason, generic_access_phys() only remaps one page, but
  11 actually allows to access arbitrary size.  It's quite easy to trigger
  12 large reads, like printing out large structure with gdb, which leads to a
  13 crash.  Fix it by remapping correct size.
  14
  15 Fixes: 28b2ee20c7cb ("access_process_vm device memory infrastructure")
  16 Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
  17 Cc: Rik van Riel <riel@redhat.com>
  18 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  19 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  21
  22 ---
  23  mm/memory.c |    2 +-
  24  1 file changed, 1 insertion(+), 1 deletion(-)
  25
  26 --- a/mm/memory.c
  27 +++ b/mm/memory.c
  28 @@ -3561,7 +3561,7 @@ int generic_access_phys(struct vm_area_s
  29         if (follow_phys(vma, addr, write, &prot, &phys_addr))
  30                 return -EINVAL;
  31
  32 -       maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
  33 +       maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot);
  34         if (write)
  35                 memcpy_toio(maddr + offset, buf, len);
  36         else