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mm/memory.c: actually remap enough memory

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For whatever reason, generic_access_phys() only remaps one page, but
actually allows to access arbitrary size.  It's quite easy to trigger
large reads, like printing out large structure with gdb, which leads to a
crash.  Fix it by remapping correct size.

Fixes: 28b2ee20c7cb ("access_process_vm device memory infrastructure")
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Grazvydas Ignotas 2015-02-12 15:00:19 -08:00 committed by Linus Torvalds
parent 8f4ab07f4b
commit 9cb12d7b4c
1 changed files with 1 additions and 1 deletions
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mm/memory.c
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@ -3462,7 +3462,7 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
if (follow_phys(vma, addr, write, &prot, &phys_addr)) if (follow_phys(vma, addr, write, &prot, &phys_addr))
return -EINVAL; return -EINVAL;
maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot); maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot);
if (write) if (write)
memcpy_toio(maddr + offset, buf, len); memcpy_toio(maddr + offset, buf, len);
else else