Commit 463fb5a2 authored Feb 12, 2015 by Grazvydas Ignotas Committed by Sasha Levin Mar 14, 2015

mm/memory.c: actually remap enough memory



commit 9cb12d7b4ccaa976f97ce0c5fd0f1b6a83bc2a75 upstream.

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: 28b2ee20 ("access_process_vm device memory infrastructure")
Signed-off-by: Grazvydas Ignotas <notasas@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent 42af81da

mm/memory.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -3558,7 +3558,7 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
		if (follow_phys(vma, addr, write, &prot, &phys_addr))
		return -EINVAL;

		maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
		maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot);
		if (write)
		memcpy_toio(maddr + offset, buf, len);
		else