Commit 1c648766 authored by Grazvydas Ignotas's avatar Grazvydas Ignotas Committed by Luis Henriques

mm/memory.c: actually remap enough memory

commit 9cb12d7b 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: default avatarGrazvydas Ignotas <notasas@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent 3ed567d6
...@@ -3566,7 +3566,7 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, ...@@ -3566,7 +3566,7 @@ 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
......
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