| From | Ben Hutchings <> | Date | Tue, 05 May 2015 02:16:39 +0100 | Subject | [PATCH 3.2 040/221] mm/memory.c: actually remap enough memory |
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3.2.69-rc1 review patch. If anyone has any objections, please let me know.
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From: Grazvydas Ignotas <notasas@gmail.com>
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: 28b2ee20c7cb ("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: Ben Hutchings <ben@decadent.org.uk> --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/memory.c +++ b/mm/memory.c @@ -3831,7 +3831,7 @@ int generic_access_phys(struct vm_area_s 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
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