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: 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: Sasha Levin <sasha.levin@oracle.com>
diff --git a/mm/memory.c b/mm/memory.c
index d442584..4ffa7b5 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3558,7 +3558,7 @@
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