vm audit: add VM_DONTEXPAND to mmap for drivers that need it

Drivers that register a ->fault handler, but do not range-check the
offset argument, must set VM_DONTEXPAND in the vm_flags in order to
prevent an expanding mremap from overflowing the resource.

I've audited the tree and attempted to fix these problems (usually by
adding VM_DONTEXPAND where it is not obvious).

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/relay.c b/kernel/relay.c
index 61134eb7a0c8..7c0373322f18 100644
--- a/kernel/relay.c
+++ b/kernel/relay.c
@@ -92,6 +92,7 @@ static int relay_mmap_buf(struct rchan_buf *buf, struct vm_area_struct *vma)
                 return -EINVAL;
 
         vma->vm_ops = &relay_file_mmap_ops;
+        vma->vm_flags |= VM_DONTEXPAND;
         vma->vm_private_data = buf;
         buf->chan->cb->buf_mapped(buf, filp);