virtio_blk: avoid DMA to stack for the sense buffer
authorChristoph Hellwig <hch@lst.de>
Mon, 9 Jan 2017 15:56:23 +0000 (08:56 -0700)
committerJens Axboe <axboe@fb.com>
Tue, 10 Jan 2017 20:30:50 +0000 (13:30 -0700)
commita14d749fcebe97ddf6af6db3d1f6ece85c9ddcb9
treeb441577383d9ca1586799d28a031d99e9d6e967d
parentdd545b52a3e1efd9f2c6352dbe95ccd0c53461cc
virtio_blk: avoid DMA to stack for the sense buffer

Most users of BLOCK_PC requests allocate the sense buffer on the stack,
so to avoid DMA to the stack copy them to a field in the heap allocated
virtblk_req structure.  Without that any attempt at SCSI passthrough I/O,
including the SG_IO ioctl from userspace will crash the kernel.  Note that
this includes running tools like hdparm even when the host does not have
SCSI passthrough enabled.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: Jens Axboe <axboe@fb.com>
drivers/block/virtio_blk.c