diff options
| author |   Christoph Hellwig <hch@lst.de> | 2017-01-09 08:56:23 -0700 |
|---|---|---|
| committer |   Jens Axboe <axboe@fb.com> | 2017-01-10 13:30:50 -0700 |
| commit | a14d749fcebe97ddf6af6db3d1f6ece85c9ddcb9 (patch) | |
| tree | b441577383d9ca1586799d28a031d99e9d6e967d /drivers/block/virtio_blk.c | |
| parent | do_direct_IO: Use inode->i_blkbits to compute block count to be cleaned (diff) | |
| download | linux-dev-a14d749fcebe97ddf6af6db3d1f6ece85c9ddcb9.tar.xz linux-dev-a14d749fcebe97ddf6af6db3d1f6ece85c9ddcb9.zip | |
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>
Diffstat (limited to 'drivers/block/virtio_blk.c')
| -rw-r--r-- | drivers/block/virtio_blk.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 5545a679abd8..3c3b8f601469 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -56,6 +56,7 @@ struct virtblk_req { struct virtio_blk_outhdr out_hdr; struct virtio_scsi_inhdr in_hdr; u8 status; + u8 sense[SCSI_SENSE_BUFFERSIZE]; struct scatterlist sg[]; }; @@ -102,7 +103,8 @@ static int __virtblk_add_req(struct virtqueue *vq, } if (type == cpu_to_virtio32(vq->vdev, VIRTIO_BLK_T_SCSI_CMD)) { - sg_init_one(&sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE); + memcpy(vbr->sense, vbr->req->sense, SCSI_SENSE_BUFFERSIZE); + sg_init_one(&sense, vbr->sense, SCSI_SENSE_BUFFERSIZE); sgs[num_out + num_in++] = &sense; sg_init_one(&inhdr, &vbr->in_hdr, sizeof(vbr->in_hdr)); sgs[num_out + num_in++] = &inhdr; |