From a14d749fcebe97ddf6af6db3d1f6ece85c9ddcb9 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 9 Jan 2017 08:56:23 -0700 Subject: 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 Cc: stable@vger.kernel.org # v4.9+ Signed-off-by: Jens Axboe --- drivers/block/virtio_blk.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'drivers/block/virtio_blk.c') 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; -- cgit v1.2.3 From 6bf6b0aa3da84a3d9126919a94c49c0fb7ee2fb3 Mon Sep 17 00:00:00 2001 From: Omar Sandoval Date: Mon, 9 Jan 2017 11:44:12 -0800 Subject: virtio_blk: fix panic in initialization error path If blk_mq_init_queue() returns an error, it gets assigned to vblk->disk->queue. Then, when we call put_disk(), we end up calling blk_put_queue() with the ERR_PTR, causing a bad dereference. Fix it by only assigning to vblk->disk->queue on success. Signed-off-by: Omar Sandoval Reviewed-by: Jeff Moyer Signed-off-by: Jens Axboe --- drivers/block/virtio_blk.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/block/virtio_blk.c') diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 3c3b8f601469..10332c24f961 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -630,11 +630,12 @@ static int virtblk_probe(struct virtio_device *vdev) if (err) goto out_put_disk; - q = vblk->disk->queue = blk_mq_init_queue(&vblk->tag_set); + q = blk_mq_init_queue(&vblk->tag_set); if (IS_ERR(q)) { err = -ENOMEM; goto out_free_tags; } + vblk->disk->queue = q; q->queuedata = vblk; -- cgit v1.2.3