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authorChristoph Hellwig <hch@lst.de>2017-01-09 08:56:23 -0700
committerJens Axboe <axboe@fb.com>2017-01-10 13:30:50 -0700
commita14d749fcebe97ddf6af6db3d1f6ece85c9ddcb9 (patch)
treeb441577383d9ca1586799d28a031d99e9d6e967d /drivers/block
parentdd545b52a3e1efd9f2c6352dbe95ccd0c53461cc (diff)
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')
-rw-r--r--drivers/block/virtio_blk.c4
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;