diff options
| author | Halil Pasic <pasic@linux.ibm.com> | 2018-09-26 18:48:29 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2018-12-06 14:22:34 -0500 |
| commit | 2448a299ec416a80f699940a86f4a6d9a4f643b1 (patch) | |
| tree | b679315127c7e5b490082e9162f58c408f4f06b4 | |
| parent | c38f57da428b033f2721b611d84b1f40bde674a8 (diff) | |
| download | linux-2448a299ec416a80f699940a86f4a6d9a4f643b1.tar.bz2 | |
virtio/s390: avoid race on vcdev->config
Currently we have a race on vcdev->config in virtio_ccw_get_config() and
in virtio_ccw_set_config().
This normally does not cause problems, as these are usually infrequent
operations. However, for some devices writing to/reading from the config
space can be triggered through sysfs attributes. For these, userspace can
force the race by increasing the frequency.
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Cc: stable@vger.kernel.org
Message-Id: <20180925121309.58524-2-pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
| -rw-r--r-- | drivers/s390/virtio/virtio_ccw.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c index 97b6f197f007..c94f38ef9a94 100644 --- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c @@ -828,6 +828,7 @@ static void virtio_ccw_get_config(struct virtio_device *vdev, int ret; struct ccw1 *ccw; void *config_area; + unsigned long flags; ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL); if (!ccw) @@ -846,11 +847,13 @@ static void virtio_ccw_get_config(struct virtio_device *vdev, if (ret) goto out_free; + spin_lock_irqsave(&vcdev->lock, flags); memcpy(vcdev->config, config_area, offset + len); - if (buf) - memcpy(buf, &vcdev->config[offset], len); if (vcdev->config_ready < offset + len) vcdev->config_ready = offset + len; + spin_unlock_irqrestore(&vcdev->lock, flags); + if (buf) + memcpy(buf, config_area + offset, len); out_free: kfree(config_area); @@ -864,6 +867,7 @@ static void virtio_ccw_set_config(struct virtio_device *vdev, struct virtio_ccw_device *vcdev = to_vc_device(vdev); struct ccw1 *ccw; void *config_area; + unsigned long flags; ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL); if (!ccw) @@ -876,9 +880,11 @@ static void virtio_ccw_set_config(struct virtio_device *vdev, /* Make sure we don't overwrite fields. */ if (vcdev->config_ready < offset) virtio_ccw_get_config(vdev, 0, NULL, offset); + spin_lock_irqsave(&vcdev->lock, flags); memcpy(&vcdev->config[offset], buf, len); /* Write the config area to the host. */ memcpy(config_area, vcdev->config, sizeof(vcdev->config)); + spin_unlock_irqrestore(&vcdev->lock, flags); ccw->cmd_code = CCW_CMD_WRITE_CONF; ccw->flags = 0; ccw->count = offset + len; |