diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2021-05-24 16:40:20 +0100 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2021-07-03 04:50:53 -0400 |
| commit | 63947b3434f475418b9677a393d025c0962c2cf8 (patch) | |
| tree | 96114c339dce8f5912b75e40f65277fccff4cca5 /drivers/block | |
| parent | 7a43ce37cd595ed7b6e6a48bdb3a598e647aa738 (diff) | |
virtio-blk: limit seg_max to a safe value
The struct virtio_blk_config seg_max value is read from the device and
incremented by 2 to account for the request header and status byte
descriptors added by the driver.
In preparation for supporting untrusted virtio-blk devices, protect
against integer overflow and limit the value to a safe maximum.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/20210524154020.98195-1-stefanha@redhat.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'drivers/block')
| -rw-r--r-- | drivers/block/virtio_blk.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index c3e260d5bdd0..4b49df2dfd23 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -21,6 +21,9 @@ #define VQ_NAME_LEN 16 #define MAX_DISCARD_SEGMENTS 256u +/* The maximum number of sg elements that fit into a virtqueue */ +#define VIRTIO_BLK_MAX_SG_ELEMS 32768 + static int major; static DEFINE_IDA(vd_index_ida); @@ -721,7 +724,10 @@ static int virtblk_probe(struct virtio_device *vdev) if (err || !sg_elems) sg_elems = 1; - /* We need an extra sg elements at head and tail. */ + /* Prevent integer overflows and honor max vq size */ + sg_elems = min_t(u32, sg_elems, VIRTIO_BLK_MAX_SG_ELEMS - 2); + + /* We need extra sg elements at head and tail. */ sg_elems += 2; vdev->priv = vblk = kmalloc(sizeof(*vblk), GFP_KERNEL); if (!vblk) { |