On Tue, Sep 05, 2023 at 09:42:28AM +0000, Maximilian Heyne wrote:
> With the recent removal of vm_dev from devres its memory is only freed
> via the callback virtio_mmio_release_dev. However, this only takes
> effect after device_add is called by register_virtio_device. Until then
> it's an unmanaged resource and must be explicitly freed on error exit.
>
> This bug was discovered and resolved using Coverity Static Analysis
> Security Testing (SAST) by Synopsys, Inc.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 55c91fedd03d ("virtio-mmio: don't break lifecycle of vm_dev")
> Signed-off-by: Maximilian Heyne <mheyne@xxxxxxxxx>
> ---
> Please note that I have only compile tested this code.
>
> drivers/virtio/virtio_mmio.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
> index 97760f611295..b2a48d07e973 100644
> --- a/drivers/virtio/virtio_mmio.c
> +++ b/drivers/virtio/virtio_mmio.c
> @@ -631,13 +631,16 @@ static int virtio_mmio_probe(struct platform_device *pdev)
> spin_lock_init(&vm_dev->lock);
>
> vm_dev->base = devm_platform_ioremap_resource(pdev, 0);
> - if (IS_ERR(vm_dev->base))
> + if (IS_ERR(vm_dev->base)) {
> + kfree(vm_dev);
> return PTR_ERR(vm_dev->base);
I have a use-after-free here. Will send a v2 where this is fixed.
> + }
>
> /* Check magic value */
> magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
> if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
> dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
> + kfree(vm_dev);
> return -ENODEV;
> }
>
> @@ -646,6 +649,7 @@ static int virtio_mmio_probe(struct platform_device *pdev)
> if (vm_dev->version < 1 || vm_dev->version > 2) {
> dev_err(&pdev->dev, "Version %ld not supported!\n",
> vm_dev->version);
> + kfree(vm_dev);
> return -ENXIO;
> }
>
> @@ -655,6 +659,7 @@ static int virtio_mmio_probe(struct platform_device *pdev)
> * virtio-mmio device with an ID 0 is a (dummy) placeholder
> * with no function. End probing now with no error reported.
> */
> + kfree(vm_dev);
> return -ENODEV;
> }
> vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
> --
> 2.40.1
>
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