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comedi: vmk80xx: fix transfer-buffer overflows
commita23461c474
upstream. The driver uses endpoint-sized USB transfer buffers but up until recently had no sanity checks on the sizes. Commite1f13c879a
("staging: comedi: check validity of wMaxPacketSize of usb endpoints found") inadvertently fixed NULL-pointer dereferences when accessing the transfer buffers in case a malicious device has a zero wMaxPacketSize. Make sure to allocate buffers large enough to handle also the other accesses that are done without a size check (e.g. byte 18 in vmk80xx_cnt_insn_read() for the VMK8061_MODEL) to avoid writing beyond the buffers, for example, when doing descriptor fuzzing. The original driver was for a low-speed device with 8-byte buffers. Support was later added for a device that uses bulk transfers and is presumably a full-speed device with a maximum 64-byte wMaxPacketSize. Fixes:985cafccbf
("Staging: Comedi: vmk80xx: Add k8061 support") Cc: stable@vger.kernel.org # 2.6.31 Signed-off-by: Johan Hovold <johan@kernel.org> Reviewed-by: Ian Abbott <abbotti@mev.co.uk> Link: https://lore.kernel.org/r/20211025114532.4599-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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parent
ef143dc0c3
commit
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1 changed files with 4 additions and 2 deletions
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@ -90,6 +90,8 @@ enum {
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#define IC3_VERSION BIT(0)
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#define IC6_VERSION BIT(1)
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#define MIN_BUF_SIZE 64
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enum vmk80xx_model {
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VMK8055_MODEL,
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VMK8061_MODEL
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@ -678,12 +680,12 @@ static int vmk80xx_alloc_usb_buffers(struct comedi_device *dev)
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struct vmk80xx_private *devpriv = dev->private;
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size_t size;
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size = usb_endpoint_maxp(devpriv->ep_rx);
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size = max(usb_endpoint_maxp(devpriv->ep_rx), MIN_BUF_SIZE);
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devpriv->usb_rx_buf = kzalloc(size, GFP_KERNEL);
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if (!devpriv->usb_rx_buf)
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return -ENOMEM;
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size = usb_endpoint_maxp(devpriv->ep_tx);
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size = max(usb_endpoint_maxp(devpriv->ep_rx), MIN_BUF_SIZE);
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devpriv->usb_tx_buf = kzalloc(size, GFP_KERNEL);
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if (!devpriv->usb_tx_buf)
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return -ENOMEM;
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