media: venus: hfi: add check to handle incorrect queue size

qsize represents size of shared queued between driver and video
firmware. Firmware can modify this value to an invalid large value. In
such situation, empty_space will be bigger than the space actually
available. Since new_wr_idx is not checked, so the following code will
result in an OOB write.
...
qsize = qhdr->q_size

if (wr_idx >= rd_idx)
 empty_space = qsize - (wr_idx - rd_idx)
....
if (new_wr_idx < qsize) {
 memcpy(wr_ptr, packet, dwords << 2) --> OOB write

Add check to ensure qsize is within the allocated size while
reading and writing packets into the queue.

Cc: stable@vger.kernel.org
Fixes: d96d3f30c0f2 ("[media] media: venus: hfi: add Venus HFI files")
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Vikash Garodia <quic_vgarodia@quicinc.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c b/drivers/media/platform/qcom/venus/hfi_venus.c
index a9167867063c4140450cb803218d32b5bda32d48..36d3a37db4e8a7967ec5209e78a455cc53eb4933 100644 (file)
--- a/drivers/media/platform/qcom/venus/hfi_venus.c
+++ b/drivers/media/platform/qcom/venus/hfi_venus.c
@@ -187,6 +187,9 @@ static int venus_write_queue(struct venus_hfi_device *hdev,
        /* ensure rd/wr indices's are read from memory */
        rmb();
 
+       if (qsize > IFACEQ_QUEUE_SIZE / 4)
+               return -EINVAL;
+
        if (wr_idx >= rd_idx)
                empty_space = qsize - (wr_idx - rd_idx);
        else
@@ -255,6 +258,9 @@ static int venus_read_queue(struct venus_hfi_device *hdev,
        wr_idx = qhdr->write_idx;
        qsize = qhdr->q_size;
 
+       if (qsize > IFACEQ_QUEUE_SIZE / 4)
+               return -EINVAL;
+
        /* make sure data is valid before using it */
        rmb();