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soc: qcom: qmi: fix a buffer sizing bug 

In qmi_handle_init(), a buffer is allocated for to hold messages
received through the handle's socket.  Any "normal" messages
(expected by the caller) will have a header prepended, so the
buffer size is adjusted to accomodate that.

The buffer must also be of sufficient size to receive control
messages, so the size is increased if necessary to ensure these
will fit.

Unfortunately the calculation is done wrong, making it possible
for the calculated buffer size to be too small to hold a "normal"
message.  Specifically, if:

  recv_buf_size > sizeof(struct qrtr_ctrl_pkt) - sizeof(struct qmi_header)
		AND
  recv_buf_size < sizeof(struct qrtr_ctrl_pkt)

the current logic will use sizeof(struct qrtr_ctrl_pkt) as the
receive buffer size, which is not enough to hold the maximum
"normal" message plus its header.  Currently this problem occurs
for (13 < recv_buf_size < 20).

This patch corrects this.

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Andy Gross <andy.gross@linaro.org>
This commit is contained in:
Alex Elder 2018-04-27 09:08:17 -05:00 committed by Andy Gross
parent 488de0317b
commit 7df5ff258b
1 changed files with 3 additions and 2 deletions
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5
drivers/soc/qcom/qmi_interface.c
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@ -639,10 +639,11 @@ int qmi_handle_init(struct qmi_handle *qmi, size_t recv_buf_size,
if (ops)
qmi->ops = *ops;
/* Make room for the header */
recv_buf_size += sizeof(struct qmi_header);
/* Must also be sufficient to hold a control packet */
if (recv_buf_size < sizeof(struct qrtr_ctrl_pkt))
recv_buf_size = sizeof(struct qrtr_ctrl_pkt);
else
recv_buf_size += sizeof(struct qmi_header);
qmi->recv_buf_size = recv_buf_size;
qmi->recv_buf = kzalloc(recv_buf_size, GFP_KERNEL);