lkml.org 
[lkml]   [2018]   [May]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] soc: qcom: qmi: fix a buffer sizing bug
On Fri 27 Apr 07:08 PDT 2018, Alex Elder wrote:

> 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>

Good catch, thanks!

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
> drivers/soc/qcom/qmi_interface.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/qcom/qmi_interface.c b/drivers/soc/qcom/qmi_interface.c
> index 321982277697..938ca41c56cd 100644
> --- a/drivers/soc/qcom/qmi_interface.c
> +++ b/drivers/soc/qcom/qmi_interface.c
> @@ -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);
> --
> 2.14.1
>

\
 
 \ /
  Last update: 2018-05-05 01:35    [W:0.042 / U:6.728 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site