rpmsg: glink: Fix use after free in open_ack TIMEOUT case

commit ac74ea01860170699fb3b6ea80c0476774c8e94f upstream.

Extra channel reference put when remote sending OPEN_ACK after timeout
causes use-after-free while handling next remote CLOSE command.

Remove extra reference put in timeout case to avoid use-after-free.

Fixes: b4f8e52b89f6 ("rpmsg: Introduce Qualcomm RPM glink driver")
Cc: stable@vger.kernel.org
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 335b47c..539a6b9 100644 (file)
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1106,13 +1106,12 @@ static int qcom_glink_create_remote(struct qcom_glink *glink,
 close_link:
        /*
         * Send a close request to "undo" our open-ack. The close-ack will
-        * release the last reference.
+        * release qcom_glink_send_open_req() reference and the last reference
+        * will be relesed after receiving remote_close or transport unregister
+        * by calling qcom_glink_native_remove().
         */
        qcom_glink_send_close_req(glink, channel);
 
-       /* Release qcom_glink_send_open_req() reference */
-       kref_put(&channel->refcount, qcom_glink_channel_release);
-
        return ret;
 }