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greybus: operation: fix use-after-free when sending responses

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Fix use-after-free when sending responses due to reference imbalance.

Make sure to take a reference to the operation when sending responses.
This reference is dropped in greybus_data_sent when the message has been
sent, while the initial reference is dropped in gb_operation_work after
processing the corresponding request.

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
This commit is contained in:
Johan Hovold 2015-03-27 12:41:13 +01:00 committed by Greg Kroah-Hartman
parent 37754030b0
commit 0fb5acc401
1 changed files with 12 additions and 3 deletions
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15
drivers/staging/greybus/operation.c
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@ -719,6 +719,8 @@ EXPORT_SYMBOL_GPL(gb_operation_request_send_sync);
*/
int gb_operation_response_send(struct gb_operation *operation, int errno)
{
int ret;
/* Record the result */
if (!gb_operation_result_set(operation, errno)) {
pr_err("request result already set\n");
@ -733,10 +735,17 @@ int gb_operation_response_send(struct gb_operation *operation, int errno)
}
}
/* Reference will be dropped when message has been sent. */
gb_operation_get(operation);
/* Fill in the response header and send it */
operation->response->header->result = gb_operation_errno_map(errno);
return gb_message_send(operation->response);
ret = gb_message_send(operation->response);
if (ret)
gb_operation_put(operation);
return ret;
}
EXPORT_SYMBOL_GPL(gb_operation_response_send);
@ -802,8 +811,8 @@ static void gb_connection_recv_request(struct gb_connection *connection,
* request handler to be the operation's callback function.
*
* The last thing the handler does is send a response
* message. The original reference to the operation will be
* dropped when the response has been sent.
* message. The initial reference to the operation will be
* dropped when the handler returns.
*/
operation->callback = gb_operation_request_handle;
if (gb_operation_result_set(operation, -EINPROGRESS))