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SubjectRe: [PATCH v4 2/5] connector: use __get_task_comm in proc_comm_connector
On Wed, 13 Oct 2021 10:23:43 +0000
Yafang Shao <laoar.shao@gmail.com> wrote:

> --- a/drivers/connector/cn_proc.c
> +++ b/drivers/connector/cn_proc.c
> @@ -230,7 +230,10 @@ void proc_comm_connector(struct task_struct *task)
> ev->what = PROC_EVENT_COMM;
> ev->event_data.comm.process_pid = task->pid;
> ev->event_data.comm.process_tgid = task->tgid;
> - get_task_comm(ev->event_data.comm.comm, task);
> +
> + /* This may get truncated. */
> + __get_task_comm(ev->event_data.comm.comm,
> + sizeof(ev->event_data.comm.comm), task);
>
> memcpy(&msg->id, &cn_proc_event_id, sizeof(msg->id));
> msg->ack = 0; /* not used */

__get_task_comm() uses strncpy() which my understanding is, does not add
the nul terminating byte when truncating. Which changes the functionality
here. As all task comms have a terminating byte, the old method would copy
that and include it. This won't add the terminating byte if the buffer is
smaller than the comm, and that might cause issues.

-- Steve

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