On Thu, Jul 24, 2025 at 06:06:11PM +0530, Bhupesh wrote: > As Linus mentioned in [1], currently we have several memcpy() use-cases > which use 'current->comm' to copy the task name over to local copies. > For an example: > > ... > char comm[TASK_COMM_LEN]; > memcpy(comm, current->comm, TASK_COMM_LEN); > ... > > These should be modified so that we can later implement approaches > to handle the task->comm's 16-byte length limitation (TASK_COMM_LEN) > in a more modular way (follow-up patch does the same): > > ... > char comm[TASK_COMM_LEN]; > memcpy(comm, current->comm, TASK_COMM_LEN); > comm[TASK_COMM_LEN - 1] = '\0'; > ... Why not switch all of these to get_task_comm()? It will correctly handle the size check and NUL termination. In an earlier thread[1], I pointed out that since __set_task_comm() always keeps a final NUL byte, we're always safe to use strscpy(). (We want to block over-reads and over-writes but don't care about garbled reads.) In the new case of copying into a smaller buffer, strscpy() will always handle writing the final NUL byte. The only special cases I can think of would be non-fixed-sized destination buffers, which get_task_comm() doesn't like since it can't validate how to safely terminate the buffer. The example you give above isn't that, though. -Kees [1] https://lore.kernel.org/all/202411301244.381F2B8D17@keescook/ -- Kees Cook
