Re: [PATCH 0/2] introduce DUMP_PREFIX_UNHASHED for hex dumps

[Steven Rostedt]

On Tue, 26 Jan 2021 10:59:12 -0600
Timur Tabi <timur@xxxxxxxxxx> wrote:

> The only drawback to this idea is: what happens if distros start 
> enabling CONFIG_PRINTK_NEVER_HASH by default, just because it makes 
> debugging easier?

I do believe distros should be more concerned about security than using
this for making debugging easier.

Perhaps we should add the same banner print if that config is set as
trace_printk() has if it is detected in the kernel or a module:

 **********************************************************
 **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
 **                                                      **
 ** trace_printk() being used. Allocating extra memory.  **
 **                                                      **
 ** This means that this is a DEBUG kernel and it is     **
 ** unsafe for production use.                           **
 **                                                      **
 ** If you see this message and you are not debugging    **
 ** the kernel, report this immediately to your vendor!  **
 **                                                      **
 **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
 **********************************************************

But have:

 **********************************************************
 **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
 **                                                      **
 ** CONFIG_PRINTK_NEVER_HASH enabled                     **
 **                                                      **
 ** This means that this is a DEBUG kernel and it is     **
 ** unsafe for production use.                           **
 **                                                      **
 ** If you see this message and you are not debugging    **
 ** the kernel, report this immediately to your vendor!  **
 **                                                      **
 **   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **
 **********************************************************

The above appears to keep people from using trace_printk(), I don't see why
it wouldn't work for this config ;-)

-- Steve