Re: [PATCH] printk: fix buffer overflow potential for print_text()

[Sergey Senozhatsky]

On (21/01/19 10:00), John Ogness wrote:
> On 2021-01-19, Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> wrote:
> > John, how did you spot these problems?
> 
> I am preparing my series to remove the logbuf_lock, which also refactors
> and consolidates code from syslog_print_all() and
> kmsg_dump_get_buffer(). While testing/verifying my series, I noticed the
> these oddities in the semantics and decided I should research where they
> came from and if they were actually necessary.

Any chance you can put those tests somewhere public so that we can
run them regularly? (say, before Petr sends out a pull request to
Linus.)

> I wouldn't say the oddities are necessary (in fact, they are quite
> annoying), but we have decided to keep them in out of fear of breaking
> out-of-tree modules and/or interesting userspace code.

Sure.

> One positive effect of the rework is that we are finding these oddities
> and documenting them.

Absolutely agree.

	-ss