From: Joe Perches <joe@perches.com>
To: John Ogness <john.ogness@linutronix.de>, Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH next v2 1/2] printk: avoid and/or handle record truncation
Date: Wed, 30 Sep 2020 08:25:24 -0700 [thread overview]
Message-ID: <b4c2ea7ec34aaf05d53264b19a6c40245ed361c0.camel@perches.com> (raw)
In-Reply-To: <20200930090134.8723-2-john.ogness@linutronix.de>
On Wed, 2020-09-30 at 11:07 +0206, John Ogness wrote:
> If a reader provides a buffer that is smaller than the message text,
> the @text_len field of @info will have a value larger than the buffer
> size. If readers blindly read @text_len bytes of data without
> checking the size, they will read beyond their buffer.
>
> Add this check to record_print_text() to properly recognize when such
> truncation has occurred.
>
> Add a maximum size argument to the ringbuffer function to extend
> records so that records can not be created that are larger than the
> buffer size of readers.
>
> When extending records (LOG_CONT), do not extend records beyond
> LOG_LINE_MAX since that is the maximum size available in the buffers
> used by consoles and syslog.
I still think it better to support backspace by rewinding
the buffer rather than truncation of the output.
next prev parent reply other threads:[~2020-09-30 15:25 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 9:01 [PATCH next v2 0/2] printk: fix reading beyond buffer John Ogness
2020-09-30 9:01 ` [PATCH next v2 1/2] printk: avoid and/or handle record truncation John Ogness
2020-09-30 9:43 ` Sergey Senozhatsky
2020-09-30 10:24 ` John Ogness
2020-09-30 11:28 ` Petr Mladek
2020-09-30 11:42 ` John Ogness
2020-09-30 11:53 ` Petr Mladek
2020-09-30 23:25 ` Sergey Senozhatsky
2020-09-30 13:29 ` Petr Mladek
2020-09-30 15:25 ` Joe Perches [this message]
2020-10-01 7:26 ` Petr Mladek
2020-10-01 7:39 ` Joe Perches
2020-10-01 7:54 ` Petr Mladek
2020-09-30 9:01 ` [PATCH next v2 2/2] printk: reduce setup_text_buf size to LOG_LINE_MAX John Ogness
2020-09-30 13:30 ` [PATCH next v2 0/2] printk: fix reading beyond buffer Petr Mladek
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