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From: Petr Mladek <pmladek@suse.com>
To: John Ogness <john.ogness@linutronix.de>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>
Cc: Linux-Next Mailing List <linux-next@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	open list <linux-kernel@vger.kernel.org>,
	lkft-triage@lists.linaro.org, LTP List <ltp@lists.linux.it>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Rasmus Villemoes <rasmus.villemoes@prevas.dk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Naresh Kamboju <naresh.kamboju@linaro.org>
Subject: Re: [PATCH] printk: ringbuffer: Wrong data pointer when appending small string
Date: Thu, 15 Oct 2020 14:22:46 +0200	[thread overview]
Message-ID: <20201015122246.GD8871@alley> (raw)
In-Reply-To: <20201014175051.GC13775@alley>

On Wed 2020-10-14 19:50:54, Petr Mladek wrote:
> data_realloc() returns wrong data pointer when the block is wrapped and
> the size is not increased. It might happen when pr_cont() wants to
> add only few characters and there is already a space for them because
> of alignment.
> 
> It might cause writing outsite the buffer. It has been detected by LTP
> tests with KASAN enabled:
> 
> Link: https://lore.kernel.org/r/CA+G9fYt46oC7-BKryNDaaXPJ9GztvS2cs_7GjYRjanRi4+ryCQ@mail.gmail.com
> Fixes: 4cfc7258f876a7feba673ac ("printk: ringbuffer: add finalization/extension support")
> Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
> Signed-off-by: Petr Mladek <pmladek@suse.com>

The patch is committed into printk/linux.git, branch for-5.10-fixup.

I am going to send a pull request with it tomorrow unless something
happens in the meantime.

Best Regards,
Petr

      parent reply	other threads:[~2020-10-15 12:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-14 10:49 BUG: KASAN: global-out-of-bounds in vprintk_store on x86_64 Naresh Kamboju
2020-10-14 12:47 ` Sergey Senozhatsky
2020-10-14 14:05 ` Petr Mladek
2020-10-14 15:13   ` Petr Mladek
2020-10-14 17:50     ` [PATCH] printk: ringbuffer: Wrong data pointer when appending small string Petr Mladek
2020-10-15  6:31       ` Sergey Senozhatsky
2020-10-15  9:59         ` John Ogness
2020-10-15 12:22       ` Petr Mladek [this message]

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