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From: Petr Mladek <pmladek@suse.com>
To: Josh Law <objecting@objecting.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] lib/vsprintf: fix OOB write in vbin_printf() when size is zero
Date: Mon, 30 Mar 2026 18:17:06 +0200	[thread overview]
Message-ID: <acqiAocX8AHYj5pH@pathway.suse.cz> (raw)
In-Reply-To: <20260324224940.50508-3-objecting@objecting.org>

On Tue 2026-03-24 22:49:38, Josh Law wrote:
> When vbin_printf() is called with size==0, end equals bin_buf and
> the else branch writes end[-1], which is one byte before the buffer.
> 
> Guard the write so it only happens when the buffer is non-empty.
> 
> Signed-off-by: Josh Law <objecting@objecting.org>

Great catch!

There is only one in-tree user and it never passes size=0 so there was
no overflow in the reality. But better be on the safe side.

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr

  reply	other threads:[~2026-03-30 16:17 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-24 22:49 [PATCH 0/4] lib/vsprintf: assorted bug fixes Josh Law
2026-03-24 22:49 ` [PATCH 1/4] lib/vsprintf: always advance args in bstr_printf() pointer path Josh Law
2026-03-30 16:06   ` Petr Mladek
2026-03-24 22:49 ` [PATCH 2/4] lib/vsprintf: fix OOB write in vbin_printf() when size is zero Josh Law
2026-03-30 16:17   ` Petr Mladek [this message]
2026-03-30 16:31   ` Steven Rostedt
2026-03-30 16:32     ` Josh Law
2026-03-30 16:32     ` Josh Law
2026-03-30 16:32     ` Josh Law
2026-03-30 16:34     ` Josh Law
2026-03-24 22:49 ` [PATCH 3/4] lib/vsprintf: use int for field_width in vsscanf() Josh Law
2026-03-25 12:00   ` Andy Shevchenko
2026-03-31 14:31     ` Petr Mladek
2026-03-31 15:35       ` David Laight
2026-03-31 16:12         ` Petr Mladek
2026-03-31 16:13           ` Josh Law
2026-03-31 16:13           ` Josh Law
2026-03-31 16:13           ` Josh Law
2026-04-01 14:22           ` David Laight
2026-04-01 18:29             ` David Laight
2026-03-24 22:49 ` [PATCH 4/4] lib/vsprintf: add missing (u8) cast in format_decode() lookup Josh Law
2026-03-25 12:02   ` Andy Shevchenko
2026-03-31 14:33   ` Petr Mladek
2026-03-31 14:44     ` Josh Law
2026-03-31 14:44     ` Josh Law
2026-03-25 12:05 ` [PATCH 0/4] lib/vsprintf: assorted bug fixes Andy Shevchenko
2026-03-25 17:20   ` Josh Law

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