From: Joe Perches <joe@perches.com>
To: Ben Hutchings <ben@decadent.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>, Kay Sievers <kay@vrfy.org>
Subject: Re: [PATCH v2] drivers/base: Fix length checks in create_syslog_header()/dev_vprintk_emit()
Date: Sun, 08 Jun 2014 19:16:10 -0700 [thread overview]
Message-ID: <1402280170.9150.1.camel@joe-AO725> (raw)
In-Reply-To: <1402267903.23860.45.camel@deadeye.wl.decadent.org.uk>
On Sun, 2014-06-08 at 23:51 +0100, Ben Hutchings wrote:
> snprintf() returns the number of bytes that could have been written
> (excluding the null), not the actual number of bytes written. Given a
> long enough subsystem or device name, these functions will advance
> beyond the end of the on-stack buffer in dev_vprintk_exit(), resulting
> in an information leak or stack corruption. I don't know whether such
> a long name is currently possible.
> In case snprintf() returns a value >= the buffer size, do not add
> structured logging information.
I believe this is guaranteed to be < 128, but
I also suppose it'd be better to emit whatever
buffer is < 128 and add a WARN_ON_ONCE instead.
next prev parent reply other threads:[~2014-06-09 2:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-08 22:51 Ben Hutchings
2014-06-09 2:16 ` Joe Perches [this message]
2014-07-09 23:57 ` Greg Kroah-Hartman
2014-07-11 17:20 ` Ben Hutchings
2014-07-11 18:12 ` Greg Kroah-Hartman
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