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Message-ID: <2d5f6ffcf47ec4675cde21ff52fc70a9dd13b023.camel@perches.com>
Subject: Re: [PATCH] thinkpad_acpi: fix: use scnprintf instead of snprintf.
From:   Joe Perches <joe@perches.com>
To:     YANG LI <abaci-bugfix@linux.alibaba.com>, hdegoede@redhat.com
Cc:     mgross@linux.intel.com, ibm-acpi@hmh.eng.br,
        ibm-acpi-devel@lists.sourceforge.net,
        platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Wed, 06 Jan 2021 01:01:37 -0800
In-Reply-To: <1609914976-28113-1-git-send-email-abaci-bugfix@linux.alibaba.com>
References: <1609914976-28113-1-git-send-email-abaci-bugfix@linux.alibaba.com>
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On Wed, 2021-01-06 at 14:36 +0800, YANG LI wrote:
> The snprintf() function returns the number of characters which would
> have been printed if there were enough space, but the scnprintf()
> returns the number of characters which were actually printed. If the
> buffer is not large enough, then using snprintf() would result in a
> read overflow and an information leak. This error was found with the
> help of coccicheck.

In all cases, the buffer _is_ large enough.

tmpi is length 5 and ok.
include/sound/core.h:   char shortname[32];             /* short name of this soundcard */
include/sound/core.h:   char longname[80];              /* name of this soundcard */
include/sound/core.h:   char mixername[80];             /* mixer name */

_show function lengths are OK for all the uses with PAGE_SIZE.
And it's probably better to use sysfs_emit for all the _show functions