linux-kernel - RE: [PATCH] usb: atm: don't use snprintf() for sysfs attrs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3e882693bb344424af37d4d35f3db605@AcuMS.aculab.com>
Date:   Tue, 25 Aug 2020 08:12:05 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Alex Dewar' <alex.dewar90@...il.com>
CC:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        "accessrunner-general@...ts.sourceforge.net" 
        <accessrunner-general@...ts.sourceforge.net>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] usb: atm: don't use snprintf() for sysfs attrs

From: Alex Dewar
> Sent: 24 August 2020 23:23
> kernel/cpu.c: don't use snprintf() for sysfs attrs
> 
> As per the documentation (Documentation/filesystems/sysfs.rst),
> snprintf() should not be used for formatting values returned by sysfs.
> 
> In all of these cases, sprintf() suffices as we know that the formatted
> strings will be less than PAGE_SIZE in length.

Hmmmm....
I much prefer to see bounded string ops.
sysfs really ought to be passing through the buffer length.
The buffer size should probably be SYSFS_BUF_LEN not PAGE_SIZE
(even it happens to typically be the same).
If PAGE_SIZE is big (or small) passing a 4k buffer may be
more appropriate than a PAGE_SIZE one.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)