From: Alejandro Colomar <alx+linux-hardening@kernel.org>
To: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@linux-mips.org, Ralf Baechle <ralf@linux-mips.org>,
Joe Perches <joe@perches.com>,
Alejandro Colomar <alx@kernel.org>,
linux-hardening@vger.kernel.org,
Krzysztof Kozlowski <krzk@kernel.org>,
"Maciej W. Rozycki" <macro@orcam.me.uk>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Andreas Schwab <schwab@linux-m68k.org>,
Andy Shevchenko <andy@kernel.org>,
Bartosz Golaszewski <brgl@kernel.org>,
Daniel Scally <djrscally@gmail.com>,
Danilo Krummrich <dakr@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Hans Verkuil <hverkuil-cisco@xs4all.nl>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Johan Hovold <johan@kernel.org>, Kees Cook <kees@kernel.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Len Brown <lenb@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linus Walleij <linusw@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Rob Herring <robh@kernel.org>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
Saravana Kannan <saravanak@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
Tom Zanussi <zanussi@kernel.org>,
linux-acpi@vger.kernel.org, driver-core@lists.linux.dev,
linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
linux-gpio@vger.kernel.org,
Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Subject: Off-by-one in arch/mips/bcm47xx/time.c (was: [PATCH v6 02/19] string: Add strprefix())
Date: Sat, 14 Nov 2026 20:49:21 +0100 [thread overview]
Message-ID: <avi54hgKgovNHfKy@devuan> (raw)
In-Reply-To: <c113f651d1ce1b2d42ab9d0c59ae5a0cd17ddb6a.camel@perches.com>
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Hi Hauke,
> Date: 2026-11-14 07:53:25-0800
> From: Joe Perches <joe@perches.com>
>
[...]
> And these are all candidates for converted uses to
> whatever is the function name or steq:
>
> $ git grep -P '[^w]strncmp\s*\(\s*[\w\.\-\>\s]*,\s*\"\w*"\s*,\s*\d+\s*\)' -- '*.[ch]' | wc -l
> 946
Looking at those, I've seen a bug in BCM47XX, introduced in 2224de9d152b
(2013-10-29; "MIPS: BCM47XX: Fix clock detection for BCM5354 with 200MHz
clock").
Look at this line of code:
$ grep strncmp arch/mips/bcm47xx/time.c
if (len >= 0 && !strncmp(buf, "200", 4))
That strncmp(3) call is wrong, as it's really behaving as strcmp(3),
since the 4 is off-by-one. I'd like to know what was the intention.
Was it meant to be !strncmp(buf, "200", 3)? Or was it meant to be just
!strcmp(buf, "200")?
Have a lovely night!
Alex
--
<https://www.alejandro-colomar.es>
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next prev parent reply other threads:[~2026-11-14 19:49 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-14 15:21 [PATCH v6 00/19] Add strprefix() and fix a bug with it Alejandro Colomar
2026-11-14 15:21 ` [PATCH v6 01/19] string: Add streq() Alejandro Colomar
2026-11-14 15:22 ` [PATCH v6 02/19] string: Add strprefix() Alejandro Colomar
2026-11-14 15:28 ` Joe Perches
2026-11-14 17:03 ` Alejandro Colomar
2026-11-14 18:35 ` Alejandro Colomar
2026-11-14 15:53 ` Joe Perches
2026-11-14 16:59 ` Alejandro Colomar
2026-11-14 18:24 ` Joe Perches
2026-11-14 19:00 ` Alejandro Colomar
2026-11-14 19:49 ` Alejandro Colomar [this message]
2026-11-14 15:22 ` [PATCH v6 03/19] string: Document corner-case misbehavior in str_has_prefix() for empty prefix Alejandro Colomar
2026-11-14 15:22 ` [PATCH v6 04/19] device property: Fix fwnode_name_eq() for empty node names Alejandro Colomar
2026-11-14 15:22 ` [PATCH v6 05/19] stddef: Add const_cast() Alejandro Colomar
2026-11-14 15:22 ` [PATCH v6 06/19] string: Add [C]QChar_of() and QVoid_of() Alejandro Colomar
2026-11-14 15:22 ` [PATCH v6 07/19] string: Make strprefix() const-qualifier-generic Alejandro Colomar
2026-11-14 15:22 ` [PATCH v6 08/19] perf map: Use bool for return type instead of int Alejandro Colomar
2026-11-14 15:22 ` [PATCH v6 09/19] string: Make strstarts() a legacy alias for strprefix() Alejandro Colomar
2026-11-14 15:33 ` sashiko-bot
2026-11-14 15:51 ` Alejandro Colomar
2026-11-14 17:52 ` Alejandro Colomar
2026-11-14 15:23 ` [PATCH v6 10/19] platform/x86: hp-bioscfg: Rename local variable Alejandro Colomar
2026-11-14 16:04 ` Joe Perches
2026-11-14 17:08 ` Alejandro Colomar
2026-11-14 15:23 ` [PATCH v6 11/19] treewide: s/strstarts/strprefix/g Alejandro Colomar
2026-11-14 15:23 ` [PATCH v6 12/19] string: Remove strstarts() Alejandro Colomar
2026-11-14 15:29 ` sashiko-bot
2026-11-14 15:45 ` Alejandro Colomar
2026-11-14 15:23 ` [PATCH v6 13/19] s390/test_unwind: Use bool for booleans Alejandro Colomar
2026-11-14 15:23 ` [PATCH v6 14/19] treewide: Replace boolean uses of str_has_prefix() by strprefix() Alejandro Colomar
2026-11-14 15:23 ` [PATCH v6 15/19] treewide: Replace some " Alejandro Colomar
2026-11-14 15:34 ` sashiko-bot
2026-11-14 15:47 ` Alejandro Colomar
2026-11-14 15:23 ` [PATCH v6 16/19] string: Add strsuffix() Alejandro Colomar
2026-11-14 15:24 ` [PATCH v6 17/19] string: Make strends() a legacy alias for strsuffix() Alejandro Colomar
2026-11-14 15:24 ` [PATCH v6 18/19] treewide: s/\<strends\>/strsuffix/g Alejandro Colomar
2026-11-14 15:24 ` [PATCH v6 19/19] string: Remove strends() Alejandro Colomar
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